Calsyntenin 3β Is Dynamically Regulated by Temperature in Murine Brown Adipose and Marks Human Multilocular Fat

Activation of thermogenic adipose tissue is linked to improved metabolic outcomes in mice and humans. Dissipation of energy as heat during thermogenesis relies on sufficient innervation of fat by sympathetic nerve fibers, a process recently proposed to be regulated by the adipose-specific calsyntenin3 beta (Clstn3 beta)-S100b axis. Here we aimed 1) to assess enrichment patterns ofCLSTN3 beta,S100bas well as the previously annotated neuronalCLSTN3 alpha in perirenal brown and subcutaneous white human fat specimens, and 2) to investigate if the novelClstn3 beta is dynamically regulated by changes in environmental temperatures and nutritional stress in thermogenic adipose tissues in mice. We provide evidence forCLSTN3 beta enrichment in multilocular perirenal fat located anatomically in the proximity to both the adrenal gland and sympathetic nerve bundles innervating the kidney in humans. Moreover, transcript levels ofCLSTN3 beta, but notS100borCLSTN3 alpha, positively correlate with uncoupling protein 1 (UCP1) expression in human adipose tissue. Our results further show thatClsnt3 beta is preferentially expressed in brown adipocytes and is highly responsive to changes in environmental temperature and obesity state in mice. Collectively, this brief communication highlightsCLSTN3 beta as a hallmark of thermogenic adipose depots in mice and humans.