title: Human Clostridium difficile infection: inhibition of NHE3 and microbiota profile.
abstract: Clostridium difficile infection (CDI) is principally responsible for hospital acquired, antibiotic-induced diarrhea and colitis and represents a significant financial burden on our healthcare system. Little is known about C. difficile proliferation requirements, and a better understanding of these parameters is critical for development of new therapeutic targets. In cell lines, C. difficile toxin B has been shown to inhibit Na(+)/H(+) exchanger 3 (NHE3) and loss of NHE3 in mice results in an altered intestinal environment coupled with a transformed gut microbiota composition. However, this has yet to be established in vivo in humans. We hypothesize that C. difficile toxin inhibits NHE3, resulting in alteration of the intestinal environment and gut microbiota. Our results demonstrate that CDI patient biopsy specimens have decreased NHE3 expression and CDI stool has elevated Na(+) and is more alkaline compared with stool from healthy individuals. CDI stool microbiota have increased Bacteroidetes and Proteobacteria and decreased Firmicutes phyla compared with healthy subjects. In vitro, C. difficile grows optimally in the presence of elevated Na(+) and alkaline pH, conditions that correlate to changes observed in CDI patients. To confirm that inhibition of NHE3 was specific to C. difficile, human intestinal organoids (HIOs) were injected with C. difficile or healthy and CDI stool supernatant. Injection of C. difficile and CDI stool decreased NHE3 mRNA and protein expression compared with healthy stool and control HIOs. Together these data demonstrate that C. difficile inhibits NHE3 in vivo, which creates an altered environment favored by C. difficile.
authors.affiliation: Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio;
authors.forename: Melinda A
authors.initials: MA
authors.lastname: Engevik
authors.affiliation: Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio;
authors.forename: Kristen A
authors.initials: KA
authors.lastname: Engevik
authors.affiliation: Department of Medicine Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio;
authors.forename: Mary Beth
authors.initials: MB
authors.lastname: Yacyshyn
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio;
authors.forename: Jiang
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio;
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hassett
authors.affiliation: Department of Animal Health and Biomedical Sciences, University Wisconsin, Madison, Wisconsin; and.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Darien
authors.affiliation: Department of Medicine Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio; Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Yacyshyn
authors.affiliation: Department of Molecular and Cellular Physiology, University of Cincinnati College of Medicine, Cincinnati, Ohio; Digestive Health Center of Cincinnati Children's Hospital, Cincinnati, Ohio Roger.Worrell@uc.edu.
authors.forename: Roger T
authors.initials: RT
authors.lastname: Worrell
mesh_terms: D000328:Adult; D000368:Aged; D001426:Bacterial Proteins / Q000378:metabolism; D001427:Bacterial Toxins / Q000378:metabolism; D016022:Case-Control Studies; D002478:Cells, Cultured; D016360:Clostridioides difficile / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism; D003106:Colon / Q000378:metabolism* / Q000382:microbiology*; D015536:Down-Regulation; D004761:Enterocolitis, Pseudomembranous / Q000378:metabolism* / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D054884:Host-Pathogen Interactions; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007413:Intestinal Mucosa / Q000378:metabolism / Q000382:microbiology; D008297:Male; D064307:Microbiota; D008875:Middle Aged; D009940:Organoids; D039904:Pluripotent Stem Cells / Q000378:metabolism / Q000382:microbiology; D012333:RNA, Messenger / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D012333:RNA, Messenger; C000613385:SLC9A3 protein, human; C000613386:Slc9a3 protein, mouse; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; C031815:toxB protein, Clostridium difficile; D012964:Sodium
keywords: C. difficile; NHE3; diarrhea; gut microbiota; intestinal organoids