Suppression of Toll-like receptor 2–mediated proinflammatory responses by <i>Mycobacterium tuberculosis</i> protein Rv3529c

Bandyopadhyay, Upasana; Chadha, Attinder; Gupta, Priya; Tiwari, Brijendra K; Bhattacharyya, Kausik; Popli, Sonam; Rajagopal, Raman; Brahamachari, Vani; Singh, Yogendra; Malhotra, Pawan; Natarajan, Krishnamurthy

doi:10.1189/jlb.4a0217-042r

Cited by 19 publications

(16 citation statements)

References 35 publications

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“…Our previous study also reported another tuberculosis protein EspR, which could bind to MyD88 and inhibit the TLR pathway activation as well as subsequent macrophage inflammation [33]. In line with our data, Bandyopadhyay U and colleagues [34] showed that Mtb protein Bone marrow derived macrophages (BMDMs) were prepared as previously described [33].…”

Section: Discussionsupporting

confidence: 80%

Mycobacteria tuberculosisPPE36 modulates host inflammation by promoting E3 ligase Smurf1-mediated MyD88 degradation

Peng

Yan

Xiong

2021

Preprint

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Mycobacterium tuberculosis (Mtb) PPE36, a cell-wall associated protein is highly specific and conserved for the Mtb complex group. Although it has been proven essential for iron utilization, little is known about the role of PPE36 in regulating host immune responses. Here we exhibited that PPE36 preferentially enriched in Mtb virulent strains, and could efficiently inhibit host inflammatory responses and increase bacterial loads both in mycobacterium-infected macrophages and mice. In exploring the underlying mechanisms, we found that PPE36 could robustly inhibit the activation of inflammatory NF-κB and MAPK (ERK, p38 and JNK) pathways by promoting E3 ligase Smurf1-mediated ubiquitination and proteasomal degradation of MyD88 protein. Our research revealed a previously unknown function of PPE36 on modulating host immune responses, and provided some clues to the development of novel tuberculosis treatment strategies based on immune regulation.Author SummaryMycobacterium tuberculosis (Mtb) has developed diverse immune evasion strategies to successfully establish infection in host. Identifying the important Mtb immune regulatory proteins and elucidating the underlying mechanisms are critical for tuberculosis control. Here we demonstrated that PPE36, a Mtb cell-wall associated protein, was predominantly enriched in virulent mycobacterial strains, and obviously inhibited inflammatory responses and facilitated bacterial survival in infected macrophages. Compared with the wild-type BCG, BCG lacking PPE36 (BCGΔPPE36) induced more inflammation, lower bacterial loads as well as the improved histopathological changes in the lungs of infected mice. We further found that PPE36 significantly reduced host MyD88 abundance, and inhibited the activation of subsequunt inflammatory NF-κB and MAPK pathways. In addition, this direct inhibition effect of PPE36 on MyD88 was mediated by the promoted E3 ligase Smurf1 ubiquitin -protesome pathway. This study identified PPE36 as a immune regulatory protein of Mtb, and showed it played an important role in the Mtb immune evasion.

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Section: Discussionsupporting

confidence: 80%

Mycobacteria tuberculosisPPE36 modulates host inflammation by promoting E3 ligase Smurf1-mediated MyD88 degradation

Peng

Yan

Xiong

2021

Preprint

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“…The ability to degrade cholesterol is a well-known virulence determinant for M. tuberculosis [58–60]. Sterol catabolism is thought to provide carbon for both growth and respiration [61], as well as providing a mechanism to manipulate the host cell’s immune response [62]. In BCG Danish, transposon insertions in many of the genes involved in cholesterol metabolism were found to be attenuating, in particular genes of the igr operon [63], which degrade the cholesterol side chain [45], and hsaC together with many of the genes of the kstR2 regulon [46].…”

Section: Discussionmentioning

confidence: 99%

Transposon libraries identify novel Mycobacterium bovis BCG genes involved in the dynamic interactions required for BCG to persist during in vivo passage in cattle

et al. 2019

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Background BCG is the most widely used vaccine of all time and remains the only licensed vaccine for use against tuberculosis in humans. BCG also protects other species such as cattle against tuberculosis, but due to its incompatibility with current tuberculin testing regimens remains unlicensed. BCG’s efficacy relates to its ability to persist in the host for weeks, months or even years after vaccination. It is unclear to what degree this ability to resist the host’s immune system is maintained by a dynamic interaction between the vaccine strain and its host as is the case for pathogenic mycobacteria. Results To investigate this question, we constructed transposon mutant libraries in both BCG Pasteur and BCG Danish strains and inoculated them into bovine lymph nodes. Cattle are well suited to such an assay, as they are naturally susceptible to tuberculosis and are one of the few animal species for which a BCG vaccination program has been proposed. After three weeks, the BCG were recovered and the input and output libraries compared to identify mutants with in vivo fitness defects. Less than 10% of the mutated genes were identified as affecting in vivo fitness, they included genes encoding known mycobacterial virulence functions such as mycobactin synthesis, sugar transport, reductive sulphate assimilation, PDIM synthesis and cholesterol metabolism. Many other attenuating genes had not previously been recognised as having a virulence phenotype. To test these genes, we generated and characterised three knockout mutants that were predicted by transposon mutagenesis to be attenuating in vivo: pyruvate carboxylase, a hypothetical protein (BCG_1063), and a putative cyclopropane-fatty-acyl-phospholipid synthase. The knockout strains survived as well as wild type during in vitro culture and in bovine macrophages, yet demonstrated marked attenuation during passage in bovine lymph nodes confirming that they were indeed involved in persistence of BCG in the host. Conclusion These data show that BCG is far from passive during its interaction with the host, rather it continues to employ its remaining virulence factors, to interact with the host’s innate immune system to allow it to persist, a property that is important for its protective efficacy. Electronic supplementary material The online version of this article (10.1186/s12864-019-5791-1) contains supplementary material, which is available to authorized users.

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“…MprA and MprA* were biotinylated with NHS-Biotin and subsequently conjugated with streptavidin-phycoerythrin (Strep-PE) (Chadha et al, 2015;Mehto et al, 2015;Bandyopadhyay et al, 2017). PMA-treated THP-1 cells were incubated with 15 μ g/ml of biotin-streptavidinphycoerythrin (PE) conjugated MprA and MprA*followed by dialysis to get rid of unbound biotin-streptavidin-phycoerythrin (PE) conjugate.…”

Section: Uptake and Intra-cellular Detection Of Mpra And Mpra*mentioning

confidence: 99%

“…It is well established that increased calcium concentration in infected cells promote this fusion and M.tuberculosis down modulates calcium levels upon infection (Malik et al, 2000;Malik et al, 2003). We recently showed that M.tuberculosis protein Rv3529c inhibits the fusion of phagosomes with lysosomes that is promoted by increased influx of calcium mediated by the calcium ionophore, ionomycin (Bandyopadhyay et al, 2017). We therefore, used the same strategy to investigate the role of MprA and MprA* in modulating phago-lysosome fusion.…”

Section: Mpra Promotes Macrophage Survivalmentioning

confidence: 99%

Modulation of macrophage defense responses by Mycobacterial persistence protein MprA (Rv0981) in human THP-1 cells: effect of single amino acid variation on host-pathogen interactions

Bhattacharyya

Bandopadhyay

Singh

et al. 2020

Preprint

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M. tuberculosis is one of the most successful human pathogens causing tuberculosis that leads to highest daily morbidity worldwide. The evasion of the host immune responses is an important strategy that M. tuberculosis adopts. MprA (Rv0981), the response regulator of two component system is known for DNA binding activity in the pathogen and its role in persistent infection in the host. MprA is recognized as a late stage antigen during infection. A variant form of the protein MprA with G70S polymorphism (MprA*) is observed in one of our local and in several global clinical isolates of M. tuberculosis. Here we report the nuclear localization of MprA and MprA* in differentiated macrophages. MprA and MprA* increase the expression of TGF-β and IL-10, the immune suppressive cytokines in THP-1 derived macrophage cells. Concurrently the phago-lysosome fusion is significantly reduced as shown by infection with M.bovis BCG. We show that single nucleotide variation in clinical isolates lead to quantitative variations resulting in host immune suppression and support the survival and persistence of the pathogen.

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Suppression of Toll-like receptor 2–mediated proinflammatory responses by Mycobacterium tuberculosis protein Rv3529c

Cited by 19 publications

References 35 publications

Mycobacteria tuberculosisPPE36 modulates host inflammation by promoting E3 ligase Smurf1-mediated MyD88 degradation

Mycobacteria tuberculosisPPE36 modulates host inflammation by promoting E3 ligase Smurf1-mediated MyD88 degradation

Transposon libraries identify novel Mycobacterium bovis BCG genes involved in the dynamic interactions required for BCG to persist during in vivo passage in cattle

Modulation of macrophage defense responses by Mycobacterial persistence protein MprA (Rv0981) in human THP-1 cells: effect of single amino acid variation on host-pathogen interactions

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