马尔尼菲篮状菌通过诱导巨噬细胞铁死亡促进炎症反应OA

Objective:To explore mechanism of ferroptosis of macrophages induced by Talaromyces marneffei(TM)infection and the impact of ferroptosis on inflammatory responses.Methods:THP-1-derived macrophages were divided into control group(Con-trol),TM spores infection 24 hours group(TM24h),and TM spores infection 24 hours+ferroptosis inhibitor Ferrostatin-1 group(TM24h+Fer-1).Transmission electron microscopy was used to observe the ultrastructural changes of cells in Control group and TM24h group.Fluorescence staining was employed to detect level of reactive oxygen species(ROS).Levels of Fe2+,malondialdehyde(MDA)and reduced glutathione(GSH)were measured using corresponding kits.Protein expressions of solute carrier family 7 member 11(SLC7A11)and glutathione peroxidase 4(GPX4)were carried out by Western blot.mRNA expression levels of acyl-CoA synthetase long chain family member 4(ACSL4),NADPH oxidase 1(NOX1),IL-6 and TNF-α were performed by qRT-PCR,and ELISA was used to detect levels of inflammatory factors IL-6,TNF-α and inducible nitric oxide synthase(iNOS).Results:Cell membranes were ruptured and bubbled,mitochondria were pyknosed,membrane density was increased,and cristae were shortened and thickened in TM24h group.Compared with Control group,expressions of ROS,Fe2+and MDA in TM24h group were markedly increased(P<0.05).Expressions of ferroptosis-related genes ACSL4 and NOX1 were also significantly increased(P<0.05),while Ferrostatin-1 treatment could reverse the above changes(P<0.05).Meanwhile,expressions of SLC7A11,GSH and GPX4 in TM24h group were significantly inhibited(P<0.05),while they were partly restored in TM24h+Fer-1 group(P<0.05).mRNA expressions of inflammatory factors IL-6 and TNF-α in TM24h group were significantly increased(P<0.05),while significantly decreased in that of TM24h+Fer-1 group(P<0.05).Accordingly,protein expressions of IL-6,TNF-α and iNOS in TM24h group were significantly increased(P<0.05),while all of them were decreased in TM24h+Fer-1 group(P<0.05).Conclusion:TM can induce ferroptosis in macrophages by inhibiting the SLC7A11/GSH/GPX4 axis,promoting inflammatory responses.Inhibiting ferroptosis can alleviate the inflammatory response caused by TM infection,providing a scientific basis for the clinical intervention of TM infection.