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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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Siddiqi U, Lunnemann HM, Childress KO, Shupe JA, Rutherford SA, Farrow MA, Washington MK, Coffey RJ, Lacy DB, Markham NO. Inhibition of EGFR/ErbB does not protect against C. difficile toxin B. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.594035. [PMID: 38798529 PMCID: PMC11118545 DOI: 10.1101/2024.05.13.594035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Clostridioides difficile is a common cause of diarrhea and mortality, especially in immunosuppressed and hospitalized patients. C. difficile is a toxin-mediated disease, but the host cell receptors for C. difficile toxin B (TcdB) have only recently been revealed. Emerging data suggest TcdB interacts with receptor tyrosine kinases during infection. In particular, TcdB can elicit Epidermal Growth Factor Receptor (EGFR) transactivation in human colonic epithelial cells. The mechanisms for this function are not well understood, and the involvement of other receptors in the EGFR family of Erythroblastic Leukemia Viral Oncogene Homolog (ErbB) receptors remains unclear. Furthermore, in an siRNA-knockdown screen for protective genes involved with TcdB toxin pathogenesis, we show ErbB2 and ErbB3 loss resulted in increased cell viability. We hypothesize TcdB induces the transactivation of EGFR and/or ErbB receptors as a component of its cell-killing mechanism. Here, we show in vivo intrarectal instillation of TcdB in mice leads to phosphorylation of ErbB2 and ErbB3. However, immunohistochemical staining for phosphorylated ErbB2 and ErbB3 indicated no discernible difference between control and TcdB-treated mice for epithelial phospho-ErbB2 and phospho-ErbB3. Human colon cancer cell lines (HT29, Caco-2) exposed to TcdB were not protected by pre-treatment with lapatinib, an EGFR/ErbB2 inhibitor. Similarly, lapatinib pre-treatment failed to protect normal human colonoids from TcdB-induced cell death. Neutralizing antibodies against mouse EGFR failed to protect mice from TcdB intrarectal instillation as measured by edema, inflammatory infiltration, and epithelial injury. Our findings suggest TcdB-induced colonocyte cell death does not require EGFR/ErbB receptor tyrosine kinase activation.
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3
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Fettucciari K, Spaterna A, Marconi P, Bassotti G. Pro-Inflammatory Cytokines Enhanced In Vitro Cytotoxic Activity of Clostridioides difficile Toxin B in Enteric Glial Cells: The Achilles Heel of Clostridioides difficile Infection? Int J Mol Sci 2024; 25:958. [PMID: 38256032 PMCID: PMC10815653 DOI: 10.3390/ijms25020958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/24/2024] Open
Abstract
Bacterial infections are characterized by an inflammatory response, which is essential for infection containment but is also responsible for negative effects on the host. The pathogen itself may have evolved molecular mechanisms to antagonize the antimicrobial effects of an inflammatory response and to enhance its pathogenicity using inflammatory response mediators, such as cytokines. Clostridioides difficile (C. difficile) infection (CDI) causes gastrointestinal diseases with markedly increasing global incidence and mortality rates. The main C. difficile virulence factors, toxin A and B (TcdA/TcdB), cause cytopathic/cytotoxic effects and inflammation. We previously demonstrated that TcdB induces enteric glial cell (EGC) apoptosis, which is enhanced by the pro-inflammatory cytokine tumor necrosis factor alpha plus interferon gamma (CKs). However, it is unknown whether CKs-enhanced TcdB cytotoxicity (apoptosis/necrosis) is affected by the timing of the appearance of the CKs. Thus, we simulated in vitro, in our experimental model with TcdB and EGCs, three main situations of possible interactions between TcdB and the timing of CK stimulation: before TcdB infection, concomitantly with infection, or at different times after infection and persisting over time. In these experimental conditions, which all represent situations of possible interactions between C. difficile and the timing of CK stimulation, we evaluated apoptosis, necrosis, and cell cycle phases. The CKs, in all of these conditions, enhanced TcdB cytotoxicity, which from apoptosis became necrosis when CK stimulation persisted over time, and was most relevant after 48 h of TcdB:EGCs interaction. Particularly, the enhancement of apoptosis by CKs was dependent on the TcdB dose and in a less relevant manner on the CK stimulation time, while the enhancement of necrosis occurred always independently of the TcdB dose and CK stimulation time. However, since in all conditions stimulation with CKs strongly enhanced the TcdB cytotoxicity, it always had a negative impact on C. difficile pathogenicity. This study might have important implications for the treatment of CDI.
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Affiliation(s)
- Katia Fettucciari
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy;
| | - Andrea Spaterna
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024 Macerata, Italy
| | - Pierfrancesco Marconi
- Biosciences & Medical Embryology Section, Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy;
| | - Gabrio Bassotti
- Gastroenterology, Hepatology & Digestive Endoscopy Section, Department of Medicine and Surgery, University of Perugia, 06132 Perugia, Italy;
- Gastroenterology & Hepatology Unit, Santa Maria Della Misericordia Hospital, 06129 Perugia, Italy
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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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Kordus SL, Kroh HK, Rodríguez RC, Shrem RA, Peritore-Galve FC, Shupe JA, Wadzinski BE, Lacy DB, Spiller BW. Nanobodies against C. difficile TcdA and TcdB reveal unexpected neutralizing epitopes and provide a toolkit for toxin quantitation in vivo. PLoS Pathog 2023; 19:e1011496. [PMID: 37871122 PMCID: PMC10621975 DOI: 10.1371/journal.ppat.1011496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 11/02/2023] [Accepted: 10/07/2023] [Indexed: 10/25/2023] Open
Abstract
Clostridioides difficile is a leading cause of antibiotic-associated diarrhea and nosocomial infection in the United States. The symptoms of C. difficile infection (CDI) are associated with the production of two homologous protein toxins, TcdA and TcdB. The toxins are considered bona fide targets for clinical diagnosis as well as the development of novel prevention and therapeutic strategies. While there are extensive studies that document these efforts, there are several gaps in knowledge that could benefit from the creation of new research tools. First, we now appreciate that while TcdA sequences are conserved, TcdB sequences can vary across the span of circulating clinical isolates. An understanding of the TcdA and TcdB epitopes that drive broadly neutralizing antibody responses could advance the effort to identify safe and effective toxin-protein chimeras and fragments for vaccine development. Further, an understanding of TcdA and TcdB concentration changes in vivo can guide research into how host and microbiome-focused interventions affect the virulence potential of C. difficile. We have developed a panel of alpaca-derived nanobodies that bind specific structural and functional domains of TcdA and TcdB. We note that many of the potent neutralizers of TcdA bind epitopes within the delivery domain, a finding that could reflect roles of the delivery domain in receptor binding and/or the conserved role of pore-formation in the delivery of the toxin enzyme domains to the cytosol. In contrast, neutralizing epitopes for TcdB were found in multiple domains. The nanobodies were also used for the creation of sandwich ELISA assays that allow for quantitation of TcdA and/or TcdB in vitro and in the cecal and fecal contents of infected mice. We anticipate these reagents and assays will allow researchers to monitor the dynamics of TcdA and TcdB production over time, and the impact of various experimental interventions on toxin production in vivo.
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Affiliation(s)
- Shannon L. Kordus
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Heather K. Kroh
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Rubén Cano Rodríguez
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Rebecca A. Shrem
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - F. Christopher Peritore-Galve
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - John A. Shupe
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Brian E. Wadzinski
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - D. Borden Lacy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
| | - Benjamin W. Spiller
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, United States of America
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Mavrogeni ME, Asadpoor M, Judernatz JH, van Ark I, Wösten MMSM, Strijbis K, Pieters RJ, Folkerts G, Braber S. Protective Effects of Alginate and Chitosan Oligosaccharides against Clostridioides difficile Bacteria and Toxin. Toxins (Basel) 2023; 15:586. [PMID: 37888617 PMCID: PMC10610568 DOI: 10.3390/toxins15100586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 09/01/2023] [Accepted: 09/12/2023] [Indexed: 10/28/2023] Open
Abstract
Clostridioides difficile infection is expected to become the most common healthcare-associated infection worldwide. C. difficile-induced pathogenicity is significantly attributed to its enterotoxin, TcdA, which primarily targets Rho-GTPases involved in regulating cytoskeletal and tight junction (TJ) dynamics, thus leading to cytoskeleton breakdown and ultimately increased intestinal permeability. This study investigated whether two non-digestible oligosaccharides (NDOs), alginate (AOS) and chitosan (COS) oligosaccharides, possess antipathogenic and barrier-protective properties against C. difficile bacteria and TcdA toxin, respectively. Both NDOs significantly reduced C. difficile growth, while cell cytotoxicity assays demonstrated that neither COS nor AOS significantly attenuated the TcdA-induced cell death 24 h post-exposure. The challenge of Caco-2 monolayers with increasing TcdA concentrations increased paracellular permeability, as measured by TEER and LY flux assays. In this experimental setup, COS completely abolished, and AOS mitigated, the deleterious effects of TcdA on the monolayer's integrity. These events were not accompanied by alterations in ZO-1 and occludin protein levels; however, immunofluorescence microscopy revealed that both AOS and COS prevented the TcdA-induced occludin mislocalization. Finally, both NDOs accelerated TJ reassembly upon a calcium-switch assay. Overall, this study established the antipathogenic and barrier-protective capacity of AOS and COS against C. difficile and its toxin, TcdA, while revealing their ability to promote TJ reassembly in Caco-2 cells.
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Affiliation(s)
- Maria Eleni Mavrogeni
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Mostafa Asadpoor
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Jo H Judernatz
- Structural Biochemistry Group, Bijvoet Centre for Biomolecular Research, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Ingrid van Ark
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Marc M S M Wösten
- Division of Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands
| | - Karin Strijbis
- Division of Infectious Diseases and Immunology, Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands
| | - Roland J Pieters
- Division of Medicinal Chemistry and Chemical Biology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Gert Folkerts
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Saskia Braber
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
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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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Larabee JL, Doyle DA, Ahmed UKB, Shadid TM, Sharp RR, Jones KL, Kim YM, Li S, Ballard JD. Discovery of Hippo signaling as a regulator of CSPG4 expression and as a therapeutic target for Clostridioides difficile disease. PLoS Pathog 2023; 19:e1011272. [PMID: 36972308 PMCID: PMC10079225 DOI: 10.1371/journal.ppat.1011272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 04/06/2023] [Accepted: 03/08/2023] [Indexed: 03/29/2023] Open
Abstract
The signaling pathways and networks regulating expression of chondroitin sulfate proteoglycan 4 (CSPG4), a cancer-related protein that serves as a receptor for Clostridiodes difficile TcdB, are poorly defined. In this study, TcdB-resistant/CSPG4-negative HeLa cells were generated by exposure to increasing concentrations of the toxin. The cells that emerged (HeLa R5) lost expression of CSPG4 mRNA and were resistant to binding by TcdB. mRNA expression profiles paired with integrated pathway analysis correlated changes in the Hippo and estrogen signaling pathways with a CSPG4 decrease in HeLa R5 cells. Both signaling pathways altered CSPG4 expression when modulated chemically or through CRISPR-mediated deletion of key transcriptional regulators in the Hippo pathway. Based on the in vitro findings, we predicted and experimentally confirmed that a Hippo pathway inactivating drug (XMU-MP-1) provides protection from C. difficile disease in a mouse model. These results provide insights into key regulators of CSPG4 expression and identify a therapeutic for C. difficile disease.
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Affiliation(s)
- Jason L. Larabee
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - D. Annie Doyle
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Ummey Khalecha Bintha Ahmed
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Tyler M. Shadid
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Rachel R. Sharp
- Laboratory for Molecular Biology and Cytometry Research, Harold Hamm Diabetes Center, Oklahoma City, Oklahoma, United States of America
| | - Kenneth L. Jones
- Laboratory for Molecular Biology and Cytometry Research, Harold Hamm Diabetes Center, Oklahoma City, Oklahoma, United States of America
- Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Young Mi Kim
- Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Shibo Li
- Department of Pediatrics, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Jimmy D. Ballard
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
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Peritore-Galve FC, Kaji I, Smith A, Walker LM, Shupe JA, Washington MK, Algood HMS, Dudeja PK, Goldenring JR, Lacy DB. Increased intestinal permeability and downregulation of absorptive ion transporters Nhe3, Dra, and Sglt1 contribute to diarrhea during Clostridioides difficile infection. Gut Microbes 2023; 15:2225841. [PMID: 37350393 PMCID: PMC10291935 DOI: 10.1080/19490976.2023.2225841] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 06/09/2023] [Indexed: 06/24/2023] Open
Abstract
BACKGROUND & AIM Clostridioides difficile infection (CDI) is the leading cause of hospital-acquired diarrhea and pseudomembranous colitis. Two protein toxins, TcdA and TcdB, produced by C. difficile are the major determinants of disease. However, the pathophysiological causes of diarrhea during CDI are not well understood. Here, we investigated the effects of C. difficile toxins on paracellular permeability and apical ion transporters in the context of an acute physiological infection. METHODS We studied intestinal permeability and apical membrane transporters in female C57BL/6J mice. Üssing chambers were used to measure paracellular permeability and ion transporter function across the intestinal tract. Infected intestinal tissues were analyzed by immunofluorescence microscopy and RNA-sequencing to uncover mechanisms of transporter dysregulation. RESULTS Intestinal permeability was increased through the size-selective leak pathway in vivo during acute CDI in a 2-day-post infection model. Chloride secretory activity was reduced in the cecum and distal colon during infection by decreased CaCC and CFTR function, respectively. SGLT1 activity was significantly reduced in the cecum and colon, accompanied by ablated SGLT1 expression in colonocytes and increased luminal glucose concentrations. SGLT1 and DRA expression was ablated by either TcdA or TcdB during acute infection, but NHE3 was decreased in a TcdB-dependent manner. The localization of key proteins that link filamentous actin to the ion transporters in the apical plasma membrane was unchanged. However, Sglt1, Nhe3, and Dra were drastically reduced at the transcript level, implicating downregulation of ion transporters in the mechanism of diarrhea during CDI. CONCLUSIONS CDI increases intestinal permeability and decreases apical abundance of NHE3, SGLT1, and DRA. This combination likely leads to dysfunctional water and solute absorption in the large bowel, causing osmotic diarrhea. These findings provide insights into the pathophysiological mechanisms underlying diarrhea and may open novel avenues for attenuating CDI-associated diarrhea.
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Affiliation(s)
- F. Christopher Peritore-Galve
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Izumi Kaji
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Anna Smith
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lauren M. Walker
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John A. Shupe
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - M. Kay Washington
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Holly M. Scott Algood
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Pradeep K. Dudeja
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Veterans Affairs, Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA
| | - James R. Goldenring
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
- Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
- Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - D. Borden Lacy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
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