Hepatocyte growth factor regulates proliferation and differentiation of epithelial monolayers derived from islets of postnatal rat pancreas

Abstract

Hepatocyte growth factor (HGF) has been suggested to be a potent regulator of -cell function and proliferation. The purpose of this study was to investigate whether HGF could regulate the proliferation and differentiation of islet-derived epithelial monolayers into insulin-producing cells. We have generated islet-derived epithelial monolayers that are enriched with cells expressing c-Kit, a tyrosine kinase receptor and putative marker, from isolated postnatal rat islets. Monolayers were cultured on type I collagen gel and treated in defined differentiation medium with or without HGF (50 ng/ml) for 7 days. Subsequently, the expression of transcription factors and pancreatic endocrine cell markers as well as c-Kit expression were compared between the HGF (HGF + ), no HGF treatment (HGF ) and monolayers without differentiation medium (control) groups, using immunocytochemical and RT-PCR approaches. We observed that the number of c-Kit-, glucose transport type 2 (Glut2)-and the transcription factor pancreatic duodenal homeobox-1 (PDX-1)-expressing cells were significantly increased in the HGF + group. The expression of insulin at the mRNA and protein level was also increased in this treatment group with a 1·7-fold increase in basal insulin release and a 2·3-fold increase in insulin content in comparison with the HGF group. A high proliferative capacity was also found in the HGF + group. Co-localization of insulin and PDX-1 or Glut2 was revealed frequently in cells treated with HGF + with occasional co-staining of c-Kit and insulin observed. This study showed that HGF can activate the proliferation and differentiation of islet-derived epithelial monolayer into insulin-producing cells. However, no formation of islet-like clusters was observed. Taken together, this study implies that HGF mediates differentiation of immature cell types into insulin-expressing cells; however, HGF supplementation alone is insufficient in restoring full -cell function.

Hepatocyte Growth Factor Regulates Migration of Olfactory Interneuron Precursors in the Rostral Migratory Stream through Met-Grb2 Coupling

“…The HGF concentration used in this assay (50 ng/ml) is known to induce cell proliferation in different cell systems (Wang et al, 2004). Thus, we wondered whether HGF could exert other functions in this system in addition to the promigratory effect.…”

Targeted Inactivation of Hepatocyte Growth Factor Receptor c-met in β-Cells Leads to Defective Insulin Secretion and GLUT-2 Downregulation Without Alteration of β-Cell Mass

“…Third, an alternative explanation is that HGF acts as a physiological suppressor of ␤-cell differentiation, and its absence permits increased generation of new ␤-cells. This seems unlikely because: 1) HGF action would be deleted only in differentiated ␤-cells because we used the RIP promoter for these studies, and it should not be deleted from ␤-cell precursors before they express insulin (45); 2) HGF overexpression in transgenic mice results in a small but significant increase in islet number (20); and 3) HGF has been shown to induce in vitro the differentiation of pancreatic acinar and islet-derived epithelial cells into insulin-expressing cells (32,46). Finally, it is possible that the decreased ␤-cell function and diminished glucose tolerance in MetCKO mice induce compensatory ␤-cell neogenesis.…”

Identification and expansion of pancreatic stem/progenitor cells

“…In vitro studies showed that HGF promotes beta cell proliferation with the support of a fibrin matrix [97]. Recent studies demonstrated that HGF mediates differentiation of immature cell types into insulin-expressing cells [98]. Together, the above data suggests that GLP-1, exendin-4, FGFs, BTC and HGF are useful to promote neogenesis of beta cells from the progenitor cells inside the islets and pancreatic ductal cells.…”