The discovery of SerpinB1 as an inducer of human β-cell proliferation pointed to acinar cell-derived proteases such as pancreatic elastase (PE) being involved in regulating β-cell viability. Indeed, we observed that expression of a major form of PE, namely CELA3B, was increased in acinar cells from donors with type 2 diabetes (T2D) compared to samples from non-diabetic (ND) donors. Surprisingly, CELA3B protein levels were higher in T2D vs. ND islets, although its gene expression levels were virtually undetectable. We confirmed that increasing doses of exogenous PE is able to decrease viability of EndoC-βH3 (βH3) cells in vitro. To evaluate the effects of PE inhibition on β-cell survival, we used telaprevir, an FDA-approved drug, that we identified as a potent PE blocker using a High-Throughput Screening assays with an IC50 of 15.6 nM to inhibit PE activity. Consistent with the mitogenic effects of SerpinB1 on β-cells, telaprevir also increased human β-cell viability in in vitro and in vivo systems. By performing phospho-antibody microarrays and single-cell RNA-Seq in human islets treated with vehicle or telaprevir, we identified the mechano-signaling pathway, which integrates the signals generated by the extracellular matrix (ECM) , as a candidate pathway linking PE inhibition to β-cell viability. We validated the results by treating EndoC-βH1 (βH1) cells lacking focal adhesion kinase (siFAK) with PE +/- telaprevir. We observed that PE impaired the mechano-signaling cascade, and these effects were reversed by telaprevir in control cells, but not in siFAK cells. Furthermore, using the novel approach of Brillouin microscopy we observed that PE increased the intracellular stiffness in βH1 cells, as a readout of cytoskeleton arrangements, whereas telaprevir blunted these effects. These data point to novel pathways underlying the acinar-β-cell crosstalk that could be harnessed for therapeutic approaches to resolve diabetes in patients.
G. Basile: None. B. Wagner: Research Support; Japan Tobacco Inc., Novo Nordisk Foundation, Ono Pharmaceutical Co., Ltd., Stock/Shareholder; Moderna, Inc., Pfizer Inc. R. Kulkarni: Advisory Panel; Biomea, Novo Nordisk, REDD Pharma, Consultant; Relay Therapeutics, Research Support; Inversago, SerPlus. A. Vetere: None. J. Hu: None. O. Ijaduola: None. D. F. De jesus: n/a. K. Fukuda: None. A. M. Eltony: None. A. Yun: None. A. Choudhary: None.
JDRF: 3-PDF-2020-935-A-NNIH: U01 DK123717NIH: UC4 DK116255