1
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Holland RL, Bosi KD, Seeger AY, Blanke SR. Restoration of mitochondrial structure and function within Helicobacter pylori VacA intoxicated cells. ADVANCES IN MICROBIOLOGY 2023; 13:399-419. [PMID: 37654621 PMCID: PMC10470862 DOI: 10.4236/aim.2023.138026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
The Helicobacter pylori vacuolating cytotoxin (VacA) is an intracellular, mitochondrial-targeting exotoxin that rapidly causes mitochondrial dysfunction and fragmentation. Although VacA targeting of mitochondria has been reported to alter overall cellular metabolism, there is little known about the consequences of extended exposure to the toxin. Here, we describe studies to address this gap in knowledge, which have revealed that mitochondrial dysfunction and fragmentation are followed by a time-dependent recovery of mitochondrial structure, mitochondrial transmembrane potential, and cellular ATP levels. Cells exposed to VacA also initially demonstrated a reduction in oxidative phosphorylation, as well as increase in compensatory aerobic glycolysis. These metabolic alterations were reversed in cells with limited toxin exposure, congruent with the recovery of mitochondrial transmembrane potential and the absence of cytochrome c release from the mitochondria. Taken together, these results are consistent with a model that mitochondrial structure and function are restored in VacA-intoxicated cells.
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Affiliation(s)
- Robin L. Holland
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
| | - Kristopher D. Bosi
- Department of Microbiology, School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
| | - Ami Y. Seeger
- Department of Microbiology, School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
| | - Steven R. Blanke
- Department of Pathobiology, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
- Department of Microbiology, School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, 61801
- Biomedical and Translational Sciences Department, Carle Illinois College of Medicine, University of Illinois, Urbana, Illinois 61801
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2
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Walker E, van Niekerk S, Hanning K, Kelton W, Hicks J. Mechanisms of host manipulation by Neisseria gonorrhoeae. Front Microbiol 2023; 14:1119834. [PMID: 36819065 PMCID: PMC9935845 DOI: 10.3389/fmicb.2023.1119834] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 01/18/2023] [Indexed: 02/05/2023] Open
Abstract
Neisseria gonorrhoeae (also known as gonococcus) has been causing gonorrhoea in humans since ancient Egyptian times. Today, global gonorrhoea infections are rising at an alarming rate, in concert with an increasing number of antimicrobial-resistant strains. The gonococcus has concurrently evolved several intricate mechanisms that promote pathogenesis by evading both host immunity and defeating common therapeutic interventions. Central to these adaptations is the ability of the gonococcus to manipulate various host microenvironments upon infection. For example, the gonococcus can survive within neutrophils through direct regulation of both the oxidative burst response and maturation of the phagosome; a concerning trait given the important role neutrophils have in defending against invading pathogens. Hence, a detailed understanding of how N. gonorrhoeae exploits the human host to establish and maintain infection is crucial for combating this pathogen. This review summarizes the mechanisms behind host manipulation, with a central focus on the exploitation of host epithelial cell signaling to promote colonization and invasion of the epithelial lining, the modulation of the host immune response to evade both innate and adaptive defenses, and the manipulation of host cell death pathways to both assist colonization and combat antimicrobial activities of innate immune cells. Collectively, these pathways act in concert to enable N. gonorrhoeae to colonize and invade a wide array of host tissues, both establishing and disseminating gonococcal infection.
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Affiliation(s)
- Emma Walker
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand
| | - Stacy van Niekerk
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand
| | - Kyrin Hanning
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand
| | - William Kelton
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand,Te Aka Mātuatua School of Science, University of Waikato, Hamilton, New Zealand
| | - Joanna Hicks
- Te Huataki Waiora, School of Health, University of Waikato, Hamilton, New Zealand,*Correspondence: Joanna Hicks,
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3
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Onorini D, Borel N, Schoborg RV, Leonard CA. Neisseria gonorrhoeae Limits Chlamydia trachomatis Inclusion Development and Infectivity in a Novel In Vitro Co-Infection Model. Front Cell Infect Microbiol 2022; 12:911818. [PMID: 35873141 PMCID: PMC9300984 DOI: 10.3389/fcimb.2022.911818] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (Ng) are the most common bacterial sexually transmitted infections (STIs) worldwide. The primary site of infection for both bacteria is the epithelium of the endocervix in women and the urethra in men; both can also infect the rectum, pharynx and conjunctiva. Ct/Ng co-infections are more common than expected by chance, suggesting Ct/Ng interactions increase susceptibility and/or transmissibility. To date, studies have largely focused on each pathogen individually and models exploring co-infection are limited. We aimed to determine if Ng co-infection influences chlamydial infection and development and we hypothesized that Ng-infected cells are more susceptible to chlamydial infection than uninfected cells. To address this hypothesis, we established an in vitro model of Ct/Ng co-infection in cultured human cervical epithelial cells. Our data show that Ng co-infection elicits an anti-chlamydial effect by reducing chlamydial infection, inclusion size, and subsequent infectivity. Notably, the anti-chlamydial effect is dependent on Ng viability but not extracellular nutrient depletion or pH modulation. Though this finding is not consistent with our hypothesis, it provides evidence that interaction of these bacteria in vitro influences chlamydial infection and development. This Ct/Ng co-infection model, established in an epithelial cell line, will facilitate further exploration into the pathogenic interplay between Ct and Ng.
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Affiliation(s)
- Delia Onorini
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Nicole Borel
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Robert V. Schoborg
- Department of Medical Education, Center for Infectious Disease, Inflammation and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Cory Ann Leonard
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
- *Correspondence: Cory Ann Leonard,
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4
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Zhang S, Zhang Y, Gan L, Wei F, Chai B, A Aljaafreh AAH, Liu X, Duan X, Jiang J, Wang X, He M, Huang X, Cai H, Chen T, Chen H. Progesterone Suppresses Neisseria gonorrhoeae-Induced Inflammation Through Inhibition of NLRP3 Inflammasome Pathway in THP-1 Cells and Murine Models. Front Microbiol 2021; 12:570093. [PMID: 33633700 PMCID: PMC7900005 DOI: 10.3389/fmicb.2021.570093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 01/15/2021] [Indexed: 01/01/2023] Open
Abstract
Asymptomatic/subclinical gonococcal infections in females continue to be prevalent within the general population, thus emerging as a global health problem. However, the reasons for these clinical manifestations are unknown. Our group had previously found out that in females, asymptomatic gonococcal infections correlate with higher serum progesterone (P4) levels and lower IL-1β levels in cervical secretions. We used murine infection model and THP-1 cells to determine whether P4 exerts anti-inflammatory effects on gonococcal infections. In the murine infection model, P4 (1 mg/day) inhibited the inflammatory effects induced by gonococcal infections which led to decreased neutrophil infiltration, reduced polymorphonuclear neutrophils (PMNs) numbers, IL-1β, TNF-α, and IL-6 levels in vaginal secretions. In addition, P4 down-regulated the mRNA and protein levels of NLRP3, associated with lower mRNA levels of pro-IL-1β, repressed caspase-1 activity in genital tissues and THP-1 cells. Moreover, P4 suppressed the phosphorylation levels of NF-κB and attenuated Neisseria gonorrhoeae (N. gonorrhoeae, gonococci or GC)-induced ROS generation. This is consistent with the two signals required for activation of the NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome. In conclusion, our result shows that P4 suppresses the gonococci induced-inflammation, especially through the NLRP3 inflammasome pathway, and partially explains the pathogenesis of asymptomatic GC infection in women.
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Affiliation(s)
- Song Zhang
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yingmiao Zhang
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan, China.,Department of Clinical Laboratory, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Tchnology, Wuhan, China
| | - Lu Gan
- Department of Dermatology, Zhongnan Hospital, Wuhan University, Wuhan, China
| | - Fen Wei
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bao Chai
- Department of Dermatology, The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Department of Dermatology, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
| | - Amaneh Abdel Hafez A Aljaafreh
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinxin Liu
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoru Duan
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian Jiang
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin Wang
- Department of Dermatology, Affiliated Hospital of Nantong University, Nantong, China
| | - Mengwen He
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xian Huang
- Department of Dermatology, The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
| | - Huahua Cai
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan, China
| | - Tie Chen
- Department of Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan, China
| | - Hongxiang Chen
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Dermatology, The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China.,Department of Dermatology, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
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5
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Luo F, Shu M, Gong S, Wen Y, He B, Su S, Li Z. Antiapoptotic activity of Chlamydia trachomatis Pgp3 protein involves activation of the ERK1/2 pathway mediated by upregulation of DJ-1 protein. Pathog Dis 2020; 77:5714752. [PMID: 31971555 DOI: 10.1093/femspd/ftaa003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/22/2020] [Indexed: 02/07/2023] Open
Abstract
Chlamydia trachomatis has evolved strategies to prevent host cell apoptosis to evade the host immune defense. However, the precise mechanisms of antiapoptotic activity of C. trachomatis still need to be clarified. Pgp3, one of eight plasmid proteins of C. trachomatis, has been identified to be closely associated with chlamydial virulence. In this study, we attempted to explore the effects and the mechanisms of Pgp3 protein on apoptosis in HeLa cells; the results showed that Pgp3 increased Bcl-2/Bax ratio and prevented caspase-3 activation to suppress apoptosis induced by TNF-α and cycloheximide (CHX) through ERK1/2 pathway activation. Downregulation of DJ-1 with siRNA-DJ-1(si-DJ-1) reduced ERK1/2 phosphorylation and elevated apoptotic rate significantly in Pgp3-HeLa cells. However, inhibition of ERK1/2 signal pathway with ERK inhibitor PD98059 had little effect on DJ-1 expression. These findings confirm that plasmid protein Pgp3 contributes to apoptosis resistance through ERK1/2 signal pathway mediated by upregulation of DJ-1 expression. Therefore, the present study provided novel insights into the role of Pgp3 in apoptosis and suggested that manipulation of the host apoptosis response could be a new approach for the prevention and treatment of C. trachomatis infection.
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Affiliation(s)
- Fangzhen Luo
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, P. R. China
| | - Mingyi Shu
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, P. R. China
| | - Silu Gong
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, P. R. China
| | - Yating Wen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, P. R. China
| | - Bei He
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, P. R. China
| | - Shengmei Su
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, P. R. China
| | - Zhongyu Li
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, Hunan 421001, P. R. China
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6
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Li LH, Lin JS, Chiu HW, Lin WY, Ju TC, Chen FH, Chernikov OV, Liu ML, Chang JC, Hsu CH, Chen A, Ka SM, Gao HW, Hua KF. Mechanistic Insight Into the Activation of the NLRP3 Inflammasome by Neisseria gonorrhoeae in Macrophages. Front Immunol 2019; 10:1815. [PMID: 31417575 PMCID: PMC6685137 DOI: 10.3389/fimmu.2019.01815] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 07/18/2019] [Indexed: 12/15/2022] Open
Abstract
Gonorrhea is a type III legal communicable disease caused by Neisseria gonorrhoeae (NG), one of the most common sexually transmitted bacteria worldwide. NG infection can cause urethritis or systemic inflammation and may lead to infertility or other complications. The NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome is a protein complex composed of NLRP3, apoptosis-associated speck-like protein and caspase-1 and is an important part of the cellular machinery controlling the release of interleukin (IL)-1β and IL-18 and the pathogenesis of numerous infectious diseases. It has been reported that NG infection activates the NLRP3 inflammasome; however, the underlying mechanism remain unclear. In this report, the signaling pathways involved in the regulation of NG-mediated NLRP3 inflammasome activation in macrophages were studied. The results indicated that viable NG, but not heat-killed or freeze/thaw-killed NG, activated the NLRP3 inflammasome in macrophages through toll-like receptor 2, but not toll-like receptor 4. NG infection provided the priming signal to the NLRP3 inflammasome that induced the expression of NLRP3 and IL-1β precursor through the nuclear factor kappa B and mitogen-activated protein kinase pathways. In addition, NG infection provided the activation signal to the NLRP3 inflammasome that activated caspase-1 through P2X7 receptor-dependent potassium efflux, lysosomal acidification, mitochondrial dysfunction, and reactive oxygen species production pathways. Furthermore, we demonstrated that NLRP3 knockout increased phagocytosis of bacteria by macrophages and increases the bactericidal activity of macrophages against NG. These findings provide potential molecular targets for the development of anti-inflammatory drugs that could ameliorate NG-mediated inflammation.
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Affiliation(s)
- Lan-Hui Li
- Department of Laboratory Medicine, Linsen Chinese Medicine and Kunming Branch, Taipei City Hospital, Taipei, Taiwan.,Department of Pathology, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
| | - Jia-Sing Lin
- Department of Laboratory Medicine, Linsen Chinese Medicine and Kunming Branch, Taipei City Hospital, Taipei, Taiwan.,Department of Pathology, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
| | - Hsiao-Wen Chiu
- National Defense Medical Center, Graduate Institute of Life Sciences, Taipei, Taiwan
| | - Wen-Yu Lin
- Division of Cardiology, Department of Internal Medicine, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
| | - Tz-Chuen Ju
- Department of Animal Science and Biotechnology, Tunghai University, Taichung City, Taiwan
| | - Fang-Hsin Chen
- Department of Medical Imaging and Radiological Sciences, Chang Gung University, Taoyuan City, Taiwan
| | - Oleg V Chernikov
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry (PIBOC), Far Eastern Branch of the Russian Academy of Sciences (FEB RAS), Vladivostok, Russia
| | - May-Lan Liu
- Department of Nutritional Science, Toko University, Chiayi City, Taiwan
| | - Jen-Che Chang
- Department of Pathology, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
| | - Chung-Hua Hsu
- Department of Laboratory Medicine, Linsen Chinese Medicine and Kunming Branch, Taipei City Hospital, Taipei, Taiwan.,School of Medicine, Institute of Traditional Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ann Chen
- Department of Pathology, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
| | - Shuk-Man Ka
- National Defense Medical Center, Graduate Institute of Life Sciences, Taipei, Taiwan.,Department of Medicine, National Defense Medical Center, Graduate Institute of Aerospace and Undersea Medicine, Taipei, Taiwan
| | - Hong-Wei Gao
- Department of Pathology, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
| | - Kuo-Feng Hua
- Department of Pathology, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan.,Department of Biotechnology and Animal Science, National Ilan University, Yilan City, Taiwan.,Department of Medical Research, China Medical University Hospital, China Medical University, Taichung City, Taiwan
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7
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Kim WJ, Mai A, Weyand NJ, Rendón MA, Van Doorslaer K, So M. Neisseria gonorrhoeae evades autophagic killing by downregulating CD46-cyt1 and remodeling lysosomes. PLoS Pathog 2019; 15:e1007495. [PMID: 30753248 PMCID: PMC6388937 DOI: 10.1371/journal.ppat.1007495] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 02/25/2019] [Accepted: 12/01/2018] [Indexed: 12/20/2022] Open
Abstract
The Gram-negative human pathogen N. gonorrhoeae (Ngo) quickly attaches to epithelial cells, and large numbers of the bacteria remain on the cell surface for prolonged periods. Ngo invades cells but few viable intracellular bacteria are recovered until later stages of infection, leading to the assumption that Ngo is a weak invader. On the cell surface, Ngo quickly recruits CD46-cyt1 to the epithelial cell cortex directly beneath the bacteria and causes its cleavage by metalloproteinases and Presenilin/γSecretease; how these interactions affect the Ngo lifecycle is unknown. Here, we show Ngo induces an autophagic response in the epithelial cell through CD46-cyt1/GOPC, and this response kills early invaders. Throughout infection, the pathogen slowly downregulates CD46-cyt1 and remodeling of lysosomes, another key autophagy component, and these activities ultimately promote intracellular survival. We present a model on the dynamics of Ngo infection and describe how this dual interference with the autophagic pathway allows late invaders to survive within the cell.
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Affiliation(s)
- Won J. Kim
- BIO5 Institute, University of Arizona, Tucson, AZ, United States of America
- Department of Immunobiology, University of Arizona, Tucson, AZ, United States of America
- * E-mail:
| | - Annette Mai
- BIO5 Institute, University of Arizona, Tucson, AZ, United States of America
| | - Nathan J. Weyand
- Department of Biological Sciences, Ohio University, Athens, OH, United States of America
| | - Maria A. Rendón
- BIO5 Institute, University of Arizona, Tucson, AZ, United States of America
- Department of Immunobiology, University of Arizona, Tucson, AZ, United States of America
| | - Koenraad Van Doorslaer
- BIO5 Institute, University of Arizona, Tucson, AZ, United States of America
- Department of Immunobiology, University of Arizona, Tucson, AZ, United States of America
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ, United States of America
| | - Magdalene So
- BIO5 Institute, University of Arizona, Tucson, AZ, United States of America
- Department of Immunobiology, University of Arizona, Tucson, AZ, United States of America
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8
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Escobar A, Rodas PI, Acuña-Castillo C. Macrophage- Neisseria gonorrhoeae Interactions: A Better Understanding of Pathogen Mechanisms of Immunomodulation. Front Immunol 2018; 9:3044. [PMID: 30627130 PMCID: PMC6309159 DOI: 10.3389/fimmu.2018.03044] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 12/10/2018] [Indexed: 12/19/2022] Open
Abstract
Neisseria gonorrhoeae is a significant health problem worldwide due to multi-drug resistance issues and absence of an effective vaccine. Patients infected with N. gonorrhoeae have not shown a better immune response in successive infections. This might be explained by the fact that N. gonorrhoeae possesses several mechanisms to evade the innate and adaptative immune responses at different levels. Macrophages are a key cellular component in the innate immune response against microorganisms. The current information suggests that gonococcus can hijack the host response by mechanisms that involve the control of macrophages activity. In this mini review, we intend to condense the recent knowledge on the macrophage–N. gonorrhoeae interactions with a focus on strategies developed by gonococcus to evade or to exploit immune response to establish a successful infection. Finally, we discuss the opportunities and challenges of therapeutics for controlling immune manipulation by N. gonorrhoeae.
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Affiliation(s)
- Alejandro Escobar
- Laboratorio Biología Celular y Molecular, Instituto de Investigación en Ciencias Odontológicas, Facultad de Odontología, Universidad de Chile, Santiago, Chile
| | - Paula I Rodas
- Laboratorio de Microbiología Médica y Patogénesis, Facultad de Medicina, Universidad Andrés Bello, Concepción, Chile
| | - Claudio Acuña-Castillo
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
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9
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Lv C, Wang H, Tong Y, Yin H, Wang D, Yan Z, Liang Y, Wu D, Su Q. The function of BTG3 in colorectal cancer cells and its possible signaling pathway. J Cancer Res Clin Oncol 2018; 144:295-308. [PMID: 29270670 PMCID: PMC5794823 DOI: 10.1007/s00432-017-2561-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 12/16/2017] [Indexed: 01/02/2023]
Abstract
PURPOSE B-cell translocation gene 3 (BTG3) has been identified as a candidate driver gene for various cancers, but its specific role in colorectal cancer (CRC) is poorly understood. We aimed to investigate the relationship between expression of BTG3 and clinicopathological features and prognosis, as well as to explore the effects and the role of a possible BTG3 molecular mechanism on aggressive colorectal cancer behavior. METHODS BTG3 expression was assessed by immunohistochemistry (IHC) on specimens from 140 patients with CRC. The association of BTG3 expression with clinicopathological features was examined. To confirm the biological role of BTG3 in CRC, two CRC cell lines expressing BTG3 were used and BTG3 expression was knocked down by shRNA. CCK-8, cell cycle, apoptosis, migration, and invasion assays were performed. The influence of BTG3 knockdown was further investigated by genomic microarray to uncover the potential molecular mechanisms underlying BTG3-mediated CRC development and progression. RESULTS BTG3 was downregulated in colorectal cancer tissues and positively correlated with pathological classification (p = 0.037), depth of invasion (p = 0.016), distant metastasis (p = 0.024), TNM stage (p = 0.007), and overall survival (OS) and disease-free survival (DFS). BTG3 knockdown promoted cell proliferation, migration, invasion, relieved G2 arrest, and inhibited apoptosis in HCT116 and LoVo cells. A genomic microarray analysis showed that numerous tumor-associated signaling pathways and oncogenes were altered by BTG3 knockdown. At the mRNA level, nine genes referred to the extracellular-regulated kinase/mitogen-activated protein kinase pathway were differentially expressed. Western blotting revealed that BTG3 knockdown upregulated PAK2, RPS6KA5, YWHAB, and signal transducer and activator of transcription (STAT)3 protein levels, but downregulated RAP1A, DUSP6, and STAT1 protein expression, which was consistent with the genomic microarray data. CONCLUSIONS BTG3 expression might contribute to CRC carcinogenesis. BTG3 knockdown might strengthen the aggressive colorectal cancer behavior.
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Affiliation(s)
- Chi Lv
- Department of General Surgery, Shengjing Hospital Affiliated to China Medical University, Shenyang City, Liaoning Province, 110004, People's Republic of China
- Department of General Surgery, General Hospital of Shenyang Military Region, Shenyang, People's Republic of China
| | - Heling Wang
- Department of General Surgery, Shengjing Hospital Affiliated to China Medical University, Shenyang City, Liaoning Province, 110004, People's Republic of China
| | - Yuxin Tong
- Medical Research Center, Shengjing Hospital of China Medical University, Shenyang, People's Republic of China
| | - Hongzhuan Yin
- Department of General Surgery, Shengjing Hospital Affiliated to China Medical University, Shenyang City, Liaoning Province, 110004, People's Republic of China
| | - Dalu Wang
- Department of General Surgery, Shengjing Hospital Affiliated to China Medical University, Shenyang City, Liaoning Province, 110004, People's Republic of China
| | - Zhaopeng Yan
- Department of General Surgery, Shengjing Hospital Affiliated to China Medical University, Shenyang City, Liaoning Province, 110004, People's Republic of China
| | - Yichao Liang
- Department of General Surgery, Shengjing Hospital Affiliated to China Medical University, Shenyang City, Liaoning Province, 110004, People's Republic of China
| | - Di Wu
- Department of General Surgery, Shengjing Hospital Affiliated to China Medical University, Shenyang City, Liaoning Province, 110004, People's Republic of China
| | - Qi Su
- Department of General Surgery, Shengjing Hospital Affiliated to China Medical University, Shenyang City, Liaoning Province, 110004, People's Republic of China.
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10
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Cook SJ, Stuart K, Gilley R, Sale MJ. Control of cell death and mitochondrial fission by ERK1/2 MAP kinase signalling. FEBS J 2017; 284:4177-4195. [PMID: 28548464 PMCID: PMC6193418 DOI: 10.1111/febs.14122] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/08/2017] [Accepted: 05/24/2017] [Indexed: 12/14/2022]
Abstract
The ERK1/2 signalling pathway is best known for its role in connecting activated growth factor receptors to changes in gene expression due to activated ERK1/2 entering the nucleus and phosphorylating transcription factors. However, active ERK1/2 also translocate to a variety of other organelles including the endoplasmic reticulum, endosomes, golgi and mitochondria to access specific substrates and influence cell physiology. In this article, we review two aspects of ERK1/2 signalling at the mitochondria that are involved in regulating cell fate decisions. First, we describe the prominent role of ERK1/2 in controlling the BCL2-regulated, cell-intrinsic apoptotic pathway. In most cases ERK1/2 signalling promotes cell survival by activating prosurvival BCL2 proteins (BCL2, BCL-xL and MCL1) and repressing prodeath proteins (BAD, BIM, BMF and PUMA). This prosurvival signalling is co-opted by oncogenes to confer cancer cell-specific survival advantages and we describe how this information has been used to develop new drug combinations. However, ERK1/2 can also drive the expression of the prodeath protein NOXA to control 'autophagy or apoptosis' decisions during nutrient starvation. We also describe recent studies demonstrating a link between ERK1/2 signalling, DRP1 and the mitochondrial fission machinery and how this may influence metabolic reprogramming during tumorigenesis and stem cell reprogramming. With advances in subcellular proteomics it is likely that new roles for ERK1/2, and new substrates, remain to be discovered at the mitochondria and other organelles.
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Affiliation(s)
- Simon J. Cook
- Signalling ProgrammeThe Babraham InstituteCambridgeUK
| | - Kate Stuart
- Signalling ProgrammeThe Babraham InstituteCambridgeUK
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11
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Attenuation of the Type IV Pilus Retraction Motor Influences Neisseria gonorrhoeae Social and Infection Behavior. mBio 2016; 7:mBio.01994-16. [PMID: 27923924 PMCID: PMC5142622 DOI: 10.1128/mbio.01994-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Retraction of the type IV pilus (Tfp) mediates DNA uptake, motility, and social and infection behavior in a wide variety of prokaryotes. To date, investigations into Tfp retraction-dependent activities have used a mutant deleted of PilT, the ATPase motor protein that causes the pilus fiber to retract. ΔpilT cells are nontransformable, nonmotile, and cannot aggregate into microcolonies. We tested the hypothesis that these retraction-dependent activities are sensitive to the strength of PilT enzymatic activity by using the pathogen Neisseria gonorrhoeae as a model. We constructed an N. gonorrhoeae mutant with an amino acid substitution in the PilT Walker B box (a substitution of cysteine for leucine at position 201, encoded by pilTL201C). Purified PilTL201C forms a native hexamer, but mutant hexamers hydrolyze ATP at half the maximal rate. N. gonorrhoeae pilTL201C cells produce Tfp fibers, crawl at the same speed as the wild-type (wt) parent, and are equally transformable. However, the social behavior of pilTL201C cells is intermediate between the behaviors of wt and ΔpilT cells. The infection behavior of pilTL201C is also defective, due to its failure to activate the epidermal growth factor receptor (EGFR)-heparin-binding EGF-like growth factor (HB-EGF) pathway. Our study indicates that pilus retraction, per se, is not sufficient for N. gonorrhoeae microcolony formation or infectivity; rather, these activities are sensitive to the strength of PilT enzymatic activity. We discuss the implications of these findings for Neisseria pathogenesis in the context of mechanobiology. Type IV pili are fibers expressed on the surface of many bacteria. Neisseria gonorrhoeae cells crawl, take up DNA, and communicate with each other and with human cells by retracting these fibers. Here, we show that an N. gonorrhoeae mutant expressing an enzymatically weakened type IV pilus retraction motor still crawls and takes up DNA normally. However, mutant cells exhibit abnormal social behavior, and they are less infective because they fail to activate the epidermal growth factor receptor. Our study shows that N. gonorrhoeae social and infection behaviors are sensitive to the strength of the retraction motor enzyme.
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12
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Château A, Seifert HS. Neisseria gonorrhoeae survives within and modulates apoptosis and inflammatory cytokine production of human macrophages. Cell Microbiol 2016; 18:546-60. [PMID: 26426083 PMCID: PMC5240846 DOI: 10.1111/cmi.12529] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 09/17/2015] [Accepted: 09/28/2015] [Indexed: 12/28/2022]
Abstract
The human-adapted organism Neisseria gonorrhoeae is the causative agent of gonorrhoea, a sexually transmitted infection. It readily colonizes the genital, rectal and nasalpharyngeal mucosa during infection. While it is well established that N. gonorrhoeae recruits and modulates the functions of polymorphonuclear leukocytes during infection, how N. gonorrhoeae interacts with macrophages present in infected tissue is not fully defined. We studied the interactions of N. gonorrhoeae with two human monocytic cell lines, THP-1 and U937, and primary monocytes, all differentiated into macrophages. Most engulfed bacteria were killed in the phagolysosome, but a subset of bacteria was able to survive and replicate inside the macrophages suggesting that those cells may be an unexplored cellular reservoir for N. gonorrhoeae during infection. N. gonorrhoeae was able to modulate macrophage apoptosis: N. gonorrhoeae induced apoptosis in THP-1 cells whereas it inhibited induced apoptosis in U937 cells and primary human macrophages. Furthermore, N. gonorrhoeae induced expression of inflammatory cytokines in macrophages, suggesting a role for macrophages in recruiting polymorphonuclear leukocytes to the site of infection. These results indicate macrophages may serve as a significant replicative niche for N. gonorrhoeae and play an important role in gonorrheal pathogenesis.
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Affiliation(s)
- Alice Château
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
| | - H. Steven Seifert
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
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13
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Neisseria gonorrhoeae Modulates Cell Death in Human Endocervical Epithelial Cells through Export of Exosome-Associated cIAP2. Infect Immun 2015; 83:3410-7. [PMID: 26077759 DOI: 10.1128/iai.00732-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Indexed: 01/07/2023] Open
Abstract
Several bacterial pathogens persist and survive in the host by modulating host cell death pathways. We previously demonstrated that Neisseria gonorrhoeae, a Gram-negative pathogen responsible for the sexually transmitted infection gonorrhea, protects against exogenous induction of apoptosis in human cervical epithelial cells. However, induction of cell death by N. gonorrhoeae has also been reported in other cell types. The mechanisms by which N. gonorrhoeae modulates cell death are not clear, although a role for the inhibitor of apoptosis-2 (cIAP2) has been proposed. In this study, we confirmed that N. gonorrhoeae induces production of cIAP2 in human cervical epithelial cells. High levels of intracellular cIAP2 were detected early after N. gonorrhoeae stimulation, which was followed by a marked decrease at 24 h. At this time point, we observed increased levels of extracellular cIAP2 associated with exosomes and an overall increase in production of exosomes. Inhibition of cIAP2 in N. gonorrhoeae-stimulated epithelial cells resulted in increased cell death and interleukin-1β (IL-1β) production. Collectively these results indicate that N. gonorrhoeae stimulation of human endocervical epithelial cells induces the release of cIAP2, an essential regulator of cell death and immune signaling.
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14
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Liu GL, Parti RP, Dillon JAR. Suppression of ERK activation in urethral epithelial cells infected with Neisseria gonorrhoeae and its isogenic minD mutant contributes to anti-apoptosis. Microbes Infect 2014; 17:317-22. [PMID: 25554485 DOI: 10.1016/j.micinf.2014.12.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 12/15/2014] [Accepted: 12/17/2014] [Indexed: 10/24/2022]
Abstract
In gonococci-infected transduced human urethral epithelial cells (THUEC), the role of ERK, a mitogen-activated protein kinase (MAPK), in apoptosis is unknown. We observed lowering of ERK activation in THUEC following infection with anti-apoptosis-inducing Neisseria gonorrhoeae strain CH811. An isogenic cell division mutant of this strain, Ng CJSD1 (minD deficient), which is large and abnormally shaped, reduced ERK phosphorylation levels even more than its parental strain in THUEC. This led to higher anti-apoptosis in mutant-infected cells as compared to the parental strain-infected cells. Our results suggest that N. gonorrhoeae infection reduces ERK activation in THUEC contributing to anti-apoptosis.
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Affiliation(s)
- GuanQun L Liu
- Department of Biology, College of Arts and Science, University of Saskatchewan, W.P. Thompson Building 112 Science Place, Saskatoon, Saskatchewan, S7N5E2, Canada
| | - Rajinder P Parti
- Department of Biology, College of Arts and Science, University of Saskatchewan, W.P. Thompson Building 112 Science Place, Saskatoon, Saskatchewan, S7N5E2, Canada; Vaccine and Infectious Disease Organization-International Vaccine Center (VIDO-InterVac), University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, S7N5E3, Canada
| | - Jo-Anne R Dillon
- Department of Biology, College of Arts and Science, University of Saskatchewan, W.P. Thompson Building 112 Science Place, Saskatoon, Saskatchewan, S7N5E2, Canada; Vaccine and Infectious Disease Organization-International Vaccine Center (VIDO-InterVac), University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, S7N5E3, Canada; Department of Microbiology and Immunology, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, S7N5E5, Canada.
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15
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Mechanisms of apoptosis in irradiated and sunitinib-treated follicular thyroid cancer cells. Apoptosis 2014; 19:480-90. [PMID: 24213562 DOI: 10.1007/s10495-013-0937-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The multikinase inhibitor sunitinib (S) seems to have promising potential in the treatment of thyroid cancer. We focused on the impact of S and/or irradiation (R) on mechanisms of apoptosis in follicular thyroid cancer cells. The effects of R, S and their combination were evaluated 2 and 4 days after treatment, using the human thyroid cancer cell line CGTH W-1. The transcription of genes involved in the regulation of apoptosis was investigated using quantitative real-time PCR. Western blot analyses of caspases and survivin were also performed. S elevated BAX (day 4), CASP9, CASP3, BIRC5 (day 4) and PRKACA (day 4) gene expression, whereas the mRNAs of BCL2, CASP8, PRKCA, ERK1, and ERK2 were not significantly changed. S, R and R+S clearly induced caspase-9 protein and elevated caspase-3 activity. Survivin was down-regulated at day 4 in control cells and the expression was blunted by S treatment. R+S induced survivin expression at day 2 followed by a reduction at day 4 of treatment. Sunitinib and the combined application with radiation induced apoptosis in follicular thyroid cancer cells via the intrinsic pathway of apoptosis. In addition, sunitinib might induce apoptosis via decreased expression of the anti-apoptotic protein survivin. These findings suggest the potential use of sunitinib for the treatment of poorly differentiated follicular thyroid carcinomas.
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16
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Bim is a crucial regulator of apoptosis induced by Mycobacterium tuberculosis. Cell Death Dis 2014; 5:e1343. [PMID: 25032866 PMCID: PMC4123102 DOI: 10.1038/cddis.2014.313] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 06/13/2014] [Accepted: 06/17/2014] [Indexed: 02/03/2023]
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis, induces apoptosis in infected macrophages in vitro and in vivo. However, the molecular mechanism controlling this process is not known. In order to study the involvement of the mitochondrial apoptotic pathway in M. tuberculosis-induced apoptosis, we analysed cell death in M. tuberculosis-infected embryonic fibroblasts (MEFs) derived from different knockout mice for genes involved in this route. We found that apoptosis induced by M. tuberculosis is abrogated in the absence of Bak and Bax, caspase 9 or the executioner caspases 3 and 7. Notably, we show that MEF deficient in the BH3-only BCL-2-interacting mediator of cell death (Bim) protein were also resistant to this process. The relevance of these results has been confirmed in the mouse macrophage cell line J774, where cell transfection with siRNA targeting Bim impaired apoptosis induced by virulent mycobacteria. Notably, only infection with a virulent strain, but not with attenuated ESX-1-defective strains, such as Bacillus Calmette-Guerin and live-attenuated M. tuberculosis vaccine strain MTBVAC, induced Bim upregulation and apoptosis, probably implicating virulence factor early secreted antigenic target 6-kDa protein in this process. Our results suggest that Bim upregulation and apoptosis is mediated by the p38MAPK-dependent pathway. Our findings show that Bim is a master regulator of apoptosis induced by M. tuberculosis.
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17
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Real-time sensing of enteropathogenic E. coli-induced effects on epithelial host cell height, cell-substrate interactions, and endocytic processes by infrared surface plasmon spectroscopy. PLoS One 2013; 8:e78431. [PMID: 24194932 PMCID: PMC3806826 DOI: 10.1371/journal.pone.0078431] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 09/19/2013] [Indexed: 12/12/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) is an important, generally non-invasive, bacterial pathogen that causes diarrhea in humans. The microbe infects mainly the enterocytes of the small intestine. Here we have applied our newly developed infrared surface plasmon resonance (IR-SPR) spectroscopy approach to study how EPEC infection affects epithelial host cells. The IR-SPR experiments showed that EPEC infection results in a robust reduction in the refractive index of the infected cells. Assisted by confocal and total internal reflection microscopy, we discovered that the microbe dilates the intercellular gaps and induces the appearance of fluid-phase-filled pinocytic vesicles in the lower basolateral regions of the host epithelial cells. Partial cell detachment from the underlying substratum was also observed. Finally, the waveguide mode observed by our IR-SPR analyses showed that EPEC infection decreases the host cell's height to some extent. Together, these observations reveal novel impacts of the pathogen on the host cell architecture and endocytic functions. We suggest that these changes may induce the infiltration of a watery environment into the host cell, and potentially lead to failure of the epithelium barrier functions. Our findings also indicate the great potential of the label-free IR-SPR approach to study the dynamics of host-pathogen interactions with high spatiotemporal sensitivity.
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18
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Calton CM, Wade LK, So M. Upregulation of ATF3 inhibits expression of the pro-inflammatory cytokine IL-6 during Neisseria gonorrhoeae infection. Cell Microbiol 2013; 15:1837-50. [PMID: 23648135 DOI: 10.1111/cmi.12153] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 04/12/2013] [Accepted: 03/28/2013] [Indexed: 12/16/2022]
Abstract
Neisseria gonorrhoeae regulates the expression of epithelial cell genes, activates cytoprotective pathways in the infected cell and protects it from apoptosis. Many of these responses are enhanced by the Type IV pilus (Tfp). We tested the hypothesis that N. gonorrhoeae modulates the innate immune response by inducing expression of ATF3, a transcription factor that negatively regulates the expression of many cytokine genes. We further determined whether Tfp are involved in these events. We found that N. gonorrhoeae induces ATF3 expression in mucosal epithelial cells through activation of mitogen-activated protein kinases. Maximal ATF3 expression requires Tfp retraction. Knocking down endogenous levels of ATF3 results in higher levels of IL-6 transcript. Our findings strongly suggest that ATF3 is involved in suppressing cytokine expression during gonococcal infection. We propose a model for the role of ATF3 in the context of N. gonorrhoeae infection.
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Affiliation(s)
- Christine M Calton
- Department of Molecular Microbiology and Immunology, L220, Oregon Health and Science University, Portland, OR, 97239, USA; The BIO5 Institute, University of Arizona, Tucson, AZ, 85721, USA; Department of Immunobiology, University of Arizona, Tucson, AZ, 85721, USA
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19
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Affiliation(s)
- Lori L. Burrows
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8N 3Z5, Canada;
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20
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Massari P, Wetzler LM. Analysis of parameters associated with prevention of cellular apoptosis by pathogenic Neisseriae and purified porins. Methods Mol Biol 2012; 799:319-41. [PMID: 21993654 DOI: 10.1007/978-1-61779-346-2_19] [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] [Indexed: 06/19/2024]
Abstract
The process of cellular apoptosis is mediated by a number of microbial pathogens to modulate host defense mechanisms. Inhibition of apoptosis is thought to favor microbial survival, replication or immune evasion, while induction of apoptosis is likely to promote escape of the organisms from host cells. Several studies have reported that infection with Neisseria spp. can inhibit or reduce apoptotic cell death, thus allowing adaptation, intracellular replication, and immune evasion, events that are likely to spread infection. In this chapter, various techniques are described for direct measurement of host cell responses to infection with Neisseria meningitidis and to treatment with pure Neisseria porins, the major proteins found in the outer membrane of the pathogen.
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Affiliation(s)
- Paola Massari
- Department of Medicine, Evans BioMedical Research Center, Section of Infectious Diseases, Boston University School of Medicine, Boston, MA, USA.
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21
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Vielfort K, Söderholm N, Weyler L, Vare D, Löfmark S, Aro H. Neisseria gonorrhoeae infection causes DNA damage and affects the expression of p21, p27, and p53 in non-tumor epithelial cells. J Cell Sci 2012; 126:339-47. [DOI: 10.1242/jcs.117721] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The constant shedding and renewal of epithelial cells maintain the protection of epithelial barriers. Interference with the processes of host cell-cycle regulation and barrier integrity permits the bacterial pathogen Neisseria gonorrhoeae to effectively colonize and invade epithelial cells. Here, we show that a gonococcal infection causes DNA damage in human non-tumor vaginal VK2/E6E7 cells with an increase of 700 DNA strand breaks per cell per hour as detected by an alkaline DNA unwinding assay. Infected cells exhibited elevated levels of DNA double-strand breaks, as indicated by a more than 50% increase in cells expressing DNA damage-response protein 53BP1-positive foci that co-localized with phosphorylated histone H2AX (γH2AX). Furthermore, infected cells abolished their expression of the tumor protein p53 and induced an increase in the expression of cyclin-dependent kinase inhibitors p21 and p27 to 2.6-fold and 4.2-fold of controls, respectively. As shown by live-cell microscopy, flow cytometry assays, and BrdU incorporation assays, gonococcal infection slowed the host cell-cycle progression mainly by impairing progression through the G2 phase. Our findings show new cellular players that are involved in the control of the human cell cycle during gonococcal infection and the potential of bacteria to cause cellular abnormalities.
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22
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Neisseria gonorrhoeae-mediated inhibition of apoptotic signalling in polymorphonuclear leukocytes. Infect Immun 2011; 79:4447-58. [PMID: 21844239 DOI: 10.1128/iai.01267-10] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The human pathogen Neisseria gonorrhoeae recruits and interacts extensively with polymorphonuclear leukocytes (PMNs) during infection. N. gonorrhoeae is able to survive the bactericidal activity of these innate immune cells and can actively modulate PMN functions in vitro. PMNs are short-lived cells which readily undergo apoptosis, and thus the effect of N. gonorrhoeae infection on PMN survival has implications for whether PMNs might serve as an important site of bacterial replication during infection. We developed and validated an HL-60 myeloid leukemia cell culture model for PMN infection and used both these cells and primary PMNs to show that N. gonorrhoeae infection alone does not induce apoptosis and furthermore that N. gonorrhoeae can inhibit both spontaneous apoptosis and apoptosis induced by the intrinsic and extrinsic apoptosis inducers staurosporine (STS) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), respectively. N. gonorrhoeae infection also results in the activation of NF-κB signaling in neutrophils and induces secretion of an identical profile of proinflammatory cytokines and chemokines in both HL-60 cells and primary PMNs. Our data show that the HL-60 cell line can be used to effectively model N. gonorrhoeae-PMN interactions and that N. gonorrhoeae actively inhibits apoptosis induced by multiple stimuli to prolong PMN survival and potentially facilitate bacterial survival, replication, and transmission.
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23
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Swanson KV, Griffiss JM, Edwards VL, Stein DC, Song W. Neisseria gonorrhoeae-induced transactivation of EGFR enhances gonococcal invasion. Cell Microbiol 2011; 13:1078-90. [PMID: 21501367 DOI: 10.1111/j.1462-5822.2011.01603.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Neisseria gonorrhoeae, the causative agent of the sexually transmitted infection gonorrhoea, adheres to and invades into genital epithelial cells. Here, we investigate host components that are used by the bacteria for their entry into epithelial cells. We found that gonococcal microcolony formation on the surface of HEC-1-B cells disrupted the polarized, basolateral distribution of both epidermal growth factor receptor (EGFR) and ErbB2, a related family member, and induced their accumulation under the microcolonies at the apical membrane. Gonococcal infection increased EGFR and ErbB2 phosphorylation. The EGFR kinase inhibitor, AG1478, reduced gonococcal invasion by 80%, but had no effect on adherence or the recruitment of EGFR and ErbB2 to the microcolonies. Gonococcal inoculation upregulated the mRNA levels of several ligands of EGFR. Prevention of EGFR ligand shedding by blocking matrix metalloproteinase activation reduced gonococcal invasion without altering their adherence, while the addition of the EGFR ligand, HB-EGF, was able to restore invasion to 66% of control levels. These data indicate that N. gonorrhoeae modulates the activity and cellular distribution of host EGFR, facilitating their invasion. EGFR activation does not appear to be due to direct gonococcal binding to EGFR, but instead by its transactivation by gonococcal induced increases in EGFR ligands.
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Affiliation(s)
- Karen V Swanson
- Department of Cell Biology & Molecular Genetics, and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, USA
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24
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Zahavi EE, Lieberman JA, Donnenberg MS, Nitzan M, Baruch K, Rosenshine I, Turner JR, Melamed-Book N, Feinstein N, Zlotkin-Rivkin E, Aroeti B. Bundle-forming pilus retraction enhances enteropathogenic Escherichia coli infectivity. Mol Biol Cell 2011; 22:2436-47. [PMID: 21613538 PMCID: PMC3135470 DOI: 10.1091/mbc.e11-01-0001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) and other pathogenic bacteria use dynamic type IV pili to adhere to the host. Here we show that the capacity of the EPEC type IV pili to retract is required for the breakdown of the host epithelial tight-junction barrier, efficient actin-pedestal formation, and translocation of effectors via the type III secretion system. Enteropathogenic Escherichia coli (EPEC) is an important human pathogen that causes acute infantile diarrhea. The type IV bundle-forming pili (BFP) of typical EPEC strains are dynamic fibrillar organelles that can extend out and retract into the bacterium. The bfpF gene encodes for BfpF, a protein that promotes pili retraction. The BFP are involved in bacterial autoaggregation and in mediating the initial adherence of the bacterium with its host cell. Importantly, BFP retraction is implicated in virulence in experimental human infection. How pili retraction contributes to EPEC pathogenesis at the cellular level remains largely obscure, however. In this study, an effort has been made to address this question using engineered EPEC strains with induced BFP retraction capacity. We show that the retraction is important for tight-junction disruption and, to a lesser extent, actin-rich pedestal formation by promoting efficient translocation of bacterial protein effectors into the host cells. A model is proposed whereby BFP retraction permits closer apposition between the bacterial and the host cell surfaces, thus enabling timely and effective introduction of bacterial effectors into the host cell via the type III secretion apparatus. Our studies hence suggest novel insights into the involvement of pili retraction in EPEC pathogenesis.
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Affiliation(s)
- Eitan E Zahavi
- Department of Cell and Developmental Biology, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Dietrich M, Bartfeld S, Munke R, Lange C, Ogilvie LA, Friedrich A, Meyer TF. Activation of NF-κB by Neisseria gonorrhoeae is associated with microcolony formation and type IV pilus retraction. Cell Microbiol 2011; 13:1168-82. [PMID: 21615661 DOI: 10.1111/j.1462-5822.2011.01607.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The early stage of infection with Neisseria gonorrhoeae (Ngo), the causative agent of gonorrhoea, is marked by type IV pilus (Tfp)-mediated attachment and the formation of bacterial microcolonies on epithelial cells. Retraction of the Ngo Tfp generates substantial force on its substrate which can elicit host cell signalling. Here, we observed that this retraction force could also activate nuclear factor (NF)-κB, the central signalling cascade of innate immunity. Using a p65-GFP-expressing epithelial cell line, we show that piliated Ngo induce asynchronous NF-κB activation in infected cells, which is temporally associated with the formation of gonococcal microcolonies. A mutant lacking PilT, an ATPase necessary for Tfp retraction, induced markedly reduced NF-κB activation. This was accompanied by decreased NF-κB target gene transcription and cytokine release. The impaired ability of the pilT mutant to activate NF-κB was compensated by applying mechanical shear stress to the infected host cells, indicating that the mechanical forces generated by retractile pili are involved in the retraction-dependent activation of NF-κB elicited by gonococcal microcolonies. Thus, our work provides evidence for an intriguing relationship between microcolony growth, pilus retraction and host cell signalling, with likely implications with regard to the course of symptomatic versus asymptomatic gonococcal infections.
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Affiliation(s)
- Manuela Dietrich
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
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26
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Guo X, Roberts MR, Becker SM, Podd B, Zhang Y, Chua SC, Myers MG, Duggal P, Houpt ER, Petri WA. Leptin signaling in intestinal epithelium mediates resistance to enteric infection by Entamoeba histolytica. Mucosal Immunol 2011; 4:294-303. [PMID: 21124310 PMCID: PMC3079783 DOI: 10.1038/mi.2010.76] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Leptin is an adipocytokine that links nutrition to immunity. Previous observation that a genetic polymorphism in the leptin receptor affected susceptibility to Entamoeba histolytica infection led to the hypothesis that leptin signaling has a protective role during intestinal amebic infection. In this study we show that mice lacking the functional leptin receptor developed devastating mucosal destruction after E. histolytica infection. Bone marrow chimera experiments demonstrated that leptin receptor expressed on hematopoietic cells was not sufficient to confer resistance. Similarly, peripheral knockout of the leptin receptor rendered animals susceptible, indicating that central expression of the leptin receptor was not sufficient to confer protection. The site of leptin action was localized to the gut via an intestinal epithelium-specific deletion of the leptin receptor, which rendered mice susceptible to infection and mucosal destruction by the parasite. Mutation of tyrosine 985 or 1138 in the intracellular domain of the leptin receptor, which mediates signaling through the SH2-containing tyrosine phosphatase/extracellular signal-regulated kinase (SHP2/ERK) and signal transducer and activator of transcription 3 (STAT3) pathways, respectively, demonstrated that both were important for mucosal protection. We conclude that leptin-mediated resistance to amebiasis is via its actions on intestinal epithelium rather than hematopoietic cells or the brain, and requires leptin receptor signaling through both the STAT3 and SHP2/ERK pathways.
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Affiliation(s)
- Xiaoti Guo
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| | - Margo R. Roberts
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| | - Stephen M. Becker
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| | - Bradley Podd
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| | - Yiying Zhang
- Department of Pediatrics, Division of Molecular Genetics & Naomi Berrie Diabetes Center Columbia University Medical Center, New York, New York
| | - Streamson C. Chua
- Departments of Medicine and Neuroscience, Albert Einstein College of Medicine, Bronx, New York
| | - Martin G. Myers
- Departments of Internal Medicine & Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Priya Duggal
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Eric R. Houpt
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia.,Corresponding Authors: William A. Petri, Jr., Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, 434 924 5621 (direct), 434 924 0075 (fax) , *Eric R. Houpt, Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, 434 243 9326 (direct), 434 924 0075 (fax)
| | - William A. Petri
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
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Kim M, Ashida H, Ogawa M, Yoshikawa Y, Mimuro H, Sasakawa C. Bacterial interactions with the host epithelium. Cell Host Microbe 2010; 8:20-35. [PMID: 20638639 DOI: 10.1016/j.chom.2010.06.006] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 04/03/2010] [Accepted: 04/27/2010] [Indexed: 12/14/2022]
Abstract
The gastrointestinal epithelium deploys multiple innate defense mechanisms to fight microbial intruders, including epithelial integrity, rapid epithelial cell turnover, quick expulsion of infected cells, autophagy, and innate immune responses. Nevertheless, many bacterial pathogens are equipped with highly evolved infectious stratagems that circumvent these defense systems and use the epithelium as a replicative foothold. During replication on and within the gastrointestinal epithelium, gastrointestinal bacterial pathogens secrete various components, toxins, and effectors that can subvert, usurp, and exploit host cellular functions to benefit bacterial survival. In addition, bacterial pathogens use a variety of mechanisms that balance breaching the epithelial barrier with maintaining the epithelium in order to promote bacterial colonization. These complex strategies represent a new paradigm of bacterial pathogenesis.
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Affiliation(s)
- Minsoo Kim
- Department of Infectious Disease Control, International Research Center for Infectious Diseases, University of Tokyo 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
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28
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Interactions between bacterial pathogens and mitochondrial cell death pathways. Nat Rev Microbiol 2010; 8:693-705. [PMID: 20818415 DOI: 10.1038/nrmicro2421] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The modulation of host cell death pathways by bacteria has been recognized as a major pathogenicity mechanism. Among other strategies, bacterial pathogens can hijack the cell death machinery of host cells by influencing the signalling pathways that converge on the mitochondria. In particular, many bacterial proteins have evolved to interact in a highly specific manner with host mitochondria, thereby modulating the decision between cell life and death. In this Review, we explore the intimate interactions between bacterial pathogens and mitochondrial cell death pathways.
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29
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Meningococcal porin PorB prevents cellular apoptosis in a toll-like receptor 2- and NF-kappaB-independent manner. Infect Immun 2009; 78:994-1003. [PMID: 20028813 DOI: 10.1128/iai.00156-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Meningococcal porin PorB is an inhibitor of apoptosis induced via the intrinsic pathway in various cell types. This effect is attributed to prevention of mitochondrial depolarization and of subsequent release of proapoptotic mitochondrial factors. To determine whether apoptosis is globally inhibited by PorB, we compared the intrinsic and extrinsic pathways in HeLa cells. Interestingly, PorB does not prevent extrinsic apoptosis induced by tumor necrosis factor alpha plus cycloheximide, suggesting a unique mitochondrial pathway specificity. Several intracellular factors regulated by NF-kappaB, including members of the Bcl-2 family and of the inhibitor of apoptosis (IAP) family, play major roles in controlling apoptosis, and some of them are thought to contribute to the antiapoptotic effect of the gonococcal porin, PIB. However, most of the members of the Bcl-2 family and the IAP family are not induced by meningococcal PorB in HeLa cells, with the exception of Bfl-1/A1. Interestingly, PorB does not induce NF-kappaB activation in HeLa cells, likely due to a lack of Toll-like receptor 2 (TLR2) expression in these cells. Bfl-1/A1 expression is also regulated by CBF1, a nuclear component of the Notch signaling pathway, independent of NF-kappaB activation. Since HeLa cells are protected by PorB from intrinsic apoptosis events, regardless of TLR2 and NF-kappaB expression, the possibility of a contribution of alternative signaling pathways to this effect cannot be excluded. In this paper, we describe an initial dissection of the cascade of cellular events involved in the antiapoptotic effect of PorB in the absence of TLR2.
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30
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Weyand NJ, Calton CM, Higashi DL, Kanack KJ, So M. Presenilin/gamma-secretase cleaves CD46 in response to Neisseria infection. THE JOURNAL OF IMMUNOLOGY 2009; 184:694-701. [PMID: 20018629 DOI: 10.4049/jimmunol.0900522] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CD46 is a type I transmembrane protein with complement and T cell regulatory functions in human cells. CD46 has signaling and receptor properties in immune and nonimmune cells, many of which are dependent on the expression of cytoplasmic tail (cyt) isoforms cyt1 or cyt2. Little is known about how cyt1 and cyt2 mediate cellular responses. We show that CD46-cyt1 and CD46-cyt2 are substrates for presenilin/gamma-secretase (PS/gammaS), an endogenous protease complex that regulates many important signaling proteins through proteolytic processing. PS/gammaS processing of CD46 releases immunoprecipitable cyt1 and cyt2 tail peptides into the cell, is blocked by chemical inhibitors, and is prevented in dominant negative presenilin mutant cell lines. Two human pathogens, Neisseria gonorrhoeae and Neisseria meningitidis, stimulate PS/gammaS processing of CD46-cyt1 and CD46-cyt2. This stimulation requires type IV pili and PilT, the type IV pilus retraction motor, implying that mechanotransduction plays a role in this event. We present a model for PS/gammaS processing of CD46 that provides a mechanism by which signals are transduced via the cyt1 and cyt2 tails to regulate CD46-dependent cellular responses. Our findings have broad implications for understanding the full range of CD46 functions in infection and noninfection situations.
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Affiliation(s)
- Nathan J Weyand
- BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA.
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31
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Higashi DL, Zhang GH, Biais N, Myers LR, Weyand NJ, Elliott DA, So M. Influence of type IV pilus retraction on the architecture of the Neisseria gonorrhoeae-infected cell cortex. MICROBIOLOGY-SGM 2009; 155:4084-4092. [PMID: 19762436 DOI: 10.1099/mic.0.032656-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Early in infection, Neisseria gonorrhoeae can be observed to attach to the epithelial cell surface as microcolonies and induce dramatic changes to the host cell cortex. We tested the hypothesis that type IV pili (Tfp) retraction plays a role in the ultrastructure of both the host cell cortex and the bacterial microcolony. Using serial ultrathin sectioning, transmission electron microscopy and 3D reconstruction of serial 2D images, we have obtained what we believe to be the first 3D reconstructions of the N. gonorrhoeae-host cell interface, and determined the architecture of infected cell microvilli as well as the attached microcolony. Tfp connect both wild-type (wt) and Tfp retraction-deficient bacteria with each other, and with the host cell membrane. Tfp fibres and microvilli form a lattice in the wt microcolony and at its periphery. Wt microcolonies induce microvilli formation and increases of surface area, leading to an approximately ninefold increase in the surface area of the host cell membrane at the site of attachment. In contrast, Tfp retraction-deficient microcolonies do not affect these parameters. Wt microcolonies had a symmetrical, dome-shaped structure with a circular 'footprint', while Tfp retraction-deficient microcolonies were notably less symmetrical. These findings support a major role for Tfp retraction in microvilli and microcolony architecture. They are consistent with the biophysical attributes of Tfp and the effects of Tfp retraction on epithelial cell signalling.
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Affiliation(s)
- Dustin L Higashi
- Department of Immunobiology and the BIO5 Institute, University of Arizona, Tucson, AZ, USA
| | - Gina H Zhang
- Department of Cell Biology and Anatomy, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Nicolas Biais
- Department of Biological Sciences, Columbia University, New York, USA
| | - Lauren R Myers
- Department of Immunobiology and the BIO5 Institute, University of Arizona, Tucson, AZ, USA
| | - Nathan J Weyand
- Department of Immunobiology and the BIO5 Institute, University of Arizona, Tucson, AZ, USA
| | - David A Elliott
- Department of Cell Biology and Anatomy, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Magdalene So
- Department of Immunobiology and the BIO5 Institute, University of Arizona, Tucson, AZ, USA
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32
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Kline KA, Fälker S, Dahlberg S, Normark S, Henriques-Normark B. Bacterial adhesins in host-microbe interactions. Cell Host Microbe 2009; 5:580-92. [PMID: 19527885 DOI: 10.1016/j.chom.2009.05.011] [Citation(s) in RCA: 414] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 05/23/2009] [Accepted: 05/27/2009] [Indexed: 02/09/2023]
Abstract
Most commensal and pathogenic bacteria interacting with eukaryotic hosts express adhesive molecules on their surfaces that promote interaction with host cell receptors or with soluble macromolecules. Even though bacterial attachment to epithelial cells may be beneficial for bacterial colonization, adhesion may come at a cost because bacterial attachment to immune cells can facilitate phagocytosis and clearing. Many pathogenic bacteria have solved this dilemma by producing an antiphagocytic surface layer usually consisting of polysaccharide and by expressing their adhesins on polymeric structures that extend out from the cell surface. In this review, we will focus on the interaction between bacterial adhesins and the host, with an emphasis on pilus-like structures.
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Affiliation(s)
- Kimberly A Kline
- Swedish Institute for Infectious Disease Control and Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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Neisseria gonorrhoeae infection protects human endocervical epithelial cells from apoptosis via expression of host antiapoptotic proteins. Infect Immun 2009; 77:3602-10. [PMID: 19546192 DOI: 10.1128/iai.01366-08] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Several microbial pathogens can modulate the host apoptotic response to infection, which may contribute to immune evasion. Various studies have reported that infection with the sexually transmitted disease pathogen Neisseria gonorrhoeae can either inhibit or induce apoptosis. N. gonorrhoeae infection initiates at the mucosal epithelium, and in women, cells from the ectocervix and endocervix are among the first host cells encountered by this pathogen. In this study, we defined the antiapoptotic effect of N. gonorrhoeae infection in human endocervical epithelial cells (End/E6E7 cells). We first established that N. gonorrhoeae strain FA1090B failed to induce cell death in End/E6E7 cells. Subsequently, we demonstrated that stimulation with N. gonorrhoeae protected these cells from staurosporine (STS)-induced apoptosis. Importantly, only End/E6E7 cells incubated with live bacteria and in direct association with N. gonorrhoeae were protected from STS-induced apoptosis, while heat-killed and antibiotic-killed bacteria failed to induce protection. Stimulation of End/E6E7 cells with live N. gonorrhoeae induced NF-kappaB activation and resulted in increased gene expression of the NF-kappaB-regulated antiapoptotic genes bfl-1, cIAP-2, and c-FLIP. Furthermore, cIAP-2 protein levels also increased in End/E6E7 cells incubated with gonococci. Collectively, our results indicate that the antiapoptotic effect of N. gonorrhoeae in human endocervical epithelial cells results from live infection via expression of host antiapoptotic proteins. Securing an intracellular niche through the inhibition of apoptosis may be an important mechanism utilized by N. gonorrhoeae for microbial survival and immune evasion in cervical epithelial cells.
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Dietrich M, Mollenkopf H, So M, Friedrich A. Pilin regulation in the pilT mutant of Neisseria gonorrhoeae strain MS11. FEMS Microbiol Lett 2009; 296:248-56. [PMID: 19486161 DOI: 10.1111/j.1574-6968.2009.01647.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The ATPase protein PilT mediates retraction of type IV pili (Tfp). Tfp retraction of Neisseria gonorrhoeae causes many signal transduction events and changes in gene expression in infected epithelial cells. To find out whether a pilT mutation and lack of Tfp retraction, respectively, lead also to gene regulation in bacteria, we performed microarrays comparing the transcriptional profiles of the N. gonorrhoeae parent strain MS11 and its isogenic pilT mutant during growth in vitro. A loss-of-function-mutation in pilT led to altered transcript levels of 63 ORFs. Levels of pilE transcripts and its deduced protein, the major Tfp subunit pilin, were increased most markedly by a mutation in pilT. Further studies revealed that pilE expression was also controlled by two other genes encoding Tfp biogenesis proteins, pilD and pilF. Our studies strongly suggest that pilE expression is a finely tuned process.
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Affiliation(s)
- Manuela Dietrich
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
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35
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Kepp O, Gottschalk K, Churin Y, Rajalingam K, Brinkmann V, Machuy N, Kroemer G, Rudel T. Bim and Bmf synergize to induce apoptosis in Neisseria gonorrhoeae infection. PLoS Pathog 2009; 5:e1000348. [PMID: 19300516 PMCID: PMC2654407 DOI: 10.1371/journal.ppat.1000348] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Accepted: 02/25/2009] [Indexed: 11/18/2022] Open
Abstract
Bcl-2 family proteins including the pro-apoptotic BH3-only proteins are central regulators of apoptotic cell death. Here we show by a focused siRNA miniscreen that the synergistic action of the BH3-only proteins Bim and Bmf is required for apoptosis induced by infection with Neisseria gonorrhoeae (Ngo). While Bim and Bmf were associated with the cytoskeleton of healthy cells, they both were released upon Ngo infection. Loss of Bim and Bmf from the cytoskeleton fraction required the activation of Jun-N-terminal kinase-1 (JNK-1), which in turn depended on Rac-1. Depletion and inhibition of Rac-1, JNK-1, Bim, or Bmf prevented the activation of Bak and Bax and the subsequent activation of caspases. Apoptosis could be reconstituted in Bim-depleted and Bmf-depleted cells by additional silencing of antiapoptotic Mcl-1 and Bcl-XL, respectively. Our data indicate a synergistic role for both cytoskeletal-associated BH3-only proteins, Bim, and Bmf, in an apoptotic pathway leading to the clearance of Ngo-infected cells. A variety of physiological death signals, as well as pathological insults, trigger apoptosis, a genetically programmed form of cell death. Pathogens often induce host cell apoptosis to establish a successful infection. Neisseria gonorrhoeae (Ngo), the etiological agent of the sexually transmitted disease gonorrhoea, is a highly adapted obligate human-specific pathogen and has been shown to induce apoptosis in infected cells. Here we unveil the molecular mechanisms leading to apoptosis of infected cells. We show that Ngo-mediated apoptosis requires a special subset of proapoptotic proteins from the group of BH3-only proteins. BH3-only proteins act as stress sensors to translate toxic environmental signals to the initiation of apoptosis. In a siRNA-based miniscreen, we found Bim and Bmf, BH3-only proteins associated with the cytoskeleton, necessary to induce host cell apoptosis upon infection. Bim and Bmf inactivated different inhibitors of apoptosis and thereby induced cell death in response to infection. Our data unveil a novel pathway of infection-induced apoptosis that enhances our understanding of the mechanism by which BH3-only proteins control apoptotic cell death.
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Affiliation(s)
- Oliver Kepp
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Kathleen Gottschalk
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Yuri Churin
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Krishnaraj Rajalingam
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Volker Brinkmann
- Core Facility for Microscopy, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Nikolaus Machuy
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Guido Kroemer
- INSERM, U848, Institute Gustave Roussy, Université Paris Sud, Paris, France
| | - Thomas Rudel
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
- Biozentrum, University of Würzburg, Department of Microbiology, Würzburg, Germany
- * E-mail:
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36
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Sustained activation of Akt and Erk1/2 is required for Coxiella burnetii antiapoptotic activity. Infect Immun 2008; 77:205-13. [PMID: 18981248 DOI: 10.1128/iai.01124-08] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Coxiella burnetii is an obligate intracellular bacterial pathogen that directs biogenesis of a lysosome-like, parasitophorous vacuole in mammalian cells. We recently reported that C. burnetii inhibits apoptotic cell death in macrophages, presumably as a mechanism to sustain the host for completion of its lengthy infectious cycle. In the current study, we further investigated C. burnetii manipulation of host cell signaling and apoptosis by examining the effect of C. burnetii infection on activation of 15 host proteins involved in stress responses, cytokine production, and apoptosis. C. burnetii infection of THP-1 human macrophage-like cells caused increased levels of phosphorylated c-Jun, Hsp27, Jun N-terminal protein kinase, and p38 at 2 h postinfection (hpi), and this activation rapidly decreased to near basal levels by 24 hpi. The prosurvival kinases Akt and Erk1/2 (extracellular signal-regulated kinases 1 and 2) were also activated at 2 to 6 hpi; however, the phosphorylation of these proteins increased coincident with C. burnetii replication through at least 72 hpi. Sustained phosphorylation of Akt and Erk1/2 was abolished by treatment of infected cells with rifampin, indicating their activation is a C. burnetii-directed event requiring pathogen RNA synthesis. Moreover, pharmacological inhibition of Akt or Erk1/2 significantly decreased C. burnetii antiapoptotic activity. Collectively, these results indicate the importance of C. burnetii modulation of host signaling and demonstrate a critical role for Akt and Erk1/2 in successful intracellular parasitism and maintenance of host cell viability.
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