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Subsomwong P, Teng W, Ishiai T, Narita K, Sukchawalit R, Nakane A, Asano K. Extracellular vesicles from Staphylococcus aureus promote the pathogenicity of Pseudomonas aeruginosa. Microbiol Res 2024; 281:127612. [PMID: 38244256 DOI: 10.1016/j.micres.2024.127612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/26/2023] [Accepted: 01/09/2024] [Indexed: 01/22/2024]
Abstract
Co-infections with Staphylococcus aureus and Pseudomonas aeruginosa are common in patients with chronic wounds, but little is known about their synergistic effect mediated by extracellular vesicles (EVs). In this study, we investigated the effect of EVs derived from S. aureus (SaEVs) on the pathogenicity of P. aeruginosa. By using lipophilic dye, we could confirm the fusion between SaEV and P. aeruginosa membranes. However, SaEVs did not alter the growth and antibiotic susceptible pattern of P. aeruginosa. Differential proteomic analysis between SaEV-treated and non-treated P. aeruginosa was performed, and the results revealed that lipopolysaccharide (LPS) biosynthesis protein in P. aeruginosa significantly increased after SaEV-treatment. Regarding this result, we also found that SaEVs promoted LPS production, biofilm formation, and expression of polysaccharide polymerization-related genes in P. aeruginosa. Furthermore, invasion of epithelial cells by SaEV-pretreated P. aeruginosa was enhanced. On the other hand, uptake of P. aeruginosa by RAW 264.7 macrophages was impaired after pretreatment P. aeruginosa with SaEVs. Proteomic analysis SaEVs revealed that SaEVs contain the proteins involving in host cell colonization, inhibition of host immune response, anti-phagocytosis of the macrophages, and protein translocation and iron uptake of S. aureus. In conclusion, SaEVs serve as a mediator that promote P. aeruginosa pathogenicity by enhancing LPS biosynthesis, biofilm formation, epithelial cell invasion, and macrophage uptake impairment.
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Affiliation(s)
- Phawinee Subsomwong
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Wei Teng
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Takahito Ishiai
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Kouji Narita
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan; Institute for Animal Experimentation, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Rojana Sukchawalit
- Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok, Thailand
| | - Akio Nakane
- Department of Biopolymer and Health Science, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Krisana Asano
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan; Department of Biopolymer and Health Science, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
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Li Y, Jv M, Zhuang Y, Zhao X, Hu X. A hypervirulent Acinetobacter baumannii strain has robust anti-phagocytosis ability. BMC Microbiol 2024; 24:106. [PMID: 38561652 PMCID: PMC10983618 DOI: 10.1186/s12866-024-03264-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 03/17/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Acinetobacter baumannii (A. baumannii) is associated with both hospital-acquired infections (HAP) and community-acquired pneumonia (CAP). In this study, we present a novel CAP-associated A. baumannii (CAP-AB) strain causing severe pneumonia in an afore healthy male patient without underlying conditions. Subsequently, we investigated the pathogenicity and immunogenicity of this CAP-AB strain using a mice pneumonia model. RESULTS A 58-year-old male patient with no underlying conditions experienced worsening symptoms of a productive cough, sputum, and fever that developed acutely, in just 24 h. The diagnosis was severe community-acquired pneumonia (CAP) and type-1 respiratory failure. An A. baumannii strain was isolated from his sputum and blood cultures. To gain a deeper understanding of the rapid progression of its pathology, we utilized the CAP-associated A. baumannii strain YC128, a previously obtained hospital-acquired pneumonia A. baumannii (HAP-AB) strain YC156, and a highly virulent A. baumannii control strain LAC-4 to construct a mouse pneumonia model, and subsequently compared the mortality rate of the three groups. Following inoculation with 107 CFU of A. baumannii, the mortality rate for the YC128, LAC-4, and YC156 groups was 60% (6/10), 30% (3/10), and 0%, respectively. The bacterial burden within the pulmonary, liver, and spleen tissues of mice in the YC128 group was significantly higher than that of the YC156 group, and slightly higher than that of the LAC-4 group. Pathological analysis of lung tissue using HE-staining revealed that the inflammatory pathological changes in mice from the YC128 group were significantly more severe than those in the YC156 group. Additionally, CT scan images displayed more pronounced inflammation in the lungs of mice from the YC128 group compared to the YC156 group. Local levels of cytokines/chemokines such as IL-1β, IL-6, TNF-α, and CXCL1 were assessed via RT-qPCR in lung tissues. In comparison with the YC156 strain, the highly virulent YC128 strain induced the expression of proinflammatory cytokines more rapidly and severely. Furthermore, we examined the in vitro anti-phagocytosis ability of YC128 and YC156 strains against mice peritoneal macrophages, revealing that the highly virulent YC128 isolate displayed greater resistance to macrophage uptake in contrast to YC156. Results from Whole Genome Sequencing (WGS) indicated that YC128 harbored a complete type VI secretion system (T6SS) gene cluster, while YC156 lacked the majority of genes within the T6SS gene cluster. The other virulence-related genes exhibited minimal differences between YC128 and YC156. Drawing from previous studies, we postulated that the T6SS is linked to the hypervirulence and robust anti-phagocytic ability of YC128. CONCLUSIONS This article reports on the isolation of a novel hypervirulent CAP-AB strain, YC128, from a severe CAP patient. The results demonstrate that this CAP-AB strain, YC128, is capable of inducing fatal pneumonia and extrapulmonary dissemination in a mouse pneumonia model. Moreover, this highly virulent CAP-AB strain exhibits significantly stronger anti-phagocytic abilities compared to the HAP-AB YC156 strain. Genome sequencing comparisons reveal that the heightened hypervirulence and enhanced anti-phagocytosis abilities observed in YC128 may be attributed to the presence of the T6SS.
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Affiliation(s)
- Yan Li
- Division of Infectious Diseases, Yichun People's Hospital, Yichun, Jiangxi Province, China
| | - Mohan Jv
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Yuan Zhuang
- Department of Infectious Diseases, People's Hospital of Rizhao, Ri Zhao, Shandong Province, China
| | - Xu Zhao
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.
- Department of Infectious Diseases, Huashan Hospital Fujian Campus, Fudan University, Fuzhou, Fujian Province, China.
| | - Xiaoxiong Hu
- Division of Infectious Diseases, Yichun People's Hospital, Yichun, Jiangxi Province, China.
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Gong L, Tian L, Cui K, Chen Y, Liu B, Li D, Feng Y, Yao S, Yin Y, Wu Z, Huang Z. An off-the-shelf small extracellular vesicle nanomedicine for tumor targeting therapy. J Control Release 2023; 364:672-686. [PMID: 37967724 DOI: 10.1016/j.jconrel.2023.11.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 11/02/2023] [Accepted: 11/08/2023] [Indexed: 11/17/2023]
Abstract
Small extracellular vesicles (sEVs) have shown excellent prospects as drug delivery systems for cancer therapy. However, the inherent non-targeting and short blood circulation characteristics severely restrict their practical applications as a delivery system. In addition, post-encapsulating drugs into sEVs also remains challenging. Here, we constructed an engineered cell line that secreted multifunctional sEVs (termed NBsEV204) with 7D12 (an anti-EGFR nanobody) and hCD47 decorations on their surface, as well as high levels of miR-204-5p encapsulation. NBsEV204 exhibited extended blood circulation and improved macrophage-mediated phagocytosis of tumor cells by blocking CD47 signaling. Importantly, NBsEV204 specifically targeted EGFR+ tumor cells and showed robust tumor-suppressive effects both in vitro and in vivo. Overall, this study provides a convenient and feasible method to produce off-the-shelf anticancer sEV nanomedicine, which exhibits tremendous potential for clinical translation.
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Affiliation(s)
- Liang Gong
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, 214062 Wuxi, People's Republic of China; Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122 Wuxi, People's Republic of China; Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Lu Tian
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, 214062 Wuxi, People's Republic of China; Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Kaisa Cui
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, 214062 Wuxi, People's Republic of China; Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Ying Chen
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, 214062 Wuxi, People's Republic of China; Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Bingxin Liu
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, 214062 Wuxi, People's Republic of China; Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Dan Li
- Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Yuyang Feng
- Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Surui Yao
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, 214062 Wuxi, People's Republic of China; Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Yuan Yin
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, 214062 Wuxi, People's Republic of China; Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Zhimeng Wu
- Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122 Wuxi, People's Republic of China.
| | - Zhaohui Huang
- Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, 214062 Wuxi, People's Republic of China; Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, 214122 Wuxi, People's Republic of China.
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Zhao C, Jia X, Pan Y, Liao S, Zhang S, Ji C, Kuang G, Wu X, Liu Q, Tang Y, Fang L. Thioredoxin A of Streptococcus suis Serotype 2 Contributes to Virulence by Inhibiting the Expression of Pentraxin 3 to Promote Survival Within Macrophages. J Microbiol 2023; 61:433-448. [PMID: 37010796 DOI: 10.1007/s12275-023-00038-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 02/27/2023] [Accepted: 03/06/2023] [Indexed: 04/04/2023]
Abstract
Streptococcus suis serotype 2 (SS2) is an important zoonotic pathogen that can infect humans in contact with infected pigs or their byproducts. It can employ different types of genes to defend against oxidative stress and ensure its survival. The thioredoxin (Trx) system is a key antioxidant system that contributes adversity adaptation and pathogenicity. SS2 has been shown to encode putative thioredoxin genes, but the biological roles, coding sequence, and underlying mechanisms remains uncharacterized. Here, we demonstrated that SSU05_0237-ORF, from a clinical SS2 strain, ZJ081101, encodes a protein of 104 amino acids with a canonical CGPC active motif and an identity 70-85% similar to the thioredoxin A (TrxA) in other microorganisms. Recombinant TrxA efficiently catalyzed the thiol-disulfide oxidoreduction of insulin. The deletion of TrxA led to a significantly slow growth and markedly compromised tolerance of the pathogen to temperature stress, as well as impaired adhesion ability to pig intestinal epithelial cells (IPEC-J2). However, it was not involved in H2O2 and paraquat-induced oxidative stress. Compared with the wild-type strain, the ΔTrxA strain was more susceptible to killing by macrophages through increasing NO production. Treatment with TrxA mutant strain also significantly attenuated cytotoxic effects on RAW 264.7 cells by inhibiting inflammatory response and apoptosis. Knockdown of pentraxin 3 in RAW 264.7 cells was more vulnerable to phagocytic activity, and TrxA promoted SS2 survival in phagocytic cells depending on pentraxin 3 activity compared with the wild-type strain. Moreover, a co-inoculation experiment in mice revealed that TrxA mutant strain is far more easily cleared from the body than the wild type strain in the period from 8-24 h, and exhibits significantly attenuated oxidative stress and liver injury. In summary, we reveal the important role of TrxA in the pathogenesis of SS2.
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Affiliation(s)
- Chijun Zhao
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410125, China
| | - Xinglin Jia
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410125, China
| | - Yanying Pan
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410125, China
| | - Simeng Liao
- Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China
| | - Shuo Zhang
- Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China
- South Southwest Agriculture and Animal Husbandry Group, Ltd, Kunming, 650217, China
| | - Chunxiao Ji
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410125, China
| | - Guangwei Kuang
- Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China
| | - Xin Wu
- Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China
| | - Quan Liu
- School of Life Science and Engineering, Foshan University, Foshan, 528225, Guangdong, China
| | - Yulong Tang
- Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
- Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Hefei, 230001, China.
| | - Lihua Fang
- School of Life Science and Engineering, Foshan University, Foshan, 528225, Guangdong, China.
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Hui X, Xu Z, Cao L, Liu L, Lin X, Yang Y, Sun X, Zhang Q, Jin M. HP0487 contributes to the virulence of Streptococcus suis serotype 2 by mediating bacterial adhesion and anti-phagocytosis to neutrophils. Vet Microbiol 2021; 260:109164. [PMID: 34247113 DOI: 10.1016/j.vetmic.2021.109164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 06/17/2021] [Indexed: 01/15/2023]
Abstract
Streptococcus suis serotype 2 (SS2) is an important zoonotic pathogen that poses a serious threat to human health and the swine industry. The survival and travel in the bloodstream are the important causes for SS2, contributing to bacteremia, septicemia even septic shock. However, the related mechanism remains largely unknown. Preliminary experiment demonstrated that SS2 could largely attach to the surface of neutrophils, implying that this phenomenon maybe contributed to the travel of SS2 in bloodstream and then influenced its pathogenicity. To confirm this hypothesis, using a previously established screening method that combines affinity chromatography (based on liquid chromatography-tandem mass spectrometry) with shotgun proteomics, three candidate proteins (HP0487, HP1765, and HP1111) were identified from SS2 that could interact with neutrophils. Next, by constructing the deletion mutations, we demonstrated that HP0487 of three proteins could significantly influence the adhesion of SS2 to neutrophils. Furthermore, HP0487 was shown to contribute to the anti-phagocytosis of SS2 to neutrophils and RAW264.7 cells. More importantly, the deletion of HP0487 significantly reduced lethality and bacterial loads in vivo of SS2. Thus, our findings demonstrate that HP0487 contributes to SS2 virulence by mediating the adhesion and anti-phagocytosis of SS2 to neutrophils, promoting a better understanding about the pathogenesis of SS2.
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Affiliation(s)
- Xianfeng Hui
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhongmin Xu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lei Cao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Liang Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xian Lin
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yong Yang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiaomei Sun
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qiang Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China; College of Biomedicine and Health, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Meilin Jin
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, China; Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Wuhan, 430070, China.
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Xu B, Zhang P, Zhou H, Sun Y, Tang J, Fan H. Identification of novel genes associated with anti-phagocytic functions in Streptococcus equi subsp. zooepidemicus. Vet Microbiol 2019; 233:28-38. [PMID: 31176409 DOI: 10.1016/j.vetmic.2019.04.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/12/2019] [Accepted: 04/16/2019] [Indexed: 01/13/2023]
Abstract
The anti-phagocytic abilities of bacteria often affect bacterial pathogenicity. Here, random mutant library of Streptococcus equi subsp. zooepidemicus (SEZ) was constructed using transposon mutagenesis. After careful screening, 30 transposon mutants with different transposon insertion sites were identified by conducting quantitative phagocytosis and insertion-site confirmation assays, whose anti-phagocytic abilities were significantly reduced relative to the wild-type strain. Insertion sites of 19 strains were monocistronic, including genes coding membrane proteins, transporters, and enzymes with unknown pathological function, such as sadM, adhP, purD, guaA, alpha-galactosidase coding gene, ABC transporter permease coding gene, metallo-beta-lactamase coding gene, and three secreted enzyme coding genes spuZ, slaB, and endoS, as well as known virulence factor coding genes, such as hasA and szM. The insertion sites of another 11 strains were polycistronic. We focused on four monocistronic-mutant strains: MhtpZ, MspuZ, MslaB, and MendoS. The anti-phagocytic abilities of not only the mutants that were precoincubated with the recombinant proteins, but also the complement strains were significantly more pronounced than those of all four corresponding mutants. The polyclonal antiserum against SlaB or EndoS also significantly decreased the anti-phagocytic capacity of wild-type SEZ. All four mutants exhibited significantly decreased viability in whole blood and reduced lethality in mice relative to the wild-type strain. Thus, we identified a variety of new anti-phagocytic factors, particularly multiple SEZ secreted enzymes. These factors are instrumental in the phagocytic resistance of SEZ in the absence of opsonin. Our results provide a framework for further studies of SEZ pathogenesis and relevant vaccine development for novel potential targets.
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Affiliation(s)
- Bin Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China; National Research Center of Veterinary Biologicals engineering and Technology, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Ping Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China; Poultry Institute, Chinese Academy of Agricultural Sciences, Yangzhou, China
| | - Hong Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yu Sun
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jinsheng Tang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.
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Roy S, Zhu Y, Ma J, Roy AC, Zhang Y, Zhong X, Pan Z, Yao H. Role of ClpX and ClpP in Streptococcus suis serotype 2 stress tolerance and virulence. Microbiol Res 2019; 223-225:99-109. [PMID: 31178057 DOI: 10.1016/j.micres.2019.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 03/19/2019] [Accepted: 04/11/2019] [Indexed: 10/27/2022]
Abstract
Streptococcus suis has received increasing attention for its involvement in severe infections in pigs and humans; however, their pathogenesis remains unclear. ClpX and ClpP, two subunits of the ATP-dependent caseinolytic protease Clp, play key roles in bacterial adaptation to various environmental stresses. In this study, a virulent S. suis serotype 2 strain, ZY05719, was employed to construct clpX and clpP deletion mutants (ΔclpX and ΔclpP, respectively) and their complementation strains. Both ΔclpX and ΔclpP displayed significantly reduced adaptability compared with the wild-type strain, evident through several altered phenotypes: formation of long cell chains, tendency to aggregate in culture, and reduced growth under acidic pH and H2O2-induced oxidative stress. ClpP and ClpX were required for the optimal growth during heat and cold stress, respectively. An in vitro experiment on RAW264.7 macrophage cells showed significantly increased sensitivity of ΔclpX and ΔclpP to phagocytosis compared with the wild-type strain. Mouse infection assays verified the deletion of clpX and clpP led to not only fewer clinical symptoms and lower mortality but also to a marked attenuation in bacterial colonization. These virulence-related phenotypes were restored by genetic complementation. Furthermore, the deletion of clpX or clpP caused a significant decrease in the expression of sodA, tpx, and apuA compared with the wild-type strain, suggesting that these genes may be regulated by ClpX and ClpP as downstream response factors to facilitate the bacterial tolerance against various environmental stresses. Taken together, these results suggest that ClpX and ClpP play important roles in stress tolerance for achieving the full virulence of S. suis serotype 2 during infection.
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Affiliation(s)
- Shipra Roy
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Yinchu Zhu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Jiale Ma
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Animesh Chandra Roy
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Yue Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Xiaojun Zhong
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Zihao Pan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China
| | - Huochun Yao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing 210095, China; OIE Reference Lab for Swine Streptococcosis, Nanjing 210095, China.
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