Tumor suppressor CYLD regulates acute lung injury in lethal Streptococcus pneumoniae infections.
Lim Jae Hyang,Stirling Brigid,Derry Jonathan,Koga Tomoaki,Jono Hirofumi,Woo Chang-Hoon,Xu Haodong,Bourne Patricia,Ha Un-Hwan,Ishinaga Hajime,Xu Haidong,Andalibi Ali,Feng Xin-Hua,Zhu Hongguang,Huang Yuxian,Zhang Wenhong,Weng Xinhua,Yan Chen,Yin Zhinan,Briles David E,Davis Roger J,Flavell Richard A,Li Jian-Dong
Streptococcus pneumoniae (S. pneumoniae) causes high early mortality in pneumococcal pneumonia, which is characterized by acute lung injury (ALI). The molecular mechanisms underlying ALI and the high early mortality remain unknown. Despite recent studies that identify deubiquitinating enzyme cylindromatosis (CYLD) as a key regulator for T cell development, tumor cell proliferation, and NF-kappaB transcription factor signaling, its role in regulating bacteria-induced lethality, however, is unknown. Here, we showed that CYLD deficiency protected mice from S. pneumoniae pneumolysin (PLY)-induced ALI and lethality. CYLD was highly induced by PLY, and it inhibited MKK3-p38 kinase-dependent expression of plasminogen activator inhibitor-1 (PAI-1) in lung, thereby potentiating ALI and mortality. Thus, CYLD is detrimental for host survival, thereby indicating a mechanism underlying the high early mortality of pneumococcal pneumonia.
Ranking of persister genes in the same Escherichia coli genetic background demonstrates varying importance of individual persister genes in tolerance to different antibiotics.
Wu Nan,He Lei,Cui Peng,Wang Wenjie,Yuan Youhua,Liu Shuang,Xu Tao,Zhang Shanshan,Wu Jing,Zhang Wenhong,Zhang Ying
Frontiers in microbiology
Despite the identification of many genes and pathways involved in the persistence phenomenon of bacteria, the relative importance of these genes in a single organism remains unclear. Here, using Escherichia coli as a model, we generated mutants of 21 known candidate persister genes and compared the relative importance of these mutants in persistence to various antibiotics (ampicillin, gentamicin, norfloxacin, and trimethoprim) at different times. We found that oxyR, dnaK, sucB, relA, rpoS, clpB, mqsR, and recA were prominent persister genes involved in persistence to multiple antibiotics. These genes map to the following pathways: antioxidative defense pathway (oxyR), global regulators (dnaK, clpB, and rpoS), energy production (sucB), stringent response (relA), toxin-antitoxin (TA) module (mqsR), and SOS response (recA). Among the TA modules, the ranking order was mqsR, lon, relE, tisAB, hipA, and dinJ. Intriguingly, rpoS deletion caused a defect in persistence to gentamicin but increased persistence to ampicillin and norfloxacin. Mutants demonstrated dramatic differences in persistence to different antibiotics at different time points: some mutants (oxyR, dnaK, phoU, lon, recA, mqsR, and tisAB) displayed defect in persistence from early time points, while other mutants (relE, smpB, glpD, umuD, and tnaA) showed defect only at later time points. These results indicate that varying hierarchy and importance of persister genes exist and that persister genes can be divided into those involved in shallow persistence and those involved in deep persistence. Our findings suggest that the persistence phenomenon is a dynamic process with different persister genes playing roles of variable significance at different times. These findings have implications for improved understanding of persistence phenomenon and developing new drugs targeting persisters for more effective cure of persistent infections.
Disruption of Membrane by Colistin Kills Uropathogenic Escherichia coli Persisters and Enhances Killing of Other Antibiotics.
Cui Peng,Niu Hongxia,Shi Wanliang,Zhang Shuo,Zhang Hao,Margolick Joseph,Zhang Wenhong,Zhang Ying
Antimicrobial agents and chemotherapy
Persisters are small populations of quiescent bacterial cells that survive exposure to bactericidal antibiotics and are responsible for many persistent infections and posttreatment relapses. However, little is known about how to effectively kill persister bacteria. In the work presented here, we found that colistin, a membrane-active antibiotic, was highly active against Escherichia coli persisters at high concentrations (25 or 50 μg/ml). At a clinically relevant lower concentration (10 μg/ml), colistin alone had no apparent effect on E. coli persisters. In combination with other drugs, this concentration of colistin enhanced the antipersister activity of gentamicin and ofloxacin but not that of ampicillin, nitrofurans, and sulfa drugs in vitro The colistin enhancement effect was most likely due to increased uptake of the other antibiotics, as demonstrated by increased accumulation of fluorescence-labeled gentamicin. Interestingly, colistin significantly enhanced the activity of ofloxacin and nitrofurantoin but not that of gentamicin or sulfa drugs in the murine model of urinary tract infection. Our findings suggest that targeting bacterial membranes is a valuable approach to eradicating persisters and should have implications for more effective treatment of persistent bacterial infections.
Identification of Genes Involved in Bacteriostatic Antibiotic-Induced Persister Formation.
Cui Peng,Niu Hongxia,Shi Wanliang,Zhang Shuo,Zhang Wenhong,Zhang Ying
Frontiers in microbiology
Persister cells are metabolically quiescent multi-drug tolerant fraction of a genetically sensitive bacterial population and are thought to be responsible for relapse of many persistent infections. Persisters can be formed naturally in the stationary phase culture, and also can be induced by bacteriostatic antibiotics. However, the molecular basis of bacteriostatic antibiotic induced persister formation is unknown. Here, we established a bacteriostatic antibiotic induced persister model and screened the single gene deletion mutant library for mutants with defect in rifampin or tetracycline induced persistence to ofloxacin. Thirsty-seven and nine genes were found with defects in rifampin- and tetracycline-induced persister formation, respectively. Six mutants were found to overlap in both rifampin and tetracycline induced persister screens: , , , , , and . Interestingly, four of these mutants (, , and ) mapped to DNA repair pathway, one mutant mapped to global transcriptional regulator () and one to efflux (). The stationary phase culture of the identified mutants and parent strain BW25113 were subjected to different antibiotics including ofloxacin, ampicillin, gentamicin, and stress conditions including starvation and acid pH 4.0. All the six mutants showed less tolerance to ofloxacin, but only some of them were more sensitive to other specific stress conditions. Complementation of five of the six common mutants restored the persister level to that of the parent strain in both stationary phase and static antibiotic-induced conditions. In addition to the DNA repair pathways shared by both rifampin and tetracycline induced persisters, genes involved in rifampin-induced persisters map also to transporters, LPS biosynthesis, flagella biosynthesis, metabolism (folate and energy), and translation, etc. These findings suggest that persisters generated by different ways may share common mechanisms of survival, and also shed new insight into the molecular basis of static antibiotic induced antagonism of cidal antibiotics.
Magnesium Links Starvation-Mediated Antibiotic Persistence to ATP.
Xu Tao,Wang Xuyang,Meng Lu,Zhu Mengqi,Wu Jing,Xu Yuanyuan,Zhang Ying,Zhang Wenhong
Bacterial persisters emerge and increase in numbers over time as a bacterial culture grows from log phase to stationary phase. However, the underlying basis of the inevitable tendency is unclear. In this study, we investigated the role of nutrients in starvation-mediated persister formation of By screening of nutrient components, we found that starvation-induced persister formation of log-phase cultures could be reversed by addition of magnesium (Mg) but not amino acids, nucleotides, or other salts. Further, deprivation of extracellular Mg reduced cytoplasmic ATP, inducing persistence without affecting cytoplasmic Mg or membrane potential. Finally, we showed that Mg reduced expression of stationary cell marker genes, and These findings indicate a connection between Mg levels and ATP, which represents metabolic status and mediates antibiotic persistence during growth. Various genes have been identified to be involved in bacterial persister formation regardless of the presence or absence of persister genes. Despite recent discoveries of the roles of ATP and membrane potential in persister formation, the key element that triggers change of ATP or membrane potential remains elusive. Our work demonstrates that Mg instead of other ions or nutrient components is the key element for persistence by inducing a decrease of cytoplasmic ATP, which subsequently induces persister formation. In addition, we observed tight regulation of genes for Mg transport in different growth phases in These findings indicate that despite being a key nutrient, Mg also served as a key signal in persister formation during growth.