Infection and Immunity最新文献

{"title":"Establishment of CD1b-restricted immunity to lipid antigens in the pulmonary response to <i>Mycobacterium tuberculosis</i> infection.","authors":"Macallister C Harris, Hadley E Gary, Sarah K Cooper, David F Ackart, James E DiLisio, Randall J Basaraba, Tan-Yun Cheng, Ildiko van Rhijn, D Branch Moody, Brendan K Podell","doi":"10.1128/iai.00380-24","DOIUrl":"10.1128/iai.00380-24","url":null,"abstract":"<p><p>CD1 is an antigen-presenting glycoprotein homologous to MHC I; however, CD1 proteins present lipid rather than peptide antigens. CD1 proteins are well established to present lipid antigens of <i>Mycobacterium tuberculosis</i> (Mtb) to T cells, but understanding the role of CD1-restricted immunity <i>in vivo</i> in response to Mtb infection has been limited by the availability of animal models naturally expressing the CD1 proteins implicated in human response: CD1a, CD1b, and CD1c. Guinea pigs, in contrast to other rodent models, express four CD1b orthologs, and here we utilize the guinea pig to establish the kinetics of gene and protein expression of CD1b orthologs, as well as the Mtb lipid-antigen and CD1b-restricted immune response at the tissue level over the course of Mtb infection. Our results indicate transient upregulation of CD1b expression during the effector phase of adaptive immunity that wanes with disease chronicity. Gene expression indicates that the upregulation of CD1b is the result of transcriptional induction across all CD1b orthologs. We show high CD1b3 expression on B cells, and identify CD1b3 as the predominant CD1b ortholog in pulmonary granuloma lesions. We identify <i>ex vivo</i> cytotoxic activity directed against CD1b that parallels the kinetic changes in CD1b expression in Mtb-infected lungs and spleen. This study confirms that CD1b expression is modulated by Mtb infection in lung and spleen, leading to pulmonary and extrapulmonary CD1b-restricted immunity as a component of the antigen-specific response to Mtb infection.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0038024"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11629625/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142568336","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}

{"title":"Gene expression profiling reveals host defense strategies for restricting <i>Candida albicans</i> invasion and gastritis to the limiting ridge of the murine stomach.","authors":"Karen D Zeise, Nicole R Falkowski, Joseph D Metcalf, Christopher A Brown, Gary B Huffnagle","doi":"10.1128/iai.00438-24","DOIUrl":"10.1128/iai.00438-24","url":null,"abstract":"<p><p><i>Candida albicans</i> is a fungal constituent of the human gastrointestinal microbiota that can tolerate acidic environments like the stomach, where it can be associated with ulcers and chronic gastritis. In mice, <i>C. albicans</i> induces gastritis without concurrent intestinal inflammation, suggesting that the stomach is particularly prone to fungal infection. We previously showed that <i>C. albicans</i> invasion in the limiting ridge does not extend to or elicit an inflammatory response in the adjacent glandular region, indicating regionalized gastritis in the murine stomach. However, the molecular pathways involved in the host response to <i>C. albicans</i> specifically in the limiting ridge have not been investigated. Here, we found that gastric dysbiosis was associated with <i>C. albicans</i> limiting ridge colonization and gastritis. We isolated the limiting ridge and evaluated the expression of over 90 genes involved in mucosal responses. <i>C. albicans</i> infection triggered a type 3 immune response marked by elevated <i>Il17a</i>, <i>Il17f</i>, <i>Il1b</i>, <i>Tnf</i>, and <i>Il36g</i>, as well as an upregulation of <i>Il12a</i>, <i>Il4</i>, <i>Il10</i>, and <i>l13</i>. Chemokine gene induction (including <i>Ccl2</i>, <i>Ccl3</i>, <i>Ccl4</i>, <i>Ccl1l</i>, <i>Cxcl1</i>, <i>Cxcl2</i>, <i>Cxcl9</i>, and <i>Cxcl10</i>) coincided with an influx of neutrophils, monocytes/macrophages, and eosinophils. Hyphal invasion caused tissue damage, epithelial remodeling, and upregulation of genes linked to epithelium signaling and antimicrobial responses in the limiting ridge. Our findings support a need for continued exploration into the interactions between the immunological milieu, the host microbiota, and clinical interventions such as the use of antibiotics and immunotherapeutic agents and their collective impact on invasive candidiasis risk.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0043824"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11629626/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142619585","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}

{"title":"A conserved interaction between the effector Sca4 and host clathrin suggests additional contributions for Sca4 during rickettsial infection.","authors":"Cassandra J Vondrak, Brandon Sit, Chanakan Suwanbongkot, Kevin R Macaluso, Rebecca L Lamason","doi":"10.1128/iai.00267-24","DOIUrl":"10.1128/iai.00267-24","url":null,"abstract":"<p><p>Intracellular bacterial pathogens deploy secreted effector proteins that manipulate diverse host machinery and pathways to promote infection. Although many effectors carry out a single function or interaction, there are a growing number of secreted effectors capable of interacting with multiple host factors. However, few effectors secreted by arthropod-borne obligate intracellular <i>Rickettsia</i> species have been linked to multiple host targets. Here, we investigated the conserved rickettsial secreted effector Sca4, which was previously shown to interact with host vinculin in donor cells to promote cell-to-cell spread in the model <i>Rickettsia</i> species <i>R. parkeri</i>. We discovered that Sca4 also binds the host cell protein clathrin heavy chain (CHC, <i>CLTC</i>) via a conserved segment in the Sca4 N-terminus. In mammalian host cells, ablation of <i>CLTC</i> expression or chemical inhibition of endocytosis reduced <i>R. parkeri</i> cell-to-cell spread<i>,</i> indicating that clathrin promotes efficient spread. Unexpectedly, the contribution of CHC to spread was independent of Sca4 and appeared restricted to the recipient host cell, suggesting that the Sca4-clathrin interaction regulates another aspect of the infectious lifecycle. Indeed, <i>R. parkeri</i> lacking Sca4 or expressing a Sca4 truncation unable to bind clathrin had markedly reduced burdens in tick cells, hinting at a cell type-specific function for the Sca4-clathrin interaction. Sca4 homologs from diverse <i>Rickettsia</i> species also bound clathrin, suggesting that the function of this novel effector-host interaction may be broadly important for rickettsial infection. We conclude that Sca4 has multiple targets during infection and that rickettsiae may manipulate host endocytic machinery to facilitate several stages of their life cycles.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0026724"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11629629/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142619579","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}

{"title":"Tail-specific protease is an essential <i>Chlamydia</i> virulence factor that mediates the differentiation of elementary bodies into reticulate bodies.","authors":"Arkaprabha Banerjee, Kaylee R Jacobs, Yihui Wang, Emma H Doud, Evelyn Toh, Barry D Stein, Amber L Mosley, Guangming Zhong, Richard P Morrison, Sandra G Morrison, Shuai Hu, Julie A Brothwell, David E Nelson","doi":"10.1128/iai.00436-24","DOIUrl":"10.1128/iai.00436-24","url":null,"abstract":"<p><p>Tail-specific proteases (Tsp) are members of a widely distributed family of serine proteases that commonly target and process periplasmic proteins in Gram-negative bacteria. The obligately intracellular, Gram-negative <i>Chlamydia</i> encode a highly conserved Tsp homolog whose target and function are unclear. We identified a <i>Chlamydia muridarum</i> mutant with a nonsense mutation in <i>tsp</i>. Differentiation of the <i>tsp</i> mutant elementary bodies into vegetative reticulate bodies was delayed at 37°C and completely blocked at 40°C. Tsp localized to <i>C. muridarum</i> cells but was not detected outside the inclusion, suggesting that it targets chlamydial rather than host proteins. The abundance of key chlamydia outer membrane complex and virulence-related proteins differed in wild-type and <i>tsp</i> mutant elementary bodies, consistent with the possibility that Tsp regulates developmental cycle progression. The altered abundances of chlamydial structural and virulence factors could explain why the mutant, but not an isogenic recombinant with wild-type <i>tsp</i>, was highly attenuated in a mouse intravaginal infection model. Thus, chlamydial Tsp is required for timely differentiation of elementary bodies into reticulate bodies <i>in vitro</i> and is an essential virulence factor <i>in vivo</i>.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0043624"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11629628/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142619597","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}

{"title":"Differential murine responses to <i>Schistosoma mansoni</i> eggs in the liver and small intestine lead to downmodulation of hepatic but not intestinal periovular granulomas.","authors":"Ashgan Montasser, Ahmad E Dakrory, Mohamed I M Ibrahim, Emad El Zayyat, Hatem Tallima, Rashika El Ridi","doi":"10.1128/iai.00362-24","DOIUrl":"10.1128/iai.00362-24","url":null,"abstract":"<p><p>To control schistosomiasis mansoni, it is important to attempt preventing the worms' egg-induced pathology in the liver and limiting pathogen transmission following egg exit from the intestines to the exterior. Therefore, the present study aimed to clarify the reasons behind the decades-long riddle of periovular granulomas downmodulation in the liver, but not the small intestine, with the progression of murine schistosomiasis mansoni. Outbred female CD-1 mice were percutaneously exposed to 15 <i>Schistosoma mansoni</i> cercariae. The liver and small intestine were collected from mice harboring a minimum of a worm couple at 8, 12, 16, and 20 weeks post-infection, assessed for egg counts/g and histopathological changes, and used to prepare Triton X-100 extracts. Content of cytokines, saturated and unsaturated fatty acids, triglycerides, cholesterol, reactive oxygen species, and uric acid per mg tissue extract proteins were evaluated using capture enzyme-linked immunosorbent assays, gas chromatography-flame ionization detector, and standard commercially available reagents, respectively. Examination of hematoxylin-eosin-stained tissue sections confirmed the decrease in size and changes in cellular composition of periovular granulomas in the liver but not the small intestine, associated with wide differences in released cytokines types and amounts, and content of the bioactive lipids, arachidonic and docosahexaenoic acids, reactive oxygen species, and uric acid. The results together disclosed that the downmodulation of hepatic, but not the small intestine, circumoval granulomas with the progression of murine <i>S. mansoni</i> naturally results from site- and tissue- specific immunological and biochemical responses to the egg-derived antigens and molecules and suggested that the intestines appear to harbor immune-privileged sites.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0036224"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11629614/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142667757","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}

{"title":"Article of Significant Interest in This Issue.","authors":"","doi":"10.1128/iai.00552-24","DOIUrl":"10.1128/iai.00552-24","url":null,"abstract":"","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":"92 12","pages":"e0055224"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11640281/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142800613","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}

{"title":"Transiently boosting Vγ9+Vδ2+ γδ T cells early in Mtb coinfection of SIV-infected juvenile macaques does not improve Mtb host resistance.","authors":"Erica C Larson, Amy L Ellis, Mark A Rodgers, Abigail K Gubernat, Janelle L Gleim, Ryan V Moriarty, Alexis J Balgeman, Yonne T de Menezes, Cassaundra L Ameel, Daniel J Fillmore, Skyler M Pergalske, Jennifer A Juno, Pauline Maiello, Harris B Chishti, Philana Ling Lin, Dale I Godfrey, Stephen J Kent, Daniel G Pellicci, Lishomwa C Ndhlovu, Shelby L O'Connor, Charles A Scanga","doi":"10.1128/iai.00313-24","DOIUrl":"10.1128/iai.00313-24","url":null,"abstract":"<p><p>Children living with HIV have a higher risk of developing tuberculosis (TB), a disease caused by the bacterium <i>Mycobacterium tuberculosis</i> (Mtb). Gamma delta (γδ) T cells in the context of HIV/Mtb coinfection have been understudied in children despite <i>in vitro</i> evidence suggesting γδ T cells assist with Mtb control. We investigated whether boosting a specific subset of γδ T cells, phosphoantigen-reactive Vγ9+Vδ2+ cells, could improve TB outcome using a nonhuman primate model of pediatric HIV/Mtb coinfection. Juvenile Mauritian cynomolgus macaques (MCM), equivalent to 4- to 8-year-old children, were infected intravenously (i.v.) with SIV. After 6 months, MCM were coinfected with a low dose of Mtb and then randomized to receive zoledronate (ZOL), a drug that increases phosphoantigen levels, (<i>n</i> = 5; i.v.) at 3 and 17 days after Mtb accompanied by recombinant human IL-2 (s.c.) for 5 days following each ZOL injection. A similarly coinfected MCM group (<i>n</i> = 5) was injected with saline as a control. Vγ9+Vδ2+ γδ T cell frequencies spiked in the blood, but not airways, of ZOL+IL-2-treated MCM following the first dose, however, were refractory to the second dose. At necropsy 8 weeks after Mtb, ZOL+IL-2 treatment did not reduce pathology or bacterial burden. γδ T cell subset frequencies in granulomas did not differ between treatment groups. These data show that transiently boosting peripheral γδ T cells with ZOL+IL-2 soon after Mtb coinfection of SIV-infected MCM did not improve Mtb host defense.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0031324"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11629613/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142545285","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}

{"title":"A type VI secretion system in <i>Burkholderia</i> species <i>cenocepacia</i> and <i>orbicola</i> triggers distinct macrophage death pathways independent of the pyrin inflammasome.","authors":"Nicole A Loeven, Clarrisa Dabi, Joseph P Pennington, Arianna D Reuven, Abigail P McGee, Bethany W Mwaura, James B Bliska","doi":"10.1128/iai.00316-24","DOIUrl":"10.1128/iai.00316-24","url":null,"abstract":"<p><p>The <i>Burkholderia cepacia</i> complex contains opportunistic pathogens that cause chronic infections and inflammation in the lungs of people with cystic fibrosis. Two closely related species within this complex are <i>Burkholderia cenocepacia</i> and the recently classified <i>Burkholderia orbicola. B. cenocepacia</i> and <i>B. orbicola</i> encode a type VI secretion system and the effector TecA, which is detected by the pyrin/caspase-1 inflammasome, and triggers macrophage inflammatory death. We previously showed that the pyrin inflammasome was dispensable for lung inflammation in mice infected with <i>B. orbicola</i> AU1054<i>,</i> indicating this species activates an alternative pathway of macrophage inflammatory death. Notably, <i>B. cenocepacia</i> strains J2315 and K56-2 can damage macrophage phagosomes, and K56-2 triggers activation of the caspase-11 inflammasome, which detects cytosolic lipopolysaccharide. Here, we investigated inflammatory cell death in pyrin- (<i>Mefv</i>^-/-) or caspase-1/caspase-11- (<i>Casp1/11^-/-</i>) deficient mouse macrophages infected with <i>B. cenocepacia</i> J2315 or K56-2 or <i>B. orbicola</i> AU1054 or PC184. Macrophage inflammatory death was measured by cleavage of gasdermin D protein, the release of cytokines IL-1α and IL-1β, and plasma membrane rupture. We found that J2315 and K56-2 are detected by the caspase-11 inflammasome in <i>Mefv</i>^-/- macrophages, resulting in IL-1β release. By contrast, inflammasome activation was not detected in <i>Mefv</i>^-/- macrophages infected with AU1054 or PC184. Instead, AU1054 triggered an alternative macrophage inflammatory death pathway that required TecA and resulted in plasma membrane rupture and IL-1α release. Structural modeling of TecA orthologs in <i>B. cenocepacia</i> and <i>B. orbicola</i> suggested that amino acid changes in the latter may underlie its ability to trigger a non-inflammasome macrophage death pathway.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0031624"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11629634/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142545284","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}

{"title":"Do white-footed mice, the main reservoir of the Lyme disease pathogen in the United States, clinically respond to the borrelial tenancy?","authors":"Artem S Rogovskyy, Vasilis C Pliasas, Ryan Buhrer, Keith Lewy, Dominique J Wiener, Yoonsung Jung, Jonathan Bova, Yuliya Rogovska, Sun J Kim, Eunhye Grace Jeon","doi":"10.1128/iai.00382-24","DOIUrl":"10.1128/iai.00382-24","url":null,"abstract":"<p><p>As white-footed mice, <i>Peromyscus leucopus</i>, are considered the primary animal reservoir of <i>Borreliella burgdorferi sensu stricto</i> (<i>Bb</i>), the main agent of Lyme disease (LD) in the United States, these animals represent the most relevant model to study borrelial spirochetes in the context of their natural life cycle. Previous studies have consistently demonstrated that although white-footed mice respond immunologically to the invasion of the Lyme pathogen, <i>P. leucopus</i> adults do not develop a clinically detectable disease. This tolerance, which is common for mammalian reservoirs of different pathogens, contrasts with detrimental anti-borrelial responses of C3H mice, a widely used animal model of LD, which always result in a clinical manifestation (e.g., arthritis). The current investigation is a follow-up of our recent study that already showed a relative quiescence of the spleen transcriptome for <i>Bb</i>-infected white-footed mice compared to the infected C3H mice. In an effort to identify the mechanism behind this tolerance, in this study, we have evaluated an extensive list of hematological and biochemical parameters measured in white-footed mice after their 70-day-long borrelial infection. Despite missing reference intervals for <i>Peromyscus</i> mice, our sex- and age-matched uninfected controls allowed us to assess the blood and serum parameters. In addition, for our assessment, we also utilized behavioral, immunological, and histological analyses. Collectively, by using the metrics reported herein, the present results have demonstrated clinical unresponsiveness of <i>P. leucopus</i> mice to the borrelial infection, presenting no restriction to a long-term host-pathogen co-existence.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0038224"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11629617/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142619583","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}

{"title":"C-di-AMP accumulation disrupts glutathione metabolism in <i>Listeria monocytogenes</i>.","authors":"Cheta Siletti, Matthew Freeman, Hung H Dang, Zepeng Tu, David M Stevenson, Daniel Amador-Noguez, John-Demian Sauer, TuAnh N Huynh","doi":"10.1128/iai.00440-24","DOIUrl":"10.1128/iai.00440-24","url":null,"abstract":"<p><p>C-di-AMP homeostasis is critical for bacterial stress response, cell wall integrity, and virulence. Except for osmotic stress response, the molecular mechanisms underlying other processes are not well defined. A <i>Listeria monocytogenes</i> mutant lacking both c-di-AMP phosphodiesterases, denoted as the ΔPDE mutant, is significantly attenuated in the mouse model of systemic infection. We utilized the ΔPDE mutant to define the molecular functions of c-di-AMP. RNAseq revealed that the ΔPDE mutant is significantly impaired for the expression of virulence genes regulated by the master transcription factor PrfA, which is activated by reduced glutathione (GSH) during infection. Subsequent quantitative gene expression analyses revealed that the ΔPDE strain is defective for PrfA-regulated gene expression both at the basal level and upon activation by GSH. We further found the ΔPDE strain to be significantly depleted for cytoplasmic GSH and impaired for GSH uptake. The ΔPDE strain was also deficient in GSH under conditions that activate GSH synthesis by the synthase GshF and upon constitutive expression of <i>gshF</i>, suggesting that c-di-AMP accumulation inhibits GSH synthesis activity or promotes GSH catabolism. A constitutively active PrfA* variant restored virulence gene expression in ΔPDE in broth cultures supplemented with GSH but did not rescue virulence defect <i>in vivo</i>. Therefore, virulence attenuation at high c-di-AMP is likely associated with defects outside of the PrfA regulon. For instance, the ΔPDE strain was sensitive to oxidative stress, a phenotype exacerbated in the absence of GshF. Our data reveal GSH metabolism as another pathway that is regulated by c-di-AMP.IMPORTANCEC-di-AMP regulates both bacterial pathogenesis and interactions with the host. Although c-di-AMP is essential in many bacteria, its accumulation also attenuates the virulence of many bacterial pathogens. Therefore, disrupting c-di-AMP homeostasis is a promising antibacterial treatment strategy and has inspired several studies that screened for chemical inhibitors of c-di-AMP phosphodiesterases. However, the molecular functions of c-di-AMP are still not fully defined, and the underlying mechanisms for attenuated virulence at high c-di-AMP levels are unclear. Our analyses in <i>Listeria monocytogenes</i> indicate that virulence-related defects are likely outside of the virulence gene regulon. We found c-di-AMP accumulation to impair <i>L. monocytogenes</i> virulence gene expression and disrupt GSH metabolism. Further studies are necessary to establish the relative contributions of these regulations to virulence and host adaptation.</p>","PeriodicalId":13541,"journal":{"name":"Infection and Immunity","volume":" ","pages":"e0044024"},"PeriodicalIF":2.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11629612/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142667755","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}