The Expression And Function Of Mesothelin During Rat Islet Architecture Formation And Remodeling

We expect to use high-density microarray(Affymetrix)to analyze the expression profiles of pancreas development.We generated transcriptional profiles of pancreatic tissue isolated from five biologically significant stages of development:embryonic day(E)12.5,E15.5,E18.5, newborn and adult.These analyses implicated that many genes that have been reported to be implicated in endocrine cytodifferentiation during early pancreas development,such as Pdx1,Ngn3,Pax4 and so on,were significantly elevated between E15.5 and E18.5,consistent with previous reports.Genes involved in islet functions were enriched in E18.5,which is consistent with that later gestation was very important in functional maturation of islets.Many adhesion molecules were enriched in the later gestation when islet cells migration,adhesion and islet architecture are gradually forming.Some of which have been reported to be involved in islets architecture formation and others have not,such as Mesothelin. This study was designed to investigate the expression and function of Mesothelin in development of rat pancreas.The mRNA expression levels of Mesothelin at different developmental stages were examined by RT-PCR.The expression levels of Mesothelin were detectable in E15.5 pancreas,followed by increased levels from E18.5 to P14.The expression levels reached the peak in P14 pancreas,and then decreased until adult rat pancreas.The abundance of Mesothelin protein in the rat pancreas during development were studied using western blot.Mesothelin protein expression tendency was consistent with the Mesothelin mRNA expression.Immunolocalization indicated that Mesothelin not only colocalized with insulin in islet beta-cells but also colocalized with vimentin in mesenchyme of developing rat pancreas.At last,the expression of Wnt-5a,upstream regulator of Mesothelin,was verified by real-time PCR,and showed that its expression tendency was opposite to Mesothelin.The results of our experiments show that the expression of Mesothelin concomitants with islets architecture formation and remodeling and that the Mesothelin is localized in islet cells.This suggested that Mesothelin might play a role in islet cells migration and adhesion during the process of islet architecture formation at the later gestation and in islet architecture remodeling and maturation after birth. The function of Mesothelin might be regulated by Wnt-5a.Mesenchymal cells expressing Mesothelin simultaneously might be a potential source for endocrine cells.