ABSTRACT
Objective:To investigate the effects of various concentrations of recombinant human WISP2 protein(WISP2)on lipid metabolism in HepG2 cells.Methods:HepG2 cells were treated with different concentrations(0, 0.4, 1 and 2 μg/L)of recombinant human WISP2 for 48 hours.Cell viability was detected by Cell-Titer, and enzymatic hydrolysis methods were used to measure intracellular triacylglycerol(TG)and total cholesterol(TC)levels.The mRNA expression was detected by quantitative real-time reverse transcription-PCR(RT-qPCR)and protein expression in HepG2 cells was detected by western blot.Results:Compared with the control group, the WISP2 groups treated with various concentration did not significantly reduce the viability of HepG2 cells.TG and TC in HepG2 cells were significantly increased by recombinant human WISP2 treatment(all P<0.05).The concentrations of TG in the 0.4, 1 and 2 μg/L recombinant human WISP2-treated groups were 1.254±0.039, 1.216±0.028 and 1.174±0.014)times the concentration in the untreated group, respectively( F=6.791, P=0.006).The concentration of TC in the untreated group was 1.264±0.057, 1.394±0.101 and 1.392±0.077), respectively, times the concentration in each of the treated groups( F=7.045, P=0.005).Further experiments found that the mRNA expression of sterol regulatory element binding protein 1(SREBP1), 3-hydroxy-3-methylglutaryl coenzyme A reductase(HMGCR), acetyl-CoA carboxylase(ACC), type 2 diacylglycerol acyltransferase(DGAT2)and the protein expression of SREBP1, ACC and fatty acid synthase(FAS)were significantly increased in the recombinant human WISP2-treated groups, compared with the control group(all P<0.05).However, the expression of lipid transporters such as the low-density lipoprotein receptor(LDLR), ApoB and ApoE and adipose triglyceride lipase(ATGL), a key lipolysis protein, was not significantly affected. Conclusions:Human recombinant WISP2 protein increases lipid levels in hepatocytes and the key underlying mechanisms may be through promoting lipid synthesis.