mBio最新文献

{"title":"The African swine fever virus gene MGF_360-4L inhibits interferon signaling by recruiting mitochondrial selective autophagy receptor SQSTM1 degrading MDA5 antagonizing innate immune responses.","authors":"Hualin Sun, Jifei Yang, Zhonghui Zhang, Mengli Wu, Zhancheng Tian, Ying Liu, Xiaoqiang Zhang, Jianhao Zhong, Songlin Yang, Yikang Chen, Jianxun Luo, Guiquan Guan, Hong Yin, Qingli Niu","doi":"10.1128/mbio.02677-24","DOIUrl":"10.1128/mbio.02677-24","url":null,"abstract":"<p><p>Multigene family (MGF) 360 genes, which are African swine fever virus (ASFV) virulence genes, primarily target key host immune molecules to suppress host interferon (IFN) production and interferon-stimulated gene (ISG) transcription, impairing host innate immune responses for efficient viral replication. However, the interactions between MGF 360 virulence genes and host molecules, as well as the mechanisms through which MGF 360 genes regulate host immune responses and IFN signaling, require further elucidation. In this study, we discovered that ASFV MGF_360-4L interacts with MDA5 and recruits the mitochondrial selective autophagy receptor SQSTM1 to degrade MDA5, thus impairing IFN signaling and compromising host innate immune responses. Furthermore, MGF_360-4L inhibits the interaction between MDA5 and MAVS, blocking ISG15-mediated ISGylation of MDA5. MGF_360-4L deficiency significantly attenuated virus-induced mitochondrial autophagy <i>in vitro</i>. Additionally, OAS1 ubiquitinates MGF_360-4L at residues K290, K295, and K327. Finally, a recombinant ASFV lacking the MGF_360-4L gene (ASFV-∆MGF_360-4L) was generated using ASFV-CN/SC/2019 as the backbone, which demonstrated that the replication kinetics of ASFV-∆MGF_360-4L in PAM cells were like those of the highly virulent parental ASFV-WT <i>in vitro</i>. Domestic pigs infected with ASFV-∆MGF_360-4L exhibited milder symptoms than those infected with parental ASFV-WT, and ASFV-∆MGF_360-4L-infected pigs presented with enhanced host innate antiviral immune response, confirming that the deletion of the MGF_360-4L gene from the ASFV genome highly attenuated virulence in pigs and provided effective protection against parental ASFV challenge. In conclusion, we identified a novel ASFV virulence gene, MGF_360-4L, further elucidating ASFV infection mechanisms and providing a new candidate for vaccine development.IMPORTANCEAfrican swine fever virus (ASFV) infection causes acute death in pigs, and there is currently no effective vaccine available for prevention. Multigene family (MGF) virulence genes have been shown to be crucial for ASFV's ability to evade host innate immune responses. However, the functions of most MGF genes remain unknown, which poses significant challenges for the development of ASFV vaccines and antiviral drugs. In this study, we identified a virulence gene of ASFV, MGF_360-4L, that targets and recruits the selective autophagy receptor p62 to mediate the degradation of the dsRNA sensor MDA5, thereby blocking interferon signaling. Additionally, it inhibits the ISG15-mediated ISGylation activation of MDA5. ASFV lacking MGF_360-4L showed reduced virulence and provided protection in pigs. Our data identify a novel virulence gene and provide new insights for ASFV vaccine development.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0267724"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of environmental exposures on T follicular helper cell function and implications on immunity: a comparison of Bangladeshi and American children.","authors":"Dana M Van Fossen, Hyunjae Cho, Lisa E Wagar, Jennie Z Ma, Julie Parsonnet, Rashidul Haque, Mark M Davis, William A Petri","doi":"10.1128/mbio.03980-24","DOIUrl":"10.1128/mbio.03980-24","url":null,"abstract":"<p><p>T follicular helper (Tfh) cells are crucial for B cell activation and subsequent antibody production. This functionality is influenced by surface markers such as CD40L, a costimulatory factor which promotes B cell activation, and CD57, which is a well-known marker of senescence. This study examined age-specific differences in Tfh cell function in Bangladeshi and American children. At age two, Bangladeshi children displayed impaired CD40L upregulation and significant CD57 downregulation upon stimulation. These patterns, not observed in American children of the same age, suggested an exhaustion-like phenotype potentially driven by environmental factors. Random forest and generalized estimating equations (GEE) modeling was used to analyze predictors of Tfh cell response to stimulation. Days since the last antibiotic treatment, total antibiotic treatments, diarrheal episodes, and malnutrition were identified as variables that significantly impacted the Tfh response to stimuli. To assess Tfh cell ability to promote antibody responses, we correlated Tfh functionality with antibody concentration post-vaccination and in response to infection with <i>Cryptosporidium</i>, an endemic apicomplexan parasite. Increased CD40L expression upon stimulation correlated positively with anti-Poliovirus type 2/3 neutralizing antibody and anti-Cp17 (a <i>Cryptosporidium</i> sporozoite antigen) IgA concentrations. In contrast, increased CD57 expression was significantly correlated with decreased anti-Cp17 IgA. This indicates that an activation-supportive phenotype (CD40L+) may be more effective in promoting immunity than a senescent phenotype (CD57+). Together, these findings suggest that early-life environmental exposures may program Tfh cell functionality, impacting immune response potential in settings with high pathogen exposure.</p><p><strong>Importance: </strong>T follicular helper (Tfh) cells are upstream mediators that shape the humoral immune response to specific antigens. The generation of an effective memory response to infection is vital to prevent subsequent reinfections. However, in areas with high burdens of exposure to infections, such as the urban community from Bangladesh studied here, children are consistently exposed to inflammatory pathogens. Specific environmental exposures significantly influenced Tfh cell activation and senescence phenotypes. Additionally, Tfh cell responses correlated with antibody concentrations following vaccination or infection, indicating that environmental factors may play a critical role in shaping effective immunity in early childhood.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0398024"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143586183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"XBB.1.5 monovalent vaccine induces lasting cross-reactive responses to SARS-CoV-2 variants such as HV.1 and JN.1, as well as SARS-CoV-1, but elicits limited XBB.1.5 specific antibodies.","authors":"Juan Manuel Carreño, Brian Lerman, Gagandeep Singh, Anass Abbad, Temima Yellin, Jordan Ehrenhaus, Miriam Fried, Jessica R Nardulli, Hyun Min Kang, Lubbertus C F Mulder, Charles Gleason, Komal Srivastava, Viviana Simon, Florian Krammer","doi":"10.1128/mbio.03607-24","DOIUrl":"10.1128/mbio.03607-24","url":null,"abstract":"<p><p>The evolution of the antibody response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is impacted by the nature and number of antigenic exposures. First-generation coronavirus disease 2019 (COVID-19) vaccines encoded an ancestral spike protein. Updated bivalent vaccines and breakthrough infections have shaped the intricate diversity of the polyclonal antibody response and specificity of individual antibody clones. We and others previously showed that bivalent vaccines containing the ancestral and Omicron (BA.5) spikes induce high levels of cross-reactive antibodies but undetectable BA.5-specific antibodies in serum. Here, we assessed sera collected before as well as 1 and 3 months following administration of an updated XBB.1.5 monovalent vaccine to individuals with diverse infection and vaccination histories. Vaccination increased neutralization against recent variants of concern, including HV.1, JN.1, and the vaccine-homologous XBB.1.5. Antibody binding and avidity against ancestral and XBB.1.5 antigens significantly increased after vaccination. However, antibody depletion experiments showed that most of the response was cross-reactive to the ancestral spike, and only low levels of XBB.1.5-specific antibodies to the spike or the receptor-binding domain were detected. Importantly, increased antibody levels were still detectable in circulation 3 months post-vaccination and cross-reacted with severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) as measured by pseudovirus neutralization and binding assays. Overall, our data suggest that the XBB.1.5 monovalent vaccine predominantly elicits a cross-reactive response imprinted by viral spike antigens encountered early during the pandemic.IMPORTANCEUpdated COVID-19 vaccine formulations and SARS-CoV-2 exposure history affect the antibody response to SARS-CoV-2. High titers of antibodies are induced in serum by XBB.1.5 monovalent vaccination. Antibody depletion experiments reveal that the majority of the antibody response is cross-reactive to the ancestral spike, despite vaccination increasing neutralization against recently circulating Omicron variants. Vaccine-induced SARS-CoV-2 antibodies cross-react with SARS-CoV-1 and remain in the bloodstream for at least 3 months after immunization.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0360724"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143557328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Standard mouse diets lead to differences in severity in infectious and non-infectious colitis.","authors":"Joshua E Denny, Julia N Flores, Nontokozo V Mdluli, Michael C Abt","doi":"10.1128/mbio.03302-24","DOIUrl":"10.1128/mbio.03302-24","url":null,"abstract":"<p><p><i>Clostridioides difficile</i> infects the large intestine and can result in debilitating and potentially fatal colitis. The intestinal microbiota is a major factor influencing the severity of disease following infection. Factors like diet that shape microbiota composition and function may modulate <i>C. difficile</i> colitis. Here, we report that mice fed two distinct standard mouse chows (LabDiet 5010 and LabDiet 5053) exhibited significantly different susceptibility to severe <i>C. difficile</i> infection. Both diets are grain-based with comparable profiles of macro and micronutrient composition. Diet 5010-fed mice had severe morbidity and mortality compared to Diet 5053-fed mice despite no differences in <i>C. difficile</i> colonization or toxin production. Furthermore, Diet 5053 protected mice from toxin-induced epithelial damage. This protection was microbiota-dependent as germ-free mice or mice harboring a reduced diversity microbiota fed Diet 5053 were not protected from severe infection. However, cohousing with mice harboring a complex microbiota restored the protective capacity of Diet 5053 but not Diet 5010. Metabolomic profiling revealed distinct metabolic capacities between Diet 5010- and Diet 5053-fed intestinal microbiotas. Diet 5053-mediated protection extended beyond <i>C. difficile</i> infection as Diet 5053-fed mice displayed less severe dextran sodium sulfate-induced colitis than Diet 5010-fed mice, highlighting a potentially broader capacity for Diet 5053 to limit colitis. These findings demonstrate that standard diet formulations in combination with the host microbiota can drive variability in severity of infectious and non-infectious murine colitis systems, and that diet holds therapeutic potential to limit the severity of <i>C. difficile</i> infection through modulating the functional capacity of the microbiota.IMPORTANCEDiet is a major modulator of the microbiota and intestinal health. This report finds that two different standard mouse diets starkly alter the severity of colitis observed in a pathogen-mediated (<i>Clostridioides difficile</i>) and non-infectious (dextran sodium sulfate) mouse colitis experimental systems. These findings in part explain study-to-study variability using these mouse systems to study disease. Since the gut microbiota plays a key role in intestinal homeostasis, diet-derived modulation of the microbiota is a promising avenue to control disease driven by intestinal inflammation and may represent a potential intervention strategy for at-risk patients.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0330224"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143692700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Acinetobacter baumannii</i> OmpA hinders host autophagy via the CaMKK2-reliant AMPK-pathway.","authors":"Kyungho Woo, Dong Ho Kim, Ho-Sung Park, Man Hwan Oh, Je Chul Lee, Chul Hee Choi","doi":"10.1128/mbio.03369-24","DOIUrl":"10.1128/mbio.03369-24","url":null,"abstract":"<p><p>Outer membrane protein A (OmpA) plays a vital role in the interactions between <i>Acinetobacter baumannii</i> and host cells. Autophagy is a defense mechanism that hinders the intracellular replication of bacteria, thereby safeguarding cells against microbial infections. While it has been observed that <i>A. baumannii</i> triggers cellular autophagy, the precise role of its virulence protein OmpA in this process remains uncertain. In this study, we investigated the effects of <i>A. baumannii</i> OmpA (AbOmpA) on autophagy and explored the underlying molecular mechanisms. We found that AbOmpA exerted its autophagy-suppressive effect through inhibition of CaMKK2 phosphorylation. Compared to the wild-type strain, the <i>ompA</i>-deletion mutant strain displayed considerably enhanced autophagy induction, <i>via</i> the AMPK-ULK1 pathway. AbOmpA hindered starvation-induced autophagy, while <i>A. baumannii</i>-Omp33 (AbOmp33) and <i>Escherichia coli</i>-OmpA (EcOmpA) did not. Importantly, we confirmed that exogenous AbOmpA suppressed autophagy through the CaMKK2-AMPK-ULK1 pathway during <i>A. baumannii</i> infection. These findings reveal a novel mechanism for AbOmpA-mediated autophagy evasion, providing new insights into the pathogenesis of <i>A. baumannii</i> infection.IMPORTANCE<i>Acinetobacter baumannii</i> is a significant clinical pathogen notorious for causing infections in hospitals. Its outer membrane protein A acts as a virulence factor and helps the bacteria evade host defenses. Autophagy is a defense mechanism that hinders the intracellular replication of bacteria. While it has been observed that <i>A. baumannii</i> triggers cellular autophagy, the precise role of its AbOmpA in this process remains uncertain. Our studies demonstrate the AbOmpA of <i>A. baumannii</i> inhibits the cellular defense process, autophagy, through the CaMKK2-AMPK-ULK1 signaling cascade, thereby enhancing bacterial survival. This insight into how AbOmpA bypasses autophagy sheds light on <i>A. baumannii</i> infection's novel virulence strategy and suggests possible treatments.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0336924"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Engineering of CD8⁺ T cells with an HIV-specific synthetic notch receptor to secrete broadly therapeutic antibodies for combining antiviral humoral and cellular immune responses.","authors":"Lina Meng, Haichi Zhao, Shangkun Chang, Weiting Li, Yinghui Tian, Ruihong Wang, Libian Wang, Tiejun Gu, Jiaxin Wu, Bin Yu, Chu Wang, Xianghui Yu","doi":"10.1128/mbio.03839-24","DOIUrl":"10.1128/mbio.03839-24","url":null,"abstract":"<p><p>The application of immunotherapeutic strategies, such as chimeric antigen receptor-T cells and broadly neutralizing antibodies (bNAbs), for the treatment of human immunodeficiency virus (HIV) infection is hindered by the latent reservoirs and viral escape. Achieving long-term control of viral load in the absence of antiretroviral therapy requires a combination approach utilizing these immunotherapeutic strategies. For this purpose, we developed novel anti-HIV-1 synthetic Notch (synNotch) receptor-T cells, termed CD4-17b-VN, which express both a bNAb (VRC01) and a bispecific T cell-engaging protein (N6-αCD3) with antigenic control. The synNotch receptor-expressing cells can sense the viral antigen presented on both HIV-1 particles and the surface of target cells. A human T cell line equipped with the CD4-17b-VN circuit could effectively control VRC01 and N6-αCD3 secretion upon sensitization, suppress the infection of diverse subtypes of HIV-1 strains, and mediate specific bypass cytotoxic activity against infected and latency-reactivated cells. Additionally, CD4-17b-VN CD8⁺ T cells exhibited long-lasting suppression of infected cells and stronger killing effect on latency-reactivated cells <i>in vitro</i>. Importantly, we demonstrated that the synNotch receptor did not increase susceptibility to HIV-1 infection in the engineered cells. Our study validates the concept of a synNotch platform-based T cell therapeutic approach that can deliver broadly therapeutic antibodies in an HIV-1 antigen-controlled manner, which may have important implications for the functional cure of AIDS.IMPORTANCEAdoptive transfer of effector T cells modified with a chimeric antigen receptor has been proposed as an applicable approach to treat human immunodeficiency virus (HIV) infection. The synNotch receptor (SNR) system serves as a versatile tool, enabling customized programming of input and output functions in mammalian cells. Herein, we report a novel synNotch platform-based approach for T cell engineering targeting both cell-free particles and infected cells by coupling antibody neutralization with cytotoxicity. Our findings demonstrate that the engineered CD4-17b SNR enables controllable production of functional anti-HIV-1 broadly neutralizing antibody and bispecific T cell-engaging protein upon recognition of the viral particle and cell surface antigens by the bifunctional synNotch-T cells. Human primary CD8⁺ T cells equipped with the bifunctional synNotch circuit CD4-17b-VN can effectively suppress long-term viral replication and reduce latency-reactivated cells <i>in vitro</i>, without the undesired risk of being infected by the virus, suggesting their potential candidacy for AIDS therapy with prospects for future clinical applications.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0383924"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Aspergillus terreus</i> sectorization: a morphological phenomenon shedding light on amphotericin B resistance mechanism.","authors":"David Eisele, Michael Blatzer, Anna Maria Dietl, Ulrike Binder, Christoph Müller, Ferry Hagen, Tongta Sae-Ong, Sascha Schäuble, Gianni Panagiotou, Roya Vahedi-Shahandashti, Cornelia Lass-Flörl","doi":"10.1128/mbio.03926-24","DOIUrl":"10.1128/mbio.03926-24","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Prolonged cultivation of certain filamentous fungi, including &lt;i&gt;Aspergillus terreus&lt;/i&gt;, on drug-free medium leads to degeneration and morphological heterogeneity, marked by the emergence of fluffy mycelium-type sectors. This phenomenon may indicate alterations in antifungal susceptibility profiles (particularly to amphotericin B (AmB) in &lt;i&gt;A. terreus&lt;/i&gt;), as well as reductions or losses in conidiation, sexuality, secondary metabolite production, and/or virulence. In the present study, various characteristics of an AmB-resistant wild-type (WT) strain and its AmB-susceptible sectorized derivative (ATSec) were characterized. Compared to WT, ATSec exhibited increased susceptibility to AmB, reduced sporulation, and comparable sterol contents and virulence in &lt;i&gt;Galleria mellonella&lt;/i&gt;. To elucidate the genes involved in AmB resistance, gene expression levels were compared between WT and ATSec with and without AmB treatment. The expression of P-type ATPase-related genes, which are implicated in membrane composition changes and consequently in AmB resistance, was significantly higher in the WT strain compared to ATSec. Moreover, the up-regulation of genes involved in the biosynthesis of polyketides-a diverse group of secondary metabolites-was higher in WT compared to ATSec, with a significant number of these genes also carrying at least one mutation. The findings of this study indicate that P-type ATPases may significantly be involved in AmB susceptibility and resistance observed in ATSec and WT strains. Additionally, mutations in polyketide synthase genes in ATSec may contribute to the phenotypic alterations associated with the sectorized phenotype.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Importance: &lt;/strong&gt;Prolonged cultivation of certain filamentous fungi, including Aspergillus terreus, on drug-free medium leads to degeneration and morphological heterogeneity, marked by the emergence of fluffy mycelium-type sectors. This phenomenon may indicate alterations in antifungal susceptibility profiles (particularly to amphotericin B (AmB) in A. terreus), as well as reductions or losses in conidiation, sexuality, secondary metabolite production, and/or virulence. In the present study, various characteristics of an AmB-resistant wild-type strain (WT) and its AmB-susceptible sectorized derivative (ATSec) were characterized. Compared to WT, ATSec exhibited increased susceptibility to AmB, reduced sporulation, and comparable sterol contents and virulence in Galleria mellonella. To elucidate the genes involved in AmB resistance, gene expression levels were compared between WT and ATSec with and without AmB treatment. The expression of P-type ATPase-related genes, which are implicated in membrane composition changes and consequently in AmB resistance, was significantly higher in the WT strain compared to ATSec. Moreover, the up-regulation of genes involved in the biosynthesis of polyketides - a diverse group of secondary metabolites - was higher in WT compared to ATSec, with a s","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0392624"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fission yeast metabolome dynamics during phosphate starvation and replenishment.","authors":"Ana M Sanchez, Aye K Kyaw, Sara Nunes Violante, Angad Garg, Justin R Cross, Stewart Shuman","doi":"10.1128/mbio.00241-25","DOIUrl":"10.1128/mbio.00241-25","url":null,"abstract":"<p><p>Inorganic phosphate is an essential nutrient acquired by cells from their environment and assimilated into myriad intracellular metabolites and macromolecules. Here, we characterize the metabolic responses of fission yeast to a 24 h interval of phosphate starvation, during which cells enter a state of G0 quiescence. Time-resolved profiling revealed that many key phosphometabolites were progressively depleted, including (i) NTPs, NDPs, and dNTPs; (ii) coenzyme A, NAD⁺, NADP⁺, NADH, and ADP-ribose; (iii) glycolysis pathway intermediates upstream of pyruvate; (iv) pentose phosphate pathway intermediates from 6-phosphogluconate to sedoheptulose-7-phosphate; (v) nucleotide sugars GDP-hexose, UDP-glucose/galactose, and UDP-GalNAc/GlcNAc; and (vi) phospholipid precursors glycerol-3-phosphate, CDP-choline, and glycerophosphocholine. By contrast, early Krebs cycle intermediates accumulated during phosphate starvation. Other metabolic changes included the following: (i) interdiction of <i>de novo</i> pyrimidine synthesis; (ii) depletion of <i>S</i>-adenosylmethionine and <i>S</i>-adenosylhomocysteine; (iii) transient accumulation of polyamine biosynthetic intermediates putrescine and 5-methylthioadenosine; (iv) accumulation of betaine (correlating with an increase in expression of <i>atd1</i> mRNA encoding aldehyde dehydrogenase); and (v) depletion of aminoadipate pathway intermediates 2-oxoadipate, 2-aminoadipate, and saccharopine. Replenishing phosphate after 24 h of starvation resulted in restoration of the pre-starvation metabolome (over 2 to 12 h) as cells exited quiescence and resumed growth.</p><p><strong>Importance: </strong>Fission yeast <i>Schizosaccharomyces pombe</i> is a valuable model system to study cellular phosphate homeostasis and the adaptive responses to chronic phosphate starvation. Previous analyses focused on changes in the fission yeast transcriptome and proteome during phosphate starvation-induced durable G0 quiescence. Here, we deployed metabolomics to survey the scope and temporal order of metabolite changes during 24 h of phosphate starvation and the kinetics of metabolic recovery after cells starved for 24 h are replenished with phosphate. These results contribute to a multi-omics understanding of how phosphate status impacts cell cycle, gene expression, metabolism, and chronological lifespan.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0024125"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143492658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of human herpesvirus homologs of infected cell protein 27 (ICP27) in the biogenesis, processing, and maturation of mRNAs.","authors":"Abel A Soto-Machuca, Gerardo E Ortiz, Javier Carbone-Schellman, Ignacio A Pastén-Ferrada, Angello Retamal-Díaz, Alexis M Kalergis, Pablo A González","doi":"10.1128/mbio.00291-25","DOIUrl":"10.1128/mbio.00291-25","url":null,"abstract":"<p><p>Herpesviruses are enveloped viruses with large double-stranded DNA genomes that are highly prevalent in the human population and elicit numerous types of clinical manifestations, from mild to severe. These viruses are classified into three subfamilies: <i>alpha</i>-, <i>beta</i>-, and <i>gammaherpesvirinae</i>, all capable of establishing life-long persistent infections in the host. As strict intracellular parasites, these viruses have evolved molecular determinants to support and modulate viral and host gene transcription processes during infection and the translation of messenger RNAs (mRNAs) to synthesize proteins that participate in cellular pathways promoting their replication cycles and virion formation. Notably, some of these proteins have functional RNA-binding domains consisting of arginine-glycine-glycine (RGG) amino acid (aa) sequences that, when methylated, regulate their nucleic acid-binding capacities and can influence the export of mRNAs lacking introns from the nucleus into the cytoplasm. Additional domains and motifs in these proteins mediate their interactions with regulatory proteins related to RNA splicing, either promoting or repressing mRNA processing. Notably, all human herpesviruses (HHVs) encode in their genomes proteins that share homology with infected cell protein 27 (ICP27) of herpes simplex virus type 1 (HSV-1), which can significantly impact the biogenesis of mRNAs and their processing during infection. Here, we review and discuss the roles of ICP27 and the corresponding homologs encoded in different human herpesviruses, focusing on their similarities and differences in structure and function. A more profound knowledge of the role of key viral factors required for effective herpesvirus replication could aid in the design and identification of novel antivirals to treat the diseases produced by these viruses.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0029125"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143541824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The <i>Pseudomonas aeruginosa</i> T3SS can contribute to traversal of an <i>in situ</i> epithelial multilayer independently of the T3SS needle.","authors":"Eric Jedel, Daniel Schator, Naren G Kumar, Aaron B Sullivan, Arne Rietsch, David J Evans, Suzanne M J Fleiszig","doi":"10.1128/mbio.00266-25","DOIUrl":"10.1128/mbio.00266-25","url":null,"abstract":"<p><p>Multilayered epithelia lining our tissue surfaces normally resist traversal by opportunistic bacteria. Previously, we developed a strategy to experimentally perturb this resistance <i>in situ</i> in the corneas of mouse eyes and used it to show that traversal of a multilayered epithelium by <i>Pseudomonas aeruginosa</i> requires ExsA, the transcriptional activator of its type 3 secretion system (T3SS). Here, we developed a novel strategy for quantitatively localizing individual traversing bacteria within the <i>in situ</i> multilayered corneal epithelium and explored the contributions of T3SS components. The results showed that T3SS translocon and T3SS effector mutants had reduced epithelial traversal efficiency. Surprisingly, a Δ<i>pscC</i> mutant unable to assemble the T3SS needle traversed as efficiently as wild-type <i>P. aeruginosa</i>, while a Δ<i>exsD</i> mutant \"constitutively on\" for T3SS expression was traversal defective. The dispensability of the T3SS needle for effector-mediated traversal was confirmed using a mutant lacking the T3SS operon except for the effector genes (Δ<i>pscU-L</i> mutant). That mutant reacquired the ability to traverse if complemented with rhamnose-inducible <i>exsA</i>, but not if the effector genes were also deleted (Δ<i>pscU-L</i>Δ<i>exoSTY</i>). Western immunoblot confirmed ExoS in culture supernatants of rhamnose-induced <i>exsA</i>-complemented Δ<i>pscU-L</i> mutants lacking all T3SS needle protein genes. Together, these results show that epithelial traversal by <i>P. aeruginosa</i> can involve T3SS effectors and translocon proteins independently of the T3SS needle previously thought essential for T3SS function. This advances our understanding of <i>P. aeruginosa</i> pathogenesis and has relevance to the development of therapeutics targeting the T3SS system.IMPORTANCEWhile the capacity to cross an epithelial barrier can be a critical step in bacterial pathogenesis, our understanding of the mechanisms involved is derived largely from cell culture experimentation. The latter is due to the practical limitations of <i>in vivo</i>/<i>in situ</i> models and the challenge of visualizing individual bacteria in the context of host tissue. Here, factors used by <i>P. aeruginosa</i> to traverse an epithelial multilayer <i>in situ</i> were studied by (i) leveraging the transparent properties and superficial location of the cornea, (ii) using our established method for enabling bacterial traversal susceptibility, and (iii) developing a novel strategy for accurate and quantitative localization of individual traversing bacteria <i>in situ</i>. Outcomes showed that T3SS translocon and T3SS effector proteins synergistically contribute to epithelial traversal efficiency independently of the T3SS needle. These findings challenge the assumption that the T3SS needle is essential for T3SS effectors or translocon proteins to contribute to bacterial pathogenesis.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0026625"},"PeriodicalIF":5.1,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143625341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}