Immunology · us
How does intestinal immunity apply the brakes? Study reveals how ZBTB44 suppresses inflammatory signaling
A new study in mice offers mechanistic clues to how a protein limits the continued release of inflammatory signals by T cells. Cell data from patients with ulcerative colitis also show related changes, but whether this regulatory pathway can be translated into treatment remains to be verified.
Immune responses in the intestine require a careful balance: signals that defend against infection can also damage the body's own tissues if they remain excessively strong. A team at the University of Texas Southwestern Medical Center in the United States found that the protein ZBTB44 limits T-cell production of interferon gamma (IFN-γ), adding a molecular regulatory clue to our understanding of how intestinal inflammation spirals out of control.
The study was published on October 12 in *Nature Immunology*. Researchers including Mahesh Kathania, Desh Raj and Venuprasad Poojary jointly advanced the work, focusing on how immune cells control IFN-γ production. This signal normally participates in responses against infection, but excessive amounts may worsen intestinal inflammation; it also provides an avenue for studying inflammatory bowel disease.
After deletion of the Zbtb44 gene, mice developed spontaneous colitis, and IFN-γ expression in T cells increased. The summary of dataset GSE294267 from the same study, listed in OmicsDI, also records rectal prolapse in the mice. More crucially, inflammation was substantially reduced when mice lacking ZBTB44 also lacked IFN-γ, supporting this immune signal's role as an important driver of disease in this model.
The team further investigated how this “brake” works. After undergoing a protein modification called SUMOylation, ZBTB44 can interact with the transcription factor T-bet. T-bet normally helps activate the IFN-γ gene; this interaction allows ZBTB44 to bind to regulatory regions of the gene, including its promoter and enhancers, reducing gene activity and limiting continued IFN-γ production.
Human data provide another layer of clues while also leaving questions about interpretation. According to descriptions from the university and its release on Newswise, the team reanalyzed single-cell gene expression data from colon biopsies of 12 patients with ulcerative colitis and 9 healthy controls, finding higher ZBTB44 expression in several types of immune cells in the patients. The researchers believe this may reflect a protective response by the body to persistent inflammation; this association alone cannot establish whether it changes the course of patients' disease.
From gene deletion experiments in mice to differences in expression in patients' cells, the study outlines the regulatory relationship among ZBTB44, T-bet and IFN-γ. However, the consequences of congenital absence of a gene cannot be directly equated with the effects of using drugs to modulate this pathway. The team explicitly positions the research as preclinical work: how to intervene, whether intervention can improve intestinal inflammation in humans, and its safety all require answers from further research.