title: TLR-4/miRNA-32-5p/FSTL1 signaling regulates mycobacterial survival and inflammatory responses in Mycobacterium tuberculosis-infected macrophages.
abstract: Macrophages play a pivotal role in host immune response against mycobacterial infection, which is tightly modulated by multiple factors, including microRNAs. The purpose of the present study was to investigate the biological function and potential mechanism of miR-32-5p in human macrophages during Mycobacterium tuberculosis (M.tb) infection. The results demonstrated that miR-32-5p was robustly enhanced in THP-1 and U937 cells in response to M.tb infection. TLR-4 signaling was required for upregulation of miR-32-5p induced by M.tb infection. Additionally, the introduction of miR-32-5p strongly increased the survival rate of intracellular mycobacteria, whereas inhibition of miR-32-5p suppressed intracellular growth of mycobacteria during M.tb challenged. Furthermore, forced expression of miR-32-5p dramatically attenuated the accumulation of inflammatory cytokines IL-1β, IL-6 and TNF-α induced by M.tb infection. Conversely, downregulated expression of miR-32-5p led to enhancement in these inflammatory cytokines. More importantly, our study explored that Follistatin-like protein 1 (FSTL1) was a direct and functional target of miR-32-5p. qRT-PCR and western blot analysis further validated that miR-32-5p negatively regulated the expression of FSTL1. Mechanistically, re-expression of FSTL1 attenuated the ability of miR-32-5p to promote mycobacterial survival. Meanwhile, miR-32-5p-mediated inhibition of the inflammatory cytokine production were completely reversed by overexpression of FSTL1. Collectively, our findings demonstrated a novel role of TLR-4/miRNA-32-5p/FSTL1 in the modulation of host defense against mycobacterial infection, which may provide a better understanding of the pathogenesis of tuberculosis and useful information for developing potential therapeutic interventions against the disease.
authors.affiliation: Department of Clinical Laboratory, the Central Hospital of Zhumadian, Zhumadian, Henan 463000, PR China. Electronic address: zmzhangzmd@21cn.com.
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, the Central Hospital of Zhumadian, Zhumadian, Henan 463000, PR China.
authors.forename: Ai-Rong
authors.initials: AR
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, the Central Hospital of Zhumadian, Zhumadian, Henan 463000, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.affiliation: Department of Clinical Laboratory, the Central Hospital of Zhumadian, Zhumadian, Henan 463000, PR China.
authors.forename: Jun
authors.initials: J
authors.lastname: Lou
authors.affiliation: Department of Clinical Laboratory, the Central Hospital of Zhumadian, Zhumadian, Henan 463000, PR China.
authors.forename: Wei-Qiang
authors.initials: WQ
authors.lastname: Qiu
mesh_terms: D002460:Cell Line; D045744:Cell Line, Tumor; D038702:Follistatin-Related Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D053583:Interleukin-1beta / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000472:pathogenicity*; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
chemical_list: D038702:Follistatin-Related Proteins; D053583:Interleukin-1beta; D015850:Interleukin-6; C568529:MIRN32 microRNA, human; D035683:MicroRNAs; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; C448799:FSTL1 protein, human
keywords: Inflammatory responses; Mycobacterial survival; Mycobacterium tuberculosis (M.tb); TLR-4/miRNA-32-5p/FSTL1 signaling