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- Mohanty, Soumitra, et al.
(författare)
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A mycobacterial phosphoribosyltransferase promotes bacillary survival by inhibiting oxidative stress and autophagy pathways in macrophages and zebrafish.
- 2015
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 290:21, s. 13321-13343
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Tidskriftsartikel (refereegranskat)abstract
- Mycobacterium tuberculosis (Mtb) employs various strategies to modulate host immune responses to facilitate its persistence in macrophages. The Mtb cell wall contains numerous glycoproteins with unknown role in pathogenesis. Here, by using concavalinA and LC-MS analysis we identified a novel mannosylated glycoprotein phosphoribosyl- transferase, encoded by the Rv3242c, from Mtb cell walls. Homology modeling, bioinformatic analyses and assay of phosphoribosyltransferase activity measurement in Mycobacterium smegmatis expressing recombinant Rv3242c (MsmRv3242c) confirmed the mass spectrometry data. Using Mycobacterium marinum-zebrafish and the surrogate MsmRv3242c infection models, we proved that phosphoribosyltransferase is involved in mycobacterial virulence. Histological and infection assays showed that M. marinum mimG mutant, an Rv3242c orthologue in a pathogenic M. marinum strain, was strongly attenuated in adult zebrafish and also survived less in macrophages. In contrast, infection with wild-type and the complemented ∆mimG:Rv3242c M. marinum strains showed prominent pathological features such as severe emaciation, skin lesions, hemorrhaging, and more zebrafish death. Similarly, recombinant MsmRv3242c bacteria showed increased invasion in non-phagocytic epithelial cells and longer intracellular survival in macrophages as compared to wild-type and vector control M. smegmatis strains. Further mechanistic studies revealed that the Rv3242c and mimG mediated enhancement of intramacrophagic survival was due to inhibition of autophagy, reactive oxygen species and reduced activities of superoxide dismutase and catalase enzymes. Infection with MsmRv3242c also activated the MAPK pathway, NF-κB and inflammatory cytokines. In summary, we show that a novel mycobacterial mannosylated phosphoribosyltransferase acts as a virulence and immunomodulatory factors, suggesting that it may constitute a novel target for antimycobacterial drugs.
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| 2. |
- Jena, Prajna, et al.
(författare)
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Azurophil Granule Proteins Constitute the Major Mycobactericidal Proteins in Human Neutrophils and Enhance the Killing of Mycobacteria in Macrophages
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:12
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Tidskriftsartikel (refereegranskat)abstract
- Pathogenic mycobacteria reside in, and are in turn controlled by, macrophages. However, emerging data suggest that neutrophils also play a critical role in innate immunity to tuberculosis, presumably by their different antibacterial granule proteins. In this study, we purified neutrophil azurophil and specific granules and systematically analyzed the antimycobacterial activity of some purified azurophil and specific granule proteins against M. smegmatis, M. bovis-BCG and M. tuberculosis H37Rv. Using gel overlay and colony forming unit assays we showed that the defensin-depleted azurophil granule proteins (AZP) were more active against mycobacteria compared to other granule proteins and cytosolic proteins. The proteins showing antimycobacterial activity were identified by MALDI-TOF mass spectrometry. Electron microscopic studies demonstrate that the AZP disintegrate bacterial cell membrane resulting in killing of mycobacteria. Exogenous addition of AZP to murine macrophage RAW 264.7, THP-1 and peripheral blood monocyte-derived macrophages significantly reduced the intracellular survival of mycobacteria without exhibiting cytotoxic activity on macrophages. Immunofluorescence studies showed that macrophages actively endocytose neutrophil granular proteins. Treatment with AZP resulted in increase in co-localization of BCG containing phagosomes with lysosomes but not in increase of autophagy. These data demonstrate that neutrophil azurophil proteins may play an important role in controlling intracellular survival of mycobacteria in macrophages. Citation: Jena P, Mohanty S, Mohanty T, Kallert S, Morgelin M, et al. (2012) Azurophil Granule Proteins Constitute the Major Mycobactericidal Proteins in Human Neutrophils and Enhance the Killing of Mycobacteria in Macrophages. PLoS ONE 7(12): e50345. doi:10.1371/journal.pone.0050345
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| 3. |
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| 4. |
- Sonawane, Avinash, et al.
(författare)
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Cathelicidin is involved in the intracellular killing of mycobacteria in macrophages.
- 2011
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Ingår i: Cellular Microbiology. - : Hindawi Limited. - 1462-5814. ; 13, s. 1601-1617
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Tidskriftsartikel (refereegranskat)abstract
- Macrophages have been shown to kill Mycobacterium tuberculosis through the action of the antimicrobial peptide cathelicidin (CAMP), whose expression was shown to be induced by 1,25-dihydroxyvitamin D3 (1,25D3). Here, we investigated in detail the antimycobacterial effect of murine and human cathelicidin against Mycobacterium smegmatis and M. bovis BCG infections. We have synthesized novel LL-37 peptide variants that exhibited potent in vitro bactericidal activity against M. smegmatis, M. bovis BCG and M. tuberculosis H37Rv, as compared with parental peptide. We show that the exogenous addition of LL-37 or endogenous overexpression of cathelicidin in macrophages significantly reduced the intracellular survival of mycobacteria relative to control cells. An upregulation of cathelicidin mRNA expression was observed that correlated with known M. smegmatis killing phases in J774 macrophages. Moreover, RNAi-based Camp knock-down macrophages and Camp(-/-) bone marrow derived mouse macrophages were significantly impaired in their ability to kill mycobacteria. M. smegmatis killing in Camp(-/-) macrophages was less extensive than in Camp(+/+) cells following activation with FSL-1, an inducer of cathelicidin expression. Finally we show that LL-37 and 1,25D3 treatment results in increase in colocalization of BCG-containing phagosomes with lysosomes. Altogether, these data demonstrate that cathelicidin plays an important role in controlling intracellular survival of mycobacteria.
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