Abstract
Inflammatory damage contributes to β cell failure in type 1 and 2 diabetes (T1D and T2D, respectively). Mitochondria are damaged by inflammatory signaling in β cells, resulting in impaired bioenergetics and initiation of proapoptotic machinery. Hence, the identification of protective responses to inflammation could lead to new therapeutic targets. Here, we report that mitophagy serves as a protective response to inflammatory stress in both human and rodent β cells. Utilizing in vivo mitophagy reporters, we observed that diabetogenic proinflammatory cytokines induced mitophagy in response to nitrosative/oxidative mitochondrial damage. Mitophagy-deficient β cells were sensitized to inflammatory stress, leading to the accumulation of fragmented dysfunctional mitochondria, increased β cell death, and hyperglycemia. Overexpression of CLEC16A, a T1D gene and mitophagy regulator whose expression in islets is protective against T1D, ameliorated cytokine-induced human β cell apoptosis. Thus, mitophagy promotes β cell survival and prevents diabetes by countering inflammatory injury. Targeting this pathway has the potential to prevent β cell failure in diabetes and may be beneficial in other inflammatory conditions.
Authors
Vaibhav Sidarala, Gemma L. Pearson, Vishal S. Parekh, Benjamin Thompson, Lisa Christen, Morgan A. Gingerich, Jie Zhu, Tracy Stromer, Jianhua Ren, Emma C. Reck, Biaoxin Chai, John A. Corbett, Thomas Mandrup-Poulsen, Leslie S. Satin, Scott A. Soleimanpour
Figure 7
Mitophagy deficiency reveals STZ-induced mitochondrial network defects in β cells in vivo.
