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Pneumococcal VncR Strain-Specifically Regulates Capsule Polysaccharide Synthesis

Capsular polysaccharides (CPS), a major virulence factor in Streptococcus pneumoniae, become thicker during blood invasion while not during asymptomatic nasopharyngeal colonization. However, the underlying mechanism controlling this differential pneumococcal CPS regulation remain unclear. Here, we s...

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Autores principales: Ghosh, Prachetash, Shah, Masaud, Ravichandran, Subramaniyam, Park, Sang-Sang, Iqbal, Hamid, Choi, Sangdun, Kim, Kyeong Kyu, Rhee, Dong Kwon
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6781885/
https://www.ncbi.nlm.nih.gov/pubmed/31632380
http://dx.doi.org/10.3389/fmicb.2019.02279
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author Ghosh, Prachetash
Shah, Masaud
Ravichandran, Subramaniyam
Park, Sang-Sang
Iqbal, Hamid
Choi, Sangdun
Kim, Kyeong Kyu
Rhee, Dong Kwon
author_facet Ghosh, Prachetash
Shah, Masaud
Ravichandran, Subramaniyam
Park, Sang-Sang
Iqbal, Hamid
Choi, Sangdun
Kim, Kyeong Kyu
Rhee, Dong Kwon
author_sort Ghosh, Prachetash
collection PubMed
description Capsular polysaccharides (CPS), a major virulence factor in Streptococcus pneumoniae, become thicker during blood invasion while not during asymptomatic nasopharyngeal colonization. However, the underlying mechanism controlling this differential pneumococcal CPS regulation remain unclear. Here, we show how VncR, the response regulator of the vancomycin resistance locus (vncRS operon), regulates CPS expression in vncR mutants in three serotype (type 2, 3, and 6B) backgrounds upon exposure to serum lactoferrin (LF). Comparative analysis of CPS levels in the wild type (WT) of three strains and their isogenic vncR mutants after LF exposure revealed a strain-specific alteration in CPS production. Consistently, VncR-mediated strain-specific CPS production is correlated with pneumococcal virulence, in vivo. Electrophoretic mobility-shift assay and co-immunoprecipitation revealed an interaction between VncR and the cps promoter (cpsp) in the presence of serum. In addition, in silico analysis uncovered this protein-DNA interaction, suggesting that VncR binds with the cpsp, and recognizes the strain-specific significance of the tandem repeats in cpsp. Taken together, the interaction of VncR and cpsp after serum exposure plays an essential role in regulating differential strain-specific CPS production, which subsequently determines strain-specific systemic virulence. This study highlights how host protein LF contributes to pneumococcal VncR-mediated CPS production. As CPS plays a significant role in immune evasion, these findings suggest that drugs designed to interrupt the VncR-mediated CPS production could help to combat pneumococcal infections.
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spelling pubmed-67818852019-10-18 Pneumococcal VncR Strain-Specifically Regulates Capsule Polysaccharide Synthesis Ghosh, Prachetash Shah, Masaud Ravichandran, Subramaniyam Park, Sang-Sang Iqbal, Hamid Choi, Sangdun Kim, Kyeong Kyu Rhee, Dong Kwon Front Microbiol Microbiology Capsular polysaccharides (CPS), a major virulence factor in Streptococcus pneumoniae, become thicker during blood invasion while not during asymptomatic nasopharyngeal colonization. However, the underlying mechanism controlling this differential pneumococcal CPS regulation remain unclear. Here, we show how VncR, the response regulator of the vancomycin resistance locus (vncRS operon), regulates CPS expression in vncR mutants in three serotype (type 2, 3, and 6B) backgrounds upon exposure to serum lactoferrin (LF). Comparative analysis of CPS levels in the wild type (WT) of three strains and their isogenic vncR mutants after LF exposure revealed a strain-specific alteration in CPS production. Consistently, VncR-mediated strain-specific CPS production is correlated with pneumococcal virulence, in vivo. Electrophoretic mobility-shift assay and co-immunoprecipitation revealed an interaction between VncR and the cps promoter (cpsp) in the presence of serum. In addition, in silico analysis uncovered this protein-DNA interaction, suggesting that VncR binds with the cpsp, and recognizes the strain-specific significance of the tandem repeats in cpsp. Taken together, the interaction of VncR and cpsp after serum exposure plays an essential role in regulating differential strain-specific CPS production, which subsequently determines strain-specific systemic virulence. This study highlights how host protein LF contributes to pneumococcal VncR-mediated CPS production. As CPS plays a significant role in immune evasion, these findings suggest that drugs designed to interrupt the VncR-mediated CPS production could help to combat pneumococcal infections. Frontiers Media S.A. 2019-10-01 /pmc/articles/PMC6781885/ /pubmed/31632380 http://dx.doi.org/10.3389/fmicb.2019.02279 Text en Copyright © 2019 Ghosh, Shah, Ravichandran, Park, Iqbal, Choi, Kim and Rhee. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
Ghosh, Prachetash
Shah, Masaud
Ravichandran, Subramaniyam
Park, Sang-Sang
Iqbal, Hamid
Choi, Sangdun
Kim, Kyeong Kyu
Rhee, Dong Kwon
Pneumococcal VncR Strain-Specifically Regulates Capsule Polysaccharide Synthesis
title Pneumococcal VncR Strain-Specifically Regulates Capsule Polysaccharide Synthesis
title_full Pneumococcal VncR Strain-Specifically Regulates Capsule Polysaccharide Synthesis
title_fullStr Pneumococcal VncR Strain-Specifically Regulates Capsule Polysaccharide Synthesis
title_full_unstemmed Pneumococcal VncR Strain-Specifically Regulates Capsule Polysaccharide Synthesis
title_short Pneumococcal VncR Strain-Specifically Regulates Capsule Polysaccharide Synthesis
title_sort pneumococcal vncr strain-specifically regulates capsule polysaccharide synthesis
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6781885/
https://www.ncbi.nlm.nih.gov/pubmed/31632380
http://dx.doi.org/10.3389/fmicb.2019.02279
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