Artigos de revistas: "Human Chitinase"

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Schimpl, Marianne, Christina L. Rush, Marie Betou, Ian M. Eggleston, Anneliese D. Recklies e Daan M. F. van Aalten. "Human YKL-39 is a pseudo-chitinase with retained chitooligosaccharide-binding properties". Biochemical Journal 446, n.º 1 (27 de julho de 2012): 149–57. http://dx.doi.org/10.1042/bj20120377.

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The chitinase-like proteins YKL-39 (chitinase 3-like-2) and YKL-40 (chitinase 3-like-1) are highly expressed in a number of human cells independent of their origin (mesenchymal, epithelial or haemapoietic). Elevated serum levels of YKL-40 have been associated with a negative outcome in a number of diseases ranging from cancer to inflammation and asthma. YKL-39 expression has been associated with osteoarthritis. However, despite the reported association with disease, the physiological or pathological role of these proteins is still very poorly understood. Although YKL-39 is homologous to the two family 18 chitinases in the human genome, it has been reported to lack any chitinase activity. In the present study, we show that human YKL-39 possesses a chitinase-like fold, but lacks key active-site residues required for catalysis. A glycan screen identified oligomers of N-acetylglucosamine as preferred binding partners. YKL-39 binds chitooligosaccharides and a newly synthesized derivative of the bisdionin chitinase-inhibitor class with micromolar affinity, through a number of conserved tryptophan residues. Strikingly, the chitinase activity of YKL-39 was recovered by reverting two non-conservative substitutions in the active site to those found in the active enzymes, suggesting that YKL-39 is a pseudo-chitinase with retention of chitinase-like ligand-binding properties.

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Pinteac, Rucsanda, Xavier Montalban e Manuel Comabella. "Chitinases and chitinase-like proteins as biomarkers in neurologic disorders". Neurology - Neuroimmunology Neuroinflammation 8, n.º 1 (8 de dezembro de 2020): e921. http://dx.doi.org/10.1212/nxi.0000000000000921.

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Chitinases are hydrolytic enzymes widely distributed in nature. Despite their physiologic and pathophysiologic roles are not well understood, chitinases are emerging as biomarkers in a broad range of neurologic disorders, where in many cases, protein levels measured in the CSF have been shown to correlate with disease activity and progression. In this review, we will summarize the structural features of human chitinases and chitinase-like proteins and their potential physiologic and pathologic functions in the CNS. We will also review existing evidence for the role of chitinases and chitinase-like proteins as diagnostic and prognostic biomarkers in inflammatory, neurodegenerative diseases, and psychiatric disorders. Finally, we will comment on future perspectives of chitinase studies in neurologic conditions.

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Madan, Kirtika, Mansi Madan, Swapnil Sharma e Sarvesh Paliwal. "Chitinases: Therapeutic Scaffolds for Allergy and Inflammation". Recent Patents on Inflammation & Allergy Drug Discovery 14, n.º 1 (30 de março de 2020): 46–57. http://dx.doi.org/10.2174/1872213x14666200114184054.

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Background: Chitinases are the evolutionary conserved glycosidic enzymes that are characterized by their ability to cleave the naturally abundant polysaccharide chitin. The potential role of chitinases has been identified in the manifestation of various allergies and inflammatory diseases. In recent years, chitinases inhibitors are emerging as an alluring area of interest for the researchers and scientists and there is a dire need for the development of potential and safe chitinase antagonists for the prophylaxis and treatment of several diseases. Objective: The present review expedites the role of chitinases and their inhibitors in inflammation and related disorders. Methods: At first, an exhaustive survey of literature and various patents available related to chitinases were carried out. Useful information on chitinases and their inhibitor was gathered from the authentic scientific databases namely SCOPUS, EMBASE, PUBMED, GOOGLE SCHOLAR, MEDLINE, EMBASE, EBSCO, WEB OF SCIENCE, etc. This information was further analyzed and compiled up to prepare the framework of the review article. The search strategy was conducted by using queries with key terms “ chitin”, “chitinase”, “chitotrisidase”, “acidic mammalian chitinase”, “chitinase inhibitors”, “asthma” and “chitinases associated inflammatory disorders”, etc. The patents were searched using the key terms “chitinases and uses thereof”, “chitinase inhibitors”, “chitin-chitinase associated pathological disorders” etc. from www.google.com/patents, www.freepatentsonline.com, and www.scopus.com. Results: The present review provides a vision for apprehending human chitinases and their participation in several diseases. The patents available also signify the extended role and effectiveness of chitinase inhibitors in the prevention and treatment of various diseases viz. asthma, acute and chronic inflammatory diseases, autoimmune diseases, dental diseases, neurologic diseases, metabolic diseases, liver diseases, polycystic ovary syndrome, endometriosis, and cancer. In this regard, extensive pre-clinical and clinical investigations are required to develop some novel, potent and selective drug molecules for the treatment of various inflammatory diseases, allergies and cancers in the foreseeable future. Conclusion: In conclusion, chitinases can be used as potential biomarkers in prognosis and diagnosis of several inflammatory diseases and allergies and the design of novel chitinase inhibitors may act as key and rational scaffolds in designing some novel therapeutic agents in the treatment of variety of inflammatory diseases.

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Vega, Karina, Diana Diaz-Arevalo, Karine Bagramyan, Teresa Hong e Markus Kalkum. "A positive feedback mechanism in the regulation of mammalian chitinase responses (56.29)". Journal of Immunology 186, n.º 1_Supplement (1 de abril de 2011): 56.29. http://dx.doi.org/10.4049/jimmunol.186.supp.56.29.

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Abstract Immunosuppressed patients are highly susceptible to invasive fungal infections (IFI) such as invasive pulmonary aspergillosis, which is predominantly caused by the fungus Aspergillus fumigatus. An important component of the fungal cell wall is chitin, a polymer of N-acetyl-D-glucosamine (GlcNAc). Chitin is not produced by humans, however, the chitin degrading enzymes (chitinases) chitotriosidase (Chit-1) and acidic mammalian chitinase (AMCase) are. Chitinase is predominantly produced by activated macrophages, and may possibly aid in the defense against chitin-containing pathogens. We show that serum and bronchoalveolar lavage (BAL) chitinase levels are increased in patients with IFI, and in mice after pulmonary exposure to A. fumigatus conidia. Several different stimuli, including stimulation with chitin can lead to chitinase responses. In vitro stimulation of U937 human monocytes and RAW mouse macrophages with either chitin-particles (7-12 µm) or GlcNAc increased secreted and intracellular chitinase activity, the accumulation of intracellular Chit-1, and significantly increased the mRNA levels of Chit-1 and AMCase. Accordingly, we hypothesize that Chit-1 expression is regulated through a positive feedback mechanism involving the degradation of chitin to GlcNAc by host chitinases and GlcNAc recognition that in turn upregulates chitinase expression. This potential feedback mechanism of chitinase regulation may have utility in the diagnosis of IFIs.

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Mazur, Marzena, Anna Zielińska, Marcin M. Grzybowski, Jacek Olczak e Jakub Fichna. "Chitinases and Chitinase-Like Proteins as Therapeutic Targets in Inflammatory Diseases, with a Special Focus on Inflammatory Bowel Diseases". International Journal of Molecular Sciences 22, n.º 13 (28 de junho de 2021): 6966. http://dx.doi.org/10.3390/ijms22136966.

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Chitinases belong to the evolutionarily conserved glycosyl hydrolase family 18 (GH18). They catalyze degradation of chitin to N-acetylglucosamine by hydrolysis of the β-(1-4)-glycosidic bonds. Although mammals do not synthesize chitin, they possess two enzymatically active chitinases, i.e., chitotriosidase (CHIT1) and acidic mammalian chitinase (AMCase), as well as several chitinase-like proteins (YKL-40, YKL-39, oviductin, and stabilin-interacting protein). The latter lack enzymatic activity but still display oligosaccharides-binding ability. The physiologic functions of chitinases are still unclear, but they have been shown to be involved in the pathogenesis of various human fibrotic and inflammatory disorders, particularly those of the lung (idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, sarcoidosis, and asthma) and the gastrointestinal tract (inflammatory bowel diseases (IBDs) and colon cancer). In this review, we summarize the current knowledge about chitinases, particularly in IBDs, and demonstrate that chitinases can serve as prognostic biomarkers of disease progression. Moreover, we suggest that the inhibition of chitinase activity may be considered as a novel therapeutic strategy for the treatment of IBDs.

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Dessens, Johannes T., Jacqui Mendoza, Charles Claudianos, Joseph M. Vinetz, Emad Khater, Stuart Hassard, Gaya R. Ranawaka e Robert E. Sinden. "Knockout of the Rodent Malaria Parasite Chitinase PbCHT1 Reduces Infectivity to Mosquitoes". Infection and Immunity 69, n.º 6 (1 de junho de 2001): 4041–47. http://dx.doi.org/10.1128/iai.69.6.4041-4047.2001.

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ABSTRACT During mosquito transmission, malaria ookinetes must cross a chitin-containing structure known as the peritrophic matrix (PM), which surrounds the infected blood meal in the mosquito midgut. In turn, ookinetes produce multiple chitinase activities presumably aimed at disrupting this physical barrier to allow ookinete invasion of the midgut epithelium. Plasmodium chitinase activities are demonstrated targets for human and avian malaria transmission blockade with the chitinase inhibitor allosamidin. Here, we identify and characterize the first chitinase gene of a rodent malaria parasite,Plasmodium berghei. We show that the gene, namedPbCHT1, is a structural ortholog ofPgCHT1 of the avian malaria parasite Plasmodium gallinaceum and a paralog of PfCHT1 of the human malaria parasite Plasmodium falciparum. Targeted disruption of PbCHT1 reduced parasite infectivity inAnopheles stephensi mosquitoes by up to 90%. Reductions in infectivity were also observed in ookinete feeds—an artificial situation where midgut invasion occurs before PM formation—suggesting that PbCHT1 plays a role other than PM disruption. PbCHT1 null mutants had no residual ookinete-derived chitinase activity in vitro, suggesting that P. berghei ookinetes express only one chitinase gene. Moreover, PbCHT1 activity appeared insensitive to allosamidin inhibition, an observation that raises questions about the use of allosamidin and components like it as potential malaria transmission-blocking drugs. Taken together, these findings suggest a fundamental divergence among rodent, avian, and human malaria parasite chitinases, with implications for the evolution ofPlasmodium-mosquito interactions.

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Suzuki, Masako, Wakako Fujimoto, Marie Goto, Masami Morimatsu, Bunei Syuto e Toshihiko Iwanaga. "Cellular Expression of Gut Chitinase mRNA in the Gastrointestinal Tract of Mice and Chickens". Journal of Histochemistry & Cytochemistry 50, n.º 8 (agosto de 2002): 1081–89. http://dx.doi.org/10.1177/002215540205000810.

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Recently, the second mammalian chitinase, designated acidic mammalian chitinase (AMCase), has been identified in human, mouse, and cow. In contrast to the earlier identified macrophage-derived chitinase (chitotriosidase), this chitinase is richly expressed in the gastrointestinal (GI) tract, suggesting its role in digestion of chitin-containing foods as well as defense against chitin-coated microorganisms and parasites. This in situ hybridization study first revealed cellular localization of the gut-type chitinase in the mouse and chicken. In adult mice, the parotid gland, von Ebner's gland, and gastric chief cells, all of which are exocrine cells of the serous type, expressed the gut chitinase mRNA. In the chicken, oxyntico-peptic cells in glandular stomach (proventriculus) and hepatocytes expressed the chitinase mRNA. Because cattle produce the gut chitinase (chitin-binding protein b04) only in the liver, the gut chitinases in mammals and birds have three major sources of production, i.e., the salivary gland, stomach, and liver. During ontogenetic development, the expression level in the parotid gland and stomach of mice increased to the adult level before weaning, whereas in the stomach of chickens intense signals were detectable in embryos from incubation day 7.

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Tachu, Babila, Smitha Pillai, Richard Lucius e Thomas Pogonka. "Essential Role of Chitinase in the Development of the Filarial Nematode Acanthocheilonema viteae". Infection and Immunity 76, n.º 1 (15 de outubro de 2007): 221–28. http://dx.doi.org/10.1128/iai.00701-07.

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ABSTRACT Chitinases of pathogens have been proposed as potential targets of vaccines or specific inhibitors. We studied the genomic organization, transcript levels, developmental expression, and biological function of chitinases in the rodent filarial nematode Acanthocheilonema viteae, a model organism for human-pathogenic filarial worms. Characterization of nine genomic clones from an A. viteae phage library and Southern blot experiments revealed the existence of three different chitinase genes, two of which could theoretically yield functional transcripts. The deduced proteins of these genes had the common modular organization of family 18 chitinases. Northern blot experiments and rapid amplification of cDNA ends-PCR with adult worms and larval stages showed that only one gene is expressed, with high variation in transcript levels, as determined by real-time PCR. Chitinase transcript levels were lowest in the late male stage 4 larva (L4) and peaked in the stage 3 larva (L3), which was corroborated by Western blotting. RNA interference (RNAi) experiments showed that treatment of L3 and adult female worms with double-stranded RNA of chitinase inhibited molting of L3 worms and hatching of microfilariae. RNAi also led to the death of 50% of female worms, revealing the essential role of chitinase in the life cycle of filarial nematodes.

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Schlein, Y., e R. L. Jacobson. "Haemoglobin inhibits the development of infective promastigotes and chitinase secretion inLeishmania majorcultures". Parasitology 109, n.º 1 (julho de 1994): 23–28. http://dx.doi.org/10.1017/s0031182000077726.

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SUMMARYHaemoglobin or blood in the growth medium ofLeishmania majorinhibited the formation of infective promastigotes and the secretion of chitinases. Inoculation of mice with stationary-phase parasites from control medium caused infections in 20/29 mice, compared to 3/20 mice injected with parasites grown with 10% rabbit blood, or 1/30 mice that received parasites grown with rabbit haemoglobin. The concentration of peanut lectin (PNA) required to agglutinate promastigotes was used as an index of their infectivity, ranging from a high concentration for infective populations to a low concentration for relatively non-infective populations. Agglutination of 50% of the parasites from control medium or from medium containing rabbit haemoglobin required 4·1 μg PNA/ml and 0·1 μg PNA/ml, respectively. Chitinase activities/107parasites decreased from 4·8 units chitinase and 12·5 unitsN-acetylglucosaminidase (NAGase) in the control to 2·0 units chitinase and 8·5 units NAGase in cultures containing rabbit haemoglobin. Rabbit, human, bovine and pigeon haemoglobins had various inhibitory effects on the activity of chitinases and not on the virulence, as expressed by PNA agglutination. The relevance of the results to the cycle ofLeishmaniais discussed.

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Fadel, Firas, Yuguang Zhao, Alexandra Cousido-Siah, Eduardo Howard, André Mitschler e Alberto Podjarny. "Structural and mechanistic studies of human chitinase". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 de agosto de 2014): C445. http://dx.doi.org/10.1107/s2053273314095540.

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Chitinases are enzymes that hydrolyze chitin, a glucosamine polymer synthesized by lower organisms for structural purposes [1]. While humans do not synthetize chitin, they express two active chitinases, Chitotriosidase (hCHIT1) and Acidic Mammalian Chitinase (hAMCase). Both enzymes attracted attention due to their upregulation in immune system disorders [2,3]. They consist of a catalytic domain of 39 kDa and a chitin binding domain, joined by a hinge. The active site shows a cluster of three conserved acidic residues, E140, D138 and D136, linked by H-bonds, where D138 and E140 are involved in the hydrolysis reaction [1,3]. To increase our knowledge on the catalytic mechanism of human chitinases, we conducted a detailed structural analysis on hCHIT1. For this, we have improved the X-ray resolution of the apo hCHIT1 catalytic domain to 1Å. We investigated the protonation state on the catalytic site and detected a double conformation of D138, one in contact with D136 and a second one in contact with E140. Our analysis revealed for the first time different protonation states for each conformation of D138 (fig1). Interestingly, our X-ray data suggest that the catalytic E140, supposed to donate a proton in the catalytic reaction, is deprotonated in the apo form. To gain insight on the proton transition pathway during the hydrolysis, we have solved the X-ray structure of hCHIT1 complexed with the substrate at 1.05 Å. In comparison with the apo form, this structure shows a rearrangement of the protonation states of the catalytic triad triggered by the binding of the substrate. Our results led us to suggest a new hydrolysis model involving changes in the hydrogen bond network of the catalytic triad accompanied by a flip of D138 towards D136. This contributes to protonate E140, which then donates the proton to the substrate. To confirm the role of the active site's hydrogen network, we are currently studying CHIT1 by neutron crystallography and quantum mechanics.

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Vega, Karina, e Markus Kalkum. "Chitin, Chitinase Responses, and Invasive Fungal Infections". International Journal of Microbiology 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/920459.

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The human immune system is capable of recognizing and degrading chitin, an important cell wall component of pathogenic fungi. In the context of host-immune responses to fungal infections, herein we review the particular contributions and interplay of fungus and chitin recognition, and chitin-degrading enzymes, known as chitinases. The mechanisms of host chitinase responses may have implications for diagnostic assays as well as novel therapeutic approaches for patients that are at risk of contracting fatal fungal infections.

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Iershov, Anton, Konstantin Odynets, Alexander Kornelyuk e Vadim Kavsan. "Homology modeling of 3D structure of human chitinase-like protein CHI3L2". Open Life Sciences 5, n.º 4 (1 de agosto de 2010): 407–20. http://dx.doi.org/10.2478/s11535-010-0039-8.

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AbstractThe human genome encodes six proteins of family 18 glycosyl hydrolases, two active chitinases and four chitinase-like lectins (chi-lectins) lacking catalytic activity. The present article is dedicated to homology modeling of 3D structure of human chitinase 3-like 2 protein (CHI3L2), which is overexpressed in glial brain tumors, and its structural comparison with homologous chi-lectin CHI3L1. Two crystal structures of CHI3L1 in free state (Protein Data Bank codes 1HJX and 1NWR) were used as structural templates for the homology modeling by Modeller 9.7 program, and the best quality model structure was selected from the obtained model ensemble. Analysis of potential oligosaccharide-binding groove structures of CHI3L1 and CHI3L2 revealed significant differences between these two homologous proteins. 8 of 19 amino acid residues important for ligand binding are substituted in CHI3L2: Tyr34/Asp39, Trp69/Lys74, Trp71/Lys76, Trp99/Tyr104, Asn100/Leu105, Met204/Leu210, Tyr206/Phe212 and Arg263/His271. The differences between these residues could influence the structure of the ligand-binding groove and substantially change the ability of CHI3L2 to bind oligosaccharide ligands.

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Rathore, Abhishek Singh, e Rinkoo D. Gupta. "Chitinases from Bacteria to Human: Properties, Applications, and Future Perspectives". Enzyme Research 2015 (19 de novembro de 2015): 1–8. http://dx.doi.org/10.1155/2015/791907.

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Chitin is the second most plenteous polysaccharide in nature after cellulose, present in cell walls of several fungi, exoskeletons of insects, and crustacean shells. Chitin does not accumulate in the environment due to presence of bacterial chitinases, despite its abundance. These enzymes are able to degrade chitin present in the cell walls of fungi as well as the exoskeletons of insect. They have shown being the potential agents for biological control of the plant diseases caused by various pathogenic fungi and insect pests and thus can be used as an alternative to chemical pesticides. There has been steady increase in demand of chitin derivatives, obtained by action of chitinases on chitin polymer for various industrial, clinical, and pharmaceutical purposes. Hence, this review focuses on properties and applications of chitinases starting from bacteria, followed by fungi, insects, plants, and vertebrates. Designing of chitinase by applying directed laboratory evolution and rational approaches for improved catalytic activity for cost-effective field applications has also been explored.

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Kzhyshkowska, Julia, Alexei Gratchev e Sergij Goerdt. "Human Chitinases and Chitinase-Like Proteins as Indicators for Inflammation and Cancer". Biomarker Insights 2 (janeiro de 2007): 117727190700200. http://dx.doi.org/10.1177/117727190700200023.

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Human Glyco_18 domain-containing proteins constitute a family of chitinases and chitinase-like proteins. Chitotriosidase and AMCase are true enzymes which hydrolyse chitin and have a C-terminal chitin-binding domain. YKL-40, YKL-39, SI-CLP and murine YM1/2 proteins possess solely Glyco_18 domain and do not have the hydrolytic activity. The major sources of Glyco_18 containing proteins are macrophages, neutrophils, epithelial cells, chondrocytes, synovial cells, and cancer cells. Both macrophages and neutrophils use the regulated secretory mechanism for the release of Glyco_18 containing proteins. Glyco_18 containing proteins are established biomarkers for human diseases. Chitotriosidase is overproduced by lipid-laden macrophages and is a major marker for the inherited lysosomal storage Gaucher disease. AMCase and murine lectin YM1 are upregulated in Th2-environment, and enzymatic activity of AMCase contributes to asthma pathogenesis. YKL proteins act as soluble mediators for the cell proliferation and migration, and are also involved in rheumatoid arthritis, inflammatory bowel disease, hepatic fibrosis and cirrhosis. Chitotriosidase and YKL-40 reflect the macrophage activation in atherosclerotic plaques. Serum level of YKL-40 is a diagnostic and prognostic marker for numerous types of solid tumors. YKL-39 is a marker for the activation of chondrocytes and the progression of the osteoarthritis in human. Recently identified SI-CLP is upregulated by Th2 cytokine IL-4 as well as by glucocorticoids. This unique feature of SI-CLP makes it an attractive candidate for the examination of individual sensitivity of patients to glucocorticoid treatment and prediction of side effects of glucocorticoid therapy. Human chitinases and chitinase-like proteins are found in tissues and circulation, and can be detected by non-invasive technologies.

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Chandra, Kasturi, Atish Roy Chowdhury, Ritika Chatterjee e Dipshikha Chakravortty. "GH18 family glycoside hydrolase Chitinase A of Salmonella enhances virulence by facilitating invasion and modulating host immune responses". PLOS Pathogens 18, n.º 4 (28 de abril de 2022): e1010407. http://dx.doi.org/10.1371/journal.ppat.1010407.

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Salmonella is a facultative intracellular pathogen that has co-evolved with its host and has also developed various strategies to evade the host immune responses. Salmonella recruits an array of virulence factors to escape from host defense mechanisms. Previously chitinase A (chiA) was found to be upregulated in intracellular Salmonella. Although studies show that several structurally similar chitinases and chitin-binding proteins (CBP) of many human pathogens have a profound role in various aspects of pathogenesis, like adhesion, virulence, and immune evasion, the role of chitinase in the intravacuolar pathogen Salmonella has not yet been elucidated. Therefore, we made chromosomal deletions of the chitinase encoding gene (chiA) to study the role of chitinase of Salmonella enterica in the pathogenesis of the serovars, Typhimurium, and Typhi using in vitro cell culture model and two different in vivo hosts. Our data indicate that ChiA removes the terminal sialic acid moiety from the host cell surface, and facilitates the invasion of the pathogen into the epithelial cells. Interestingly we found that the mutant bacteria also quit the Salmonella-containing vacuole and hyper-proliferate in the cytoplasm of the epithelial cells. Further, we found that ChiA aids in reactive nitrogen species (RNS) and reactive oxygen species (ROS) production in the phagocytes, leading to MHCII downregulation followed by suppression of antigen presentation and antibacterial responses. Notably, in the murine host, the mutant shows compromised virulence, leading to immune activation and pathogen clearance. In continuation of the study in C. elegans, Salmonella Typhi ChiA was found to facilitate bacterial attachment to the intestinal epithelium, intestinal colonization, and persistence by downregulating antimicrobial peptides. This study provides new insights on chitinase as an important and novel virulence determinant that helps in immune evasion and increased pathogenesis of Salmonella.

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HOUSTON, Douglas R., Ian EGGLESTON, Bj⊘rnar SYNSTAD, Vincent G. H. EIJSINK e Daan M. F. van AALTEN. "The cyclic dipeptide CI-4 [cyclo-(l-Arg-d-Pro)] inhibits family 18 chitinases by structural mimicry of a reaction intermediate". Biochemical Journal 368, n.º 1 (15 de novembro de 2002): 23–27. http://dx.doi.org/10.1042/bj20021034.

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Family 18 chitinases are attractive targets for the development of new inhibitors with chemotherapeutic potential against fungi, insects and protozoan/nematodal parasites. Although several inhibitors have been identified, these are based on complex chemistry, which hampers iterative structure-based optimization. Here we report the details of chitinase inhibition by the natural product peptide CI-4 [cyclo-(l-Arg-d-Pro)], which possesses activity against the human pathogenic fungus Candida albicans, and describe a 1.7Å (0.17nm) crystal structure of CI-4 in complex with the enzyme. The structure reveals that the cyclic dipeptide inhibits chitinases by structurally mimicking a reaction intermediate, and could, on the basis of its accessible chemistry, be a candidate for further optimization.

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Marbán-González, Alberto, Armando Hernández-Mendoza, Mario Ordóñez, Rodrigo Said Razo-Hernández e José Luis Viveros-Ceballos. "Discovery of Octahydroisoindolone as a Scaffold for the Selective Inhibition of Chitinase B1 from Aspergillus fumigatus: In Silico Drug Design Studies". Molecules 26, n.º 24 (15 de dezembro de 2021): 7606. http://dx.doi.org/10.3390/molecules26247606.

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Chitinases represent an alternative therapeutic target for opportunistic invasive mycosis since they are necessary for fungal cell wall remodeling. This study presents the design of new chitinase inhibitors from a known hydrolysis intermediate. Firstly, a bioinformatic analysis of Aspergillus fumigatus chitinase B1 (AfChiB1) and chitotriosidase (CHIT1) by length and conservation was done to obtain consensus sequences, and molecular homology models of fungi and human chitinases were built to determine their structural differences. We explored the octahydroisoindolone scaffold as a potential new antifungal series by means of its structural and electronic features. Therefore, we evaluated several synthesis-safe octahydroisoindolone derivatives by molecular docking and evaluated their AfChiB1 interaction profile. Additionally, compounds with the best interaction profile (1–5) were docked within the CHIT1 catalytic site to evaluate their selectivity over AfChiB1. Furthermore, we considered the interaction energy (MolDock score) and a lipophilic parameter (aLogP) for the selection of the best candidates. Based on these descriptors, we constructed a mathematical model for the IC50 prediction of our candidates (60–200 μM), using experimental known inhibitors of AfChiB1. As a final step, ADME characteristics were obtained for all the candidates, showing that 5 is our best designed hit, which possesses the best pharmacodynamic and pharmacokinetic character.

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Reichard, Utz, Chiung-Yu Hung, Pei W. Thomas e Garry T. Cole. "Disruption of the Gene Which Encodes a Serodiagnostic Antigen and Chitinase of the Human Fungal PathogenCoccidioides immitis". Infection and Immunity 68, n.º 10 (1 de outubro de 2000): 5830–38. http://dx.doi.org/10.1128/iai.68.10.5830-5838.2000.

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ABSTRACT Disruption of genes in medically important fungi has proved to be a powerful tool for evaluation of putative virulence factors and identification of potential protein targets for novel antifungal drugs. Chitinase has been suggested to play a pivotal role in autolysis of the parasitic cell wall of Coccidioides immitis during the asexual reproductive cycle (endosporulation) of this systemic pathogen. Two chitinase genes (CTS1 and CTS2) of C. immitis have been cloned. Preliminary evidence has suggested that expression of CTS1 is markedly increased during endospore formation. The secreted CTS1 chitinase has also been shown to react with patient anti-Coccidioides complement-fixing (CF) antibody and is a valuable aid in the serodiagnosis of coccidioidomycosis. To examine the role of CTS1 in the morphogenesis of parasitic cells, the CTS1 gene was disrupted by a single, locus-specific crossover event. This resulted in homologous integration of a pAN7.1 plasmid construct that contained a 1.1-kb fragment of the chitinase gene into the chromosomal DNA of C. immitis. Results of Southern hybridizations, immunoblot analyses of culture filtrates using both CTS1-specific murine antiserum and serum from a patient with confirmed coccidioidal infection, an immunodiffusion test for CF antigenicity, and substrate gel electrophoresis assays of chitinase activity confirmed that the CTS1 gene was disrupted and nonfunctional. This is the first report of a successful targeted gene disruption in C. immitis. However, loss ofCTS1 function had no effect on virulence or endosporulation. Comparative assays of chitinase activity in the parental and Δcts1 strains suggested that the absence of a functional CTS1 gene can be compensated for by elevated expression of the CTS2 gene. Current investigations are focused on disruption of CTS2 in the Δcts1host to further evaluate the significance of chitinase activity in the parasitic cycle of C. immitis.

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Escott, G. M., e D. J. Adams. "Chitinase activity in human serum and leukocytes." Infection and immunity 63, n.º 12 (1995): 4770–73. http://dx.doi.org/10.1128/iai.63.12.4770-4773.1995.

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Gratchev, A. N., D. V. Samoilova, S. N. Kurochkin e O. V. Kovaleva. "Development of a novel monoclonal antibody against chitinase-like protein YKL-39 applicable for immunohistochemistry". Russian Journal of Biotherapy 18, n.º 2 (15 de junho de 2019): 27–31. http://dx.doi.org/10.17650/1726-9784-2019-18-2-27-31.

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Introduction. Mammalian chitinase-like proteins are produced in the areas of inflammation and in tumors. Some members of chitinase-like proteins family are studied as potential biomarkers of tumors (glioma, prostate and ovary). YKL-39 also known as chitinase-3-like 2 (CHI3L2) is a secreted protein produced by chondrocytes. Its high expression is also found in synoviocytes, lung heart and macrophages.The aim of this study was the development of highly specific monoclonal antibodies against human YKL-39. Materials and methods. Using recombinant full-length human YKL-39 as immunogen using hybridoma technology we have generated monoclonal antibody 1B2G4, that specifically binds YKL-39 in ELISA.Results and conclusion. Obtained antibody was successfully tested in Western blot, immunocytochemistry, immunofluorescence and immunohistochemistry on FFPE sections. It was shown that the antibody binds the full-length YKL-39 protein and does not interact with other chitinase-like proteins.

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Kzhyshkowska, Julia, Srinivas Mamidi, Alexei Gratchev, Elisabeth Kremmer, Christina Schmuttermaier, Liis Krusell, Georg Haus et al. "Novel stabilin-1 interacting chitinase-like protein (SI-CLP) is up-regulated in alternatively activated macrophages and secreted via lysosomal pathway". Blood 107, n.º 8 (15 de abril de 2006): 3221–28. http://dx.doi.org/10.1182/blood-2005-07-2843.

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Abstract Mammalian Glyco_18-domain–containing proteins include catalytically active chitinases and chitinase-like proteins with cytokine activity involved in host defense and Th2-type inflammatory reactions. Here, we describe a novel human Glyco_18-domain–containing protein, SI-CLP, as an interacting partner of the endocytic/sorting receptor stabilin-1. Similarly to the chitinase-like cytokines YKL-39, YKL-40, and YM1/2, SI-CLP lacks a chitin-binding domain and catalytic amino acids. Using a novel mAb 1C11, we demonstrated that SI-CLP is sorted into late endosomes and secretory lysosomes in human alternatively activated macrophages. The direct interaction of SI-CLP with stabilin-1, their colocalization in the trans-Golgi network, and the reduced sorting of SI-CLP into lysosomes in macrophages treated with stabilin-1 siRNA suggest that stabilin-1 is involved in intracellular sorting of SI-CLP. Expression of SI-CLP in macrophages was strongly up-regulated by the Th2 cytokine IL-4 and by dexamethasone. This effect was suppressed by IFNγ but not affected by IL-10. In contrast, expression of YKL-40 was induced by IFNγ and suppressed by dexamethasone. Macrophages treated with IL-4 secreted SI-CLP, while costimulation with dexamethasone blocked secretion and resulted in intracellular accumulation of SI-CLP. The 1C11 mAb detected SI-CLP in human bronchoalveolar lavage and peripheral-blood leukocytes (PBLs), and can be used to analyze the role of SI-CLP in human disorders.

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Chou, Yi-Te, Shihua Yao, Robert Czerwinski, Margaret Fleming, Rustem Krykbaev, Dejun Xuan, Huanfang Zhou et al. "Kinetic Characterization of Recombinant Human Acidic Mammalian Chitinase". Biochemistry 45, n.º 14 (abril de 2006): 4444–54. http://dx.doi.org/10.1021/bi0525977.

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Cordeiro, Rossana Aguiar, Valdirene Moreira Gomes, Ana Fontenele Urano Carvalho e Vânia Maria Maciel Melo. "Effect of proteins from the red seaweed Hypnea musciformis (Wulfen) Lamouroux on the growth of human pathogen yeasts". Brazilian Archives of Biology and Technology 49, n.º 6 (novembro de 2006): 915–21. http://dx.doi.org/10.1590/s1516-89132006000700008.

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A protein fraction, rich in lectin, obtained from the red seaweed Hypnea musciformis by precipitation with ammonium sulfate (F40/70) was screened for chitinase and beta-1,3-glucanase activity and assessed for antifungal potential against the human pathogen yeasts Candida albicans and C. guilliermondii. The F40/70 fraction showed chitinase and beta-1,3-glucanase enzymes, with specific activities of 276.43 and 1880.7 Units.mg -1 protein, respectively. It was capable of inhibiting the growth of C. guilliermondii at the concentrations of 45, 100 and 450 µg protein.ml -1 but it showed only a discrete inhibition against C. albicans irrespective of the tested concentrations. The inhibitory action was shown to be fungistatic and the presence of the glycoprotein fetuin, for which the lectin in the fraction had affinity, abolished the antifungal action. The complete growth recovery following fetuin treatment indicated that chitinase and beta-1,3-glucanase were not involved in the growth inhibition of these yeasts.

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Dohnálek, Jan, Jarmila Dušková, Galina Tishchenko, Petr Kolenko, Tereza Skálová, Petr Novák, Karla Fejfarová e Jiří Šimůnek. "Chitinase Chit62J4 Essential for Chitin Processing by Human Microbiome Bacterium Clostridium paraputrificum J4". Molecules 26, n.º 19 (2 de outubro de 2021): 5978. http://dx.doi.org/10.3390/molecules26195978.

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Commensal bacterium Clostridium paraputrificum J4 produces several extracellular chitinolytic enzymes including a 62 kDa chitinase Chit62J4 active toward 4-nitrophenyl N,N′-diacetyl-β-d-chitobioside (pNGG). We characterized the crude enzyme from bacterial culture fluid, recombinant enzyme rChit62J4, and its catalytic domain rChit62J4cat. This major chitinase, securing nutrition of the bacterium in the human intestinal tract when supplied with chitin, has a pH optimum of 5.5 and processes pNGG with Km = 0.24 mM and kcat = 30.0 s−1. Sequence comparison of the amino acid sequence of Chit62J4, determined during bacterial genome sequencing, characterizes the enzyme as a family 18 glycosyl hydrolase with a four-domain structure. The catalytic domain has the typical TIM barrel structure and the accessory domains—2x Fn3/Big3 and a carbohydrate binding module—that likely supports enzyme activity on chitin fibers. The catalytic domain is highly homologous to a single-domain chitinase of Bacillus cereus NCTU2. However, the catalytic profiles significantly differ between the two enzymes despite almost identical catalytic sites. The shift of pI and pH optimum of the commensal enzyme toward acidic values compared to the soil bacterium is the likely environmental adaptation that provides C. paraputrificum J4 a competitive advantage over other commensal bacteria.

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Gouda, Hiroaki, Shinichi Terashima, Kanami Iguchi, Akihiro Sugawara, Yoshifumi Saito, Tsuyoshi Yamamoto, Tomoyasu Hirose, Kazuro Shiomi, Toshiaki Sunazuka e Satoshi Ōmura. "Molecular modeling of human acidic mammalian chitinase in complex with the natural-product cyclopentapeptide chitinase inhibitor argifin". Bioorganic & Medicinal Chemistry 17, n.º 17 (1 de setembro de 2009): 6270–78. http://dx.doi.org/10.1016/j.bmc.2009.07.045.

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Paoletti, Maurizio G., Lorenzo Norberto, Roberta Damini e Salvatore Musumeci. "Human Gastric Juice Contains Chitinase That Can Degrade Chitin". Annals of Nutrition and Metabolism 51, n.º 3 (2007): 244–51. http://dx.doi.org/10.1159/000104144.

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Yoo, Yeeun, e Hyoung T. Choi. "Antifungal chitinase against human pathogenic yeasts from Coprinellus congregatus". Journal of Microbiology 52, n.º 5 (17 de fevereiro de 2014): 441–43. http://dx.doi.org/10.1007/s12275-014-3257-3.

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Bakri, Marwah M., Aisha M. H. Al-Rajhi, Emad Abada, Olfat M. A. Salem, Abdel-Rahman M. Shater, Mohamed S. Mahmoud e Tarek M. Abdel Ghany. "Mycostimulator of chitinolytic activity: Thermodynamic studies and its activity against human and food-borne microbial pathogens". BioResources 17, n.º 3 (1 de junho de 2022): 4378–94. http://dx.doi.org/10.15376/biores.17.3.4378-4394.

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Chitinolytic activity and antibiosis are gaining prominence in various biotechnological fields. Dead fungal biomass (DFB) was used as a mycostimulator of chitinase production and antibiosis by Aspergillus fumigatus. The presence of DFB stimulated the synthesis of various secondary metabolites by A. fumigatus that were detected by gas chromatography-mass spectrometry analysis such as 6,8-Di-C-á-glucosylluteolin; bistrimethylsilyl N-acetyl eicosasphinga-4,11-dienine; curan-17-oic acid, 19,20-dihydroxy-, methyl ester, (19S)-; spiro[5à-androstane-3,2′-thiazolidine; retinal; Androsta-1,4-dien-3-one; Panaxydol; Costunolide; Cyclo-(glycyl-L-tyrosyl); and 2-amino ethane thiolsulfuric acid. Chitinase activity was 42.9 Units/mL with the presence DFB, where it was 10.3 Units/mL without DFB. The maximum activity of chitinase was observed at 1.5 g of dead fungal biomass, at 4 h, 50 °C and pH 6. Thermodynamic properties showed ∆H° and ∆S° values of 126 KJ mol-1 and 432 J mol-1 K-1, respectively, indicating an endothermic reaction up to 60 °C. Deviation in ∆G° values confirmed that the reaction at 10 to 20 °C is a nonspontaneous reaction, and at 30 to 60 °C the reaction has a spontaneous nature. DFB encouraged the antimicrobial activity against Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Aspergillus fumigatus, Mucor circinelloides, and Candida albicans with 2.3, 2.2, 2.8, 0.8, 0.7, and 2.2 mm inhibition zones, respectively.

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Pantoom, Supansa, Ingrid R. Vetter, Heino Prinz e Wipa Suginta. "Potent Family-18 Chitinase Inhibitors". Journal of Biological Chemistry 286, n.º 27 (29 de abril de 2011): 24312–23. http://dx.doi.org/10.1074/jbc.m110.183376.

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Six novel inhibitors of Vibrio harveyi chitinase A (VhChiA), a family-18 chitinase homolog, were identified by in vitro screening of a library of pharmacologically active compounds. Unlike the previously identified inhibitors that mimicked the reaction intermediates, crystallographic evidence from 14 VhChiA-inhibitor complexes showed that all of the inhibitor molecules occupied the outer part of the substrate-binding cleft at two hydrophobic areas. The interactions at the aglycone location are well defined and tightly associated with Trp-397 and Trp-275, whereas the interactions at the glycone location are patchy, indicating lower affinity and a loose interaction with two consensus residues, Trp-168 and Val-205. When Trp-275 was substituted with glycine (W275G), the binding affinity toward all of the inhibitors dramatically decreased, and in most structures two inhibitor molecules were found to stack against Trp-397 at the aglycone site. Such results indicate that hydrophobic interactions are important for binding of the newly identified inhibitors by the chitinase. X-ray data and isothermal microcalorimetry showed that the inhibitors occupied the active site of VhChiA in three different binding modes, including single-site binding, independent two-site binding, and sequential two-site binding. The inhibitory effect of dequalinium in the low nanomolar range makes this compound an extremely attractive lead compound for plausible development of therapeutics against human diseases involving chitinase-mediated pathologies.

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Kzhyshkowska, Julia, Shuiping Yin, Tengfei Liu, Vladimir Riabov e Irina Mitrofanova. "Role of chitinase-like proteins in cancer". Biological Chemistry 397, n.º 3 (1 de março de 2016): 231–47. http://dx.doi.org/10.1515/hsz-2015-0269.

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Abstract Chitinase-like proteins (CLPs) are lectins combining properties of cytokines and growth factors. Human CLPs include YKL-40, YKL-39 and SI-CLP that are secreted by cancer cells, macrophages, neutrophils, synoviocytes, chondrocytes and other cells. The best investigated CLP in cancer is YKL-40. Serum and plasma levels of YKL-40 correlate with poor prognosis in breast, lung, prostate, liver, bladder, colon and other types of cancers. In combination with other circulating factors YKL-40 can be used as a predictive biomarker of cancer outcome. In experimental models YKL-40 supports tumor initiation through binding to RAGE, and is able to induce cancer cell proliferation via ERK1/2-MAPK pathway. YKL-40 supports tumor angiogenesis by interaction with syndecan-1 on endothelial cells and metastatic spread by stimulating production of pro-inflammatory and pro-invasive factors MMP9, CCL2 and CXCL2. CLPs induce production of pro- and anti-inflammatory cytokines and chemokines, and are potential modulators of inflammatory tumor microenvironment. Targeting YKL-40 using neutralizing antibodies exerts anti-cancer effect in preclinical animal models. Multifunctional role of CLPs in regulation of inflammation and intratumoral processes makes them attractive candidates for tumor therapy and immunomodulation. In this review we comprehensively analyze recent data about expression pattern, and involvement of human CLPs in cancer.

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Cole, Garry T., Elizabeth J. Pishko e Kalpathi R. Seshan. "Possible roles of wall hydrolases in the morphogenesis of Coccidioides immitis". Canadian Journal of Botany 73, S1 (31 de dezembro de 1995): 1132–41. http://dx.doi.org/10.1139/b95-369.

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We have used the human respiratory pathogen, Coccidioides immitis, as an experimental model to explore possible interrelationships of wall-associated hydrolases, cell growth, and reproduction. Preliminary evidence has been presented that suggests that certain wall hydrolases (glucanase, chitinase) may play key roles in cell development in this systemic pathogen. Initial differentiation of the parasitic cells from cylindrical arthroconidia involves a period of isotropic growth and results in formation of a multinucleate spherule (approximately 60 μm diameter). An endo-1,3-β-glucanase that may participate in this diametric growth phase has been isolated. Two distinct chitinase genes (cts1, cts2) have been isolated from C. immitis and shown to be members of different classes of this wall hydrolase. The class I chitinase (CTS2) demonstrates homology to a reported endochitinase of Saccharomyces cerevisiae that has been shown to be essential for yeast daughter cell release. CTS2 may play a pivotal role in isotropic growth, as well as differentiation and release of endospores from maternal spherules. In the absence of specific gene disruption and transformation experiments, these data are still circumstantial evidence for the functions of wall hydrolases in C. immitis development. However, we suggest our results provide further support for the concept that wall hydrolases represent rational molecular targets for future development of novel antifungal agents. Key words: Coccidioides, cell wall, β-glucanase, chitinase, morphogenesis.

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Tyurin, YU A., E. O. Sukmanskaya, S. N. Kulikov e R. S. Fassakhov. "Chitinase-like protein YKL-40 from nasal mucosa as a biomarker of allergic rhinitis". Russian Journal of Allergy 9, n.º 4 (15 de dezembro de 2012): 13–17. http://dx.doi.org/10.36691/rja677.

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Background. Chitinase-like protein YKL-40 plays an important role in human atopic diseases. The aim of this study was to determine of the level of chitinase-like protein YKL-40 in the secretions of nasal mucosa of patients with chronic allergic rhinitis. Methods. Samples of allergic nasal mucosa were obtained from twelve patients with perennial allergic rhinitis. Measurement of nasal YKL-40 levels was performed with modification in duplicate using commercially available ELISA kits for YKL-40. The amount of nasal eosinophils and neutrophils were also determined. Results. There were significant differences between healthy volunteers and patients with allergic rhinitis for mucosal YKL-40 levels and the amount of nasal eosinophil and neutrophil cells, which have some characteristics closely associated with allergic response. The nasal YKL-40 levels in patients with allergic rhinitis were in tens times more higher than those in controls. Conclusion. Thus, we conclude that the level of chitinase-like protein YKL-40 was upregulated in allergic nasal mucosa compared with normal nasal mucosa, suggesting their roles in the pathogenesis of allergic rhinitis.

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Hong, Jeong Hee, Jung Yeon Hong, Boryung Park, Syng-Ill Lee, Jeong Taeg Seo, Kyu-Earn Kim, Myung Hyun Sohn e Dong Min Shin. "Chitinase Activates Protease-Activated Receptor-2 in Human Airway Epithelial Cells". American Journal of Respiratory Cell and Molecular Biology 39, n.º 5 (novembro de 2008): 530–35. http://dx.doi.org/10.1165/rcmb.2007-0410oc.

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Rao, Francesco V., Douglas R. Houston, Rolf G. Boot, Johannes M. F. G. Aerts, Shohei Sakuda e Daan M. F. Van Aalten. "Crystal Structures of Allosamidin Derivatives in Complex with Human Macrophage Chitinase". Journal of Biological Chemistry 278, n.º 22 (14 de março de 2003): 20110–16. http://dx.doi.org/10.1074/jbc.m300362200.

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Andryianau, Gleb, Michal Kowalski, Michal C. Piotrowicz, Adam A. Rajkiewicz, Barbara Dymek, Piotr L. Sklepkiewicz, Elzbieta Pluta et al. "Benzoxazepine-Derived Selective, Orally Bioavailable Inhibitor of Human Acidic Mammalian Chitinase". ACS Medicinal Chemistry Letters 11, n.º 6 (24 de abril de 2020): 1228–35. http://dx.doi.org/10.1021/acsmedchemlett.0c00092.

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Tjoelker, Larry W., Larry Gosting, Steve Frey, Christie L. Hunter, Hai Le Trong, Bart Steiner, Heather Brammer e Patrick W. Gray. "Structural and Functional Definition of the Human Chitinase Chitin-binding Domain". Journal of Biological Chemistry 275, n.º 1 (7 de janeiro de 2000): 514–20. http://dx.doi.org/10.1074/jbc.275.1.514.

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Boot, Rolf G., G. Herma Renkema, Anneke Strijland, Anton Jan van Zonneveld e Johannes M. F. G. Aerts. "Cloning of a cDNA Encoding Chitotriosidase, a Human Chitinase Produced by Macrophages". Journal of Biological Chemistry 270, n.º 44 (3 de novembro de 1995): 26252–56. http://dx.doi.org/10.1074/jbc.270.44.26252.

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Okawa, Kazuaki, Misa Ohno, Akinori Kashimura, Masahiro Kimura, Yuki Kobayashi, Masayoshi Sakaguchi, Yasusato Sugahara et al. "Loss and Gain of Human Acidic Mammalian Chitinase Activity by Nonsynonymous SNPs". Molecular Biology and Evolution 33, n.º 12 (4 de outubro de 2016): 3183–93. http://dx.doi.org/10.1093/molbev/msw198.

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HONG, J., K. LEE, K. KIM, H. JEE, M. SOHN e K. KIM. "Effect Of Chitinase On Il-8 Production In Human Respiratory Epithelial Cells". Journal of Allergy and Clinical Immunology 121, n.º 2 (fevereiro de 2008): S205. http://dx.doi.org/10.1016/j.jaci.2007.12.765.

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Dinkelaar, Jasper, Boudewijn A. Duivenvoorden, Tom Wennekes, Herman S. Overkleeft, Rolf G. Boot, Johannes M. F. G. Aerts, Jeroen D. C. Codée e Gijs A. van der Marel. "A Preparative Synthesis of Human Chitinase Fluorogenic Substrate (4′-Deoxychitobiosyl)-4-methylumbelliferone". European Journal of Organic Chemistry 2010, n.º 13 (maio de 2010): 2565–70. http://dx.doi.org/10.1002/ejoc.201000080.

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Colussi, Paul A., Charles A. Specht e Christopher H. Taron. "Characterization of a Nucleus-Encoded Chitinase from the Yeast Kluyveromyces lactis". Applied and Environmental Microbiology 71, n.º 6 (junho de 2005): 2862–69. http://dx.doi.org/10.1128/aem.71.6.2862-2869.2005.

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ABSTRACT Endogenous proteins secreted from Kluyveromyces lactis were screened for their ability to bind to or to hydrolyze chitin. This analysis resulted in identification of a nucleus-encoded extracellular chitinase (KlCts1p) with a chitinolytic activity distinct from that of the plasmid-encoded killer toxin α-subunit. Sequence analysis of cloned KlCTS1 indicated that it encodes a 551-amino-acid chitinase having a secretion signal peptide, an amino-terminal family 18 chitinase catalytic domain, a serine-threonine-rich domain, and a carboxy-terminal type 2 chitin-binding domain. The association of purified KlCts1p with chitin is stable in the presence of high salt concentrations and pH 3 to 10 buffers; however, complete dissociation and release of fully active KlCts1p occur in 20 mM NaOH. Similarly, secreted human serum albumin harboring a carboxy-terminal fusion with the chitin-binding domain derived from KlCts1p also dissociates from chitin in 20 mM NaOH, demonstrating the domain's potential utility as an affinity tag for reversible chitin immobilization or purification of alkaliphilic or alkali-tolerant recombinant fusion proteins. Finally, haploid K. lactis cells harboring a cts1 null mutation are viable but exhibit a cell separation defect, suggesting that KlCts1p is required for normal cytokinesis, probably by facilitating the degradation of septum-localized chitin.

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Mnkai, Jonathan, Manuel Ritter, Lucas Maganga, Leonard Maboko, Willyhelmina Olomi, Petra Clowes, Jessica Minich et al. "Increased HIV Incidence in Wuchereria bancrofti Microfilaria Positive Individuals in Tanzania". Pathogens 12, n.º 3 (28 de fevereiro de 2023): 387. http://dx.doi.org/10.3390/pathogens12030387.

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Background: Infections with Wuchereria bancrofti are associated with reduced immunity against concomitant infections. Indeed, our previous study described a 2.3-fold increased HIV incidence among individuals with W. bancrofti infection, as measured by the circulating filarial antigen of the adult worm. This new study aimed to retrospectively determine microfilariae status of the participants to assess if the previously described increased HIV susceptibility was associated with the presence of MF in the same cohort. Methods: CFA positive but HIV negative biobanked human blood samples (n = 350) were analyzed for W. bancrofti MF chitinase using real time PCR. Results: The PCR provided a positive signal in 12/350 (3.4%) samples. During four years of follow-up (1109 person years (PY)), 22 study participants acquired an HIV infection. In 39 PY of W. bancrofti MF chitinase positive individuals, three new HIV infections occurred (7.8 cases per 100 PY), in contrast to 19 seroconversions in 1070 PY of W. bancrofti MF chitinase negative individuals (1.8 cases per 100 PY, p = 0.014). Conclusions: In the subgroup of MF-producing Wb-infected individuals, the HIV incidence exceeded the previously described moderate increased risk for HIV seen in all Wb-infected individuals (regardless of MF status) compared with uninfected persons from the same area.

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Fadel, Firas, Yuguang Zhao, Raul Cachau, Alexandra Cousido-Siah, Francesc X. Ruiz, Karl Harlos, Eduardo Howard, Andre Mitschler e Alberto Podjarny. "New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM". Acta Crystallographica Section D Biological Crystallography 71, n.º 7 (30 de junho de 2015): 1455–70. http://dx.doi.org/10.1107/s139900471500783x.

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Chitotriosidase (CHIT1) is a human chitinase belonging to the highly conserved glycosyl hydrolase family 18 (GH18). GH18 enzymes hydrolyze chitin, anN-acetylglucosamine polymer synthesized by lower organisms for structural purposes. Recently, CHIT1 has attracted attention owing to its upregulation in immune-system disorders and as a marker of Gaucher disease. The 39 kDa catalytic domain shows a conserved cluster of three acidic residues, Glu140, Asp138 and Asp136, involved in the hydrolysis reaction. Under an excess concentration of substrate, CHIT1 and other homologues perform an additional activity, transglycosylation. To understand the catalytic mechanism of GH18 chitinases and the dual enzymatic activity, the structure and mechanism of CHIT1 were analyzed in detail. The resolution of the crystals of the catalytic domain was improved from 1.65 Å (PDB entry 1waw) to 0.95–1.10 Å for the apo and pseudo-apo forms and the complex with chitobiose, allowing the determination of the protonation states within the active site. This information was extended by hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. The results suggest a new mechanism involving changes in the conformation and protonation state of the catalytic triad, as well as a new role for Tyr27, providing new insights into the hydrolysis and transglycosylation activities.

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Kucerova, Lucie, Vaclav Broz, Badrul Arefin, Houda Ouns Maaroufi, Jana Hurychova, Hynek Strnad, Michal Zurovec e Ulrich Theopold. "The Drosophila Chitinase-Like Protein IDGF3 Is Involved in Protection against Nematodes and in Wound Healing". Journal of Innate Immunity 8, n.º 2 (23 de dezembro de 2015): 199–210. http://dx.doi.org/10.1159/000442351.

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Chitinase-like proteins (CLPs) of the 18 glycosyl hydrolase family retain structural similarity to chitinases but lack enzymatic activity. Although CLPs are upregulated in several human disorders that affect regenerative and inflammatory processes, very little is known about their normal physiological function. We show that an insect CLP (Drosophila imaginal disc growth factor 3, IDGF3) plays an immune-protective role during entomopathogenic nematode (EPN) infections. During these infections, nematodes force their entry into the host via border tissues, thus creating wounds. Whole-genome transcriptional analysis of nematode-infected wild-type and Idgf3 mutant larvae have shown that, in addition to the regulation of genes related to immunity and wound closure, IDGF3 represses Jak/STAT and Wingless signaling. Further experiments have confirmed that IDGF3 has multiple roles in innate immunity. It serves as an essential component required for the formation of hemolymph clots that seal wounds, and Idgf3 mutants display an extended developmental delay during wound healing. Altogether, our findings indicate that vertebrate and invertebrate CLP proteins function in analogous settings and have a broad impact on inflammatory reactions and infections. This opens the way to further genetic analysis of Drosophila IDGF3 and will help to elucidate the exact molecular context of CLP function.

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Makarova, S. I., D. V. Mitrofanov, A. B. Shintyapina, E. G. Komova, V. V. Zelenskaya, T. V. Kartseva, E. G. Kondyurina e V. A. Vavilin. "Search for associations between polymorphic variants of human acid chitinase gene and bronchial asthma in children of Novosibirsk". Siberian Journal of Clinical and Experimental Medicine 36, n.º 4 (3 de janeiro de 2022): 92–98. http://dx.doi.org/10.29001/2073-8552-2021-36-4-92-98.

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High prevalence of bronchial asthma among the population (about 300 million people all over the world) provides rationale for the search for candidate genes of disease. Human acidic chitinase (CHIA (AMCase)), encoded by the CHIA gene, is involved in the degradation of chitin, a component of the fungal cell wall and arthropod exoskeleton, which, if present in food or house dust, is a provoking factor for the bronchial asthma (BA) development. Functionally significant mutations in the CHIA gene may apparently increase the risk of susceptibility to BA.Aim. The aim of the study was to assess the associations of single nucleotide polymorphisms (SNPs) rs12033184 and rs3806448 in the CHIA gene with bronchial asthma in children in Novosibirsk.Material and Methods. The study was organized as case-control. A total of 537 blood samples were used. SNPs were determined by real-time PCR. The associations of polymorphic variants with the disease were assessed by the odds ratio.Results. No associations of rs12033184 and rs3806448 with BA were found.Conclusion. The role of acidic chitinase gene in the development of BA in residents of Novosibirsk was found to be less significant than in the Indian population where it was previously shown to be associated with the disease.

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Song, Si-Youn, Young Jung Seo, Yong-Woon Kim, So-Young Park, Chang Hoon Bae e Yong-Dae Kim. "Effect of Onchocerca Volvulus Chitinase on MUC5B Expression in Human Airway Epithelial Cells". American Journal of Rhinology & Allergy 27, n.º 1 (janeiro de 2013): 3–7. http://dx.doi.org/10.2500/ajra.2013.27.3830.

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Görgens, S. W., M. Hjorth, K. Eckardt, S. Wichert, F. Norheim, T. Holen, S. Lee et al. "The exercise-regulated myokine chitinase-3-like protein 1 stimulates human myocyte proliferation". Acta Physiologica 216, n.º 3 (8 de setembro de 2015): 330–45. http://dx.doi.org/10.1111/apha.12579.

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Hong, J. Y., K. E. Lee, K. W. Kim, E. S. Kim, J. Y. Park, M. H. Sohn e K. E. Kim. "Effect of Chitinase on Il-8 Gene Expression in Human Respiratory Epithelial Cells". Journal of Allergy and Clinical Immunology 119, n.º 1 (janeiro de 2007): S290. http://dx.doi.org/10.1016/j.jaci.2006.12.505.

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UJITA, Minoru, Kaori SAKAI, Keishi HAMAZAKI, Masahiko YONEDA, Shigeki ISOMURA e Akira HARA. "Carbohydrate Binding Specificity of the Recombinant Chitin-binding Domain of Human Macrophage Chitinase". Bioscience, Biotechnology, and Biochemistry 67, n.º 11 (janeiro de 2003): 2402–7. http://dx.doi.org/10.1271/bbb.67.2402.

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Kim, Young-Dae, Chang-Hoon Bae e Si-Youn Song. "Effect of Onchocerca Volvulus Chitinase on MUC5B Expression in Human Airway Epithelial Cells". Otolaryngology–Head and Neck Surgery 149, n.º 2_suppl (23 de agosto de 2013): P257. http://dx.doi.org/10.1177/0194599813496044a348.

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