| First Author | Mukherjee N | Year | 2024 |
| Journal | Mol Metab | Volume | 80 |
| Pages | 101877 | PubMed ID | 38218538 |
| Mgi Jnum | J:345944 | Mgi Id | MGI:7581440 |
| Doi | 10.1016/j.molmet.2024.101877 | Citation | Mukherjee N, et al. (2024) RIPK3 promotes islet amyloid-induced beta-cell loss and glucose intolerance in a humanized mouse model of type 2 diabetes. Mol Metab 80:101877 |
| abstractText | OBJECTIVE: Aggregation of human islet amyloid polypeptide (hIAPP), a beta-cell secretory product, leads to islet amyloid deposition, islet inflammation and beta-cell loss in type 2 diabetes (T2D), but the mechanisms that underlie this process are incompletely understood. Receptor interacting protein kinase 3 (RIPK3) is a pro-death signaling molecule that has recently been implicated in amyloid-associated brain pathology and beta-cell cytotoxicity. Here, we evaluated the role of RIPK3 in amyloid-induced beta-cell loss using a humanized mouse model of T2D that expresses hIAPP and is prone to islet amyloid formation. METHODS: We quantified amyloid deposition, cell death and caspase 3/7 activity in islets isolated from WT, Ripk3(-/-), hIAPP and hIAPP; Ripk3(-/-) mice in real time, and evaluated hIAPP-stimulated inflammation in WT and Ripk3(-/-) bone marrow derived macrophages (BMDMs) in vitro. We also characterized the role of RIPK3 in glucose stimulated insulin secretion (GSIS) in vitro and in vivo. Finally, we examined the role of RIPK3 in high fat diet (HFD)-induced islet amyloid deposition, beta-cell loss and glucose homeostasis in vivo. RESULTS: We found that amyloid-prone hIAPP mouse islets exhibited increased cell death and caspase 3/7 activity compared to amyloid-free WT islets in vitro, and this was associated with increased RIPK3 expression. hIAPP; Ripk3(-/-) islets were protected from amyloid-induced cell death compared to hIAPP islets in vitro, although amyloid deposition and caspase 3/7 activity were not different between genotypes. We observed that macrophages are a source of Ripk3 expression in isolated islets, and that Ripk3(-/-) BMDMs were protected from hIAPP-stimulated inflammatory gene expression (Tnf, Il1b, Nos2). Following 52 weeks of HFD feeding, islet amyloid-prone hIAPP mice exhibited impaired glucose tolerance and decreased beta-cell area compared to WT mice in vivo, whereas hIAPP; Ripk3(-/-) mice were protected from these impairments. CONCLUSIONS: In conclusion, loss of RIPK3 protects from amyloid-induced inflammation and islet cell death in vitro and amyloid-induced beta-cell loss and glucose intolerance in vivo. We propose that therapies targeting RIPK3 may reduce islet inflammation and beta-cell loss and improve glucose homeostasis in the pathogenesis of T2D. |
