Chop/Ddit3 depletion in β-cells alleviates ER stress and corrects hepatic steatosis

TitleChop/Ddit3 depletion in β-cells alleviates ER stress and corrects hepatic steatosis
Publication TypeJournal Article
Year of Publication2021
AuthorsYong J, Parekh VS, Reilly SM, Nayak J, Chen Z, Lebeaupin C, Jang I, Zhang J, Prakash TP, Sun H, Murray S, Guo S, Ayala JE, Satin LS, Saltiel AR, Kaufman RJ
JournalScience Translational Medicine
Abstract

Type 2 diabetes (T2D) is a metabolic disorder characterized by hyperglycemia, hyperinsulinemia, and insulin resistance (IR). During the early phase of T2D, insulin synthesis and secretion by pancreatic β cells is enhanced, which can lead to proinsulin misfolding that aggravates endoplasmic reticulum (ER) protein homeostasis in β cells. Moreover, increased circulating insulin may contribute to fatty liver disease. Medical interventions aimed at alleviating ER stress in β cells while maintaining optimal insulin secretion are therefore an attractive therapeutic strategy for T2D. Previously, we demonstrated that germline Chop gene deletion preserved β cells in high-fat diet (HFD)-fed mice and in leptin receptor-deficient db/db mice. In the current study, we further investigated whether targeting Chop/Ddit3 specifically in murine β cells conferred therapeutic benefits. First, we showed that Chop deletion in β cells alleviated β cell ER stress and delayed glucose-stimulated insulin secretion (GSIS) in HFD-fed mice. Second, β cell-specific Chop deletion prevented liver steatosis and hepatomegaly in aged HFD-fed mice without affecting basal glucose homeostasis. Third, we provide mechanistic evidence that Chop depletion reduces ER Ca2+ buffering capacity and modulates glucose-induced islet Ca2+ oscillations, leading to transcriptional changes of ER chaperone profile ("ER remodeling"). Last, we demonstrated that a GLP1-conjugated Chop antisense oligonucleotide strategy recapitulated the reduction in liver triglycerides and pancreatic insulin content. In summary, our results demonstrate that Chop depletion in β cells provides a therapeutic strategy to alleviate dysregulated insulin secretion and consequent fatty liver disease in T2D.

URLhttps://www.science.org/doi/10.1126/scitranslmed.aba9796?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed