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1
Liu, Hui, Kavi Devraj, Kerstin Möller, Stefan Liebner, Markus Hecker, and Thomas Korff. "EphrinB-mediated reverse signalling controls junctional integrity and pro-inflammatory differentiation of endothelial cells." Thrombosis and Haemostasis 112, no. 07 (2014): 151–63. http://dx.doi.org/10.1160/th13-12-1034.
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SummaryThe EphB/ephrinB receptor-ligand system is pivotal for the development of the embryonic vasculature and for angiogenesis in the adult organism. We observed that (i) the expression of ephrinB2 and ephrinB1 is up-regulated in capillaries during inflammation, that (ii) these ligands are localised on the luminal endothelial surface, and that (iii) they interact with the ephrinB-receptor EphB2 on monocyte/macrophages. This study delineates the impact of ephrinB-mediated reverse signalling on the integrity and proinflammatory differentiation of the endothelium. To this end, in vitro analyses with human cultured endothelial cells reveal that knockdown of ephrinB2 or ephrinB1 impairs monocyte transmigration through the endothelium. While ephrinB2 but not ephrinB1 interacts with PECAM-1 (CD31) in this context, reverse signalling by ephrinB1 but not ephrinB2 elicits a c-Jun N-terminal kinase (JNK)-dependent up-regulation of E-selectin expression. Furthermore, treatment of endothelial cells with soluble EphB2 receptor bodies or EphB2-overexpressing mouse myeloma cells links ephrinB2 to PECAM-1 and induces its Src-dependent phosphorylation while diminishing Src homology phosphotyrosyl phosphatase-2 (SHP-2) activity and increasing endothelial cell permeability. We conclude that extravasation of EphB2 positive leukocyte populations is facilitated by lowering the integrity of endothelial cell junctions and enhancing the pro-inflammatory phenotype of the endothelium through activation of ephrinB ligands.
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Negrete, Oscar A., David Chu, Hector C. Aguilar, and Benhur Lee. "Single Amino Acid Changes in the Nipah and Hendra Virus Attachment Glycoproteins Distinguish EphrinB2 from EphrinB3 Usage." Journal of Virology 81, no. 19 (2007): 10804–14. http://dx.doi.org/10.1128/jvi.00999-07.
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ABSTRACT The henipaviruses, Nipah virus (NiV) and Hendra virus (HeV), are lethal emerging paramyxoviruses. EphrinB2 and ephrinB3 have been identified as receptors for henipavirus entry. NiV and HeV share similar cellular tropisms and likely use an identical receptor set, although a quantitative comparison of receptor usage by NiV and HeV has not been reported. Here we show that (i) soluble NiV attachment protein G (sNiV-G) bound to cell surface-expressed ephrinB3 with a 30-fold higher affinity than that of sHeV-G, (ii) NiV envelope pseudotyped reporter virus (NiVpp) entered ephrinB3-expressing cells much more efficiently than did HeV pseudotyped particles (HeVpp), and (iii) NiVpp but not HeVpp entry was inhibited efficiently by soluble ephrinB3. These data underscore the finding that NiV uses ephrinB3 more efficiently than does HeV. Henipavirus G chimeric protein analysis implicated residue 507 in the G ectodomain in efficient ephrinB3 usage. Curiously, alternative versions of published HeV-G sequences show variations at residue 507 that can clearly affect ephrinB3 but not ephrinB2 usage. We further defined surrounding mutations (W504A and E505A) that diminished ephrinB3-dependent binding and viral entry without compromising ephrinB2 receptor usage and another mutation (E533Q) that abrogated both ephrinB2 and -B3 usage. Our results suggest that ephrinB2 and -B3 binding determinants on henipavirus G are distinct and dissociable. Global expression analysis showed that ephrinB3, but not ephrinB2, is expressed in the brain stem. Thus, ephrinB3-mediated viral entry and pathology may underlie the severe brain stem neuronal dysfunction seen in fatal Nipah viral encephalitis. Characterizing the determinants of ephrinB2 versus -B3 usage will further our understanding of henipavirus pathogenesis.
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PRESTOZ, LAETITIA, ELLI CHATZOPOULOU, GREGORY LEMKINE, et al. "Control of axonophilic migration of oligodendrocyte precursor cells by Eph–ephrin interaction." Neuron Glia Biology 1, no. 1 (2004): 73–83. http://dx.doi.org/10.1017/s1740925x04000109.
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The migration of oligodendrocyte precursor cells (OPCs) is modulated by secreted molecules in their environment and by cell–cell and matrix–cell interactions. Here, we ask whether membrane-anchored guidance cues, such as the ephrin ligands and their Eph receptors, participate in the control of OPC migration in the optic nerve. We postulate that EphA and EphB receptors, which are expressed on axons of retinal ganglion cells, interact with ephrins on the surface of OPCs. We show the expression of ephrinA5, ephrinB 2 and ephrinB3 in the migrating OPCs of the optic nerve as well as in the diencephalic sites from where they originate. In addition, we demonstrate that coated EphB2-Fc receptors, which are specific for ephrinB2/B3 ligands, induce dramatic changes in the contact and migratory properties of OPCs, indicating that axonal EphB receptors activate ephrinB signaling in OPCs. Based on these findings, we propose that OPCs are characterized by an ephrin code, and that Eph–ephrin interactions between axons and OPCs control the distribution of OPCs in the optic axonal tracts, and the progress and arrest of their migration.
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Yan, Min. "EphrinB-EphB Signaling Induces Hyperalgesia through ERK5/CREB Pathway in Rats." May 2017 4, no. 20;4 (2017): E563—E574. http://dx.doi.org/10.36076/ppj.2017.e574.
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Background: There are numerous studies implicating that EphB receptors and ephrinB ligands play important roles in modulating the transduction of spinal nociceptive information. EphrinB-EphB signaling may contribute to hyperalgesia via various kinds of downstream molecules, the mechanisms of which have not been completely understood. Objective: The aim of the present study was to identify whether ephrinB-EphB signaling could contribute to hyperalgesia through ERK5/CREB pathway. Study Design: Controlled animal study. Setting: University laboratory. Methods: This study attempted to detect the changes of pain behaviors and the protein level of p-ERK5 and p-CREB by activating EphB receptors in the spinal cord of rats. To further confirm our hypothesis, we designed LV-siRNA for knockdown of spinal ERK5. When ERK5 was inhibited, we recorded the changes of spinal p-CREB expression and the pain behaviors of rats after activating EphB receptors. We also confirmed this conclusion in rat CCI model. Statistical analyses were performed using GraphPad Prism 5. Results: Intrathecal injection of ephrinB2-Fc in rats evoked thermal hyperalgesia and mechanical allodynia, along with activation of ERK5 and CREB in the spinal cord. Knockdown of ERK5 inhibited ephrinB2-Fc-induced CREB activation and hyperalgesia. Blocking EphB receptors prevented CCI-induced neuropathic pain and spinal ERK5/CREB activation. Limitations: More underlying mechanisms that underlie the relationship between ephrinBEphB signaling and ERK5/CREB pathway will need to be explored in future studies. Conclusions: Our study suggests that ERK5/CREB pathway plays important roles in the transduction of nociceptive information associated with ephrinB-EphB signaling. This study provides further understanding of the downstream mechanisms of ephrinB-EphB signaling and helps to explore new targets for treating pathological pain. Key words: EphrinB-EphB signaling, MAPK, ERK5, CREB, hyperalgesia, pain, CCI, NMDA
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Kitamura, Takuya, Yukihito Kabuyama, Akihisa Kamataki, et al. "Enhancement of lymphocyte migration and cytokine production by ephrinB1 system in rheumatoid arthritis." American Journal of Physiology-Cell Physiology 294, no. 1 (2008): C189—C196. http://dx.doi.org/10.1152/ajpcell.00314.2007.
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Although the etiology of early events in rheumatoid arthritis (RA) remains undefined, an anomaly in T cell homeostasis and hyperproliferation of synovial-lining cells are involved in the disease process. Since it has been reported that the ephrin/Eph receptor system plays important signaling roles in inflammation processes, we attempted to examine ephrinB molecules in T cells and synovial cells derived from RA in this study. The expression level of ephrinB1 was significantly high in synovial fibroblasts and CD3-positive exudate lymphocytes in synovial tissues derived from patients with RA compared with those in osteoarthritis (OA). Protein and mRNA levels of ephrinB1 were also higher in peripheral blood lymphocytes (PBLs) prepared from patients with RA than those from normal controls. Similar results were obtained from an animal model of human RA, collagen antibody-induced arthritis mice. Moreover, a recombinant ephrinB1/Fc fusion protein stimulated normal PBLs to exhibit enhanced migration and production of TNF-α. EphrinB1/Fc also activated synovial cells established from patients with RA to produce IL-6. Tyrosine phosphorylation of EphB1 was induced in these cells by ephrinB1/Fc. The CpG islands in the 5′ upstream regulatory region of the ephrinB1 gene were hypomethylated in RA patients compared with those of normal donors. These results suggest that ephrinB1 and EphB1 receptors play an important role in the inflammatory states of RA, especially by affecting the population and function of T cells. Inhibition of the ephrinB/EphB system might be a novel target for the treatment of RA.
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BONG, Yong-Sik, Yeon-Hwa PARK, Hyun-Shik LEE, Kathleen MOOD, Akihiko ISHIMURA, and Ira O. DAAR. "Tyr-298 in ephrinB1 is critical for an interaction with the Grb4 adaptor protein." Biochemical Journal 377, no. 2 (2004): 499–507. http://dx.doi.org/10.1042/bj20031449.
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The Eph family of receptor tyrosine kinases and their membrane-bound ligands, the ephrins, are thought to play a role in the regulation of cell adhesion and migration during development by mediating cell-to-cell signalling events. The transmembrane ephrinB protein is a bidirectional signalling molecule that sends a forward signal through the activation of its cognate receptor tyrosine kinase residing on another cell. The reverse signal is transduced into the ephrinB-expressing cell via tyrosine phosphorylation of its conserved C-terminal cytoplasmic domain. Previous work from our laboratory has implicated the activated FGFR1 (fibroblast growth factor receptor 1) as a regulator of a de-adhesion signal that results from overexpression of ephrinB1. In the present study, we report the isolation of Xenopus Grb4 (growth-factor-receptor-bound protein 4), an ephrinB1-interacting protein, and we show that when expressed in Xenopus oocytes, ephrinB1 interacts with Grb4 in the presence of an activated FGFR1. Amino acid substitutions were generated in Grb4, and the resulting mutants were expressed along with ephrinB1 and an activated FGFR in Xenopus oocytes. Co-immunoprecipitation analysis shows that the FLVR motif within the Src homology 2 domain of Xenopus Grb4 is vital for this phosphorylation-dependent interaction with ephrinB1. More importantly, using deletion and substitution analysis we identify the tyrosine residue at position 298 of ephrinB1 as being required for the physical interaction with Grb4, whereas Tyr-305 and Tyr-310 are dispensable. Moreover, we show that the region between amino acids 301 and 304 of ephrinB1 is also required for this critical tyrosine-phosphorylation-dependent event.
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Bishop, Kimberly A., Tzanko S. Stantchev, Andrew C. Hickey, et al. "Identification of Hendra Virus G Glycoprotein Residues That Are Critical for Receptor Binding." Journal of Virology 81, no. 11 (2007): 5893–901. http://dx.doi.org/10.1128/jvi.02022-06.
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ABSTRACT Hendra virus (HeV) is an emerging paramyxovirus capable of infecting and causing disease in a variety of mammalian species, including humans. The virus infects its host cells through the coordinated functions of its fusion (F) and attachment (G) glycoproteins, the latter of which is responsible for binding the virus receptors ephrinB2 and ephrinB3. In order to identify the receptor binding site, a panel of G glycoprotein constructs containing mutations was generated using an alanine-scanning mutagenesis strategy. Based on a predicted G structure, charged amino acids residing in regions that could be homologous to those in the measles virus H attachment glycoprotein known to be involved in its protein receptor interaction were targeted. Using a coprecipitation-based assay, seven single-amino-acid substitutions in HeV G were identified as having significantly impaired binding to both the ephrinB2 and ephrinB3 viral receptors: D257A, D260A, G439A, K443A, G449A, K465A, and D468A. The impairment of receptor interaction conferred a concomitant diminution in their abilities to promote membrane fusion when coexpressed with F. The G glycoprotein mutants were also recognized by three or more conformation-dependent monoclonal antibodies of a panel of five, were expressed on the cell surface, and retained their abilities to bind and coprecipitate F. Interestingly, some of these mutant G glycoproteins coprecipitated with F more efficiently than wild-type G. Taken together, these data provide strong biochemical and functional evidence that some of these residues could be part of a conformation-dependent, discontinuous, and overlapping ephrinB2 and -B3 binding domain within the HeV G glycoprotein.
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Lee, Benhur, Olivier Pernet, Asim A. Ahmed, Antra Zeltina, Shannon M. Beaty, and Thomas A. Bowden. "Molecular recognition of human ephrinB2 cell surface receptor by an emergent African henipavirus." Proceedings of the National Academy of Sciences 112, no. 17 (2015): E2156—E2165. http://dx.doi.org/10.1073/pnas.1501690112.
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The discovery of African henipaviruses (HNVs) related to pathogenic Hendra virus (HeV) and Nipah virus (NiV) from Southeast Asia and Australia presents an open-ended health risk. Cell receptor use by emerging African HNVs at the stage of host-cell entry is a key parameter when considering the potential for spillover and infection of human populations. The attachment glycoprotein from a Ghanaian bat isolate (GhV-G) exhibits <30% sequence identity with Asiatic NiV-G/HeV-G. Here, through functional and structural analysis of GhV-G, we show how this African HNV targets the same human cell-surface receptor (ephrinB2) as the Asiatic HNVs. We first characterized this virus−receptor interaction crystallographically. Compared with extant HNV-G–ephrinB2 structures, there was significant structural variation in the six-bladed β-propeller scaffold of the GhV-G receptor-binding domain, but not the Greek key fold of the bound ephrinB2. Analysis revealed a surprisingly conserved mode of ephrinB2 interaction that reflects an ongoing evolutionary constraint among geographically distal and phylogenetically divergent HNVs to maintain the functionality of ephrinB2 recognition during virus–host entry. Interestingly, unlike NiV-G/HeV-G, we could not detect binding of GhV-G to ephrinB3. Comparative structure–function analysis further revealed several distinguishing features of HNV-G function: a secondary ephrinB2 interaction site that contributes to more efficient ephrinB2-mediated entry in NiV-G relative to GhV-G and cognate residues at the very C terminus of GhV-G (absent in Asiatic HNV-Gs) that are vital for efficient receptor-induced fusion, but not receptor binding per se. These data provide molecular-level details for evaluating the likelihood of African HNVs to spill over into human populations.
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Ruan, Jia-Ping, Hong-Xing Zhang, Xian-Fu Lu, Yue-Peng Liu, and Jun-Li Cao. "EphrinBs/EphBs Signaling Is Involved in Modulation of Spinal Nociceptive Processing through a Mitogen-activated Protein Kinases-dependent Mechanism." Anesthesiology 112, no. 5 (2010): 1234–49. http://dx.doi.org/10.1097/aln.0b013e3181d3e0df.
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Background Our previous studies have demonstrated that EphBs receptors and ephrinBs ligands were involved in modulation of spinal nociceptive information. However, the downstream mechanisms that control this process are not well understood. The aim of this study was to further investigate whether mitogen-activated protein kinases (MAPKs), as the downstream effectors, participate in modulation of spinal nociceptive information related to ephrinBs/EphBs. Methods Thermal hyperalgesia and mechanical allodynia were measured using radiant heat and von Frey filaments test. Immunofluorescence staining was used to detect the expression of p-MAPKs and of p-MAPKs/neuronal nuclei, or p-MAPKs/glial fibrillary acidic protein double label. C-Fos expression was determined by immunohistochemistry. The expression of p-MAPKs was also determined by Western blot assay. Results Intrathecal injection of ephrinB1-Fc produced a dose- and time-dependent thermal and mechanical hyperalgesia, accompanied by the increase of spinal p-MAPKs and c-Fos expression. Immunofluorescence staining revealed that p-MAPKs colocalized with the neuronal marker (neuronal nuclei) and the astrocyte marker (glial fibrillary acidic protein). Inhibition of MAPKs prevented and reversed pain behaviors and the increase of spinal c-Fos expression induced by intrathecal injection of ephrinB1-Fc. Inhibition of EphBs receptors by intrathecal injection of EphB1-Fc reduced formalin-induced inflammation and chronic constrictive injury-induced neuropathic pain behaviors accompanied by decreased expression of spinal p-MAPKs and c-Fos protein. Furthermore, pretreatment with MK-801, an N-methyl-d-aspartate receptor antagonist, prevented behavioral hyperalgesia and activation of spinal MAPKs induced by intrathecal injection of ephrinB1-Fc. Conclusions These results demonstrated that activation of MAPKs contributed to modulation of spinal nociceptive information related to ephrinBs/EphBs.
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Wu, Hsi-Chin, Chao-Hsiang Chang, Hsien-Yu Peng, et al. "EphrinB2 induces pelvic-urethra reflex potentiation via Src kinase-dependent tyrosine phosphorylation of NR2B." American Journal of Physiology-Renal Physiology 300, no. 2 (2011): F403—F411. http://dx.doi.org/10.1152/ajprenal.00520.2010.
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Recently, the role of EphB receptor (EphBR) tyrosine kinase and their ephrinB ligands in pain-related neural plasticity at the spinal cord level have been identified. To test whether Src-family tyrosine kinase-dependent glutamatergic N-methyl-d-aspartate receptor NR2B subunit phosphorylation underlies lumbosacral spinal EphBR activation to mediate pelvic-urethra reflex potentiation, we recorded external urethra sphincter electromyogram reflex activity and analyzed protein expression in the lumbosacral (L6-S2) dorsal horn in response to intrathecal ephrinB2 injections. When compared with vehicle solution, exogenous ephrinB2 (5 μg/rat it)-induced reflex potentiation, in associated with phosphorylation of EphB1/2, Src-family kinase, NR2B Y1336 and Y1472 tyrosine residues. Both intrathecal EphB1 and EphB2 immunoglobulin fusion protein (both 10 μg/rat it) prevented ephrinB2-dependent reflex potentiation, as well as protein phosphorylation. Pretreatment with PP2 (50 μM, 10 μl it), an Src-family kinase antagonist, reversed the reflex potentiation, as well as Src kinase and NR2B phosphorylation. Together, these results suggest the ephrinB2-dependent EphBR activation, which subsequently provokes Src kinase-mediated N-methyl-d-aspartate receptor NR2B phosphorylation in the lumbosacral dorsal horn, is crucial for the induction of spinal reflex potentiation contributing to the development of visceral pain and/or hyperalgesia in the pelvic area.
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Riedl, Jurgen A., Dominique T. Brandt, Eduard Batlle, Leo S. Price, Hans Clevers, and Johannes L. Bos. "Down-regulation of Rap1 activity is involved in ephrinB1-induced cell contraction." Biochemical Journal 389, no. 2 (2005): 465–69. http://dx.doi.org/10.1042/bj20050048.
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Ephrins are cell surface ligands that activate Eph receptor tyrosine kinases. This ligand–receptor interaction plays a central role in the sorting of cells. We have previously shown that the ephrinB–EphB signalling pathway is also involved in the migration of intestinal precursor cells along the crypts. Using the colon cell line DLD1 expressing the EphB2 receptor, we showed that stimulation of these cells with soluble ephrinB1 results in a rapid retraction of cell extensions and a detachment of cells. On ephrinB1 stimulation, the small GTPases Rho and Ras are activated and Rap1 is inactivated. Importantly, when a constitutively active Rap1 mutant was introduced into these cells, ephrinB1-induced retraction was inhibited. From these results, we conclude that down-regulation of Rap1 is a prerequisite for ephrin-induced cell retraction in colon cells.
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Aguilar, Hector C., Vanessa Aspericueta, Lindsey R. Robinson, Karen E. Aanensen, and Benhur Lee. "A Quantitative and Kinetic Fusion Protein-Triggering Assay Can Discern Distinct Steps in the Nipah Virus Membrane Fusion Cascade." Journal of Virology 84, no. 16 (2010): 8033–41. http://dx.doi.org/10.1128/jvi.00469-10.
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ABSTRACT The deadly paramyxovirus Nipah virus (NiV) contains a fusion glycoprotein (F) with canonical structural and functional features common to its class. Receptor binding to the NiV attachment glycoprotein (G) triggers F to undergo a two-phase conformational cascade: the first phase progresses from a metastable prefusion state to a prehairpin intermediate (PHI), while the second phase is marked by transition from the PHI to the six-helix-bundle hairpin. The PHI can be captured with peptides that mimic F's heptad repeat regions, and here we utilized a NiV heptad repeat peptide to quantify PHI formation and the half-lives (t 1/2) of the first and second fusion cascade phases. We found that ephrinB2 receptor binding to G triggered ∼2-fold more F than that triggered by ephrinB3, consistent with the increased rate and extent of fusion observed with ephrinB2- versus ephrinB3-expressing cells. In addition, for a series of hyper- and hypofusogenic F mutants, we quantified F-triggering capacities and measured the kinetics of their fusion cascade phases. Hyper- and hypofusogenicity can each be manifested through distinct stages of the fusion cascade, giving rise to vastly different half-lives for the first (t 1/2, 1.9 to 7.5 min) or second (t 1/2, 1.5 to 15.6 min) phase. While three mutants had a shorter first phase and a longer second phase than the wild-type protein, one mutant had the opposite phenotype. Thus, our results reveal multiple critical parameters that govern the paramyxovirus fusion cascade, and our assays should help efforts to elucidate other class I membrane fusion processes.
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Zhou, Xuan, Liu Xiaoli, Na Xu, et al. "EphrinB2/EphB4 Interaction Promotes Myeloid Leukemia Cell Invasion through RhoA-Mediated Mechanism." Blood 124, no. 21 (2014): 1018. http://dx.doi.org/10.1182/blood.v124.21.1018.1018.
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Abstract Background and Objective: Several studies have reported the up-regulation of EphB receptor-tyrosine kinases and ephrinB ligands in a variety of tumors, suggesting a functional relation between EphB/ephrinB signaling and tumor progression. However, how they regulate the invasiveness of myeloid leukemia cells were still unknown. Our previously study suggested that EphB4 were highly expressed in patients with extramedullary leukemia compared with patients without extramedullary leukemia, which indicated that the expression of EphB4 was related with myeloid leukemia cell invasion. To address the molecular mechanism, we aimed to characterize the role of EphB4 and ephrinB2 ligands in the interaction of myeloid leukemia cells. Methods: To clarify the question, myeloid leukemia cell lines (K562 cells and THP-1 cells) treated with clustered ephrinA1–Fc proteins, ephrinB2–Fc proteins and Fc proteins were cultured in vitro, then migration and invasion were determined by transwell assay according to different time. Pulldown western immunoblot analysis were used to detect the level of GTP-RhoA and total RhoA; the phosphorylation of EphB4 and MMP9 expression were also determined by immunoblot analysis before and after the treatment of different clustered Fc proteins. Results: The results showed that after ephrinB2–Fc stimulation, the numbers of K562 cells migrating through transwell chamber were significantly enhanced compared to Fc proteins stimulation (1.85-fold, P=0.033), meanwhile, the numbers of K562 cells invading the matrigel also enhanced (1.46 -fold, P=0.025). However, the numbers of K562 cells migrating through transwell chamber after ephrinA1–Fc stimulation didn’t significantly increase compared to Fc proteins stimulation (P=0.411), and the numbers of K562 cells invading the matrigel also didn’t enhanced (P=0.072) after ephrinA1–Fc stimulation. Moreover, after ephrinB2–Fc stimulation, the numbers of THP-1 cells migrating through transwell chamber were significantly enhanced compared to Fc proteins stimulation (2.25-fold, P<0.01), meanwhile, the numbers of THP-1 cells invading the matrigel also enhanced (1.66 -fold, P<0.01). However, the numbers of THP-1 cells migrating through transwell chamber and the numbers of THP-1 cells invading the matrigel didn’t significantly enhanced (P>0.05, P>0.05) after ephrinA1–Fc stimulation. Furthermore, EphB4 immunoprecipitation followed by immunoblotting with anti-phosphotyrosine antibody revealed that EphB4 is phosphorylated on tyrosine in K562 cells after ephrinB2–Fc stimulation. Additionally, the level of active RhoA (GTP-RhoA) and MMP9 in K562 cells were both significantly increased in response to EphB4 receptor activation with its ligand ephrin-B2-Fc ( P<0.05). Conclusions: These findings suggested that EphB4/EprinB2 signaling played an important role in myeloid leukemia cells progression by promoting their migratory ability, activating RhoA activity and increasing MMP9 expression. Our findings reveal a novel regulation of this intriguing receptor/ligand family that contributes to the cell invasiveness of myeloid leukemia cells. Disclosures No relevant conflicts of interest to declare.
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Kumar, R. Sreeraman, R. J. B. Macaulay, H. C. Rutherford, N. Barkey, J. Koomen, and D. L. Morse. "EphrinB3 and EphrinB4 Receptors are potential therapeutic targets in glioblastoma." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 42, S3 (2015): S4. http://dx.doi.org/10.1017/cjn.2015.373.
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Peng, Hsien-Yu, Gin-Den Chen, Cheng-Hung Lai, Kwong-Chung Tung, Junn-Liang Chang, and Tzer-Bin Lin. "Endogenous ephrinB2 mediates colon-urethra cross-organ sensitization via Src kinase-dependent tyrosine phosphorylation of NR2B." American Journal of Physiology-Renal Physiology 298, no. 1 (2010): F109—F117. http://dx.doi.org/10.1152/ajprenal.00287.2009.
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Recently, the role of EphB receptor (EphBR) tyrosine kinase and their ephrinB ligands in spinal pain-related neural plasticity has been identified. To test whether Src-family non-receptor tyrosine kinase-dependent glutamatergic N-methyl-d-aspartate receptor (NMDAR) NR2B subunit phosphorylation underlies lumbosacral spinal EphBR activation to mediate cross-organ sensitization between the colon and the urethra, external urethra sphincter electromyogram activity evoked by pelvic nerve stimulation and protein expression in the lumbosacral (L6–S2) dorsal horn were studied before and after intracolonic mustard oil (MO) instillation. We found MO instillation produced colon-urethra reflex sensitization along with an upregulation of endogenous ephrinB2 expression as well as phosphorylation of EphB1/2, Src-family kinase, and NR2B tyrosine residues. Intrathecal immunoglobulin fusion protein of EphB1 and EphB2 as well as PP2 reversed the reflex sensitization and NR2B phosphorylation caused by MO. All these results suggest that EphBR-ephrinB interactions, which provoke Src-family kinase-dependent NMDAR NR2B phosphorylation at the lumbosacral spinal cord level, are involved in cross-organ sensitization, contributing to the development of viscero-visceral referred pain between the bowel and the urethra.
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Luo, Hongyu, Bieke Broux, Xuehai Wang, et al. "EphrinB1 and EphrinB2 regulate T cell chemotaxis and migration in experimental autoimmune encephalomyelitis and multiple sclerosis." Neurobiology of Disease 91 (July 2016): 292–306. http://dx.doi.org/10.1016/j.nbd.2016.03.013.
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Gerety, Sebastian S., and David J. Anderson. "Cardiovascular ephrinB2 function is essential for embryonic angiogenesis." Development 129, no. 6 (2002): 1397–410. http://dx.doi.org/10.1242/dev.129.6.1397.
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EphrinB2, a transmembrane ligand of EphB receptor tyrosine kinases, is specifically expressed in arteries. In ephrinB2 mutant embryos, there is a complete arrest of angiogenesis. However, ephrinB2 expression is not restricted to vascular endothelial cells, and it has been proposed that its essential function may be exerted in adjacent mesenchymal cells. We have generated mice in which ephrinB2 is specifically deleted in the endothelium and endocardium of the developing vasculature and heart. We find that such a vascular-specific deletion of ephrinB2 results in angiogenic remodeling defects identical to those seen in the conventional ephrinB2 mutants. These data indicate that ephrinB2 is required specifically in endothelial and endocardial cells for angiogenesis, and that ephrinB2 expression in perivascular mesenchyme is not sufficient to compensate for the loss of ephrinB2 in these vascular cells.
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Fehnel, Katie Pricola, David L. Penn, Micah Duggins-Warf, et al. "Dysregulation of the EphrinB2−EphB4 ratio in pediatric cerebral arteriovenous malformations is associated with endothelial cell dysfunction in vitro and functions as a novel noninvasive biomarker in patients." Experimental & Molecular Medicine 52, no. 4 (2020): 658–71. http://dx.doi.org/10.1038/s12276-020-0414-0.
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Abstract We investigated (1) EphrinB2 and EphB4 receptor expression in cerebral AVMs, (2) the impact of an altered EphrinB2:EphB4 ratio on brain endothelial cell function and (3) potential translational applications of these data. The following parameters were compared between AVM endothelial cells (AVMECs) and human brain microvascular endothelial cells (HBMVECs): quantified EphrinB2 and EphB4 expression, angiogenic potential, and responses to manipulation of the EphrinB2:EphB4 ratio via pharmacologic stimulation/inhibition. To investigate the clinical relevance of these in vitro data, Ephrin expression was assessed in AVM tissue (by immunohistochemistry) and urine (by ELISA) from pediatric patients with AVM (n = 30), other cerebrovascular disease (n = 14) and control patients (n = 29), and the data were subjected to univariate and multivariate statistical analyses. Compared to HBMVECs, AVMECs demonstrated increased invasion (p = 0.04) and migration (p = 0.08), impaired tube formation (p = 0.06) and increased EphrinB2:EphB4 ratios. Altering the EphrinB2:EphB4 ratio (by increasing EphrinB2 or blocking EphB4) in HBMVECs increased invasion (p = 0.03 and p < 0.05, respectively). EphrinB2 expression was increased in AVM tissue, which correlated with increased urinary EphrinB2 levels in AVM patients. Using the optimal urinary cutoff value (EphrinB2 > 25.7 pg/μg), AVMs were detected with high accuracy (80% vs. controls) and were distinguished from other cerebrovascular disease (75% accuracy). Post-treatment urinary EphrinB2 levels normalized in an index patient. In summary, AVMECs have an EphrinB2:EphB4 ratio that is increased compared to that of normal HBMVECs. Changing this ratio in HBMVECs induces AVMEC-like behavior. EphrinB2 is clinically relevant, and its levels are increased in AVM tissue and patient urine. This work suggests that dysregulation of the EphrinB2:EphB4 signaling cascade and increases in EphrinB2 may play a role in AVM development, with potential utility as a diagnostic and therapeutic target.
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Xing, Shihui, Nannan Pan, Wei Xu та ін. "EphrinB2 activation enhances angiogenesis, reduces amyloid-β deposits and secondary damage in thalamus at the early stage after cortical infarction in hypertensive rats". Journal of Cerebral Blood Flow & Metabolism 39, № 9 (2018): 1776–89. http://dx.doi.org/10.1177/0271678x18769188.
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Cerebral infarction causes secondary neurodegeneration and angiogenesis in thalamus, which impacts functional recovery after stroke. Here, we hypothesize that activation of ephrinB2 could stimulate angiogenesis and restore the secondary neurodegeneration in thalamus after cerebral infarction. Focal cerebral infarction was induced by middle cerebral artery occlusion (MCAO). Secondary damage, angiogenesis, amyloid-β (Aβ) deposits, levels of ephrinB2 and receptor for advanced glycation end product (RAGE) in the ipsilateral thalamus were determined by immunofluorescence and immunoblot. The contribution of ephrinB2 to angiogenesis was determined by siRNA-mediated knockdown of ephrinB2 and pharmacological activation of ephrinB2. The results showed that formation of new vessels and ephrinB2 expression was markedly increased in the ipsilateral thalamus at seven days after MCAO. EphrinB2 knockdown markedly suppressed angiogenesis coinciding with increased Aβ accumulation, neuronal loss and gliosis in the ipsilateral thalamus. In contrast, clustered EphB2-Fc significantly enhanced angiogenesis, alleviated Aβ accumulation and the secondary thalamic damage, which was accompanied by accelerated function recovery. Additionally, activation of ephrinB2 significantly reduced RAGE levels in the ipsilateral thalamus. Our findings suggest that activation of ephrinB2 promotes angiogenesis, ameliorates Aβ accumulation and the secondary thalamic damage after cerebral infarction. Additionally, RAGE might be involved in Aβ clearance by activating ephrinB2 in the thalamus.
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Zhu, Min, Yu Hua, Jian Tang, Xiaoke Zhao, Ling Zhang, and Yue Zhang. "Lentiviral-mediated ephrin B2 gene modification of rat bone marrow mesenchymal stem cells." Journal of International Medical Research 47, no. 7 (2019): 3282–98. http://dx.doi.org/10.1177/0300060519843023.
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Objective To determine the effect of the upregulation or knockdown of the ephrinB2 ( Efnb2) gene and the effect of EphB4/EphrinB2 signalling in rat bone marrow mesenchymal stem cells (BMSCs). Methods Rat BMSCs were infected with lentivirus vectors carrying EphrinB2 and shRNA-EphrinB2. EphrinB2 mRNA and protein levels were quantified. At 28 days of culture with neuronal cell-conditioned differentiation medium, levels of microtubule-associated protein 2 (MAP2), CD133 and nestin were detected in EphrinB2/BMSCs and shEphrinB2/BMSCs using quantitative polymerase chain reaction and immunofluorescence. The ability of these cells to migrate was evaluated using a transwell assay. Results BMSCs were successfully isolated as indicated by their CD90+ CD29+ CD34– CD45– phenotype. Three days after ephrinB2 transduction, BMSC cell bodies began to shrink and differentiate into neuron-like cells. At 28 days, levels of MAP2, CD133 and nestin, as well as the number of migratory cells, were higher in lenti-EphrinB2-BMSCs than in the two control groups. The shEphrinB2/BMSCs had reduced levels of MAP2, CD133 and nestin; and a lower rate of cell migration. Similarly, increased levels of Grb4 andp21-activated kinase in the EphB4/EphrinB2 reverse signalling pathway were observed by Western blot. Conclusions LV-EphrinB2 can be efficiently transduced into BMSCs, which then differentiate into neuron-like cells.
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Wang, Penglai, Wen Wang, Tengyu Geng, et al. "EphrinB2 regulates osteogenic differentiation of periodontal ligament stem cells and alveolar bone defect regeneration in beagles." Journal of Tissue Engineering 10 (January 2019): 204173141989436. http://dx.doi.org/10.1177/2041731419894361.
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EphrinB2, a membrane protein regulating bone homeostasis, has been demonstrated to induce osteogenic gene expression in periodontal ligament fibroblasts. The aim of this study was to explore the effects of ephrinB2 on osteogenic differentiation of periodontal ligament stem cells and on alveolar bone regeneration in vivo. We assessed the osteogenic gene expression and osteogenic differentiation potential of ephrinB2-modified human and canine periodontal ligament stem cells, in which ephrinB2 expression was upregulated via lentiviral vector transduction. EphrinB2-modified canine periodontal ligament stem cells combined with PuraMatrix were delivered to critical-sized alveolar bone defects in beagles to evaluate bone regeneration. Results showed that ephrinB2 overexpression enhanced osteogenic gene transcription and mineral deposition in both human and canine periodontal ligament stem cells. Animal experiments confirmed that ephrinB2-modified canine periodontal ligament stem cells + PuraMatrix resulted in greater trabecular bone volume per tissue volume and trabecular thickness compared with other groups. Our study demonstrated that ephrinB2 promoted osteogenic differentiation of periodontal ligament stem cells and alveolar bone repair in beagles, highlighting its therapeutic potential for the treatment of alveolar bone damage.
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Korff, Thomas, Jennifer Braun, Dennis Pfaff, Hellmut G. Augustin, and Markus Hecker. "Role of ephrinB2 expression in endothelial cells during arteriogenesis: impact on smooth muscle cell migration and monocyte recruitment." Blood 112, no. 1 (2008): 73–81. http://dx.doi.org/10.1182/blood-2007-12-128835.
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Abstract Expression of the arterial marker molecule ephrinB2 in endothelial cells is a prerequisite for adequate remodeling processes of the developing or angiogenic vasculature. Although its role in these processes has been extensively studied, the impact of ephrinB2 on the remodeling of adult arteries is largely unknown. To this end, we analyzed its expression during a biomechanically induced arteriolar remodeling process known as arteriogenesis and noted a significant increase in ephrinB2 expression under these conditions. By examining those biomechanical forces presumed to drive arteriogenesis, we identified cyclic stretch as a critical inducer of ephrinB2 expression in endothelial cells. Subsequent functional analyses in vitro revealed that endothelial cells expressing ephrinB2 limit the migration of smooth muscle cells, thereby enhancing segregation of both cell types. Moreover, MCP-1 induced transmigration of monocytes through a monolayer of endothelial cells overexpressing a truncated variant of ephrinB2 was clearly impeded. Taken together, these data suggest that expression of ephrinB2 in adult endothelial cells is up-regulated during arterial remodeling and controlled by cyclic stretch, a well-known inducer of such processes. This stretch-induced ephrinB2 expression may be pivotal for arteriogenesis as it limits smooth muscle cell migration within defined borders and controls monocyte extravasation.
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Pennisi, Angela, Wen Ling, Xin Li, et al. "The ephrinB2/EphB4 axis is dysregulated in osteoprogenitors from myeloma patients and its activation affects myeloma bone disease and tumor growth." Blood 114, no. 9 (2009): 1803–12. http://dx.doi.org/10.1182/blood-2009-01-201954.
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Myeloma bone disease is caused by uncoupling of osteoclastic bone resorption and osteoblastic bone formation. Bidirectional signaling between the cell-surface ligand ephrinB2 and its receptor, EphB4, is involved in the coupling of osteoblastogenesis and osteoclastogenesis and in angiogenesis. EphrinB2 and EphB4 expression in mesenchymal stem cells (MSCs) from myeloma patients and in bone cells in myelomatous bones was lower than in healthy counterparts. Wnt3a induced up-regulation of EphB4 in patient MSCs. Myeloma cells reduced expression of these genes in MSCs, whereas in vivo myeloma cell-conditioned media reduced EphB4 expression in bone. In osteoclast precursors, EphB4-Fc induced ephrinB2 phosphorylation with subsequent inhibition of NFATc1 and differentiation. In MSCs, EphB4-Fc did not induce ephrinB2 phosphorylation, whereas ephrinB2-Fc induced EphB4 phosphorylation and osteogenic differentiation. EphB4-Fc treatment of myelomatous SCID-hu mice inhibited myeloma growth, osteoclastosis, and angiogenesis and stimulated osteoblastogenesis and bone formation, whereas ephrinB2-Fc stimulated angiogenesis, osteoblastogenesis, and bone formation but had no effect on osteoclastogenesis and myeloma growth. These chimeric proteins had similar effects on normal bone. Myeloma cells expressed low to undetectable ephrinB2 and EphB4 and did not respond to the chimeric proteins. The ephrinB2/EphB4 axis is dysregulated in MM, and its activation by EphB4-Fc inhibits myeloma growth and bone disease.
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Lin, Li, Xu Na, Jiang Zhiwu, et al. "EphB4/ephrinB2 ephrinB1 Interaction Mediated Chronic Myelogenous Leukemia Mesenchymal Stromal Cells Osteogenic Differentiation in Vitro and In Vivo." Blood 128, no. 22 (2016): 1901. http://dx.doi.org/10.1182/blood.v128.22.1901.1901.
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Abstract Background and Objective: Osteoblasts, important of stromal cells in bone marrow microenvironment, maintain HSCs in resting state and protect its' functions. Osteoblasts derived from mesenchymal stem cells (MSCs), which can be differentiated into osteoblast in bone marrow under the regulation of cytokines. Recent studies have indicated that EphB4/ephrinB2 protein participates in the regulation of osteogenesis differentiation of MSCs in bone marrow microenvironment. Our previous study found that EphB4 receptor was over expressed in CML patients and cell lines, which played an important role to change characterize of Imatinib(IM)-resistant in chronic myeloid leukemia cells. Furthermore, we performed experiments to prove that osteogenic differentiation in MSCs from CML-initial patient significantly higher in contrast to normal human MSCs and the change of EphB4 molecules on leukemia cells may transform MSCs functions in vitro. However, the mechanism of these transformations of MSCs in vitro and what is change in vivo were still unclear. Therefore, we hypothesis that the change of EphB4 molecules on leukemia cells might play an important role to osteogenic differentiate in MSCs in vitro and in vivo, which support to leukemia progression and disruption of normal hematopoiesis. Methods and Results: MSCs were prepared from bone marrow mononuclear cells isolated from normal human or CML- chronic phase (CCP) patients' BM and cultures in Cyagen Bone marrow culture medium at 37 °C, 5% CO2 incubator. In vitro, after stimulated with different concentrations of EphB4-Fc (0, 5, 8, 10 ug/ml) for 21 days, visualized by Alizarin Red staining, MSCs (CCP) produced maximum calcium nodules (P<0.05, n=3) in EphB4-Fc (8 ug/ml) group in contrast with other groups, accompanied by increased ephrinB1 and STAT3 phosphorylation. In vitro osteogenesis condition, after treatment with EphB4-Fc (0, 8 ug/ml) 14 days, MSCs (CCP) incubated with K562 cells. After 48 h, the IC50 (0.842±0.065, P<0.05, P<0.05 ANOVA, n=4) of K562 cells in MSCs+EphB4-Fc (8ug/ml) group increased, S phase cells percentage(56.6±4.01, P<0.05, P<0.01, ANOVA, n=4) increased and cells apoptosis rate(P<0.01, P<0.001, LSD, n=4) declined compared with K562 (control group) and K562+MSCs+EphB4-Fc (0 ug/ml). In vivo, K562-R, K562-R+MSCs (normal) (5:1), K562-R-EphB4-sh, K562-R-EphB4-sh+MSCs (normal) (5:1), MSCs (normal) cells were injected respectively into bone cavity of NOG rat (NOD/SCID/ɣ c-/-, n=12) rat and blank control group were also established. Examined peripheral blood in rats while hCD45+ cells > 1% is considered as leukemia model. K562-R+MSCs mice were earliest to establish leukemia model (31.75±1.26d) and had the shortest survival time(4.25±1.71d) than other groups. After treatment with IM, survival times of K562-R+MSCs mice were not significantly extended (4.7±3.055 d, pared-samples T test, P>0.05). In bone marrow of K562-R+MSCs mice, RUNX2 mRNA (0.654±0.0278; P < 0.001) over expressed in contrast to other groups. After treatment with IM, expression level of RUNX2 mRNA was significantly increased than non-treatment group. Among four leukemia groups of mice, expression levels VEGF mRNA in bone marrow were no significantly difference and there was no statistical difference existed in treatment group and non-treatment group. The same cells lines above were subcutaneously injected to establish subcutaneous transplantation tumor, respectively, in NOG rat (NOD/SCID/ɣ c-/-, n=8) rat. K562-R+MSCs tumors were earliest to appear (17.333±1.154 d) and had the biggest tumors volume (13116.27±165.502 mm3, P<0.001) compared to other groups. After mice treated by IM, compared with non-treatment group, K562-R+MSCs tumors had significantly increased in volume (14703.14±309.333mm3, pared-samples T test, P<0.01). VEGF mRNA (0.861±0.0648; P<0.01) in K562-R+MSCs tumor over express than other groups. After treatment, the expression level was no significantly declined (0.796±0.0688, P>0.05). The level expression of RUNX2 mRNA in four groups of subcutaneous transplantation tumors are low and had no statistical difference. Conclusion: Our experiments in vitro and in vivo illustrated that EphB4 molecule on leukemia cells may transform MSCs osteogenic differentiation to change characterize of Imatinib(IM)-resistant in CML through ephrinB1 and STAT3 phosphorylation. Disclosures Lin: Natural Science Foundation of China: Research Funding. Na:Natural Science Foundation of China: Research Funding.
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Luo, Hongyu, Zenghui Wu, Shijie Qi, Wei Jin, Bing Han та Jiangping Wu. "Ephrinb1 and Ephrinb2 Are Associated with Interleukin-7 Receptor α and Retard Its Internalization from the Cell Surface". Journal of Biological Chemistry 286, № 52 (2011): 44976–87. http://dx.doi.org/10.1074/jbc.m111.316414.
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Abéngozar, María Angeles, Sergio de Frutos, Sergio Ferreiro, et al. "Blocking ephrinB2 with highly specific antibodies inhibits angiogenesis, lymphangiogenesis, and tumor growth." Blood 119, no. 19 (2012): 4565–76. http://dx.doi.org/10.1182/blood-2011-09-380006.
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Abstract Membrane-anchored ephrinB2 and its receptor EphB4 are involved in the formation of blood and lymphatic vessels in normal and pathologic conditions. Eph/ephrin activation requires cell-cell interactions and leads to bidirectional signaling pathways in both ligand- and receptor-expressing cells. To investigate the functional consequences of blocking ephrinB2 activity, 2 highly specific human single-chain Fv (scFv) Ab fragments against ephrinB2 were generated and characterized. Both Ab fragments suppressed endothelial cell migration and tube formation in vitro in response to VEGF and provoked abnormal cell motility and actin cytoskeleton alterations in isolated endothelial cells. As only one of them (B11) competed for binding of ephrinB2 to EphB4, these data suggest an EphB-receptor–independent blocking mechanism. Anti-ephrinB2 therapy reduced VEGF-induced neovascularization in a mouse Matrigel plug assay. Moreover, systemic administration of ephrinB2-blocking Abs caused a drastic reduction in the number of blood and lymphatic vessels in xenografted mice and a concomitant reduction in tumor growth. Our results show for the first time that specific Ab-based ephrinB2 targeting may represent an effective therapeutic strategy to be used as an alternative or in combination with existing antiangiogenic drugs for treating patients with cancer and other angiogenesis-related diseases.
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Yamanda, Shinsuke, Satoru Ebihara, Masanori Asada, et al. "Role of ephrinB2 in nonproductive angiogenesis induced by Delta-like 4 blockade." Blood 113, no. 15 (2009): 3631–39. http://dx.doi.org/10.1182/blood-2008-07-170381.
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Abstract Delta-like 4 (DLL4) is one of the Notch ligands and plays an important role in vascular development. DLL4 blockade inhibits tumor growth by promoting nonproductive angiogenesis, which is characterized by an increase in vascular density and decrease in tissue perfusion. However, a detailed mechanism remains unclear. In this study, newly developed neutralizing antibodies against mouse and human DLL4 were used to investigate the possible involvement of VEGF-DLL4-ephrinB2 cascade in nonproductive angiogenesis caused by DLL4 blockade. DLL4 blockade and soluble ephrinB2 treatment suppressed tumor growth and induced nonproductive angiogenesis. DLL4 was expressed in subcutaneous tumors, and DLL4 blockade suppressed ephrinB2 expression in the tumors. DLL4 blockade significantly promoted human umbilical vein endothelial cell (HUVEC) proliferation in vitro, and the effect was additive to that of VEGF. Both DLL4 blockade and VEGF significantly increased cord length and branch points in a tubular formation assay. Expression of ephrinB2 in HUVECs was enhanced by VEGF alone, and the enhancement was inhibited by DLL4 blockade. Moreover, when we studied the effect of ephrinB2 RNA interference on HUVEC tubular formation, knockdown of ephrinB2 mimicked the effect of DLL4. These results suggest that ephrinB2 plays a crucial role in nonproductive angiogenesis caused by DLL4 blockade.
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Das, Amitava, Uday Shergill, Lokendra Thakur, et al. "Ephrin B2/EphB4 pathway in hepatic stellate cells stimulates Erk-dependent VEGF production and sinusoidal endothelial cell recruitment." American Journal of Physiology-Gastrointestinal and Liver Physiology 298, no. 6 (2010): G908—G915. http://dx.doi.org/10.1152/ajpgi.00510.2009.
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Chemotaxis signals between hepatic stellate cells (HSC) and sinusoidal endothelial cells (SEC) maintain hepatic vascular homeostasis and integrity and also regulate changes in sinusoidal structure in response to liver injury. Our prior studies have demonstrated that the bidirectional chemotactic signaling molecules EphrinB2 and EphB4 are expressed in HSC. The aim of our present study was to explore whether and how the EphrinB2/EphB4 system in HSC could promote SEC recruitment, which is essential for sinusoidal structure and remodeling. Stimulation of human HSC (hHSC) with chimeric agonists (2 μg/ml) of either EphrinB2 or EphB4 (EphrinB2 Fc or EphB4 Fc, respectively) significantly increased VEGF mRNA levels in hHSC as assessed by quantitative PCR, with respective small interfering RNAs for EphrinB2 and EphB4 inhibiting this increase ( P < 0.05, n = 3). EphrinB2 agonist-induced increase in VEGF mRNA levels in hHSC was associated with increased phosphorylation of Erk and was significantly blocked by U0126 (20 μM), an inhibitor of MEK, which is a kinase upstream from Erk ( P < 0.05, n = 3). The EphB4 agonist also significantly increased human VEGF promoter activity ( P < 0.05, n = 3) as assessed by promoter reporter luciferase assay in transfected LX2-HSC. This was associated with upregulation of the vasculoprotective transcription factor, Kruppel-like factor 2 (KLF2). In Boyden chamber assays, conditioned media from hHSC stimulated with agonists of EphrinB2 or EphB4 increased SEC chemotaxis in a VEGF-dependent manner, compared with control groups that included basal media with agonists of EphrinB2, EphB4, or HSC-conditioned media from HSC in absence of agonist stimulation ( P < 0.05, n = 3). EphB4 expression was detected in situ within liver sinusoidal vessels of rats after carbon tetrachloride-induced liver injury. In summary, activation of the EphrinB2/EphB4 signaling pathway in HSC promotes chemotaxis of SEC through a pathway that involves Erk, KLF2, and VEGF. These studies identify EphrinB2 or EphB4 as a key intermediary that links HSC signal transduction pathways with angiogenesis and sinusoidal remodeling.
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Su, Sheng-an, Du Yang, Yue Wu та ін. "EphrinB2 Regulates Cardiac Fibrosis Through Modulating the Interaction of Stat3 and TGF-β/Smad3 Signaling". Circulation Research 121, № 6 (2017): 617–27. http://dx.doi.org/10.1161/circresaha.117.311045.
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Rationale: Cardiac fibrosis is a common feature in left ventricular remodeling that leads to heart failure, regardless of the cause. EphrinB2 (erythropoietin-producing hepatoma interactor B2), a pivotal bidirectional signaling molecule ubiquitously expressed in mammals, is crucial in angiogenesis during development and disease progression. Recently, EphrinB2 was reported to protect kidneys from injury-induced fibrogenesis. However, its role in cardiac fibrosis remains to be clarified. Objective: We sought to determine the role of EphrinB2 in cardiac fibrosis and the underlying mechanisms during the pathological remodeling process. Methods and Results: EphrinB2 was highly expressed in the myocardium of patients with advanced heart failure, as well as in mouse models of myocardial infarction and cardiac hypertrophy induced by angiotensin II infusion, which was accompanied by myofibroblast activation and collagen fiber deposition. In contrast, intramyocardial injection of lentiviruses carrying EphrinB2-shRNA ameliorated cardiac fibrosis and improved cardiac function in mouse model of myocardial infarction. Furthermore, in vitro studies in cultured cardiac fibroblasts demonstrated that EphrinB2 promoted the differentiation of cardiac fibroblasts into myofibroblasts in normoxic and hypoxic conditions. Mechanistically, the profibrotic effect of EphrinB2 on cardiac fibroblast was determined via activating the Stat3 (signal transducer and activator of transcription 3) and TGF-β (transforming growth factor-β)/Smad3 (mothers against decapentaplegic homolog 3) signaling. We further determined that EphrinB2 modulated the interaction between Stat3 and Smad3 and identified that the MAD homology 2 domain of Smad3 and the coil–coil domain and DNA-binding domain of Stat3 mediated the interaction. Conclusions: This study uncovered a previously unrecognized profibrotic role of EphrinB2 in cardiac fibrosis, which is achieved through the interaction of Stat3 with TGF-β/Smad3 signaling, implying a promising therapeutic target in fibrotic diseases and heart failure.
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Ge, Yu-Wei, Kai Feng, Xiao-Liang Liu, et al. "The Recombinant Protein EphB4-Fc Changes the Ti Particle-Mediated Imbalance of OPG/RANKL via EphrinB2/EphB4 Signaling Pathway and Inhibits the Release of Proinflammatory Factors In Vivo." Oxidative Medicine and Cellular Longevity 2020 (June 6, 2020): 1–15. http://dx.doi.org/10.1155/2020/1404915.
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Aseptic loosening caused by wear particles is one of the common complications after total hip arthroplasty. We investigated the effect of the recombinant protein ephB4-Fc (erythropoietin-producing human hepatocellular receptor 4) on wear particle-mediated inflammatory response. In vitro, ephrinB2 expression was analyzed using siRNA-NFATc1 (nuclear factor of activated T-cells 1) and siRNA-c-Fos. Additionally, we used Tartrate-resistant acid phosphatase (TRAP) staining, bone pit resorption, Enzyme-linked immunosorbent assay (ELISA), as well as ephrinB2 overexpression and knockdown experiments to verify the effect of ephB4-Fc on osteoclast differentiation and function. In vivo, a mouse skull model was constructed to test whether the ephB4-Fc inhibits osteolysis and inhibits inflammation by micro-CT, H&E staining, immunohistochemistry, and immunofluorescence. The gene expression of ephrinB2 was regulated by c-Fos/NFATc1. Titanium wear particles activated this signaling pathway to the promoted expression of the ephrinB2 gene. However, ephrinB2 protein can be activated by osteoblast membrane receptor ephB4 to inhibit osteoclast differentiation. In in vivo experiments, we found that ephB4 could regulate Ti particle-mediated imbalance of OPG/RANKL, and the most important finding was that ephB4 relieved the release of proinflammatory factors. The ephB4-Fc inhibits wear particle-mediated osteolysis and inflammatory response through the ephrinB2/EphB4 bidirectional signaling pathway, and ephrinB2 ligand is expected to become a new clinical drug therapeutic target.
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Pennisi, Angela, Wen Ling, Xin Li, Jianmei Chen, Sharmin Khan, and Shmuel Yaccoby. "The EphrinB2/EphB4 Axis Is Dysregulated in Osteoprogenitors from Myeloma Patients and Its Activation by EphrinB2-Fc or EhpB4-Fc Affects Myeloma Bone Disease and Tumor Growth in Vivo." Blood 112, no. 11 (2008): 844. http://dx.doi.org/10.1182/blood.v112.11.844.844.
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Abstract Induction of osteolytic bone lesions in myeloma (MM) is caused by an uncoupling of osteoclastic bone resorption and osteoblastic bone formation. Recent studies indicate that in addition to role in cell adhesion, repulsion and neovascularization, bidirectional signaling between the cell surface molecules EphrinB2 and EphB4 also mediates the coupling between osteoblasts and osteoblasts. While mesenchymal stem cells (MSCs) and osteoblasts express the ligand EphrinB2 land its receptor, EphB4, osteoclasts and their precursors mainly express EphrinB2. Forward signaling in MSCs promotes osteogenic differentiation and reverse signaling in osteoclast precursors inhibits their differentiation. The aims of the study were to investigate whether the EphrinB2/Eph4 axis is dysregulated in MM osteoprogenitors and whether activation of this axis in myelomatous bone by EphrinB2-Fc or EphB4-Fc affects MM bone disease, angiogenesis and tumor growth. MSCs were generated from bone marrow of healthy donors (n=5) and patients with MM (n=13). Gene expression was determined by qRT-PCR. MSCs from MM patients had reduced expression of EphrinB2 (EFNB2) by 61±6% (p<0.02) and EphB4 by 60±10% (p<0.02) than expression levels of these molecules in MSCs from healthy donors. Expression of other EFN and EPH B genes were detected and similarly expressed in patients and donors MSCs. Differentiation of MSCs from MM patients into osteoblasts resulted in upregulation of EFNB2 and downregulation of EPHB4. MM cell lines and primary MM plasma cells expressed low to undetectable levels of this family of genes. We exploited our SCID-hu system for primary MM to study the consequences of activation of forward signaling by EphrinB2-Fc or reverse signaling by EphB4-Fc on MM-induced bone disease and MM growth. Twelve SCID-hu mice were engrafted with MM cells from a patient with active MM. Upon detection of MM growth (by human Ig ELISA) and bone disease (radiographically), hosts were locally treated with Fc (control), EphrinB2-Fc or EPHB4 (4 mice/group) for 4 weeks using Alzet pump that continually released 0.11 μg/hour of each compound. While in Fc-treated hosts BMD of the implanted bone was reduced by 8±3% from pretreatment levels, it was increased by EphrinB2-Fc and EPhB4-Fc by 15±8% (p<0.03 vs. Fc) and 2±1% (p<0.02 vs. Fc) from pretreatment levels, respectively. At experiment’s end levels of human Ig in mice sera were increased by 308±99% and 244±86% from pretreatment levels in Fc- and EphrinB2- Fc groups, respectively, while were reduced by 92±1% (p<0.02 vs. Fc) from pretreatment levels in EphB4-Fc group. In myelomatous bones, EphB4-Fc and EphrinB2-Fc increased the numbers of osteoblasts by >3 folds (p<0.004) while EphB4-Fc, but not EphrinB2-Fc, reduced osteoclast numbers by 5 folds (p<0.01 vs. Fc group). The numbers of CD34-reactive neovessels were reduced by 2 folds following treatment with EphB4-Fc (p<0.03) and were increased by 2.5 folds following treatment with EphrinB2-Fc (p<0.05). Our study suggests that downregulation of EphrinB2 and EhpB4 in MSCs from MM patients contributes to their impaired osteogenic differentiation and that treatment with EphrinB2-Fc or EphB4-Fc helps restore coupling of bone remodeling in myelomatous bones. The results also indicate that EphB4-Fc treatment is an effective approach to simultaneously inhibit MM and its associated bone disease.
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Gong, T., J. Xu, B. Heng, et al. "EphrinB2/EphB4 Signaling Regulates DPSCs to Induce Sprouting Angiogenesis of Endothelial Cells." Journal of Dental Research 98, no. 7 (2019): 803–12. http://dx.doi.org/10.1177/0022034519843886.
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Dental pulp stem cells (DPSCs) are capable of facilitating angiogenesis resembling pericytes when located adjacent to endothelial cells (ECs). Nevertheless, the precise mechanisms orchestrating their proangiogenic functions remain unclear. Using a 3-dimensional (3-D) fibrin gel model, we aimed to investigate whether EphrinB2/EphB4 signaling in DPSCs plays a role in supporting vascular morphogenesis mediated by ECs, together with the underlying mechanism involved. The EphrinB2/EphB4 signaling was inhibited either by a pharmacological inhibitor of EphB4 receptor or by knocking down the expressions of EphrinB2 and EphB4 using lentiviral small hairpin RNA (shRNA). DPSCs were either encapsulated in fibrin gel together with human umbilical vein endothelial cells (HUVECs) or cultured as a monolayer on top of HUVECs to investigate both paracrine and juxtacrine interactions simultaneously. Following 10 d of direct coculture, we found that pharmacological inhibition of EphrinB2/EphB4 signaling severely impaired vessel formation and laminin deposition. When directly cocultured with HUVECs, knockdown of EphrinB2 or EphB4 in DPSCs significantly inhibited endothelial sprouting, resulting in less capillary sprouts with reduced vessel length ( P < 0.05). By contrast, when DPSCs were not in direct contact with HUVECs, attenuation of EphrinB2 or EphB4 expression levels in DPSCs did not exert any significant effects on capillary morphogenesis. Noticeably, exogenous stimulation with soluble EphrinB2-Fc or EphB4-Fc (1 µg/mL) enhanced vascular endothelial growth factor (VEGF) secretion from DPSCs, thereby moderately promoting angiogenic cascades in the fibrin matrix. This study, for the first time, reveals a crucial role of EphrinB2/EphB4 signaling in regulating the capacity of DPSCs to induce sprouting angiogenesis. These findings advance our understanding of postnatal angiogenesis and may have future regenerative medicine applications.
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Cohen, Kenneth Stuart, Mina Jamali, and Elizabeth Hyjek. "Identification of ephrinB2 positive vessels in non-Hodgkin lymphoma subtypes." Journal of Clinical Oncology 31, no. 15_suppl (2013): e19542-e19542. http://dx.doi.org/10.1200/jco.2013.31.15_suppl.e19542.
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e19542 Background: Current anti-angiogenic therapies for tumors target signaling pathways such as VEGF. However, the role of alternative vascular pathways in tumor biology in general, and lymphoma biology specifically, are less well understood. Recently, the Eph receptor tyrosine kinase signaling pathway has emerged as a novel target for therapeutic inhibition. The EphB family member EphB4, and its reverse signaling ligand ephrinB2, are indispensible for developmental angiogenesis. Inhibition of ephrinB2 signaling results in impaired tumor growth in pre-clinical models. We therefore sought to determine if ephrinB2 is expressed in the microenvironment of human lymphomas and thereby represents a novel therapeutic target. Methods: We evaluated by immunohistochemistry on paraffin tissue sections expression of ephrinB2, CD34 (endothelial cells) and CD163 (macrophages) in LN biopsies from 12 cases of FL and 11 cases of DLBCL retrieved from the archives of the Department of Pathology at the University of Chicago (2000-2011). Eleven cases of follicular hyperplasia or quiescent LNs were used as controls (Cs). Slides were digitally scanned and examined both semi-quantitatively and by digital image analysis. Stained cells were quantified both in internal areas and at lymphoma-fat interfaces. Results: CD34+ microvessel densities were comparable between DLBCL and C groups but showed a significantly higher trend of interface angiogenic sprouts in FLs. Interface recruited CD163+ cell numbers were significantly higher in DLBCLs than in both FLs and Cs (p<0.0001). EphrinB2-expressing blood vessels were significantly increased in FLs but not in DLBCL. Conclusions: FLs demonstrate an increase in ephrinB2+/CD34+ vessels at the lymphoma-fat interface. In contrast, DLBCLs demonstrate no increase in ephrinB2+ vessels versus controls. However, DLBCLs were notable for increased recruitment of CD163+ macrophages at the tumor/host interface. These data represent the first analysis of ephrinB2 expression in human lymphomas and demonstrate heterogeneity between locations within a lymphoma and between histologic subtypes. Analysis of ephrinB2 in human lymphomas reveals marked heterogeneity in lymphoma microenvironmental domains.
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Su, Kaiyue, Ningning Lin, Shouqiang Xie, et al. "DNMT3A inhibits E2F1-induced arterial marker expression and impairs angiogenesis in human umbilical artery endothelial cells." Acta Biochimica et Biophysica Sinica 52, no. 11 (2020): 1236–46. http://dx.doi.org/10.1093/abbs/gmaa109.
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Abstract Arterial marker genes EphrinB2 and HEY2 are essential for cardiovascular development and postnatal neovascularization. Our previous study confirmed that E2F1 could activate the transcription of EphrinB2 and HEY2 in human mesenchymal stem cells; however, the detailed mechanism has not been resolved yet. In this study, we focused on the interaction between E2F1 and DNMT3A, a de novo DNA methyltransferase, on regulating the expression of EphrinB2 and HEY2, and explored the potential mechanisms. Gain- and loss-of-function experiments implicated the positive effect of E2F1 on the expression of EphrinB2 and HEY2 and tube formation in human umbilical artery endothelial cells. Accumulation of DNMT3A decreased the levels of EphrinB2 and HEY2, and impaired tube formation induced by E2F1, while inhibiting DNMT3A by RNA interference augmented their expression and angiogenesis in E2F1-trasfected cells. We then asked whether the low expressions of EphrinB2 and HEY2 induced by DNMT3A are related to the methylation status of their promoters. Surprisingly, the methylation status of the CpG islands in the promoter region was not significantly affected by overexpression of exogenous DNMT3A. Furthermore, the interaction between E2F1 and DNMT3A was confirmed by co-immunoprecipitation. DNMT3A could inhibit the transcription of EphrinB2 and HEY2 promoters by affecting the binding of E2F1 to its recognition sequences as revealed by luciferase reporter assay and chromatin immunoprecipitation. These results identified a novel mechanism underlying the cooperation of DNMT3A with E2F1 on regulating target gene expression, and revealed their roles in the angiogenic process.
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Yuan, Kuo, Tse-Ming Hong, Jeremy J. W. Chen, Wan Hua Tsai, and Ming T. Lin. "Syndecan-1 up-regulated by ephrinB2/EphB4 plays dual roles in inflammatory angiogenesis." Blood 104, no. 4 (2004): 1025–33. http://dx.doi.org/10.1182/blood-2003-09-3334.
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AbstractEphrinB2 and EphB4, its cognate receptor, are important in the vascular development of the mouse embryo. Their roles in human inflammatory angiogenesis, however, are not well understood. By examining hyperinflammatory lesions, we saw that ephrinB2 was predominantly expressed in macrophage-like cells and EphB4 in small venules. Because macrophages usually transmigrate through postcapillary venules during inflammation, we wanted to explore the downstream effects of EphB4 after binding to ephrinB2. By using cDNA microarray technique and following reverse transcriptase–polymerase chain reaction (RT-PCR), we found that syntenin and syndecan-1 were up-regulated in EphB4-positive endothelial cells dose dependently and time dependently after stimulation with preclustered ephrinB2. In vitro, ephrinB2 suppressed the angiogenic effects of basic fibroblast growth factor (bFGF) on EphB4-positive endothelial cells, partially due to syndecan-1's competition with fibroblast growth factor receptor (FGFR) for bFGF. However, ephrinB2 exhibited angiogenic effects in vivo, possibly due to an inflammation-associated enzyme—heparanase. The enzymes could convert the inhibitory effect of ephrinB2 on EphB4-positive endothelial cells to an activating effect by removing poorly sulfated side chains of up-regulated syndecan-1 ectodomain. Depending on the presence of heparanases, the roles of syndecan-1 may be opposite in different physiological settings.
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Groeger, Gillian, and Catherine D. Nobes. "Co-operative Cdc42 and Rho signalling mediates ephrinB-triggered endothelial cell retraction." Biochemical Journal 404, no. 1 (2007): 23–29. http://dx.doi.org/10.1042/bj20070146.
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Cell repulsion responses to Eph receptor activation are linked to rapid actin cytoskeletal reorganizations, which in turn are partially mediated by Rho–ROCK (Rho kinase) signalling, driving actomyosin contractility. In the present study, we show that Rho alone is not sufficient for this repulsion response. Rather, Cdc42 (cell division cycle 42) and its effector MRCK (myotonic dystrophy kinase-related Cdc42-binding kinase) are also critical for ephrinB-induced cell retraction. Stimulation of endothelial cells with ephrinB2 triggers rapid, but transient, cell retraction. We show that, although membrane retraction is fully blocked by blebbistatin (a myosin-II ATPase inhibitor), it is only partially blocked by inhibiting Rho–ROCK signalling, suggesting that there is ROCK-independent signalling to actomyosin contractility downstream of EphBs. We find that a combination of either Cdc42 or MRCK inhibition with ROCK inhibition completely abolishes the repulsion response. Additionally, endocytosis of ephrin–Eph complexes is not required for initial cell retraction, but is essential for subsequent Rac-mediated re-spreading of cells. Our data reveal a complex interplay of Rho, Rac and Cdc42 in the process of EphB-mediated cell retraction–recovery responses.
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Prospéri, Marie-Thérèse, Priscilla Lépine, Florent Dingli, et al. "Myosin 1b functions as an effector of EphB signaling to control cell repulsion." Journal of Cell Biology 210, no. 2 (2015): 347–61. http://dx.doi.org/10.1083/jcb.201501018.
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Eph receptors and their membrane-tethered ligands, the ephrins, have important functions in embryo morphogenesis and in adult tissue homeostasis. Eph/ephrin signaling is essential for cell segregation and cell repulsion. This process is accompanied by morphological changes and actin remodeling that drives cell segregation and tissue patterning. The actin cortex must be mechanically coupled to the plasma membrane to orchestrate the cell morphology changes. Here, we demonstrate that myosin 1b that can mechanically link the membrane to the actin cytoskeleton interacts with EphB2 receptors via its tail and is tyrosine phosphorylated on its tail in an EphB2-dependent manner. Myosin 1b regulates the redistribution of myosin II in actomyosin fibers and the formation of filopodia at the interface of ephrinB1 and EphB2 cells, which are two processes mediated by EphB2 signaling that contribute to cell repulsion. Together, our results provide the first evidence that a myosin 1 functions as an effector of EphB2/ephrinB signaling, controls cell morphology, and thereby cell repulsion.
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Obi, Syotaro, Kimiko Yamamoto, Nobutaka Shimizu, et al. "Fluid shear stress induces arterial differentiation of endothelial progenitor cells." Journal of Applied Physiology 106, no. 1 (2009): 203–11. http://dx.doi.org/10.1152/japplphysiol.00197.2008.
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Endothelial progenitor cells (EPCs) are mobilized from bone marrow to peripheral blood and contribute to angiogenesis in tissues. In the process, EPCs are exposed to the shear stress generated by blood flow and tissue fluid flow. Our previous study showed that shear stress promotes differentiation of EPCs into mature endothelial cells. In this study, we investigated whether EPCs differentiate into arterial or venous endothelial cells in response to shear stress. When cultured EPCs derived from human peripheral blood were exposed to controlled levels of shear stress in a flow-loading device, the mRNA levels of the arterial endothelial cell markers ephrinB2, Notch1/3, Hey1/2, and activin receptor-like kinase 1 increased, but the mRNA levels of the venous endothelial cell markers EphB4 and neuropilin-2 decreased. Both the ephrinB2 increase and the EphB4 decrease were shear stress dependent rather than shear rate dependent. EphrinB2 protein was increased in shear-stressed EPCs, and the increase in ephrinB2 expression was due to activated transcription and not mRNA stabilization. Deletion analysis of the ephrinB2 promoter indicated that the cis-element (shear stress response element) is present within 106 bp 5′ upstream from the transcription initiation site. This region contains the Sp1 consensus sequence, and a mutation in its sequence decreased the basal level of transcription and abolished shear stress-induced ephrinB2 transcription. Electrophoretic mobility shift assays and chromatin immunoprecipitation assays showed that shear stress markedly increased binding of Sp1 to its consensus sequence. These results indicate that shear stress induces differentiation of EPCs into arterial endothelial cells by increasing ephrinB2 expression in EPCs through Sp1 activation.
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Gervais, Manon, Gwenaël Labouèbe, Alexandre Picard, Bernard Thorens, and Sophie Croizier. "EphrinB1 modulates glutamatergic inputs into POMC-expressing progenitors and controls glucose homeostasis." PLOS Biology 18, no. 11 (2020): e3000680. http://dx.doi.org/10.1371/journal.pbio.3000680.
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Proopiomelanocortin (POMC) neurons are major regulators of energy balance and glucose homeostasis. In addition to being regulated by hormones and nutrients, POMC neurons are controlled by glutamatergic input originating from multiple brain regions. However, the factors involved in the formation of glutamatergic inputs and how they contribute to bodily functions remain largely unknown. Here, we show that during the development of glutamatergic inputs, POMC neurons exhibit enriched expression of the Efnb1 (EphrinB1) and Efnb2 (EphrinB2) genes, which are known to control excitatory synapse formation. In vivo loss of Efnb1 in POMC-expressing progenitors decreases the amount of glutamatergic inputs, associated with a reduced number of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptor subunits and excitability of these cells. We found that mice lacking Efnb1 in POMC-expressing progenitors display impaired glucose tolerance due to blunted vagus nerve activity and decreased insulin secretion. However, despite reduced excitatory inputs, mice lacking Efnb2 in POMC-expressing progenitors showed no deregulation of insulin secretion and only mild alterations in feeding behavior and gluconeogenesis. Collectively, our data demonstrate the role of ephrins in controlling excitatory input amount into POMC-expressing progenitors and show an isotype-specific role of ephrins on the regulation of glucose homeostasis and feeding.
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Sun, Chen-Li, Cheng-Wen Li, Nong He, et al. "Blockade of Erythropoietin-Producing Human Hepatocellular Carcinoma Receptor B1 in Spinal Dorsal Horn Alleviates Visceral Pain in Rats." Pain Research and Management 2021 (April 7, 2021): 1–9. http://dx.doi.org/10.1155/2021/7582494.
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Objective. This experiment was designed to determine whether erythropoietin-producing human hepatocellular carcinoma (Eph) receptors were involved in the development of visceral pain. Methods. Adult male Sprague-Dawley rats were randomly divided into three groups receiving different treatments (n = 16 per group): intracolonic vehicle (control group), intracolonic 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) (TNBS group), and intracolonic TNBS and intrathecal EphB1 receptor blocking reagent (TNBS + EphB2-Fc group). Visceral hyperalgesia was evaluated with quantification of visceral pain threshold induced by colorectal distention. The spinal expressions of EphB1 and ephrinB2 and levels of their phosphorylated forms (p-EphB1 and p-ephrinB2) were assessed by Western blotting and immunohistochemistry. Results. The TNBS-treated rats developed significant visceral hyperalgesia. The spinal expressions of EphB1, p-EphB1, ephrinB2, and p-ephrinB2 were significantly increased in the TNBS group compared with the control group, but visceral hyperalgesia and elevation of spinal EphB1 and p-EphB1 expressions were evidently alleviated by intrathecal administration of EphB2-Fc in the TNBS + EphB2-Fc group. The number of EphB1- and p-EphB1-immunopositive cells, the average optical (AO) value of EphB1, and its phosphorylated form in the spinal dorsal horn were significantly increased in the TNBS group than in the control group, but they were obviously reduced by intrathecal administration of EphB2-Fc. There were no significant differences in the number of ephrinB2- and p-ephrinB2-immunopositive cells and the AO value of ephrinB2 and its phosphorylated form between the TNBS and TNBS + EphB2-Fc groups. Conclusion. EphB1 receptors in the spinal dorsal horn play a pivotal role in the development of visceral pain and may be considered as a potential target for the treatment of visceral pain.
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Ghori, Adnan, Florian B. Freimann, Melina Nieminen-Kelhä, et al. "EphrinB2 Activation Enhances Vascular Repair Mechanisms and Reduces Brain Swelling After Mild Cerebral Ischemia." Arteriosclerosis, Thrombosis, and Vascular Biology 37, no. 5 (2017): 867–78. http://dx.doi.org/10.1161/atvbaha.116.308620.
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Objective— Cerebral edema caused by the disruption of the blood–brain barrier is a major complication after stroke. Therefore, strategies to accelerate and enhance neurovascular recovery after stroke are of prime interest. Our main aim was to study the role of ephrinB2/EphB4 signaling in mediating the vascular repair and in blood–brain barrier restoration after mild cerebral ischemia occlusion/reperfusion. Approach and Results— Here, we show that the guidance molecule ephrinB2 plays a key role in neurovascular protection and blood–brain barrier restoration after stroke. In a focal stroke model, we characterize the stroke-induced damage to cerebral blood vessels and their subsequent endogenous repair on a cellular, molecular, and functional level. EphrinB2 and its tyrosine kinase receptor EphB4 are upregulated early after stroke by endothelial cells and perivascular support cells, in parallel to their reassembly during neurovascular recovery. Using both retroviral and pharmacological approaches, we show that the inhibition of ephrinB2/EphB4 signaling suppresses post-middle cerebral artery occlusion neurovascular repair mechanisms resulting in an aggravation of brain swelling. In contrast, the activation of ephrinB2 after brain ischemia leads to an increased pericyte recruitment and increased endothelial–pericyte interaction, resulting in an accelerated neurovascular repair after ischemia. Conclusions— We show that reducing swelling could result in improved outcome because of reduction in damaged brain tissue. We also identify a novel role for ephrinB2/EphB4 signaling in the maintenance of the neurovascular homeostasis and provide a novel therapeutic approach in reducing brain swelling after stroke.
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Kertesz, Nathalie, Valery Krasnoperov, Ramachandra Reddy, et al. "The soluble extracellular domain of EphB4 (sEphB4) antagonizes EphB4-EphrinB2 interaction, modulates angiogenesis, and inhibits tumor growth." Blood 107, no. 6 (2006): 2330–38. http://dx.doi.org/10.1182/blood-2005-04-1655.
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AbstractThe receptor tyrosine kinase EphB4 and its ligand EphrinB2 play a crucial role in vascular development during embryogenesis. The soluble monomeric derivative of the extracellular domain of EphB4 (sEphB4) was designed as an antagonist of EphB4/EphrinB2 signaling. sEphB4 blocks activation of EphB4 and EphrinB2; suppresses endothelial cell migration, adhesion, and tube formation in vitro; and inhibits the angiogenic effects of various growth factors (VEGF and bFGF) in vivo. sEphB4 also inhibits tumor growth in murine tumor xenograft models. sEphB4 is thus a therapeutic candidate for vascular proliferative diseases and cancer.
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Ashley, George R., O. Cathal Grace, Griet Vanpoucke, and Axel A. Thomson. "Identification of EphrinB1 expression in prostatic mesenchyme and a role for EphB–EphrinB signalling in prostate development." Differentiation 80, no. 2-3 (2010): 89–98. http://dx.doi.org/10.1016/j.diff.2010.06.003.
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Liu, Rui, Runze Yu, Yuxin Cui, Mengying Fan, Bo Wang, and Yanmin Zhang. "Inhibitory effect of taspine derivative TAD1822-7 on tumor cell growth and angiogenesis via suppression of EphrinB2 and related signaling pathways." Acta Pharmaceutica 69, no. 3 (2019): 423–31. http://dx.doi.org/10.2478/acph-2019-0021.
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Abstract The aim of this study was to investigate the inhibitory effect of TAD1822-7, a synthesized taspine derivative, on cancer through its effects on tumor cell growth and angiogenesis via suppression of EphrinB2. The obtained data showed that TAD1822-7 decreased Bel-7402 cell viability and colony formation ability and suppressed cell migration. TAD1822-7 effectively inhibited blood vessel formation in an aortic ring assay to examine angiogenesis. Moreover, it also down regulated the expression of VEGFR2, VEGFR3, CD34, PLCγ, Akt, MMP2, MMP9, and CXCR4, and suppressed the expression of EphrinB2 and its PDZ protein, PICK1, in Bel-7402 cells. These results indicate that TAD1822-7 is a potential anti-angiogenic agent that can inhibit the viability and migration of Bel-7402 cells via suppression of EphrinB2 and the related signaling pathways.
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Barneh, Farnaz, Mona Moshayedi, Hamid Mirmohammadsadeghi, Shaghayegh Haghjooy-Javanmard, Ali Mohammad Sabzghabaee, and Shirinsadat Badri. "EphB4 Tyrosine Kinase Stimulation Inhibits Growth of MDA-MB-231 Breast Cancer Cells in a Dose and Time Dependent Manner." Disease Markers 35 (2013): 933–38. http://dx.doi.org/10.1155/2013/857895.
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Background. EphB4 receptor tyrosine kinase is of diagnostic and therapeutic value due to its overexpression in breast tumors. Dual functions of tumor promotion and suppression have been reported for this receptor based on presence or absence of its ligand. To elucidate such discrepancy, we aimed to determine the effect of time- and dose-dependent stimulation of EphB4 on viability and invasion of breast cancer cells via recombinant ephrinB2-Fc.Methods. Cells were seeded into multiwell plates and were stimulated by various concentrations of preclustered ephrinB2-Fc. Cell viability was measured on days 3 and 6 following treatment using alamar-blue when cells were in different states of confluence.Results. Stimulation of cells with ephrinB2 did not pose any significant effect on cell viability before reaching confluence, while inhibition of cell growth was detected after 6 days when cells were in postconfluent state following a dose-dependent manner. EphrinB2 treatment did not affect tubular formation and invasion on matrigel.Conclusion. This study showed that EphB4 can differentially inhibit cells at post confluent state and that presence of ligand manifests growth-inhibitory properties of EphB4 receptor. It is concluded that growth inhibition has occurred possibly due to long treatment with ligand, a process which leads to receptor downregulation.
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Randolph, Matthew E., Megan M. Cleary, Zia Bajwa, et al. "EphB4/EphrinB2 therapeutics in Rhabdomyosarcoma." PLOS ONE 12, no. 8 (2017): e0183161. http://dx.doi.org/10.1371/journal.pone.0183161.
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Thomas, Jacob Stephen, Heinz-Josef Lenz, Syma Iqbal, et al. "A first-in-human phase I study of sEphB4-HSA (sEphB4) with expansion in hepatocellular (HCC) and cholangiocarcinoma (CCA)." Journal of Clinical Oncology 36, no. 4_suppl (2018): 285. http://dx.doi.org/10.1200/jco.2018.36.4_suppl.285.
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285 Background: EphrinB4, a receptor kinase, is associated with stage and survival in epithelial cancers. sEphB4 is a fusion protein of soluble EphB4 and albumin. sEphB4 binds to EphrinB2, a protein expressed in tumor cells and vessels, and blocks bidirectional signaling. sEphB4 downregulates the PI3K/AKT/mTOR pathway, inhibits angiogenesis, and promotes recruitment of cytotoxic T cells and NK cells. MTD was not reached during dose escalation. The RP2D was 10 mg/Kg weekly. Here we report the results of the expansion cohorts in HCC and CCA. Methods: The study evaluated the safety, PK, PD and efficacy of sEphB4 in pts with advanced solid tumors in a 3+3 design with expansion at the RP2D in 7 solid tumors including HCC and CCA. Pts received sEphB4 10 mg/kg IV weekly in 28-day cycles. Eligibility included ECOG 0-1, Child-Pugh score ≤ 7, platelets > 50,000, AST/ALT ≤ 3xULN, serum bilirubin ≤ 1.5mg/dL and no uncontrolled hypertension. Results: 29 pts were treated: 17 HCC and 12 biliary cancers (8 CCA and 4 gallbladder). Median age was 63(25-77). ECOG PS was 1 in 76%. Median prior regimens were 1 (0-6) for HCC and 2 (1-3) for biliary cancers. 2 HCC pts had prior liver transplantation, 9 had prior anti PD-1 therapy and 2 had Child-Pugh score of B7. Median number of cycles was 4 (1-21) in HCC and 2 (1-17) in CCA. No grade 4 treatment-related adverse events (TRAE). Grade 3 TRAE were hypertension (41%) and fatigue, headache, neutropenia all in 1 pt each. Disease progression was the most common reason for treatment discontinuation. Median PFS in months was 5.0 (3.0-7.5) in HCC and 3.0 (1.6-9.2) in CCA. Median OS in months was 27.1 (4.4-27.1) in HCC and 12.0 (3.0-28.2) in CCA. Disease control rate was 70% in HCC and 42% in CCA including 1 PR in HCC. In HCC pts, 5/5 with 3+ EphrinB2 expression in tumor had PR or SD ≥ 6 months. Only 1/4 pts with ≤2+ expression had SD ≥ 4 months. 3/3 pts with HCC showed an increase in T cell infiltration, and decrease in pS6 (PI3K pathway activity) on post-treatment biopsy. Conclusions: sEphB4 has a manageable safety profile with preliminary evidence of anti-tumor activity in pretreated pts with HCC and biliary cancers. Several trials combining sEphB4-HSA with cytotoxic chemotherapy or immunotherapy are ongoing. Clinical trial information: NCT01642342.
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Salvucci, Ombretta, Dragan Maric, Matina Economopoulou, et al. "EphrinB reverse signaling contributes to endothelial and mural cell assembly into vascular structures." Blood 114, no. 8 (2009): 1707–16. http://dx.doi.org/10.1182/blood-2008-12-192294.
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Abstract EphrinB transmembrane ligands and their cognate EphB receptor tyrosine kinases regulate vascular development through bidirectional cell-to-cell signaling, but little is known about the role of EphrinB during postnatal vascular remodeling. We report that EphrinB is a critical mediator of postnatal pericyte-to-endothelial cell assembly into vascular structures. This function is dependent upon extracellular matrix-supported cell-to-cell contact, engagement of EphrinB by EphB receptors expressed on another cell, and Src-dependent phosphorylation of the intracytoplasmic domain of EphrinB. Phosphorylated EphrinB marks angiogenic blood vessels in the developing and hypoxic retina, the wounded skin, and tumor tissue, and is detected at contact points between endothelial cells and pericytes. Furthermore, inhibition ofEphrinB activity prevents proper assembly of pericytes and endothelial cells into vascular structures. These results reveal a role for EphrinB signaling in orchestrating pericyte/endothelial cell assembly, and suggest that therapeutic targeting of EphrinB may prove useful for disrupting angiogenesis when it contributes to disease.
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Prévost, Nicolas, Donna S. Woulfe, Massimiliano Tognolini, et al. "Signaling by ephrinB1 and Eph kinases in platelets promotes Rap1 activation, platelet adhesion, and aggregation via effector pathways that do not require phosphorylation of ephrinB1." Blood 103, no. 4 (2004): 1348–55. http://dx.doi.org/10.1182/blood-2003-06-1781.
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Abstract We have previously shown that platelets express 2 receptor tyrosine kinases, EphA4 and EphB1, and the Eph kinase ligand, ephrinB1, and proposed that transcellular Eph/ephrin interactions made possible by the onset of platelet aggregation promote the further growth and stability of the hemostatic plug. The present study examines how this might occur. The results show that clustering of either ephrinB1 or EphA4 causes platelets to adhere to immobilized fibrinogen via αIIbβ3. Adhesion occurs more slowly than with adenosine diphosphate (ADP) and requires phosphatidylinositol 3 (PI3)–kinase and protein kinase C activity but not ephrinB1 phosphorylation. By itself, Eph and ephrin signaling is insufficient to cause aggregation or the binding of soluble fibrinogen, but it can potentiate aggregation initiated by a Ca++ ionophore or by agonists for thrombin and thromboxane receptors. It also enhances Rap1 activation without requiring ADP secretion, ephrinB1 phosphorylation, or the activation of PI3-kinase and Src. From this we conclude that (1) Eph/ephrin signaling enhances the ability of platelet agonists to cause aggregation provided that those agonists can increase cytosolic Ca++; (2) this is accomplished in part by activating Rap1; and (3) these effects require oligomerization of ephrinB1 but not phosphotyrosine-based interactions with the ephrinB1 cytoplasmic domain.
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Scehnet, Jeffrey S., Eric J. Ley, Valery Krasnoperov, et al. "The role of Ephs, Ephrins, and growth factors in Kaposi sarcoma and implications of EphrinB2 blockade." Blood 113, no. 1 (2009): 254–63. http://dx.doi.org/10.1182/blood-2008-02-140020.
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Abstract Kaposi sarcoma (KS) is associated with human herpesvirus (HHV)-8 and is dependent on the induction of vascular endothelial growth factors (VEGFs). VEGF regulates genes that provide arterial or venous identity to endothelial cells, such as the induction of EphrinB2, which phenotypically defines arterial endothelial cells and pericytes, and represses EphB4, which defines venous endothelial cells. We conducted a comprehensive analysis of the Eph receptor tyrosine kinases to determine which members are expressed and therefore contribute to KS pathogenesis. We demonstrated limited Eph/Ephrin expression; notably, the only ligand highly expressed is EphrinB2. We next studied the biologic effects of blocking EphrinB2 using the extracellular domain of EphB4 fused with human serum albumin (sEphB4-HSA). sEphB4-HSA inhibited migration and invasion of the KS cells in vitro in response to various growth factors. Finally, we determined the biologic effects of combining sEphB4-HSA and an antibody to VEGF. sEphB4-HSA was more active than the VEGF antibody, and combination of the 2 had at least additive activity. sEphB4-HSA reduced blood vessel density, pericyte recruitment, vessel perfusion, and increased hypoxia, with an associated increase in VEGF and DLL4 expression. The combination of sEphB4-HSA and VEGF antibody is a rational treatment combination for further investigation.