| Background:Tuberculosis(TB)is a chronic infectious disease which causes by Mycobacterium tuberculosis(Mtb).Until the COVID-19 pandemic,TB was the leading single uniformly fatal infectious disease,killing more people than AIDS.Dendritic cells(DCs)are the only professional antigen presenting cells that can activate naive T cells.They play an important role in antigen processing and presentation.They are also key cells connecting innate immunity and adaptive immunity,and play an important role in anti-Mtb infection.microRNAs(miRNAs)are non-coding single-stranded RNA molecule with a length of about 22 nucleotides.By acting on the 3’-UTR of the target mRNA,miRNA can lead to the degradation of the target mRNA or inhibit its translation,and play a post-transcriptional regulatory role.In recent years,it has been reported that miRNAs are closely related to the pathogenesis of Mtb infection.Various studies have revealed the changes of miRNAs in host cells after infection with Mtb,indicating that miRNAs play a crucial role in guiding the immune response to TB infection.Our research group previously found that miRNA-1 expression was significantly increased in DCs of people infected with Mtb.miRNA-1 is a conservative miRNA mainly expressed in muscle tissue.In addition to playing a key role in the physiological process of muscle tissue,miRNA-1 also regulates multiple functions of other tissues and participates in the pathogenesis of many diseases.However,whether miR-1 is also involved in the regulation of TB infection immunity in DCs remains unknown and needs further study.Methods:1.Quantitative Real-time fluorescence PCR(qRT-PCR)was used to detect the expression of miR-1-3p(Know as miR-1)in Mtb-infected human peripheral blood derived dendritic cells(HMDC);2.The killing effect of miR-1 on Mtb was determined in vivo experiment in mice.Colony-forming unit(CFU)experiment was used to detect the bacteria load in spleen and lung of mice at the first and fourth week after Mtb infection.Cytokines secretion levels in eye blood,spleen and lung tissue supernatant at week 1 and 4 after Mtb infection were detected by Enzyme linked immunosorbent assay(ELISA);3.The expression levels of inflammatory cytokines and chemokines in Mtb-infected BMDC were detected by qRT-PCR and ELISA;4.The effect of miR-1 on antigen phagocytosis and antigen processing ability of BMDC was detected by flow cytometry;5.Flow cytometry was used to detect the expression levels of CD80,CD86,CD40 and MHC Ⅱ in Mtb-infected BMDC;6.The effect of miR-1 on the activation of CD4+T cells by BMDC was determined by flow cytometry.7.The reported mRNA expression levels of lncRNA Srosl and downstream Statl regulated by miR-1 were detected by qRT-PCR.Results:1.miR-1-3p(Know as miR-1)expression was increased in Mtb-infected HMDC;2.In vivo experiments of mice showed that miR-1 can promote the killing of Mtb and the secretion of IFN-γ at the same time;3.miR-1 promoted the expression of IL-12 in BMDCS after Mtb infection,and inhibited the expression of IL-10,related chemokines and chemokine receptors;4.miR-1 inhibits antigen-phagocytosis and antigen-processing capacity of BMDC;5.miR-1 promotes the expression of surface co-stimulatory molecules CD80,CD86,CD40 and MHC Ⅱ of BMDC after Mtb infection;6.miR-1 promotes the ability of BMDC to activate CD4+ T cells;7.miR-1 inhibited Srosl expression and promoted Statl mRNA expression in BMDC after Mtb infection.Conclusions:In this study,it was found that miR-1-3p(Know as miR-1)was increased in dendritic cells derived from mononuclear cells in peripheral blood of people infected with Mtb.In vivo experiments in mice showed that miR-1 can promote the killing of Mtb and the secretion of cytokines,and enhance the anti-tuberculosis effect of the body.Further elucidate the immunoregulatory role and mechanism of miR-1 in tuberculosis will guide more precise treatment and promote clinical treatment progress. |
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