Androgen receptors in thymic epithelium modulate thymus size and thymocyte development

Area of Science:

• Immunology
• Endocrinology
• Developmental Biology

Background:

• Androgen receptor (AR) mediates androgen effects, including thymus size regulation in rodents.
• Previous studies suggested AR expression in both lymphoid and non-lymphoid thymic cells, but specific roles were unclear.

Purpose of the Study:

• To investigate the cellular localization and functional significance of the androgen receptor (AR) in the thymus.
• To determine whether AR expression in thymic epithelial cells influences thymocyte development and androgen responsiveness.

Main Methods:

• Immunohistochemical analysis and hormone binding assays to detect AR in thymic epithelial cells.
• Generation of chimeric mice via bone marrow transplantation to isolate AR expression to lymphoid or epithelial compartments.
• Phenotypic analysis of lymphocytes and thymus size assessment in chimeric mice.

Main Results:

• AR was confirmed in thymic epithelial cells.
• Chimeric mice with AR-expressing epithelium and AR-null thymocytes exhibited normal thymus size and androgen response.
• Chimeric mice with AR-null epithelium and AR-expressing thymocytes showed thymus enlargement and androgen insensitivity.
• Loss of AR in thymic epithelium abrogated normal androgenic modulation of lymphocyte populations.

Conclusions:

• Androgen receptor (AR) expression in thymic epithelial cells is essential for regulating thymus size and mediating androgenic effects on thymocyte development.
• Thymic epithelial cells are critical targets for androgens in modulating immune cell maturation.