Targeting Setdb1 in T cells induces transplant tolerance without compromising antitumor immunity

Area of Science:

• Immunology
• Epigenetics
• Transplantation Biology

Background:

• Suppressing immune responses aids allograft survival but can promote tumor growth.
• A challenge exists in selectively suppressing allograft rejection while maintaining antitumor immunity.

Purpose of the Study:

• To investigate the role of Setdb1 (an H3K9 methyltransferase) in regulating immune responses for allograft survival and antitumor immunity.
• To elucidate the mechanisms by which Setdb1 influences T regulatory (Treg) cell differentiation and function.

Main Methods:

• Utilized mice deficient in Setdb1.
• Performed RNA sequencing and single-cell RNA sequencing.
• Depleted regulatory T cells to assess their role in graft acceptance.

Main Results:

• Setdb1 deficiency led to loss of allograft rejection without compromising antitumor immunity.
• Setdb1-deficient mice exhibited increased Treg cell-associated gene expression.
• Setdb1 deficiency induced a novel Treg cell population in the thymus with altered IL-1R2 and IL-18R1 expression.
• Setdb1 functions upstream of Foxp3 induction in Treg cell differentiation.

Conclusions:

• Setdb1 in T cells acts as a critical regulator of Treg cell differentiation.
• Loss of Setdb1 function in T cells dissociates allograft rejection suppression from antitumor immunity maintenance.
• Targeting Setdb1 may offer a strategy for improving transplant outcomes without increasing cancer risk.