| BackgroundThe white adipose tissue of obese patients is often accompanied by chronic inflammation and dysfunction,which is easy to cause insulin resistance,type 2 diabetes,cardiovascular disease and so on.Macrophages are the key cells involved in the chronic inflammation of white adipose tissue in obesity.When obesity occurs,macrophages in white adipose tissue not only increase in number,but also undergo phenotypic transformation(polarization),mainly of pro-inflammatory type.Obese patients are often accompanied by hypertriglyceridemia that is particularly prominent after meals.People are in the postprandial state during the most of a day.Hypertriglyceridemia represents an increase in circulating triglyceride-rich lipoproteins(TRL).Therefore,the effect of postprandial TRL on the phenotypic transformation(polarization)of macrophages,a key inflammatory cell in white adipose tissue,is worth exploring.In addition to being an antibiotic,minocycline also shows obvious anti-inflammatory effects in skin diseases and nervous system diseases,but its effect on the phenotype of macrophages in white adipose tissue is unclear.ObjectiveTo observe the effect of postprandial TRL on macrophage polarization and inflammation,and to explore the effect and possible mechanism of minocycline on macrophage polarization co-incubated with postprandial TRL and visceral white adipose tissue.Methods1.The density-gradient ultracentrifugation was used to separate postprandial TRL from the plasma of hypertriglyceridemic patients at 4h after a high-fat meal.The protein concentration of TRL was determined by BCA assay.2.After resuscitation and passage,RAW 264.7 macrophages were incubated with phosphate buffered saline(PBS)or 100μg/m L TRL for 24 h,real-time fluorescence quantitative PCR(RT-q PCR)was used to detect the expression of macrophage phenotypic markers,inflammatory factors,antiinflammatory factor,and polarization related factors,including Chemerin and its receptor Chem R23,interferon regulatory factor 5(IRF5),monocyte chemoattractant protein inducible protein-1(MCPIP1)and silencing information regulator 2 related histone deacetylase(SIRT1).3.Postprandial TRL(100 μg/m L)with blank solvent(the control group),50 or 100 μg/m L minocycline co-incubated RAW 264.7macrophages for 24 h.RT-q PCR was used to detect the expression of macrophage phenotype markers,inflammatory factors,anti-inflammatory factor,and polarization related factors.4.The epididymal white adipose tissue(eWAT)was separated from C57BL/6J mice(5-8 weeks).When eWAT was incubated with RAW 264.7macrophages,PBS or 100μg/m L TRL was added for 24 h.RT-q PCR was used to detect the expression of macrophage phenotypic markers,inflammatory factors,anti-inflammatory factor,and polarization related factors.5.When eWAT and 100μg/m L TRL co-incubated with RAW 264.7macrophages,blank solvent,50 or 100μg/m L minocycline was added for24 h.RT-q PCR was used to detect the expression of macrophage phenotypic markers,inflammatory factors,anti-inflammatory factor,and polarization related factors.Results1.Compared with PBS,100 μg/m L postprandial TRL significantly up-regulated the gene expression of M1 phenotypic markers CD11 c,inducible nitric oxide synthase(i NOS),inflammatory factor interleukin(IL)-1 β、tumor necrosis factor(TNF-α)(P < 0.05),while significantly downregulated M2 phenotype markers CD206,arginase 1(Arg1)and antiinflammatory factor IL-10(P < 0.05).Both 50 and 100 μg/m L minocycline can reverse the effect of TRL on the phenotypic transformation and inflammatory factors expression of macrophages.It showed that postprandial TRL promoted M1 polarization while inhibited M2 polarization of macrophage.Minocycline can inhibit this effect.2.When eWAT co-incubated with RAW 264.7 macrophages,postprandial TRL significantly up-regulated the gene expression of macrophage M1 phenotypic marker i NOS,IL-1β and TNF-α(P < 0.05),while significantly down-regulated the gene expression of M2 marker CD206 and Arg1(P < 0.05).It showed that postprandial TRL promoted M1 polarization while inhibited M2 polarization of macrophage under the co-incubation with eWAT.Compared with blank solvent,50μg/m L minocycline significantly down-regulated the gene expression of CD11 c,i NOS and IL-1β、TNF-α(P < 0.05),while 100μg/m L minocycline significantly up-regulated the gene expression of CD11 c,i NOS and TNF-α(P<0.05).It suggested that low concentration minocycline inhibited while high concentration minocycline promoted the gene expression of M1 phenotypic markers in macrophages induced by TRL under the co-incubation with eWAT.3.Compared with PBS,100μg/m L TRL significantly up-regulated the gene expression of Chemerin in macrophages(P < 0.05).When compared with blank solvent,both 50 and 100μg/m L minocycline significantly upregulated the genes expression of Chemerin and Chem R23 in macrophages co-incubated with TRL(P<0.05).When eWAT co-incubated with macrophages,100μg/m L TRL significantly up-regulated the gene expression of Chemerin compared with PBS(P < 0.05).When postprandial TRL and eWAT co-incubated with macrophages,both 50 and 100μg/m L minocycline significantly downregulated the genes expression of Chemerin compared with blank solvent(P<0.05).The gene expression of Chem R23 did not change significantly.4.Compared with PBS,100μg/m L TRL significantly up-regulated the gene expression of IRF5 and MCPIP1 in macrophages,and significantly down-regulated the gene expression of SIRT1(P < 0.05).Compared with blank solvent,50μg/m L minocycline significantly down-regulated IRF5 gene expression,100μg/m L minocycline significantly up-regulated SIRT1 gene expression,and two concentrations of minocycline significantly upregulated MCPIP1 gene expression in macrophages co-incubated with TRL.When eWAT co-incubated with macrophages,100μg/m L TRL significantly up-regulated the gene expression of IRF5 and MCPIP1,while significantly down-regulated the gene expression of SIRT1 compared with PBS(P < 0.05).When postprandial TRL and eWAT co-incubated with macrophages,both 50 and 100μg/m L minocycline significantly downregulated the genes expression of IRF5.High concentration of minocycline(100μg/m L)significantly up-regulated the genes expression of SIRT1 compared with blank solvent(P<0.05),while did not significantly change the gene expression of MCPIP1.Conclusions1.Postprandial TRL promoted macrophage M1 polarization and expression of inflammatory factors,while inhibited its M2 polarization.2.Postprandial TRL may participate in eWAT inflammation by regulating macrophages polarization.3.Minocycline inhibited postprandial TRL-induced macrophage M1 polarization and expression of inflammatory factors,the specific mechanism needs to be explored.Figures 12,Tables 7,References 56... |
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