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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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Costa DVS, Shin JH, Goldbeck SM, Bolick DT, Mesquita FS, Loureiro AV, Rodrigues-Jesus MJ, Brito GAC, Warren CA. Adenosine receptors differentially mediate enteric glial cell death induced by Clostridioides difficile Toxins A and B. Front Immunol 2023; 13:956326. [PMID: 36726986 PMCID: PMC9885079 DOI: 10.3389/fimmu.2022.956326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 12/21/2022] [Indexed: 01/18/2023] Open
Abstract
Increased risk of intestinal dysfunction has been reported in patients after Clostridioides difficile infection (CDI). Enteric glial cells (EGCs), a component of the enteric nervous system (ENS), contribute to gut homeostasis. Previous studies showed that adenosine receptors, A2A and A2B, modulate inflammation during CDI. However, it is unknown how these receptors can modulate the EGC response to the C. difficile toxins (TcdA and TcdB). We investigated the effects of these toxins on the expression of adenosine receptors in EGCs and the role of these receptors on toxin-induced EGC death. Rat EGCs line were incubated with TcdA or TcdB alone or in combination with adenosine analogues 1h prior to toxins challenge. After incubation, EGCs were collected to evaluate gene expression (adenosine receptors and proinflammatory markers) and cell death. In vivo, WT, A2A, and A2B KO mice were infected with C. difficile, euthanized on day 3 post-infection, and cecum tissue was processed. TcdA and TcdB increased A2A and A3 transcripts, as well as decreased A2B. A2A agonist, but not A2A antagonist, decreased apoptosis induced by TcdA and TcdB in EGCs. A2B blocker, but not A2B agonist, diminished apoptosis in EGCs challenged with both toxins. A3 agonist, but not A3 blocker, reduced apoptosis in EGCs challenged with TcdA and TcdB. Inhibition of protein kinase A (PKA) and CREB, both involved in the main signaling pathway driven by activation of adenosine receptors, decreased EGC apoptosis induced by both toxins. A2A agonist and A2B antagonist decreased S100B upregulation induced by C. difficile toxins in EGCs. In vivo, infected A2B KO mice, but not A2A, exhibited a decrease in cell death, including EGCs and enteric neuron loss, compared to infected WT mice, reduced intestinal damage and decreased IL-6 and S100B levels in cecum. Our findings indicate that upregulation of A2A and A3 and downregulation of A2B in EGCs and downregulation of A2B in intestinal tissues elicit a protective response against C. difficile toxins. Adenosine receptors appear to play a regulatory role in EGCs death and proinflammatory response induced by TcdA and TcdB, and thus may be potential targets of intervention to prevent post-CDI intestinal dysmotility.
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Affiliation(s)
- Deiziane V S Costa
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, United States
| | - Jae H Shin
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, United States
| | - Sophia M Goldbeck
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, United States
| | - David T Bolick
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, United States
| | - Flavio S Mesquita
- Department of Microbiology, University of Sao Paulo, Sao Paulo, Brazil
| | - Andrea V Loureiro
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Mônica J Rodrigues-Jesus
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, United States
| | - Gerly A C Brito
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - Cirle A Warren
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, United States
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Chu KO, Chan KP, Yip YWY, Chu WK, Wang C, Pang CP. Systemic and Ocular Anti-Inflammatory Mechanisms of Green Tea Extract on Endotoxin-Induced Ocular Inflammation. Front Endocrinol (Lausanne) 2022; 13:899271. [PMID: 35909558 PMCID: PMC9335207 DOI: 10.3389/fendo.2022.899271] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/22/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction Green tea extract (GTE) alleviated ocular inflammations in endotoxin-induced uveitis (EIU) rat model induced by lipopolysaccharide (LPS) but the underlying mechanism is unclear. Objectives To investigate the systematic and local mechanisms of the alleviation by untargeted metabolomics using liquid chromatography-tandem mass spectrometry. Methods Sprague-Dawley rats were divided into control group, LPS treatment group, and LPS treatment group treated with GTE two hours after LPS injection. The eyes were monitored by slip lamp and electroretinography examination after 24 hours. The plasma and retina were collected for metabolomics analysis. Results In LPS treated rats, the iris showed hyperemia. Plasma prostaglandins, arachidonic acids, corticosteroid metabolites, and bile acid metabolites increased. In the retina, histamine antagonists, corticosteroids, membrane phospholipids, free antioxidants, and sugars also increased but fatty acid metabolites, N-acetylglucosamine-6-sulphate, pyrocatechol, and adipic acid decreased. After GTE treatment, the a- and b- waves of electroretinography increased by 13%. Plasma phosphorylcholine lipids increased but plasma prostaglandin E1, cholanic metabolites, and glutarylglycine decreased. In the retina, tetranor-PGAM, pantothenic derivatives, 2-ethylacylcarinitine, and kynuramine levels decreased but anti-oxidative seleno-peptide level increased. Only phospholipids, fatty acids, and arachidonic acid metabolites in plasma and in the retina had significant correlation (p < 0.05, r > 0.4 or r < -0.4). Conclusions The results showed GTE indirectly induced systemic phosphorylcholine lipids to suppress inflammatory responses, hepatic damage, and respiratory mitochondrial stress in EIU rats induced by LPS. Phospholipids may be a therapeutic target of GTE for anterior chamber inflammation.
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Affiliation(s)
- Kai On Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Kwok Ping Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Yolanda Wong Ying Yip
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Wai Kit Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Chi Chiu Wang
- Department of Obstetrics and Gynaecology, the Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Li Ka Shing Institute of Health Science, the Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
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Loureiro AV, Barbosa MLL, Morais MLGS, Souza IP, Terceiro LS, Martins CS, Sousa APR, Leitão RFC, Shin JH, Warren CA, Costa DVS, Brito GAC. Host and Clostridioides difficile-Response Modulated by Micronutrients and Glutamine: An Overview. Front Nutr 2022; 9:849301. [PMID: 35795588 PMCID: PMC9251358 DOI: 10.3389/fnut.2022.849301] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 05/16/2022] [Indexed: 11/17/2022] Open
Abstract
Changes in intestinal microbiota are integral to development of Clostridioides difficile (C. difficile)—associated nosocomial diarrhea. Certain diets, especially Western diets, increase susceptibility to C. difficile infection (CDI). Here, we discuss recent findings regarding how nutrients modulate response of the host and C. difficile during infection. Calcium has a role in the sporulation and germination process. Selenium is effective in reducing the total amount of C. difficile toxin A (TcdA) and toxin B (TcdB) and in decreasing its cytotoxicity. In addition, selenium phosphate synthetase deficiency reduces C. difficile growth and spore production. On the other hand, iron has a dual role in C. difficile growth. For instance, high intracellular levels can generate reactive hydroxyl radicals, whereas low levels can reduce its growth. In humans, zinc deficiency appears to be related to the recurrence of CDI, in contrast, in the CDI model in mice a diet rich in zinc increased the toxin's activity. Low vitamin D levels contribute to C. difficile colonization, toxin production, and inflammation. Furthermore, glutamine appears to protect intestinal epithelial cells from the deleterious effects of TcdA and TcdB. In conclusion, nutrients play an important role in modulating host and pathogen response. However, further studies are needed to better understand the mechanisms and address some controversies.
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Affiliation(s)
- Andréa V. Loureiro
- Department of Medical Sciences, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Maria L. L. Barbosa
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Maria L. G. S. Morais
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Ismael P. Souza
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Letícia S. Terceiro
- Department of Medical Sciences, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Conceição S. Martins
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Arkila P. R. Sousa
- Department of Pharmacology and Physiology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Renata F. C. Leitão
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Jae H. Shin
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, VA, United States
| | - Cirle A. Warren
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, VA, United States
| | - Deiziane V. S. Costa
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, VA, United States
| | - Gerly A. C. Brito
- Department of Medical Sciences, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
- Department of Pharmacology and Physiology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
- *Correspondence: Gerly A. C. Brito
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Sun L, Li X, Guan H, Chen S, Fan X, Zhou C, Yang H, Xiao W. A Novel Role of A 2AR in the Maintenance of Intestinal Barrier Function of Enteric Glia from Hypoxia-Induced Injury by Combining with mGluR5. Front Pharmacol 2021; 12:633403. [PMID: 34093180 PMCID: PMC8173626 DOI: 10.3389/fphar.2021.633403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/25/2021] [Indexed: 12/20/2022] Open
Abstract
During acute intestinal ischemia reperfusion (IR) injury, the intestinal epithelial barrier (IEB) function is often disrupted. Enteric glial cells (EGCs) play an important role in maintaining the integrity of IEB functions. However, how EGCs regulate IEB function under IR stimulation is unknown. The present study reveals that the adenosine A2A receptor (A2AR) is important for mediating the barrier-modulating roles of EGCs. A2AR knockout (KO) experiments revealed more serious intestinal injury in A2AR KO mice than in WT mice after IR stimulation. Moreover, A2AR expression was significantly increased in WT mice when challenged by IR. To further investigate the role of A2AR in IEB, we established an in vitro EGC-Caco-2 co-culture system. Hypoxia stimulation was used to mimic the process of in vivo IR. Treating EGCs with the CGS21680 A2AR agonist attenuated hypoxia-induced intestinal epithelium damage through up-regulating ZO-1 and occludin expression in cocultured Caco-2 monolayers. Furthermore, we showed that A2AR and metabotropic glutamate receptor 5 (mGluR5) combine to activate the PKCα-dependent pathway in conditions of hypoxia. This study shows, for the first time, that hypoxia induces A2AR-mGluR5 interaction in EGCs to protect IEB function via the PKCα pathway.
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Affiliation(s)
- Lihua Sun
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Xiang Li
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Haidi Guan
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Shuaishuai Chen
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Xin Fan
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Chao Zhou
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Hua Yang
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Weidong Xiao
- Department of General Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
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Kullar R, Tran MCN, Goldstein EJC. Investigational Treatment Agents for Recurrent Clostridioides difficile Infection (rCDI). J Exp Pharmacol 2020; 12:371-384. [PMID: 33116952 PMCID: PMC7553590 DOI: 10.2147/jep.s242959] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/13/2020] [Indexed: 11/23/2022] Open
Abstract
Clostridioides difficile infection (CDI) is a major cause of nosocomial diarrhea that is deemed a global health threat. C. difficile strain BI/NAP1/027 has contributed to the increase in the mortality, severity of CDI outbreaks and recurrence rates (rCDI). Updated CDI treatment guidelines suggest vancomycin and fidaxomicin as initial first-line therapies that have initial clinical cure rates of over 80%. Unacceptably high recurrence rates of 15–30% in patients for the first episode and 40% for the second recurrent episode are reported. Alternative treatments for rCDI include fecal microbiota transplant and a human monoclonal antibody, bezlotoxumab, that can be used in patients with high risk of rCDI. Various emerging potential therapies with narrow spectrum of activity and little systemic absorption that are in development include 1) Ibezapolstat (formerly ACX-362E), MGB-BP-3, and DS-2969b-targeting bacterial DNA replication, 2) CRS3213 (REP3123)-inhibiting toxin production and spore formation, 3) ramizol and ramoplanin-affecting bacterial cell wall, 4) LFF-571-blocking protein synthesis, 5) Alanyl-L-Glutamine (alanylglutamine)-inhibiting damage caused by C. difficile by protecting intestinal mucosa, and 6) DNV3837 (MCB3681)-prodrug consisting of an oxazolidinone–quinolone combination that converts to the active form DNV3681 that has activity in vitro against C. difficile. This review article provides an overview of these developing drugs that can have potential role in the treatment of rCDI and in lowering recurrence rates.
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Affiliation(s)
| | - Mai-Chi N Tran
- Pharmacy Department, Keck Medical Center of USC, Los Angeles, CA, USA.,Clinica Juan Pablo Medical Group, Los Angeles, CA, USA
| | - Ellie J C Goldstein
- R.M. Alden Research Laboratory, Santa Monica, CA, USA.,David Geffen School of Medicine, Los Angeles, CA, USA
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Sullivan JA, AlAdra DP, Olson BM, McNeel DG, Burlingham WJ. Infectious Tolerance as Seen With 2020 Vision: The Role of IL-35 and Extracellular Vesicles. Front Immunol 2020; 11:1867. [PMID: 32983104 PMCID: PMC7480133 DOI: 10.3389/fimmu.2020.01867] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/13/2020] [Indexed: 12/26/2022] Open
Abstract
Originally identified as lymphocyte regulation of fellow lymphocytes, our understanding of infectious tolerance has undergone significant evolutions in understanding since being proposed in the early 1970s by Gershon and Kondo and expanded upon by Herman Waldman two decades later. The evolution of our understanding of infectious tolerance has coincided with significant cellular and humoral discoveries. The early studies leading to the isolation and identification of Regulatory T cells (Tregs) and cytokines including TGFβ and IL-10 in the control of peripheral tolerance was a paradigm shift in our understanding of infectious tolerance. More recently, another potential, paradigm shift in our understanding of the "infectious" aspect of infectious tolerance was proposed, identifying extracellular vesicles (EVs) as a mechanism for propagating infectious tolerance. In this review, we will outline the history of infectious tolerance, focusing on a potential EV mechanism for infectious tolerance and a novel, EV-associated form for the cytokine IL-35, ideally suited to the task of propagating tolerance by "infecting" other lymphocytes.
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Affiliation(s)
- Jeremy A Sullivan
- Department of Surgery-Transplant Division, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - David P AlAdra
- Department of Surgery-Transplant Division, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Brian M Olson
- Departments of Hematology and Medical Oncology, Urology, and Surgery, Emory University School of Medicine, Atlanta, GA, United States
| | - Douglas G McNeel
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - William J Burlingham
- Department of Surgery-Transplant Division, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
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8
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Bartelt LA, Bolick DT, Guerrant RL. Disentangling Microbial Mediators of Malnutrition: Modeling Environmental Enteric Dysfunction. Cell Mol Gastroenterol Hepatol 2019; 7:692-707. [PMID: 30630118 PMCID: PMC6477186 DOI: 10.1016/j.jcmgh.2018.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 12/12/2022]
Abstract
Environmental enteric dysfunction (EED) (also referred to as environmental enteropathy) is a subclinical chronic intestinal disorder that is an emerging contributor to early childhood malnutrition. EED is common in resource-limited settings, and is postulated to consist of small intestinal injury, dysfunctional nutrient absorption, and chronic inflammation that results in impaired early child growth attainment. Although there is emerging interest in the hypothetical potential for chemical toxins in the environmental exposome to contribute to EED, the propensity of published data, and hence the focus of this review, implicates a critical role of environmental microbes. Early childhood malnutrition and EED are most prevalent in resource-limited settings where food is limited, and inadequate access to clean water and sanitation results in frequent gastrointestinal pathogen exposures. Even as overt diarrhea rates in these settings decline, silent enteric infections and faltering growth persist. Furthermore, beyond restricted physical growth, EED and/or enteric pathogens also associate with impaired oral vaccine responses, impaired cognitive development, and may even accelerate metabolic syndrome and its cardiovascular consequences. As these potentially costly long-term consequences of early childhood enteric infections increasingly are appreciated, novel therapeutic strategies that reverse damage resulting from nutritional deficiencies and microbial insults in the developing small intestine are needed. Given the inherent limitations in investigating how specific intestinal pathogens directly injure the small intestine in children, animal models provide an affordable and controlled opportunity to elucidate causal sequelae of specific enteric infections, to differentiate consequences of defined nutrient deprivation alone from co-incident enteropathogen insults, and to correlate the resulting gut pathologies with their functional impact during vulnerable early life windows.
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Affiliation(s)
- Luther A Bartelt
- Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Center for Gastrointestinal Biology and Disease, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
| | - David T Bolick
- Center for Global Health, Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
| | - Richard L Guerrant
- Center for Global Health, Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, Virginia
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9
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Dieterle MG, Rao K, Young VB. Novel therapies and preventative strategies for primary and recurrent Clostridium difficile infections. Ann N Y Acad Sci 2019; 1435:110-138. [PMID: 30238983 PMCID: PMC6312459 DOI: 10.1111/nyas.13958] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/16/2018] [Accepted: 08/03/2018] [Indexed: 12/15/2022]
Abstract
Clostridium difficile is the leading infectious cause of antibiotic-associated diarrhea and colitis. C. difficile infection (CDI) places a heavy burden on the healthcare system, with nearly half a million infections yearly and an approximate 20% recurrence risk after successful initial therapy. The high incidence has driven new research on improved prevention such as the emerging use of probiotics, intestinal microbiome manipulation during antibiotic therapies, vaccinations, and newer antibiotics that reduce the disruption of the intestinal microbiome. While the treatment of acute C. difficile is effective in most patients, it can be further optimized by adjuvant therapies that improve the initial treatment success and decrease the risk of subsequent recurrence. Finally, the high risk of recurrence has led to multiple emerging therapies that target toxin activity, recovery of the intestinal microbial community, and elimination of latent C. difficile in the intestine. In summary, CDIs illustrate the complex interaction among host physiology, microbial community, and pathogen that requires specific therapies to address each of the factors leading to primary infection and recurrence.
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Affiliation(s)
- Michael G. Dieterle
- University of Michigan Medical School, Medical Scientist Training Program (MSTP), Ann Arbor, Michigan
- University of Michigan Department of Microbiology and Immunology, Ann Arbor, Michigan
| | - Krishna Rao
- University of Michigan Department of Internal Medicine, Infectious Diseases Division, Ann Arbor, Michigan
| | - Vincent B. Young
- University of Michigan Department of Microbiology and Immunology, Ann Arbor, Michigan
- University of Michigan Department of Internal Medicine, Infectious Diseases Division, Ann Arbor, Michigan
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10
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Antonioli L, El-Tayeb A, Pellegrini C, Fornai M, Awwad O, Giustarini G, Natale G, Ryskalin L, Németh ZH, Müller CE, Blandizzi C, Colucci R. Anti-inflammatory effect of a novel locally acting A 2A receptor agonist in a rat model of oxazolone-induced colitis. Purinergic Signal 2017; 14:27-36. [PMID: 29116551 DOI: 10.1007/s11302-017-9591-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/23/2017] [Indexed: 10/18/2022] Open
Abstract
Adenosine represents a powerful modulating factor, which has been shown to orchestrate the scope, duration, and remission of the inflammatory response through the activation of four specific receptors, classified as A1, A2A, A2B, and A3, all being widely expressed in a variety of immune cells. Several selective A2A receptor agonists have displayed anti-inflammatory effects, through the suppression of IL-12, TNF, and IFN-γ production by monocytes and lymphocytes, in the setting of chronic intestinal inflammation. However, the therapeutic application of A2A receptor agonists remains hindered by the risk of serious cardiovascular adverse effects arising from the wide systemic distribution of A2A receptors. The present study focused on evaluating the anti-inflammatory effects of the novel poorly absorbed A2A receptor agonist PSB-0777 in a rat model of oxazolone-induced colitis as well as to evaluate its cardiovascular adverse effects, paying particular attention to the onset of hypotension, one of the main adverse effects associated with the systemic pharmacological activation of A2A receptors. Colitis was associated with decreased body weight, an enhanced microscopic damage score and increased levels of colonic myeloperoxidase (MPO). PSB-0777, but not dexamethasone, improved body weight. PSB-0777 and dexamethasone ameliorated microscopic indexes of inflammation and reduced MPO levels. The beneficial effects of PSB-0777 on inflammatory parameters were prevented by the pharmacological blockade of A2A receptors. No adverse cardiovascular events were observed upon PSB-0777 administration. The novel A2A receptor agonist PSB-0777 could represent the base for the development of innovative pharmacological entities able to act in an event-specific and site-specific manner.
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Affiliation(s)
- L Antonioli
- Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - A El-Tayeb
- PharmaCenter Bonn, Pharmaceutical Sciences Bonn (PSB), Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Bonn, Germany
| | - C Pellegrini
- Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - M Fornai
- Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 55, 56126, Pisa, Italy.
| | - O Awwad
- Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - G Giustarini
- Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - G Natale
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - L Ryskalin
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Z H Németh
- Department of Surgery, Morristown Medical Center, Morristown, NJ, USA
| | - C E Müller
- PharmaCenter Bonn, Pharmaceutical Sciences Bonn (PSB), Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Bonn, Germany
| | - C Blandizzi
- Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 55, 56126, Pisa, Italy
| | - R Colucci
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
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Abstract
Clostridium difficile is an anaerobic, Gram-positive, spore-forming, toxin-secreting bacillus that has long been recognized to be the most common etiologic pathogen of antibiotic-associated diarrhea. C. difficile infection (CDI) is now the most common cause of health care-associated infections in the United States and accounts for 12% of these infections (Magill SS et al., N Engl J Med370:1198-1208, 2014). Among emerging pathogens of public health importance in the United States, CDI has the highest population-based incidence, estimated at 147 per 100,000 (Lessa FC et al., N Engl J Med372:825-834, 2015). In a report on antimicrobial resistance, C. difficile has been categorized by the Centers for Disease Control and Prevention as one of three "urgent" threats (http://www.cdc.gov/drugresistance/threat-report-2013/). Although C. difficile was first described in the late 1970s, the past decade has seen the emergence of hypertoxigenic strains that have caused increased morbidity and mortality worldwide. Pathogenic strains, host susceptibility, and other regional factors vary and may influence the clinical manifestation and approach to intervention. In this article, we describe the global epidemiology of CDI featuring the different strains in circulation outside of North America and Europe where strain NAP1/027/BI/III had originally gained prominence. The elderly population in health care settings has been disproportionately affected, but emergence of CDI in children and healthy young adults in community settings has, likewise, been reported. New approaches in management, including fecal microbiota transplantation, are discussed.
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Fehér C, Soriano A, Mensa J. A Review of Experimental and Off-Label Therapies for Clostridium difficile Infection. Infect Dis Ther 2017; 6:1-35. [PMID: 27910000 PMCID: PMC5336415 DOI: 10.1007/s40121-016-0140-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Indexed: 12/16/2022] Open
Abstract
In spite of increased awareness and the efforts taken to optimize Clostridium difficile infection (CDI) management, with the limited number of currently available antibiotics for C. difficile the halt of this increasing epidemic remains out of reach. There are, however, close to 80 alternative treatment methods with controversial anti-clostridial efficacy or in experimental phase today. Indeed, some of these therapies are expected to become acknowledged members of the recommended anti-CDI arsenal within the next few years. None of these alternative treatment methods can respond in itself to all the major challenges of CDI management, which are primary prophylaxis in the susceptible population, clinical cure of severe cases, prevention of recurrences, and forestallment of asymptomatic C. difficile carriage and in-hospital spread. Yet, the greater the variety of treatment choices on hand, the better combination strategies can be developed to reach these goals in the future. The aim of this article is to provide a comprehensive summary of these experimental and currently off-label therapeutic options.
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Affiliation(s)
- Csaba Fehér
- Department of Infectious Diseases, Hospital Clínic of Barcelona, Barcelona, Spain.
| | - Alex Soriano
- Department of Infectious Diseases, Hospital Clínic of Barcelona, Barcelona, Spain
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
- University of Barcelona, Barcelona, Spain
| | - Josep Mensa
- Department of Infectious Diseases, Hospital Clínic of Barcelona, Barcelona, Spain
- August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Barcelona, Spain
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van Waarde A, Dierckx RAJO, Zhou X, Khanapur S, Tsukada H, Ishiwata K, Luurtsema G, de Vries EFJ, Elsinga PH. Potential Therapeutic Applications of Adenosine A 2A Receptor Ligands and Opportunities for A 2A Receptor Imaging. Med Res Rev 2017; 38:5-56. [PMID: 28128443 DOI: 10.1002/med.21432] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/31/2016] [Accepted: 11/14/2016] [Indexed: 12/13/2022]
Abstract
Adenosine A2A receptors (A2A Rs) are highly expressed in the human striatum, and at lower densities in the cerebral cortex, the hippocampus, and cells of the immune system. Antagonists of these receptors are potentially useful for the treatment of motor fluctuations, epilepsy, postischemic brain damage, or cognitive impairment, and for the control of an immune checkpoint during immunotherapy of cancer. A2A R agonists may suppress transplant rejection and graft-versus-host disease; be used to treat inflammatory disorders such as asthma, inflammatory bowel disease, and rheumatoid arthritis; be locally applied to promote wound healing and be employed in a strategy for transient opening of the blood-brain barrier (BBB) so that therapeutic drugs and monoclonal antibodies can enter the brain. Increasing A2A R signaling in adipose tissue is also a potential strategy to combat obesity. Several radioligands for positron emission tomography (PET) imaging of A2A Rs have been developed in recent years. This review article presents a critical overview of the potential therapeutic applications of A2A R ligands, the use of A2A R imaging in drug development, and opportunities and limitations of PET imaging in future research.
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Affiliation(s)
- Aren van Waarde
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Rudi A J O Dierckx
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands.,Department of Nuclear Medicine, University Hospital, Ghent University, De Pintelaan 185, 9000, Ghent, Belgium
| | - Xiaoyun Zhou
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Shivashankar Khanapur
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Hideo Tsukada
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamakita, Hamamatsu, Shizuoka 434-8601, Japan
| | - Kiichi Ishiwata
- Research Institute of Cyclotron and Drug Discovery Research, Southern TOHOKU Research Institute for Neuroscience, 7-115 Yatsuyamada, Koriyama, 963-8052, Japan.,Department of Biofunctional Imaging, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan.,Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Gert Luurtsema
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Erik F J de Vries
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
| | - Philip H Elsinga
- University of Groningen, University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, 1, 9713 GZ, Groningen, The Netherlands
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Abstract
Clostridium difficile infection (CDI) is the most common infectious cause of healthcare-acquired diarrhoea. Outcomes of C. difficile colonization are varied, from asymptomatic carriage to fulminant colitis and death, due in part to the interplay between the pathogenic virulence factors of the bacterium and the counteractive immune responses of the host. Secreted toxins A and B are the major virulence factors of C. difficile and induce a profound inflammatory response by intoxicating intestinal epithelial cells causing proinflammatory cytokine release. Host cell necrosis, vascular permeability and neutrophil infiltration lead to an elevated white cell count, profuse diarrhoea and in severe cases, dehydration, hypoalbuminaemia and toxic megacolon. Other bacterial virulence factors, including surface layer proteins and flagella proteins, are detected by host cell surface signal molecules that trigger downstream cell-mediated immune pathways. Human studies have identified a role for serum and faecal immunoglobulin levels in protection from disease, but the recent development of a mouse model of CDI has enabled studies into the precise molecular interactions that trigger the immune response during infection. Key effector molecules have been identified that can drive towards a protective anti-inflammatory response or a damaging proinflammatory response. The limitations of current antimicrobial therapies for CDI have led to the development of both active and passive immunotherapies, none of which have, as yet been formally approved for CDI. However, recent advances in our understanding of the molecular basis of host immune protection against CDI may provide an exciting opportunity for novel therapeutic developments in the future.
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Affiliation(s)
- Katie Solomon
- School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Republic of Ireland
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Antonioli L, Csóka B, Fornai M, Colucci R, Kókai E, Blandizzi C, Haskó G. Adenosine and inflammation: what's new on the horizon? Drug Discov Today 2014; 19:1051-68. [DOI: 10.1016/j.drudis.2014.02.010] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 02/06/2014] [Accepted: 02/25/2014] [Indexed: 12/18/2022]
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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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de Lera Ruiz M, Lim YH, Zheng J. Adenosine A2A Receptor as a Drug Discovery Target. J Med Chem 2013; 57:3623-50. [DOI: 10.1021/jm4011669] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Manuel de Lera Ruiz
- Department
of Chemical Research, Merck Research Laboratories, 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Yeon-Hee Lim
- Department
of Chemical Research, Merck Research Laboratories, 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Junying Zheng
- Department
of Chemical Research, Merck Research Laboratories, 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
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Patrick Schenck L, Hirota SA, Hirota CL, Boasquevisque P, Tulk SE, Li Y, Wadhwani A, Doktorchik CTA, MacNaughton WK, Beck PL, MacDonald JA, MacDonald JA. Attenuation of Clostridium difficile toxin-induced damage to epithelial barrier by ecto-5'-nucleotidase (CD73) and adenosine receptor signaling. Neurogastroenterol Motil 2013; 25:e441-53. [PMID: 23600886 DOI: 10.1111/nmo.12139] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 03/25/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND Clostridium difficile (Cdf) releases toxins (TcdA and TcdB) that damage the intestinal epithelial barrier. Ecto-5'-nucleotidase (CD73) is expressed on intestinal epithelial cells, and it is hypothesized to protect against toxin-induced epithelial damage through the cleavage of 5'-AMP to adenosine (Ado) and subsequent activation of adenosine receptors (AdoRs). Herein, we sought to assess the potential protective effects of CD73 and AdoR signaling on the injurious effects of Cdf toxins. METHODS Barrier function was assessed with T84 colonocytes. Transepithelial electrical resistance (TEER), paracellular fluorescein isothiocyanate (FITC)-dextran flux, and tight junction protein (ZO-1) integrity were monitored. Intrarectal installation of Cdf toxin was used to assess epithelial damage in vivo. KEY RESULTS TcdA/B caused reduced TEER and increased paracellular flux in vitro. Concurrent treatment with 5'-AMP attenuated these responses to Cdf toxin; an effect that was blocked with ZM241385 (AdoRA2 antagonist). APCP, a CD73 inhibitor, also suppressed the protective effects of 5'-AMP on paracellular flux. 5'-AMP reduced toxin-induced disruption of ZO-1, an effect that was abolished by APCP and ZM241385. Inhibition of CD73 with APCP during Cdf toxin exposure led to increased intestinal barrier permeability and epithelial damage in vivo. Intrarectal instillation of 5'-AMP had no effect on toxin-induced intestinal injury. CONCLUSIONS & INFERENCES Our data suggest that CD73 has a protective role against TcdA/B-induced damage. 5'-AMP treatment attenuated the damaging effects of Cdf toxin in vitro, and inhibitors of CD73 (APCP) and AdoRs (ZM241385) revealed that the cleavage of 5'-AMP to Ado was necessary for the protective effects. Inhibition of CD73 in vivo increases colonic tissue damage and epithelial permeability during Cdf toxin exposure.
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Affiliation(s)
| | | | - C. L. Hirota
- Department of Physiology & Pharmacology; University of Calgary; Calgary; AB; Canada; T2N 4Z6
| | | | - S. E. Tulk
- Department of Biochemistry & Molecular Biology; University of Calgary; Calgary; AB; Canada; T2N 4Z6
| | - Y. Li
- Department of Medicine; University of Calgary; Calgary; AB; Canada; T2N 4Z6
| | - A. Wadhwani
- Department of Physiology & Pharmacology; University of Calgary; Calgary; AB; Canada; T2N 4Z6
| | - C. T. A. Doktorchik
- Department of Biochemistry & Molecular Biology; University of Calgary; Calgary; AB; Canada; T2N 4Z6
| | - W. K. MacNaughton
- Department of Physiology & Pharmacology; University of Calgary; Calgary; AB; Canada; T2N 4Z6
| | - P. L. Beck
- Department of Medicine; University of Calgary; Calgary; AB; Canada; T2N 4Z6
| | - J. A. MacDonald
- Department of Biochemistry & Molecular Biology; University of Calgary; Calgary; AB; Canada; T2N 4Z6
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19
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Xiao H, Si LY, Liu W, Li N, Meng G, Yang N, Chen X, Zhou YG, Shen HY. The effects of adenosine A2A receptor knockout on renal interstitial fibrosis in a mouse model of unilateral ureteral obstruction. Acta Histochem 2013; 115:315-9. [PMID: 23026406 DOI: 10.1016/j.acthis.2012.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/30/2012] [Accepted: 09/05/2012] [Indexed: 11/15/2022]
Abstract
Adenosine A2A receptor (A2AR) plays an important regulatory role in the processes of inflammation and fibrosis. However, it is unknown whether A2AR can mediate renal interstitial fibrosis (RIF). To evaluate the effect of genetic A2AR knockout (KO) on the pathological progress of RIF, we applied a unilateral ureteral obstruction (UUO) model of RIF on A2AR KO mice and their wild-type (WT) littermates. Renal pathological assessment was performed at different post-UUO stages using hematoxylin and eosin (H&E) and Masson's trichrome staining as well as quantitative morphological analysis. Our data demonstrated that: (i) the extent of RIF was determined by the development of UUO in a time-dependent manner; (ii) A2AR KO exacerbated the pathological progress of RIF in mice at the early post-UUO stage, i.e. day 3 and day 7; (iii) the profibrotic effect of A2AR KO was prominent until the late post-UUO stage, i.e. day 14, at which RIF reached a similar severity level in A2AR KO and WT mice. Our findings revealed that A2AR KO significantly exacerbated the progression of UUO-induced RIF in mice, prominently at the initial stage.
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Affiliation(s)
- Hang Xiao
- Molecular Biology Center, State Key Laboratory of Trauma, Burns, and Combined Injury, Research Institute of Surgery and Daping Hospital, Third Military Medical University, Chongqing 400042, China
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20
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Rodrigues RS, Oliveira RAC, Li Y, Zaja-Milatovic S, Costa LB, Braga Neto MB, Kolling GL, Lima AA, Guerrant RL, Warren CA. Intestinal epithelial restitution after TcdB challenge and recovery from Clostridium difficile infection in mice with alanyl-glutamine treatment. J Infect Dis 2013; 207:1505-15. [PMID: 23359592 DOI: 10.1093/infdis/jit041] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Clostridium difficile is an anaerobic bacterium that causes antibiotic-associated diarrhea. It produces toxin A and toxin B (TcdB), which cause injury to the gut epithelium. Glutamine is a fundamental fuel for enterocytes, maintaining intestinal mucosal health. Alanyl-glutamine (AQ) is a highly soluble dipeptide derivative of glutamine. We studied whether administration of AQ ameliorates the effects of TcdB in the intestinal cells and improves the outcome of C. difficile infection in mice. METHODS WST-1 proliferation and cell-wounding-migration assays were assessed in IEC-6 cells exposed to TcdB, with or without AQ. Apoptosis and necrosis were assessed using Annexin V and flow cytometry. C57BL/6 mice were infected with VPI 10463 and treated with either vancomycin, AQ, or vancomycin with AQ. Intestinal tissues were collected for histopathologic analysis, apoptosis staining, and determination of myeloperoxidase activity. RESULTS AQ increased proliferation in intestinal cells exposed to TcdB, improved migration at 24 and 48 hours, and reduced apoptosis in intestinal cells challenged with TcdB. Infected mice treated with vancomycin and AQ had better survival and histopathologic findings than mice treated with vancomycin alone. CONCLUSIONS AQ may reduce intestinal mucosal injury in C. difficile-infected mice by partially reversing the effects of TcdB on enterocyte proliferation, migration, and apoptosis, thereby improving survival from C. difficile infection.
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Li Y, Figler RA, Kolling G, Bracken TC, Rieger J, Stevenson RW, Linden J, Guerrant RL, Warren CA. Adenosine A2A receptor activation reduces recurrence and mortality from Clostridium difficile infection in mice following vancomycin treatment. BMC Infect Dis 2012; 12:342. [PMID: 23217055 PMCID: PMC3523970 DOI: 10.1186/1471-2334-12-342] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 12/03/2012] [Indexed: 11/10/2022] Open
Abstract
Background Activation of the A2A adenosine receptor (A2AAR) decreases production of inflammatory cytokines, prevents C. difficile toxin A-induced enteritis and, in combination with antibiotics, increases survival from sepsis in mice. We investigated whether A2AAR activation improves and A2AAR deletion worsens outcomes in a murine model of C. difficile (strain VPI10463) infection (CDI). Methods C57BL/6 mice were pretreated with an antibiotic cocktail prior to infection and then treated with vancomycin with or without an A2AAR agonist. A2AAR-/- and littermate wild-type (WT) mice were similarly infected, and IFNγ and TNFα were measured at peak of and recovery from infection. Results Infected, untreated mice rapidly lost weight, developed diarrhea, and had mortality rates of 50-60%. Infected mice treated with vancomycin had less weight loss and diarrhea during antibiotic treatment but mortality increased to near 100% after discontinuation of antibiotics. Infected mice treated with both vancomycin and an A2AAR agonist, either ATL370 or ATL1222, had minimal weight loss and better long-term survival than mice treated with vancomycin alone. A2AAR KO mice were more susceptible than WT mice to death from CDI. Increases in cecal IFNγ and blood TNFα were pronounced in the absence of A2AARs. Conclusion In a murine model of CDI, vancomycin treatment resulted in reduced weight loss and diarrhea during acute infection, but high recurrence and late-onset death, with overall mortality being worse than untreated infected controls. The administration of vancomycin plus an A2AAR agonist reduced inflammation and improved survival rates, suggesting a possible benefit of A2AAR agonists in the management of CDI to prevent recurrent disease.
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Affiliation(s)
- Yuesheng Li
- Division of Infectious Diseases and International Health, Carter Harrison Bldg, Charlottesville, VA 22908, USA
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Contribution of adenosine A(2B) receptors in Clostridium difficile intoxication and infection. Infect Immun 2012; 80:4463-73. [PMID: 23045479 DOI: 10.1128/iai.00782-12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Clostridium difficile toxins A (TcdA) and B (TcdB) induce a pronounced systemic and intestinal inflammatory response. A(2B) adenosine receptors (A(2B)ARs) are the predominant adenosine receptors in the intestinal epithelium. We investigated whether A(2B)ARs are upregulated in human intestinal cells by TcdA or TcdB and whether blockade of A(2B)ARs can ameliorate C. difficile TcdA-induced enteritis and alter the outcome of C. difficile infection (CDI). Adenosine receptor subtype (A(1), A(2A), A(2B), and A(3)) mRNAs were assayed in HCT-8 cells. Ileal loops from wild-type rabbits and mice and A(2B)AR(-/-) mice were treated with TcdA, with or without the selective A(2B)AR antagonist ATL692 or PSB1115. A murine model of CDI was used to determine the effect of A(2B)AR deletion or blockade with the orally available agent ATL801, on clinical outcome, histopathology and intestinal interleukin-6 (IL-6) expression from infection. TcdA and TcdB upregulated A(2B)AR gene expression in HCT-8 cells. ATL692 decreased TcdA-induced secretion and epithelial injury in rabbit ileum. Deletion of A(2B)ARs reduced secretion and histopathology in TcdA-challenged mouse ileum. Deletion or blockade of A(2B)ARs reduced histopathology, IL-6 expression, weight loss, diarrhea, and mortality in C. difficile-infected mice. A(2B)ARs mediate C. difficile toxin-induced enteritis and disease. Inhibition of A(2B)AR activation may be a potential strategy to limit morbidity and mortality from CDI.
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