ABSTRACT
Objective To investigate the effect of Trichomonas vaginalis macrophage migration inhibitory factor (TvMIF) on THP-1 macrophages.. Methods Recombinant TvMIF protein was prokaryotic expressed and purified, and endotoxin was removed after identification. Following exposure to TvMIF at concentrations of 0, 1, 5, 10, 50 and 100 ng/mL, the cytotoxicity of the recombinant TvMIF protein to THP-1 macrophages was tested using cell counting kit (CCK)-8 assay, and the apoptosis of THP-1 macrophages and reactive oxygen species (ROS) were detected using flow cytometry. The relative expression of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), caspase-1, interleukin-1β (IL-1β) and IL-18 genes was quantified using real-time fluorescent quantitative PCR (qPCR) assay, and the expression of caspase-1, NLRP3, gasdermin D (GSDMD), gasdermin D N-terminal (GSDMD-NT) and pro-IL-1β proteins were determined using Western blotting assay. Results Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) displayed successful expression and purification of the recombinant TvMIF protein with a molecular weight of 15.5 kDa, and the endotoxin activity assay showed the successful removal of endotoxin in the recombinant TvMIF protein (endotoxin concentration < 0.1 EU/mL), which was feasible for the subsequent studies on protein functions. Flow cytometry revealed that the recombinant TvMIF protein at a concentration of 10 ng/mL and less promoted the apoptosis of THP-1 macrophages, and the highest apoptotic rate of THP-1 macrophages was seen following exposure to the recombinant TvMIF protein at a concentration of 5 ng/mL, while the recombinant TvMIF protein at concentrations of 50 and100 ng/mL inhibited the apoptosis of THP-1 macrophages. Exposure to the recombinant TvMIF protein at a concentration 1 ng/mL resulted in increased ROS levels in THP-1 macrophages. qPCR assay quantified significantly elevated caspase-1, NLRP3, IL-18 and IL-1β expression in THP-1 macrophages 8 hours post-treatment with the recombinant TvMIF protein at a concentration 1 ng/mL, and Western blotting determined increased caspase-1, NLRP3, pro-IL-1β, GSDMD and GSDMD-NT protein expression in THP-1 macrophages following exposure to the recombinant TvMIF protein at a concentration 1 ng/mL. Pretreatment with MCC950 significantly reduced GSDMD and GSDMD-NT protein expression. Conclusions High-concentration recombinant TvMIF protein inhibits macrophage apoptosis, while low-concentration recombinant TvMIF protein activates NLRP3 inflammasome and promotes macrophage pyroptosis.
ABSTRACT
Objective@#To investigate the effects of β2 glycoprotein Ⅰ/anti-β2 glycoprotein Ⅰ complex (β2/aβ2) on oxidized low density lipoprotein (oxLDL)-mediated lipid accumulation and focal adhesion kinase (FAK) activation in THP-1 macrophage, as well as the role of Toll-like receptor 4 (TLR4) during the process. @*Methods@#THP-1 cells were differentiated into THP-1 macrophage by PMA (100 ng/mL). THP-1 macrophages were treated with RPMI 1640 medium, oxLDL, oxLDL+β2/aβ2 or oxLDL+lipopolysaccharide (LPS). The mRNA expressions of lipid transportation molecules, ACAT1, ABCA1 and ABCG1 were detected by RT-qPCR. Intracellular total cholesterol (TC) and free cholesterol (FC) in THP-1 macrophages were evaluated by Trinder assay, then the content and proportion of intracellular cholesteryl ester (CE) were calculated. The expression and phosphorylation of FAK were detected by immune fluorescence, RT-qPCR and western blot. To evaluate the role of TLR4, THP-1 macrophages were pre-treated with or without TLR4 inhibitor TAK-242 (1 μg/mL). @*Results@#β2/aβ2 treatment significantly inhibited oxLDL-mediated lipid accumulation and FAK expression and phosphorylation in THP-1 macrophages, which could be reversed by TLR4 blockage. @*Conclusion@#β2/aβ2 inhibits the oxLDL-mediated lipid accumulation and FAK activation of THP-1 macrophage, which is related to the function of TLR4.
ABSTRACT
Toxoplasma gondii is an obligate intracellular parasite that stimulates production of high levels of proinflammatory cytokines, which are important for innate immunity. NLRs, i.e., nucleotide-binding oligomerization domain (NOD)-like receptors, play a crucial role as innate immune sensors and form multiprotein complexes called inflammasomes, which mediate caspase-1-dependent processing of pro-IL-1β. To elucidate the role of inflammasome components in T. gondii-infected THP-1 macrophages, we examined inflammasome-related gene expression and mechanisms of inflammasome-regulated cytokine IL-1β secretion. The results revealed a significant upregulation of IL-1β after T. gondii infection. T. gondii infection also upregulated the expression of inflammasome sensors, including NLRP1, NLRP3, NLRC4, NLRP6, NLRP8, NLRP13, AIM2, and NAIP, in a time-dependent manner. The infection also upregulated inflammasome adaptor protein ASC and caspase-1 mRNA levels. From this study, we newly found that T. gondii infection regulates NLRC4, NLRP6, NLRP8, NLRP13, AIM2, and neuronal apoptosis inhibitor protein (NAIP) gene expressions in THP-1 macrophages and that the role of the inflammasome-related genes may be critical for mediating the innate immune responses to T. gondii infection.
Subject(s)
Apoptosis , Cytokines , Gene Expression , Immunity, Innate , Inflammasomes , Macrophages , Multiprotein Complexes , Negotiating , Neurons , Parasites , RNA, Messenger , Toxoplasma , Up-RegulationABSTRACT
Objective: To investigate the effect of oxLDL on CD36 expression and cholesterol influx in THP-1 macrophage. Methods: THP1 macrophage were treated with 50mg/L oxLDL for 0,12,24,36,48 h respectively.Oil red O staining was used to observe the intracellular lipid droplets.\labeled Cholesterol influx was determined by FJ-2107P type liquid scintillator.CD36 mRNA and protein level were determined by reverse transcription-polymerase chain reaction(RT-PCR) and Western blotting respectively. Results:We found that oxLDL elevated CD36 in both protein and mRNA levels and increased cholesterol influx in a time-dependent manner.The levels of cholesterol influx were 23.5%、(27.8%、)39.7%、44.1% and 49.7% respectively. Conclusion: oxLDL may upregulate CD36 expression and increase cholesterol influx.