Dataset Information

Rv3722c Promotes Mycobacterium tuberculosis Survival in Macrophages by Interacting With TRAF3.

ABSTRACT: Mycobacterium tuberculosis (M.tb) secretes numerous proteins to interfere with host immune response for its long-term survival. As one of the top abundant M.tb secreted proteins, Rv3722c was found to be essential for bacilli growth. However, it remains elusive how this protein interferes with the host immune response and regulates M.tb survival. Here, we confirmed that Rv3722c interacted with host TRAF3 to promote M.tb replication in macrophages. Knock-down of TRAF3 attenuated the effect of Rv3722c on the intracellular M.tb survival. The interaction between Rv3722c and TRAF3 hampered MAPK and NF-?B pathways, resulting in a significant increase of IFN-? expression and decrease of IL-1?, IL-6, IL-12p40, and TNF-? expression. Our study revealed that Rv3722c interacted with TRAF3 and interrupted its downstream pathways to promote M.tb survival in macrophages. These findings facilitate further understanding of the mechanism of M.tb secreted proteins in regulating the host cell immune response and promoting its intracellular survival.

SUBMITTER: Lei Y

PROVIDER: S-EPMC7947218 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature

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Rv3722c Promotes Mycobacterium tuberculosis Survival in Macrophages by Interacting With TRAF3.

Lei Yingying Y Cao Xiaojian X Xu Weize W Yang Bing B Xu Yangyang Y Zhou Wei W Dong Shuang S Wu Qijun Q Rahman Khaista K Tyagi Rohit R Zhao Shuhong S Chen Xi X Cao Gang G

Frontiers in cellular and infection microbiology 20210225

Mycobacterium tuberculosis (M.tb) secretes numerous proteins to interfere with host immune response for its long-term survival. As one of the top abundant M.tb secreted proteins, Rv3722c was found to be essential for bacilli growth. However, it remains elusive how this protein interferes with the host immune response and regulates M.tb survival. Here, we confirmed that Rv3722c interacted with host TRAF3 to promote M.tb replication in macrophages. Knock-down of ...[more]

PMID: 33718275

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Project description:Tuberculosis (TB) is caused by Mycobacterium tuberculosis (M. tuberculosis) infection and has the highest mortality rate of any single infectious disease worldwide. The aim of the present study was to investigate the function of microRNA (miR)‑502‑3p in M. tuberculosis‑infected macrophages. The Gene Expression Omnibus database was used to analyze miR‑502‑3p expression in patients with TB and healthy individuals. THP‑1 and RAW 264.7 cells were transfected with miR‑502‑3p mimic, miR‑502‑3p inhibitor, pcDNA3.1‑ROCK1 or their negative controls. The expression levels of miR‑502‑3p and inflammatory cytokines were evaluated using reverse transcription‑quantitative PCR. The colony‑forming unit assay was performed to assess the survival of M. tuberculosis in macrophages, and Toll‑like receptor (TLR)4/NF‑κB signaling pathway‑associated protein expression levels were detected by western blotting. The nuclear translocation of NF‑κB p65 was detected via immunocytochemistry. TargetScan was used to predict the binding sites between miR‑502‑3p and ROCK1. The interaction between miR‑502‑3p and Rho‑associated coiled‑coil‑forming protein kinase 1 (ROCK1) was confirmed using a dual‑luciferase reporter assay; ROCK1 was demonstrated to be a direct target gene of miR‑502‑3p. Results from the present study demonstrated that miR‑502‑3p expression was significantly increased during M. tuberculosis infection in macrophages. Upregulation of miR‑502‑3p expression levels significantly enhanced the survival of intracellular M. tuberculosis. IL‑6, TNF‑α, and IL‑1β mRNA expression levels were significantly upregulated during M. tuberculosis infection but were downregulated by miR‑502‑3p overexpression. Moreover, miR‑502‑3p mimics transfection significantly downregulated TLR4/NF‑κB signaling pathway‑associated protein expression and significantly reduced nuclear transcription of NF‑κB in M. tuberculosis‑infected macrophages. ROCK1 overexpression reversed the miR‑502‑3p inhibitory effect on cytokine production in M. tuberculosis‑infected macrophages. In conclusion, miR‑502‑3p/ROCK1 may serve an anti‑inflammatory role and may improve the survival of M. tuberculosis within macrophages, which may provide a promising therapeutic target for TB.

Project description:Intracellular survival plays a central role in the pathogenesis of Mycobacterium tuberculosis. To identify M. tuberculosis genes required for intracellular survival within macrophages, an M. tuberculosis H37Rv plasmid library was constructed by using the shuttle vector pOLYG. This plasmid library was electroporated into Mycobacterium smegmatis 1-2c, and the transformants were used to infect the human macrophage-like cell line U-937. Because M. smegmatis does not readily survive within macrophages, any increased intracellular survival is likely due to cloned M. tuberculosis H37Rv DNA. After six sequential passages of M. smegmatis transformants through U-937 cells, one clone (p69) was enriched more than 70% as determined by both restriction enzyme and PCR analyses. p69 demonstrated significantly enhanced survival compared to that of the vector control, ranging from 2.4- to 5.3-fold at both 24 and 48 h after infection. DNA sequence analysis revealed three open reading frames (ORFs) in the insert of p69. ORF2 (1.2 kb) was the only one which contained a putative promoter region and a ribosome-binding site. Deletion analysis of the p69 insert DNA showed that disruption of ORF2 resulted in complete loss of the enhanced intracellular survival phenotype. This gene was named the enhanced intracellular survival (eis) gene. By using an internal region of eis as a probe for Southern analysis, eis was found in the genomic DNA of various M. tuberculosis strains and of Mycobacterium bovis BCG but not in that of M. smegmatis or 10 other nonpathogenic mycobacterial species. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis showed that all M. smegmatis eis-containing constructs expressed a unique protein of 42 kDa, the predicted size of Eis. The expression of this 42-kDa protein directly correlated to the enhanced survival of M. smegmatis p69 in U-937 cells. These results suggest a possible role for eis and its protein product in the intracellular survival of M. tuberculosis.

Dataset Information

Rv3722c Promotes Mycobacterium tuberculosis Survival in Macrophages by Interacting With TRAF3.

Publications

Rv3722c Promotes <i>Mycobacterium tuberculosis</i> Survival in Macrophages by Interacting With TRAF3.

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