Gene expression profiling of HUH7-ins Lack of a granulogenic function for Chromogranin A

Previously, the insulin producing liver cell line HUH7-ins has been shown to synthesize, store and secrete insulin in response to glucose via secretory granules. The current study characterized the gene expression profile of HUH7-ins with the aim to identify changes possibly involved in the formation of granules. Additionally, experiments were conducted to determine the influence of chromogranin A (CgA) on secretory granule biogenesis (SGB) in HUH7-ins. Expression of 165 genes were significantly changed in HUH7-ins, though interestingly the majority of secretory granule associated genes, such as the chromogranins were unchanged. CgA was over-expressed in glucose unresponsive HUH7-ins cells to test whether CgA played a role in SGB and would restore the regulated secretory phenotype. Over expression affected neither the storage nor regulated secretion of insulin. These data suggest that SGB may by regulated at a post-transcriptional level with no evidence to indicate that CgA regulates SGB in the cell line HUH7-ins.