Mycobacteria (London, England)最新文献

{"title":"C3HeB/FeJ mice with chronic <i>Mycobacterium avium</i> complex pulmonary infection exhibit impaired respiratory function but not necrotising granulomatous disease.","authors":"Timothy David Shaw, Camron M Pearce, Ha Lam, Ilham M Alshiraihi, Taru Dutt, Andres Obregon-Henao, Marcella Henao-Tamayo, Mary Jackson, Mercedes Gonzalez-Juarrero","doi":"10.1186/s44350-025-00004-7","DOIUrl":"10.1186/s44350-025-00004-7","url":null,"abstract":"<p><strong>Background: </strong><i>Mycobacterium avium</i> complex (MAC) is driving a global rise in pulmonary disease (MAC-PD) characterised by chronic infection, granulomatous inflammation and impaired respiratory function. Better animal models are needed to screen candidate therapies targeting bacteria and immune-mediated tissue injury. The C3HeB/FeJ mouse was previously reported to model necrotic granulomatous lung infection in MAC-PD following infection with a low-dose inoculum of the clinical isolate MAC2285R. We investigated whether this model was reproducible with variations in MAC strain and inoculating dose.</p><p><strong>Methods: </strong>Six-week-old female C3HeB/FeJ mice were infected intratracheally with a clinical isolate of MAC (MAC2285R) or reference strains (MAC104 or MAC101). Mice were culled at 4-weekly intervals post-infection until week 12. Lungs, spleen and liver were harvested for bacterial burden enumeration and histological examination. Whole body plethysmography (WBP) was performed weekly to measure changes in respiratory function (Buxco system).</p><p><strong>Results: </strong>C3HeB/FeJ mice infected with low dose inoculum of MAC2285R infection exhibited increasing bacterial lung infection for 8 weeks (<i>p</i> < 0.05), followed by stable lung burden from weeks 8-12. High dose inoculum resulted in stable lung bacterial burden over 12 weeks. Histological analysis revealed only mild inflammatory changes in both low and high dose inoculum groups at weeks 4, 8 and 12 post-infection, with no evidence of necrotising or non-necrotising granulomatous inflammation. Surrogate measures of respiratory effort (frequency, tidal volume, inspiratory and expiratory flow rates) were increased in mice with high dose inoculum compared to uninfected controls (<i>p</i> < 0.001), but not low dose inoculum. Similar findings on lung bacterial burden and histological analysis were found in mice infected with low- and high-dose inoculum of MAC104 and MAC101. MAC104 infection caused greater changes in respiratory function, whereas MAC101 did not significantly affect breathing patterns.</p><p><strong>Conclusion: </strong>The C3HeB/FeJ mouse is susceptible to chronic MAC infection from intratracheal infection with reference and clinical isolates, but this was not associated with severe granulomatous inflammation as previously reported. A low dose inoculum generated a proliferative lung infection, whereas high dose inoculum resulted in chronic, stable lung bacterial burden. Mice with high-dose inoculum MAC2285R and MAC104 infection also displayed evidence of increased respiratory effort.</p><p><strong>Supplementary information: </strong>The online version contains supplementary material available at 10.1186/s44350-025-00004-7.</p>","PeriodicalId":520521,"journal":{"name":"Mycobacteria (London, England)","volume":"1 1","pages":"4"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12081485/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144096742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishment of minimum protein standards for <i>Mycobacterium tuberculosis</i>-derived extracellular vesicles through comparison of EV enrichment methods.","authors":"Joan M Ryan, Kimberly Shelton, Monika Dzieciatkowska, Nicole Kruh-Garcia, Karen M Dobos","doi":"10.1186/s44350-025-00003-8","DOIUrl":"10.1186/s44350-025-00003-8","url":null,"abstract":"<p><p><i>Mycobacterium tuberculosis</i> extracellular vesicles (MEV) have been described as having potent immunological activities that are both beneficial and harmful to the host. Key to understanding this conflicting information is the proteomic characterization of MEVs. However, there is neither a standard for a purification method nor markers to assess relative purity and quality of MEVs. In this study, we purified MEVs by four different methods (simple ultracentrifugation, differential density gradient-based ultracentrifugation, qEV size exclusion chromatography, and Capto™Core size exclusion chromatography) and assessed the variability of MEV characteristics (size, concentration, appearance, purity, and protein content) amongst isolation methods. The vesicle appearance and size were consistent across all methods; however variability was found between and within all methods, with simple ultracentrifugation demonstrating the most variability both in reproducibility and purity. Protein concentration and content, and particle yield and purity, varied amongst all methods. The two size exclusion chromatography-based methods were more technically reproducible than either ultracentrifugation-based method, while qEV size exclusion chromatography and differential density gradient ultracentrifugation afforded MEV samples of the highest purity. Nonetheless, all methods had 7 proteins in common, the Sec-independent membrane bound twin-arginine translocase TatA (Rv2094c), the periplasmic phosphate-binding lipoprotein PstS3 (Rv0928), the heparin binding hemagglutinin HBHA (Rv0475), lipoprotein antigens LprG (Rv1411c) and LpqH (Rv3763), a member of the conserved 13E12 repeat protein family P95201 (Rv0393), and the tuberculin related peptide Rv0431 (P96277), suggesting the use of these proteins as qualitative markers of MEVs versus contaminants, in addition to size and appearance criteria, to benefit reproducibility and consensus for ongoing MEV studies.</p><p><strong>Supplementary information: </strong>The online version contains supplementary material available at 10.1186/s44350-025-00003-8.</p>","PeriodicalId":520521,"journal":{"name":"Mycobacteria (London, England)","volume":"1 1","pages":"3"},"PeriodicalIF":0.0,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12007408/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144056920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}