Dataset Information

Mycobacterium tuberculosis PE_PGRS41 Enhances the Intracellular Survival of M. smegmatis within Macrophages Via Blocking Innate Immunity and Inhibition of Host Defense.

ABSTRACT: The success of Mycobacterium tuberculosis (M. tuberculosis) as a pathogen is largely contributes to its ability to manipulate the host immune responses. The genome of M. tuberculosis encodes multiple immune-modulatory proteins, including several members of the multi-genic PE_PPE family. Despite of intense research, the roles of PE_PGRS proteins in mycobacterial pathogenesis remain elusive. The function of M. tuberculosis PE_PGRS41, characterized by an extended and unique C-terminal domain, was studied. Expression of PE_PGRS41 in Mycobacterium smegmatis, a non-pathogenic species intrinsically deficient of PE_PGRS, severely impaired the resistance of the recombinant to multiple stresses via altering the cell wall integrity. Macrophages infected by M. smegmatis harboring PE_PGRS41 decreased the production of TNF-?, IL-1? and IL-6. In addition, PE_PGRS41 boosted the survival of M. smegmatis within macrophage accompanied with enhanced cytotoxic cell death through inhibiting the cell apoptosis and autophagy. Taken together, these results implicate that PE_PGRS41 is a virulence factor of M. tuberculosis and sufficient to confer pathogenic properties to M. smegmatis.

SUBMITTER: Deng W

PROVIDER: S-EPMC5404228 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature

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Mycobacterium tuberculosis PE_PGRS41 Enhances the Intracellular Survival of M. smegmatis within Macrophages Via Blocking Innate Immunity and Inhibition of Host Defense.

Deng Wanyan W Long Quanxin Q Zeng Jie J Li Ping P Yang Wenmin W Chen Xinchun X Xie Jianping J

Scientific reports 20170425

The success of Mycobacterium tuberculosis (M. tuberculosis) as a pathogen is largely contributes to its ability to manipulate the host immune responses. The genome of M. tuberculosis encodes multiple immune-modulatory proteins, including several members of the multi-genic PE_PPE family. Despite of intense research, the roles of PE_PGRS proteins in mycobacterial pathogenesis remain elusive. The function of M. tuberculosis PE_PGRS41, characterized by an extended and unique C-terminal domain, was s ...[more]

PMID: 28440335

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Project description:Pulmonary infection of humans by Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), results in active disease in 5-10% of individuals, while asymptomatic latent Mtb infection (LTBI) is established in the remainder. The host immune responses that determine this differential outcome following Mtb infection are not fully understood. Using a rabbit model of pulmonary TB, we have shown that infection with the Mtb clinical isolate HN878 (a hyper-virulent W-Beijing lineage strain) leads to progressive cavitary disease similar to what is seen in humans with active TB. In contrast, infection with Mtb CDC1551 (a hyper-immunogenic clinical isolate) is efficiently controlled in rabbit lungs, with establishment of LTBI, which can be reactivated upon treatment with immune-suppressive drugs. We hypothesize that the initial interaction of Mtb with the cells of the host response in the lungs determine later outcome of infection.To test this hypothesis, we used our rabbit model of pulmonary TB and infected the animals with Mtb HN878 or CDC1551. At 3 hours, with similar lung bacillary loads, HN878 infection caused greater accumulation of mononuclear and polymorphonuclear leukocytes (PMN) in the lungs, compared to animals infected with CDC1551. Using whole-genome microarray gene expression analysis, we delineated the early transcriptional changes in the lungs of HN878- or CDC1551-infected rabbits at this time and compared them to the differential response at 4 weeks of Mtb-infection. Our gene network and pathway analysis showed that the most significantly differentially expressed genes involved in the host response to HN878, compared to CDC1551, at 3 hours of infection, were components of the inflammatory response and STAT1 activation, recruitment and activation of macrophages, PMN, and fMLP (N-formyl-Methionyl-Leucyl-Phenylalanine)-stimulation. At 4 weeks, the CDC1551 bacillary load was significantly lower and the granulomatous response reduced compared to HN878 infection. Moreover, although inflammation was dampened in both Mtb infections at 4 weeks, the majority of the differentially expressed gene networks were similar to those seen at 3 hours.We propose that differential regulation of the inflammation-associated innate immune response and related gene expression changes seen at 3 hours determine the long term outcome of Mtb infection in rabbit lungs.

Project description:Microtubules play critical roles in regulating the activation of NLRP3 inflammasome and microtubule-destabilizing agents such as colchicine have been shown to suppress the activation of this inflammasome. However, it remains largely unknown whether paclitaxel, a microtubule-stabilizing agent being used in cancer therapy, has any influences on NLRP3 inflammasome activation. Here we showed that paclitaxel pre-treatment greatly enhanced ATP- or nigericin-induced NLRP3 inflammasome activation as indicated by increased release of cleaved caspase-1 and mature IL-1β, enhanced formation of ASC speck, and increased gasdermin D cleavage and pyroptosis. Paclitaxel time- and dose-dependently induced α-tubulin acetylation in LPS-primed murine and human macrophages and further increased ATP- or nigericin-induced α-tubulin acetylation. Such increased α-tubulin acetylation was significantly suppressed either by resveratrol or NAD+ (coenzyme required for deacetylase activity of SIRT2), or by genetic knockdown of MEC-17 (gene encoding α-tubulin acetyltransferase 1). Concurrently, the paclitaxel-mediated enhancement of NLRP3 inflammasome activation was significantly suppressed by resveratrol, NAD+, or MEC-17 knockdown, indicating the involvement of paclitaxel-induced α-tubulin acetylation in the augmentation of NLRP3 inflammasome activation. Similar to paclitaxel, epothilone B that is another microtubule-stabilizing agent also induced α-tubulin acetylation and increased NLRP3 inflammasome activation in macrophages in response to ATP treatment. Consistent with the in vitro results, intraperitoneal administration of paclitaxel significantly increased serum IL-1β levels, reduced bacterial burden, dampened infiltration of inflammatory cells in the liver, and improved animal survival in a mouse model of bacterial infection. Collectively, our data indicate that paclitaxel potentiated NLRP3 inflammasome activation by inducing α-tubulin acetylation and thereby conferred enhanced antibacterial innate responses, suggesting its potential application against pathogenic infections beyond its use as a chemotherapeutic agent.

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Dataset Information

Mycobacterium tuberculosis PE_PGRS41 Enhances the Intracellular Survival of M. smegmatis within Macrophages Via Blocking Innate Immunity and Inhibition of Host Defense.

Publications

Mycobacterium tuberculosis PE_PGRS41 Enhances the Intracellular Survival of M. smegmatis within Macrophages Via Blocking Innate Immunity and Inhibition of Host Defense.

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