mBio最新文献

{"title":"Persistent articular infection and host reactive response contribute to <i>Brucella</i>-induced spondyloarthritis in SKG mice.","authors":"Jerome S Harms, Michael Lasarev, Thomas Warner, Sergio Costa Oliveira, Judith A Smith","doi":"10.1128/mbio.00542-25","DOIUrl":"10.1128/mbio.00542-25","url":null,"abstract":"<p><p>Brucellosis, one of the most prevalent zoonotic diseases worldwide, often results in osteoarticular complications including large joint and axial arthritis mimicking spondyloarthritis. To model this chronic manifestation, we infected autoimmunity-prone SKG mice containing a mutation in the T cell adaptor ZAP-70 with <i>Brucella</i> species. <i>B. melitensis</i> infection resulted in a fully penetrant, readily scoreable disease involving large joint wrist and foot arthritis, peri-ocular inflammation, and less frequent scaly paw rash. Infection with <i>B. abortus</i> resulted in similar manifestations, although with delayed arthritis onset, and <i>B. neotomae</i> revealed sex differences, with a more severe disease in females. Heat-killed <i>Brucella</i> did not induce arthritis, evincing a requirement for viable infection. Across species, splenic CFU correlated well with final clinical score at 12 weeks (ρ = 0.79 and <i>P</i> < 0.001). Moreover, viable <i>Brucella</i> was recovered from the paws at 12 weeks, consistent with persistent articular infection. Mice infected with a <i>Brucella</i>Δ<i>tcpB</i> mutant lacking a Type IV secretion system-dependent mediator displayed an intermediate phenotype without significant differences in splenic CFU. Thus, the degree of arthritis did not strictly correlate with the degree of systemic infection, but it suggested an additional reactive component. Together, these data suggest that <i>Brucella</i>-induced spondyloarthritis reflects both persistent colonization and excess host reactivity. Moreover, the sensitivity of the SKG model to different species and mutants will provide new opportunities for dissecting correlates of <i>Brucella</i> virulence and host immunity.IMPORTANCEBrucellosis, a bacterial infection acquired from herd animals, remains one of the most common zoonotic diseases worldwide. Chronic infection often results in spondyloarthritis-like complications. Investigation into pathogenesis has been limited by the lack of overt disease in standard laboratory mice. We addressed this issue using spondyloarthritis-susceptible SKG mice. Upon infection with <i>B. melitensis</i>, SKG mice develop robust, fully penetrant large joint arthritis. Arthritis development required viable bacteria, and live <i>Brucella</i> persisted in paw tissue out to 12 weeks. Disease onset, severity, and manifestations varied upon infection with different <i>Brucella</i> species and mutants, suggesting an additional immune reactive component. Together, these results suggest that this new model will be very useful to the scientific community for determining correlates of bacterial virulence leading to clinical disease.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0054225"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144011577","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":"A human-ACE2 knock-in mouse model for SARS-CoV-2 infection recapitulates respiratory disorders but avoids neurological disease associated with the transgenic K18-hACE2 model.","authors":"Anna Pons-Grífols, Ferran Tarrés-Freixas, Mònica Pérez, Eva Riveira-Muñoz, Dàlia Raïch-Regué, Daniel Perez-Zsolt, Jordana Muñoz-Basagoiti, Barbara Tondelli, Edwards Pradenas, Nuria Izquierdo-Useros, Sara Capdevila, Júlia Vergara-Alert, Victor Urrea, Jorge Carrillo, Ester Ballana, Stephen Forrow, Bonaventura Clotet, Joaquim Segalés, Benjamin Trinité, Julià Blanco","doi":"10.1128/mbio.00720-25","DOIUrl":"10.1128/mbio.00720-25","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Animal models have been instrumental in elucidating the pathogenesis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and in testing coronavirus disease 2019 (COVID-19) vaccines and therapeutics. Wild-type (WT) mice are not susceptible to many SARS-CoV-2 variants, and therefore, transgenic K18-hACE2 mice have emerged as a standard model system. However, this model is characterized by a severe disease, particularly associated with neuroinfection, which leads to early humane endpoint euthanasia. Here, we established a novel knock-in (KI) mouse model by inserting the original K18-hACE2 transgene into the collagen type I alpha chain (COL1A1) locus using a recombinase-mediated cassette exchange (RMCE) system. Once the Col1a1-K18-hACE2 mouse colony was established, animals were challenged with a B.1 SARS-CoV-2 (D614G) isolate and were monitored for up to 14 days. Col1a1-K18-hACE2 mice exhibited an initial weight loss similar to the K18-hACE2 transgenic model but did not develop evident neurologic clinical signs. The majority of Col1a1-K18-hACE2 mice did not reach the pre-established humane endpoint, showing a progressive weight gain 9 days postinfection (dpi). Importantly, despite this apparent milder pathogenicity of the virus in this mouse model compared to the K18-hACE2 transgenic model, high levels of viral RNA were detected in the lungs, oropharyngeal swab, and nasal turbinates. Moreover, the remaining lesions and inflammation in the lungs were still observed 14 dpi. In contrast, although low-level viral RNA could be detected in a minority of Col1a1-K18-hACE2 animals, no brain lesions were observed at any timepoint. Overall, Col1a1-K18-hACE2 mice constitute a new model for investigating SARS-CoV-2 pathogenesis and treatments, with potential implications for studying long-term COVID-19 sequelae.&lt;b&gt;IMPORTANCE&lt;/b&gt;K18-hACE2 mice express high levels of the human protein angiotensin-converting enzyme 2 (ACE2), the receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and are therefore susceptible to infection by this virus. These animals have been crucial to understanding viral pathogenesis and to testing coronavirus disease 2019 (COVID-19) vaccines and antiviral drugs. However, K18-hACE2 often dies after infection with initial SARS-CoV-2 variants, likely due to a massive brain infection that does not occur in humans. Here, we used a technology known as knock-in (KI) that allows for the targeted insertion of a gene into a mouse, and we have generated a new human ACE2 (hACE2) mouse. We have characterized this new animal model demonstrating that, upon challenge with SARS-CoV-2, the virus replicates in the respiratory tract, damaging lung tissue and causing inflammation. In contrast to K18-hACE2 mice, only limited or no brain infection could be detected in this new model. After 14 days, most animals recovered from the infection, although lung tissue lesions were still observed. This new model could be ins","PeriodicalId":18315,"journal":{"name":"mBio","volume":"16 5","pages":"e0072025"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12077128/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144064098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RAB5 is a host dependency factor for the generation of SARS-CoV-2 replication organelles.","authors":"Yuexuan Chen, Susanne Klute, Konstantin Maria Johannes Sparrer, Ruth Serra-Moreno","doi":"10.1128/mbio.03314-24","DOIUrl":"10.1128/mbio.03314-24","url":null,"abstract":"<p><p>Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a threat due to the emergence of variants with increased transmissibility and enhanced escape from immune responses. Like other coronaviruses before, SARS-CoV-2 likely emerged after its transmission from bats. The successful propagation of SARS-CoV-2 in humans might have been facilitated by usurping evolutionarily conserved cellular factors to execute crucial steps in its life cycle, such as the generation of replication organelles-membrane structures where coronaviruses assemble their replication-transcription complex. In this study, we found that RAB5, which is highly conserved across mammals, is a critical host dependency factor for the replication of the SARS-CoV-2 genome. Our results also suggest that SARS-CoV-2 uses RAB5⁺ membranes to build replication organelles with the aid of COPB1, a component of the COP-I complex, and that the virus protein NSP6 participates in this process. Hence, targeting NSP6 represents a promising approach to interfere with SARS-CoV-2 RNA synthesis and halt its propagation.IMPORTANCEIn this study, we sought to identify the host dependency factors that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses for the generation of replication organelles: cellular membranous structures that SARS-CoV-2 builds in order to support the replication and transcription of its genome. We uncovered that RAB5 is an important dependency factor for SARS-CoV-2 replication and the generation of replication organelles, and that the viral protein NSP6 participates in this process. Hence, NSP6 represents a promising target to halt SARS-CoV-2 replication.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0331424"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12077180/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143753244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Moonlighting enzymes of <i>Borrelia burgdorferi</i>.","authors":"Jorge L Benach","doi":"10.1128/mbio.00279-25","DOIUrl":"10.1128/mbio.00279-25","url":null,"abstract":"<p><p>Moonlighting enzymes are increasingly recognized in bacteria with dual functions depending on whether they are intracellular or expressed on the surface. Enzymes of the glycolytic pathway are among the most frequently associated with moonlighting functions and lack the signal sequences needed to deliver them to the cell surface. Once these enzymes are on the surface, they perform functions that are associated with pathogenesis and development of infection through interaction with host substrates. One such interaction is adhesion. <i>Borrelia burgdorferi,</i> the etiologic agent of Lyme disease, must encounter a wide number of different tissues and substrates from ticks to mammalian hosts to complete its life cycle and persist. The phosphomannose isomerase of this organism has a moonlighting function, interacting with collagen IV, a main component of the basal lamina. It is abundant in the skin, which is the site of the initial infection of <i>B. burgdorferi</i>.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0027925"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12077153/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143764286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal analysis of lung immune dynamics in lethal <i>Coccidioides posadasii</i> infection.","authors":"Oscar A Davalos, Aimy Sebastian, Nicole F Leon, Margarita V Rangel, Nadia Miranda, Deepa K Murugesh, Ashlee M Phillips, Katrina K Hoyer, Nicholas R Hum, Gabriela G Loots, Dina R Weilhammer","doi":"10.1128/mbio.02562-24","DOIUrl":"10.1128/mbio.02562-24","url":null,"abstract":"<p><p>Coccidioidomycosis, or Valley fever, is a lung disease caused by inhalation of <i>Coccidioides</i> fungi, prevalent in the Southwestern United States, Mexico, and parts of Central and South America. Annually, the United States reports 10,000-20,000 cases, although those numbers are expected to increase as climate change expands the fungal geographic range. While 60% of infections are asymptomatic, 40% symptomatic infections are often misdiagnosed due to similarities with bronchitis or pneumonia. A small subset of infection progress to severe illness, necessitating a better understanding of immune responses during lethal infection. Using single-cell RNA sequencing and spatial transcriptomics, we characterized lung responses during <i>Coccidioides</i> infection. We identified monocyte-derived <i>Spp1</i>-expressing macrophages as potential mediators of tissue remodeling and fibrosis, marked by high expression of profibrotic and proinflammatory transcripts. These macrophages showed elevated TGF-β and IL-6 signaling, pathways involved in fibrosis pathogenesis. Additionally, we observed significant neutrophil infiltration and defective lymphocyte responses, indicating severe adaptive immunity dysregulation in lethal, acute infection. These findings enhance our understanding of <i>Coccidioides</i> infection and suggest new therapeutic targets.IMPORTANCECoccidioidomycosis, commonly known as Valley fever, is a lung disease caused by the inhalation of <i>Coccidioides</i> fungi, which is prevalent in the Southwestern United States, Mexico, and parts of Central and South America. With climate change potentially expanding the geographic range of this fungus, understanding the immune responses during severe infections is crucial. Our study used advanced techniques to analyze lung responses during <i>Coccidioides</i> infection, identifying specific immune cells that may contribute to tissue damage and fibrosis. These findings provide new insights into the disease mechanisms and suggest potential targets for therapeutic intervention, which could improve outcomes for patients suffering from severe Valley fever.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0256224"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12077212/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142750999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual oxic-anoxic co-culture enables direct study of anaerobe-host interactions at the airway epithelial interface.","authors":"Patrick J Moore, Kayla Hoffman, Sara Ahmed, Joshua R Fletcher, Talia D Wiggen, Sarah K Lucas, Sabrina J Arif, Adam J Gilbertsen, Leslie A Kent, Jessica K Fiege, Ryan A Langlois, Scott M O'Grady, Ryan C Hunter","doi":"10.1128/mbio.01338-24","DOIUrl":"10.1128/mbio.01338-24","url":null,"abstract":"<p><p>Strict and facultative anaerobic bacteria are widely associated with both acute and chronic airway diseases. However, their potential role(s) in disease pathophysiology remains poorly understood due to inherent limitations of existing laboratory models and conflicting oxygen demands between anaerobes and host cells. To address these limitations, here, we describe a dual oxic-anoxic culture (DOAC) approach that maintains an oxygen-limited microenvironment at the apical epithelial interface while host cells are oxygenated basolaterally. This platform enables epithelial-anaerobe co-culture for ~48 h, and we demonstrate its utility by evaluating reciprocal interactions between the oxygen-sensitive anaerobic bacterium, <i>Fusobacterium nucleatum,</i> and oxygen-demanding airway epithelial cells at the transcriptional level. Using bulk RNAseq, we demonstrate that epithelial colonization results in altered gene expression by <i>F. nucleatum,</i> highlighted by the differential expression of genes associated with virulence, ethanolamine and lysine metabolism, metal uptake, and other transport processes. We also combine DOAC with single-cell RNA sequencing to reveal a cell type-specific transcriptional response of the airway epithelium to <i>F. nucleatum</i> infection, including the increased expression of inflammatory marker genes and cancer-associated pathways. Together, these data illustrate the versatility of DOAC while revealing new insights into anaerobe-host interactions and their mechanistic contributions to airway disease pathophysiology.IMPORTANCEConflicting oxygen demands between anaerobes and host cells present a significant barrier to <i>in vitro</i> modeling of how these cell types interact. To this end, the significance of our dual oxic-anoxic culture (DOAC) approach lies in its ability to maintain anaerobe and epithelial viability during co-culture, paving the way for new insights into the role(s) of anaerobic microbiota in disease. We use DOAC to interrogate reciprocal interactions between the airway epithelium and <i>Fusobacterium nucleatum</i>-an anaerobic commensal with pathogenic potential. Given its link to a range of diseases, from localized infections to various cancers, these data showing how <i>F. nucleatum</i> bacterium re-shapes its metabolism and virulence upon epithelial colonization provide new mechanistic insight into <i>F. nucleatum</i> physiology and how the host responds. We use <i>F. nucleatum</i> as our model, but the DOAC platform motivates additional studies of the gut, lung, and oral cavity, where host-anaerobe interactions and the underlying mechanisms of pathogenesis are poorly understood.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":"16 5","pages":"e0133824"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12077211/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144011579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Pseudomonas aeruginosa</i> population dynamics in a vancomycin-induced murine model of gastrointestinal carriage.","authors":"Marine Lebrun-Corbin, Bettina H Cheung, Karthik Hullahalli, Katherine G Dailey, Keith Bailey, Matthew K Waldor, Richard G Wunderink, Kelly E R Bachta, Alan R Hauser","doi":"10.1128/mbio.03136-24","DOIUrl":"10.1128/mbio.03136-24","url":null,"abstract":"<p><p><i>Pseudomonas aeruginosa</i> is a common nosocomial pathogen and a major cause of morbidity and mortality in hospitalized patients. Multiple reports highlight that <i>P. aeruginosa</i> gastrointestinal colonization may precede systemic infections by this pathogen. Gaining a deeper insight into the dynamics of <i>P. aeruginosa</i> gastrointestinal carriage is an essential step in managing gastrointestinal colonization and could contribute to preventing bacterial transmission and progression to systemic infection. Here, we present a clinically relevant mouse model relying on parenteral vancomycin pretreatment and a single orogastric gavage of a controlled dose of <i>P. aeruginosa</i>. Robust carriage was observed with multiple clinical isolates, and carriage persisted for up to 60 days. Histological and microbiological examination of mice indicated that this model indeed represented carriage and not infection. We then used a barcoded <i>P. aeruginosa</i> library along with the sequence tag-based analysis of microbial populations (STAMPR) analytic pipeline to quantify bacterial population dynamics and bottlenecks during the establishment of the gastrointestinal carriage. Analysis indicated that most of the <i>P. aeruginosa</i> population was rapidly eliminated in the stomach, but the few bacteria that moved to the small intestine and the cecum expanded rapidly. Hence, the stomach constitutes a significant barrier against gastrointestinal carriage of <i>P. aeruginosa,</i> which may have clinical implications for hospitalized patients.</p><p><strong>Importance: </strong>While <i>Pseudomonas aeruginosa</i> is rarely part of the normal human microbiome, carriage of the bacterium is quite frequent in hospitalized patients and residents of long-term care facilities. <i>P. aeruginosa</i> carriage is a precursor to infection. Options for treating infections caused by difficult-to-treat <i>P. aeruginosa</i> strains are dwindling, underscoring the urgency to better understand and impede pre-infection stages, such as colonization. Here, we use vancomycin-treated mice to model antibiotic-treated patients who become colonized with <i>P. aeruginosa</i> in their gastrointestinal tracts. We identify the stomach as a major barrier to the establishment of gastrointestinal carriage. These findings suggest that efforts to prevent gastrointestinal colonization should focus not only on judicious use of antibiotics but also on investigation into how the stomach eliminates orally ingested <i>P. aeruginosa</i>.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":"16 5","pages":"e0313624"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12077156/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144031341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lysine polyphosphate modifications contribute to virulence factors in <i>Pseudomonas aeruginosa</i>.","authors":"Kirsten Lehotsky, Nolan Neville, Isabella Martins, Keith Poole, Zongchao Jia","doi":"10.1128/mbio.00855-25","DOIUrl":"10.1128/mbio.00855-25","url":null,"abstract":"<p><p>Inorganic polyphosphate (polyP) is a universally conserved polymer involved in various biological processes, but its role as a direct protein regulator remains largely unexplored. Lysine polyphosphate modification (KPM), a strong but non-covalent interaction between polyP and lysine-rich protein sequences, has not been functionally characterized until now. In this study, we present the first investigation into KPM's biological significance using <i>Pseudomonas aeruginosa</i>, a critical priority pathogen known for its antibiotic resistance and virulence. We identified two essential bacterial proteins, EngA and SrmB, as novel KPM targets. Through site-specific lysine deletions, we demonstrated that disrupting lysine-polyP interactions severely impairs biofilm formation and significantly reduces the production of key virulence factors, including pyoverdine and pyocyanin. These findings establish a direct functional link between polyP and bacterial pathogenicity mediated by KPM. Our results highlight KPM as a previously unrecognized regulatory mechanism critical for controlling bacterial virulence factors. This work uncovers the first functional role of KPM and its importance in regulating virulence phenotypes in a major human pathogen.IMPORTANCEPolyphosphate is commonly known for its roles in metabolism and stress response. How inorganic polyphosphate (polyP) facilitates bacterial virulence has remained largely elusive. This study reveals that lysine polyphosphate modification (KPM), a chemical interaction between polyP and lysine-rich proteins, is essential for bacterial survival and pathogenicity in <i>P. aeruginosa</i>, a harmful microbe responsible for difficult-to-treat infections. We discovered that disrupting KPM in key proteins impairs the bacteria's ability to form protective biofilms and produce harmful toxins. This previously unknown biological process links polyP to protein function in controlling bacterial virulence factors. Our findings open new possibilities for developing anti-virulence therapies aimed at reducing bacterial infections without promoting antibiotic resistance.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":"16 5","pages":"e0085525"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12077175/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144034355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation of inositol polyphosphates through a phospholipase C-independent pathway involving carbohydrate and sphingolipid metabolism in <i>Trypanosoma cruzi</i>.","authors":"Mayara S Bertolini, Sabrina E Cline, Miguel A Chiurillo, Brian S Mantilla, Aharon Eidex, Logan P Crowe, Danye Qiu, Henning J Jessen, Adolfo Saiardi, Roberto Docampo","doi":"10.1128/mbio.03318-24","DOIUrl":"10.1128/mbio.03318-24","url":null,"abstract":"<p><p>Inositol phosphates are involved in a myriad of biological roles and activities such as Ca²⁺ signaling, phosphate homeostasis, energy metabolism, and disease pathogenicity. In <i>Saccharomyces cerevisiae,</i> synthesis of inositol phosphates occurs through the phosphoinositide phospholipase C (PLC)-catalyzed hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP₂) into inositol 1,4,5-trisphosphate (IP₃) and diacylglycerol and further IP₃ phosphorylation by additional kinases that leads to the formation of highly phosphorylated inositol derivatives, known as inositol pyrophosphates. Inositol-tetrakisphosphate 1-kinase (ITPK1) is an enzyme that mediates a PLC-independent inositol polyphosphate synthesis through phosphorylation of inositol monophosphates and other intermediates in the cytosol. In this work, we identified and characterized a <i>Trypanosoma cruzi</i> ITPK1 (TcITPK1) homolog. The ability of TcITPK1 to act as the mediator for this alternative pathway was established through <i>plc1</i>Δ and <i>plc1</i>Δ <i>isc1</i>Δ yeast complementation assays and SAX-HPLC analyses of radioactively labeled inositol. TcITPK1 localizes to the cytosol, and knockout attempts of <i>TcITPK1</i> revealed that only one allele was replaced by the DNA donor cassette at the specific locus, suggesting that <i>null</i> alleles may have lethal effects in epimastigotes. Ablation of <i>T. cruzi</i> phosphoinositide phospholipase C 1 (<i>TcPI-PLC1</i>) affected the synthesis of IP₃ from glucose 6-phosphate but did not affect the synthesis of inositol polyphosphates, while ablation of inositol phosphosphingolipid phospholipase (<i>TcISC1</i>) affected the synthesis of inositol polyphosphates, thus revealing that the PLC-independent pathway using either glucose 6-phosphate or inositol phosphoceramide is involved in the synthesis of inositol polyphosphates, while the PLC-dependent pathway is involved in IP₃ formation needed for Ca²⁺ signaling.</p><p><strong>Importance: </strong>Millions of people are infected with <i>Trypanosoma cruzi,</i> and the current treatment is not satisfactory. Inositol pyrophosphates have been established as important signaling molecules. Our work demonstrates the presence of a phospholipase C-independent pathway for the synthesis of inositol pyrophosphates in <i>T. cruzi</i>. Furthermore, we demonstrate that this pathway starts with the synthesis of inositol monophosphates from glucose 6-phosphate or from inositol phosphoceramide, linking it to carbohydrate and sphingolipid metabolism. The essentiality of the pathway for the survival of <i>T. cruzi</i> infective stages makes it an ideal drug target for treating American trypanosomiasis.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0331824"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12077091/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143764277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of novel antifungal drugs via screening repurposing libraries against <i>Coccidioides posadasii</i> spherule initials.","authors":"Sarah Saeger, Kathryn West-Jeppson, Yu-Rou Liao, Althea Campuzano, Jieh-Juen Yu, Jose Lopez-Ribot, Chiung-Yu Hung","doi":"10.1128/mbio.00205-25","DOIUrl":"10.1128/mbio.00205-25","url":null,"abstract":"<p><p>Coccidioidomycosis or valley fever is a treatment-limited fungal infection endemic to the alkaline deserts of North and South America for which two classes of antifungals are typically used: the polyenes and the triazoles. In light of the limited usefulness of the echinocandins and a growing trend of azole resistance, it is essential that we identify novel antifungals. In this study, we have developed and optimized a screening methodology for identifying potential antifungals effective against <i>Coccidioides</i> spherule initials using a metabolic assay, used it to screen four diverse drug libraries with limited drug overlap, and established safety and efficacy data for a majority of the compounds, including the Broad Repurposing Hub, Prestwick Chemicals 1520, Selleck L8200 Anti-parasitic, and MedChemExpress CNS Penetrants libraries. Hits were defined as compounds with strong metabolic inhibition (≥70%), which were significantly different compared to the median plate readout (B-scores ≤ -3). We identified 30 promising hits and found 12 compounds exhibiting half-maximal inhibitory concentrations below 6 µM. Among these, oxethazaine, niclosamide ethanolamine, 10058-F4, niclosamide (NIC), and pentamidine isethionate showed synergy with amphotericin B, suggesting their potential use in combination therapy. Further assessment of lead compounds' effects on spherules was conducted by image flow cytometry. Additionally, we explored the potential to use an attenuated, Biosafety Level 2 containment mutant, <i>C. posadasii</i> ∆<i>cts2</i>/∆<i>ard1</i>/∆<i>cts3</i> (∆T), as a surrogate model for drug screening. Overall, our findings provide a foundation for future research focused on screening and developing novel coccidioidomycosis treatments.IMPORTANCEThe antifungal treatment arsenal is especially limited against <i>Coccidioides</i>. Due to toxicity concerns, amphotericin B is generally reserved for triazole-recalcitrant infections. Recent laboratory susceptibility tests show an increase in fluconazole resistance, highlighting a need for new treatments. We have developed a large-scale metabolic screening assay under Biosafety Level 3 containment to identify existing drugs with novel activity against <i>Coccidioides</i> spherules. This drug-repurposing approach represents a convenient and cost-effective strategy to increase the available antifungals effective against these infections.</p>","PeriodicalId":18315,"journal":{"name":"mBio","volume":" ","pages":"e0020525"},"PeriodicalIF":5.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12077158/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143710596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}