Repeated hypoglycemia in diabetic mice induce hypothalamic mitochondrial and synaptic activity deregulations characteristic of neurodegenerative diseases

Repeated exposures to insulin-induced hypoglycemia in diabetic patients progressively impair the counter-regulatory response (CRR) that restores normoglycemia. This defect is characterized by reduced secretion of glucagon and other counter-regulatory hormones. Evidence indicates that glucose responsive neurons located in the hypothalamus, orchestrate the CRR. Here, we aimed at identifying the changes in hypothalamic gene and protein expression that underlie impaired CRR. High fat diet fed and low dose streptozocin-treated C57BL6N mice were exposed to one (acute hypoglycemia, AH) or multiple (recurrent hypoglycemia, RH) insulin-induced hypoglycemic episodes. Single nuclei RNA sequencing (snRNAseq) data were obtained from the hypothalamus and cortex of AH and RH mice. Proteomic data were also obtained from hypothalamic synaptosomal fractions. The present study shows that repeated moderate hypoglycemia in diabetic mice lead, in the hypothalamus, to multiple cellular physiology changes, affecting all cell types and their interactions, which show striking features of neurodegenerative diseases. It also shows that repeated hypoglycemic episodes affect very differently the hypothalamus and the cortex.