Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10721 (c-kit)
 6,575 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The limitation of available islets for transplantation is a major obstacle for the treatment of diabetes through islet therapy. However, islet monolayers expanded ex vivo may provide a source of progenitor cells and a model to help understand islet development from precursor cell types. The existence of progenitor cells within the islets is highly likely, yet, to date, no fully defined or characterized postnatal stem cell has been isolated, expanded or marked. Our study evaluates the expression of progenitor markers, including the haematopoietic stem cell marker c-Kit, in epithelial monolayers derived from postnatal rat islets through immunofluorescence and RT-PCR, and the ability of precursor-rich monolayers to reform islet-like structures. Islets formed confluent monolayers when cultured on a type I collagen gel which lacked endocrine phenotypes but were positive for cytokeratin 20 and contained an increased proportion of proliferating c-Kit-expressing cells, with the proportion reaching a maximum of 45+/-6% at 8 weeks of culture. Evaluation of transcription factors at the mRNA level revealed constant PDX-1, ngn3 and Pax4 expression, while undifferentiated cell markers, such as Oct4 and alpha-fetoprotein, were also detected frequently after 4 weeks of culture. Changing the extracellular matrix protein to laminin-rich Matrigel, the monolayers re-formed islet-like clusters that secreted insulin in a glucose-responsive fashion. Our data show that islets can be expanded ex vivo to form epithelial monolayers with rich undifferentiating cell populations that are characterized by cells expressing the progenitor markers. These monolayers are capable of extensive proliferation and retain plasticity to form new islet cells, and c-Kit-expressing cells may play an important role in new islet cluster formation.
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PMID:Phenotypic analysis of c-Kit expression in epithelial monolayers derived from postnatal rat pancreatic islets. 1522 36

Stem cell factor (SCF), a progenitor cell growth factor, binds to and activates the c-Kit receptor tyrosine kinase, which is critical for early stem cell differentiation in haematopoiesis and gametogenesis. Nothing is known regarding these interactions during islet development in the human fetal pancreas. The present study was to investigate whether an increase in c-Kit receptor activity in isolated human fetal islet-epithelial clusters, by giving exogenous SCF, would promote beta-cell development. In the intact fetal pancreas, SCF and c-Kit were observed co-localizing with cytokeratin 19 in both ductal and newly forming islet cells. Islet cells isolated from 14 to 16 weeks fetal pancreata were cultured with SCF (50 ng/ml) or vehicle for 48 h. We observed an increase in the number of c-Kit-, pancreatic and duodenal homeobox gene 1- (PDX-1-), insulin- and glucagon-expressing cells in the SCF-treated group (PDX-1 and insulin, p < 0.05). PDX-1 and c-Kit mRNA levels were also up-regulated in the SCF group (PDX-1, p < 0.05), with no change in preproinsulin or proglucagon gene expression. Co-localization of insulin with PDX-1 or c-Kit was observed frequently in SCF-treated cultures. A significantly (p < 0.05) greater proliferative capacity of islet-epithelial clusters was found in the SCF group in parallel with increased (p < 0.02) phosphorylation of Akt in a phosphatidylinositol-3 kinase (PI3K)-dependent manner. Our results demonstrate that SCF/c-Kit interactions are likely to be involved in mediating islet cell differentiation and proliferation during human fetal pancreatic development, and that phosphorylated Akt may have a role downstream of SCF/c-Kit signaling.
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PMID:Stem cell factor/c-Kit interactions regulate human islet-epithelial cluster proliferation and differentiation. 1621 78

An understanding of beta cell regeneration is needed if we are to develop new treatment modalities in diabetes mellitus. Lineage tracing studies have shown that all pancreatic cell types, including beta cells, arise from PDX-1-expressing precursor cells. We studied beta cell regeneration by analyzing the immunocytochemical expression of the transcription factors, PDX-1, PBX-1, and MEIS2, and that of the potential precursor cell markers, c-Kit and nestin, using the model of streptozotocin (STZ)-induced diabetes in rats. The pancreata were examined 3, 7, and 14 days after STZ administration. PDX-1 expression, but not that of MEIS2 and PBX-1, transiently increased on day 7. c-Kit expression was found to be upregulated in islet cells at all points in time, while nestin expression was lacking. Ki-67 labeling was increased in islets on days 3 and 7. These results suggest that temporary upregulation of PDX-1 and prolonged overexpression of c-Kit may play a role during beta cell regeneration.
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PMID:Expression of transcription factors and precursor cell markers during regeneration of beta cells in pancreata of rats treated with streptozotocin. 1723 68

The receptor, c-Kit, and its ligand, stem cell factor (SCF), are critical for hematopoietic stem cell differentiation and have been implicated in the development, function, and survival of rodent islets. Previously, we reported that exogenous SCF treatments of cultured human fetal (14-16 wk fetal age) islet-epithelial clusters enhanced islet cell differentiation and proliferation (Li J, Goodyer CG, Fellows F, Wang R. Int J Biochem Cell Biol 38: 961-972, 2006). In the present study, we examined the expression pattern of c-Kit in early to midgestation human fetal pancreata and the relevance of c-Kit receptor tyrosine kinase for insulin gene expression and beta-cell survival. c-Kit is expressed in the intact pancreas in a cell-specific manner, with a significant decrease in immunoreactivity in the duct regions from 8 to 21 wk fetal age, paralleled by a significant increase in expression within endocrine regions. These c-Kit-positive cells are highly proliferative and show frequent coexpression with insulin and glucagon. Treatment of islet-epithelial clusters with anti-ACK45 antibody stimulates c-Kit phosphorylation paralleled by a significant increase in PDX-1 and insulin expression, increased cell proliferation, and reduced beta-cell death. In contrast, transient transfection with c-Kit siRNA results in a three- to fourfold decrease in c-Kit, PDX-1, and insulin expression and decreased cell proliferation. This study describes important changes in the distribution and dynamics of c-Kit-expressing cells during human fetal pancreatic neogenesis, suggesting that c-Kit may be a marker for human pancreatic islet progenitor cells. Functional analysis of the c-Kit receptor tyrosine kinase provides evidence that phosphorylation of c-Kit receptor may be involved in mediating early beta-cell differentiation and survival.
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PMID:Expression of c-Kit receptor tyrosine kinase and effect on beta-cell development in the human fetal pancreas. 1751 80

Tumor cells have the capability to trans- and to dedifferentiate, for example by reactivating embryonic development genes and stem cell characteristics. The aim of our study was to show the differential expression of stem- and progenitor cell markers in human hepatocellular carcinoma cell lines (HCC). Different human HCC cell lines (HUH7, HUH7 5-15, HUH7 pcDNA3.1, Hep3B and HepG2) were cultured under standard conditions in vitro or implanted subcutaneously (5x10(6) cells) in male NMRI mice. Specimens were characterized by quantitative real-time PCR, Western blotting, methylation-specific PCR and immunohistochemistry for markers of differentiation (cytokeratins, vimentin), embryonic development or stem cells (PTC, PDX-1, SHH, Thy1, c-kit, CD34, beta-catenin, Ki-67). The investigated HCC cell lines showed different patterns of marker expression allowing to distinguish four distinct groups: the classical cholangiocellular type (Huh-7, Huh-7 pcDNA3.1, Hep3B) with expression of CK7/19, beta-catenin and CD34; a dedifferentiated mesenchymal-proliferative type (Huh-7 5-15) characterized by CK19, Vimentin and Ki-67; a dedifferentiated embryonic-development type (Hep3B implanted in matrigel) with expression of CK19, beta-catenin and PTC and a classical HCC type (HepG2) showing CK18/19 and beta-catenin expression. HCC cell lines showed significantly different expression patterns of differentiation markers in a xenograft model. Furthermore, direct association of some markers was observed. The groups differ from each other in expression patterns, but also show that environmental factors play an important role in the behaviour of cells.
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PMID:Cellular plasticity of trans- and dedifferentiation markers in human hepatoma cells in vitro and in vivo. 1951 53

Recent evidence has shown that stem cell factor (SCF) and its receptor, c-Kit, have an important role in pancreatic islet development by promoting islet cell differentiation and proliferation. In this study, we examined the role of c-Kit and SCF in the differentiation and proliferation of insulin- and glucagon-producing cells using a human pancreatic duct cell line (PANC-1). Our study showed that increased expression of endocrine cell markers (such as insulin and glucagon) and transcription factors (such as PDX-1 and PAX-6) coincided with a decrease in CK19(+) and c-Kit(+) cells (P<0.001) during PANC-1 cell differentiation, determined by immunofluorescence and qRT-PCR. Cells cultured with exogenous SCF showed an increase in insulin(+) (26%) and glucagon(+) (35%) cell differentiation (P<0.01), an increase in cell proliferation (P<0.05) and a decrease in cell apoptosis (P<0.01). siRNA knockdown of c-Kit resulted in a decrease in endocrine cell differentiation with a reduction in PDX-1 and insulin mRNA, as well as the number of cells immunostaining for PDX-1 and insulin. Taken together, these results show that c-Kit/SCF interactions are involved in mediating islet-like cluster formation and islet-like cell differentiation in a human pancreatic duct cell line.
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PMID:c-Kit and stem cell factor regulate PANC-1 cell differentiation into insulin- and glucagon-producing cells. 2053 Dec 94

We have recently reported that small-sized bone marrow cells (BMCs) isolated by counterflow centrifugal elutriation and depleted of lineage markers (Fr25lin(-)) have the capacity to differentiate and contribute to regeneration of injured islets. In this study, we assess some of the characteristics of these cells compared to elutriated hematopoietic progenitors (R/O) and whole BMCs in a murine model of streptozotocin-induced chemical diabetes. The GFP(bright)CD45(+) progeny of whole BMCs and R/O progenitors progressively infiltrate the pancreas with evolution of donor chimerism; are found at islet perimeter, vascular, and ductal walls; and have a modest impact on islet recovery from injury. In contrast, Fr25lin(-) cells incorporate in the islets, convert to GFP(dim)CD45(-)PDX-1(+) phenotypes, produce proinsulin, and secrete insulin with significant contribution to stabilization of glucose homeostasis. The elutriated Fr25lin(-) cells express low levels of CD45 and are negative for SCA-1 and c-kit, as removal of cells expressing these markers did not impair conversion to produce insulin. BMCs mediate two synergistic mechanisms that contribute to islet recovery from injury: support of islet remodeling by hematopoietic cells and neogenesis of insulin-producing cells from stem cells.
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PMID:Two distinct mechanisms mediate the involvement of bone marrow cells in islet remodeling: neogenesis of insulin-producing cells and support of islet recovery. 2438 Apr

Course administration streptozotocin to male C57Bl/6 mice induces a complex of symptoms typical of type 1 diabetes mellitus: hyperglycemia and insulin deficiency, focal inflammatory infiltration of the pancreas, destructive changes in the Langerhans islets, damage to the insular apparatus (reduced number of PDX1+ cells and insulin expression by the secreting cells). Male reproductive disorder are serious complications of type 1 diabetes mellitus. In "diabetic" mice, interstitial edema with inflammatory infiltration and microvascular disorders in the testicular tissue are observed, the number of endothelial precursors (CD45-/CD31+) and the total number and percentage of motile spermatozoa decreased, immature spermatogenic epithelium cells are desquamated of into the lumen of the tubules. Disturbances in the proliferation and differentiation of various spermatogonial stem cell populations (c-kit-/CD90+, c-kit+/CD90+, and CD51-/CD24+/CD52+) in diabetes can be explained by the inhibitory influence of inflammatory factors on testosterone-producing Leydig cells.
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PMID:Role of Sertoli and Leydig Cells in the Regulation of Spermatogonial Stem Cell and Development of Reproductive Disorders in Male C57Bl/6 Mice with Type 1 Diabetes Mellitus. 2918 61