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Query: UNIPROT:P10721 (c-kit)
 6,575 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oval cells that develop in the rat 2-acetylaminofluorene/partial hepatectomy (AAF/PH) model express the c-kit receptor tyrosine kinase (KIT) and its ligand, stem cell factor (SCF). We investigated the role of the SCF/KIT system in the development of oval cells using Ws/Ws rats, whose c-kit kinase activity was severely impaired owing to a small deletion in the kinase domain. On days 7, 9, and 13 after PH in the AAF/PH model, the development of oval cells was remarkably suppressed in Ws/Ws rats when compared with that of the control normal (+/+) rats. However, oval cells that developed in Ws/Ws rats expressed marker proteins of oval cells, such as alpha-fetoprotein (AFP), cytokeratin-19 (CK-19), and flt-3 receptor tyrosine kinase, similar to those of +/+ rats. Furthermore, labeling with [3H]-thymidine and immunostaining of Ki-67 showed that the proliferative activity of oval cells that developed in Ws/Ws rats was comparable with that of +/+ rats. The present results indicate that the signal transduction of the SCF/KIT system plays a crucial role in the development of oval cells, at least, in the rat AAF/PH model, and suggest that KIT-mediated signal transduction plays only a small role in determining the phenotype and in the proliferative activity of oval cells.
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PMID:Role of c-kit receptor tyrosine kinase in development of oval cells in the rat 2-acetylaminofluorene/partial hepatectomy model. 1005 67

Proliferation and differentiation of hepatic stem cell progenies (i.e., oval cells) sustain liver regeneration when the replicative and functional capacity of hepatocytes is impaired. The signaling pathways that control stem cell activation remain poorly understood. In this study, we investigated the involvement of nuclear factor-kappa B (NF-kappaB) and signal transducer and activator of transcription 3 (STAT3) in oval cell-mediated liver regeneration induced by 2-acetylaminofluorene/partial hepatectomy (AAF/PH) protocol. Using OV1 as a marker for identification and sorting of oval cells, we established that both NF-kappaB and STAT3 were highly activated in the OV1(+) cell population. Three distinct subpopulations of oval cells were defined as OV1(low), OV1(medium), and OV1(high), based on the intensity of OV1 staining. Quantitative polymerase chain reaction analysis revealed that they represent different stages of oval cell differentiation along hepatocyte lineage. OV1(low) cells displayed the least differentiated phenotype as judged by high expression of c-kit and lack of hepatocytic differentiation markers, whereas OV1(high) cells lost c-kit expression, were more proliferative, and acquired more mature hepatocytic phenotype. Notably, NF-kappaB was activated uniformly in all three subpopulations of oval cells. In contrast, phosphorylation of STAT3 was detected only in OV1(high) cells. In conclusion, transcriptional activity supported by NF-kappaB and STAT3 is required for oval cell activation, expansion, and differentiation. The differential induction of NF-kappaB and STAT3 point to a distinct role for these transcription factors at different stages of hepatic stem cell differentiation.
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PMID:Activation of NF-kappaB and STAT3 in rat oval cells during 2-acetylaminofluorene/partial hepatectomy-induced liver regeneration. 1476 90

Despite extensive studies, the hematopoietic versus hepatic origin of liver progenitor oval cells remains controversial. The aim of this study was to determine the origin of such cells after liver injury and to establish an oval cell line. Rat liver injury was induced by subcutaneous insertion of 2-AAF pellets for 7 days with subsequent injection of CCl(4). Livers were removed 9 to 13 days post-CCl(4) treatment. Immunohistochemistry was performed using anti-c-kit, OV6, Thy1, CK19, AFP, vWF and Rab3b. Isolated non-parenchymal cells were grown on mouse embryonic fibroblast, and their gene expression profile was characterized by RT-PCR. We identified a subpopulation of OV6/CK19/Rab3b-expressing cells that was activated in the periportal region of traumatized livers. We also characterized a second subpopulation that expressed the HSCs marker c-kit but not Thy1. Although we successfully isolated both cell types, OV6/CK19/Rab3b(+) cells fail to propagate while c-kit(+)-HSCs appeared to proliferate for up to 7 weeks. Cells formed clusters which expressed c-kit, Thy1 and albumin. Our results indicate that a bona fide oval progenitor cell population resides within the liver and is distinct from c-kit(+)-HSCs. Oval cells require the hepatic niche to proliferate, while cells mobilized from the circulation proliferate and transdifferentiate into hepatocytes without evidence of cell fusion.
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PMID:Characterization of two distinct liver progenitor cell subpopulations of hematopoietic and hepatic origins. 1678 9