Recovery of human type 2 diabetes beta cell function associates with transcriptomic signatures that point to novel therapeutic targets

Remission of type 2 diabetes (T2D) may occur after very low-calorie diets or bariatric surgery, and is associated with improved pancreatic beta cell function. Here, we evaluated if T2D beta cell dysfunction can be rescued ex-vivo and which are the molecular mechanisms involved. Islets from 19 T2D donors were studied after isolation (“basal”) and following culture at 5.5 or 11.1 mmol/l glucose (“cultured”). We evaluated glucose-stimulated insulin secretion (GSIS) and transcriptomes by RNA sequencing, correlated insulin secretion changes (“cultured” vs “basal”) to global gene expression, and searched for potential therapeutic gene targets and compounds that mimic gene signatures of recovered beta cell function in T2D islets. GSIS improved in 12 out of 19 islet preparations from T2D donors after culture at 5.5 mmol/l glucose (insulin stimulation index increased from 1.4±0.1 to 2.3±0.2, p<0.01), mainly due to greater insulin response to high glucose. No improvement was seen in islets cultured at 11.1 mmol/l glucose. Functional improvement was accompanied by changes in expression of 438 genes, many of which involved in functional and inflammatory processes. Of them, 123 were significantly correlated with changes in glucose-stimulated insulin secretion. Drug repurposing and target identification analyses for beta cell functional recovery predicted several chemical (including Src inhibitors and anti-inflammatory drugs) and genetic hits in pathways such as chemokine, MAPK, ERBB signaling, and autophagy. In conclusion, defective insulin secretion in T2D can be rescued, at least in part, by a “non-diabetic” milieu, demonstrating important T2D beta cell functional plasticity. This recovery associates with specific transcriptomic traits, pointing to known as well as novel therapeutic targets to induce T2D remission.