The Influence Of Chemerin Oligopeptide On Wnt/β-catenin Signaling Pathway In Preadipocyte Differentiation Of Different Genotype Mice

The occurrence of obesity is associated with excessive proliferation and differentiation ofadipose tissue. Complex networks exist in the process of adipocyte differentiation. Chemerin/CMKLR1signaling pathway, Wnt/β-catenin signaling pathway and TNF-α togetherlyparticipate in adipogenesis.Knocking down chemerin inhibited adipogenesis，which reveals that chemerin plays a keyrole in adipogenesis. But the mechanisam of how chemerin affects adipogenesis has not beenreported.Activating Wnt/β-catenin signaling pathway can inhibit adipogenesis by suppressing theexpression of PPARγ. Studies have shown that skeletal muscle cells showed a decrease inGSK-3phosphorylation after incubation with exogenous chemerin. GSK-3is a keycomponent of β-catenin degradation compounds, and-catenin is a key molecule of the Wnt/β-catenin signaling pathway. Therefore, we predict that there is a crosstalk between chemerinand Wnt/β-catenin signaling pathway in adipogenesis.TNF-α is also involved in adipocyte differentiation，and it can inhibit adipogenesis. It isclosely related with chemerin and Wnt/β-catenin signaling pathway。In the experiment, four kinds of mice were used. They were WT, TNF-α-/-, Leprdb/dbandDT mice. The groin white adipose tissues were isolated and the ADSCs were cultured in vitro.And the ADSCs were treated with oligopeptide chemerin149-157. Finally the cells were fixed ortheir totol RNA or proteins were extracted in four different stages of adipogenesis(I0, I3, I7,I14). Impact of C9on the Wnt/β-catenin signaling pathway was explord on morphology andtranscriptional levels. The following conclusions can be extracted from the experiment.1. Through experiment of cell migration, proliferation, and Western-blot detection of theexpression level of pERK, it has proved that C9added in the experiment is biologically active.And10nM is the best effective concentration. 2. Through morphologic observation we detected that the orders of the final adipogenicdifferentiation rate of the four kinds of mice was：TNF-α-/->WT>DT>Leprdb/db. Besides, C9has no significant effect on the final adipogenic differentiation rate, the size and appearancetime of the lipid droplets in adipogenesis.3. Through real-time PCR experiment, we detected that C9has no significant effect on themRNA level of PPARγ, adiponectin, C/EBPα and C/EBP, which are the factors associatedwith adipogenesis. Besides, compared with the control group, C9also has no effect on themRNA level of Wnt10b and β-catenin, which are the key factors of Wnt/β-catenin signalingpathway.4. Through western blot experiment, we detected that C9has no significant effect on theprotein level of adiponectin compared with the control group. However, C9decreased theprotein level of-catenin significantly.The above results show that C9has no significant effect on the final adipogenicdifferentiation rate, the size and appearance time of the lipid droplets, the mRNA level ofPPARγ2, adiponectin, C/EBPα and C/EBP and the protein level of adiponectin. In addition,C9has no effect on the mRNA level of Wnt10b and β-catenin, which are the key factors of Wnt/β-catenin signaling pathway. But the protein level of β-catenin decreased significantly. Theabove results show that C9can promote the phosphory degradation of β-catenin. Therefore, wepredict that C9can interect with Wnt/β-catenin signaling pathway through promoting thephosphory degradation of-catenin. In addition, loss of TNF-α can weaken the impact of C9onβ-catenin phosphorylation，while obesity caused by loss of leptin receptor can enhance theimpact of C9on-catenin phosphorylation. And the mechanisam need to be further explored.