The Mechanism Of Treating Pulmonary Fibrosis With Curcumin By Inhibiting NLRP3-IL-1? Pathway

Objective:To elucidate the molecular mechanism of curcumin in improving the progression of silicosis fibrosis by blocking the activation of NLRP3 inflamemosomes inalveolar macrophages and down-regulating the secretion of IL-1?,IL-18 and other inflammatory factors in lung tissues.Methods:The mouse model of silicosis induced by one-time tracheal injection of SiO2 was constructed.The contents of NLRP3 inflammatory cortisone-related inflammatory factorsIL-1?,IL-18 and pulmonary fibrosis related indicators TGF-?1 and hydroxyproline in the pulmonary tissues of silicosis fibrosis mice after drug intervention were detected,and the pathological changes of pulmonary fibrosis in each group were observed and compared to explore the therapeutic effect of curcumin on silicosis fibrosis.Furthermore,the specific molecular mechanism of blocking the activation of NLRP3 inflammomes and inhibiting the secretion of IL-1? and IL-18 by curcumin was further studied by using qRT-PCR,Western-Blot,ELISA,Immunofluorescence,and Flow cytometry on the model of alveolar macrophage stimulated by SiO2.Finally,the potential molecular targets of curcumin were screened by SPR-MS technique.Results:(1)Curcumin water decoction and curcumin each dose,especially of curcumin in dosage,high-dose intervention can effectively suppress the secretion of inflammatory factor in mice induced by SiO2 stimulus IL-1? and IL-18,further testing found that curcumin in large dose and medium dose group mice lung pulmonary fibrosis index TGF-?1,hydroxyproline content dropped significantly,and this two groups of mice lung tissue pathology degree of inflammation and fibrosis were improved significantly in the model group.(2)Curcumin has inhibitory activity on the transcriptional level of NLRP3 inflamma-related genes in the model of SiO2-induced macrophage inflammatory response,suggesting that it inhibits the NF-?B pathway.But curcuminshowed more obvious inhibition toCaspase-1 shear and IL-1?,IL-18 secretion than NF-?B pathway inhibitor TPCA-1,hints of curcumin in addition to the mechanism of inhibiting inflammatory corpuscle NLRP3 activation through the NF-?B pathway inhibition of NLRP3 related gene transcription,possibly through other unknown way to NLRP3 inflammatory corpuscle activation directly exert inhibitory effect.(3)Curcumin intervention can effectively reverse the lysosomal damage and cell acidification induced by SiO2 stimulation;Furthermore,the assembly and activation of NLRP3 inflammatory complex were blocked by affecting the mitochondrial transport function of stimulated cells to prevent mitochondrial turnover and aggregation to the nucleus.Mitochondrial membrane potential test showed that curcumin could improve the mitochondrial stability of stimulated cells,suggesting that the function of curcumin in preventing mitochondrial translocation aggregation may be related to the improvement of mitochondrial stability.(4)Sixty-three candidate curcumin target proteins were screened by SRP-MS,including 7 functional proteins related to mitochondrial function and 19 functional enzymes.These results provides the foundation for further identification of curcumin target proteins.Conclusion:(1)Curcumin intervention medication can significantly reduce the contents of inflammatory factors IL-1?,IL-18,and fibrosis indicators TGF-?1 and hydroxyproline in the lung tissues of silicon-dust stained mice,thereby improving symptoms of the pulmonary fibrosis in mice.(2)The mechanism by which curcumin blocks the activation of NLRP3 inflammitisconsists of two aspects:on the one hand,it inhibits the activation of NF-?B pathway in cells,and down-regulates the expression of related genes from the transcriptional level;On the other hand,curcumin directly blocks activation,assembly,and downstream molecular shearing of NLRP3 inflammasomes.(3)The mechanism by which curcumin directly blocks the activation of NLRP3 inflammomes is related to the prevention of lysosomal destruction and the activation of NLRP3 inflammomes by cell acidification.On the other hand,by stabilizing mitochondrial membrane potential and preventing mitochondrial redistribution and aggregation caused by mitochondrial dysfunction,the assembly of NLRP3 inflammatitis protein complex was blocked.(4)The potential intracellular protein targets of curcumin were obtained through molecular fishing screening,which provided a research basis for further identification and verification of the targets of curcumin and revealing the pharmacological action mechanism of curcumin at the molecular level.