SHARPIN controls the development of regulatory T cells

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• SHARPIN is a key component of the linear ubiquitin chain assembly complex (LUBAC).
• LUBAC regulates signaling pathways of receptors like TNFR, TLR, and antigen receptors.
• SHARPIN's role in T cells, particularly regulatory T (Treg) cells, was previously unexplored.

Purpose of the Study:

• To investigate the role of SHARPIN in T-cell receptor (TCR) signaling.
• To determine SHARPIN's function in the development and biology of regulatory T (Treg) cells.

Main Methods:

• Analysis of SHARPIN-deficient (Sharpin(cpdm/cpdm)) mice.
• Competitive bone marrow reconstitution assays.
• TCR stimulation assays on thymocytes.
• In vitro Treg cell generation and functional assays.

Main Results:

• SHARPIN-deficient mice exhibit significantly reduced Treg cell numbers.
• SHARPIN deficiency leads to impaired thymic Treg development.
• TCR stimulation in SHARPIN-deficient thymocytes shows reduced NF-κB and JNK activation.
• In vitro generation and suppressive function of mature Treg cells are not impaired by SHARPIN deficiency.

Conclusions:

• SHARPIN is essential for TCR signaling and the in vivo generation of Treg cells.
• SHARPIN's role is critical for Treg cell development, not their mature function.
• These findings highlight SHARPIN's importance in T-cell biology and immune regulation.