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Denny JE, Alam MZ, Mdluli NV, Maslanka JR, Lieberman LA, Abt MC. Monoclonal antibody-mediated neutralization of Clostridioides difficile toxin does not diminish induction of the protective innate immune response to infection. Anaerobe 2024; 88:102859. [PMID: 38701911 PMCID: PMC11347114 DOI: 10.1016/j.anaerobe.2024.102859] [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: 12/21/2023] [Revised: 04/18/2024] [Accepted: 04/24/2024] [Indexed: 05/05/2024]
Abstract
Clostridioides difficile infection causes pathology that ranges in severity from diarrhea to pseudomembranous colitis. Toxin A and Toxin B are the two primary virulence factors secreted by C. difficile that drive disease severity. The toxins damage intestinal epithelial cells leading to a loss of barrier integrity and induction of a proinflammatory host response. Monoclonal antibodies (mAbs) that neutralize Toxin A and Toxin B, actoxumab and bezlotoxumab, respectively, significantly reduce disease severity in a murine model of C. difficile infection. However, the impact of toxin neutralization on the induction and quality of the innate immune response following infection is unknown. The goal of this study was to define the quality of the host innate immune response in the context of anti-toxin mAbs therapy. At day 2 post-infection, C. difficile-infected, mAbs-treated mice had significantly less disease compared to isotype-treated mice despite remaining colonized with C. difficile. C. difficile-infected mAbs-treated mice still exhibited marked neutrophil infiltration and induction of a subset of proinflammatory cytokines within the intestinal lamina propria following infection that is comparable to isotype-treated mice. Furthermore, both mAbs and isotype-treated mice had an increase in IL-22-producing ILCs in the intestine following infection. MAbs-treated mice exhibited increased infiltration of eosinophils in the intestinal lamina propria, which has been previously reported to promote a protective host response following C. difficile infection. These findings show that activation of host protective mechanisms remain intact in the context of monoclonal antibody-mediated toxin neutralization.
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Affiliation(s)
- Joshua E Denny
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Md Zahidul Alam
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nontokozo V Mdluli
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jeffrey R Maslanka
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Michael C Abt
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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2
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Pourliotopoulou E, Karampatakis T, Kachrimanidou M. Exploring the Toxin-Mediated Mechanisms in Clostridioides difficile Infection. Microorganisms 2024; 12:1004. [PMID: 38792835 PMCID: PMC11124097 DOI: 10.3390/microorganisms12051004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 05/14/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
Clostridioides difficile infection (CDI) is the leading cause of nosocomial antibiotic-associated diarrhea, and colitis, with increasing incidence and healthcare costs. Its pathogenesis is primarily driven by toxins produced by the bacterium C. difficile, Toxin A (TcdA) and Toxin B (TcdB). Certain strains produce an additional toxin, the C. difficile transferase (CDT), which further enhances the virulence and pathogenicity of C. difficile. These toxins disrupt colonic epithelial barrier integrity, and induce inflammation and cellular damage, leading to CDI symptoms. Significant progress has been made in the past decade in elucidating the molecular mechanisms of TcdA, TcdB, and CDT, which provide insights into the management of CDI and the future development of novel treatment strategies based on anti-toxin therapies. While antibiotics are common treatments, high recurrence rates necessitate alternative therapies. Bezlotoxumab, targeting TcdB, is the only available anti-toxin, yet limitations persist, prompting ongoing research. This review highlights the current knowledge of the structure and mechanism of action of C. difficile toxins and their role in disease. By comprehensively describing the toxin-mediated mechanisms, this review provides insights for the future development of novel treatment strategies and the management of CDI.
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Affiliation(s)
- Evdokia Pourliotopoulou
- Department of Microbiology, Medical School, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;
| | | | - Melania Kachrimanidou
- Department of Microbiology, Medical School, Aristotle University of Thessaloniki, 541 24 Thessaloniki, Greece;
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3
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Liao X, Liu J, Guo X, Meng R, Zhang W, Zhou J, Xie X, Zhou H. Origin and Function of Monocytes in Inflammatory Bowel Disease. J Inflamm Res 2024; 17:2897-2914. [PMID: 38764499 PMCID: PMC11100499 DOI: 10.2147/jir.s450801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 04/23/2024] [Indexed: 05/21/2024] Open
Abstract
Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is a chronic disease resulting from the interaction of various factors such as social elements, autoimmunity, genetics, and gut microbiota. Alarmingly, recent epidemiological data points to a surging incidence of IBD, underscoring an urgent imperative: to delineate the intricate mechanisms driving its onset. Such insights are paramount, not only for enhancing our comprehension of IBD pathogenesis but also for refining diagnostic and therapeutic paradigms. Monocytes, significant immune cells derived from the bone marrow, serve as precursors to macrophages (Mφs) and dendritic cells (DCs) in the inflammatory response of IBD. Within the IBD milieu, their role is twofold. On the one hand, monocytes are instrumental in precipitating the disease's progression. On the other hand, their differentiated offsprings, namely moMφs and moDCs, are conspicuously mobilized at inflammatory foci, manifesting either pro-inflammatory or anti-inflammatory actions. The phenotypic spectrum of these effector cells, intriguingly, is modulated by variables such as host genetics and the subtleties of the prevailing inflammatory microenvironment. Notwithstanding their significance, a palpable dearth exists in the literature concerning the roles and mechanisms of monocytes in IBD pathogenesis. This review endeavors to bridge this knowledge gap. It offers an exhaustive exploration of monocytes' origin, their developmental trajectory, and their differentiation dynamics during IBD. Furthermore, it delves into the functional ramifications of monocytes and their differentiated progenies throughout IBD's course. Through this lens, we aspire to furnish novel perspectives into IBD's etiology and potential therapeutic strategies.
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Affiliation(s)
- Xiping Liao
- Clinical Medical Research Center, the Second Affiliated Hospital, Army Medical University, Chongqing, People’s Republic of China
- Department of Gastroenterology, the Second Affiliated Hospital, Army Medical University, Chongqing, People’s Republic of China
| | - Ji Liu
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Guangzhou, People’s Republic of China
| | - Xiaolong Guo
- Clinical Medical Research Center, the Second Affiliated Hospital, Army Medical University, Chongqing, People’s Republic of China
| | - Ruiping Meng
- Clinical Medical Research Center, the Second Affiliated Hospital, Army Medical University, Chongqing, People’s Republic of China
| | - Wei Zhang
- Clinical Medical Research Center, the Second Affiliated Hospital, Army Medical University, Chongqing, People’s Republic of China
| | - Jianyun Zhou
- Clinical Medical Research Center, the Second Affiliated Hospital, Army Medical University, Chongqing, People’s Republic of China
| | - Xia Xie
- Clinical Medical Research Center, the Second Affiliated Hospital, Army Medical University, Chongqing, People’s Republic of China
- Department of Gastroenterology, the Second Affiliated Hospital, Army Medical University, Chongqing, People’s Republic of China
| | - Hongli Zhou
- Clinical Medical Research Center, the Second Affiliated Hospital, Army Medical University, Chongqing, People’s Republic of China
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4
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Wang W, Liu Y, Yao Z, Chen D, Tang Y, Cui J, Zhang J, Liu H, Hao Z. A microfluidic-based gut-on-a-chip model containing the gut microbiota of patients with depression reveals physiological characteristics similar to depression. LAB ON A CHIP 2024; 24:2537-2550. [PMID: 38623757 DOI: 10.1039/d3lc01052j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
The diverse commensal microbiome of the human intestine has been considered to play a central role in depression. However, no host-microbiota co-culture system has been developed for depression, which hinders the controlled study of the interaction between depression and gut microbiota. We designed and manufactured a microfluidic-based gut-on-a-chip model containing the gut microbiota of patients with depression (depression-on-gut-chip, DoGC), which enables the extended co-culture of viable aerobic human intestinal epithelial cells and anaerobic gut microbiota, and allows the direct study of interactions between human gut microbiota and depression. We introduced representative gut microbiota from individuals with depression into our constructed DoGC model, successfully recapitulating the gut microbiota structure of depressed patients. This further led to the manifestation of physiological characteristics resembling depression, such as reduced gut barrier function, chronic low-grade inflammatory responses and decreased neurotransmitter 5-HT levels. Metabolome analysis of substances in the DoGC revealed a significant increase in lipopolysaccharides and tyrosine, while hyodeoxycholic acid, L-proline and L-threonine were significantly reduced, indicating the occurrence of depression. The proposed DoGC can serve as an effective platform for studying the gut microbiota of patients with depression, providing important cues for their roles in the pathology of this condition and acting as a powerful tool for personalized medicine.
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Affiliation(s)
- Wenxin Wang
- Institute of Environmental Biology and Life Support Technology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Yiyuan Liu
- Institute of Environmental Biology and Life Support Technology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Zhikai Yao
- Institute of Environmental Biology and Life Support Technology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Dengbo Chen
- Institute of Environmental Biology and Life Support Technology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Yue Tang
- Key Laboratory of Molecular Medicine and Biotherapy, The Ministry of Industry and Information Technology, School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
| | - Jingwei Cui
- Institute of Environmental Biology and Life Support Technology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Jiangjiang Zhang
- Key Laboratory of Molecular Medicine and Biotherapy, The Ministry of Industry and Information Technology, School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
| | - Hong Liu
- Institute of Environmental Biology and Life Support Technology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Zikai Hao
- Key Laboratory of Molecular Medicine and Biotherapy, The Ministry of Industry and Information Technology, School of Life Science, Beijing Institute of Technology, Beijing 100081, China.
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5
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Papatheodorou P, Minton NP, Aktories K, Barth H. An Updated View on the Cellular Uptake and Mode-of-Action of Clostridioides difficile Toxins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1435:219-247. [PMID: 38175478 DOI: 10.1007/978-3-031-42108-2_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Research on the human gut pathogen Clostridioides (C.) difficile and its toxins continues to attract much attention as a consequence of the threat to human health posed by hypervirulent strains. Toxin A (TcdA) and Toxin B (TcdB) are the two major virulence determinants of C. difficile. Both are single-chain proteins with a similar multidomain architecture. Certain hypervirulent C. difficile strains also produce a third toxin, namely binary toxin CDT (C. difficile transferase). C. difficile toxins are the causative agents of C. difficile-associated diseases (CDADs), such as antibiotics-associated diarrhea and pseudomembranous colitis. For that reason, considerable efforts have been expended to unravel their molecular mode-of-action and the cellular mechanisms responsible for their uptake. Many of these studies have been conducted in European laboratories. Here, we provide an update on our previous review (Papatheodorou et al. Adv Exp Med Biol, 2018) on important advances in C. difficile toxins research.
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Affiliation(s)
- Panagiotis Papatheodorou
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany.
| | - Nigel P Minton
- BBSRC/EPSRC Synthetic Biology Research Centre, University of Nottingham, Nottingham, UK
| | - Klaus Aktories
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Freiburg, Freiburg, Germany
| | - Holger Barth
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, Ulm University Medical Center, Ulm, Germany
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6
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Alam MZ, Markantonis JE, Fallon JT. Host Immune Responses to Clostridioides difficile Infection and Potential Novel Therapeutic Approaches. Trop Med Infect Dis 2023; 8:506. [PMID: 38133438 PMCID: PMC10747268 DOI: 10.3390/tropicalmed8120506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/17/2023] [Accepted: 11/19/2023] [Indexed: 12/23/2023] Open
Abstract
Clostridioides difficile infection (CDI) is a leading nosocomial infection, posing a substantial public health challenge within the United States and globally. CDI typically occurs in hospitalized elderly patients who have been administered antibiotics; however, there has been a rise in the occurrence of CDI in the community among young adults who have not been exposed to antibiotics. C. difficile releases toxins, which damage large intestinal epithelium, leading to toxic megacolon, sepsis, and even death. Unfortunately, existing antibiotic therapies do not always prevent these consequences, with up to one-third of treated patients experiencing a recurrence of the infection. Host factors play a crucial role in the pathogenesis of CDI, and accumulating evidence shows that modulation of host immune responses may potentially alter the disease outcome. In this review, we provide an overview of our current knowledge regarding the role of innate and adaptive immune responses on CDI outcomes. Moreover, we present a summary of non-antibiotic microbiome-based therapies that can effectively influence host immune responses, along with immunization strategies that are intended to tackle both the treatment and prevention of CDI.
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Affiliation(s)
- Md Zahidul Alam
- Department of Pathology and Laboratory Medicine, Brody School of Medicine, East Carolina University, 600 Moye Boulevard, Greenville, NC 27834, USA; (J.E.M.); (J.T.F.)
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7
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Fettucciari K, Dini F, Marconi P, Bassotti G. Role of the Alteration in Calcium Homeostasis in Cell Death Induced by Clostridioides difficile Toxin A and Toxin B. BIOLOGY 2023; 12:1117. [PMID: 37627001 PMCID: PMC10452684 DOI: 10.3390/biology12081117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 08/05/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023]
Abstract
Clostridioides difficile (C. difficile), responsible for 15-25% of gastrointestinal infections, causes health problems mainly due to the toxic activity of toxins A and B (Tcds). These are responsible for its clinical manifestations, including diarrhea, pseudomembranous colitis, toxic megacolon and death, with a mortality of 5-30% in primary infection, that increase following relapses. Studies on Tcd-induced cell death have highlighted a key role of caspases, calpains, and cathepsins, with involvement of mitochondria and reactive oxygen species (ROS) in a complex signaling pathway network. The complex response in the execution of various types of cell death (apoptosis, necrosis, pyroptosis and pyknosis) depends on the amount of Tcd, cell types, and Tcd receptors involved, and could have as initial/precocious event the alterations in calcium homeostasis. The entities, peculiarities and cell types involved in these alterations will decide the signaling pathways activated and cell death type. Calcium homeostasis alterations can be caused by calcium influx through calcium channel activation, transient intracellular calcium oscillations, and leakage of calcium from intracellular stores. These increases in cytoplasmic calcium have important effects on all calcium-regulated molecules, which may play a direct role in several cell death types and/or activate other cell death effectors, such as caspases, calpains, ROS and proapoptotic Bcl-2 family members. Furthermore, some support for the possible role of the calcium homeostasis alteration in Tcd-induced cell death originates from the similarity with cytotoxic effects that cause pore-forming toxins, based mainly on calcium influx through plasma membrane pores.
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Affiliation(s)
- Katia Fettucciari
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy;
| | - Fabrizio Dini
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024 Matelica, Italy;
| | - Pierfrancesco Marconi
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy;
| | - Gabrio Bassotti
- Gastroenterology, Hepatology & Digestive Endoscopy Section, Department of Medicine and Surgery, University of Perugia, 06129 Perugia, Italy;
- Gastroenterology & Hepatology Unit, Santa Maria Della Misericordia Hospital, 06129 Perugia, Italy
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8
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Naz F, Petri WA. Host Immunity and Immunization Strategies for Clostridioides difficile Infection. Clin Microbiol Rev 2023; 36:e0015722. [PMID: 37162338 PMCID: PMC10283484 DOI: 10.1128/cmr.00157-22] [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] [Indexed: 05/11/2023] Open
Abstract
Clostridioides difficile infection (CDI) represents a significant challenge to public health. C. difficile-associated mortality and morbidity have led the U.S. CDC to designate it as an urgent threat. Moreover, recurrence or relapses can occur in up to a third of CDI patients, due in part to antibiotics being the primary treatment for CDI and the major cause of the disease. In this review, we summarize the current knowledge of innate immune responses, adaptive immune responses, and the link between innate and adaptive immune responses of the host against CDI. The other major determinants of CDI, such as C. difficile toxins, the host microbiota, and related treatments, are also described. Finally, we discuss the known therapeutic approaches and the current status of immunization strategies for CDI, which might help to bridge the knowledge gap in the generation of therapy against CDI.
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Affiliation(s)
- Farha Naz
- Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - William A. Petri
- Division of Infectious Diseases and International Health, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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9
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Campbell C, Kandalgaonkar MR, Golonka RM, Yeoh BS, Vijay-Kumar M, Saha P. Crosstalk between Gut Microbiota and Host Immunity: Impact on Inflammation and Immunotherapy. Biomedicines 2023; 11:294. [PMID: 36830830 PMCID: PMC9953403 DOI: 10.3390/biomedicines11020294] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 01/09/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
Gut microbes and their metabolites are actively involved in the development and regulation of host immunity, which can influence disease susceptibility. Herein, we review the most recent research advancements in the gut microbiota-immune axis. We discuss in detail how the gut microbiota is a tipping point for neonatal immune development as indicated by newly uncovered phenomenon, such as maternal imprinting, in utero intestinal metabolome, and weaning reaction. We describe how the gut microbiota shapes both innate and adaptive immunity with emphasis on the metabolites short-chain fatty acids and secondary bile acids. We also comprehensively delineate how disruption in the microbiota-immune axis results in immune-mediated diseases, such as gastrointestinal infections, inflammatory bowel diseases, cardiometabolic disorders (e.g., cardiovascular diseases, diabetes, and hypertension), autoimmunity (e.g., rheumatoid arthritis), hypersensitivity (e.g., asthma and allergies), psychological disorders (e.g., anxiety), and cancer (e.g., colorectal and hepatic). We further encompass the role of fecal microbiota transplantation, probiotics, prebiotics, and dietary polyphenols in reshaping the gut microbiota and their therapeutic potential. Continuing, we examine how the gut microbiota modulates immune therapies, including immune checkpoint inhibitors, JAK inhibitors, and anti-TNF therapies. We lastly mention the current challenges in metagenomics, germ-free models, and microbiota recapitulation to a achieve fundamental understanding for how gut microbiota regulates immunity. Altogether, this review proposes improving immunotherapy efficacy from the perspective of microbiome-targeted interventions.
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Affiliation(s)
- Connor Campbell
- Department of Physiology & Pharmacology, University of Toledo College of Medicine, Toledo, OH 43614, USA
| | - Mrunmayee R. Kandalgaonkar
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Rachel M. Golonka
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Beng San Yeoh
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Matam Vijay-Kumar
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Piu Saha
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
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10
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Nibbering B, Gerding DN, Kuijper EJ, Zwittink RD, Smits WK. Host Immune Responses to Clostridioides difficile: Toxins and Beyond. Front Microbiol 2022; 12:804949. [PMID: 34992590 PMCID: PMC8724541 DOI: 10.3389/fmicb.2021.804949] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 11/22/2021] [Indexed: 12/17/2022] Open
Abstract
Clostridioides difficile is often resistant to the actions of antibiotics to treat other bacterial infections and the resulting C. difficile infection (CDI) is among the leading causes of nosocomial infectious diarrhea worldwide. The primary virulence mechanism contributing to CDI is the production of toxins. Treatment failures and recurrence of CDI have urged the medical community to search for novel treatment options. Strains that do not produce toxins, so called non-toxigenic C. difficile, have been known to colonize the colon and protect the host against CDI. In this review, a comprehensive description and comparison of the immune responses to toxigenic C. difficile and non-toxigenic adherence, and colonization factors, here called non-toxin proteins, is provided. This revealed a number of similarities between the host immune responses to toxigenic C. difficile and non-toxin proteins, such as the influx of granulocytes and the type of T-cell response. Differences may reflect genuine variation between the responses to toxigenic or non-toxigenic C. difficile or gaps in the current knowledge with respect to the immune response toward non-toxigenic C. difficile. Toxin-based and non-toxin-based immunization studies have been evaluated to further explore the role of B cells and reveal that plasma cells are important in protection against CDI. Since the success of toxin-based interventions in humans to date is limited, it is vital that future research will focus on the immune responses to non-toxin proteins and in particular non-toxigenic strains.
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Affiliation(s)
- Britt Nibbering
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, Netherlands.,Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Dale N Gerding
- Department of Veterans Affairs, Research Service, Edward Hines Jr. VA Hospital, Hines, IL, United States
| | - Ed J Kuijper
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, Netherlands.,Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Romy D Zwittink
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, Netherlands.,Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Wiep Klaas Smits
- Center for Microbiome Analyses and Therapeutics, Leiden University Medical Center, Leiden, Netherlands.,Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
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11
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The Burkholderia cenocepacia Type VI Secretion System Effector TecA Is a Virulence Factor in Mouse Models of Lung Infection. mBio 2021; 12:e0209821. [PMID: 34579569 PMCID: PMC8546862 DOI: 10.1128/mbio.02098-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Burkholderia cenocepacia is a member of the Burkholderia cepacia complex (Bcc), a group of bacteria with members responsible for causing lung infections in cystic fibrosis (CF) patients. The most severe outcome of Bcc infection in CF patients is cepacia syndrome, a disease characterized by necrotizing pneumonia with bacteremia and sepsis. B. cenocepacia is strongly associated with cepacia syndrome, making it one of the most virulent members of the Bcc. Mechanisms underlying the pathogenesis of B. cenocepacia in lung infections and cepacia syndrome remain to be uncovered. B. cenocepacia is primarily an intracellular pathogen and encodes the type VI secretion system (T6SS) effector TecA, which is translocated into host phagocytes. TecA is a deamidase that inactivates multiple Rho GTPases, including RhoA. Inactivation of RhoA by TecA triggers assembly of the pyrin inflammasome, leading to secretion of proinflammatory cytokines, such as interleukin-1β, from macrophages. Previous work with the B. cenocepacia clinical isolate J2315 showed that TecA increases immunopathology during acute lung infection in C57BL/6 mice and suggested that this effector acts as a virulence factor by triggering assembly of the pyrin inflammasome. Here, we extend these results using a second B. cenocepacia clinical isolate, AU1054, to demonstrate that TecA exacerbates weight loss and lethality during lung infection in C57BL/6 mice and mice engineered to have a CF genotype. Unexpectedly, pyrin was dispensable for TecA virulence activity in both mouse infection models. Our findings establish that TecA is a B. cenocepacia virulence factor that exacerbates lung inflammation, weight loss, and lethality in mouse infection models.
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12
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MK2 degradation as a sensor of signal intensity that controls stress-induced cell fate. Proc Natl Acad Sci U S A 2021; 118:2024562118. [PMID: 34272277 DOI: 10.1073/pnas.2024562118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cell survival in response to stress is determined by the coordination of various signaling pathways. The kinase p38α is activated by many stresses, but the intensity and duration of the signal depends on the stimuli. How different p38α-activation dynamics may impact cell life/death decisions is unclear. Here, we show that the p38α-signaling output in response to stress is modulated by the expression levels of the downstream kinase MK2. We demonstrate that p38α forms a complex with MK2 in nonstimulated mammalian cells. Upon pathway activation, p38α phosphorylates MK2, the complex dissociates, and MK2 is degraded. Interestingly, transient p38α activation allows MK2 reexpression, reassembly of the p38α-MK2 complex, and cell survival. In contrast, sustained p38α activation induced by severe stress interferes with p38α-MK2 interaction, resulting in irreversible MK2 loss and cell death. MK2 degradation is mediated by the E3 ubiquitin ligase MDM2, and we identify four lysine residues in MK2 that are directly ubiquitinated by MDM2. Expression of an MK2 mutant that cannot be ubiquitinated by MDM2 enhances the survival of stressed cells. Our results indicate that MK2 reexpression and binding to p38α is critical for cell viability in response to stress and illustrate how particular p38α-activation patterns induced by different signals shape the stress-induced cell fate.
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13
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Kelly CP, Chen X, Williams D, Xu H, Cuddemi CA, Daugherty K, Barrett C, Miller M, Foussadier A, Lantz A, Banz A, Pollock NR. Host Immune Markers Distinguish Clostridioides difficile Infection From Asymptomatic Carriage and Non-C. difficile Diarrhea. Clin Infect Dis 2021; 70:1083-1093. [PMID: 31211839 DOI: 10.1093/cid/ciz330] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/22/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Recent data indicate that Clostridioides difficile toxin concentrations in stool do not differentiate between C. difficile infection (CDI) and asymptomatic carriage. Thus, we lack a method to distinguish a symptomatic patient with CDI from a colonized patient with diarrhea from another cause. To address this, we evaluated markers of innate and adaptive immunity in adult inpatients with CDI (diagnosed per US guidelines), asymptomatic carriage, or non-CDI diarrhea. METHODS CDI-NAAT patients had clinically significant diarrhea and positive nucleic acid amplification testing (NAAT) and received CDI treatment. Carrier-NAAT patients had positive stool NAAT but no diarrhea. NAAT-negative patients (with and without diarrhea) were also enrolled. A panel of cytokines and anti-toxin A and B immunoglobulin (Ig) were measured in serum; calprotectin and anti-toxin B Ig A/G were measured in stool. NAAT-positive stool samples were tested by an ultrasensitive toxin assay (clinical cutoff, 20 pg/mL). RESULTS Median values for interleukin (IL)-4, IL-6, IL-8, IL-10, IL-15, granulocyte colony-stimulating factor (GCSF), MCP-1, tumor necrosis factor α (TNF-α), and IgG anti-toxin A in blood and IgA/G anti-toxin B in stool were significantly higher in CDI patients compared with all other groups (P < .05). Concentration distributions for IL-6, GCSF, TNF-α, and IgG anti-toxin A in blood, as well as IgA and IgG anti-toxin B in stool, separated CDI patients from all other groups. CONCLUSIONS Specific markers of innate and adaptive immunity distinguish CDI from all other groups, suggesting potential clinical utility for identifying which NAAT- and toxin-positive patients with diarrhea truly have CDI.
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Affiliation(s)
- Ciaran P Kelly
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Massachusetts
| | - Xinhua Chen
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Massachusetts
| | - David Williams
- Institutional Centers for Clinical and Translational Research, Boston Children's Hospital, Massachusetts
| | - Hua Xu
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Massachusetts
| | - Christine A Cuddemi
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Massachusetts
| | - Kaitlyn Daugherty
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Massachusetts
| | - Caitlin Barrett
- Division of Gastroenterology, Department of Medicine, Beth Israel Deaconess Medical Center, Massachusetts
| | | | | | | | | | - Nira R Pollock
- Division of Infectious Disease, Department of Medicine, Beth Israel Deaconess Medical Center.,Department of Laboratory Medicine, Boston Children's Hospital, Massachusetts
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Chen X, Yang X, de Anda J, Huang J, Li D, Xu H, Shields KS, Džunková M, Hansen J, Patel IJ, Yee EU, Golenbock DT, Grant MA, Wong GCL, Kelly CP. Clostridioides difficile Toxin A Remodels Membranes and Mediates DNA Entry Into Cells to Activate Toll-Like Receptor 9 Signaling. Gastroenterology 2020; 159:2181-2192.e1. [PMID: 32841647 PMCID: PMC8720510 DOI: 10.1053/j.gastro.2020.08.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 07/31/2020] [Accepted: 08/18/2020] [Indexed: 01/05/2023]
Abstract
BACKGROUND & AIMS Clostridioides difficile toxin A (TcdA) activates the innate immune response. TcdA co-purifies with DNA. Toll-like receptor 9 (TLR9) recognizes bacterial DNA to initiate inflammation. We investigated whether DNA bound to TcdA activates an inflammatory response in murine models of C difficile infection via activation of TLR9. METHODS We performed studies with human colonocytes and monocytes and macrophages from wild-type and TLR9 knockout mice incubated with TcdA or its antagonist (ODN TTAGGG) or transduced with vectors encoding TLR9 or small-interfering RNAs. Cytokine production was measured with enzyme-linked immunosorbent assay. We studied a transduction domain of TcdA (TcdA57-80), which was predicted by machine learning to have cell-penetrating activity and confirmed by synchrotron small-angle X-ray scattering. Intestines of CD1 mice, C57BL6J mice, and mice that express a form of TLR9 that is not activated by CpG DNA were injected with TcdA, TLR9 antagonist, or both. Enterotoxicity was estimated based on loop weight to length ratios. A TLR9 antagonist was tested in mice infected with C difficile. We incubated human colon explants with an antagonist of TLR9 and measured TcdA-induced production of cytokines. RESULTS The TcdA57-80 protein transduction domain had membrane remodeling activity that allowed TcdA to enter endosomes. TcdA-bound DNA entered human colonocytes. TLR9 was required for production of cytokines by cultured cells and in human colon explants incubated with TcdA. TLR9 was required in TcdA-induced mice intestinal secretions and in the survival of mice infected by C difficile. Even in a protease-rich environment, in which only fragments of TcdA exist, the TcdA57-80 domain organized DNA into a geometrically ordered structure that activated TLR9. CONCLUSIONS TcdA from C difficile can bind and organize bacterial DNA to activate TLR9. TcdA and TcdA fragments remodel membranes, which allows them to access endosomes and present bacterial DNA to and activate TLR9. Rather than inactivating the ability of DNA to bind TLR9, TcdA appears to chaperone and organize DNA into an inflammatory, spatially periodic structure.
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Affiliation(s)
- Xinhua Chen
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
| | - Xiaotong Yang
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA,Institute of Microbiology and Immunology, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Jaime de Anda
- Department of Bioengineering, Department of Chemistry and Biochemistry, California Nano Systems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jun Huang
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA,Department of Colorectal Surgery, the 6th Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Dan Li
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Hua Xu
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Kelsey S. Shields
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Mária Džunková
- DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Joshua Hansen
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | - Eric U. Yee
- Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Douglas T. Golenbock
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Marianne A. Grant
- Division of Molecular and Vascular Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Gerard C. L. Wong
- Department of Bioengineering, Department of Chemistry and Biochemistry, California Nano Systems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA,Corresponding Authors: Xinhua Chen, PhD, , or Gerard C. L. Wong, PhD,
| | - Ciarán P. Kelly
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
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15
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Hernández Del Pino RE, Barbero AM, Español LÁ, Morro LS, Pasquinelli V. The adaptive immune response to Clostridioides difficile: A tricky balance between immunoprotection and immunopathogenesis. J Leukoc Biol 2020; 109:195-210. [PMID: 32829520 DOI: 10.1002/jlb.4vmr0720-201r] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/27/2020] [Accepted: 07/29/2020] [Indexed: 12/12/2022] Open
Abstract
Clostridioides difficile (C. difficile) is the major cause of hospital-acquired gastrointestinal infections in individuals following antibiotics treatment. The pathogenesis of C. difficile infection (CDI) is mediated mainly by the production of toxins that induce tissue damage and host inflammatory responses. While innate immunity is well characterized in human and animal models of CDI, adaptive immune responses remain poorly understood. In this review, the current understanding of adaptive immunity is summarized and its influence on pathogenesis and disease outcome is discussed. The perspectives on what we believe to be the main pending questions and the focus of future research are also provided. There is no doubt that the innate immune response provides a first line of defense to CDI. But, is the adaptive immune response a friend or a foe? Probably it depends on the course of the disease. Adaptive immunity is essential for pathogen eradication, but may also trigger uncontrolled or pathological inflammation. Most of the understanding of the role of T cells is based on findings from experimental models. While they are a very valuable tool for research studies, more studies in human are needed to translate these findings into human disease. Another main challenge is to unravel the role of the different T cell populations on protection or induction of immunopathogenesis.
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Affiliation(s)
- Rodrigo Emanuel Hernández Del Pino
- Centro de Investigaciones Básicas y Aplicadas (CIBA), Universidad Nacional del Noroeste de la Provincia de Buenos Aires (UNNOBA), Buenos Aires, Argentina.,Centro de Investigaciones y Transferencias del Noroeste de la Provincia de Buenos Aires (CIT NOBA), UNNOBA-Universidad Nacional de San Antonio de Areco (UNSAdA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Angela María Barbero
- Centro de Investigaciones Básicas y Aplicadas (CIBA), Universidad Nacional del Noroeste de la Provincia de Buenos Aires (UNNOBA), Buenos Aires, Argentina.,Centro de Investigaciones y Transferencias del Noroeste de la Provincia de Buenos Aires (CIT NOBA), UNNOBA-Universidad Nacional de San Antonio de Areco (UNSAdA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Laureano Ángel Español
- Centro de Investigaciones Básicas y Aplicadas (CIBA), Universidad Nacional del Noroeste de la Provincia de Buenos Aires (UNNOBA), Buenos Aires, Argentina
| | - Lorenzo Sebastián Morro
- Centro de Investigaciones Básicas y Aplicadas (CIBA), Universidad Nacional del Noroeste de la Provincia de Buenos Aires (UNNOBA), Buenos Aires, Argentina
| | - Virginia Pasquinelli
- Centro de Investigaciones Básicas y Aplicadas (CIBA), Universidad Nacional del Noroeste de la Provincia de Buenos Aires (UNNOBA), Buenos Aires, Argentina.,Centro de Investigaciones y Transferencias del Noroeste de la Provincia de Buenos Aires (CIT NOBA), UNNOBA-Universidad Nacional de San Antonio de Areco (UNSAdA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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16
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Amadou Amani S, Lang ML. Bacteria That Cause Enteric Diseases Stimulate Distinct Humoral Immune Responses. Front Immunol 2020; 11:565648. [PMID: 33042146 PMCID: PMC7524877 DOI: 10.3389/fimmu.2020.565648] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/18/2020] [Indexed: 12/12/2022] Open
Abstract
Bacterial enteric pathogens individually and collectively represent a serious global health burden. Humoral immune responses following natural or experimentally-induced infections are broadly appreciated to contribute to pathogen clearance and prevention of disease recurrence. Herein, we have compared observations on humoral immune mechanisms following infection with Citrobacter rodentium, the model for enteropathogenic Escherichia coli, Vibrio cholerae, Shigella species, Salmonella enterica species, and Clostridioides difficile. A comparison of what is known about the humoral immune responses to these pathogens reveals considerable variance in specific features of humoral immunity including establishment of high affinity, IgG class-switched memory B cell and long-lived plasma cell compartments. This article suggests that such variance could be contributory to persistent and recurrent disease.
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17
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Erickson SL, Alston L, Nieves K, Chang TKH, Mani S, Flannigan KL, Hirota SA. The xenobiotic sensing pregnane X receptor regulates tissue damage and inflammation triggered by C difficile toxins. FASEB J 2019; 34:2198-2212. [PMID: 31907988 PMCID: PMC7027580 DOI: 10.1096/fj.201902083rr] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 12/14/2022]
Abstract
Clostridioides difficile (formerly Clostridium difficile; C difficile), the leading cause of nosocomial antibiotic‐associated colitis and diarrhea in the industrialized world, triggers colonic disease through the release two toxins, toxin A (TcdA) and toxin B (TcdB), glucosyltransferases that modulate monomeric G‐protein function and alter cytoskeletal function. The initial degree of the host immune response to C difficile and its pathogenic toxins is a common indicator of disease severity and infection recurrence. Thus, targeting the intestinal inflammatory response during infection could significantly decrease disease morbidity and mortality. In the current study, we sought to interrogate the influence of the pregnane X receptor (PXR), a modulator of xenobiotic and detoxification responses, which can sense and respond to microbial metabolites and modulates inflammatory activity, during exposure to TcdA and TcdB. Following intrarectal exposure to TcdA/B, PXR‐deficient mice (Nr1i2−/−) exhibited reduced survival, an effect that was associated with increased levels of innate immune cell influx. This exacerbated response was associated with a twofold increase in the expression of Tlr4. Furthermore, while broad‐spectrum antibiotic treatment (to deplete the intestinal microbiota) did not alter the responses in Nr1i2−/− mice, blocking TLR4 signaling significantly reduced TcdA/B‐induced disease severity and immune responses in these mice. Lastly, to assess the therapeutic potential of targeting the PXR, we activated the PXR with pregnenolone 16α‐carbonitrile (PCN) in wild‐type mice, which greatly reduced the severity of TcdA/B‐induced damage and intestinal inflammation. Taken together, these data suggest that the PXR plays a role in the host's response to TcdA/B and may provide a novel target to dampen the inflammatory tissue damage in C difficile infections.
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Affiliation(s)
- Sarah L Erickson
- Department of Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Laurie Alston
- Department of Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Kristoff Nieves
- Department of Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Thomas K H Chang
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Sridhar Mani
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Kyle L Flannigan
- Department of Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada
| | - Simon A Hirota
- Department of Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
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18
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Wang C, Li Q, Ren J. Microbiota-Immune Interaction in the Pathogenesis of Gut-Derived Infection. Front Immunol 2019; 10:1873. [PMID: 31456801 PMCID: PMC6698791 DOI: 10.3389/fimmu.2019.01873] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 07/24/2019] [Indexed: 12/12/2022] Open
Abstract
Gut-derived infection is among the most common complications in patients who underwent severe trauma, serious burn, major surgery, hemorrhagic shock or severe acute pancreatitis (SAP). It could cause sepsis and multiple organ dysfunction syndrome (MODS), which are regarded as a leading cause of mortality in these cases. Gut-derived infection is commonly caused by pathological translocation of intestinal bacteria or endotoxins, resulting from the dysfunction of the gut barrier. In the last decades, the studies regarding to the pathogenesis of gut-derived infection mainly focused on the breakdown of intestinal epithelial tight junction and increased permeability. Limited information is available on the roles of intestinal microbial barrier in the development of gut-derived infection. Recently, advances of next-generation DNA sequencing techniques and its utilization has revolutionized the gut microecology, leading to novel views into the composition of the intestinal microbiota and its connections with multiple diseases. Here, we reviewed the recent progress in the research field of intestinal barrier disruption and gut-derived infection, mainly through the perspectives of the dysbiosis of intestinal microbiota and its interaction with intestinal mucosal immune cells. This review presents novel insights into how the gut microbiota collaborates with mucosal immune cells to involve the development of pathological bacterial translocation. The data might have important implication to better understand the mechanism underlying pathological bacterial translocation, contributing us to develop new strategies for prevention and treatment of gut-derived sepsis.
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Affiliation(s)
| | - Qiurong Li
- Research Institute of General Surgery, Jinling Hospital, Medical School, Nanjing University, Nanjing, China
| | - Jianan Ren
- Research Institute of General Surgery, Jinling Hospital, Medical School, Nanjing University, Nanjing, China
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19
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Clostridium difficile toxins induce VEGF-A and vascular permeability to promote disease pathogenesis. Nat Microbiol 2018; 4:269-279. [PMID: 30510170 DOI: 10.1038/s41564-018-0300-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 10/22/2018] [Indexed: 01/15/2023]
Abstract
Clostridium difficile infection (CDI) is mediated by two major exotoxins, toxin A (TcdA) and toxin B (TcdB), that damage the colonic epithelial barrier and induce inflammatory responses. The function of the colonic vascular barrier during CDI has been relatively understudied. Here we report increased colonic vascular permeability in CDI mice and elevated vascular endothelial growth factor A (VEGF-A), which was induced in vivo by infection with TcdA- and/or TcdB-producing C. difficile strains but not with a TcdA-TcdB- isogenic mutant. TcdA or TcdB also induced the expression of VEGF-A in human colonic mucosal biopsies. Hypoxia-inducible factor signalling appeared to mediate toxin-induced VEGF production in colonocytes, which can further stimulate human intestinal microvascular endothelial cells. Both neutralization of VEGF-A and inhibition of its signalling pathway attenuated CDI in vivo. Compared to healthy controls, CDI patients had significantly higher serum VEGF-A that subsequently decreased after treatment. Our findings indicate critical roles for toxin-induced VEGF-A and colonic vascular permeability in CDI pathogenesis and may also point to the pathophysiological significance of the gut vascular barrier in response to virulence factors of enteric pathogens. As an alternative to pathogen-targeted therapy, this study may enable new host-directed therapeutic approaches for severe, refractory CDI.
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20
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TPL2 Is a Key Regulator of Intestinal Inflammation in Clostridium difficile Infection. Infect Immun 2018; 86:IAI.00095-18. [PMID: 29844241 DOI: 10.1128/iai.00095-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/21/2018] [Indexed: 02/06/2023] Open
Abstract
Tumor progression locus 2 (TPL2), a serine/threonine protein kinase, is a major inflammatory mediator in immune cells. The predominant inflammatory actions of TPL2 depend on the activation of mitogen-activated protein kinases (MAPK) and the upregulated production of the cytokines tumor necrosis factor alpha (TNF-α) and interleukin 1β (IL-1β) in macrophages and dendritic cells in response to lipopolysaccharide (LPS). Significant increases in TNF-α, IL-6, IL-β, and IL-8 levels in patients with Clostridium difficile infection (CDI) have been reported. Both TNF-α and IL-6 have been postulated to play key roles in the systemic inflammatory response in CDI, and IL-8 is essential for the development of local intestinal inflammatory responses in CDI. The objective of this study was to elucidate the role of TPL2 in the pathogenesis of CDI. We found that TPL2 was significantly activated in human and mouse intestinal tissues upon C. difficile toxin exposure or CDI. We further demonstrated that TPL2 knockout (TPL2-KO) mice were significantly more resistant to CDI than wild-type mice, with significantly reduced production of TNF-α, IL-6, IL-1β, KC (a mouse homologue of IL-8), and myeloperoxidase (MPO) in the ceca and colons of TPL2-KO mice. Finally, we found that TPL2 inhibition by a specific inhibitor or TPL2 gene ablation significantly reduced TcdB-induced production of TNF-α, IL-6, IL-β, and KC by inhibiting the activation of p38, extracellular signal-regulated kinase (ERK), and c-Jun NH2-terminal kinase (JNK). Taken together, our data suggest that TPL2 represents a potential therapeutic target for CDI treatment.
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21
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Coffing H, Priyamvada S, Anbazhagan AN, Salibay C, Engevik M, Versalovic J, Yacyshyn MB, Yacyshyn B, Tyagi S, Saksena S, Gill RK, Alrefai WA, Dudeja PK. Clostridium difficile toxins A and B decrease intestinal SLC26A3 protein expression. Am J Physiol Gastrointest Liver Physiol 2018; 315:G43-G52. [PMID: 29597352 PMCID: PMC6109705 DOI: 10.1152/ajpgi.00307.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 03/06/2018] [Accepted: 03/12/2018] [Indexed: 01/31/2023]
Abstract
Clostridium difficile infection (CDI) is the primary cause of nosocomial diarrhea in the United States. Although C. difficile toxins A and B are the primary mediators of CDI, the overall pathophysiology underlying C. difficile-associated diarrhea remains poorly understood. Studies have shown that a decrease in both NHE3 (Na+/H+ exchanger) and DRA (downregulated in adenoma, Cl-/[Formula: see text] exchanger), resulting in decreased electrolyte absorption, is implicated in infectious and inflammatory diarrhea. Furthermore, studies have shown that NHE3 is depleted at the apical surface of intestinal epithelial cells and downregulated in patients with CDI, but the role of DRA in CDI remains unknown. In the current studies, we examined the effects of C. difficile toxins TcdA and TcdB on DRA protein and mRNA levels in intestinal epithelial cells (IECs). Our data demonstrated that DRA protein levels were significantly reduced in response to TcdA and TcdB in IECs in culture. This effect was also specific to DRA, as NHE3 and PAT-1 (putative anion transporter 1) protein levels were unaffected by TcdA and TcdB. Additionally, purified TcdA and TcdA + TcdB, but not TcdB, resulted in a decrease in colonic DRA protein levels in a toxigenic mouse model of CDI. Finally, patients with recurrent CDI also exhibited significantly reduced expression of colonic DRA protein. Together, these findings indicate that C. difficile toxins markedly downregulate intestinal expression of DRA which may contribute to the diarrheal phenotype of CDI. NEW & NOTEWORTHY Our studies demonstrate, for the first time, that C. difficile toxins reduce DRA protein, but not mRNA, levels in intestinal epithelial cells. These findings suggest that a downregulation of DRA may be a critical factor in C. difficile infection-associated diarrhea.
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Affiliation(s)
- Hayley Coffing
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Shubha Priyamvada
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Arivarasu N Anbazhagan
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Christine Salibay
- Department of Pathology, University of Illinois at Chicago , Chicago, Illinois
| | - Melinda Engevik
- Department of Pathology and Immunology, Baylor College of Medicine and Department of Pathology, Texas Children's Hospital , Houston, Texas
| | - James Versalovic
- Department of Pathology and Immunology, Baylor College of Medicine and Department of Pathology, Texas Children's Hospital , Houston, Texas
| | - Mary Beth Yacyshyn
- Division of Digestive Diseases, Department. of Medicine, University of Cincinnati College of Medicine , Cincinnati, Ohio
| | - Bruce Yacyshyn
- Division of Digestive Diseases, Department. of Medicine, University of Cincinnati College of Medicine , Cincinnati, Ohio
| | - Sangeeta Tyagi
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Seema Saksena
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - Ravinder K Gill
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Waddah A Alrefai
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
| | - Pradeep K Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago , Chicago, Illinois
- Jesse Brown Veterans Affairs Medical Center , Chicago, Illinois
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22
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Xiao P, Long X, Zhang L, Ye Y, Guo J, Liu P, Zhang R, Ning J, Yu W, Wei F, Yu J. Neurotensin/IL-8 pathway orchestrates local inflammatory response and tumor invasion by inducing M2 polarization of Tumor-Associated macrophages and epithelial-mesenchymal transition of hepatocellular carcinoma cells. Oncoimmunology 2018; 7:e1440166. [PMID: 29900041 DOI: 10.1080/2162402x.2018.1440166] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 01/31/2018] [Accepted: 02/06/2018] [Indexed: 12/12/2022] Open
Abstract
We previously demonstrated that neurotensin (NTS) induces local inflammation and promotes tumor invasion in hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms are not clear. In this study, positive correlations between NTS and interleukin (IL)-8 were identified at both the mRNA and protein levels in 71 fresh HCC tissues and 100 paraffin-embedded HCC tissues. Furthermore, significant correlations were determined among the co-expression of NTS and IL-8, infiltration of inflammatory cells and enhanced epithelial-mesenchymal transition (EMT) of HCC cells. NTS-induced IL-8 production was associated with activation of the mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) pathways rather than the protein kinase C (PKC) and phosphoinositide-3 kinase (PI3K) pathways, whose specific antagonists significantly inhibited activation of the NTS/IL-8 pathway. IL-8, which promoted EMT and HCC invasion both in vitro and in vivo, was produced by NTS-induced HCC cells and was effectively attenuated by blocking IL-8 receptors in vitro. Moreover, HCC-derived IL-8 attracted more CD68+ tumor-associated macrophages (TAMs) and CD66b+ polymorphonuclear neutrophils (PMNs) to the local microenvironment, displaying enhanced cytokine secretion and phagocytosis. IL-8 stimulated the M2 polarization of TAMs, which promoted the EMT and invasive potential of HCC cells. Blockage of the IL-8 receptor, NTR1 receptor or both significantly reduced HCC metastases in tumor-bearing mouse models via inhibiting EMT. In summary, aberrant activation of the NTS/IL-8 pathway in HCC dramatically stimulated the invasive potential of HCC cells. HCC-derived IL-8 promoted a pro-oncogenic inflammatory microenvironment by inducing M2-type TAMs and indirectly promoting EMT, which might be a valuable therapeutic target to prevent tumor progression.
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Affiliation(s)
- Pei Xiao
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy, Tianjin, P. R. China.,Department of Immunology, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P. R. China
| | - Xinxin Long
- Department of Oncology, Tengzhou Central People's Hospital, Tengzhou, Shandong, P.R. China
| | - Lijie Zhang
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy, Tianjin, P. R. China.,Department of Immunology, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P. R. China
| | - Yingnan Ye
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy, Tianjin, P. R. China
| | - Jincheng Guo
- Bioinformatics Research Group & Health Big-Data, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, P.R. China
| | - Pengpeng Liu
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy, Tianjin, P. R. China
| | - Rui Zhang
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy, Tianjin, P. R. China
| | - Junya Ning
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy, Tianjin, P. R. China.,Department of Immunology, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P. R. China
| | - Wenwen Yu
- Department of Immunology, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P. R. China
| | - Feng Wei
- Department of Immunology, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P. R. China
| | - Jinpu Yu
- Cancer Molecular Diagnostics Core, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy, Tianjin, P. R. China.,Department of Immunology, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, P. R. China
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Multitalented EspB of enteropathogenic Escherichia coli (EPEC) enters cells autonomously and induces programmed cell death in human monocytic THP-1 cells. Int J Med Microbiol 2018; 308:387-404. [PMID: 29550166 DOI: 10.1016/j.ijmm.2018.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/06/2018] [Accepted: 03/11/2018] [Indexed: 12/26/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) subvert host cell signaling pathways by injecting effector proteins via a Type 3 Secretion System (T3SS). The T3SS-dependent EspB protein is a multi-functional effector protein, which contributes to adherence and translocator pore formation and after injection exhibits several intracellular activities. In addition, EspB is also secreted into the environment. Effects of secreted EspB have not been reported thus far. As a surrogate for secreted EspB we employed recombinant EspB (rEspB) derived from the prototype EPEC strain E2348/69 and investigated the interactions of the purified protein with different human epithelial and immune cells including monocytic THP-1 cells, macrophages, dendritic cells, U-937, epithelial T84, Caco-2, and HeLa cells. To assess whether these proteins might exert a cytotoxic effect we monitored the release of lactate dehydrogenase (LDH) as well as propidium iodide (PI) uptake. For comparison, we also investigated several homologs of EspB such as IpaD of Shigella, and SipC, SipD, SseB, and SseD of Salmonella as purified recombinant proteins. Interestingly, cytotoxicity was only observed in THP-1 cells and macrophages, whereas epithelial cells remained unaffected. Cell fractionation and immune fluorescence experiments showed that rEspB enters cells autonomously, which suggests that EspB might qualify as a novel cell-penetrating effector protein (CPE). Using specific organelle tracers and inhibitors of signaling pathways we found that rEspB destroys the mitochondrial membrane potential - an indication of programmed cell death induction in THP-1 cells. Here we show that EspB not only constitutes an essential part of the T3SS-nanomachine and contributes to the arsenal of injected effector proteins but, furthermore, that secreted (recombinant) EspB autonomously enters host cells and selectively induces cell death in immune cells.
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Cellular Uptake and Mode-of-Action of Clostridium difficile Toxins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1050:77-96. [DOI: 10.1007/978-3-319-72799-8_6] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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25
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Huang GX, Qi MF, Li XL, Tang F, Zhu L. Involvement of upregulation of fibronectin in the pro‑adhesive and pro‑survival effects of glucocorticoid on melanoma cells. Mol Med Rep 2017; 17:3380-3387. [PMID: 29257300 DOI: 10.3892/mmr.2017.8269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 12/05/2017] [Indexed: 11/06/2022] Open
Abstract
Glucocorticoids (GCs) are important stress hormones, which are used as a concomitant medication during malignant tumor chemotherapy. Clinical and preclinical studies have linked GCs to melanoma growth and progression. However, the effects and mechanism of action of GCs on the adhesion and survival of melanoma cells are still unknown. In the present study the effect of dexamethasone (Dex), a synthetic GC, on fibronectin (FN) expression and its roles in regulating the adhesion and survival of melanoma cells were investigated. It was revealed that Dex significantly increased the levels of intracellular and secreted FN in melanoma cell lines by increasing glucocorticoid receptor‑mediated FN protein stability. Additionally, it was demonstrated that Dex (100 nM) significantly promoted the adhesion and survival of melanoma cells. Silencing FN expression abrogated the pro‑adhesive and pro‑survival effects of Dex in melanoma cells. Extracellular FN significantly enhanced melanoma cell adhesion and survival in the presence of cisplatin, whereas partially blocking extracellular FN signaling with a CD44 antibody significantly reduced FN‑enhanced adhesion and survival. This indicated that the upregulation of FN contributed to the pro‑survival effect of Dex by enhancing cell adhesion. It was also observed that activation of the PI3K/AKT signaling pathway by extracellular FN was involved in the FN‑mediated increase in melanoma cell survival. These findings increase understanding of the possible mechanisms by which GCs regulate melanoma cell adhesion and survival.
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Affiliation(s)
- Gao-Xiang Huang
- Department of Pathology, No. 181 Hospital of People's Liberation Army, Guilin, Guangxi 541002, P.R. China
| | - Min-Fang Qi
- Department of Pathology, No. 181 Hospital of People's Liberation Army, Guilin, Guangxi 541002, P.R. China
| | - Xiao-Long Li
- Department of Cardiology, Navy General Hospital, Beijing 100048, P.R. China
| | - Fang Tang
- Department of Pathology, No. 181 Hospital of People's Liberation Army, Guilin, Guangxi 541002, P.R. China
| | - Lei Zhu
- Department of Orthopedic Trauma Surgery, Changzheng Hospital, Second Military Medical University, Shanghai 200003, P.R. China
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26
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Chandrasekaran R, Lacy DB. The role of toxins in Clostridium difficile infection. FEMS Microbiol Rev 2017; 41:723-750. [PMID: 29048477 PMCID: PMC5812492 DOI: 10.1093/femsre/fux048] [Citation(s) in RCA: 210] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/10/2017] [Indexed: 02/06/2023] Open
Abstract
Clostridium difficile is a bacterial pathogen that is the leading cause of nosocomial antibiotic-associated diarrhea and pseudomembranous colitis worldwide. The incidence, severity, mortality and healthcare costs associated with C. difficile infection (CDI) are rising, making C. difficile a major threat to public health. Traditional treatments for CDI involve use of antibiotics such as metronidazole and vancomycin, but disease recurrence occurs in about 30% of patients, highlighting the need for new therapies. The pathogenesis of C. difficile is primarily mediated by the actions of two large clostridial glucosylating toxins, toxin A (TcdA) and toxin B (TcdB). Some strains produce a third toxin, the binary toxin C. difficile transferase, which can also contribute to C. difficile virulence and disease. These toxins act on the colonic epithelium and immune cells and induce a complex cascade of cellular events that result in fluid secretion, inflammation and tissue damage, which are the hallmark features of the disease. In this review, we summarize our current understanding of the structure and mechanism of action of the C. difficile toxins and their role in disease.
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Affiliation(s)
- Ramyavardhanee Chandrasekaran
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - D. Borden Lacy
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- The Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37232, USA
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27
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Abstract
Clostridium difficile is a leading cause of nosocomial infections, causing disease that ranges from mild diarrhea to potentially fatal colitis. A variety of surface proteins, including flagella, enable C. difficile colonization of the intestine. Once in the intestine, toxigenic C. difficile secretes two glucosylating toxins, TcdA and TcdB, which elicit inflammation and diarrheal disease symptoms. Regulation of colonization factors and TcdA and TcdB is an intense area of research in C. difficile biology. A recent publication from our group describes a novel regulatory mechanism that mediates the ON/OFF expression of co-regulated virulence factors of C. difficile, flagella and toxins. Herein, we review key findings from our work, present new data, and speculate the functional consequence of the ON/OFF expression of these virulence factors during host infection.
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Affiliation(s)
- Brandon R. Anjuwon-Foster
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Rita Tamayo
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA,CONTACT Rita Tamayo 125 Mason Farm Rd., CB #7290, Chapel Hill, NC, 27599
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Cytokines Are Markers of the Clostridium difficile-Induced Inflammatory Response and Predict Disease Severity. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2017; 24:CVI.00037-17. [PMID: 28592627 DOI: 10.1128/cvi.00037-17] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 05/24/2017] [Indexed: 12/25/2022]
Abstract
The host immune response affects pathogen virulence in Clostridium difficile infection (CDI). Thus, cytokine responses to CDI likely are associated with disease initiation and progression. Understanding the molecular drivers of inflammation and biochemical markers of disease severity is important for developing novel therapies and predicting disease prognosis. In this study, we investigated cytokine production in patients with CDI and evaluated the potential of cytokines to serve as biomarkers for CDI and predictors of disease severity. The systemic cytokine profiles of 36 CDI patients (20 with severe disease) and 8 healthy donors and the toxin-induced cytokine profiles of peripheral blood mononuclear cells (PBMC) were determined. Further, we evaluated glucosyltransferase (GT) activity in regulation of toxin-induced cytokine expression. We found upregulation of the majority of measured cytokines (11/20, 55%) in CDI patients. Interleukin-1β (IL-1β), IL-6, IL-8, IL-17A, and IL-16 were the most upregulated. High serum levels of IL-2 and IL-15 were associated with a poor prognosis in CDI patients, whereas high levels of IL-5 and gamma interferon (IFN-γ) were associated with less severe disease. Both TcdA and TcdB were potent inducers of cytokine responses, as demonstrated by stimulation of a greater number and amount of cytokines. In addition to confirming prior reports on the role of IL-8, IL-1β, and IL-6 in CDI, our data suggest that IL-16 and IL-17A, as well as the IL-1β/Th17 axis, play a key role in driving inflammatory responses in CDI. A functional GT domain of C. difficile toxins was required for the induction of a majority of cytokines investigated.
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29
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Péchiné S, Collignon A. Immune responses induced by Clostridium difficile. Anaerobe 2016; 41:68-78. [PMID: 27108093 DOI: 10.1016/j.anaerobe.2016.04.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 04/18/2016] [Accepted: 04/19/2016] [Indexed: 02/06/2023]
Abstract
The spectrum of Clostridium difficile infections is highly variable, ranging from asymptomatic carriage to fatal colitis depending on the strain virulence and on the host, its gut microbiota and its immune response. After disruption of the gut microbiota, C. difficile pathogenesis can be divided into three steps: 1) contamination by spores and their germination; 2) multiplication of vegetative cells and intestinal colonization using colonization factors; 3) production of the toxins TcdA and TcdB, and for some strains, the binary toxin, which are responsible for the clinical signs. Three lines of defense counteract C. difficile. The first line is the epithelial barrier, which is breached by the toxins. Then, a rapid innate immune response follows, which forms the second line of defense. It provides very quick defense reactions against C. difficile but is non-specific and does not confer memory. C. difficile and its virulence factors, the toxins and colonization factors, induce a highly pro-inflammatory response, which can be either beneficial or harmful, but triggers the adaptive immunity as the third line of defense required to control the infectious process. Adaptive immunity provides a highly specific immune response against C. difficile with memory and long lasting immunity. The innate and adaptive immune responses against the toxins and surface components are analyzed as well as their role in disease susceptibility, severity and recurrences.
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Affiliation(s)
- Séverine Péchiné
- Faculté de pharmacie, EA 4043 "Unité Bactéries Pathogènes et Santé", Univ. Paris-Sud, Université Paris-Saclay, 5 Rue Jean Baptiste Clément, 92296 Châtenay-Malabry Cedex, France
| | - Anne Collignon
- Faculté de pharmacie, EA 4043 "Unité Bactéries Pathogènes et Santé", Univ. Paris-Sud, Université Paris-Saclay, 5 Rue Jean Baptiste Clément, 92296 Châtenay-Malabry Cedex, France.
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30
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Abt MC, McKenney PT, Pamer EG. Clostridium difficile colitis: pathogenesis and host defence. Nat Rev Microbiol 2016; 14:609-20. [PMID: 27573580 DOI: 10.1038/nrmicro.2016.108] [Citation(s) in RCA: 336] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Clostridium difficile is a major cause of intestinal infection and diarrhoea in individuals following antibiotic treatment. Recent studies have begun to elucidate the mechanisms that induce spore formation and germination and have determined the roles of C. difficile toxins in disease pathogenesis. Exciting progress has also been made in defining the role of the microbiome, specific commensal bacterial species and host immunity in defence against infection with C. difficile. This Review will summarize the recent discoveries and developments in our understanding of C. difficile infection and pathogenesis.
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Affiliation(s)
- Michael C Abt
- Immunology Program, Lucille Castori Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA
| | - Peter T McKenney
- Immunology Program, Lucille Castori Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA
| | - Eric G Pamer
- Immunology Program, Lucille Castori Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, New York 10065, USA
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31
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High Mobility Group Box1 Protein Is Involved in Endoplasmic Reticulum Stress Induced by Clostridium difficile Toxin A. BIOMED RESEARCH INTERNATIONAL 2016; 2016:4130834. [PMID: 27579314 PMCID: PMC4992521 DOI: 10.1155/2016/4130834] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/05/2016] [Indexed: 11/17/2022]
Abstract
High Mobility Group Box1 (HMGB1), a damage-associated inflammatory factor, plays an important role in the pathogenesis of numerous chronic inflammatory and autoimmune diseases. In this study, the role of the HMGB1 in TcdA-induced ER stress was identified. Clostridium difficile toxin A is one of the major virulence factors of C. difficile infection (CDI) and has been proved to induce apoptotic cell death through ER stress. Our results showed that HMGB1 might play an important role in the TcdA-induced ER stress and unfolded protein response. HMGB1 activated molecular markers and induced the C/EBP homologous protein upregulation (CHOP). This study may provide the essential information for better understanding of the molecular mechanisms involved in CDI.
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32
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Yin L, Fang F, Song X, Wang Y, Huang G, Su J, Hui N, Lu J. The pro-adhesive and pro-survival effects of glucocorticoid in human ovarian cancer cells. J Mol Endocrinol 2016; 57:61-72. [PMID: 27151574 DOI: 10.1530/jme-15-0142] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 05/04/2016] [Indexed: 12/24/2022]
Abstract
Cell adhesion to extracellular matrix (ECM) is controlled by multiple signaling molecules and intracellular pathways, and is pivotal for survival and growth of cells from most solid tumors. Our previous works demonstrated that dexamethasone (DEX) significantly enhances cell adhesion and cell resistance to chemotherapeutics by increasing the levels of integrin β1, α4, and α5 in human ovarian cancer cells. However, it is unclear whether the components of ECM or other membrane molecules are also involved in the pro-adhesive effect of DEX in ovarian cancer cells. In this study, we demonstrated that the treatment of cells with DEX did not change the expression of collagens (I, III, and IV), laminin, CD44, and its principal ligand hyaluronan (HA), but significantly increased the levels of intracellular and secreted fibronectin (FN). Inhibiting the expression of FN with FN1 siRNA or blocking CD44, another FN receptor, with CD44 blocking antibody significantly attenuated the pro-adhesion of DEX, indicating that upregulation of FN mediates the pro-adhesive effect of DEX by its interaction with CD44 besides integrin β1. Moreover, DEX significantly enhanced cell resistance to the chemotherapeutic agent paclitaxel (PTX) by activating PI-3K-Akt pathway. Finally, we found that DEX also significantly upregulated the expression of MUC1, a transmembrane glycoprotein. Inhibiting the expression of MUC1 with MUC1 siRNA significantly attenuated the DEX-induced effects of pro-adhesion, Akt-activation, and pro-survival. In conclusion, these results provide new data that upregulation of FN and MUC1 by DEX contributes to DEX-induced pro-adhesion and protects ovarian cancer cells from chemotherapy.
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Affiliation(s)
- Lijuan Yin
- Department of PathophysiologyThe Second Military Medical University, Shanghai, China
| | - Fang Fang
- Department of Obstetrics and GynecologyChanghai Hospital, The Second Military Medical University, Shanghai, China
| | - Xinglei Song
- Department of PathophysiologyThe Second Military Medical University, Shanghai, China
| | - Yan Wang
- Department of PathophysiologyThe Second Military Medical University, Shanghai, China
| | - Gaoxiang Huang
- Department of PathophysiologyThe Second Military Medical University, Shanghai, China
| | - Jie Su
- Department of PathophysiologyThe Second Military Medical University, Shanghai, China
| | - Ning Hui
- Department of Obstetrics and GynecologyChanghai Hospital, The Second Military Medical University, Shanghai, China
| | - Jian Lu
- Department of PathophysiologyThe Second Military Medical University, Shanghai, China
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33
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Keel MK, Songer JG. The Distribution and Density of Clostridium difficile Toxin Receptors on the Intestinal Mucosa of Neonatal Pigs. Vet Pathol 2016; 44:814-22. [DOI: 10.1354/vp.44-6-814] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Clostridium difficile is an enteric pathogen affecting a variety of mammals, but it has only recently been diagnosed as a cause of neonatal typhlocolitis in pigs. The most important virulence factors of C. difficile are 2 large exotoxins, toxin A (TcdA) and toxin B (TcdB). TcdA is a potent enterotoxin with effects on host tissues that are dependent upon receptor-mediated endocytosis of the intact toxin. TcdB is an effective cytotoxin, but it apparently does not bind receptors on intact mucosal epithelium. TcdB is much less toxic in vivo unless there is underlying damage to the mucosa, and it is not essential for the virulence of C. difficile. One hypothesis to explain the resistance of most species as neonates (e.g., humans and hamsters) is that they may lack significant numbers of TcdA receptors. The susceptibility of neonatal pigs suggests cells of the gastrointestinal mucosa express sufficient numbers of toxin receptors for lesion development. Immunohistochemical (IHC) assays documented specific binding of TcdA, but not TcdB, to the epithelium of the small and large intestine. The carbohydrate Galα1–3/β1–4GlcNAc-R has been described as an important receptor for TcdA. However, IHC indicated a distribution on cell surfaces much different from that of TcdA binding, suggesting a specific interaction of toxin with an alternative receptor.
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Affiliation(s)
- M. K. Keel
- The University of Arizona, Department of Veterinary Sciences and Microbiology, Tucson, AZ
| | - J. G. Songer
- The University of Arizona, Department of Veterinary Sciences and Microbiology, Tucson, AZ
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34
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Di Bella S, Ascenzi P, Siarakas S, Petrosillo N, di Masi A. Clostridium difficile Toxins A and B: Insights into Pathogenic Properties and Extraintestinal Effects. Toxins (Basel) 2016; 8:E134. [PMID: 27153087 PMCID: PMC4885049 DOI: 10.3390/toxins8050134] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 02/06/2023] Open
Abstract
Clostridium difficile infection (CDI) has significant clinical impact especially on the elderly and/or immunocompromised patients. The pathogenicity of Clostridium difficile is mainly mediated by two exotoxins: toxin A (TcdA) and toxin B (TcdB). These toxins primarily disrupt the cytoskeletal structure and the tight junctions of target cells causing cell rounding and ultimately cell death. Detectable C. difficile toxemia is strongly associated with fulminant disease. However, besides the well-known intestinal damage, recent animal and in vitro studies have suggested a more far-reaching role for these toxins activity including cardiac, renal, and neurologic impairment. The creation of C. difficile strains with mutations in the genes encoding toxin A and B indicate that toxin B plays a major role in overall CDI pathogenesis. Novel insights, such as the role of a regulator protein (TcdE) on toxin production and binding interactions between albumin and C. difficile toxins, have recently been discovered and will be described. Our review focuses on the toxin-mediated pathogenic processes of CDI with an emphasis on recent studies.
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Affiliation(s)
- Stefano Di Bella
- 2nd Infectious Diseases Division, National Institute for Infectious Diseases "L. Spallanzani", Rome 00149, Italy.
| | - Paolo Ascenzi
- Department of Science, Roma Tre University, Rome 00154, Italy.
| | - Steven Siarakas
- Department of Microbiology and Infectious Diseases, Concord Repatriation General Hospital, Sydney 2139, Australia.
| | - Nicola Petrosillo
- 2nd Infectious Diseases Division, National Institute for Infectious Diseases "L. Spallanzani", Rome 00149, Italy.
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35
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Olabisi OA, Zhang JY, VerPlank L, Zahler N, DiBartolo S, Heneghan JF, Schlöndorff JS, Suh JH, Yan P, Alper SL, Friedman DJ, Pollak MR. APOL1 kidney disease risk variants cause cytotoxicity by depleting cellular potassium and inducing stress-activated protein kinases. Proc Natl Acad Sci U S A 2016; 113:830-7. [PMID: 26699492 PMCID: PMC4743809 DOI: 10.1073/pnas.1522913113] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Two specific genetic variants of the apolipoprotein L1 (APOL1) gene are responsible for the high rate of kidney disease in people of recent African ancestry. Expression in cultured cells of these APOL1 risk variants, commonly referred to as G1 and G2, results in significant cytotoxicity. The underlying mechanism of this cytotoxicity is poorly understood. We hypothesized that this cytotoxicity is mediated by APOL1 risk variant-induced dysregulation of intracellular signaling relevant for cell survival. To test this hypothesis, we conditionally expressed WT human APOL1 (G0), the APOL1 G1 variant, or the APOL1 G2 variant in human embryonic kidney cells (T-REx-293) using a tetracycline-mediated (Tet-On) system. We found that expression of either G1 or G2 APOL1 variants increased apparent cell swelling and cell death compared with G0-expressing cells. These manifestations of cytotoxicity were preceded by G1 or G2 APOL1-induced net efflux of intracellular potassium as measured by X-ray fluorescence, resulting in the activation of stress-activated protein kinases (SAPKs), p38 MAPK, and JNK. Prevention of net K(+) efflux inhibited activation of these SAPKs by APOL1 G1 or G2. Furthermore, inhibition of SAPK signaling and inhibition of net K(+) efflux abrogated cytotoxicity associated with expression of APOL1 risk variants. These findings in cell culture raise the possibility that nephrotoxicity of APOL1 risk variants may be mediated by APOL1 risk variant-induced net loss of intracellular K(+) and subsequent induction of stress-activated protein kinase pathways.
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Affiliation(s)
- Opeyemi A Olabisi
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114; Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; Harvard Medical School, Boston, MA 02215
| | - Jia-Yue Zhang
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; Harvard Medical School, Boston, MA 02215
| | | | | | - Salvatore DiBartolo
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - John F Heneghan
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; Harvard Medical School, Boston, MA 02215; Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Johannes S Schlöndorff
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; Harvard Medical School, Boston, MA 02215
| | - Jung Hee Suh
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; Harvard Medical School, Boston, MA 02215
| | - Paul Yan
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; Harvard Medical School, Boston, MA 02215
| | - Seth L Alper
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; Harvard Medical School, Boston, MA 02215; Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - David J Friedman
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; Harvard Medical School, Boston, MA 02215; Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA 02215
| | - Martin R Pollak
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215; Harvard Medical School, Boston, MA 02215;
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36
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Biomarkers of Gastrointestinal Host Responses to Microbial Infections. Mol Microbiol 2016. [DOI: 10.1128/9781555819071.ch46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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37
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Chen S, Sun C, Wang H, Wang J. The Role of Rho GTPases in Toxicity of Clostridium difficile Toxins. Toxins (Basel) 2015; 7:5254-67. [PMID: 26633511 PMCID: PMC4690124 DOI: 10.3390/toxins7124874] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/18/2015] [Accepted: 11/18/2015] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile (C. difficile) is the main cause of antibiotic-associated diarrhea prevailing in hospital settings. In the past decade, the morbidity and mortality of C. difficile infection (CDI) has increased significantly due to the emergence of hypervirulent strains. Toxin A (TcdA) and toxin B (TcdB), the two exotoxins of C. difficile, are the major virulence factors of CDI. The common mode of action of TcdA and TcdB is elicited by specific glucosylation of Rho-GTPase proteins in the host cytosol using UDP-glucose as a co-substrate, resulting in the inactivation of Rho proteins. Rho proteins are the key members in many biological processes and signaling pathways, inactivation of which leads to cytopathic and cytotoxic effects and immune responses of the host cells. It is supposed that Rho GTPases play an important role in the toxicity of C. difficile toxins. This review focuses on recent progresses in the understanding of functional consequences of Rho GTPases glucosylation induced by C. difficile toxins and the role of Rho GTPases in the toxicity of TcdA and TcdB.
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Affiliation(s)
- Shuyi Chen
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
| | - Chunli Sun
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
| | - Haiying Wang
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
| | - Jufang Wang
- School of Bioscience and Bioengineering, South China University of Technology (SCUT), Guangzhou 510006, China.
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38
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Jank T, Belyi Y, Aktories K. Bacterial glycosyltransferase toxins. Cell Microbiol 2015; 17:1752-65. [DOI: 10.1111/cmi.12533] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 12/28/2022]
Affiliation(s)
- Thomas Jank
- Institute for Experimental and Clinical Pharmacology and Toxicology; Albert-Ludwigs University of Freiburg; Freiburg Germany
| | - Yury Belyi
- Gamaleya Research Institute; Moscow 123098 Russia
- Freiburg Institute for Advanced Studies (FRIAS); Albert-Ludwigs University of Freiburg; Freiburg Germany
| | - Klaus Aktories
- Institute for Experimental and Clinical Pharmacology and Toxicology; Albert-Ludwigs University of Freiburg; Freiburg Germany
- Freiburg Institute for Advanced Studies (FRIAS); Albert-Ludwigs University of Freiburg; Freiburg Germany
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Shields K, Araujo-Castillo RV, Theethira TG, Alonso CD, Kelly CP. Recurrent Clostridium difficile infection: From colonization to cure. Anaerobe 2015; 34:59-73. [PMID: 25930686 PMCID: PMC4492812 DOI: 10.1016/j.anaerobe.2015.04.012] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 04/22/2015] [Accepted: 04/23/2015] [Indexed: 12/16/2022]
Abstract
Clostridium difficile infection (CDI) is increasingly prevalent, dangerous and challenging to prevent and manage. Despite intense national and international attention the incidence of primary and of recurrent CDI (PCDI and RCDI, respectively) have risen rapidly throughout the past decade. Of major concern is the increase in cases of RCDI resulting in substantial morbidity, morality and economic burden. RCDI management remains challenging as there is no uniformly effective therapy, no firm consensus on optimal treatment, and reliable data regarding RCDI-specific treatment options is scant. Novel therapeutic strategies are critically needed to rapidly, accurately, and effectively identify and treat patients with, or at-risk for, RCDI. In this review we consider the factors implicated in the epidemiology, pathogenesis and clinical presentation of RCDI, evaluate current management options for RCDI and explore novel and emerging therapies.
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Affiliation(s)
- Kelsey Shields
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA 02215, United States.
| | - Roger V Araujo-Castillo
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Lowry Medical Office Building, Suite GB 110 Francis Street, Boston, MA 02215, United States.
| | - Thimmaiah G Theethira
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA 02215, United States.
| | - Carolyn D Alonso
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Lowry Medical Office Building, Suite GB 110 Francis Street, Boston, MA 02215, United States.
| | - Ciaran P Kelly
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., Boston, MA 02215, United States.
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Abstract
Colonization with toxigenic Clostridium difficile may be associated with a wide spectrum of clinical presentation ranging from asymptomatic carriage to mild diarrhea to life-threatening colitis. Over the last 15 years, there has been a marked increase in the incidence of C. difficile infection, which predominantly affects elderly patients on antibiotics. More recently, there has been significant interest in the association between inflammatory bowel disease (IBD) and C. difficile infection. This review article discusses in some detail current knowledge of the mechanisms by which C. difficile toxins may mediate mucosal inflammation, together with the role of cell wall components of the microorganism in disease pathogenesis. Innate and adaptive host responses to C. difficile toxins and other components are described and include consideration of the potential role of known mucosal changes in IBD that may lead to an enhanced inflammatory response in the presence of C. difficile infection. Recent studies, which have characterized resident microbiota that may mediate protection against colonization by C. difficile, including their mechanisms of action, are also discussed. This includes the role of bile acids and 7α-dehydroxylase-expressing bacteria, such as Clostridium scindens. Recent studies suggest a higher carriage rate of C. difficile in patients with IBD. It is anticipated that future studies will determine the role of dysbiosis in IBD in predisposing to colonization with C. difficile.
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41
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Garmaroudi FS, Marchant D, Hendry R, Luo H, Yang D, Ye X, Shi J, McManus BM. Coxsackievirus B3 replication and pathogenesis. Future Microbiol 2015; 10:629-53. [DOI: 10.2217/fmb.15.5] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
ABSTRACT Viruses such as coxsackievirus B3 (CVB3) are entirely host cell-dependent parasites. Indeed, they must cleverly exploit various compartments of host cells to complete their life cycle, and consequently launch disease. Evolution has equipped this pico-rna-virus, CVB3, to use different strategies, including CVB3-induced direct damage to host cells followed by a host inflammatory response to CVB3 infection, and cell death to super-additively promote target organ tissue injury, and dysfunction. In this update, the patho-stratagems of CVB3 are explored from molecular, and systems-level approaches. In summarizing recent developments in this field, we focus particularly on mechanisms by which CVB3 can harness different host cell processes including kinases, host cell-killing and cell-eating machineries, matrix metalloproteinases and miRNAs to promote disease.
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Affiliation(s)
- Farshid S Garmaroudi
- UBC James Hogg Research Centre, Institute for Heart & Lung Health, St. Paul's Hospital, University of British Columbia, Vancouver, BC, V6Z, Canada
| | - David Marchant
- Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB, Canada
| | - Reid Hendry
- Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB, Canada
| | - Honglin Luo
- UBC James Hogg Research Centre, Institute for Heart & Lung Health, St. Paul's Hospital, University of British Columbia, Vancouver, BC, V6Z, Canada
| | - Decheng Yang
- UBC James Hogg Research Centre, Institute for Heart & Lung Health, St. Paul's Hospital, University of British Columbia, Vancouver, BC, V6Z, Canada
| | - Xin Ye
- UBC James Hogg Research Centre, Institute for Heart & Lung Health, St. Paul's Hospital, University of British Columbia, Vancouver, BC, V6Z, Canada
| | - Junyan Shi
- UBC James Hogg Research Centre, Institute for Heart & Lung Health, St. Paul's Hospital, University of British Columbia, Vancouver, BC, V6Z, Canada
| | - Bruce M McManus
- UBC James Hogg Research Centre, Institute for Heart & Lung Health, St. Paul's Hospital, University of British Columbia, Vancouver, BC, V6Z, Canada
- Centre of Excellence for Prevention of Organ Failure, Vancouver, BC, Canada
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42
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Sun X, Hirota SA. The roles of host and pathogen factors and the innate immune response in the pathogenesis of Clostridium difficile infection. Mol Immunol 2014; 63:193-202. [PMID: 25242213 DOI: 10.1016/j.molimm.2014.09.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/03/2014] [Accepted: 09/03/2014] [Indexed: 02/08/2023]
Abstract
Clostridium difficile (C. difficile) is the most common cause of nosocomial antibiotic-associated diarrhea and the etiologic agent of pseudomembranous colitis. The clinical manifestation of C. difficile infection (CDI) is highly variable, from asymptomatic carriage, to mild self-limiting diarrhea, to the more severe pseudomembranous colitis. Furthermore, in extreme cases, colonic inflammation and tissue damage can lead to toxic megacolon, a condition requiring surgical intervention. C. difficile expresses two key virulence factors; the exotoxins, toxin A (TcdA) and toxin B (TcdB), which are glucosyltransferases that target host-cell monomeric GTPases. In addition, some hypervirulent strains produce a third toxin, binary toxin or C. difficile transferase (CDT), which may contribute to the pathogenesis of CDI. More recently, other factors such as surface layer proteins (SLPs) and flagellin have also been linked to the inflammatory responses observed in CDI. Although the adaptive immune response can influence the severity of CDI, the innate immune responses to C. difficile and its toxins play crucial roles in CDI onset, progression, and overall prognosis. Despite this, the innate immune responses in CDI have drawn relatively little attention from clinical researchers. Targeting these responses may prove useful clinically as adjuvant therapies, especially in refractory and/or recurrent CDI. This review will focus on recent advances in our understanding of how C. difficile and its toxins modulate innate immune responses that contribute to CDI pathogenesis.
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Affiliation(s)
- Xingmin Sun
- Tufts University Cummings School of Veterinary Medicine, Department of Infectious Diseases and Global Health, North Grafton, MA 01536, USA; Tufts University, Clinical and Translational Science Institute, Boston, MA 02111, USA.
| | - Simon A Hirota
- University of Calgary, Snyder Institute for Chronic Diseases, Departments of Physiology & Pharmacology and Microbiology, Immunology & Infectious Diseases, Calgary, AB T2N4N1, Canada
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43
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Ye Y, Liu P, Wang Y, Li H, Wei F, Cheng Y, Han L, Yu J. Neurotensin, a Novel Messenger to Cross-Link Inflammation and Tumor Invasion via Epithelial-Mesenchymal Transition Pathway. Int Rev Immunol 2014; 35:340-350. [PMID: 25215420 DOI: 10.3109/08830185.2014.952412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Multiple cytokines and growth factors are critical for the prognosis of cancer which has been regarded as a worldwide health problem. Recently, neuropeptides, soluble factors regulating a series of functions in the central nervous system, have also been demonstrated to stimulate the proliferation and migration of tumor cells. Among these signaling peptides, the role of neurotensin (NTS) on malignancy procession has become a hot topic. The effects of NTS on tumor growth and its antiapoptosis role have already been identified. Subsequently, studies demonstrated the impact of NTS on the migration and invasion, but the molecular mechanisms involved are still unclear at present. Recently, some reports indicated that NTS could induce expression and secretion of interleukin-8 (IL-8) to promote local imflammatory response which might participate in epithelial-mesenchymal transition (EMT)-related tumor migration. In present review, we highlight the process of tumor EMT induced by NTS through stimulating IL-8 and the significance of NTS/IL-8 pathway in clinical application prospect.
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Affiliation(s)
- Yingnan Ye
- a Department of Immunology , Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy , Tianjin , P. R. China
| | - Pengpeng Liu
- b Cancer Molecular Diagnostic Center, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy , Tianjin , P. R. China
| | - Yue Wang
- a Department of Immunology , Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy , Tianjin , P. R. China
| | - Hui Li
- a Department of Immunology , Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy , Tianjin , P. R. China
| | - Feng Wei
- a Department of Immunology , Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy , Tianjin , P. R. China
| | - Yanan Cheng
- b Cancer Molecular Diagnostic Center, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy , Tianjin , P. R. China
| | - Lei Han
- b Cancer Molecular Diagnostic Center, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy , Tianjin , P. R. China
| | - Jinpu Yu
- a Department of Immunology , Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy , Tianjin , P. R. China.,b Cancer Molecular Diagnostic Center, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Prevention and Therapy , Tianjin , P. R. China.,c Biotherapy Center, Tianjin Medical University Cancer Institute & Hospital, National Clinical Research Center of Caner, Key Laboratory of Cancer Immunology and Biotherapy , Tianjin , P. R. China
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44
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Pawlowski SW. Clostridium difficile Infection Update for the Hospital-Based Physician. CURRENT EMERGENCY AND HOSPITAL MEDICINE REPORTS 2014. [DOI: 10.1007/s40138-014-0053-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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45
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Bibbò S, Lopetuso LR, Ianiro G, Di Rienzo T, Gasbarrini A, Cammarota G. Role of microbiota and innate immunity in recurrent Clostridium difficile infection. J Immunol Res 2014; 2014:462740. [PMID: 24995345 PMCID: PMC4068057 DOI: 10.1155/2014/462740] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 05/20/2014] [Indexed: 12/17/2022] Open
Abstract
Recurrent Clostridium difficile infection represents a burdensome clinical issue whose epidemiology is increasing worldwide. The pathogenesis is not yet completely known. Recent observations suggest that the alteration of the intestinal microbiota and impaired innate immunity may play a leading role in the development of recurrent infection. Various factors can cause dysbiosis. The causes most involved in the process are antibiotics, NSAIDs, acid suppressing therapies, and age. Gut microbiota impairment can favor Clostridium difficile infection through several mechanisms, such as the alteration of fermentative metabolism (especially SCFAs), the alteration of bile acid metabolism, and the imbalance of antimicrobial substances production. These factors alter the intestinal homeostasis promoting the development of an ecological niche for Clostridium difficile and of the modulation of immune response. Moreover, the intestinal dysbiosis can promote a proinflammatory environment, whereas Clostridium difficile itself modulates the innate immunity through both toxin-dependent and toxin-independent mechanisms. In this narrative review, we discuss how the intestinal microbiota modifications and the modulation of innate immune response can lead to and exacerbate Clostridium difficile infection.
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Affiliation(s)
- Stefano Bibbò
- A. Gemelli Hospital, Division of Internal Medicine and Gastroenterology, Department of Internal Medicine, School of Medicine and Surgery, Catholic University, 8, 00168 Rome, Italy
| | - Loris Riccardo Lopetuso
- A. Gemelli Hospital, Division of Internal Medicine and Gastroenterology, Department of Internal Medicine, School of Medicine and Surgery, Catholic University, 8, 00168 Rome, Italy
| | - Gianluca Ianiro
- A. Gemelli Hospital, Division of Internal Medicine and Gastroenterology, Department of Internal Medicine, School of Medicine and Surgery, Catholic University, 8, 00168 Rome, Italy
| | - Teresa Di Rienzo
- A. Gemelli Hospital, Division of Internal Medicine and Gastroenterology, Department of Internal Medicine, School of Medicine and Surgery, Catholic University, 8, 00168 Rome, Italy
| | - Antonio Gasbarrini
- A. Gemelli Hospital, Division of Internal Medicine and Gastroenterology, Department of Internal Medicine, School of Medicine and Surgery, Catholic University, 8, 00168 Rome, Italy
| | - Giovanni Cammarota
- A. Gemelli Hospital, Division of Internal Medicine and Gastroenterology, Department of Internal Medicine, School of Medicine and Surgery, Catholic University, 8, 00168 Rome, Italy
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46
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Fidaxomicin inhibits Clostridium difficile toxin A-mediated enteritis in the mouse ileum. Antimicrob Agents Chemother 2014; 58:4642-50. [PMID: 24890583 DOI: 10.1128/aac.02783-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Clostridium difficile infection (CDI) is a common, debilitating infection with high morbidity and mortality. C. difficile causes diarrhea and intestinal inflammation by releasing two toxins, toxin A and toxin B. The macrolide antibiotic fidaxomicin was recently shown to be effective in treating CDI, and its beneficial effect was associated with fewer recurrent infections in CDI patients. Since other macrolides possess anti-inflammatory properties, we examined the possibility that fidaxomicin alters C. difficile toxin A-induced ileal inflammation in mice. The ileal loops of anesthetized mice were injected with fidaxomicin (5, 10, or 20 μM), and after 30 min, the loops were injected with purified C. difficile toxin A or phosphate-buffered saline alone. Four hours after toxin A administration, ileal tissues were processed for histological evaluation (epithelial cell damage, neutrophil infiltration, congestion, and edema) and cytokine measurements. C. difficile toxin A caused histologic damage, evidenced by increased mean histologic score and ileal interleukin-1β (IL-1β) protein and mRNA expression. Treatment with fidaxomicin (20 μM) or its primary metabolite, OP-1118 (120 μM), significantly inhibited toxin A-mediated histologic damage and reduced the mean histology score and ileal IL-1β protein and mRNA expression. Both fidaxomicin and OP-1118 reduced toxin A-induced cell rounding in human colonic CCD-18Co fibroblasts. Treatment of ileal loops with vancomycin (20 μM) and metronidazole (20 μM) did not alter toxin A-induced histologic damage and IL-1β protein expression. In addition to its well known antibacterial effects against C. difficile, fidaxomicin may possess anti-inflammatory activity directed against the intestinal effects of C. difficile toxins.
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47
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Popoff MR. Bacterial factors exploit eukaryotic Rho GTPase signaling cascades to promote invasion and proliferation within their host. Small GTPases 2014; 5:28209. [PMID: 25203748 DOI: 10.4161/sgtp.28209] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Actin cytoskeleton is a main target of many bacterial pathogens. Among the multiple regulation steps of the actin cytoskeleton, bacterial factors interact preferentially with RhoGTPases. Pathogens secrete either toxins which diffuse in the surrounding environment, or directly inject virulence factors into target cells. Bacterial toxins, which interfere with RhoGTPases, and to some extent with RasGTPases, catalyze a covalent modification (ADPribosylation, glucosylation, deamidation, adenylation, proteolysis) blocking these molecules in their active or inactive state, resulting in alteration of epithelial and/or endothelial barriers, which contributes to dissemination of bacteria in the host. Injected bacterial virulence factors preferentially manipulate the RhoGTPase signaling cascade by mimicry of eukaryotic regulatory proteins leading to local actin cytoskeleton rearrangement, which mediates bacterial entry into host cells or in contrast escape to phagocytosis and immune defense. Invasive bacteria can also manipulate RhoGTPase signaling through recognition and stimulation of cell surface receptor(s). Changes in RhoGTPase activation state is sensed by the innate immunity pathways and allows the host cell to adapt an appropriate defense response.
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Affiliation(s)
- Michel R Popoff
- Unité des Bactéries anaérobies et Toxines; Institut Pasteur; Paris, France
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48
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The P2Y6 receptor mediates Clostridium difficile toxin-induced CXCL8/IL-8 production and intestinal epithelial barrier dysfunction. PLoS One 2013; 8:e81491. [PMID: 24278446 PMCID: PMC3838400 DOI: 10.1371/journal.pone.0081491] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 10/14/2013] [Indexed: 02/06/2023] Open
Abstract
C. difficile is a Gram-positive spore-forming anaerobic bacterium that is the leading cause of nosocomial diarrhea in the developed world. The pathogenesis of C. difficile infections (CDI) is driven by toxin A (TcdA) and toxin B (TcdB), secreted factors that trigger the release of inflammatory mediators and contribute to disruption of the intestinal epithelial barrier. Neutrophils play a key role in the inflammatory response and the induction of pseudomembranous colitis in CDI. TcdA and TcdB alter cytoskeletal signaling and trigger the release of CXCL8/IL-8, a potent neutrophil chemoattractant, from intestinal epithelial cells; however, little is known about the surface receptor(s) that mediate these events. In the current study, we sought to assess whether toxin-induced CXCL8/IL-8 release and barrier dysfunction are driven by the activation of the P2Y6 receptor following the release of UDP, a danger signal, from intoxicated Caco-2 cells. Caco-2 cells express a functional P2Y6 receptor and release measurable amounts of UDP upon exposure to TcdA/B. Toxin-induced CXCL8/IL-8 production and release were attenuated in the presence of a selective P2Y6 inhibitor (MRS2578). This was associated with inhibition of TcdA/B-induced activation of NFκB. Blockade of the P2Y6 receptor also attenuated toxin-induced barrier dysfunction in polarized Caco-2 cells. Lastly, pretreating mice with the P2Y6 receptor antagonists (MSR2578) attenuated TcdA/B-induced inflammation and intestinal permeability in an intrarectal toxin exposure model. Taken together these data outline a novel role for the P2Y6 receptor in the induction of CXCL8/IL-8 production and barrier dysfunction in response to C. difficile toxin exposure and may provide a new therapeutic target for the treatment of CDI.
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49
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Nookala AR, Shah A, Noel RJ, Kumar A. HIV-1 Tat-mediated induction of CCL5 in astrocytes involves NF-κB, AP-1, C/EBPα and C/EBPγ transcription factors and JAK, PI3K/Akt and p38 MAPK signaling pathways. PLoS One 2013; 8:e78855. [PMID: 24244375 PMCID: PMC3823997 DOI: 10.1371/journal.pone.0078855] [Citation(s) in RCA: 31] [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: 08/09/2013] [Accepted: 09/23/2013] [Indexed: 12/23/2022] Open
Abstract
The incidence of HIV-associated neurological disorders (HAND) has increased during recent years even though the highly active antiretroviral therapy (HAART) has significantly curtailed the virus replication and increased the life expectancy among HIV-1 infected individuals. These neurological deficits have been attributed to HIV proteins including HIV-1 Tat. HIV-1 Tat is known to up-regulate CCL5 expression in mouse astrocytes, but the mechanism of up-regulation is not known. The present study was undertaken with the objective of determining the mechanism(s) underlying HIV-1 Tat-mediated expression of CCL5 in astrocytes. SVGA astrocytes were transiently transfected with a plasmid encoding Tat, and expression of CCL5 was studied at the mRNA and protein levels using real time RT-PCR and multiplex cytokine bead array, respectively. HIV-1 Tat showed a time-dependent increase in the CCL5 expression with peak mRNA and protein levels, observed at 1 h and 48 h post-transfection, respectively. In order to explore the mechanism(s), pharmacological inhibitors and siRNA against different pathway(s) were used. Pre-treatment with SC514 (NF-κB inhibitor), LY294002 (PI3K inhibitor), AG490 (JAK2 inhibitor) and Janex-1 (JAK3 inhibitor) showed partial reduction of the Tat-mediated induction of CCL5 suggesting involvement of JAK, PI3K/Akt and NF-κB in CCL5 expression. These results were further confirmed by knockdown of the respective genes using siRNA. Furthermore, p38 MAPK was found to be involved since the knockdown of p38δ but not other isoforms showed partial reduction in CCL5 induction. This was further confirmed at transcriptional level that AP-1, C/EBPα and C/EBPγ were involved in CCL5 up-regulation.
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Affiliation(s)
- Anantha R. Nookala
- Division of Pharmacology and Toxicology, UMKC-School of Pharmacy, Kansas City, Missouri, United States of America
| | - Ankit Shah
- Division of Pharmacology and Toxicology, UMKC-School of Pharmacy, Kansas City, Missouri, United States of America
| | - Richard J. Noel
- Department of Biochemistry, Ponce School of Medicine and Health Sciences, Ponce, Puerto Rico, United States of America
| | - Anil Kumar
- Division of Pharmacology and Toxicology, UMKC-School of Pharmacy, Kansas City, Missouri, United States of America
- * E-mail:
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50
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In vivo physiological and transcriptional profiling reveals host responses to Clostridium difficile toxin A and toxin B. Infect Immun 2013; 81:3814-24. [PMID: 23897615 DOI: 10.1128/iai.00869-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Toxin A (TcdA) and toxin B (TcdB) of Clostridium difficile cause gross pathological changes (e.g., inflammation, secretion, and diarrhea) in the infected host, yet the molecular and cellular pathways leading to observed host responses are poorly understood. To address this gap, we evaluated the effects of single doses of TcdA and/or TcdB injected into the ceca of mice, and several endpoints were analyzed, including tissue pathology, neutrophil infiltration, epithelial-layer gene expression, chemokine levels, and blood cell counts, 2, 6, and 16 h after injection. In addition to confirming TcdA's gross pathological effects, we found that both TcdA and TcdB resulted in neutrophil infiltration. Bioinformatics analyses identified altered expression of genes associated with the metabolism of lipids, fatty acids, and detoxification; small GTPase activity; and immune function and inflammation. Further analysis revealed transient expression of several chemokines (e.g., Cxcl1 and Cxcl2). Antibody neutralization of CXCL1 and CXCL2 did not affect TcdA-induced local pathology or neutrophil infiltration, but it did decrease the peripheral blood neutrophil count. Additionally, low serum levels of CXCL1 and CXCL2 corresponded with greater survival. Although TcdA induced more pronounced transcriptional changes than TcdB and the upregulated chemokine expression was unique to TcdA, the overall transcriptional responses to TcdA and TcdB were strongly correlated, supporting differences primarily in timing and potency rather than differences in the type of intracellular host response. In addition, the transcriptional data revealed novel toxin effects (e.g., altered expression of GTPase-associated and metabolic genes) underlying observed physiological responses to C. difficile toxins.
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