C1qTNF-related protein-6 increases the expression of interleukin-10 in macrophages
MOLECULES AND CELLS
Authors: Kim, Mi-Jin; Lee, Wan; Park, Eun-Ju; Park, Seung-Yoon
Abstract
C1qTNF-Related proteins (CTRPs), a new highly conserved family of adiponectin paralogs, were recently identified as being involved in diverse processes including metabolism, host defense, apoptosis, cell differentiation, and organogenesis. However, the functional role of CTRP6 remains poorly identified. Here we provide evidence that CTRP6 induces the expression of interleukin-10 (IL-10) in macrophages. Conditioned medium from CTRP6-expressing HEK293 cells increased IL-10 expression in Raw264.7 cells. The globular domain of CTRP6 (gCTRP6) also dose-dependently increased both IL-10 mRNA and protein expression levels, with transcript levels increasing within 2 h. Furthermore, the globular domain of CTRP6 rapidly induced phosphorylation of ERK1/2 in Raw264.7 cells. Treatment with U0126, a selective inhibitor, abolished CTRP6-stimulated IL-10 induction. Taken together, there results demonstrate that CTRP6 induces expression of IL-10 via ERK1/2 activation. Considering that IL-10 is a potent anti-inflammatory cytokine that modulates inflammatory signaling pathways, CTRP6 may be a novel target for pharmacological drugs in inflammatory diseases.
Lipogenesis in myoblasts and its regulation of CTRP6 by AdipoR1/Erk/PPAR gamma signaling pathway
ACTA BIOCHIMICA ET BIOPHYSICA SINICA
Authors: Wu, Wenjing; Sun, Yunmei; Zhao, Chen; Zhao, Cunzhen; Chen, Xiaochang; Wang, Guoqiang; Pang, Weijun; Yang, Gongshe
Abstract
The induced lipogenesis and its regulation in C2C12 myoblasts remain largely unclear. Here, we found that the cocktail method could significantly induce lipogenesis through regulating lipid metabolic genes and Erk1/2 phosphorylation in myoblasts. Meanwhile, the expression and secretion of CTRP6 were increased during ectopic lipogenesis. Moreover, CTRP6 knockdown downregulated the levels of lipogenic genes and phosphorylated Erk1/2 (p-Erk1/2) in the early lipogenic stage, whereas up-regulated p-Erk1/2 in the terminal differentiation. Interestingly, the effect of CTRP6 siRNA was attenuated by U0126 (a special p-Erk1/2 inhibitor) in myoblasts. Furthermore, AdipoR1, not AdipoR2, was first identified as a receptor of CTRP6 during the process of mitotic clonal expansion. Collectively, we suggest that CTRP6 mediates the ectopic lipogenesis through AdipoR1/Erk/PPAR gamma signaling pathway in myoblasts. Our findings will shed light on the novel biological function of CTRP6 during myoblast lipogenesis and provide a hopeful direction of improving meat quality of domestic animal by lipogenic regulation in skeletal muscle myoblasts.