| First Author | Aoyagi K | Year | 2016 |
| Journal | Diabetes | Volume | 65 |
| Issue | 6 | Pages | 1648-59 |
| PubMed ID | 26953164 | Mgi Jnum | J:249354 |
| Mgi Id | MGI:5922751 | Doi | 10.2337/db15-1207 |
| Citation | Aoyagi K, et al. (2016) VAMP7 Regulates Autophagy to Maintain Mitochondrial Homeostasis and to Control Insulin Secretion in Pancreatic beta-Cells. Diabetes 65(6):1648-59 |
| abstractText | VAMP7 is a SNARE protein that mediates specific membrane fusions in intracellular trafficking and was recently reported to regulate autophagosome formation. However, its function in pancreatic beta-cells is largely unknown. To elucidate the physiological role of VAMP7 in beta-cells, we generated pancreatic beta-cell-specific VAMP7 knockout (Vamp7(flox/Y);Cre) mice. VAMP7 deletion impaired glucose-stimulated ATP production and insulin secretion, though VAMP7 was not localized to insulin granules. VAMP7-deficient beta-cells showed defective autophagosome formation and reduced mitochondrial function. p62/SQSTM1, a marker protein for defective autophagy, was selectively accumulated on mitochondria in VAMP7-deficient beta-cells. These findings suggest that accumulation of dysfunctional mitochondria that are degraded by autophagy caused impairment of glucose-stimulated ATP production and insulin secretion in Vamp7(flox/Y);Cre beta-cells. Feeding a high-fat diet to Vamp7(flox/Y);Cre mice exacerbated mitochondrial dysfunction, further decreased ATP production and insulin secretion, and consequently induced glucose intolerance. Moreover, we found upregulated VAMP7 expression in wild-type mice fed a high-fat diet and in db/db mice, a model for diabetes. Thus our data indicate that VAMP7 regulates autophagy to maintain mitochondrial quality and insulin secretion in response to pathological stress in beta-cells. |
