PLoS One
·
2014
·Vol. 9
·期 4
·e94418
·
IF 3.534
Wu Li,Quanju Zhao,Wanyan Deng,Tian Chen,Minqiang Liu,Jianping Xie
Intracellular survival plays a central role in the pathogenesis of Mycobacterium tuberculosis , a process which depends on an array of virulence factors to colonize and replicate within the host. The M. tuberculosis iron regulated open reading frame (ORF) rv3402c , encoding a conserved hypothetical protein, was shown to be up-regulated upon infection in both human and mice macrophages. To explore the function of this ORF, we heterologously expressed the rv3402c gene in the non-pathogenic fast-growing Mycobacterium smegmatis strain, and demonstrated that Rv3402c, a cell envelope-associated protein, was able to enhance the intracellular survival of recombinant M. smegmatis . Enhanced growth was not found to be the result of an increased resistance to intracellular stresses, as growth of the Rv3402c expressing strain was unaffected by iron depletion, H 2 O 2 exposure, or acidic conditions. Colonization of macrophages by M. smegmatis expressing Rv3402c was associated with substantial cell death and significantly greater amount of TNF-α and IL-1β compared with controls. Rv3402c-induced TNF-α and IL-1β production was found to be mediated by NF-κB, ERK and p38 pathway in macrophages. In summary, our study suggests that Rv3402c delivered in a live M. smegmatis vehicle can modify the cytokines profile of macrophage, promote host cell death and enhance the persistence of mycobacterium within host cells.
研究领域:
微生物学
·
免疫学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2023
·Vol. 24
·期 13
·10744
·
IF 5.6
Mingyue Hao,Minghui Wang,Danyu Zhao,Yong Shi,Ye Yuan,Junmei Li,Yunyi Zhai,Xiaofang Liu,Dong Zhou,Huatao Chen,Pengfei Lin,Keqiong Tang,Wei Liu,Yaping Jin,Aihua Wang
Brucella suis, the causative agent of brucellosis, poses a significant public health and animal husbandry threat. However, the role of the alanine racemase (alr) gene, which encodes alanine racemase inBrucella, remains unclear. Here, we analyzed analrdeletion mutant and a complemented strain ofBrucella suisS2. The knockout strain displayed an unaltered, smooth phenotype in acriflavine agglutination tests but lacked the core polysaccharide portion of lipopolysaccharide (LPS). Genes involved in the LPS synthesis were significantly upregulated in the deletion mutant. Thealrdeletion strain exhibited reduced intracellular viability in the macrophages, increased macrophage-mediated killing, and upregulation of the apoptosis markers. Bcl2, an anti-apoptotic protein, was downregulated, while the pro-apoptotic proteins, Bax, Caspase-9, and Caspase-3, were upregulated in the macrophages infected with the deletion strain. The infected macrophages showed increased mitochondrial membrane permeability, Cytochrome C release, and reactive oxygen species, activating the mitochondrial apoptosis pathway. These findings revealed that alanine racemase was dispensable inB. suisS2 but influenced the strain’s rough features and triggered the mitochondrial apoptosis pathway during macrophage invasion. The deletion of thealrgene reduced the intracellular survival and virulence. This study enhances our understanding of the molecular mechanism underlyingBrucella’s survival and virulence and, specifically, howalrgene affects host immune evasion by regulating bacterial LPS biosynthesis.Keywords:Brucella suisS2;alanine racemase;alr;lipopolysaccharide;apoptosis;mitochondrial membrane potential;intracellular survival
研究领域:
微生物学
·
分子生物学
·
传染病学
·
免疫学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INFECTION GENETICS AND EVOLUTION
·
2019
·
IF 2.611
Cao Ruan,Jiang Li,Jingjing Niu,Ping Li,Yu Huang,Xue Li,Wei Duan,Shuangquan Yan,Junfeng Zhen,Jianping Xie
Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) is still a leading cause of death worldwide. M. tuberculosis has evolved multipronged strategies to subvert host immune defenses and establish an immunologically privileged niche in macrophages. Rv0426c has been predicted to be an effector involved in the Mtb-host interactions. To investigate the potential role played by Rv0426c, we constructed recombinant M. smegmatis strains with heterologous expression of Rv0426c. We observed that Rv0426c recombinants became more susceptible to various stresses by increasing cell wall permeability, however with elevated early survival rate within macrophages. This was accompanied by decreased levels of pro-inflammatory cytokines and host cell apoptosis . The data suggested that Rv0426c was a new player involved in the interactions between Mtb and macrophages.
研究领域:
微生物学
·
免疫学
·
传染病学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MICROBIOLOGY
·
2024
·Vol. 62
·期 1
·49-62
·
IF 3.3
Xu Tao,Wang Chutong,Li Minying,Wei Jing,He Zixuan,Qian Zhongqing,Wang Xiaojing,Wang Hongtao
Tuberculosis (TB), a bacterial infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis ), is a significant global public health problem. Mycobacterium tuberculosis expresses a unique family of PE_PGRS proteins that have been implicated in pathogenesis. Despite numerous studies, the functions of most PE_PGRS proteins in the pathogenesis of mycobacterium infections remain unclear. PE_PGRS45 (Rv2615c) is only found in pathogenic mycobacteria. In this study, we successfully constructed a recombinant Mycobacterium smegmatis ( M. smegmatis ) strain which heterologously expresses the PE_PGRS45 protein. We found that overexpression of this cell wall-associated protein enhanced bacterial viability under stress in vitro and cell survival in macrophages. MS_PE_PGRS45 decreased the secretion of pro-inflammatory cytokines such as IL-1β, IL-6, IL-12p40, and TNF-α. We also found that MS_PE_PGRS45 increased the expression of the anti-inflammatory cytokine IL-10 and altered macrophage-mediated immune responses. Furthermore, PE_PGRS45 enhanced the survival rate of M. smegmatis in macrophages by inhibiting cell apoptosis. Collectively, our findings show that PE_PGRS45 is a virulent factor actively involved in the interaction with the host macrophage.
研究领域:
微生物学
·
免疫学
·
传染病学
✓ 已验证
DOI
高影响因子
Frontiers in Cellular and Infection Microbiology
·
2020
·
IF 4.123
Ali Md Kaisar,Zhen Gong,Nzungize Lambert,Stojkoska Andrea,Duan Xiangke,Li Chunyan,Duan Wei,Xu Junqi,Xie Jianping
The Mycobacterium (M.) tuberculosis comprising proline–glutamic acid (PE) subfamily proteins associate with virulence, pathogenesis, and host-immune modulations. While the functions of most of this family members are not yet explored. Here, we explore the functions of “PE only” subfamily member PE31 (Rv3477) in virulence and host-pathogen interactions. We have expressed the M. tuberculosis PE31 in non-pathogenic Mycobacterium smegmatis strain (Ms_PE31) and demonstrated that PE31 significantly altered the cell facet features including colony morphology and biofilm formation. PE31 expressing M. smegmatis showed more resistant to the low pH, diamide, H2O2 and surface stress. Moreover, Ms_PE31 showed higher intracellular survival in macrophage THP-1 cells. Ms_PE31 significantly down-regulated the production of IL-12p40 and IL-6, while up-regulates the production of IL-10 in macrophages. Ms_PE31 also induced the expression of guanylate-binding protein-1 (GBP-1) in macrophages. Further analysis demonstrates that Ms_PE31 inhibits the caspase-3 activation and reduces the macrophages apoptosis. Besides, the NF-κB signaling pathway involves the interplay between Ms_PE31 and macrophages. Collectively, our finding identified that PE31 act as a functionally relevant virulence factor of M. tuberculosis.
研究领域:
微生物学
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免疫学
·
病原学
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宿主-病原体相互作用
·
细胞生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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