Genetically engineered bacteria expressing IL-34 alleviate DSS-induced experimental colitis by promoting tight junction protein expression in intestinal mucosal epithelial cells

  • Mol Immunol. 2025 Feb:178:64-75. doi: 10.1016/j.molimm.2025.01.008.
Weijie Chen  1 ,  Tongtong Zhou  2 ,  Yicun Liu  3 ,  Leilei Luo  4 ,  Yujing Ye  5 ,  Lixian Wei  6 ,  Jian Chen  7 ,  Zhaolian Bian  8
Affiliations
  • 1. Medical School, Nantong University, Nantong, Jiangsu Province 226001, China. Electronic address: [email protected].
  • 2. Medical School, Nantong University, Nantong, Jiangsu Province 226001, China. Electronic address: [email protected].
  • 3. Department of Gastroenterology and Hepatology, Nantong Third People's Hospital, Affiliated Nantong Hospital 3 of Nantong University, Nantong, Jiangsu Province 226006, China. Electronic address: [email protected].
  • 4. Department of Gastroenterology and Hepatology, Nantong Third People's Hospital, Affiliated Nantong Hospital 3 of Nantong University, Nantong, Jiangsu Province 226006, China. Electronic address: [email protected].
  • 5. Medical School, Nantong University, Nantong, Jiangsu Province 226001, China. Electronic address: [email protected].
  • 6. Department of Gastroenterology and Hepatology, Nantong Third People's Hospital, Affiliated Nantong Hospital 3 of Nantong University, Nantong, Jiangsu Province 226006, China. Electronic address: [email protected].
  • 7. Department of Gastroenterology and Hepatology, Nantong Third People's Hospital, Affiliated Nantong Hospital 3 of Nantong University, Nantong, Jiangsu Province 226006, China. Electronic address: [email protected].
  • 8. Department of Gastroenterology and Hepatology, Nantong Third People's Hospital, Affiliated Nantong Hospital 3 of Nantong University, Nantong, Jiangsu Province 226006, China. Electronic address: [email protected].
PMID: 39864284 DOI: 10.1016/j.molimm.2025.01.008
Abstract

Background: The intestinal mucosa of Ulcerative Colitis patients expresses high levels of interleukin 34, and mice lacking IL-34 have more severe DSS-induced experimental Colitis. There are no studies on the effects of directly upregulating intestinal IL-34 on experimental Colitis in mice.

Methods: The bacteria EcN/CSF-1 and EcN/IL-34, which express CSF-1 and IL-34, respectively, were genetically engineered from Escherichia coli Nissle 1917 (EcN). Colitis mice received daily gavage of sterile PBS buffer, empty plasmid E. coli (EcN/WT), EcN/CSF-1, or EcN/IL-34. Each group of mice was assessed for body mass, clinical signs, DAI, intestinal mucosal permeability, pathological, and immunohistological changes. In vitro, NCM460 cells were treated with CSF-1 or IL-34 Recombinant proteins in the presence of signaling pathway inhibitors to evaluate tight junction protein expression. Additionally, intestinal mucosal epithelial cells isolated from active UC patients were analyzed for IL-34 and tight junction protein levels.

Results: DSS-induced Colitis mice are protected by EcN/IL-34 gavage. Pathological results showed that EcN/IL-34 group colonic histological injury was significantly improved and tight junction protein ZO-1 and Occludin expression increased. In NCM460 cells, IL-34 also increased tight junction protein expression. More importantly, expression of IL-34 was positively correlated with the level of tight junction protein expression in epithelial cells of UC patients.

Conclusion: EcN/IL-34 can directly act on damaged intestinal mucosa, up-regulate IL-34 expression, and promote tight junction protein expression in intestinal mucosal epithelial cells to alleviate experimental Colitis in mice. IL-34 may be a potential therapeutic target for Ulcerative Colitis, and genetically engineered bacteria carrying the cytokine may offer new ideas for treating UC.

Keywords
Escherichia coli Nissle1917; Genetically engineered bacteria; Inflammatory bowel disease; Interleukin-34; Intestinal mucosal barrier; Tight junction protein.
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