Inactivation of Transcriptional Regulator FabT Influences Colony Phase Variation of Streptococcus pneumoniae

Zhang, Jinghui; Ye, Weijie; Wu, Kaifeng; Xiao, Shengnan; Zheng, Yan; Shu, Zhaoche; Yin, Yibing; Xue-mei, Zhang

doi:10.1128/mbio.01304-21

Cited by 10 publications

(10 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this study, we found that the knockout of hsdS A in the S. pneumoniae D39 strain caused an obvious change in colony phase and an unexpected decrease in capsule production. These results were in agreement with previous studies of the transcriptional repressor FabT mutation ( 41 ). Importantly, the knockout of hsdS A did not affect S. pneumoniae growth but increased mRNA expression of PGN synthesis-related genes, followed by an elevated PGN level and cell wall thickness.…”

Section: Discussionsupporting

confidence: 94%

hsdS _A regulated extracellular vesicle-associated PLY to protect Streptococcus pneumoniae from macrophage killing via LAPosomes

Wang,

Liu,

et al. 2024

Microbiol Spectr

View full text Add to dashboard Cite

Streptococcus pneumoniae is a notorious human opportunistic pathogen which undergoes a spontaneous and reversible phenotypic change in response to the host environment. We demonstrated that the regulatory gene hsdS A of DNA methylation in the type I restriction modification system altered colony transparency and substantially contributed to S. pneumoniae virulence. Most importantly, hsdS A regulated the production of extracellular vesicles (EVs) which package cytosolic, surface, and secreted proteins, including pneumolysin (PLY). Interestingly, we confirmed that EV-associated PLY utilized internalization into macrophages to prolong the survival of intracellular bacteria as a major immune evasion strategy; that is, EV-associated PLY produced by the D39 strain (EVs-D39) could induce the formation of LC3-associated monolayer vacuoles [LC3-associated phagocytosis (LAP)] and co-localize with the NADPH oxidase 2 (NOX2) complex but not ULK1 when macrophages were infected with the D39Δ ply strain. In addition, EV-associated PLY derived from the EVs-D39 promoted macrophages to release more reactive oxygen species (ROS) and expression of p-p70s6k than EV-associated PLY derived from the D39Δ hsdS A strain (EVs-D39Δ hsdS A ), whereas the expression of p-ULK1 was reversed, indicating that EVs-D39Δ hsdS A was more likely to induce conventional xenophagy. Furthermore, we identified the β1 integrin receptor as a crucial inducer of ROS to mediate LAP activation. Bacterial evasion of host clearance is closely related to insufficient acidification after the fusion of autophagosomes or LAPosomes with lysosomes. Of note, we found EV-associated PLY damaged the integrity of the lysosome membrane and changed the pH gradient, resulting in lysosomes being unable to remove intracellular bacteria and ultimately prolonging the survival of S. pneumoniae in macrophages. Finally, the extracted mouse alveolar macrophages and mouse intranasal infection models were employed to further verify the above findings. IMPORTANCE S. pneumoniae is a major human pathogen that undergoes a spontaneous and reversible phase variation that allows it to survive in different host environments. Interestingly, we found hsdS A , a gene that manipulated the phase variation, promoted the survival and replication of S. pneumoniae in macrophages by regulating EV production and EV-associated PLY. More importantly, here we provided the first evidence that higher EV-associated PLY (produced by D39) could form LAPosomes that were single membrane compartments containing S. pneumoniae , which are induced by integrin β1/NOX2/ROS pathway. At the same time, EV-associated PLY increased the permeability of lysosome membrane and induced an insufficient acidification to escape the host killing, and ultimately prolonged the survival of S. pneumoniae in macrophages. In contrast, lower EV-associated PLY (produced by D39Δ hsdS A ) activated ULK1 recruitment to form double-layered autophagosomes to eliminate bacteria.

show abstract

Section: Discussionsupporting

confidence: 94%

hsdS _A regulated extracellular vesicle-associated PLY to protect Streptococcus pneumoniae from macrophage killing via LAPosomes

Wang,

Liu,

et al. 2024

Microbiol Spectr

View full text Add to dashboard Cite

show abstract

“…This also supports our relatively quiescent EF3030 infection state from the host perspective as riboflavin genes are not as expressed (Figure 4). It has also been determined that deactivation of fatty acid biosynthesis results in a colony phase variation (33) and can also affect quorum sensing (34). It is quite possible that this allows EF3030 to leave its colonization state during pH1N1 coinfection and help turn invasive.…”

Section: Discussionmentioning

confidence: 99%

Influenza A virus modulation ofStreptococcus pneumoniaeinfection using ex vivo transcriptomics in a human primary lung epithelial cell model reveals differential host glycoconjugate uptake and metabolism

D’Mello

Lane

Tipper

et al. 2023

Preprint

View full text Add to dashboard Cite

Background: Streptococcus pneumoniae (Spn) is typically an asymptomatic colonizer of the nasopharynx but it also causes pneumonia and disseminated disease affecting various host anatomical sites. Transition from colonization to invasive disease is not well understood. Studies have shown that such a transition can occur as result of influenza A virus coinfection. Methods: We investigated the pneumococcal (serotype 19F, strain EF3030) and host transcriptomes with and without influenza A virus (A/California/07 2009 pH1N1) infection at this transition. This was done using primary, differentiated Human Bronchial Epithelial Cells (nHBEC) in a transwell monolayer model at an Air-Liquid Interface (ALI), with multispecies deep RNA-seq. Results: Distinct pneumococcal gene expression profiles were observed in the presence and absence of influenza. Influenza coinfection allowed for significantly greater pneumococcal growth and triggered the differential expression of bacterial genes corresponding to multiple metabolic pathways; in totality suggesting a fundamentally altered bacterial metabolic state and greater nutrient availability when coinfecting with influenza. Surprisingly, nHBEC transcriptomes were only modestly perturbed by infection with EF3030 alone in comparison to that resulting from Influenza A infection or coinfection, which had drastic alterations in thousands of genes. Influenza infected host transcriptomes suggest significant loss of ciliary function in host nHBEC cells. Conclusions: Influenza A virus infection of nHBEC promotes pneumococcal infection. One reason for this is an altered metabolic state by the bacterium, presumably due to host components made available as result of viral infection. Influenza infection had a far greater impact on the host response than did bacterial infection alone, and this included down regulation of genes involved in expressing cilia. We conclude that influenza infection promotes a pneumococcal metabolic shift allowing for transition from colonization to disseminated disease.

show abstract

“…Maintaining cytoplasmic membrane integrity is critical for bacterial survival and adaptation to stress conditions, and bacterial response to different environmental conditions involves adjusting its lipid composition [27]. Changes in membrane lipid composition result in alterations in its biophysical properties, and a correct FA profile is essential for membrane homeostasis [20] reviewed by [15].…”

Section: Discussionmentioning

confidence: 99%

“…Transcriptional regulation of the FAS-II cluster is under the control of FabT, a transcriptional repressor that binds both promoters of the cluster, regulating its own transcription and the expression of all of fab genes, except fabM [13, 16]. A putative FabT binding site was also reported upstream of fabM [30] and recent works have shown a FabT-dependent regulation of fabM [27, 31]. Since FabT affinity for DNA is increased by binding to long chain acyl-ACPs [16], fabM repression was proposed to rely on the formation of highly repressive FabT complexes formed with longer acyl-ACPs, which were present in the conditions tested by the authors [31].…”

Section: Discussionmentioning

confidence: 99%

RNase R Controls Membrane Fatty Acid Composition inStreptococcus pneumoniae

Alipio

Bárria

Pobre

et al. 2023

Preprint

View full text Add to dashboard Cite

Previous studies on RNase R have highlighted significant effects of this ribonuclease in several processes ofStreptococcus pneumoniaebiology. In this work we have studied the global impact of RNase R by comparing the transcriptional landscape of a deleted RNase R mutant to that of the wild-type strain, and this led us investigate specific targets affected by RNase R. RNA-Seq showed that RNase R deletion affects transcripts from several different biological processes. Of particular interest, elimination of RNase R results in overexpression of most of the genes encoding the components of type II fatty acid biosynthesis (FAS-II) cluster. We demonstrate that RNase R governs the turnover of most of genes from this pathway, affecting the outcome of the whole FAS-II cluster, and leading to an unbalanced membrane fatty acid composition. Our results show that the membrane of the deleted strain contains a higher proportion of unsaturated and long-chained fatty acids than the wild type strain. This leads to a higher fluidity of the Δrnrmutant membrane, which is probably related with the increased sensitivity to detergent observed in this strain. We demonstrate that RNase R expression is induced in cells challenged with H2O2, which is suggestive of a role for this ribonuclease on the regulation of membrane homeostasis under oxidative stress. Reprogramming of membrane fluidity is an adaptative cell response crucial for bacterial survival in constantly changing environmental conditions. The fact that RNase R controls the expression of several essential genes to the fatty acid synthesis unveils a new important function of this enzyme.

show abstract

Inactivation of Transcriptional Regulator FabT Influences Colony Phase Variation of Streptococcus pneumoniae

Cited by 10 publications

References 54 publications

hsdS _A regulated extracellular vesicle-associated PLY to protect Streptococcus pneumoniae from macrophage killing via LAPosomes

hsdS _A regulated extracellular vesicle-associated PLY to protect Streptococcus pneumoniae from macrophage killing via LAPosomes

Influenza A virus modulation ofStreptococcus pneumoniaeinfection using ex vivo transcriptomics in a human primary lung epithelial cell model reveals differential host glycoconjugate uptake and metabolism

RNase R Controls Membrane Fatty Acid Composition inStreptococcus pneumoniae

Contact Info

Product

Resources

About

Inactivation of Transcriptional Regulator FabT Influences Colony Phase Variation of Streptococcus pneumoniae

Cited by 10 publications

References 54 publications

hsdS A regulated extracellular vesicle-associated PLY to protect Streptococcus pneumoniae from macrophage killing via LAPosomes

hsdS A regulated extracellular vesicle-associated PLY to protect Streptococcus pneumoniae from macrophage killing via LAPosomes

Influenza A virus modulation ofStreptococcus pneumoniaeinfection using ex vivo transcriptomics in a human primary lung epithelial cell model reveals differential host glycoconjugate uptake and metabolism

RNase R Controls Membrane Fatty Acid Composition inStreptococcus pneumoniae

Contact Info

Product

Resources

About

hsdS _A regulated extracellular vesicle-associated PLY to protect Streptococcus pneumoniae from macrophage killing via LAPosomes

hsdS _A regulated extracellular vesicle-associated PLY to protect Streptococcus pneumoniae from macrophage killing via LAPosomes