Central inhibition of IKKβ/NF-κB signaling attenuates high-fat diet-induced obesity and glucose intolerance

Abstract

Metabolic inflammation in the central nervous system might be causative for the development of overnutritioninduced metabolic syndrome and related disorders, such as obesity, leptin and insulin resistance, and type 2 diabetes. Here we investigated whether nutritive and genetic inhibition of the central IkBkinase b (IKKβ)/nuclear factor-κB (NF-κB) pathway in diet-induced obese (DIO) and leptin-deficientmice improves these metabolic impairments. A known prominent inhibitor of IKKβ/NF-κB signaling is the dietary flavonoid butein. We initially determined that oral, intraperitoneal, and intracerebroventricular administration of this flavonoid improved glucose tolerance and hypothalamic insulin signaling. The dosedependent glucose-lowering capacity was profound regardless of whether obesity was caused by leptin deficiency or high-fat diet (HFD). To confirm the apparent central role of IKKβ/NF-κB signaling in the control of glucose and energy homeostasis, we genetically inhibited this pathway in neurons of the arcuate nucleus, one key center for control of energy homeostasis, via specific adeno- Associated virus serotype 2-mediated overexpression of IκBα, which inhibits NF-kB nuclear translocation. This treatment attenuated HFD-induced body weight gain, body fat mass accumulation, increased energy expenditure, and reduced arcuate suppressor of cytokine signaling 3 expression, indicative for enhanced leptin signaling. These results reinforce a specific role of central proinflammatory IKKβ/NF-κB signaling in the development and potential treatment of DIO-induced comorbidities.