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Bryant KN, Frick-Cheng AE, Solecki LE, Kroh HK, McDonald WH, Lacy DB, McClain MS, Ohi MD, Cover TL. Species-specific components of the Helicobacter pylori Cag type IV secretion system. Infect Immun 2025; 93:e0049324. [PMID: 40208031 PMCID: PMC12070742 DOI: 10.1128/iai.00493-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2024] [Accepted: 03/08/2025] [Indexed: 04/11/2025] Open
Abstract
Helicobacter pylori strains containing the cag pathogenicity island (PAI) deliver an effector protein (CagA) and non-protein substrates into gastric cells through a process that requires the Cag type IV secretion system (T4SS). The Cag T4SS outer membrane core complex (OMCC) contains multiple copies of five proteins, two of which are species-specific proteins. By using modifications of a previously described OMCC immunopurification method and optimized mass spectrometric methods, we have now isolated additional cag PAI-encoded proteins that are present in lower relative abundance. Four of these proteins (CagW, CagL, CagI, and CagH) do not exhibit sequence relatedness to T4SS components in other bacterial species. Size exclusion chromatography analysis of immunopurified samples revealed that CagW, CagL, CagI, and CagH co-elute with OMCC components. These four Cag proteins are copurified with the OMCC in immunopurifications from a Δcag3 mutant strain (lacking peripheral OMCC components), but not from a ΔcagX mutant strain (defective in OMCC assembly). Negative stain electron microscopy analysis indicated that OMCC preparations isolated from ΔcagW, cagL::kan, ΔcagI, and ΔcagH mutant strains are indistinguishable from wild-type OMCCs. In summary, by using several complementary methods, we have identified multiple species-specific Cag proteins that are associated with the Cag T4SS OMCC and are required for T4SS activity.
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Affiliation(s)
- Kaeli N. Bryant
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | - Lauren E. Solecki
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Heather K. Kroh
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - W. Hayes McDonald
- Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA
| | - D. Borden Lacy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mark S. McClain
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Melanie D. Ohi
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Timothy L. Cover
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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Elbehiry A, Marzouk E, Abalkhail A, Sindi W, Alzahrani Y, Alhifani S, Alshehri T, Anajirih NA, ALMutairi T, Alsaedi A, Alzaben F, Alqrni A, Draz A, Almuzaini AM, Aljarallah SN, Almujaidel A, Abu-Okail A. Pivotal role of Helicobacter pylori virulence genes in pathogenicity and vaccine development. Front Med (Lausanne) 2025; 11:1523991. [PMID: 39850097 PMCID: PMC11756510 DOI: 10.3389/fmed.2024.1523991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2024] [Accepted: 12/13/2024] [Indexed: 01/25/2025] Open
Abstract
One of the most prevalent human infections is Helicobacter pylori (H. pylori), which affects more than half of the global population. Although H. pylori infections are widespread, only a minority of individuals develop severe gastroduodenal disorders. The global resistance of H. pylori to antibiotics has reached concerning levels, significantly impacting the effectiveness of treatment. Consequently, the development of vaccines targeting virulence factors may present a viable alternative for the treatment and prevention of H. pylori infections. This review aims to provide a comprehensive overview of the current understanding of H. pylori infection, with a particular focus on its virulence factors, pathophysiology, and vaccination strategies. This review discusses various virulence factors associated with H. pylori, such as cytotoxin-associated gene A (cagA), vacuolating cytotoxin gene (vacA), outer membrane proteins (OMPs), neutrophil-activated protein (NAP), urease (ure), and catalase. The development of vaccines based on these virulence characteristics is essential for controlling infection and ensuring long-lasting protection. Various vaccination strategies and formulations have been tested in animal models; however, their effectiveness and reproducibility in humans remain uncertain. Different types of vaccines, including vector-based vaccines, inactivated whole cells, genetically modified protein-based subunits, and multiepitope nucleic acid (DNA) vaccines, have been explored. While some vaccines have demonstrated promising results in murine models, only a limited number have been successfully tested in humans. This article provides a thorough evaluation of recent research on H. pylori virulence genes and vaccination methods, offering valuable insights for future strategies to address this global health challenge.
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Affiliation(s)
- Ayman Elbehiry
- Department of Public Health, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Eman Marzouk
- Department of Public Health, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Adil Abalkhail
- Department of Public Health, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Wael Sindi
- Department of Population, Public and Environmental Health, General Administration of Health Services, Ministry of Defense, Riyadh, Saudi Arabia
| | - Yasir Alzahrani
- Department of Psychiatry, King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia
| | - Salem Alhifani
- Department of Psychiatry, King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia
| | - Turki Alshehri
- Department of Dental, Alhada Armed Forces Hospital, Taif, Saudi Arabia
| | - Nuha Abdulaziz Anajirih
- Department of Medical Emergency Services, Faculty of Health Sciences, Umm Al-Qura University, Al-Qunfudah, Saudi Arabia
| | - Turki ALMutairi
- Department of Education and Training, Prince Sultan Military College of Health Sciences, Dammam, Saudi Arabia
| | - Ahmad Alsaedi
- Department of Education and Training, Prince Sultan Military College of Health Sciences, Dammam, Saudi Arabia
| | - Feras Alzaben
- Department of Food Service, King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia
| | - Abdullah Alqrni
- Department of Preventive Medicine, King Fahad Armed Hospital, Jeddah, Saudi Arabia
| | - Abdelmaged Draz
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, Qassim University, Buraydah, Saudi Arabia
| | - Abdulaziz M. Almuzaini
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, Qassim University, Buraydah, Saudi Arabia
| | - Sahar N. Aljarallah
- Department of Pharmacy Sciences, College of Pharmacy, AlMaarefa University, Riyadh, Saudi Arabia
| | - Abdulrahman Almujaidel
- Department of Public Health, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Akram Abu-Okail
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, Qassim University, Buraydah, Saudi Arabia
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Gou L, Yang X, Yun J, Ma Z, Zheng X, Du H, Zhang D. Roles of the components of the cag-pathogenicity island encoded type IV secretion system in Helicobacter pylori. Future Microbiol 2024; 19:1253-1267. [PMID: 39171625 PMCID: PMC11633423 DOI: 10.1080/17460913.2024.2383514] [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: 04/01/2024] [Accepted: 07/19/2024] [Indexed: 08/23/2024] Open
Abstract
The Helicobacter pylori (H. pylori) cytotoxin-associated gene pathogenicity island (cagPAI) encodes 31 genes that assemble the cag type IV secretion system (T4SS) apparatus, which includes structures such as the outer membrane core complex, periplasmic ring, inner membrane complex and bacterial hairs. These proteins interact with each other to inject CagA into the host gastric epithelium. There are also individual unique functions that help H. pylori interfere with host cellular pathways, modulate the immune response and colonize the host for a long time. However, the functions of some of the proteins remain unclear. This review summarizes what is known about the structure and function of these auxiliary components and discusses their role in H. pylori pathogenesis.
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Affiliation(s)
- Lingzhu Gou
- Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
- Department of Gastroenterology, Key Laboratory of Digestive Diseases of Lanzhou University Second Hospital, Lanzhou, People's Republic of China
| | - Xiaoping Yang
- Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
- Department of Gastroenterology, Key Laboratory of Digestive Diseases of Lanzhou University Second Hospital, Lanzhou, People's Republic of China
| | - Jianwei Yun
- Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
| | - Zenghui Ma
- Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
- Department of Gastroenterology, Key Laboratory of Digestive Diseases of Lanzhou University Second Hospital, Lanzhou, People's Republic of China
| | - Xiaofeng Zheng
- Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
| | - Hongwei Du
- Department of Gastroenterology, The Second People's Hospital of Lanzhou City, Lanzhou, People's Republic of China
| | - Dekui Zhang
- Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, People's Republic of China
- Department of Gastroenterology, Key Laboratory of Digestive Diseases of Lanzhou University Second Hospital, Lanzhou, People's Republic of China
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Qin C, Huang GR, Guan AX, Zhou WT, Chen H, Luo PP, Luo XK, Huang YQ, Huang ZS. Mechanistic research: Selenium regulates virulence factors, reducing adhesion ability and inflammatory damage of Helicobacter pylori. World J Gastroenterol 2024; 30:91-107. [PMID: 38293320 PMCID: PMC10823904 DOI: 10.3748/wjg.v30.i1.91] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/22/2023] [Accepted: 12/13/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND The pathogenicity of Helicobacter pylori is dependent on factors including the environment and the host. Although selenium is closely related to pathogenicity as an environmental factor, the specific correlation between them remains unclear. AIM To investigate how selenium acts on virulence factors and reduces their toxicity. METHODS H. pylori strains were induced by sodium selenite. The expression of cytotoxin-associated protein A (CagA) and vacuolating cytotoxin gene A (VacA) was determined by quantitative PCR and Western blotting. Transcriptomics was used to analyze CagA, CagM, CagE, Cag1, Cag3, and CagT. C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction, and H. pylori colonization, inflammatory reactions, and the cell adhesion ability of H. pylori were assessed. RESULTS CagA and VacA expression was upregulated at first and then downregulated in the H. pylori strains after sodium selenite treatment. Their expression was significantly and steadily downregulated after the 5th cycle (10 d). Transcriptome analysis revealed that sodium selenite altered the levels affect H. pylori virulence factors such as CagA, CagM, CagE, Cag1, Cag3, and CagT. Of these factors, CagM and CagE expression was continuously downregulated and further downregulated after 2 h of induction with sodium selenite. Moreover, CagT expression was upregulated before the 3rd cycle (6 d) and significantly downregulated after the 5th cycle. Cag1 and Cag3 expression was upregulated and downregulated, respectively, but no significant change was observed by the 5th cycle. C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction. The extent of H. pylori colonization in the stomach increased; however, sodium selenite also induced a mild inflammatory reaction in the gastric mucosa of H. pylori-infected mice, and the cell adhesion ability of H. pylori was significantly weakened. CONCLUSION These results demonstrate that H. pylori displayed virulence attenuation after the 10th d of sodium selenite treatment. Sodium selenite is a low toxicity compound with strong stability that can reduce the cell adhesion ability of H. pylori, thus mitigating the inflammatory damage to the gastric mucosa.
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Affiliation(s)
- Chun Qin
- Guangxi Technology Innovation Cooperation Base of Prevention and Control Pathogenic Microbes with Drug Resistance, Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
- Department of Digestive Diseases, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
| | - Gan-Rong Huang
- Guangxi Technology Innovation Cooperation Base of Prevention and Control Pathogenic Microbes with Drug Resistance, Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
- Key Laboratory of the Prevention and Treatment of Drug Resistant Microbial Infecting, Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
| | - Ai-Xing Guan
- Guangxi Technology Innovation Cooperation Base of Prevention and Control Pathogenic Microbes with Drug Resistance, Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
- Department of Digestive Diseases, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
| | - Wen-Ting Zhou
- Guangxi Technology Innovation Cooperation Base of Prevention and Control Pathogenic Microbes with Drug Resistance, Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
- Key Laboratory of the Prevention and Treatment of Drug Resistant Microbial Infecting, Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
| | - Hao Chen
- Department of Pathology, Wannan Medical College, Wuhu 241002, Anhui Province, China
| | - Pei-Pei Luo
- Department of Gastroenterology, Wujin People’s Hospital affiliated to Jiangsu University, Changzhou 213004, Jiangsu Province, China
| | - Xian-Ke Luo
- Department of Gastroenterology, Guangzhou Liwan District People's Hospital, Guangzhou 510370, Guangdong Province, China
| | - Yan-Qiang Huang
- Guangxi Technology Innovation Cooperation Base of Prevention and Control Pathogenic Microbes with Drug Resistance, Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
- Key Laboratory of the Prevention and Treatment of Drug Resistant Microbial Infecting, Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
| | - Zan-Song Huang
- Guangxi Technology Innovation Cooperation Base of Prevention and Control Pathogenic Microbes with Drug Resistance, Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
- Department of Digestive Diseases, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise 533000, Guangxi Zhuang Autonomous Region, China
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Saberi S, Shans N, Ghaffari S, Esmaeili M, Mohammadi M. The role of CEACAMs versus integrins in Helicobacter pylori CagA translocation: a systematic review. Microbes Infect 2024; 26:105246. [PMID: 37926369 DOI: 10.1016/j.micinf.2023.105246] [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: 03/04/2023] [Revised: 10/24/2023] [Accepted: 10/30/2023] [Indexed: 11/07/2023]
Abstract
The delivery of Helicobacter pylori CagA into host cells was long believed to occur through the integrin cell surface receptors. However, the role of CEACAM receptors has recently been highlighted, instead. Here, we have categorized the existing experimental evidence according to whether deletion, upregulation, downregulation, or inhibition of the target ligands (T4SS or HopQ) or receptors (integrins or CEACAMs), result in alterations in CagA phosphorylation, cell elongation, or IL-8 production. According to our analysis, the statistics favor the essence of most of the T4SS constituents and the involvement of HopQ adhesin in all three functions. Concerning the integrin family, the collected data is controversial, but yielding towards it being dispensable or involved in CagA translocation. Yet, regarding cell elongation, more events are showing β1 integrin being involved, than αvβ4 being inhibitory. Concerning IL-8 secretion, again there are more events showing α5, β1 and β6 integrins to be involved, than those showing inhibitory roles for β1, β4 and β6 integrins. Finally, CEACAM 1, 3, and 5 are identified as mostly essential or involved in CagA phosphorylation, whereasCEACAM 4, 7, and 8 are found dispensable and CEACAM6 is under debate. Conversely, CEACAM1, 5 and 6 appear mostly dispensable for cell elongation. Noteworthy is the choice of cell type, bacterial strain, multiplicity and duration of infection, as well as the sensitivity of the detection methods, all of which can affect the variably obtained results.
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Affiliation(s)
- Samaneh Saberi
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Nazanin Shans
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Saba Ghaffari
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Maryam Esmaeili
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Marjan Mohammadi
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
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Li S, Zhao W, Xia L, Kong L, Yang L. How Long Will It Take to Launch an Effective Helicobacter pylori Vaccine for Humans? Infect Drug Resist 2023; 16:3787-3805. [PMID: 37342435 PMCID: PMC10278649 DOI: 10.2147/idr.s412361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/02/2023] [Indexed: 06/22/2023] Open
Abstract
Helicobacter pylori infection often occurs in early childhood, and can last a lifetime if not treated with medication. H. pylori infection can also cause a variety of stomach diseases, which can only be treated with a combination of antibiotics. Combinations of antibiotics can cure H. pylori infection, but it is easy to relapse and develop drug resistance. Therefore, a vaccine is a promising strategy for prevention and therapy for the infection of H. pylori. After decades of research and development, there has been no appearance of any H. pylori vaccine reaching the market, unfortunately. This review summarizes the aspects of candidate antigens, immunoadjuvants, and delivery systems in the long journey of H. pylori vaccine research, and also introduces some clinical trials that have displayed encouraging or depressing results. Possible reasons for the inability of an H. pylori vaccine to be available over the counter are cautiously discussed and some propositions for the future of H. pylori vaccines are outlined.
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Affiliation(s)
- Songhui Li
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 210009People’s Republic of China
| | - Wenfeng Zhao
- Department of Biochemistry, School of Life Science and Technology, China Pharmaceutical University, Nanjing, 210009People’s Republic of China
| | - Lei Xia
- Bloomage Biotechnology Corporation Limited, Jinan, People’s Republic of China
| | - Lingyi Kong
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 210009People’s Republic of China
| | - Lei Yang
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, 210009People’s Republic of China
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Zhang Y, Li X, Shan B, Zhang H, Zhao L. Perspectives from recent advances of Helicobacter pylori vaccines research. Helicobacter 2022; 27:e12926. [PMID: 36134470 DOI: 10.1111/hel.12926] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/25/2022] [Accepted: 08/17/2022] [Indexed: 12/09/2022]
Abstract
BACKGROUND Helicobacter pylori (H. pylori) infection is the main factor leading to some gastric diseases. Currently, H. pylori infection is primarily treated with antibiotics. However, with the widespread application of antibiotics, H. pylori resistance to antibiotics has also gradually increased year by year. Vaccines may be an alternative solution to clear H. pylori. AIMS By reviewing the recent progress on H. pylori vaccines, we expected it to lead to more research efforts to accelerate breakthroughs in this field. MATERIALS & METHODS We searched the research on H. pylori vaccine in recent years through PubMed®, and then classified and summarized these studies. RESULTS The study of the pathogenic mechanism of H. pylori has led to the development of vaccines using some antigens, such as urease, catalase, and heat shock protein (Hsp). Based on these antigens, whole-cell, subunit, nucleic acid, vector, and H. pylori exosome vaccines have been tested. DISCUSSION At present, researchers have developed many types of vaccines, such as whole cell vaccines, subunit vaccines, vector vaccines, etc. However, although some of these vaccines induced protective immunity in mouse models, only a few were able to move into human trials. We propose that mRNA vaccine may play an important role in preventing or treating H. pylori infection. The current study shows that we have developed various types of vaccines based on the virulence factors of H. pylori. However, only a few vaccines have entered human clinical trials. In order to improve the efficacy of vaccines, it is necessary to enhance T-cell immunity. CONCLUSION We should fully understand the pathogenic mechanism of H. pylori and find its core antigen as a vaccine target.
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Affiliation(s)
- Ying Zhang
- Research Center, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xiaoya Li
- Research Center, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Baoen Shan
- Research Center, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Hongtao Zhang
- University of Pennsylvania School of Medicine Philadelphia, Philadelphia, Pennsylvania, USA
| | - Lianmei Zhao
- Research Center, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
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Disruption of VirB6 Paralogs in Anaplasma phagocytophilum Attenuates Its Growth. J Bacteriol 2020; 202:JB.00301-20. [PMID: 32928930 PMCID: PMC7648143 DOI: 10.1128/jb.00301-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/08/2020] [Indexed: 01/25/2023] Open
Abstract
Knowledge of the T4SS is derived from model systems, such as Agrobacterium tumefaciens. The structure of the T4SS in Rickettsiales differs from the classical arrangement. These differences include missing and duplicated components with structural alterations. Particularly, two sequenced virB6-4 genes encode unusual C-terminal structural extensions resulting in proteins of 4,322 (GenBank accession number AGR79286.1) and 9,935 (GenBank accession number ANC34101.1) amino acids. To understand how the T4SS is used in A. phagocytophilum, we describe the expression of the virB6 paralogs and explore their role as the bacteria replicate within its host cell. Conclusions about the importance of these paralogs for colonization of human and tick cells are supported by the deficient phenotype of an A. phagocytophilum mutant isolated from a sequence-defined transposon insertion library. Many pathogenic bacteria translocate virulence factors into their eukaryotic hosts by means of type IV secretion systems (T4SS) spanning the inner and outer membranes. Genes encoding components of these systems have been identified within the order Rickettsiales based upon their sequence similarities to other prototypical systems. Anaplasma phagocytophilum strains are obligate intracellular, tick-borne bacteria that are members of this order. The organization of these components at the genomic level was determined in several Anaplasma phagocytophilum strains, showing overall conservation, with the exceptions of the virB2 and virB6 genes. The virB6 loci are characterized by the presence of four virB6 copies (virB6-1 through virB6-4) arranged in tandem within a gene cluster known as the sodB-virB operon. Interestingly, the virB6-4 gene varies significantly in length among different strains due to extensive tandem repeats at the 3′ end. To gain an understanding of how these enigmatic virB6 genes function in A. phagocytophilum, we investigated their expression in infected human and tick cells. Our results show that these genes are expressed by A. phagocytophilum replicating in both cell types and that VirB6-3 and VirB6-4 proteins are surface exposed. Analysis of an A. phagocytophilum mutant carrying the Himar1 transposon within the virB6-4 gene demonstrated that the insertion not only disrupted its expression but also exerted a polar effect on the sodB-virB operon. Moreover, the altered expression of genes within this operon was associated with the attenuated in vitro growth of A. phagocytophilum in human and tick cells, indicating the importance of these genes in the physiology of this obligate intracellular bacterium in such different environments. IMPORTANCE Knowledge of the T4SS is derived from model systems, such as Agrobacterium tumefaciens. The structure of the T4SS in Rickettsiales differs from the classical arrangement. These differences include missing and duplicated components with structural alterations. Particularly, two sequenced virB6-4 genes encode unusual C-terminal structural extensions resulting in proteins of 4,322 (GenBank accession number AGR79286.1) and 9,935 (GenBank accession number ANC34101.1) amino acids. To understand how the T4SS is used in A. phagocytophilum, we describe the expression of the virB6 paralogs and explore their role as the bacteria replicate within its host cell. Conclusions about the importance of these paralogs for colonization of human and tick cells are supported by the deficient phenotype of an A. phagocytophilum mutant isolated from a sequence-defined transposon insertion library.
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Chehelgerdi M, Doosti A. Effect of the cagW-based gene vaccine on the immunologic properties of BALB/c mouse: an efficient candidate for Helicobacter pylori DNA vaccine. J Nanobiotechnology 2020; 18:63. [PMID: 32316990 PMCID: PMC7175550 DOI: 10.1186/s12951-020-00618-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 04/13/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Helicobacter pylori (H. pylori) infect more than half of the world population, and they cause different serious diseases such as gastric carcinomas. This study aims to design a vaccine on the basis of cagW against H. pylori infection. After pcDNA3.1 (+)-cagW-CS-NPs complex is produced, it will be administered into the muscles of healthy BALB/c mice in order to study the effect of this DNA vaccine on the interleukin status of mice, representing its effect on the immune system. After that, the results will be compared with the control groups comprising the administration of cagW-pCDNA3.1 (+) vaccine, the administration of chitosan and the administration of PBS in the muscles of mice. METHODS The cagW gene of H. pylori was amplified by employing PCR, whose product was then cloned into the pcDNA3.1 (+) vector, and this cloning was confirmed by PCR and BamHI/EcoRV restriction enzyme digestion. CagW gene DNA vaccine was encapsulated in chitosan nanoparticles (pcDNA3.1 (+)-cagW-CS-NPs) using a complex coacervation method. The stability and in vitro expression of chitosan nanoparticles were studied by DNase I digestion and transfection, and the immune responses elicited in specific pathogen-free (SPF) mice by the pcDNA3.1 (+)-cagW-CS-NPs were evaluated. Apart from that, the protective potential pcDNA3.1 (+)-cagW-CS-NPs was evaluated by challenging with H. pylori. RESULTS The pcDNA3.1 (+)-cagW-CS-NPs comprises cagW gene of H. pylori that is encapsulated in chitosan nanoparticles, produced with good morphology, high stability, a mean diameter of 117.7 nm, and a zeta potential of + 5.64 mV. Moreover, it was confirmed that chitosan encapsulation protects the DNA plasmid from DNase I digestion, and the immunofluorescence assay showed that the cagW gene could express in HDF cells and maintain good bioactivity at the same time. In comparison to the mice immunized with the control plasmid, in vivo immunization revealed that mice immunized with pcDNA3.1 (+)-cagW-NPs showed better immune responses and prolonged release of the plasmid DNA. CONCLUSIONS This research proves chitosan-DNA nanoparticles as potent immunization candidates against H. pylori infection and paves the way for further developments in novel vaccines encapsulated in chitosan nanoparticles.
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Affiliation(s)
- Mohammad Chehelgerdi
- Young Researchers and Elite Club, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
| | - Abbas Doosti
- Biotechnology Research Center, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
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