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Novel mechanism links genetic defect in IBD patients to gut leakiness

Study in mice and human tissue is the first to show how a disease mutation weakens barrier properties of epithelial cells lining the gut

Date:
September 2, 2021
Source:
University of California - Riverside
Summary:
A team of researchers has identified a novel mechanism by which loss-of-function mutations in the gene PTPN2, found in many patients with inflammatory bowel disease, or IBD, affect how intestinal epithelial cells maintain a barrier.
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FULL STORY

A team of researchers led by a biomedical scientist at the University of California, Riverside, has identified a novel mechanism by which loss-of-function mutations in the gene PTPN2, found in many patients with inflammatory bowel disease, or IBD, affect how intestinal epithelial cells maintain a barrier.

The intestinal epithelium, a single layer of cells, plays a critical role in human health by providing a barrier while also allowing nutrient and water absorption. Intestinal epithelial cells are needed for regulating immune function, communicating with the intestinal microbiota, and protecting the gut from pathogen infection -- all of which critically depend on an intact epithelial barrier.

Affecting roughly 3 million Americans, IBD is a set of chronic intestinal diseases in which the lining of the gut becomes inflamed and leaky. Increased gut leakiness has recently been confirmed to increase the risk of developing IBD.

"This new publication is a culmination of a body of work from my lab identifying how loss-of-function mutations in PTPN2 can increase gut permeability or leakiness," said Declan F. McCole, a professor of biomedical sciences in the UCR School of Medicine, who led the study published in theJournal of Clinical Investigation. The journal has selected the research paper as an "Editor's highlight."

In the study, which was conducted in mice, human cells, and tissue from IBD patients, McCole and his colleagues showed that in IBD patients carrying a loss-of-function PTPN2 mutation, the expression of claudin-2, a protein that causes loss of water and sodium into the gut and promotes diarrhea, is increased. Using mouse models, the McCole lab identified a dual mechanism that explains how claudin-2 expression increases and contributes to fluid loss.

PTPN2 typically acts as a brake on the expression of claudin-2, McCole explained. The loss-of-function mutation in PTPN2 that occurs in IBD removes this brake and allows increased fluid loss.

“此外,PTPN2也促进内源性足总ctor, called matriptase, that removes claudin-2 from the area of the cell membrane where it mediates its effects in allowing fluid loss to occur," McCole said.

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减少PTPN2活动的累积效应both mechanisms was elevated fluid loss. The researchers proved this defect could be reversed by treating cells lacking PTPN2 with recombinant -- or synthetic -- matriptase.

"Our work improves understanding of how the genetics of IBD can contribute to the altered physiology in patients that drives their symptoms," McCole said. "It also supports our related work identifying how the class of drugs, called JAK inhibitors, may be used to rescue 'leaky gut,' particularly in patients with loss-of-function mutations in the PTPN2 gene.

The study also showed that a recently identified and rare novel mutation in PTPN2, which causes gut epithelial damage in children, also increases gut epithelial leakiness -- but without causing epithelial cell death.

"This suggests that patients who develop this condition may exhibit 'leaky gut' before full-blown disease occurs," McCole said.

McCole was supported in the study by co-first authors Moorthy Krishnan and Marianne R. Spalinger of UCR, and Ronald Marchelletta of UC San Diego. Other co-authors are Anica Sayoc-Becerra, Vinicius Canale, Rocio Alvarez, and Ali Shawki of UCR; as well as colleagues at UC San Diego, Cedars-Sinai Medical Center Los Angeles, the University of Chicago, the National Institutes of Health, University Hospital Zurich in Switzerland, and McGill University in Montreal.

The study was supported by the National Institutes of Health, the Crohn's and Colitis Foundation, the Swiss National Science Foundation, and Pfizer Inc.

Story Source:

Materialsprovided byUniversity of California - Riverside. Original written by Iqbal Pittalwala.注意:内容可能被编辑风格d length.


Journal Reference:

  1. Ronald R. Marchelletta, Moorthy Krishnan, Marianne R. Spalinger, Taylaur W. Placone, Rocio Alvarez, Anica Sayoc-Becerra, Vinicius Canale, Ali Shawki, Young Su Park, Lucas H.P. Bernts, Stephen Myers, Michel L. Tremblay, Kim E. Barrett, Evan Krystofiak, Bechara Kachar, Dermot P.B. McGovern, Christopher R. Weber, Elaine M. Hanson, Lars Eckmann, Declan F. McCole.T cell protein tyrosine phosphatase protects intestinal barrier function by restricting epithelial tight junction remodeling.Journal of Clinical Investigation, Sept. 1, 2021; DOI:10.1172/JCI138230

Cite This Page:

University of California - Riverside. "Novel mechanism links genetic defect in IBD patients to gut leakiness: Study in mice and human tissue is the first to show how a disease mutation weakens barrier properties of epithelial cells lining the gut." ScienceDaily. ScienceDaily, 2 September 2021. .
University of California - Riverside. (2021, September 2). Novel mechanism links genetic defect in IBD patients to gut leakiness: Study in mice and human tissue is the first to show how a disease mutation weakens barrier properties of epithelial cells lining the gut.ScienceDaily. Retrieved July 21, 2023 from www.koonmotors.com/releases/2021/09/210902174812.htm
University of California - Riverside. "Novel mechanism links genetic defect in IBD patients to gut leakiness: Study in mice and human tissue is the first to show how a disease mutation weakens barrier properties of epithelial cells lining the gut." ScienceDaily. www.koonmotors.com/releases/2021/09/210902174812.htm (accessed July 21, 2023).

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