Myonectin (CTRP15), a Novel Myokine That Links Skeletal Muscle to Systemic Lipid Homeostasis *

摘要: Skeletal muscle plays important roles in whole-body glucose and fatty acid metabolism. However, also secretes cytokines growth factors (collectively termed myokines) that can potentially act an autocrine, a paracrine, and/or endocrine manner to modulate metabolic, inflammatory, other processes. Here, we report the identification characterization of myonectin, novel myokine belonging C1q/TNF-related protein (CTRP) family. Myonectin transcript was highly induced differentiated myotubes predominantly expressed by skeletal muscle. Circulating levels myonectin were tightly regulated metabolic state; fasting suppressed, but refeeding dramatically increased, its mRNA serum levels. Although circulating reduced diet-induced obese state, voluntary exercise increased expression Accordingly, up-regulated compounds (forskolin, epinephrine, ionomycin) raise cellular cAMP or calcium In vitro, secreted forms disulfide-linked oligomers, when co-expressed, heteromeric complexes with members mice, recombinant administration free acids without altering adipose tissue lipolysis. Consistent this, promoted uptake cultured adipocytes hepatocytes, part up-regulating genes (CD36, FATP1, Fabp1, Fabp4) promote lipid uptake. Collectively, these results suggest links homeostasis liver response alterations energy revealing myonectin-mediated circuit.