HnRNP L is essential for peripheral T cell proliferation and survival

Area of Science:

• Immunology
• Molecular Biology
• Cell Biology

Background:

• Heterogeneous nuclear ribonucleoprotein L (hnRNP L) is implicated in T cell development and differentiation.
• Understanding hnRNP L's role in peripheral T cell function is essential for immune response insights.

Purpose of the Study:

• To investigate the function of hnRNP L in peripheral CD4 T cell survival and activation.
• To elucidate the impact of hnRNP L deficiency on T cell differentiation and immune response.

Main Methods:

• Generated CD4Cre x hnRNP L^Fl/Fl (KO) mice for analysis.
• Performed in vitro and in vivo studies on CD4 T cell differentiation, proliferation, and apoptosis.
• Analyzed TCR-mediated signaling pathways and immune responses.

Main Results:

• hnRNP L deficient T cells exhibit reduced peripheral numbers, impaired T helper subset differentiation, decreased proliferation, and increased apoptosis.
• KO CD4 T cells failed to differentiate into T follicular helper (Tfh) cells and support germinal center B cell formation.
• hnRNP L deficiency prevented Bcl-XL upregulation and increased susceptibility to apoptosis, reversible with pan-caspase inhibition.

Conclusions:

• hnRNP L plays a critical pro-survival role in activated T cells.
• Alternative splicing of anti-apoptotic factors is a key mechanism regulated by hnRNP L for T cell survival.