CTRP14 inactivation alters physical activity and food intake response to fasting and refeeding.

Secreted proteins of the C1q/TNF-related protein (CTRP) family play diverse functions in different organ systems. In the brain, CTRP14/C1QL1 is required for the proper establishment and maintenance of synapses between climbing fibers and cerebellar Purkinje cells. Beyond the central nervous system, the function of CTRP14 is largely unknown. A recent genome-wide association study has implicated CTRP14/C1QL1 as a candidate gene associated with total body fat mass. Here, we explored the potential metabolic roles of CTRP14. We show that Ctrp14 expression in peripheral tissues is dynamically regulated by fasting-refeeding and high-fat feeding. In the chow-fed basal state, Ctrp14 deletion modestly reduces glucose tolerance in knockout (KO) male mice and affects physical activity in a sex- and nutritional state-dependent manner. In the ad libitum fed state, Ctrp14 KO male mice have lower physical activity. In contrast, female KO mice have increased physical activity in the fasted and refed states. In response to an obesogenic diet, CTRP14-deficient mice of either sex gained similar weight and are indistinguishable from wild-type littermates in body composition, lipid profiles, and insulin sensitivity. Ambulatory activity, however, is reduced in Ctrp14 KO male mice. Food intake is also reduced in Ctrp14 KO male mice in the refed period following food deprivation. Meal pattern analyses indicate that decreased caloric intake from fasting to refeeding is due, in part, to smaller meal size. We conclude that CTRP14 is largely dispensable for metabolic homeostasis, but highlight context-dependent and sexually dimorphic metabolic responses of Ctrp14 deletion affecting physical activity and ingestive behaviors. NEW & NOTEWORTHY CTRP14 is a secreted protein whose function in the peripheral tissues is largely unknown. We show that the expression of Ctrp14 in peripheral tissues is regulated by metabolic and nutritional state. We generated mice lacking CTRP14 and show that CTRP14 deficiency alters physical activity and food intake in response to fasting and refeeding. Our data has provided new and valuable information on the physiological function of CTRP14.