Citrulline inhibits Clostridioides difficile infection with anti-inflammatory effects

  • Cell Mol Gastroenterol Hepatol. 2025 Feb 7:101474. doi: 10.1016/j.jcmgh.2025.101474.
Ying Xie  1 ,  Sophie Irwin  2 ,  Becca Nelson  3 ,  Mieke van Daelen  4 ,  Lindsey Fontenot  5 ,  Jonathan P Jacobs  6 ,  Monica Cappelletti  7 ,  Hanping Feng  8 ,  Yiling Li  9 ,  Hon Wai Koon  10
Affiliations
  • 1. Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095; Department of Gastroenterology and Endoscopy, The First Hospital of China Medical University, Shenyang City, Liaoning Province, China. Electronic address: [email protected].
  • 2. Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095. Electronic address: [email protected].
  • 3. Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095. Electronic address: [email protected].
  • 4. Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095. Electronic address: [email protected].
  • 5. Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095. Electronic address: [email protected].
  • 6. Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095; Goodman-Luskin Microbiome Center, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095; Division of Gastroenterology, Hepatology and Parenteral Nutrition, VA Greater Los Angeles Healthcare System, Los Angeles, CA 90073. Electronic address: [email protected].
  • 7. Immunogenetics Division, Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095. Electronic address: [email protected].
  • 8. Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, MD 21201, USA. Electronic address: [email protected].
  • 9. Department of Gastroenterology and Endoscopy, The First Hospital of China Medical University, Shenyang City, Liaoning Province, China. Electronic address: [email protected].
  • 10. Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA 90095. Electronic address: [email protected].
PMID: 39923847 DOI: 10.1016/j.jcmgh.2025.101474
Abstract

Background and aims: Clostridioides difficile Infection (CDI) causes colitis and diarrhea. C. difficile bacterium produces toxins A and B, which cause intestinal inflammation. A metabolomics analysis discovered fecal metabolites with anti-inflammatory effects in CDI. We aimed to identify an anti-CDI metabolite that can inhibit CDI-mediated colitis and prevent recurrence.

Methods: Fresh human colonic tissues and primary human cells were used to determine metabolite effects. Humanized C. difficile-infected HuCD34-NCG mice and antibiotics-treated human gut microbiota-treated (ABX+HGM) hamsters were used to simulate the human environment.

Results: High-throughput screening and fecal metabolomics analysis identified anti-inflammatory metabolites. Compared to Other tested metabolites, citrulline preserved the mucosal integrity of toxin-exposed fresh human colonic tissues with reduced macrophage inflammatory protein 1 alpha (MIP-1α) and increased interleukin-10 (IL-10) expression. Oral citrulline treatment alleviated cecal inflammation in hamsters infected with C. difficile ribotype 027. This was accomplished by the augmented expression of cecal IL-10 and the diminished level of cecal MIP-1α. Citrulline and vancomycin synergistically prevented recurrence in the infected ABX+HGM hamsters. In C57BL/6J mice infected with C. difficile VPI10463, citrulline ameliorated colitis by reducing colonic Ccl3 mRNA expression. In immunologically humanized HuCD34-NCG mice infected with toxin B-expressing C. difficile ribotype 017, citrulline ameliorated colitis with increased human IL-10 expression in colonic macrophages. Citrulline suppressed MIP-1α secretion and GSK3α/β dephosphorylation in the toxin A-exposed human colonic epithelial cells and promoted IL-10 expression in toxin B-exposed human macrophages and heat shock protein 27 phosphorylation.

Conclusion: Citrulline exerts anti-inflammatory effects in the intestines against C. difficile toxins and inhibits CDI recurrence in mice and hamsters.

Keywords
inflammation; metabolite; microbiome.
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