ABSTRACT
Objective:To investigate the regulatory effect of WNT1-inducible signaling pathway protein 2(WISP2)on macrophage polarization in palmitic acid(PA)and lipopolysaccharide(LPS)-induced inflammation.Methods:The macrophage cell line RAW264.7 was treated with different concentrations of WISP2 protein, and cell viability was determined by means of luminescence assay using Cell-Titer Glo to determine the concentration of WISP2.The cells were divided into control group, palmitic acid group, palmitic acid combined with different concentrations of WISP2 group(10 μg/L and 100 μg/L)and lipopolysaccharide group, lipopolysaccharide combined with different concentrations of WISP2 group(10 μg/L and 100 μg/L). mRNA expression of M1 and M2 macrophages phenotype of each group were detected by real-time quantitative polymerase chain reaction.The protein expression of important inflammatory factors, TNF-α and IL-6, were evaluated by ELISA.Results:Compared with the control group, both 10 μg/L and 100 μg/L WISP2 groups had no effect on the activity of RAW264.7 cells, but significantly up-regulated the expression of various inflammatory factors, including Tnfα(1.877±0.039, 2.202±0.034, F=309.7, P<0.001), Il6(1.418±0.056, 1.506±0.059, F=81.39, P<0.001), Mcp1(1.620±0.014, 1.982±0.125, F=71.45, P<0.001), Ccl3(1.892±0.118, 1.942±0.132, F=32.93, P<0.001), and iNos(1.691±0.201, 1.548±0.090, F=13.60, P<0.05). mRNA in macrophages, and significantly down-regulated the expression of anti-inflammatory factors, including Tgfβ(1.376±0.025, 2.152±0.107, F=1.846, P<0.05), CD206(2.123±0.031, 3.139±1.663, F=8.037, P<0.05), Il4(2.098±0.464, 2.494±0.141, F=48.68, P<0.01), and Il10(1.303±0.216, 1.574±0.274, F=5.774, P<0.05)mRNA, causing M1 type macrophage polarization.Compared with the control group, 100 μmol/L palmitic acid could mildly but significantly increase the expression of inflammatory factors such as TNF-α and IL-6 at the transcriptional and protein levels.Compared with palmitic acid stimulation alone, the combination of palmitic acid and WISP2 further promoted the protein expression of macrophage inflammatory factors TNF-α[(589.4±17.0)ng/L, (692.6±83.4)ng/L, F=56.38, P<0.05], IL-6[(15.13±1.14)ng/L, (13.33±1.22)ng/L, F=23.32, P<0.001]and the mRNA expression of chemokines Mcp1(160±9.796, 140±18.91, F=141.1, P<0.0001)and C cl3(17.76±1.92, 14.41±1.27, F=125.2, P<0.0001). Compared with the control group, 100 μg/L lipopolysaccharide strongly stimulated the expression of inflammatory factors such as TNF-α[(3444±423)ng/L, F=71.20, P<0.0001]and IL-6[(497.0±41.2)ng/L, F=63.50, P<0.0001]in macrophages at the protein level.Compared with lipopolysaccharide stimulation alone, the combination of lipopolysaccharide and WISP2 further significantly up-regulated the mRNA expression of chemokines Mcp1(106.8±8.7, 118.7±4.6, F=251.5, P<0.0001)and Ccl3(35.3±12.5, 116.4±4.5, F=160.1, P<0.0001). Conclusions:The adipokine WISP2 can promote M1 macrophage polarization in palmitic acid and lipopolysaccharide-induced inflammation, and it had distinct regulation in macrophage polarization under different inflammatory response conditions.
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.
ABSTRACT
Streptococcus mutans (S. mutans) is generally regarded as a major contributor to dental caries because of its ability to synthesize extracellular polysaccharides (EPS) that aid in the formation of plaque biofilm. The VicRKX system of S. mutans plays an important role in biofilm formation. The aim of this study was to investigate the effects of vicK gene on specific characteristics of EPS in S. mutans biofilm. We constructed single-species biofilms formed by different mutants of vicK gene. Production and distribution of EPS were detected through atomic force microscopy, scanning electron microscopy and confocal laser scanning microscopy. Microcosmic structures of EPS were analyzed by gel permeation chromatography and gas chromatography-mass spectrometry. Cariogenicity of the vicK mutant was assessed in a specific pathogen-free rat model. Transcriptional levels of cariogenicity-associated genes were confirmed by quantitative real-time polymerase chain reaction. The results showed that deletion of vicK gene suppressed biofilm formation as well as EPS production, and EPS were synthesized mostly around the cells. Molecular weight and monosaccharide components underwent evident alterations. Biofilms formed in vivo were sparse and contributed a decreased degree of caries. Moreover, expressional levels of genes related to EPS synthesis were down-regulated, except for gtfB. Our report demonstrates that vicK gene enhances biofilm formation and subsequent caries development. And this may due to its regulations on EPS metabolism, like synthesis or microcosmic features of EPS. This study suggests that vicK gene and EPS can be considered as promising targets to modulate dental caries.