2. Academic Validation
  3. Increased intestinal permeability and downregulation of absorptive ion transporters Nhe3, Dra, and Sglt1 contribute to diarrhea during Clostridioides difficile infection

Increased intestinal permeability and downregulation of absorptive ion transporters Nhe3, Dra, and Sglt1 contribute to diarrhea during Clostridioides difficile infection

  • Gut Microbes. 2023 Jan-Dec;15(1):2225841. doi: 10.1080/19490976.2023.2225841.
F Christopher Peritore-Galve 1 2,  Izumi Kaji 3 4,  Anna Smith 1 2,  Lauren M Walker 1 2 5,  John A Shupe 1 2,  M Kay Washington 1,  Holly M Scott Algood 1 2 6,  Pradeep K Dudeja 7 8,  James R Goldenring 2 3 4 6 9,  D Borden Lacy 1 2 6
Affiliations

Affiliations

  • 1 Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA.
  • 2 Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
  • 3 Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
  • 4 Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, USA.
  • 5 Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA.
  • 6 Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA.
  • 7 Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
  • 8 Department of Veterans Affairs, Jesse Brown Veterans Affairs Medical Center, Chicago, IL, USA.
  • 9 Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.
PMID: 37350393 DOI: 10.1080/19490976.2023.2225841
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.

Keywords

Clostridioides difficile infection; ion transport; paracellular permeability; toxins.

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