Nephrin is expressed in the pancreatic beta cells

Aims/hypothesis. The NPHS1 gene product, nephrin, is a crucial component of the glomerular filtration barrier preventing proteinuria and previously as sumed to be kidney-specific. The aim of this study was to describe the expr ession of nephrin mRNA and protein in human pancreas as well as identify th e nephrin-expressing cell types. Methods. RNA dot blot, reverse transcriptase-polymerase chain reaction, seq uencing, immunoblotting and dual immunofluorescence were used for the chara cterisation of nephrin in the pancreas. Results. Except for the kidney, the pancreas was found to be the only tissu e expressing nephrin as screened with a human tissue RNA dot blot. The expr ession was verified with reverse transcriptase-polymerase chain reaction an d by sequencing nephrin from a human pancreatic complementary DNA library. Nephrin antibody in immunoblot detected a 165000 M-r protein in the pancrea s. Dual immunofluorescence showed that nephrin was specifically localised i n the beta cells of the islets of Langerhans. There was no overlap with glu cagon, somatostatin, or the ductal cell marker cytokeratin 19. Conclusion/interpretation. These data show that nephrin is a novel molecule of pancreatic beta cells.