Excess pancreatic elastase alters acinar-β cell communication by impairing the mechano-signaling and the PAR2 pathways

Type 1 (T1D) or type 2 diabetes (T2D) are caused by a deficit of functional insulin-producing β cells. Thus, the identification of β cell trophic agents could allow the development of therapeutic strategies to counteract diabetes. The discovery of SerpinB1, an elastase inhibitor that promotes human β cell growth, prompted us to hypothesize that pancreatic elastase (PE) regulates β cell viability. Here, we report that PE is up-regulated in acinar cells and in islets from T2D patients, and negatively impacts β cell viability. Using high-throughput screening assays, we identified telaprevir as a potent PE inhibitor that can increase human and rodent β cell viability in vitro and in vivo and improve glucose tolerance in insulin-resistant mice. Phospho-antibody microarrays and single-cell RNA sequencing analysis identified PAR2 and mechano-signaling pathways as potential mediators of PE. Taken together, our work highlights PE as a potential regulator of acinar-β cell crosstalk that acts to limit β cell viability, leading to T2D. [Display omitted] •CELA3B, an exocrine gene, is upregulated in acinar cells of patients with T2D•CELA3B protein deposits in islet milieu and compromises β cell homeostasis in T2D•Telaprevir, a PE inhibitor, improves viability and function of human β cells•PE affects β cell homeostasis by impairing mechano-signaling and PAR2 pathways Basile et al. observed CELA3B genes upregulated in acinar cells linked to augmented CELA3B protein within islet milieu of T2D patients, resulting in reduced β cell homeostasis secondary to impairment of two signaling hubs: mechano-signaling and PAR2 pathways. PE inhibitors rescue β cell homeostasis and point to anti-PE therapies in T2D.