Abstract
Cell-based therapies for treating insulin-dependent diabetes (IDD) can provide a more physiologic regulation of blood glucose levels in a less invasive fashion than daily insulin injections. Promising cells include non-β cells genetically engineered to secrete insulin in response to physiologic cues; responsiveness can be introduced at the transcriptional level to regulate preproinsulin (PPI) mRNA biosynthesis. However, these cells exhibit sluggish secretion dynamics, which is not appropriate for achieving euglycemia in higher animals and, eventually, humans. In this work, we have engineered the PPI mRNA so as to destabilize it through nonsense-mediated mRNA decay (NMD). When expressed under transcriptional regulation in HepG2 hepatomas, the engineered PPI mRNA level and of the insulin secretion rate declined faster upon switching off transcription, compared to the one-copy non-engineered control. Our work provides a simple and straightforward method to improve the dynamics of transcriptionally regulated insulin secretion, which can be a useful tool in developing cell-based therapies for IDD. © 2003 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.