Perp Deficiency Induces Defective Negative Selection and Autoimmune Arthritis in Aged Mice.

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• Thymic negative selection is essential for self-tolerance by removing autoreactive T-cells.
• The PERP protein is involved in apoptosis and tumor suppression, but its role in T-cell development is unclear.
• PERP expression is regulated by p53 and often downregulated in cancers.

Purpose of the Study:

• To investigate the specific role of the PERP gene in thymic T-cell development and self-tolerance.
• To analyze the consequences of conditional Perp knockout on T-cell populations and autoimmunity.

Main Methods:

• Conditional knockout mouse models were generated to study Perp's function.
• Ex vivo and in vivo analyses were performed on thymocyte and peripheral T-cell populations.
• Flow cytometry and assessment of autoimmune phenotypes were utilized.

Main Results:

• Conditional Perp knockout mice showed defects in thymic T-cell development, with accumulation of CD4SP thymocytes.
• Perp regulates the survival of thymic T-cell subsets during negative selection, especially CD4SP T-cells.
• These mice exhibited an expansion of Helios+ CD4SP thymocytes and peripheral accumulation of activated CD4+ T-cells.
• Middle-aged Perp knockout mice developed T cell-mediated autoimmune arthritis.

Conclusions:

• Conditional deletion of Perp impairs thymic negative selection, leading to a breakdown of self-tolerance.
• Perp deficiency results in heightened susceptibility to age-related autoimmunity.
• PERP is a critical regulator of T-cell homeostasis and prevention of autoimmune diseases.