scholarly journals Mycobacterium tuberculosis Rv0927c Inhibits NF-κB Pathway by Downregulating the Phosphorylation Level of IκBα and Enhances Mycobacterial Survival

2021 ◽  
Vol 12 ◽  
Author(s):  
Aihong Xia ◽  
Xin Li ◽  
Juanjuan Quan ◽  
Xiang Chen ◽  
Zhengzhong Xu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Smegmatis ◽  
Bacterial Metabolism ◽  
Host Defenses ◽  
Multiple Strategies ◽  
Phosphorylation Level ◽  
Tnf Α ◽  
Short Chain Dehydrogenase

Through long-term coevolution with its host, Mycobacterium tuberculosis (M. tuberculosis) uses multiple strategies to escape host defenses. The M. tuberculosis Rv0927c protein is predicted to be a short-chain dehydrogenase/reductase related to bacterial metabolism. However, the role of Rv0927c during M. tuberculosis infection remains unclear. Here, we observed that Rv0927c inhibited the expression of IL-6, TNF-α, and IL-1β, an effect dependent on NF-κB and p38 pathways. Western blot analysis of macrophages infected with recombinant Mycobacterium smegmatis strains showed that Rv0927c attenuated NF-κB activation by downregulating the phosphorylation of IκBα. Additionally, Rv0927c enhanced intracellular survival of M. smegmatis and pathological effects in mice. In conclusion, our findings demonstrate that Rv0927c functions as a regulator of inflammatory genes and enhances the survival of M. smegmatis.

scholarly journals Mycobacterium tuberculosis Small RNA MTS1338 Confers Pathogenic Properties to Non-Pathogenic Mycobacterium smegmatis

2021 ◽  
Vol 9 (2) ◽  
pp. 414
Author(s):  
Oksana Bychenko ◽  
Yulia Skvortsova ◽  
Rustam Ziganshin ◽  
Artem Grigorov ◽  
Leonid Aseev ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Small Rna ◽  
Mycobacterium Smegmatis ◽  
Raw 264.7 Macrophages ◽  
Pathogenic Mycobacterium ◽  
Tnf Α ◽  
Non Coding Rnas ◽  
And Control ◽  
Wall Components

Small non-coding RNAs play a key role in bacterial adaptation to various stresses. Mycobacterium tuberculosis small RNA MTS1338 is upregulated during mycobacteria infection of macrophages, suggesting its involvement in the interaction of the pathogen with the host. In this study, we explored the functional effects of MTS1338 by expressing it in non-pathogenic Mycobacterium smegmatis that lacks the MTS1338 gene. The results indicated that MTS1338 slowed the growth of the recombinant mycobacteria in culture and increased their survival in RAW 264.7 macrophages, where the MTS1338-expressing strain significantly (p < 0.05) reduced the number of mature phagolysosomes and changed the production of cytokines IL-1β, IL-6, IL-10, IL-12, TGF-β, and TNF-α compared to those of the control strain. Proteomic and secretomic profiling of recombinant and control strains revealed differential expression of proteins involved in the synthesis of main cell wall components and in the regulation of iron metabolism (ESX-3 secretion system) and response to hypoxia (furA, whiB4, phoP). These effects of MTS1338 expression are characteristic for M. tuberculosis during infection, suggesting that in pathogenic mycobacteria MTS1338 plays the role of a virulence factor supporting the residence of M. tuberculosis in the host.

scholarly journals Expression of Mycobacterium smegmatisPyrazinamidase in Mycobacterium tuberculosis Confers Hypersensitivity to Pyrazinamide and Related Amides

2000 ◽  
Vol 182 (19) ◽  
pp. 5479-5485 ◽  
Author(s):  
Helena I. M. Boshoff ◽  
Valerie Mizrahi
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Smegmatis ◽  
Intracellular Localization ◽  
Wild Type ◽  
Gene Encoding ◽  
Allelic Exchange ◽  
Mutant Strains ◽  
Established Role ◽  
Amidase Gene

ABSTRACT A pyrazinamidase (PZase)-deficient pncA mutant ofMycobacterium tuberculosis, constructed by allelic exchange, was used to investigate the effects of heterologous amidase gene expression on the susceptibility of this organism to pyrazinamide (PZA) and related amides. The mutant was highly resistant to PZA (MIC, >2,000 μg/ml), in accordance with the well-established role ofpncA in the PZA susceptibility of M. tuberculosis (A. Scorpio and Y. Zhang, Nat. Med. 2:662–667, 1996). Integration of the pzaA gene encoding the major PZase/nicotinamidase from Mycobacterium smegmatis (H. I. M. Boshoff and V. Mizrahi, J. Bacteriol. 180:5809–5814, 1998) or the M. tuberculosis pncA gene into the pncAmutant complemented its PZase/nicotinamidase defect. In bothpzaA- and pncA-complemented mutant strains, the PZase activity was detected exclusively in the cytoplasm, suggesting an intracellular localization for PzaA and PncA. ThepzaA-complemented strain was hypersensitive to PZA (MIC, ≤10 μg/ml) and nicotinamide (MIC, ≥20 μg/ml) and was also sensitive to benzamide (MIC, 20 μg/ml), unlike the wild-type andpncA-complemented mutant strains, which were highly resistant to this amide (MIC, >500 μg/ml). This finding was consistent with the observation that benzamide is hydrolyzed by PzaA but not by PncA. Overexpression of PzaA also conferred sensitivity to PZA, nicotinamide, and benzamide on M. smegmatis (MIC, 150 μg/ml in all cases) and rendered Escherichia colihypersensitive for growth at low pH.

scholarly journals Hypoxanthine-Guanine Phosphoribosyltransferase Is Dispensable for Mycobacterium smegmatis Viability

2019 ◽  
Vol 202 (5) ◽  
Author(s):  
Zdeněk Knejzlík ◽  
Klára Herkommerová ◽  
Dana Hocková ◽  
Iva Pichová
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Smegmatis ◽  
Model Organism ◽  
Specific Inhibitor ◽  
Purine Salvage ◽  
Content Type ◽  
Acyclic Nucleoside Phosphonates ◽  
Hypoxanthine Guanine Phosphoribosyltransferase

ABSTRACT Purine metabolism plays a ubiquitous role in the physiology of Mycobacterium tuberculosis and other mycobacteria. The purine salvage enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is essential for M. tuberculosis growth in vitro; however, its precise role in M. tuberculosis physiology is unclear. Membrane-permeable prodrugs of specifically designed HGPRT inhibitors arrest the growth of M. tuberculosis and represent potential new antituberculosis compounds. Here, we investigated the purine salvage pathway in the model organism Mycobacterium smegmatis. Using genomic deletion analysis, we confirmed that HGPRT is the only guanine and hypoxanthine salvage enzyme in M. smegmatis but is not required for in vitro growth of this mycobacterium or survival under long-term stationary-phase conditions. We also found that prodrugs of M. tuberculosis HGPRT inhibitors displayed an unexpected antimicrobial activity against M. smegmatis that is independent of HGPRT. Our data point to a different mode of mechanism of action for these inhibitors than was originally proposed. IMPORTANCE Purine bases, released by the hydrolytic and phosphorolytic degradation of nucleic acids and nucleotides, can be salvaged and recycled. The hypoxanthine-guanine phosphoribosyltransferase (HGPRT), which catalyzes the formation of guanosine-5′-monophosphate from guanine and inosine-5′-monophosphate from hypoxanthine, represents a potential target for specific inhibitor development. Deletion of the HGPRT gene (Δhgprt) in the model organism Mycobacterium smegmatis confirmed that this enzyme is not essential for M. smegmatis growth. Prodrugs of acyclic nucleoside phosphonates (ANPs), originally designed against HGPRT from Mycobacterium tuberculosis, displayed anti-M. smegmatis activities comparable to those obtained for M. tuberculosis but also inhibited the Δhgprt M. smegmatis strain. These results confirmed that ANPs act in M. smegmatis by a mechanism independent of HGPRT.

Rv2223c, an acid inducible carboxyl-esterase of Mycobacterium tuberculosis enhanced the growth and survival of Mycobacterium smegmatis

2019 ◽  
Vol 14 (16) ◽  
pp. 1397-1415
Author(s):  
Pratibha Maan ◽  
Jagdeep Kaur
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Smegmatis ◽  
Intracellular Survival ◽  
Growth And Survival ◽  
Enhanced Expression ◽  
Stress Environment ◽  
In Vitro Stress ◽  
Carboxyl Esterase

Aim: To elucidate the role of Rv2223c in Mycobacterium tuberculosis. Methods: Purified recombinant Rv2223c protein was characterized. Expression of rv2223c in the presence of different stress environment and subcellular localization were performed in M. tuberculosis H37Ra and Mycobacterium smegmatis ( MS_2223c). Effect of its overexpression on growth rate, infection and intracellular survival in THP-1/PBMC cells were studied. Results: rRv2223c demonstrated esterase activity with preference for pNP-octanoate and hydrolyzed trioctanoate to di- and mono-octanoate. Expression of rv2223c was upregulated in acidic and nutritive stress conditions. rRv2223c was identified in extracellular and cell wall fractions. MS_2223c exhibited enhanced growth, survival during in vitro stress, infection and intracellular survival. Conclusions: Rv2223c is a secretary, carboxyl-esterase, with enhanced expression under acidic and nutritive stress condition and might help in intracellular survival of bacteria.

scholarly journals IL-27 Modulates Chemokine Production in TNF-α -Stimulated Human Oral Epithelial Cells

2017 ◽  
Vol 43 (3) ◽  
pp. 1198-1206 ◽  
Author(s):  
Yoshitaka Hosokawa ◽  
Ikuko Hosokawa ◽  
Kazumi Ozaki ◽  
Takashi Matsuo
Keyword(s):  
Signal Transduction ◽  
Epithelial Cells ◽  
Inhibitory Effect ◽  
Chemokine Production ◽  
Oral Epithelial Cells ◽  
Phosphorylation Level ◽  
Stat3 Phosphorylation ◽  
Tnf Α ◽  
Oral Epithelial

Background/Aims: Interleukin-27 (IL-27) is a cytokine which belongs to the IL-12 family. However, the role of IL-27 in the pathogenesis of periodontal disease is uncertain. The aim of this study was to examine the effect of IL-27 on chemokine production in TNF-α-stimulated human oral epithelial cells (TR146). Methods: We measured chemokine production in TR146 by ELISA. We used western blot analysis to detect the phosphorylation levels of signal transduction molecules, including STAT1 and STAT3 in TR146. We used inhibitors to examine the role of STAT1 and STAT3 activation. Results: IL-27 increased CXCR3 ligands production in TNF-α-stimulated TR146. Meanwhile, IL-27 suppressed IL-8 and CCL20 production induced by TNF-α. STAT1 phosphorylation level in IL-27 and TNF-α-stimulated TR146 was enhanced in comparison to TNF-α-stimulated TR146. STAT3 phosphorylation level in IL-27-treated TR146 did not change by TNF-α. Both STAT1 inhibitor and STAT3 inhibitor decreased CXCR3 ligands production. STAT1 inhibitor overrode the inhibitory effect of IL-27 on IL-8 and CCL20 production in TNF-α-stimulated TR146. Meanwhile, STAT3 inhibitor did not modulate IL-8 and CCL20 production. Conclusion: IL-27 might control leukocyte migration in periodontal lesion by modulating chemokine production from epithelial cells.

scholarly journals Mutations in theembC-embAIntergenic Region Contribute to Mycobacterium tuberculosis Resistance to Ethambutol

2014 ◽  
Vol 58 (11) ◽  
pp. 6837-6843 ◽  
Author(s):  
Zhenling Cui ◽  
Yuanyuan Li ◽  
Song Cheng ◽  
Hua Yang ◽  
Junmei Lu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Smegmatis ◽  
Transcriptional Activity ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Mobility Shift ◽  
Content Type ◽  
Clinical Strains ◽  
Gel Mobility Shift

ABSTRACTThe rapid increase inMycobacterium tuberculosisresistance to ethambutol (EMB) threatens the diagnosis and treatment of tuberculosis (TB). We investigated the role of mutations in theembC-embAintergenic region (IGR) in EMB-resistant clinical strains from east China. A total of 767M. tuberculosisclinical strains were collected and analyzed for their drug susceptibility to EMB using the MGIT 960 system and MIC assay, and theembC-embAIGRs of these strains were sequenced. The transcriptional activity of theembC-embAIGR mutations was examined by reporter gene assays in recombinantMycobacterium smegmatisstrains, and the effect of IGR mutations on its binding to EmbR, a transcription regulator ofembAB, was analyzed by gel mobility shift assays. Correlation coefficient analysis showed that theembC-embAIGR mutation is associated with EMB resistance. The clinical strains carrying IGR mutations had a much higher level ofembAandembBmRNA as well as higher MICs to EMB. IGR mutations had higher transcriptional activity when transformed intoM. smegmatisstrains. Mutated IGRs bound to EmbR with much higher affinity than wild-type fragments. The sensitivity of molecular drug susceptibility testing (DST) with IGR mutations as an additional marker increased from 65.5% to 73.5%. Mutations of theembC-embAIGR enhance the binding of EmbR to the promoter region ofembABand increase the expression ofembAB, thus contributing to EMB resistance. Therefore, identification of IGR mutations as markers of EMB resistance could increase the sensitivity of molecular DST.

scholarly journals Prophage Gene Rv2650c Enhances Intracellular Survival of Mycobacterium smegmatis

2022 ◽  
Vol 12 ◽  
Author(s):  
Xiangyu Fan ◽  
Zichen Liu ◽  
Zhibin Wan ◽  
Hanlu Zou ◽  
Mengzhi Ji ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mycobacterium Tuberculosis ◽  
Virulence Factors ◽  
Mycobacterium Smegmatis ◽  
Intracellular Survival ◽  
Inflammatory Factors ◽  
Bacterial Pathogenicity ◽  
Tnf Α ◽  
The World ◽  
And Control

BackgroundInduced by the pathogen Mycobacterium tuberculosis, tuberculosis remains one of the most dangerous infectious diseases in the world. As a special virus, prophage is domesticated by its host and are major contributors to virulence factors for bacterial pathogenicity. The function of prophages and their genes in M. tuberculosis is still unknown.MethodsRv2650c is a prophage gene in M. tuberculosis genome. We constructed recombinant Mycobacterium smegmatis (M. smegmatis) to observe bacteria morphology and analyze the resistance to various adverse environments. Recombinant and control strains were used to infect macrophages, respectively. Furthermore, we performed ELISA experiments of infected macrophages.ResultsRv2650c affected the spread of colonies of M. smegmatis and enhanced the resistance of M. smegmatis to macrophages and various stress agents such as acid, oxidative stress, and surfactant. ELISA experiments revealed that the Rv2650c can inhibit the expression of inflammatory factors TNF-α, IL-10, IL-1β, and IL-6.ConclusionThis study demonstrates that the prophage gene Rv2650c can inhibit the spread of colonies and the expression of inflammatory factors and promote intracellular survival of M. smegmatis. These results build the foundation for the discovery of virulence factors of M. tuberculosis, and provide novel insights into the function of the prophage in Mycobacterium.

scholarly journals Renoprotective role of bariatric surgery in patients with established CKD

2020 ◽  
Author(s):  
Enrique Morales ◽  
Esteban Porrini ◽  
Marina Martin-Taboada ◽  
Sergio Luis Lima ◽  
Rocío Vila-Bedmar ◽  
...  
Keyword(s):  
Bariatric Surgery ◽  
Renal Function ◽  
Glomerular Hyperfiltration ◽  
Effective Measure ◽  
Inflammatory Parameters ◽  
Tnf Α ◽  
Effective Option ◽  
Obese Subjects

Abstract Background Bariatric surgery (BS) has been postulated as the most effective measure for weight reduction. Weight loss improves metabolic parameters and exerts changes in renal function that lead to the amelioration of absolute or relative glomerular hyperfiltration, a condition that may renoprotective in the long term. However, few studies have demonstrated the influence of bariatric surgery in patients with severe obesity and chronic kidney disease (CKD). Our objective was to analyze the evolution of renal function, adipose tissue-derived molecules and inflammatory parameters in patients with CKD after BS. Methods This is an observational and prospective study. Thirty patients were screened and 12 were included between January 2016 to January 2018 with a 24-month follow-up. Glomerular filtration rate (GFR) was determined by plasma iohexol clearance. Adipokines, cytokines, circulating hormones and fibrotic parameters were evaluated before and 12 months after bariatric surgery using the Bioplex system. Results The mean age was 50.6 years and 58.3% were males. Seven patients had a BMI&gt; 40 kg/m2 and 66.7% were diabetic. Twenty-four months following bariatric surgery there was a significant decrease in body weight (36.4%). Proteinuria decreased by 63.7 ± 28.2%. Measured GFR significantly diminished from before surgery to month 24 after surgery (94 ± 44 to 79 ± 44 ml/min, p 0.03). There was a significant decrease in adipocyte-derived molecules (leptin, vifastin) as well as in pro-inflammatory cytokines (IL1-β, TNF-α, IL-6, MCP-1) and other circulating factors (VEGF and TGFß isoforms). Conclusions BS is an effective option to prevent kidney damage in obese subjects with CKD due to the improvement of glomerular hyperfiltration, adipocyte cytokines metabolic and inflammatory parameters.

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