T cell-derived interferon-γ programs stem cell death in immune-mediated intestinal damage.

Area of Science:

• Immunology
• Gastroenterology
• Stem Cell Biology

Background:

• Intestinal stem cells (ISCs) are crucial for maintaining gut epithelial health.
• The impact of immune-mediated damage on ISCs and their niche is not well understood.

Purpose of the Study:

• To investigate how T cell-mediated immunopathology affects intestinal stem cells.
• To identify the mechanisms by which T cells damage ISCs and their niche.

Main Methods:

• Allogeneic bone marrow transplantation (BMT) models in mice.
• Ex vivo epithelial cultures with human and murine organoids.
• Interferon-gamma (IFNγ) and JAK/STAT signaling pathway analysis.
• Genetic modification of T cells, IFNγ, and IFNγ receptors.

Main Results:

• T cell infiltration in the gut after BMT primarily targets the crypt region, damaging ISCs.
• Activated T cells induce ISC depletion and organoid death via interferon-gamma (IFNγ).
• IFNγ triggers JAK1/STAT1-dependent apoptosis in ISCs, independent of Paneth cells.
• Blocking IFNγ, IFNγ receptor, or JAK/STAT signaling protects ISCs from T cell-mediated damage.

Conclusions:

• Dysregulated T cell activation and IFNγ production are key drivers of ISC injury.
• Targeting JAK/STAT signaling in ISCs can prevent T cell-mediated stem cell damage.
• Understanding these mechanisms is vital for treating intestinal inflammatory diseases.