Asprosin is a recently discovered fasting-induced hormone that promotes hepatic glucose production. Here, we demonstrate that plasma asprosin crosses the blood-brain-barrier and directly activates orexigenic AgRP+ neurons via a cAMP-dependent pathway. This signaling results in inhibition of downstream anorexigenic POMC+ neurons in a GABA-dependent manner, resulting in appetite stimulation and a drive to accumulate adiposity and body weight. Genetic deficiency of asprosin in humans results in a syndrome characterized by low appetite and extreme leanness, which is phenocopied by mice carrying similar mutations, and one that can be fully rescued by asprosin expression. Further, we found that obese humans and mice display pathologically elevated circulating asprosin concentrations, and neutralization of plasma asprosin using a monoclonal antibody reduces appetite and body weight in obese mice, in addition to improving their glycemic profile. Thus, asprosin, in addition to performing a glucogenic function, is a centrally-acting orexigenic hormone, and one that represents a potential therapeutic target to treat both obesity and diabetes.

Differential Scanning Fluorimetry Guided Refolding (DGR) is a simple methodology that can be used to rapidly screen for and identify conditions capable of accurately refolding protein preparations, such as those obtained from Escherichia coli inclusion bodies. It allows for the production in E. coli of functional proteins that would otherwise require far more expensive production methods. This unit describes how to set up a DGR refolding assay, perform DGR refolding trials in microplate format, use MeltTraceur Web software to interactively analyze the resulting data, scale‐up protein production via refolding, and lastly, validate that the protein is properly folded. © 2018 by John Wiley & Sons, Inc.

Induction of beige adipocytes, or brown-like adipocytes, in white adipose tissues (WAT) has become an alluring possibility to combat diabetes and metabolic diseases. Beige adipocytes express abundant UCP1 protein and exert energy dissipating and thermogenic functions similar to brown adipocytes. In this study, we compared the beiging effects of a synthetic thyroid hormone receptor (TR) agonist, GC1, with the beta-adrenergic receptor (β-AR) agonist CL316243, which is generally accepted as the most efficacious beiging agent, and explored mechanistic similarities and distinctions between the two compounds in a variety of in vitro cell models. Here we show that GC1 induces beiging, in cultured adipocytes derived from inguinal WAT, to a much greater extent than CL316243; in addition, TR activation by GC1 is sufficient to induce beiging in a variety of viscerally derived white adipocytes, as well as 3T3-L1 cells, actions which CL316243 is incapable of. Both GC1 and CL316243 increased expression of ATGL and p-HSL, two key lipases known to be necessary for the activation of UCP1-mediated uncoupling and thermogenesis, although GC1 increased these proteins to a higher extent. Enzymes involved in lipid beta-oxidation, such as ACC/p-ACC and LCAD, are also much more markedly enhanced in GC1-treated cells than those treated with CL316243. Interestingly, the loss of all β-ARs, does not affect the ability of TR activation to elicit beiging, demonstrating that TR agonism induces beiging by novel mechanisms that are independent of beta-adrenergic signaling. Thus, select TR agonists appear to be sufficient to elicit beiging in a fashion that appears to be mechanistically distinct from perhaps all other known beiging agents (nearly all of which require β-AR signaling), making them important tools in assessing the therapeutic potential of beige fat activation to treat diabetes and metabolic disease. Disclosure Y. Xia: None. X. Liang: None. M.E. Lee: None. K. Phillips: None.