Inhibins tune the thymocyte selection process by regulating thymic stromal cell differentiation

Area of Science:

• Immunology
• Developmental Biology
• Endocrinology

Background:

• Inhibins and Activins, TGF-β superfamily members, regulate cell differentiation and were initially identified as hormones.
• Emerging evidence highlights their crucial roles in immune system regulation.
• Previous studies showed Inhibins regulate thymocyte differentiation in murine thymus.

Purpose of the Study:

• To investigate the role of Inhibins in thymic stromal cell differentiation and function.
• To understand how Inhibins affect thymic microenvironment and T cell selection.

Main Methods:

• Analysis of thymic conventional dendritic cells (cDCs) in the absence of Inhibins.
• Assessment of thymic epithelial cell (TEC) ratios (cortical vs. medullary).
• Evaluation of thymocyte selection, including CD4SP thymocyte development and regulatory T cell generation.

Main Results:

• Absence of Inhibins led to reduced MHC Class II and CD86 on cDCs.
• Inhibin deficiency altered the cTEC/mTEC ratio, favoring mTEC differentiation.
• Thymocyte selection was impaired, with decreased CD4SP thymocytes and increased natural regulatory T cells.

Conclusions:

• Inhibins are critical regulators of thymic stromal cell function, impacting cDC maturation and TEC differentiation.
• Inhibins modulate T cell selection by coordinating thymocyte and stromal cell development.
• These findings reveal a novel mechanism by which Inhibins fine-tune immune responses within the thymus.