The
neuropeptide urocortin 3 (UCN3) has a beneficial effect on metabolic disorders, such as
obesity, diabetes, and
cardiovascular disease. It has been reported that UCN3 regulates insulin secretion and is dysregulated with increasing severity of
obesity and diabetes. However, its function in the adipose tissue is unclear. We investigated the overexpression of UCN3 in 3T3-L1 preadipocytes and differentiated adipocytes and its effects on heat shock response, ER stress, inflammatory markers, and
glucose uptake in the presence of stress-inducing concentrations of
palmitic acid (PA). UCN3 overexpression significantly downregulated
heat shock proteins (HSP60, HSP72 and HSP90) and ER stress response markers (
GRP78, PERK, ATF6, and IRE1α) and attenuated
inflammation (TNFα) and apoptosis (CHOP). Moreover, enhanced
glucose uptake was observed in both preadipocytes and mature adipocytes, which is associated with upregulated phosphorylation of AKT and ERK but reduced p-JNK. Moderate effects of UCN3 overexpression were also observed in the presence of 400 μM of PA, and macrophage
conditioned medium dramatically decreased the UCN3
mRNA levels in differentiated 3T3-L1 cells. In conclusion, the beneficial effects of UCN3 in adipocytes are reflected, at least partially, by the improvement in cellular stress response and
glucose uptake and attenuation of
inflammation and apoptosis.