C J Mabry, C G Weindel, L W Stranahan, J J VanPortfliet, J R Davis, E L Martinez, A P West, K L Patrick, R O Watson
The genetic and molecular determinants that underlie the heterogeneity of Mycobacterium tuberculosis (Mtb) infection outcomes in humans are poorly understood. Multiple lines of evidence demonstrate that mitochondrial dysfunction can exacerbate mycobacterial disease severity, and mutations in some mitochondrial genes confer susceptibility to mycobacterial infection in humans. Here, we report that mutations in mitochondria DNA (mtDNA) polymerase gamma potentiate susceptibility to Mtb infection in mice. PolgD257A mutator mtDNA mice fail to mount a protective innate immune response at an early infection time point, evidenced by high bacterial burdens, reduced M1 macrophages, and excessive neutrophil infiltration in the lungs. Immunohistochemistry reveals signs of enhanced necrosis in the lungs of Mtb-infected PolgD257A mice, and PolgD257A mutator macrophages are hypersusceptible to extrinsic triggers of necroptosis ex vivo. By assigning a role for mtDNA mutations in driving necrosis during Mtb infection, this work further highlights the requirement for mitochondrial homeostasis in mounting balanced immune responses to Mtb.
{"title":"Necrosis drives susceptibility to <i>Mycobacterium tuberculosis</i> in Polg<sup>D257A</sup> mutator mice.","authors":"C J Mabry, C G Weindel, L W Stranahan, J J VanPortfliet, J R Davis, E L Martinez, A P West, K L Patrick, R O Watson","doi":"10.1128/iai.00324-24","DOIUrl":"10.1128/iai.00324-24","url":null,"abstract":"<p><p>The genetic and molecular determinants that underlie the heterogeneity of <i>Mycobacterium tuberculosis</i> (Mtb) infection outcomes in humans are poorly understood. Multiple lines of evidence demonstrate that mitochondrial dysfunction can exacerbate mycobacterial disease severity, and mutations in some mitochondrial genes confer susceptibility to mycobacterial infection in humans. Here, we report that mutations in mitochondria DNA (mtDNA) polymerase gamma potentiate susceptibility to Mtb infection in mice. Polg<sup>D257A</sup> mutator mtDNA mice fail to mount a protective innate immune response at an early infection time point, evidenced by high bacterial burdens, reduced M1 macrophages, and excessive neutrophil infiltration in the lungs. Immunohistochemistry reveals signs of enhanced necrosis in the lungs of Mtb-infected Polg<sup>D257A</sup> mice, and Polg<sup>D257A</sup> mutator macrophages are hypersusceptible to extrinsic triggers of necroptosis <i>ex vivo</i>. By assigning a role for mtDNA mutations in driving necrosis during Mtb infection, this work further highlights the requirement for mitochondrial homeostasis in mounting balanced immune responses to Mtb.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0032424"},"PeriodicalIF":2.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143448945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shelby J Dechow, Rajni Goyal, Benjamin K Johnson, Elizabeth R Haiderer, Robert B Abramovitch
The Mycobacterium tuberculosis (Mtb) two-component regulatory system PhoPR is implicated in pH sensing within the macrophage because it is strongly induced by acidic pH both in vitro and the macrophage phagosome. The carbonic anhydrase (CA) inhibitor ethoxzolamide inhibits PhoPR signaling supporting the hypothesis that CO2 may also play a role in regulating PhoPR. Here, we show that increasing CO2 concentration induces PhoPR signaling, at both pH 7.0 and pH 5.7. At acidic pH 5.7, a normally strong inducer of PhoPR signaling, increasing CO2 from 0.5% to 5% further induces the pathway, showing CO2 acts synergistically with acidic pH to induce the PhoPR regulon. Based on these findings, we propose that PhoPR functions as a CO2 sensor. Mtb has three CA (CanA, CanB, and CanC), and using CRISPR interference knockdowns and gene deletion mutants, we assessed which CAs regulate PhoPR signaling and macrophage survival. We first examined if CA played a role in Mtb pathogenesis and observed that CanB was required for survival in macrophages, where the knockdown strain had ~1-log reduction in survival. To further define the interplay of CO2 and Mtb signaling, we conducted transcriptional profiling experiments at varying pH and CO2 concentrations. As hypothesized, we observed that the induction of PhoPR at acidic pH is dependent on CO2 concentration, with a subset of core PhoPR regulon genes dependent on both 5% CO2 and acidic pH for their induction, including expression of the ESX-1 secretion system. Transcriptional profiling also revealed core CO2-responsive genes that were differentially expressed independently of the PhoPR regulon or the acidic pH-inducible regulon. Notably, genes regulated by a second two-component regulatory system, TrcRS, are associated with adaptation to changes in CO2.
{"title":"Carbon dioxide regulates <i>Mycobacterium tuberculosis</i> PhoPR signaling and virulence.","authors":"Shelby J Dechow, Rajni Goyal, Benjamin K Johnson, Elizabeth R Haiderer, Robert B Abramovitch","doi":"10.1128/iai.00568-24","DOIUrl":"https://doi.org/10.1128/iai.00568-24","url":null,"abstract":"<p><p>The <i>Mycobacterium tuberculosis</i> (Mtb) two-component regulatory system PhoPR is implicated in pH sensing within the macrophage because it is strongly induced by acidic pH both <i>in vitro</i> and the macrophage phagosome. The carbonic anhydrase (CA) inhibitor ethoxzolamide inhibits PhoPR signaling supporting the hypothesis that CO<sub>2</sub> may also play a role in regulating PhoPR. Here, we show that increasing CO<sub>2</sub> concentration induces PhoPR signaling, at both pH 7.0 and pH 5.7. At acidic pH 5.7, a normally strong inducer of PhoPR signaling, increasing CO<sub>2</sub> from 0.5% to 5% further induces the pathway, showing CO<sub>2</sub> acts synergistically with acidic pH to induce the PhoPR regulon. Based on these findings, we propose that PhoPR functions as a CO<sub>2</sub> sensor. Mtb has three CA (CanA, CanB, and CanC), and using CRISPR interference knockdowns and gene deletion mutants, we assessed which CAs regulate PhoPR signaling and macrophage survival. We first examined if CA played a role in Mtb pathogenesis and observed that CanB was required for survival in macrophages, where the knockdown strain had ~1-log reduction in survival. To further define the interplay of CO<sub>2</sub> and Mtb signaling, we conducted transcriptional profiling experiments at varying pH and CO<sub>2</sub> concentrations. As hypothesized, we observed that the induction of PhoPR at acidic pH is dependent on CO<sub>2</sub> concentration, with a subset of core PhoPR regulon genes dependent on both 5% CO<sub>2</sub> and acidic pH for their induction, including expression of the ESX-1 secretion system. Transcriptional profiling also revealed core CO<sub>2</sub>-responsive genes that were differentially expressed independently of the PhoPR regulon or the acidic pH-inducible regulon. Notably, genes regulated by a second two-component regulatory system, TrcRS, are associated with adaptation to changes in CO<sub>2</sub>.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0056824"},"PeriodicalIF":2.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143440746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18Epub Date: 2025-01-22DOI: 10.1128/iai.00271-24
Lin Xu, Caiying Wang, Yuhuan Liu, Yanlan Zhang, Zhen Li, Lin Pang
Pertussis, a severe infectious disease in children, has become increasingly prominent in recent years. This study aims to investigate the role of the MASP1 protein in severe pertussis in children through multi-omics analysis, providing a theoretical basis for the development of novel therapeutic strategies. The study retrieved macro-genome and 16S rRNA data of pediatric pertussis from public databases to analyze microbial diversity and specific flora abundance, conducting pathway functional enrichment analysis. Differential expression analysis of transcriptome data and Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis, combined with machine learning, identified the key gene MASP1. A Bordetella pertussis infection model was established using human bronchial epithelial cell line HBE135-E6E7 to validate MASP1 expression changes and investigate its relationship with airway epithelial cell damage by constructing cell lines overexpressing and knocking down MASP1. Finally, the impact of inhibiting MASP1 expression on infection symptoms was evaluated using a mouse pertussis infection model. The results revealed significant differences in microbial diversity and specific flora abundance between healthy children and those with pertussis, with MASP1 significantly upregulated in severe pertussis and its inhibition alleviating infection symptoms. The study highlights the critical role of MASP1 in pertussis, providing a crucial foundation for developing therapeutic strategies targeting MASP1.
{"title":"MASP1 modulation as a novel therapeutic target in severe pediatric pertussis: insights from a multi-omics approach.","authors":"Lin Xu, Caiying Wang, Yuhuan Liu, Yanlan Zhang, Zhen Li, Lin Pang","doi":"10.1128/iai.00271-24","DOIUrl":"10.1128/iai.00271-24","url":null,"abstract":"<p><p>Pertussis, a severe infectious disease in children, has become increasingly prominent in recent years. This study aims to investigate the role of the MASP1 protein in severe pertussis in children through multi-omics analysis, providing a theoretical basis for the development of novel therapeutic strategies. The study retrieved macro-genome and 16S rRNA data of pediatric pertussis from public databases to analyze microbial diversity and specific flora abundance, conducting pathway functional enrichment analysis. Differential expression analysis of transcriptome data and Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analysis, combined with machine learning, identified the key gene MASP1. A <i>Bordetella pertussis</i> infection model was established using human bronchial epithelial cell line HBE135-E6E7 to validate MASP1 expression changes and investigate its relationship with airway epithelial cell damage by constructing cell lines overexpressing and knocking down MASP1. Finally, the impact of inhibiting MASP1 expression on infection symptoms was evaluated using a mouse pertussis infection model. The results revealed significant differences in microbial diversity and specific flora abundance between healthy children and those with pertussis, with MASP1 significantly upregulated in severe pertussis and its inhibition alleviating infection symptoms. The study highlights the critical role of MASP1 in pertussis, providing a crucial foundation for developing therapeutic strategies targeting MASP1.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0027124"},"PeriodicalIF":2.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11834402/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143004768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18Epub Date: 2025-01-13DOI: 10.1128/iai.00541-24
{"title":"Expression of Concern for Herrera et al., \"Protection against Malaria in <i>Aotus</i> Monkeys Immunized with a Recombinant Blood-Stage Antigen Fused to a Universal T-Cell Epitope: Correlation of Serum Gamma Interferon Levels with Protection\".","authors":"","doi":"10.1128/iai.00541-24","DOIUrl":"10.1128/iai.00541-24","url":null,"abstract":"","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0054124"},"PeriodicalIF":2.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11834460/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142970518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18Epub Date: 2024-12-20DOI: 10.1128/iai.00445-24
Emily Tamkin, Brian P Lorenz, Arianna McCarty, Sam Fulte, Elan Eisenmesser, Alexander R Horswill, Sarah E Clark
The composition of the respiratory tract microbiome is a notable predictor of infection-related morbidities and mortalities among both adults and children. Species of Corynebacterium, which are largely present as commensals in the upper airway and other body sites, are associated with lower colonization rates of opportunistic bacterial pathogens such as Streptococcus pneumoniae and Staphylococcus aureus. In this study, Corynebacterium-mediated protective effects against S. pneumoniae and S. aureus were directly compared using in vivo and in vitro models. Pre-exposure to Corynebacterium pseudodiphtheriticum reduced the ability of S. aureus and S. pneumoniae to infect the lungs of mice, indicating a broadly protective effect. Adherence of both pathogens to human respiratory tract epithelial cells was significantly impaired following pre-exposure to C. pseudodiphtheriticum or Corynebacterium accolens, and this effect was dependent on live Corynebacterium colonizing the epithelial cells. However, Corynebacterium-secreted factors had distinct effects on each pathogen. Corynebacterium lipase activity was bactericidal against S. pneumoniae, but not S. aureus. Instead, the hemolytic activity of pore-forming toxins produced by S. aureus was directly blocked by a novel Corynebacterium-secreted factor with protease activity. Taken together, these results suggest diverse mechanisms by which Corynebacterium contribute to the protective effect of the airway microbiome against opportunistic bacterial pathogens.
{"title":"Airway <i>Corynebacterium</i> interfere with <i>Streptococcus pneumoniae</i> and <i>Staphylococcus aureus</i> infection and express secreted factors selectively targeting each pathogen.","authors":"Emily Tamkin, Brian P Lorenz, Arianna McCarty, Sam Fulte, Elan Eisenmesser, Alexander R Horswill, Sarah E Clark","doi":"10.1128/iai.00445-24","DOIUrl":"10.1128/iai.00445-24","url":null,"abstract":"<p><p>The composition of the respiratory tract microbiome is a notable predictor of infection-related morbidities and mortalities among both adults and children. Species of <i>Corynebacterium,</i> which are largely present as commensals in the upper airway and other body sites, are associated with lower colonization rates of opportunistic bacterial pathogens such as <i>Streptococcus pneumoniae</i> and <i>Staphylococcus aureus</i>. In this study, <i>Corynebacterium</i>-mediated protective effects against <i>S. pneumoniae</i> and <i>S. aureus</i> were directly compared using <i>in vivo</i> and <i>in vitro</i> models. Pre-exposure to <i>Corynebacterium pseudodiphtheriticum</i> reduced the ability of <i>S. aureus</i> and <i>S. pneumoniae</i> to infect the lungs of mice, indicating a broadly protective effect. Adherence of both pathogens to human respiratory tract epithelial cells was significantly impaired following pre-exposure to C. <i>pseudodiphtheriticum</i> or <i>Corynebacterium accolens</i>, and this effect was dependent on live <i>Corynebacterium</i> colonizing the epithelial cells. However, <i>Corynebacterium</i>-secreted factors had distinct effects on each pathogen. <i>Corynebacterium</i> lipase activity was bactericidal against <i>S. pneumoniae</i>, but not <i>S. aureus</i>. Instead, the hemolytic activity of pore-forming toxins produced by <i>S. aureus</i> was directly blocked by a novel <i>Corynebacterium</i>-secreted factor with protease activity. Taken together, these results suggest diverse mechanisms by which <i>Corynebacterium</i> contribute to the protective effect of the airway microbiome against opportunistic bacterial pathogens.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0044524"},"PeriodicalIF":2.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11834435/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142869368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18Epub Date: 2025-01-22DOI: 10.1128/iai.00439-24
Karine Dufresne, Kait F Al, Heather C Craig, Charlotte E M Coleman, Katherine J Kasper, Jeremy P Burton, John K McCormick
Toxic shock syndrome toxin-1 (TSST-1) is a superantigen produced by Staphylococcus aureus and is the determinant of menstrual toxic shock syndrome (mTSS); however, the impact of TSST-1 on the vaginal environment beyond mTSS is not understood. Herein, we assessed how TSST-1 affects vaginal colonization by S. aureus, host inflammatory responses, and changes in microbial communities within the murine vagina. We demonstrated that TSST-1 induced a CD8+ T-cell-dependent inflammatory response in 24 h that correlated with S. aureus persistence within the vaginal tract. This increase was due to superantigen-dependent T-cell activation that triggered a change in microbial composition within the vaginal tract. Altogether, this study demonstrates that within the vaginal tract, TSST-1 modulates the vaginal microbiota to favor the survival of S. aureus in the absence of mTSS.IMPORTANCEToxic shock syndrome toxin-1 (TSST-1) is a superantigen toxin produced from Staphylococcus aureus that causes the menstrual form of toxic shock syndrome. This research demonstrates that TSST-1 also has a wider function within the vaginal tract than previously expected. We show that TSST-1, by activating CD8+ T cells, induces an inflammatory environment that modifies the vaginal microbiota to favor colonization by S. aureus. These are important findings as S. aureus can colonize the human vaginal tract efficiently and subsequently trigger dysbiosis within the microbial communities leading to several adverse outcomes such as decreased fertility, increased risks for sexually transmitted diseases, and issues related to pregnancy and birth.
{"title":"TSST-1 promotes colonization of <i>Staphylococcus aureus</i> within the vaginal tract by activation of CD8<sup>+</sup> T cells.","authors":"Karine Dufresne, Kait F Al, Heather C Craig, Charlotte E M Coleman, Katherine J Kasper, Jeremy P Burton, John K McCormick","doi":"10.1128/iai.00439-24","DOIUrl":"10.1128/iai.00439-24","url":null,"abstract":"<p><p>Toxic shock syndrome toxin-1 (TSST-1) is a superantigen produced by <i>Staphylococcus aureus</i> and is the determinant of menstrual toxic shock syndrome (mTSS); however, the impact of TSST-1 on the vaginal environment beyond mTSS is not understood. Herein, we assessed how TSST-1 affects vaginal colonization by <i>S. aureus</i>, host inflammatory responses, and changes in microbial communities within the murine vagina. We demonstrated that TSST-1 induced a CD8<sup>+</sup> T-cell-dependent inflammatory response in 24 h that correlated with <i>S. aureus</i> persistence within the vaginal tract. This increase was due to superantigen-dependent T-cell activation that triggered a change in microbial composition within the vaginal tract. Altogether, this study demonstrates that within the vaginal tract, TSST-1 modulates the vaginal microbiota to favor the survival of <i>S. aureus</i> in the absence of mTSS.IMPORTANCEToxic shock syndrome toxin-1 (TSST-1) is a superantigen toxin produced from <i>Staphylococcus aureus</i> that causes the menstrual form of toxic shock syndrome. This research demonstrates that TSST-1 also has a wider function within the vaginal tract than previously expected. We show that TSST-1, by activating CD8<sup>+</sup> T cells, induces an inflammatory environment that modifies the vaginal microbiota to favor colonization by <i>S. aureus</i>. These are important findings as <i>S. aureus</i> can colonize the human vaginal tract efficiently and subsequently trigger dysbiosis within the microbial communities leading to several adverse outcomes such as decreased fertility, increased risks for sexually transmitted diseases, and issues related to pregnancy and birth.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0043924"},"PeriodicalIF":2.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11834441/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143004772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18Epub Date: 2025-01-13DOI: 10.1128/iai.00542-24
{"title":"Expression of Concern for Perlaza et al., \"Immunogenicity of Four <i>Plasmodium falciparum</i> Preerythrocytic Antigens in <i>Aotus lemurinus</i> Monkeys\".","authors":"","doi":"10.1128/iai.00542-24","DOIUrl":"10.1128/iai.00542-24","url":null,"abstract":"","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0054224"},"PeriodicalIF":2.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11834533/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142970520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18Epub Date: 2025-01-13DOI: 10.1128/iai.00532-24
Camille M Riffaud-Widner, Ray E Widner, Scot P Ouellette, Elizabeth A Rucks
Chlamydia is an obligate intracellular bacterial pathogen that develops within a membrane-bound vacuole called an inclusion. Throughout its developmental cycle, Chlamydia modifies the inclusion membrane (IM) with type III secreted (T3S) membrane proteins, known as inclusion membrane proteins (Incs). Via the IM, Chlamydia manipulates the host cell to acquire lipids and nutrients necessary for its growth. One key nutrient is tryptophan (Trp). As a Trp auxotroph, Chlamydia is very sensitive to Trp starvation and, in response to low Trp levels induced by the immune response, enters a viable but nonreplicating state called persistence. To maintain viability during persistence, Chlamydia must necessarily maintain both the integrity of the IM and its ability to modify host cell responses, but how Trp starvation affects IM composition and subsequent interactions with the host cell remains poorly understood. We hypothesize that, under Trp starvation conditions, Inc expression/stability or T3S function during persistence alters IM composition but that key host-Chlamydia interactions will be preserved. To examine host-Chlamydia interactions during persistence, we examined sphingomyelin, cholesterol, and transferrin trafficking to the inclusion, as well as localization of host proteins that bind to specific Incs. We identified IM composition changes during persistence by monitoring endogenous Inc abundance at the IM. Chlamydial T3S is generally functional during persistence. Specific changes in Inc composition in the IM can be linked to Trp content of a specific Inc or effector-specific defects in chlamydial T3S. Overall, our findings reveal that critical host-Chlamydia interactions are maintained during persistence mediated by Trp starvation.
{"title":"Effect of tryptophan starvation on inclusion membrane composition and chlamydial-host interactions.","authors":"Camille M Riffaud-Widner, Ray E Widner, Scot P Ouellette, Elizabeth A Rucks","doi":"10.1128/iai.00532-24","DOIUrl":"10.1128/iai.00532-24","url":null,"abstract":"<p><p><i>Chlamydia</i> is an obligate intracellular bacterial pathogen that develops within a membrane-bound vacuole called an inclusion. Throughout its developmental cycle, <i>Chlamydia</i> modifies the inclusion membrane (IM) with type III secreted (T3S) membrane proteins, known as inclusion membrane proteins (Incs). Via the IM, <i>Chlamydia</i> manipulates the host cell to acquire lipids and nutrients necessary for its growth. One key nutrient is tryptophan (Trp). As a Trp auxotroph, <i>Chlamydia</i> is very sensitive to Trp starvation and, in response to low Trp levels induced by the immune response, enters a viable but nonreplicating state called persistence. To maintain viability during persistence, <i>Chlamydia</i> must necessarily maintain both the integrity of the IM and its ability to modify host cell responses, but how Trp starvation affects IM composition and subsequent interactions with the host cell remains poorly understood. We hypothesize that, under Trp starvation conditions, Inc expression/stability or T3S function during persistence alters IM composition but that key host-<i>Chlamydia</i> interactions will be preserved. To examine host-<i>Chlamydia</i> interactions during persistence, we examined sphingomyelin, cholesterol, and transferrin trafficking to the inclusion, as well as localization of host proteins that bind to specific Incs. We identified IM composition changes during persistence by monitoring endogenous Inc abundance at the IM. Chlamydial T3S is generally functional during persistence. Specific changes in Inc composition in the IM can be linked to Trp content of a specific Inc or effector-specific defects in chlamydial T3S. Overall, our findings reveal that critical host-<i>Chlamydia</i> interactions are maintained during persistence mediated by Trp starvation.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0053224"},"PeriodicalIF":2.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11834466/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142970516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18Epub Date: 2024-12-23DOI: 10.1128/iai.00487-24
Clara Luna Marina, Raffael J Araújo de Castro, Paula Bellozi, Ana M Cruz, Pedro Henrique Bürgel, Paul G Weightman Potter, Craig Beall, Aldo Henrique Tavares, Andreza De Bem, Alexandre Alanio, Carolina Coelho, Anamélia Lorenzetti Bocca
Dormancy is an adaptation in which cells reduce their metabolism, transcription, and translation to stay alive under stressful conditions, preserving the capacity to reactivate once the environment reverts to favorable conditions. Dormancy and reactivation of Cryptococcus neoformans (Cn) are closely linked to intracellular residency within macrophages. Our previous work showed that in vitro murine macrophages rely on the viable but not cultivable (VBNC-a dormancy phenotype) fungus from active Cn, with striking differences in immunometabolic gene expression. Here, we analyzed the influence of VBNC and active Cn on the immunometabolism of infected macrophages, combining metabolic gene expression, mitochondrial membrane potential (ΔΨm), oxygen consumption analysis, and uptake of glucose and fatty acids. The active fungus induced mitochondrial depolarization, and increased glycolysis and mitochondrial oxygen consumption. VBNC infection in bone marrow-derived macrophage (BMDM) caused an attenuated modification in mitochondrial metabolism. However, we found differences in BMDM infected with VBNC vs those infected with active fungus, where VBNC induced an increment in fatty acid uptake in M0 and M1 BMDM, measured by incorporation of BODIPY-palmitate, accompanied by an increase in expression of fatty acid transporters Fabp1 and Fabp4. Overall, distinct fatty acid-related responses induced by VBNC and active Cn suggest different immunomodulatory reactions, depending on the microbial growth stage. We posit that, for VBNC, some of these macrophage metabolic responses reflect the establishment of prolonged microbial intracellular residency and possibly initial stages of granuloma formation.
{"title":"Immunometabolic reprogramming in macrophages infected with active and dormant <i>Cryptococcus neoformans</i>: differential modulation of respiration, glycolysis, and fatty acid utilization.","authors":"Clara Luna Marina, Raffael J Araújo de Castro, Paula Bellozi, Ana M Cruz, Pedro Henrique Bürgel, Paul G Weightman Potter, Craig Beall, Aldo Henrique Tavares, Andreza De Bem, Alexandre Alanio, Carolina Coelho, Anamélia Lorenzetti Bocca","doi":"10.1128/iai.00487-24","DOIUrl":"10.1128/iai.00487-24","url":null,"abstract":"<p><p>Dormancy is an adaptation in which cells reduce their metabolism, transcription, and translation to stay alive under stressful conditions, preserving the capacity to reactivate once the environment reverts to favorable conditions. Dormancy and reactivation of <i>Cryptococcus neoformans</i> (<i>Cn</i>) are closely linked to intracellular residency within macrophages. Our previous work showed that <i>in vitro</i> murine macrophages rely on the viable but not cultivable (VBNC-a dormancy phenotype) fungus from active <i>Cn</i>, with striking differences in immunometabolic gene expression. Here, we analyzed the influence of VBNC and active <i>Cn</i> on the immunometabolism of infected macrophages, combining metabolic gene expression, mitochondrial membrane potential (ΔΨm), oxygen consumption analysis, and uptake of glucose and fatty acids. The active fungus induced mitochondrial depolarization, and increased glycolysis and mitochondrial oxygen consumption. VBNC infection in bone marrow-derived macrophage (BMDM) caused an attenuated modification in mitochondrial metabolism. However, we found differences in BMDM infected with VBNC vs those infected with active fungus, where VBNC induced an increment in fatty acid uptake in M0 and M1 BMDM, measured by incorporation of BODIPY-palmitate, accompanied by an increase in expression of fatty acid transporters <i>Fabp1</i> and <i>Fabp4</i>. Overall, distinct fatty acid-related responses induced by VBNC and active <i>Cn</i> suggest different immunomodulatory reactions, depending on the microbial growth stage. We posit that, for VBNC, some of these macrophage metabolic responses reflect the establishment of prolonged microbial intracellular residency and possibly initial stages of granuloma formation.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0048724"},"PeriodicalIF":2.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11834436/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142876923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-18Epub Date: 2025-01-13DOI: 10.1128/iai.00545-24
{"title":"Expression of Concern for Lopez-Perez et al., \"IgG Responses to the <i>Plasmodium falciparum</i> Antigen VAR2CSA in Colombia Are Restricted to Pregnancy and Are Not Induced by Exposure to <i>Plasmodium vivax</i>\".","authors":"","doi":"10.1128/iai.00545-24","DOIUrl":"10.1128/iai.00545-24","url":null,"abstract":"","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0054524"},"PeriodicalIF":2.9,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11834399/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142970519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}