Pro-Survival Role of Gelsolin in Mouse β-Cells

Abstract

We have previously shown that the Ca²⁺-dependent actin-severing protein gelsolin plays an important role in regulated insulin secretion. The aim of this study was to determine the role of gelsolin in β-cell survival as it has been shown to play a dual role in apoptosis in other cell types. MIN6 subclones B1 and C3, shown previously to express gelsolin at different levels (B1≫C3 cells), were used for this purpose. We demonstrate that B1 cells have lower levels of apoptosis and active caspase-3 when compared with C3 cells, in both standard (25 mmol/l glucose and 15% FCS) and deprived (5 mmol/l glucose and 1% FCS) conditions. Overexpression of gelsolin resulted in a decrease in the percentage of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)⁺ and active caspase-3⁺ cells. Conversely, knockdown of gelsolin by RNA interference in B1 cells caused an increase in the number of TUNEL⁺ and active caspase-3⁺ cells. Finally, the anti-apoptotic role of gelsolin was confirmed in purified primary mouse β-cells where overexpression of gelsolin resulted in a decrease in the percentage of TUNEL⁺ cells. In summary, our results show for the first time that gelsolin plays a pro-survival role in pancreatic β-cells.