Role of SOCS3 in POMC neurons in metabolic and cardiovascular regulation

Suppressor of cytokine signaling 3 (SOCS3) is a negative regulator of leptin signaling. We previously showed that the chronic effects of leptin on blood pressure (BP) and glucose regulation are mediated by stimulation of proopiomelanocortin (POMC) neurons. In this study we examined the importance of endogenous SOCS3 in POMC neurons in control of metabolic and cardiovascular function and potential sex differences. Male and female SOCS3(flox/flox)/POMC-Cre mice in which SOCS3 was selectively deleted in POMC neurons and control SOCS3(flox/flox) mice were studied during a control diet (CD) or a high-fat diet (HFD) and during chronic leptin infusion. Body weight was lower in male and female SOCS3(flox/flox)/POMC-Cre than control mice fed the CD, despite similar food intake. Male SOCS3(flox/flox)/POMC-Cre mice exhibited increased energy expenditure. BP and heart rate were similar in male and female SOCS3(flox/flox)/POMC-Cre and control mice fed the CD. HFD-fed male and female SOCS3(flox/flox)/POMC-Cre mice showed attenuated weight gain. HFD-induced elevations in baseline BP and BP responses to an air-jet stress test were greater in female SOCS3(flox/flox)/POMC-Cre than control mice. Chronic leptin infusion produced similar responses for food intake, body weight, oxygen consumption, blood glucose, BP, and heart rate in all groups. Thus SOCS3 deficiency in POMC neurons influences body weight regulation in the setting of CD and HFD and differentially affects BP and energy balance in a sexspecific manner but does not amplify the dietary, glycemic, or cardiovascular effects of leptin.