Project description:TAR DNA-binding protein 43 kDa (TDP-43), encoded by TARDBP, is an RNA-binding protein, the nuclear depletion of which is the histopathological hallmark of amyotrophic lateral sclerosis (ALS). Here, we show that ALS subjects have reduced early-phase insulin secretion and that the nuclear localization of TDP-43 is lost in the islets of autopsied ALS pancreas. Loss of TDP-43 inhibits exocytosis, thereby reducing early-phase insulin secretion in a cultured β cell line (MIN6). Using microarray analysis, we identified the genes causing insulin impaired in TDP knocked down MIN6 cells.
Project description:The basic helix-loop-helix (bHLH) transcription factor hairy and enhancer of split (Hes3) is a member of the Hes/Hey gene family that regulates developmental processes in progenitor cells from various tissues. We demonstrated the Hes3 expression in mouse pancreatic tissue, suggesting it may have a role in modulating beta-cell function. We employed a transfection approach to address specific functions of Hes3. Hes3 RNA interference opposed the growth of the mouse insulinoma cell line Min6. Western blotting and PCR approaches specifically showed that Hes3 RNA interference opposes the expression of Pdx1 and insulin. Likewise, Hes3 knock down reduced evoked insulin release from Min6 cells. We used microarray analysis to examine differences in gene expression when Hes3 expression was knocked down in cells grown under different culture condtions.