title: Deletion of the cyclic di-AMP phosphodiesterase gene (cnpB) in Mycobacterium tuberculosis leads to reduced virulence in a mouse model of infection.
abstract: Tuberculosis (TB) remains a major cause of morbidity and mortality worldwide. The pathogenesis by the causative agent, Mycobacterium tuberculosis, is still not fully understood. We have previously reported that M. tuberculosis Rv3586 (disA) encodes a diadenylate cyclase, which converts ATP to cyclic di-AMP (c-di-AMP). In this study, we demonstrated that a protein encoded by Rv2837c (cnpB) possesses c-di-AMP phosphodiesterase activity and cleaves c-di-AMP exclusively to AMP. Our results showed that in M. tuberculosis, deletion of disA abolished bacterial c-di-AMP production, whereas deletion of cnpB significantly enhanced the bacterial c-di-AMP accumulation and secretion. The c-di-AMP levels in both mutants could be corrected by expressing the respective gene. We also found that macrophages infected with ΔcnpB secreted much higher levels of IFN-β than those infected with the wild type (WT) or the complemented mutant. Interestingly, mice infected with M. tuberculosis ΔcnpB displayed significantly reduced inflammation, less bacterial burden in the lungs and spleens, and extended survival compared with those infected with the WT or the complemented mutant. These results indicate that deletion of cnpB results in attenuated virulence, which is correlated with elevated c-di-AMP levels.
authors.affiliation: Center for Immunology and Microbial Disease, MC-151, Albany Medical College, 47 New Scotland Avenue, Albany, NY, 12208-3479, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Yinlan
authors.initials: Y
authors.lastname: Bai
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Vincent D
authors.initials: VD
authors.lastname: Gabrielle
authors.forename: Lei
authors.initials: L
authors.lastname: Jin
authors.forename: Guangchun
authors.initials: G
authors.lastname: Bai
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015226:Dinucleoside Phosphates / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D008168:Lung / Q000382:microbiology; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009169:Mycobacterium tuberculosis / Q000201:enzymology / Q000472:pathogenicity*; D010727:Phosphoric Diester Hydrolases / Q000235:genetics* / Q000378:metabolism; D013154:Spleen / Q000382:microbiology; D014376:Tuberculosis / Q000382:microbiology* / Q000473:pathology; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D015226:Dinucleoside Phosphates; C528998:cyclic diadenosine phosphate; D010727:Phosphoric Diester Hydrolases