Type 2 diabetes risk gene Dusp8 is a gatekeeper for hypothalamic Jnk signaling and insulin sensitivity

Recent genome-wide association studies (GWAS) identified Dusp8, a dual-specificity phosphatase targeting MAP kinases, as type 2 diabetes risk gene. Here, we unravel Dusp8 as gatekeeper in the hypothalamic control of glucose homeostasis in mice and humans. Male but not female Dusp8 loss-of-function mice, either with global or CRH neuron-specific deletion, had impaired systemic glucose tolerance and insulin sensitivity when exposed to high-fat diet (HFD). Mechanistically, we found impaired hypothalamic–pituitary–adrenal (HPA) axis feedback, blunted sympathetic responsiveness, and chronically elevated corticosterone levels driven by hypothalamic hyperactivation of Jnk signaling. Accordingly, global Jnk1 ablation, AAV-mediated Dusp8 overexpression in the mediobasal hypothalamus, or metyrapone-induced chemical adrenalectomy rescued the impaired glucose homeostasis of male Dusp8 KO mice, respectively. This sex-specific and rheostatic role of murine Dusp8 in governing hypothalamic Jnk signaling, insulin sensitivity and systemic glucose tolerance was consistent with fMRI data in human volunteers that revealed an association of the DUSP8 rs2334499 risk variant with hypothalamic insulin resistance in men. In summary, our findings suggest GWAS-identified gene Dusp8 as novel hypothalamic factor that plays a functional role in the etiology of type 2 diabetes.