Nod1 Limits Colitis-Associated Tumorigenesis by Regulating IFN-γ Production

Area of Science:

• Immunology
• Gastroenterology
• Oncology

Background:

• Chronic intestinal inflammation is a significant risk factor for colorectal cancer.
• Nod1, a bacterial sensor, has shown protective effects against chemically induced colitis and tumorigenesis in mice, but its mechanism remains unclear.

Purpose of the Study:

• To elucidate the mechanism by which Nod1 mediates protection against inflammation-induced intestinal tumorigenesis.
• To investigate the role of Nod1 expression in the hematopoietic cell compartment.

Main Methods:

• Utilized dextran sulfate sodium (DSS)-induced acute inflammation model in mice.
• Assessed T cell IFN-γ production in vivo and in vitro.
• Administered Nod1 ligand KF1B to anti-CD3-activated T cells.
• Performed adoptive transfer of Nod1(-/-), IFNγ(-/-), and wild-type T cells into T cell-deficient mice.

Main Results:

• Nod1 expression in hematopoietic cells is critical for limiting intestinal tumorigenesis.
• Nod1-deficient T cells showed impaired IFN-γ production during DSS-induced inflammation.
• Nod1 ligand KF1B enhanced IFN-γ responses in activated T cells.
• Absence of IFN-γ signaling or Nod1 in transferred T cells led to increased tumorigenesis.

Conclusions:

• Nod1 suppresses colitis-associated tumorigenesis via a T cell-mediated mechanism.
• IFN-γ production by T cells is a key pathway for Nod1-mediated tumor suppression.
• Highlights a novel role for the innate immune receptor Nod1 in cancer prevention.