Lowering an ER stress-regulated long noncoding RNA protects mice from diabetes and isolated pancreatic islets from cell death

We investigated the role of the endoplasmic reticulum (ER) stress-regulated long noncoding RNA (lncRNA) lncMGC in pancreatic islets and the pathology of type 1 diabetes (T1D), as well as the potential of lncMGC-based therapeutics. In vivo, blood glucose levels (BGLs) and HbA1c were significantly lower in lncMGC-knockout (KO)-streptozotocin (STZ)-treated diabetic mice compared to wild-type STZ. Antisense oligonucleotides (GapmeR) targeting lncMGC significantly attenuated insulitis and BGLs in T1D NOD mice compared to GapmeR-negative control (NC). GapmeR-injected T1D Akita mice showed significantly lower BGLs compared to Akita-NC mice. hlncMGC-GapmeR lowered BGLs in partially humanized lncMGC (hlncMGC)-STZ mice compared to NC-injected mice. CHOP (ER stress regulating transcription factor) and lncMGC were upregulated in islets from diabetic mice but not in lncMGC-KO and GapmeR-injected diabetic mice, suggesting ER stress involvement. In vitro, hlncMGC-GapmeR increased the viability of isolated islets from human donors and hlncMGC mice and protected them from cytokine-induced apoptosis. Anti-ER stress and anti-apoptotic genes were upregulated, but pro-apoptotic genes were down-regulated in lncMGC KO mice islets and GapmeR-treated human islets. Taken together, these results show that a GapmeR-targeting lncMGC is effective in ameliorating diabetes in mice and also preserves human and mouse islet viability, implicating clinical translation potential.