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Tatsuno I, Isaka M, Hasegawa T. Association of CovRS two-component regulatory system with NADase induction by Clindamycin treatment in Streptococcus pyogenes. Jpn J Infect Dis 2024:JJID.2023.451. [PMID: 38556301 DOI: 10.7883/yoken.jjid.2023.451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
The administration of high-dose clindamycin (CLI) along with penicillin is recommended for the treatment of streptococcal toxic shock syndrome (STSS). However, CLI-resistant strains have been identified worldwide. Firstly, in this study, some CLI-resistant strains showed increased extracellular activities of the NAD- glycohydrolase (NADase) exotoxin after CLI treatment. This result supported our previous conclusion that not only CLI-susceptible but also CLI-resistant S. pyogenes strains show the CLI-dependent NADase induction. Secondary, using the 13 types of two- component-sensor knockout strains derived from a CLI-susceptible strain 1529 that has the CLI-dependent NADase induction phenotype, we investigated the mechanism of action. Among the knockout strains, only 1529ΔcovS lost the phenotype. In addition, 1529ΔspeB, 1529Δmga, and 1529Δrgg retained the CLI-dependent NADase induction phenotype. These results suggest that CovS is related to the phenotype in SpeB independent manner.
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Affiliation(s)
- Ichiro Tatsuno
- Department of Bacteriology, Nagoya City University Graduate School of Medical Sciences, Japan
| | - Masanori Isaka
- Department of Bacteriology, Nagoya City University Graduate School of Medical Sciences, Japan
| | - Tadao Hasegawa
- Department of Bacteriology, Nagoya City University Graduate School of Medical Sciences, Japan
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2
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Schiavolin L, Deneubourg G, Steinmetz J, Smeesters PR, Botteaux A. Group A Streptococcus adaptation to diverse niches: lessons from transcriptomic studies. Crit Rev Microbiol 2024; 50:241-265. [PMID: 38140809 DOI: 10.1080/1040841x.2023.2294905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 12/10/2023] [Indexed: 12/24/2023]
Abstract
Group A Streptococcus (GAS) is a major human pathogen, causing diseases ranging from mild superficial infections of the skin and pharyngeal epithelium to severe systemic and invasive diseases. Moreover, post infection auto-immune sequelae arise by a yet not fully understood mechanism. The ability of GAS to cause a wide variety of infections is linked to the expression of a large set of virulence factors and their transcriptional regulation in response to various physiological environments. The use of transcriptomics, among others -omics technologies, in addition to traditional molecular methods, has led to a better understanding of GAS pathogenesis and host adaptation mechanisms. This review focusing on bacterial transcriptomic provides new insight into gene-expression patterns in vitro, ex vivo and in vivo with an emphasis on metabolic shifts, virulence genes expression and transcriptional regulators role.
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Affiliation(s)
- Lionel Schiavolin
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
| | - Geoffrey Deneubourg
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
| | - Jenny Steinmetz
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
| | - Pierre R Smeesters
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
- Department of Paediatrics, Brussels University Hospital, Academic Children Hospital Queen Fabiola, Université libre de Bruxelles, Brussels, Belgium
| | - Anne Botteaux
- Microbiology Laboratory, European Plotkin Institute of Vaccinology, Université libre de Bruxelles, Brussels, Belgium
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3
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DebRoy S, Shropshire WC, Vega L, Tran C, Horstmann N, Mukherjee P, Selvaraj-Anand S, Tran TT, Bremer J, Gohel M, Arias CA, Flores AR, Shelburne SA. Identification of distinct impacts of CovS inactivation on the transcriptome of acapsular group A streptococci. mSystems 2023; 8:e0022723. [PMID: 37358280 PMCID: PMC10470059 DOI: 10.1128/msystems.00227-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/11/2023] [Indexed: 06/27/2023] Open
Abstract
Group A streptococcal (GAS) strains causing severe, invasive infections often have mutations in the control of virulence two-component regulatory system (CovRS) which represses capsule production, and high-level capsule production is considered critical to the GAS hypervirulent phenotype. Additionally, based on studies in emm1 GAS, hyperencapsulation is thought to limit transmission of CovRS-mutated strains by reducing GAS adherence to mucosal surfaces. It has recently been identified that about 30% of invasive GAS strains lacks capsule, but there are limited data regarding the impact of CovS inactivation in such acapsular strains. Using publicly available complete genomes (n = 2,455) of invasive GAS strains, we identified similar rates of CovRS inactivation and limited evidence for transmission of CovRS-mutated isolates for both encapsulated and acapsular emm types. Relative to encapsulated GAS, CovS transcriptomes of the prevalent acapsular emm types emm28, emm87, and emm89 revealed unique impacts such as increased transcript levels of genes in the emm/mga region along with decreased transcript levels of pilus operon-encoding genes and the streptokinase-encoding gene ska. CovS inactivation in emm87 and emm89 strains, but not emm28, increased GAS survival in human blood. Moreover, CovS inactivation in acapsular GAS reduced adherence to host epithelial cells. These data suggest that the hypervirulence induced by CovS inactivation in acapsular GAS follows distinct pathways from the better studied encapsulated strains and that factors other than hyperencapsulation may account for the lack of transmission of CovRS-mutated strains. IMPORTANCE Devastating infections due to group A streptococci (GAS) tend to occur sporadically and are often caused by strains that contain mutations in the control of virulence regulatory system (CovRS). In well-studied emm1 GAS, the increased production of capsule induced by CovRS mutation is considered key to both hypervirulence and limited transmissibility by interfering with proteins that mediate attachment to eukaryotic cells. Herein, we show that the rates of covRS mutations and genetic clustering of CovRS-mutated isolates are independent of capsule status. Moreover, we found that CovS inactivation in multiple acapsular GAS emm types results in dramatically altered transcript levels of a diverse array of cell-surface protein-encoding genes and a unique transcriptome relative to encapsulated GAS. These data provide new insights into how a major human pathogen achieves hypervirulence and indicate that factors other than hyperencapsulation likely account for the sporadic nature of the severe GAS disease.
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Affiliation(s)
- Sruti DebRoy
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - William C. Shropshire
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Luis Vega
- Division of Infectious Diseases and Department of Pediatrics, McGovern Medical School at UTHealth Houston and Children’s Memorial Hermann Hospital, Houston, Texas, USA
| | - Chau Tran
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Nicola Horstmann
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Piyali Mukherjee
- Division of Infectious Diseases and Department of Pediatrics, McGovern Medical School at UTHealth Houston and Children’s Memorial Hermann Hospital, Houston, Texas, USA
| | | | - Truc T. Tran
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
- Division of Infectious Diseases, Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Jordan Bremer
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Marc Gohel
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Cesar A. Arias
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
- Division of Infectious Diseases, Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Anthony R. Flores
- Division of Infectious Diseases and Department of Pediatrics, McGovern Medical School at UTHealth Houston and Children’s Memorial Hermann Hospital, Houston, Texas, USA
| | - Samuel A. Shelburne
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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Chiang-Ni C, Chen YW, Chen KL, Jiang JX, Shi YA, Hsu CY, Chen YYM, Lai CH, Chiu CH. RopB represses the transcription of speB in the absence of SIP in group A Streptococcus. Life Sci Alliance 2023; 6:e202201809. [PMID: 37001914 PMCID: PMC10071013 DOI: 10.26508/lsa.202201809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/23/2023] [Accepted: 03/23/2023] [Indexed: 04/03/2023] Open
Abstract
RopB is a quorum-sensing regulator that binds to the SpeB-inducing peptide (SIP) under acidic conditions. SIP is known to be degraded by the endopeptidase PepO, whose transcription is repressed by the CovR/CovS two-component regulatory system. Both SIP-bound RopB (RopB-SIP) and SIP-free RopB (apo-RopB) can bind to the speB promoter; however, only RopB-SIP activates speB transcription. In this study, we found that the SpeB expression was higher in the ropB mutant than in the SIP-inactivated (SIP*) mutant. Furthermore, the deletion of ropB in the SIP* mutant derepressed speB expression, suggesting that apo-RopB is a transcriptional repressor of speB Up-regulation of PepO in the covS mutant degraded SIP, resulting in the down-regulation of speB We demonstrate that deleting ropB in the covS mutant derepressed the speB expression, suggesting that the speB repression in this mutant was mediated not only by PepO-dependent SIP degradation but also by apo-RopB. These findings reveal a crosstalk between the CovR/CovS and RopB-SIP systems and redefine the role of RopB in regulating speB expression in group A Streptococcus.
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Affiliation(s)
- Chuan Chiang-Ni
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Yan-Wen Chen
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kai-Lin Chen
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Jian-Xian Jiang
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yong-An Shi
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Yun Hsu
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Ywan M Chen
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Chih-Ho Lai
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Cheng-Hsun Chiu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
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Chang CH, Lee SH, Lin YC, Hsu CY, Cheng CC, Teng SH, Chen MF, Hsieh PH, Chang Y, Chiang-Ni C. Characterization of the phenotypes of methicillin- and vancomycin-susceptible Staphylococcus argenteus after vancomycin passages. J Glob Antimicrob Resist 2022; 31:63-71. [PMID: 35964863 DOI: 10.1016/j.jgar.2022.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/02/2022] [Accepted: 08/08/2022] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVES Staphylococcus argenteus is generally more susceptible to antibiotic treatments than Staphylococcus aureus; however, the study showed that the daptomycin/vancomycin-resistant S. argenteus was isolated from a patient with repeated antibiotic treatments. In this study, the methicillin- and vancomycin-susceptible S. argenteus isolates were used to characterize the phenotypes of S. argenteus after vancomycin passages in vitro. METHODS Eleven S. argenteus isolates were used for passaging under different concentrations of vancomycin. The minimal inhibitory concentration (MIC) of vancomycin was determined by the agar dilution assay, and the biofilm mass of the passaged variants was quantified by the crystal violet staining assay and observed under the confocal microscope. RESULTS The MIC of vancomycin for eight of 11 S. argenteus isolates was increased from ≤2 µg/mL to ≤4-8 µg/mL after vancomycin passages. Two variants with the high-level vancomycin-intermediate (vancomycin MIC ≤8 µg/mL) phenotype were identified, and the parental strains of these variants did not have the heterogeneous vancomycin-intermediate population determined by the population profile analysis. Further, three S. argenteus isolates showed an increase in biofilm production and icaA transcription after the low-dose (2 µg/mL) vancomycin passages. CONCLUSIONS S. argenteus is capable of acquiring a vancomycin-tolerant phenotype and/or converting to a strong biofilm producer after vancomycin passages, which could contribute to the decrease of their antibiotic susceptibility.
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Affiliation(s)
- Chih-Hsiang Chang
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Bone and Joint Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Sheng-Hsun Lee
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Bone and Joint Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Chih Lin
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Bone and Joint Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Yun Hsu
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Chieh Cheng
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shih-Hua Teng
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Mei-Feng Chen
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Bone and Joint Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Pang-Hsin Hsieh
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Bone and Joint Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yuhan Chang
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Bone and Joint Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Chuan Chiang-Ni
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
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6
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Abstract
Necrotizing fasciitis is a severe infectious disease that results in significant mortality. Streptococcus pyogenes (group A Streptococcus, GAS) is one of the most common bacterial pathogens of monomicrobial necrotizing fasciitis. The early diagnosis of necrotizing fasciitis is crucial; however, the typical cutaneous manifestations are not always presented in patients with GAS necrotizing fasciitis, which would lead to miss- or delayed diagnosis. GAS with spontaneous inactivating mutations in the CovR/CovS two-component regulatory system is significantly associated with destructive diseases such as necrotizing fasciitis and toxic shock syndrome; however, no specific marker has been used to identify these invasive clinical isolates. This study evaluated the sensitivity and specificity of using CovR/CovS-controlled phenotypes to identify CovR/CovS-inactivated isolates. Results showed that the increase of hyaluronic acid capsule production and streptolysin O expression were not consistently presented in CovS-inactivated clinical isolates. The repression of SpeB is the phenotype with 100% sensitivity of identifying in CovS-inactivated isolates among 61 clinical isolates. Nonetheless, this phenotype failed to distinguish RopB-inactivated isolates from CovS-inactivated isolates and cannot be utilized to identify CovR-inactivated mutant and RocA (Regulator of Cov)-inactivated isolates. In this study, we identified and verified that PepO, the endopeptidase which regulates SpeB expression through degrading SpeB-inducing quorum-sensing peptide, was a bacterial marker to identify isolates with defects in the CovR/CovS pathway. These results also inform the potential strategy of developing rapid detection methods to identify invasive GAS variants during infection. IMPORTANCE Necrotizing fasciitis is rapidly progressive and life-threatening; if the initial diagnosis is delayed, deep soft tissue infection can progress to massive tissue destruction and toxic shock syndrome. Group A Streptococcus (GAS) with inactivated mutations in the CovR/CovS two-component regulatory system are related to necrotizing fasciitis and toxic shock syndrome; however, no bacterial marker is available to identify these invasive clinical isolates. Inactivation of CovR/CovS resulted in the increased expression of endopeptidase PepO. Our study showed that the upregulation of PepO mediates a decrease in SpeB-inducing peptide (SIP) in the covR mutant, indicating that CovR/CovS modulates SIP-dependent quorum-sensing activity through PepO. Importantly, the sensitivity and specificity of utilizing PepO to identify clinical isolates with defects in the CovR/CovS pathway, including its upstream RocA regulator, were 100%. Our results suggest that identification of invasive GAS by PepO may be a strategy for preventing severe manifestation or poor prognosis after GAS infection.
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The CovRS Environmental Sensor Directly Controls the ComRS Signaling System To Orchestrate Competence Bimodality in Salivarius Streptococci. mBio 2022; 13:e0312521. [PMID: 35089064 PMCID: PMC8725580 DOI: 10.1128/mbio.03125-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In bacteria, phenotypic heterogeneity in an isogenic population compensates for the lack of genetic diversity and allows concomitant multiple survival strategies when choosing only one is too risky. This powerful tactic is exploited for competence development in streptococci where only a subset of the community triggers the pheromone signaling system ComR-ComS, resulting in a bimodal activation. However, the regulatory cascade and the underlying mechanisms of this puzzling behavior remained partially understood. Here, we show that CovRS, a well-described virulence regulatory system in pathogenic streptococci, directly controls the ComRS system to generate bimodality in the gut commensal Streptococcus salivarius and the closely related species Streptococcus thermophilus. Using single-cell analysis of fluorescent reporter strains together with regulatory mutants, we revealed that the intracellular concentration of ComR determines the proportion of competent cells in the population. We also showed that this bimodal activation requires a functional positive-feedback loop acting on ComS production, as well as its exportation and reinternalization via dedicated permeases. As the intracellular ComR concentration is critical in this process, we hypothesized that an environmental sensor could control its abundance. We systematically inactivated all two-component systems and identified CovRS as a direct repression system of comR expression. Notably, we showed that the system transduces its negative regulation through CovR binding to multiple sites in the comR promoter region. Since CovRS integrates environmental stimuli, we suggest that it is the missing piece of the puzzle that connects environmental conditions to (bimodal) competence activation in salivarius streptococci. IMPORTANCE Combining production of antibacterial compounds and uptake of DNA material released by dead cells, competence is one of the most efficient survival strategies in streptococci. Yet, this powerful tactic is energy consuming and reprograms the metabolism to such an extent that cell proliferation is transiently impaired. To circumvent this drawback, competence activation is restricted to a subpopulation, a process known as bimodality. In this work, we explored this phenomenon in salivarius streptococci and elucidated the molecular mechanisms governing cell fate. We also show that an environmental sensor controlling virulence in pathogenic streptococci is diverted to control competence in commensal streptococci. Together, those results showcase how bacteria can sense and transmit external stimuli to complex communication devices for fine-tuning collective behaviors.
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8
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Acetylation of glucosyltransferases regulates Streptococcus mutans biofilm formation and virulence. PLoS Pathog 2021; 17:e1010134. [PMID: 34860858 PMCID: PMC8673623 DOI: 10.1371/journal.ppat.1010134] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Revised: 12/15/2021] [Accepted: 11/19/2021] [Indexed: 02/05/2023] Open
Abstract
Lysine acetylation is a frequently occurring post-translational modification (PTM), emerging as an important metabolic regulatory mechanism in prokaryotes. This process is achieved enzymatically by the protein acetyltransferase (KAT) to specifically transfer the acetyl group, or non-enzymatically by direct intermediates (acetyl phosphate or acetyl-CoA). Although lysine acetylation modification of glucosyltransferases (Gtfs), the important virulence factor in Streptococcus mutans, was reported in our previous study, the KAT has not been identified. Here, we believe that the KAT ActG can acetylate Gtfs in the enzymatic mechanism. By overexpressing 15 KATs in S. mutans, the synthesized water-insoluble extracellular polysaccharides (EPS) and biofilm biomass were measured, and KAT (actG) was identified. The in-frame deletion mutant of actG was constructed to validate the function of actG. The results showed that actG could negatively regulate the water-insoluble EPS synthesis and biofilm formation. We used mass spectrometry (MS) to identify GtfB and GtfC as the possible substrates of ActG. This was also demonstrated by in vitro acetylation assays, indicating that ActG could increase the acetylation levels of GtfB and GtfC enzymatically and decrease their activities. We further found that the expression level of actG in part explained the virulence differences in clinically isolated strains. Moreover, overexpression of actG in S. mutans attenuated its cariogenicity in the rat caries model. Taken together, our study demonstrated that the KAT ActG could induce the acetylation of GtfB and GtfC enzymatically in S. mutans, providing insights into the function of lysine acetylation in bacterial virulence and pathogenicity. Lysine acetylation is a regulatory post-translational modification (PTM) important in physiological processes across all domains of life. Although it has been well studied and characterized in eukaryotes, new insights into the lysine acetylation in bacteria have gained momentum in recent years, and hundreds to thousands of protein acetylation processes have been identified in various bacteria with novel enrichment strategies. However, the specific mechanisms of regulating lysine acetylation and function are still poorly understood. Therefore, we screened for the KAT mediating Gtfs acetylation by constructing 15 strains of S. mutans that overexpressed the GCN5-related N-acetyltransferases (GNAT) family members. Eventually, we identified and characterized ActG, a GNAT family member, that could catalyze the acetylation of GtfB and GtfC in S. mutans by the enzymatic mechanism, inversely related to their enzymatic activities, subsequently affecting the water-insoluble EPS synthesis and biofilm formation. In addition, ActG impaired the cariogenicity of S. mutans in a rat caries model. Thus, this study provides significant insights into the effect of lysine acetylation on S. mutans virulence and pathogenicity by regulating target protein functions and relative physiological processes.
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9
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Chiang-Ni C, Liu YS, Lin CY, Hsu CY, Shi YA, Chen YYM, Lai CH, Chiu CH. Incidence and Effects of Acquisition of the Phage-Encoded ssa Superantigen Gene in Invasive Group A Streptococcus. Front Microbiol 2021; 12:685343. [PMID: 34149675 PMCID: PMC8212969 DOI: 10.3389/fmicb.2021.685343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/12/2021] [Indexed: 11/13/2022] Open
Abstract
The acquisition of the phage-encoded superantigen ssa by scarlet fever-associated group A Streptococcus (Streptococcus pyogenes, GAS) is found in North Asia. Nonetheless, the impact of acquiring ssa by GAS in invasive infections is unclear. This study initially analyzed the prevalence of ssa+ GAS among isolates from sterile tissues and blood. Among 220 isolates in northern Taiwan, the prevalence of ssa+ isolates increased from 1.5% in 2008–2010 to 40% in 2017–2019. Spontaneous mutations in covR/covS, which result in the functional loss of capacity to phosphorylate CovR, are frequently recovered from GAS invasive infection cases. Consistent with this, Phostag western blot results indicated that among the invasive infection isolates studied, 10% of the ssa+ isolates lacked detectable phosphorylated CovR. Transcription of ssa is upregulated in the covS mutant. Furthermore, in emm1 and emm12 covS mutants, ssa deletion significantly reduced their capacity to grow in human whole blood. Finally, this study showed that the ssa gene could be transferred from emm12-type isolates to the emm1-type wild-type strain and covS mutants through phage infection and lysogenic conversion. As the prevalence of ssa+ isolates increased significantly, the role of streptococcal superantigen in GAS pathogenesis, particularly in invasive covR/covS mutants, should be further analyzed.
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Affiliation(s)
- Chuan Chiang-Ni
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan.,Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Yen-Shan Liu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chieh-Yu Lin
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chih-Yun Hsu
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yong-An Shi
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Ywan M Chen
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Chih-Ho Lai
- Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Cheng-Hsun Chiu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.,Molecular Infectious Disease Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan.,Division of Pediatric Infectious Diseases, Department of Pediatrics, Chang Gung Memorial Hospital, Linkou, Taiwan
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10
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The upcycled roles of pseudoenzymes in two-component signal transduction. Curr Opin Microbiol 2021; 61:82-90. [PMID: 33872991 DOI: 10.1016/j.mib.2021.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 11/23/2022]
Abstract
Upon first glance at a bacterial genome, pseudoenzymes appear unremarkable due to their lack of critical motifs that facilitate catalysis. These pseudoenzymes exist within signal transduction enzymes including histidine kinases, response regulators, diguanylate cyclases, and phosphodiesterases. Here, we summarize recent studies of bacterial pseudo-histidine kinases and pseudo-response regulators that regulate cell division, capsule formation, and the circadian rhythm. These examples illuminate the mechanistic potential of catalytically dead signaling enzymes and their impact upon bacterial signal transduction. Moreover, proteins lacking characteristic catalytic features of two-component systems reveal the sophisticated underlying potential of canonical two-component systems.
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11
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Single Amino Acid Replacements in RocA Disrupt Protein-Protein Interactions To Alter the Molecular Pathogenesis of Group A Streptococcus. Infect Immun 2020; 88:IAI.00386-20. [PMID: 32817331 DOI: 10.1128/iai.00386-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/12/2020] [Indexed: 12/31/2022] Open
Abstract
Group A Streptococcus (GAS) is a human-specific pathogen and major cause of disease worldwide. The molecular pathogenesis of GAS, like many pathogens, is dependent on the coordinated expression of genes encoding different virulence factors. The control of virulence regulator/sensor (CovRS) two-component system is a major virulence regulator of GAS that has been extensively studied. More recent investigations have also involved regulator of Cov (RocA), a regulatory accessory protein to CovRS. RocA interacts, in some manner, with CovRS; however, the precise molecular mechanism is unknown. Here, we demonstrate that RocA is a membrane protein containing seven transmembrane helices with an extracytoplasmically located N terminus and cytoplasmically located C terminus. For the first time, we demonstrate that RocA directly interacts with itself (RocA) and CovS, but not CovR, in intact cells. Single amino acid replacements along the entire length of RocA disrupt RocA-RocA and RocA-CovS interactions to significantly alter the GAS virulence phenotype as defined by secreted virulence factor activity in vitro and tissue destruction and mortality in vivo In summary, we show that single amino acid replacements in a regulatory accessory protein can affect protein-protein interactions to significantly alter the virulence of a major human pathogen.
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