Dissertations / Theses on the topic 'Receptores EP'

O glioblastoma (GBM) é o tumor mais frequente do sistema nervoso central com um alto grau de malignidade e um prognóstico desfavorável. Apesar dos avanços nas técnicas cirúrgicas e de radioterapia e/ou quimioterapia, não há tratamento eficiente disponível para o GBM. Os prostanoide são derivados do ácido araquidônico e estão envolvidas com vários processos do desenvolvimento e progressão do câncer. O objetivo deste estudo foi analisar in vitro o perfil de diferentes prostanoides nas linhagens de GBM. Além de analisar o papel dos prostanoides e dos receptores na migração celular de GBM. Os resultados demostraram um perfil dos prostanoides da série 2 diferente entre as linhagens, além da expressão dos genes envolvidos na biossíntese de PGE2. Nos ensaios de migração os dados demostraram que os tratamentos realizados com os prostanoides exógenos aumentaram a migração celular e os tratamentos com os antagonistas de EP2 e EP4 diminuiram a migração. Em conjunto esses resultados, demonstram o papel importante dos prostanoides, especialmente PGE2, no processo de migração das células de GBM.<br>Glioblastoma (GBM) is the most common tumor of the central nervous system with a high degree of malignancy and poor prognosis. Despite advances in surgical techniques and radiation therapy and/or chemotherapy, there is no effective treatment available for GBM. The prostanoid are derived from arachidonic acid and are involved in many processes of development and progression of cancer. The aim of this study was to analyze in vitro profile of different prostanoids in the lines of GBM. In addition to analyzing the role of prostanoids and receptors on the cell migration of GBM. The results showed a profile of series 2 prostanoids the different between the cell lines, in addition to expression of genes involved in the biosynthesis of PGE2. In migration testing data showed that the treatments performed with exogenous prostanoids increased cell migration and treatment with antagonists of EP2 and EP4 decreased migration. Together these results demonstrate the important role of prostanoids, especially PGE2, in the migration process of the GBM cells.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Epilepsy is one of the most common neurologic disorders. It has been suggested that seizures may be facilitaded by inflammation. PGE2 is one of the most important inflammatory mediators, and facilitates pentylenetetrazol (PTZ)-induced seizures by stimulating EP1 and EP3 receptors. However, up to the present moment, no study has investigated whether EP1 and EP3 receptors blocking attenuate seizures induced by convulsants other than PTZ. It is also unknown whether Na+,K+-ATPase activity alterations are involved in such an effect. Therefore, in the current study we investigated whether EP1 and EP3 ligands (agonists and antagonists) modulate PTZ- and kainic acid (KA)-induced seizures, and whether alterations in Na+,K+-ATPase activity mediate such a protective effect, in mice. EP1 and EP3 antagonists (ONO-8713 and ONO-AE3-240, respectively, 10 Og/kg, s.c.) attenuated PTZ (60 mg/kg, i.p.)- and KA (20 mg/kg, i.p.)-induced seizures. The respective agonists (ONO-DI-004 and ONO-AE-248, 10 Og/kg, s.c.) facilitated seizures in both acute models, and at noneffective doses, prevented the protective effects of the antagonists. Animals injected with PTZ presented decreased Na+,K+-ATPase activity in the cerebral cortex and hippocampus. On the other hand, animals injected with KA presented increased Na+,K+-ATPase activity in the same cerebral structures at the end of the experiment. These divergent findings suggest that alterations in Na+,K+-ATPase activity in both acute models depends on the convulsant agent used and make difficult to establish a relationship between Na+,K+-ATPase activity and seizure development. Moreover, EP1 and EP3 antagonists administration abolished Na+,K+- ATPase activity alterations induced by PTZ and KA, in such a way that these alterations seem to be related more to the presence of ictal phenomenon itself than to the seizure induction mechanisms. Notwithstanding, the currrent results clearly show that EP1 and EP3 receptors might constitute novel targets for anticonvulsants development, since EP1 and EP3 decreased seizures, regardless of the convulsant agent used.<br>A epilepsia é uma das disfunções neurológicas mais comuns. Tem sido sugerido que as crises epilépticas podem ser facilitadas pela ocorrência de inflamação. A PGE2 é um dos mediadores inflamatórios mais importantes que, agindo por meio dos receptores EP1 e EP3, facilita as convulsões induzidas por pentilenotetrazol (PTZ). Contudo, até a presente data, nenhum estudo investigou, de maneira sistêmica, se a ativação ou bloqueio de receptores EP1 e EP3 facilitam as convulsões induzidas por outros agentes; tampouco se alterações na atividade da Na+,K+-ATPase estão envolvidas nesse efeito. Assim, no presente estudo, investigamos se ligantes (agonistas e antagonistas) de receptores EP1 e EP3 modificam as crises induzidas por PTZ e ácido caínico (KA), e se tais efeitos estão associados a alterações na atividade da enzima Na+,K+-ATPase, em camundongos. Os antagonistas EP1 e EP3 (ONO-8713 e ONO-AE3-240, respectivamente, 10 Og/Kg, s.c.) atenuaram as convulsões induzidas por PTZ (60 mg/Kg, i.p.) e KA (20 mg/Kg). Os seus respectivos agonistas (ONO-DI-004 e ONO-AE-248 de 10 Og/Kg, s.c.) facilitaram as convulsões em ambos modelos agudos de crises epilépticas e, em doses não efetivas para gerar crises, preveniram os efeitos dos antagonistas. Os animais submetidos à administração de PTZ apresentaram, ao final do experimento, a atividade Na+,K+-ATPásica diminuída no córtex cerebral e hipocampo. Por outro lado, animais tratados com KA apresentaram um aumento na atividade Na+,K+-ATPásica nestas mesmas estruturas, que se correlacionou positivamente com a vigência de status epilepticus no momento do sacrifício. Os achados divergentes no que diz respeito à alteração da atividade da Na+,K+-ATPase nos dois modelos de crises agudas sugere que tais alterações estejam relacionadas ao tipo de agente convulsivante utilizado, e dificultam estabelecer, de forma inequívoca, uma relação entre atividade desta ATPase e sensibilidade à crises agudas. Ademais, a administração de antagonistas EP1 e EP3 aboliu as alterações da atividade da Na+,K+-ATPase induzidas tanto por PTZ como por KA, de tal forma que estas parecem estar mais associadas com o fenômeno ictal em si, do que com os mecanismos de indução da crise. Contudo, os resultados mostram de forma clara que os receptores EP1 e EP3 podem se constituir possíveis novos alvos para o desenvolvimento de drogas antiepilépticas, pois antagonistas EP1 e EP3 diminuíram as crises, independente do agente convulsivante utilizado.

The fever response, besides being part of host defense response to infection or inflammation, is associated with discomfort and anxiety and may constitute a risk for febrile seizures in children. Therefore, antipyretic therapy is routinely prescribed for febrile patients. The animal models of fever using the systemic injection of lipopolysaccharide (LPS) and Baker yeast, described in the literature, are suitable for screening of novel antipyretics, but they do not provide information regarding the mechanism of action of these compounds. Therefore, the present study aimed to describe and validate a model of fever induction by prostaglandin (PG) E2, the final mediator of febrile response in the central nervous system, in young male Wistar rats (25-30 days of age). In this protocol, PGE2 was injected intrathecally without implantation of cannula. Rectal temperature (TR) was recorded every thirty minutes for three hours after PGE2 injection (08:00 11:00 h). The intrathecal (i.t.) injection of PGE2 10 ηg in 100 μL/animal induced fever in the animals, which was prevented by administration of EP1 and EP3 receptors antagonists, but did not by antagonist of EP4 receptor. In addition, the classic antipyretics dipyrone and acetaminophen, at doses that had no effect per se on TR of animals, did not revert the fever induced by i.t. injection of PGE2. This model seems suitable to investigate whether the action of antipyretics occurs upstream or downstream the prostaglandin coupling in EP receptors. In addition, this protocol is advantageous from the technical, ethical and economical point of view compared to others PGE2-induced fever protocols described in the literature, because trepanation for cannula implantation is not required, reducing the inflammatory response, animals suffering and experimental costs.<br>A febre, apesar de fazer parte da resposta de defesa do hospedeiro à infecção ou inflamação, está associada com desconforto e ansiedade, além de representar um risco iminente de convulsões febris em crianças. Por isso, terapia antipirética é rotineiramente prescrita a pacientes febris. Os modelos animais de febre empregando a injeção sistêmica de lipopolissacarídeo (LPS) e fermento de padeiro, descritos na literatura, são úteis para a triagem de novos antipiréticos, mas não fornecem informações a respeito do mecanismo de ação desses compostos. Diante disso, o presente estudo objetivou padronizar e validar um modelo de indução de febre por prostaglandina (PG) E2, o mediador final da resposta febril no sistema nervoso central, em ratos machos jovens da raça Wistar (25-30 dias). Neste protocolo, a PGE2 foi injetada pela via intratecal (i.t.), não necessitando a implantação de cânula. A temperatura retal (TR) foi registrada a cada trinta minutos durante três horas após a injeção da PGE2 (08:00-11:00 h). A injeção i.t. de PGE2 10 ηg em 100 μL/animal induziu febre nos animais, a qual foi prevenida pela administração de antagonistas dos receptores EP1 e EP3, mas não por antagonista do receptor EP4. Além disso, os antipiréticos clássicos dipirona e paracetamol, em doses que não tiveram efeito per se na TR dos animais, não reverteram a febre induzida por PGE2 i.t. Este modelo parece útil para investigar se a ação dos antipiréticos ocorre antes ou depois da ligação da PGE2 em seus receptores EP. Além disso, este protocolo é vantajoso do ponto de vista técnico, ético e econômico em relação aos outros protocolos de indução de febre por PGE2 descritos na literatura, porque a trepanação para implantação de cânula não é necessária, reduzindo a resposta inflamatória, o sofrimento dos animais e os custos experimentais.

Prostaglandin E2 (PGE2) interacts with four E-Prostanoid (EP) receptor subtypes---designated EP1--4 . In glomerulonephritis (GN), a renal inflammatory disease, inhibition of enhanced renal PGE2 synthesis by nonsteroidal-anti-inflammatory drugs (NSAIDs), results in both beneficial anti-proteinuric effects and deleterious side effects on renal blood flow (RBF) and Na+ homeostasis, implying that one or more EP subtypes may mediate these actions. We set out to investigate the role of the EP1 receptor in GN since it localizes to the collecting duct, where it may regulate Na+ homeostasis, in podocytes and mesangial cells, where it could alter the permeability of the glomerulus, and in arterioles, where EP, receptors may induce vasoconstriction thereby reducing RBF. A mouse model of GN was induced in wildtype (wt) and EP1-/- mice using an anti-rat-glomerular basement membrane (anti-GBM) antibody. Proteinuria was similar in GN wt and GN EP1-/- groups thereby negating a role for this subtype in modulating filtration barrier permeability. (Abstract shortened by UMI.)

Prostaglandin (PG) E2 is involved in a number of physiological and path op hysiologicaI events in many tissues. PGE2 mediates its actions through interaction with specific plasma-membrane G-protein coupled receptors (GPCR's). There are four subtypes of PGE2 receptors: EP1, EP2, EP3 and EP4, classified by their different pharmacological profiles and signal transduction pathways. EP4 agonists have potential therapeutic benefit in diseases such as osteoporosis (EP4 mediates the bone anabolic actions of PGE 2), but possibly in other areas such as asthma. A characteristic feature of GPCR's is their ability to undergo agonist-induced desensitization and this response may limit the therapeutic utility of agonists due to tachyphylaxis.<br>This thesis outlines [1] the agonist-induced regulation of EP4 by PGE2; [2] the development of a novel selective agonist of EP 4 that also mediates EP4 desensitization; and [3] the discovery of a new role for EP4 in mouse models of allergic lung inflammation by employing this selective agonist. PGE2 challenge of EP 4 in human embryonic kidney cells results in desensitization of intracellular signalling responses (cAMP), phosphorylation independent of protein kinase A and sequestration. These events are mediated by sequences in the carboxyl-terminal tail of EP4. EP4 agonists were discovered by preparing analogues of PGE2 by replacing the hydroxycyclopentanone ring by a lactam. Optimized compound (19a) shows high potency at EP4 and is highly selective over the other seven prostaglandin receptors. In vivo stability was increased further by the addition of a gem di-fluro group on carbon 15 of the molecule. The resulting compound, EP 4_Ags, was employed to selectively elucidate the role of EP4 in mouse models of allergic lung inflammation. The EP4 agonist prevents ovalbumin (OVA)-induced inflammation, airways hyperreactivity (AHR) and T helper (Th) 2 cytokine increases. While interleukin (IL)-13-induced inflammation is not inhibited by the EP4 agonist, AHR is attenuated. These results demonstrate that an EP4 agonist has potent anti-inflammatory activity in a mouse model of allergen-induced lung inflammation. Additionally, EP4 may have effects on AHR independent of its anti-inflammatory activity. Interestingly, the rapid desensitization observed in-vitro did not appear to limit efficacy in-vivo. The role of EP4 in mouse models of allergic lung inflammation is a novel finding and the use of an EP4 agonist may have therapeutic benefit in the treatment of asthma.

The primary function of the uterus during pregnancy is to harbour the growing fetus in a quiescent environment. Upon maturation of the fetus, the uterus generates forceful contractions during labour. Prostaglandins are central in the parturition process. PGE2 in particular, is produced in large quantities by fetal membranes and possible roles include cervical ripening and the stimulation of uterine contractions. PGE2 exhibits a wide spectrum of physiological actions depending on the distribution and subtypes of EP receptors. EP1 and EP3 mediate contractions, but there is no consensus about their relative importance. Preliminary experiments were undertaken to examine the possible expression patterns of EP1 and EP3. The expression data showed there to be no significant changes between the localisation in upper or lower segment biopsies using both RNA and protein samples. However, there was a labour associated change seen in EP3 isoform expression at mRNA level together with changes in the protein expression of EP3 in the lower segment using immunofluorescence. Given that the expression studies suggest that it is the EP3 receptor, and not the EP1 receptor, that is most important in myometrial contractility, I established an in vitro tissue bath to conduct functional studies examining contractility in upper and lower segment myometrial biopsies. My data demonstrated that stretch of term human myometrium results in spontaneous contractions. There was no difference between upper and lower segment myometrium, so subsequent experiments were conducted on lower segment biopsies. The addition of acetyl salicylic acid (a non-selective COX inhibitor) did not completely stop spontaneous contractility but reduced the total work done significantly. This could be reversed by add back of PGE2. Prostaglandins are therefore significant but not crucial for spontaneous contractility. Both PGE2 and PGF2α increased the total work done significantly compared to spontaneous contractions; E2 more so than F2α. The PGF2α antagonist did not inhibit spontaneous contractions, but did inhibit PGF2α induced contractions. The EP1 antagonist did not inhibit spontaneous contractions but EP3 antagonist did. These results suggest that an EP3 antagonist is a better candidate as a new tocolytic compound compared to FP or EP1 antagonist.

Ischaemic stroke instigates a series of pathological mechanisms which contribute to injury. Despite significant research in this field successful clinical treatment is limited. This highlights the need to identify novel therapeutic targets in order to assess whether clinical investigation is warranted. The enzyme cyclooxygenase-2 (COX-2) is a key contributor to inflammatory injury following stroke. Upregulation of this enzyme results in increased prostanoid synthesis, which mediate many physiological and pathological functions. Prostaglandin E₂ (PGE₂) is a key mediator in inflammation and activation of its receptor subtypes is both neuroprotective and neurotoxic. COX-2 inhibition in animal models of stroke has demonstrated neuroprotection. However, long term arthritis trials have revealed detrimental effects of COX-2 inhibitors. This highlights the need to identify mediators of the detrimental effects of COX-2 and capitalise those that mediate the beneficial effects. The aim of this study was to investigate the role of the PGE₂ receptor EP₄ following in vitro and in vivo ischaemia. Organotypic hippocampal sliced cultures (OHSCs) were exposed to oxygen and glucose deprivation (OGD). Treatment with a selective EP₄ agonist following OGD significantly reduced cell death, whereas application of the EP₄ receptor antagonist exacerbated injury. C57/BL6 mice were subjected to focal cerebral ischaemia via middle cerebral artery occlusion (MCAO). Administration of the selective EP₄ agonist significantly reduced infarct volume and prevented the decline in neurological function. COX-2 inhibition and EP₄ receptor stimulation resulted in similar levels of protection both in vitro and in vivo ischaemia. EP₄ receptor expression was assessed using immunohistochemistry and real time-PCR. This study provides evidence that selective activation of the EP₄ receptor following ischaemic injury is as neuroprotective as COX-2 inhibition but possibly without the deleterious side effects of COX-2 inhibitors. This supports the concept of targeting protective prostaglandin receptor signalling as a potential therapeutic target for stroke.

Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina<br>Aspirin-intolerant asthma (AIA) is a syndrome where the interplay between cyclooxygenase (COX) and lipoxygenase (LOX) pathways is evident and is characterized by several abnormalities in the regulation and biosynthesis of eicosanoid mediators and eicosanoid receptors. Several observations indicate the presence of a complex change in the arachidonic acid (AA) metabolism in patients who suffer from AIA. However, previous studies showed some discrepant results when upper and lower airways were analyzed, and there are no clear explanations for this. The inflammatory responses in upper airways are often associated with the presence of nasal polyps, structures never seen in the lower airways. In this study, upper and lower airways were compared, in order to verify if the multiple factors of the COX pathway are differentially regulated considering both respiratory tracts. To perform the experiments, fibroblasts from nasal mucosa (NM) and bronchial mucosa (BM) of non-asthmatic subjects undergoing corrective surgery and fibrobronchoscopy, respectively, (control group) were compared with NM, nasal polyp (NP), and BM fibroblasts isolated from non-asthmatic and AIA patients suffering from chronic rhinosinusitis (CRS) with NP. The data presented in this investigation suggest that in lower airways, the presence of aspirin intolerance does not seem to alter the expression of COX enzymes or the production of prostaglandin (PG) E2. Considering the expression of the EP receptors, the data suggest significant differences through fibroblasts from upper airways tissues. The differences observed between upper and lower airways combined with others verified in previous studies might contribute to the pathogenesis of nasal polyposis.

Rat hepatocytes have previously been reported to possess prostaglandin E₂ receptors of the EP₃-type (EP₃-receptors) that inhibit glucagonstimulated glycogenolysis by decreasing cAMP. Here, the isolation of a functional EP₃ϐ receptor cDNA clone from a rat hepatocyte cDNA library is reported. This clone can be translated into a 362-amino-acid protein, that displays over 95% homology to the EP₃ϐ receptor from mouse mastocytoma. The amino- and carboxy-terminal region of the protein are least conserved. Transiently transfected HEK 293 cells expressed a single binding site for PGE₂ with an apparent Kd of 15 nM. PGE₂ > PGF₂α > PGD₂ competed for [³H]PGE₂ binding sites as did the EP₃ receptor agonists M&B 28767 = sulprostone > misoprostol but not the EP₁ receptor antagonist SC 19220. In stably transfected CHO cells M&B 28767 > sulprostone = PGE₂ > misoprostol > PGF₂α inhibited the forskolin-elicited cAMP formation. Thus, the characteristics of the EP₃ϐ receptor of rat hepatocytes closely resemble those of the EP₃ϐ receptor of mouse mastocytoma.

The prostaglandins comprise a group of bioactive lipids generated from arachidonic acid by cyclooxygenases and cell type-specific prostaglandin and thromboxane synthases. Prostaglandins mediate local cell signaling interactions by activation of G-protein coupled prostanoid receptors. Because the prostaglandins and their receptors are active in all tissues, they have an extraordinarily broad spectrum of physiological and pathophysiological functions that have hampered the development of safe prostanoid-based medications. This situation has emphasized the importance of understanding the functional properties of the prostanoid receptors and developing selective ligands capable of being used in patient care.The aims of this project were to identify novel regulatory functions of endogenous EP and FP prostanoid receptors in cultured human cells. Our results show that activation of EP₂ receptors in human microglia and astrocytes led to increased secretion of BDNF, a growth factor that regulates the survival of neurons. In the same cell lines, FP receptors regulate the induction of TNF-&alpha; gene expression through a classic G_q-PKC pathway. In microglia these FP receptors also stimulate a novel signaling crosstalk mechanism involving the up-regulation of TCF transcriptional function by Raf kinases, which culminates in the expression of the angiogenic inducer Cyr61. FP receptors also regulate the induction of angiogenic immediate early genes in cultured ciliary muscle cells, which may constitute the early steps in a mechanism by which commercial FP agonists reduce intraocular pressure in glaucoma therapy.The up-regulation of BDNF through glial EP₂ receptors constitutes a mechanism by which elevated PGE₂ in the inflamed brain might elicit either healing processes in the brain or neuronal apoptosis. On the other hand, induction of TNF-&alpha; and Cyr61 by glial FP receptors may mediate neuroinflammation and may also contribute to glioma tumor growth. Stimulation of FP receptors in the ciliary muscle leads to the induction of immediate early genes capable of coordinating tissue remodeling processes that have been previously documented. The results of these studies suggest novel regulatory functions of the prostanoid receptors in the brain and eye. Furthermore, these findings provide insight on how the selective modulation of the EP₂ and FP receptors might be therapeutically advantageous.

Die Ausbildung und der Schweregrad einer Anaphylaxie kann durch verschiedene Co-Faktoren beeinflusst werden. Zu diesen zählen die nichtsteroidalen Antiphlogistika (NSAIDs), die ihre Wirkung über die Inhibition der COX entfalten. Wie NSAIDs den Schweregrad der Anaphylaxie beeinflussen, ist bisher nicht genau bekannt. Interessanterweise zeigen Anaphylaxie-Patienten mit einer NSAID-Hypersensibilität niedrige Konzentrationen des regulatorischen Prostaglandins E2 (PGE2). Zudem zeigen ASA-tolerante und –intolerante Asthma-Patienten variable anaphylaktische Sensitivitäten. Anhand der vorliegenden Arbeit sollte untersucht werden, ob sich eine PGE2-Dysregulation auf die Ausbildung und den Schweregrad der Anaphylaxie auswirkt und ob diese durch genetische Prädispositionen gefördert werden kann. Dazu wurden zunächst die PGE2 Konzentration im Serum von ANA-Patienten und gesunden Individuen gemessen. ANA-Patienten zeigten reduzierte PGE2 Level, die invers mit dem Schweregrad der ANA korrelierten. Unterstützend weisen zwei in der Allergieforschung häufig verwendete Mauslinien, Balb/c und C57BL/6, unterschiedliche PGE2 Level auf, die wiederum invers mit dem ANA-Schweregrad korrelierten. Eine Stabilisierung der PGE2 Konzentration mittels eines pharmakologischen Inhibitors der Hydroxyprostaglandin-Dehydrogenase (15-PGDH-I) in vivo führte zu einer Verbesserung des ANA Schweregrades. Um in diesem Zusammenhang den Einfluss von ASA und PGE2 besser zu verstehen, wurde das Model der systemisch passiven ANA im Mausmodel eingesetzt. ASA verschlimmerte den Schweregrad der ANA durch die Inhibition der COX1/2. PGE2 konnte diese Verschlimmerung über die EP Rezeptoren 2, 3 und 4 reduzieren. Um die zugrundeliegenden Mechanismen der Wirkweise von exogenem PGE2 und EP-Agonisten besser zu verstehen, wurden diese Zusammenhänge in murinen und humanen Mastzellen untersucht. PGE2 reduzierte die Schwere der ANA durch Inhibition der Mastzell-Aktivität in diesem System über die Rezeptoren EP2 und EP4. Anhand der vorliegenden Arbeit konnte gezeigt werden, dass bereits homöostatische PGE2 Konzentrationen die Aktivität der Mastzelle verändern und vor einer schweren ANA schützen. Zudem kann der Grad der ANA und der Einfluss des PGE2 auf die Mastzellantwort durch genetische Prädisposition beeinflusst werden. Die pharmakologische Stabilisierung des PGE2 könnte daher eine vielversprechende, therapeutische wie auch vorbeugende Strategie zur Behandlung risikoreicher ANA- Patienten sein.<br>The clinical outcome of anaphylaxis (ANA) can be affected by several co-factors. Non-steroidal anti-inflammatory drugs (NSAIDs) are well-known co-factors of ANA acting via COX-inhibition. The NSAIDs-mediated mechanisms altering the severity of ANA are not well-defined. It is reported that patients of ASA (NSAID)-hypersensitivity show low levels of the regulatory prostaglandin E2 (PGE2). Moreover, the effectiveness of PGE2 administration in such patients suggests a critical role of PGE2 in ASA hypersensitivity. In addition, patients of ASA-tolerant and ASA-intolerant asthma show variable ANA sensitivities suggesting a role of genetic variation in susceptibility. The aim of this thesis was to study whether and how PGE2 dysregulation predisposes to ANA and whether genetic pre-dispositions affect the PGE2 system and therefore ANA susceptibility. First, sera from ANA patients and healthy individuals were analyzed for PGE2 levels. ANA patients were characterized by reduced PGE2 levels which inversely correlated with the severity of ANA. This disparity was confirmed by differential PGE2 levels between Balb/c and BL/6 strains, two genetic mouse strains frequently employed in allergy research. PGE2 levels in these mice were again inversely related with the severity of ANA. Results were confirmed by in vivo PGE2 stabilization using 15-hydroxyprostaglandin dehydrogenase inhibitor (15-PGDH-I). Pharmacological PGE2 stabilization ameliorated ANA severity in mice. A passive systemic ANA (PSA) model was applied to study the impact of ASA on ANA severity and the role of PGE2 in this context. ASA aggravated ANA by inhibiting COX-1/COX-2, while PGE2 reduced the aggravation through EP receptors 2, 3 and 4. To delineate the underlying mechanisms, murine and human mast cells were used to study the impact of exogenous PGE2 and EP agonists. PGE2 attenuated ANA severity by inhibiting MC activation through EP2 and EP4 receptors and interfering with MC signaling. In summary, this thesis demonstrates that homeostatic levels of PGE2 modulate MC activation and protect against ANA severity. The impact of PGE2 on MC responses and ANA susceptibility is governed by genetic variation. Pharmacological stabilization of PGE2 may prove to be a therapeutic or preventive strategy in the management of high-risk ANA patients.

本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである<br>Kyoto University (京都大学)<br>0048<br>新制・課程博士<br>博士(医学)<br>甲第6737号<br>医博第1837号<br>新制||医||656(附属図書館)<br>UT51-97-H121<br>京都大学大学院医学研究科内科系専攻<br>(主査)教授 大熊 稔, 教授 伊藤 和彦, 教授 中尾 一和<br>学位規則第4条第1項該当

We are unceasingly exposed to potentially harmful microorganisms. The battle against threatening infectious agents includes activation of both the innate and of the adaptive immune systems. Illness responses are elicited and include inflammation, fever, decreased appetite, lethargy and increased sensitivity to painful stimuli in order to defeat invaders. While many of these signs of disease are controlled by the central nervous system, it has remained an enigma how signals from the peripheral immune system reach the brain through its blood-brain barrier, which precludes macromolecules, including cytokines, from diffusing into the brain parenchyma. Previous findings indicate the existence of a pathway across the blood-brain barrier, which includes binding of the cytokine interleukin-1 (IL-1) to its receptor in the brain vessels, thereby inducing the production of the prostaglandin E2 (PGE2) synthesizing enzymes cyclooxygenase-2 (Cox-2) and microsomal prostaglandin E synthase-1 (mPGES-1), which ultimately synthesize PGE2. PGE2 subsequently binds to any of the four prostaglandin E2 (EP) -receptors. Previous results from our laboratory have suggested that this pathway plays a critical role in the febrile response to infectious stimuli. The present thesis aims at further investigating the molecular events underlying immune-to-brain signalling, with special emphasis on fever, hypothalamic-pituitary-adrenal (HPA) -axis activation and anorexia and their connection to signalling molecules of the cytokine and prostaglandin families, respectively. In paper I, the molecular processes linking the proinflammatory cytokine interleukin-6 (IL-6) and PGE2 in the febrile response were investigated. Both IL-6 and PGE2 have been shown to be critical players in the febrile response, although the molecular connections are not known, i.e. if IL-6 exerts its effects up- or downstream of PGE2. Mice deficient in IL-6 were unable to respond to bacterial lipopolysaccharide (LPS) with a febrile response, but displayed similar induction of Cox-2 and mPGES-1, and similar concentrations of PGE2 in the cerebrospinal fluid as wild-type mice. Paradoxically, the IL-6 deficient mice responded with a dose-dependent elevation of body temperature in response to intracerebroventricularly injected PGE2. Furthermore, IL-6 per se was not pyrogenic when injected peripherally in mice, and did not cause increased levels of PGE2 in cerebrospinal fluid. IL-6 deficient mice were not refractory to the action of PGE2 because of excess production of some hypothermia-producing factor, since administration of a Cox-2 inhibitor in LPS-challenged IL-6 deficient mice did not unmask any hypothermic response, and neutralization of tumor necrosis factor α (TNFα), associated with hypothermia, did not produce fever in LPS-challenged IL-6 deficient mice. These data indicate that IL-6 rather than exerting its effects up- or down-stream of PGE2 affects some process in parallel to PGE2, perhaps by influencing the diffusion and binding of PGE2 onto its target neurons. In papers II and III, we injected the proinflammatory cytokine IL-1β in free-fed wild-type mice, in mice with a deletion of the gene encoding mPGES-1, or in mice deficient in the EP1, EP2 and EP3. Food intake was continuously measured during their active period, revealing that mPGES-1 deficient mice were almost completely resistant to anorexia induced by IL-1β. However, all of the investigated EP receptor deficient mice exhibited a normal profound anorexic response to IL-1β challenge, suggesting that the EP4 is the critical receptor that mediates IL-1β-induced anorexia. We also investigated the role of mPGES-1 in anorexia induced by lipopolysaccharide (LPS) in mPGES-1 deficient mice. The profound anorexic response after LPS-challenge was similar in mPGES-1 deficient and wild-type mice. To further investigate the anorectic behaviour after LPS injection, we pre-starved the animals for 22 hours before injecting them with LPS. In this paradigm, the anorexia was less profound in mPGES-1 knock-out mice. Our results suggest that while the inflammatory anorexia elicited by peripheral IL-1β seems largely to be dependent on mPGES-1-mediated PGE2 synthesis, similar to the febrile response, the LPS-induced anorexia is independent of this mechanism in free-fed mice but not in pre-starved animals. In papers IV and V, the role of prostanoids for the immune-induced HPA-axis response was investigated in mice after genetic deletion or pharmacological inhibition of prostanoid-synthesizing enzymes, including Cox-1, Cox-2, and mPGES-1. The immediate LPS-induced release of ACTH (adrenocorticotropic hormone and corticosteroids was critically dependent on Cox-1 derived prostanoids and occurred independently of Cox-2 and mPGES-1 derived PGE2. In contrast, the delayed HPA-axis response was critically dependent on immune-induced PGE2, synthesized by Cox-2 and mPGES-1, and occurred independently of Cox-1 derived enzymes. In addition, in the mPGES-1 deficient mice, the synthesis of CRH hnRNA and mRNA was decreased in the paraventricular nucleus of the hypothalamus after LPS-challenge, indicating that the delayed hormone secretion was mediated by PGE2-induced gene-transcription of CRH in the hypothalamus. The expression of the c-fos gene and Fos protein, an index of synaptic activation, was maintained in the paraventricular nucleus and its brainstem afferents both after unselective and Cox-2 selective inhibition as well as in Cox-1, Cox-2, and mPGES-1 knock-out mice. This suggests that the immune-induced neuronal activation of autonomic relay nuclei occurs independently of prostanoid synthesis and that it is insufficient for eliciting stress hormone release.

Le Gengyun.<br>Thesis submitted in: December 2002.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.<br>Includes bibliographical references (leaves 161-182).<br>Abstracts in English and Chinese.<br>Abstract --- p.i<br>Abbreviations --- p.v<br>Acknowledgements --- p.vii<br>Publications --- p.viii<br>Table of Contents --- p.ix<br>Chapter Chapter 1 --- INTRODUCTION --- p.1<br>Chapter 1. --- Vasoconstrictors --- p.1<br>Chapter 1.1 --- An overview of vascular smooth muscle contraction --- p.1<br>Chapter 1.2 --- Strong and weak vasoconstrictors --- p.5<br>Chapter 1.2.1 --- Mechanisms involved in TP receptor vasoconstriction --- p.6<br>Chapter 1.2.1.1 --- Brief introduction to the TP receptor --- p.6<br>Chapter 1.2.1.2 --- Second messenger systems --- p.6<br>Chapter 1.2.1.3 --- G-protein-linked pathways --- p.7<br>Chapter 1.2.1.3.1 --- G proteins --- p.7<br>Chapter 1.2.1.3.2 --- G-protein-linked TP receptor signal transduction --- p.8<br>Chapter 1.2.2 --- Mechanisms involved in α1-adrenoceptor vasoconstriction --- p.8<br>Chapter 1.2.2.1 --- Brief introduction to the α1-adrenoceptor --- p.8<br>Chapter 1.2.2.2 --- Second messenger systems --- p.9<br>Chapter 1.2.2.3 --- G-protein-linked α-adrenoceptor signal transduction --- p.9<br>Chapter 1.3 --- Prostanoid EP3 receptor agonists (weak vasoconstrictors) --- p.10<br>Chapter 1.3.1 --- Prostanoids --- p.10<br>Chapter 1.3.1.1 --- Biochemical characteristics of prostanoids --- p.10<br>Chapter 1.3.1.1.1 --- Biosynthesis of prostanoids --- p.10<br>Chapter 1.3.1.1.2 --- Metabolism of prostanoids --- p.11<br>Chapter 1.3.1.2 --- Prostanoid receptors --- p.13<br>Chapter 1.3.1.2.1 --- Structures --- p.13<br>Chapter 1.3.1.2.2 --- Current Status of Classification --- p.14<br>Chapter 1.3.1.2.3 --- Signal transduction --- p.16<br>Chapter 1.3.1.2.4 --- Distribution --- p.18<br>Chapter 1.3.1.2.5 --- Physiological functions --- p.18<br>Chapter 2. --- Interactions between vasoconstrictors --- p.19<br>Chapter 2.1 --- Cross-talk between G-protein-coupled receptors --- p.19<br>Chapter 2.1.1 --- Cross-talk between different receptor families --- p.19<br>Chapter 2.1.2 --- Cross-talk between subtypes of the same receptor family --- p.21<br>Chapter 2.1.3 --- Cross-talk at the effector level --- p.23<br>Chapter 2.2 --- Proposed pathways involved in synergistic interactions --- p.24<br>Chapter 2.2.1 --- Rho and Rho-associated kinase --- p.24<br>Chapter 2.2.1.1 --- Rho family and its identification --- p.24<br>Chapter 2.2.1.2 --- Mechanism(s) of Rho contribution in vasoconstriction --- p.25<br>Chapter 2.2.1.3 --- Interactions between Rho and other pathways --- p.26<br>Chapter 2.2.2 --- Receptor tyrosine kinases --- p.29<br>Chapter 2.2.2.1 --- RTK family --- p.29<br>Chapter 2.2.2.2 --- Activation of RTKs --- p.29<br>Chapter 2.2.2.3 --- Mechanism(s) of RTK contribution in vasoconstriction --- p.30<br>Chapter 2.2.2.4 --- Interactions between RTKs and MAPKs --- p.31<br>Chapter 2.2.3 --- Mitogen-activated protein kinase --- p.34<br>Chapter 2.2.3.1 --- p38 MAPK --- p.35<br>Chapter 2.2.3.2 --- JNK MAPK --- p.35<br>Chapter 2.2.3.3 --- ERK MAPK --- p.36<br>Chapter 2.2.3.4 --- Interactions between MAPK and GPCRs --- p.37<br>Chapter Chapter 2 --- FORCE MEASUREMENT SYSTEM --- p.41<br>Chapter 1. --- Introduction --- p.41<br>Chapter 2. --- Materials --- p.41<br>Chapter 2.1 --- Drugs --- p.41<br>Chapter 2.2 --- Chemicals --- p.41<br>Chapter 2.3 --- Solutions --- p.46<br>Chapter 3. --- Methods --- p.46<br>Chapter 3.1 --- Isolated smooth muscle preparations and organ bath set-up --- p.46<br>Chapter 3.2 --- Data analysis --- p.47<br>Chapter Chapter 3 --- VASOCONSTRICTORS AND THEIR INTERACTIONS --- p.48<br>Chapter 1. --- Introduction --- p.48<br>Chapter 2. --- Materials and Methods --- p.48<br>Chapter 2.1 --- Materials --- p.48<br>Chapter 2.2 --- Methods --- p.51<br>Chapter 2.2.1 --- Isolated tissue preparations --- p.51<br>Chapter 2.2.2 --- Experimental protocols --- p.51<br>Chapter 2.2.3 --- Statistical analysis --- p.52<br>Chapter 3. --- Results --- p.55<br>Chapter 3.1 --- Typical vasoconstrictor profiles of agonists --- p.55<br>Chapter 3.1.1 --- Sulprostone contraction --- p.55<br>Chapter 3.1.2 --- U-46619 contraction --- p.55<br>Chapter 3.1.3 --- Phenylephrine contraction --- p.56<br>Chapter 3.2 --- Synergistic interactions between sulprostone and strong vasoconstrictors --- p.58<br>Chapter 3.2.1 --- Enhancement of U-46619 response by sulprostone --- p.58<br>Chapter 3.2.2 --- Enhancement of phenylephrine response by sulprostone --- p.58<br>Chapter 3.2.3 --- Enhancement of sulprostone response by phenylephrine --- p.58<br>Chapter Chapter 4 --- INVESTIGATION OF PATHWAYS INVOLVED IN EP3 AGONIST- INDUCED VASOCONSTRICTION --- p.64<br>Chapter 1. --- Introduction --- p.64<br>Chapter 2. --- Materials and methods --- p.65<br>Chapter 2.1 --- Materials --- p.65<br>Chapter 2.2 --- Methods --- p.65<br>Chapter 2.2.1 --- Isolated tissue preparations --- p.65<br>Chapter 2.2.2 --- Experimental protocols --- p.65<br>Chapter 2.2.3 --- Statistical analysis --- p.69<br>Chapter 3. --- Results --- p.70<br>Chapter 3.1 --- Effects of tyrosine kinase inhibitors --- p.70<br>Chapter 3.2 --- Effects of MAPK inhibitors --- p.82<br>Chapter 3.2.1 --- Effects of MAPK inhibitors on U-46619 responses --- p.82<br>Chapter 3.2.2 --- Effects of MAPK inhibitors on sulprostone responses --- p.91<br>Chapter 3.2.3 --- Effects of MAPK inhibitors on phenylephrine responses --- p.100<br>Chapter 3.3 --- Effects of Rho-kinase inhibitors --- p.104<br>Chapter Chapter 5 --- TRANSFECTED CELL LINE SYSTEM --- p.111<br>Chapter 1. --- Introduction --- p.111<br>Chapter 2. --- Materials and methods --- p.114<br>Chapter 2.1 --- Materials --- p.114<br>Chapter 2.1.1 --- Plasmids and vectors --- p.114<br>Chapter 2.1.2 --- Radioactive agents --- p.114<br>Chapter 2.1.3 --- Chemicals --- p.114<br>Chapter 2.1.4 --- Restriction digest enzymes --- p.115<br>Chapter 2.1.5 --- "Culture media, buffers and solutions" --- p.115<br>Chapter 2.1.5.1 --- Culture media<br>Chapter 2.1.5.2 --- Buffers and solutions --- p.115<br>Chapter 2.2 --- Methods --- p.116<br>Chapter 2.2.1 --- Transfected cell lines --- p.116<br>Chapter 2.2.1.1 --- Subcloning of hEP3-1 receptor and hTP receptor cDNA --- p.116<br>Chapter 2.2.1.1.1 --- Plasmid recovery<br>Chapter 2.2.1.1.2 --- Preparation of competent cells --- p.116<br>Chapter 2.2.1.1.3 --- Transformation of competent cells --- p.117<br>Chapter 2.2.1.1.4 --- Extraction of DNA by QIAGEN Plasmid Mini Kit --- p.117<br>Chapter 2.2.1.1.5 --- Restriction enzymes digestion and dephosphorylation --- p.117<br>Chapter 2.2.1.1.6 --- DNA recovery and ligation<br>Chapter 2.2.1.1.7 --- Positive recombinant DNA selection --- p.119<br>Chapter 2.2.1.2 --- Cell culture --- p.119<br>Chapter 2.2.1.3 --- Transient transfection of CHO cells --- p.121<br>Chapter 2.2.1.4 --- Mesurement of adenylate cyclase activity --- p.121<br>Chapter 2.2.1.4.1 --- Preparation of columns --- p.121<br>Chapter 2.2.1.4.2 --- [3H]-cAMP assays --- p.122<br>Chapter 2.2.1.5 --- Measurement of phospholipase C activity --- p.122<br>Chapter 2.2.1.5.1 --- Preparation of columns --- p.123<br>Chapter 2.2.1.5.2 --- [3H]-inositol phosphate assay --- p.123<br>Chapter 2.2.2 --- Data analysis --- p.124<br>Chapter 3. --- Results --- p.125<br>Chapter 3.1 --- Subcloning of hEP3-1and hTPα receptor cDNA into expression vectors --- p.125<br>Chapter 3.2 --- Measurement of cAMP and IP production in transfected CHO cells --- p.133<br>Chapter 3.2.1 --- Effect of varying receptor cDNA concentration on agonist-stimulated [3H]-cAMP and [3H]-IP production in transiently transfected CHO cells --- p.133<br>Chapter 3.2.2 --- Effect of agonists on intracellular [3H]-IP or [3H]-cAMP productionin CHO cells transfected with hTPα or hEP3-1 --- p.133<br>Chapter 3.3 --- Summary --- p.134<br>Chapter Chapter 6 --- GENERAL DISCUSSION AND CONCLUSIONS --- p.137<br>Chapter 1. --- Vasoconstrictors and their interactions --- p.137<br>Chapter 1.1 --- Vasoconstrictors --- p.137<br>Chapter 1.2 --- Synergism --- p.138<br>Chapter 2. --- Investigation of possible pathways --- p.140<br>Chapter 2.1 --- Rho-associated kinase --- p.140<br>Chapter 2.2 --- Receptor tyrosine kinase --- p.147<br>Chapter 2.3 --- Mitogen-activated protein kinase (MAPK) --- p.151<br>Chapter 3. --- Effect of vehicles --- p.155<br>Chapter 4. --- Biochemical studies in transfected CHO cells --- p.157<br>Chapter 5. --- Conclusions --- p.158<br>Appendix I --- p.159<br>Buffers and Solutions used in transfected system --- p.159<br>Chapter 1. --- Buffers --- p.159<br>Chapter 2. --- Solutions --- p.159<br>REFERENCES --- p.161

碩士<br>國立臺灣大學<br>臨床牙醫學研究所<br>101<br>Aim: Bacterial infection and mechanical injuries can cause pulp inflammation. Prostanoids production of pulp cells were involved in the inflammatory and healing processes of dental pulp. These contradictory actions of PGE2 further support the presence of diverse PGE2 receptor isoforms in different tissues or cells. However, the significance of EP receptors in human dental pulp has not yet been fully described. The aim of the study is to investigate the role of EP receptors and their signaling in regulation of the dental pulp. Materials and Methods: Primary-cultured human dental pulp cells were treated with PGE2 or EP receptor agonist. In some experiments, cells were pretreated with H89 (a PKA inhibitor), or SQ22536 (an ACs inhibitor) 30 minutes before adding PGE2. Cell migration assay has been used to examine signaling events. Collagen content was determined by Sircol Collagen assay. Cell differentiation and mineralization was evaluated by alkaline phosphatase (ALP) staining. Changes in mRNA expression were determined by reverse-transcriptase polymerase chain reaction (RT-PCR). Result:Cell under the treatment of PGE2 (0.1μM~10μM) showed a decrease of collagen formation and cell migration and also showed a decrease of ALP activity. CAY10598 (EP2 agonist) at low dose (0.5μM , 1μM) increased ALP activity. 19R-OH PGE2 (EP2 agonist) showed a decrease in cell migration assay and collagen formation assay . Pretreatment by H89 (a PKA inhibitor), or SQ22536 (an ACs inhibitor) were effective to reverse the inhibitory effect of PGE2 in ALP stain and in the cell migration assay. PGE2 can induce the expression of AP-1 transcription factors. Conclusion: Signal transduction of PGE2 in human dental pulp cell is complex, AC/PKA may take part in this complex system via EP2. PGE2 may be involved in dental pulp inflammation and repair processes via induction of AP-1 transcription factors.

Hung Hoi Yan.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.<br>Includes bibliographical references (leaves 138-160).<br>Abstracts in English and Chinese.<br>ABSTRACT --- p.i<br>ACKNOWLEDGEMENTS --- p.v<br>PUBLICATIONS BASED ON THE WORK IN THIS THESIS --- p.vi<br>TABLE OF CONTENTS --- p.vii<br>ABBREVIATIONS --- p.ix<br>Chapter CHAPTER 1 --- INTRODUCTION --- p.1<br>Chapter 1.1 --- Prostanoids and vasoconstriction --- p.1<br>Chapter 1.1.1 --- EP3 receptors --- p.2<br>Chapter 1.1.2 --- EP1 receptors --- p.16<br>Chapter 1.1.3 --- FP receptors --- p.23<br>Chapter 1.1.4 --- TP receptors --- p.30<br>Chapter 1.2 --- Role of Ca2+ in vascular smooth muscle contraction --- p.36<br>Chapter 1.2.1 --- Ca2+ as second messenger --- p.36<br>Chapter 1.2.2 --- Ca2+ sensitization --- p.41<br>Chapter 1.3 --- Aim of study --- p.48<br>Chapter CHAPTER 2 --- METHODS AND MATERIALS --- p.49<br>Chapter 2.1 --- Experiments with rat femoral artery --- p.49<br>Chapter 2.2 --- Experiments with guinea-pig trachea --- p.56<br>Chapter 2.3 --- Materials --- p.59<br>Chapter 2.4 --- Data analysis --- p.61<br>Chapter 2.5 --- Measurement of rat knee joint blood flow --- p.62<br>Chapter CHAPTER 3 --- RESULTS --- p.68<br>Chapter 3.1 --- Effects of EP3 agonists and other vasoactive agents on the rat femoral artery preparation --- p.68<br>Chapter 3.2 --- Interactions between EP3 agonists and other vasoactive agents --- p.69<br>Chapter 3.2.1 --- Interactions with phenylephrine --- p.69<br>Chapter 3.2.2 --- Interactions with KCl --- p.71<br>Chapter 3.3 --- Effect of nifedipine --- p.72<br>Chapter 3.4 --- Effects of Rho-kinase inhibitors --- p.73<br>Chapter 3.5 --- Effect of EP1 receptor antagonist --- p.76<br>Chapter 3.6 --- Other properties of the rat femoral artery --- p.77<br>Chapter 3.8 --- Effect of sulprostone on blood flow of rat knee joint --- p.79<br>Chapter CHAPTER 4 --- DISCUSSION --- p.118<br>Chapter 4.1 --- Effect of PGE analogues on rat femoral artery --- p.118<br>Chapter 4.1.1 --- Prostanoid receptor (s) responsible for the contractile effects --- p.118<br>Chapter 4.1.2 --- Prostanoid Receptors involved in the synergism --- p.122<br>Chapter 4.1.3 --- Synergism models --- p.124<br>Chapter 4.2 --- Mechanisms of synergistic contractions --- p.126<br>Chapter 4.2.1 --- Role of Ca2+ influx --- p.126<br>Chapter 4.2.2 --- Role of Ca2+ sensitization --- p.127<br>Chapter 4.3 --- Effect of sulprostone in vivo --- p.132<br>Chapter 4.4 --- Conclusion --- p.136<br>REFERENCES --- p.138

Indiana University-Purdue University Indianapolis (IUPUI)<br>Adult hematopoietic stem cells (HSC) are routinely used to reconstitute hematopoiesis after myeloablation; however, transplantation efficacy and multilineage reconstitution can be limited by inadequate HSC number, or poor homing, engraftment or self-renewal. We have demonstrated that mouse and human HSC express prostaglandin E2 (PGE2) receptors, and that short-term ex vivo exposure of HSC to PGE2 enhances their homing, survival and proliferation, resulting in increased long-term repopulating cell and competitive repopulating unit (CRU) frequency. HSC pulsed with PGE2 are more competitive, as determined by head-to-head comparison in a competitive transplantation model. Enhanced HSC frequency and competitive advantage is stable and maintained upon multiple serial transplantations, with full multi-lineage reconstitution. PGE2 increases HSC CXCR4 mRNA and surface expression and enhances their migration to SDF-1α in vitro and homing to bone marrow in vivo and stimulates HSC entry into and progression through cell cycle. In addition, PGE2 enhances HSC survival, associated with an increase in Survivin mRNA and protein expression and reduction in intracellular active caspase-3. While PGE2 pulse of HSC promotes HSC self-renewal, blockade of PGE2 biosynthesis with non-steroidal anti-inflammatory drugs (NSAIDs) results in expansion of bone marrow hematopoietic progenitor cells (HPC). We co-administered NSAIDs along with the mobilizing agent granulocyte-colony stimulating factor (G-CSF) and evaluations of limiting dilution transplants, assays monitoring neutrophil and platelet recoveries, and secondary transplantations, clearly indicate that NSAIDs facilitate mobilization of a hematopoietic graft with superior functional activity compared to the graft mobilized by G-CSF alone. Enhanced mobilization has also been confirmed in baboons mobilized with G-CSF and a NSAID. Increases in mobilization are the result of a reduction of signaling through the PGE2 receptor EP4, which results in marrow expansion and reduction in the osteoblastic HSC niche. We also identify a new role for cannabinoids, an eicosanoid with opposing functions to PGE2, in hematopoietic mobilization. Additionally, we demonstrate increased survival in lethally irradiated mice treated with PGE2, NSAIDs, or the hypoxia mimetic cobalt chloride. Our results define novel mechanisms of action whereby eicosanoids regulate HSC and HPC function, and characterize novel translational strategies for hematopoietic therapies.