Inhibins regulate peripheral regulatory T cell induction through modulation of dendritic cell function.

Area of Science:

• Immunology
• Endocrinology
• Cell Biology

Background:

• Previous studies linked inhibin deficiency to impaired dendritic cell (DC) function and reduced T cell responses.
• The role of inhibins in peripheral regulatory T cell (Treg) induction remained unclear.

Purpose of the Study:

• To investigate the role of inhibins in the induction of peripheral regulatory T cells (Tregs) both in vitro and in vivo.
• To determine if inhibin deficiency impacts Treg development and immune tolerance.

Main Methods:

• Utilized inhibin-deficient (Inhα-/-) and wild-type (Inhα+/+) mice.
• Analyzed Treg percentages in colonic lamina propria and mesenteric lymph nodes.
• Assessed PD-L1 expression on dendritic cells (DCs).
• Performed in vitro Treg induction assays with bone marrow-derived and ex vivo purified DCs.
• Conducted in vivo DC targeting experiments using anti-DEC205-ovalbumin (OVA) and adoptively transferred OVA-specific T cells.

Main Results:

• Inhibin-deficient mice exhibited a higher percentage of peripherally induced Tregs.
• This increase correlated with elevated PD-L1 expression on CD103+ and CD8α+ DCs in Inhα-/- mice.
• Inhibin-deficient DCs demonstrated enhanced capacity to induce Tregs in vitro.
• In vivo DC targeting confirmed enhanced Treg conversion in Inhα-/- mice.

Conclusions:

• Inhibins are identified as critical regulators of peripheral T cell tolerance.
• The absence of inhibins promotes Treg induction, potentially through enhanced DC function and PD-L1 expression.
• These findings reveal a novel mechanism by which inhibins modulate immune responses and maintain self-tolerance.