Faster amylin aggregation on fibrillar collagen hastens diabetic progression through β cell death and loss of function

Abstract

Amyloid deposition of the neuroendocrine peptide amylin in islet tissues is a hallmark of type 2 diabetes (T2DM), leading to beta cell toxicity through nutrient deprivation, membrane rupture and apoptosis. Though accumulation of toxic amylin aggregates in islet matrices is well documented, the role of the islet extracellular matrix in mediating amylin aggregation and its pathological consequences remains elusive. Here, we address this question by probing amylin interaction with collagen I (Col I) whose expression in the islet tissue increases during diabetes progression. By combining multiple biophysical techniques, we show that hydrophobic, hydrophilic & cation-pi interactions regulate amylin binding to Col I, with fibrillar collagen driving faster amylin aggregation. Amylin-entangled Col I matrices containing high amounts of amylin induce death and loss of function of INS1E beta-cells. Together, our results illustrate how amylin incorporation in islet matrices through amylin-Col interactions drives T2DM progression by impacting beta-cell viability and insulin secretion.