Cell Cycle Sensing Shapes Human T Cell Fate and Exhaustion Programs.

Area of Science:

• Immunology
• Cell Biology
• Cancer Research

Background:

• Cell cycle (CC) dynamics are integral to T cell functions including activation, differentiation, and exhaustion.
• Understanding the interplay between CC checkpoints and T cell fate decisions is crucial for both development and disease.
• The precise relationship between CC sensing and T cell differentiation programs remains largely unexplored.

Purpose of the Study:

• To investigate the crosstalk between cell cycle progression, receptor signaling, and T cell differentiation.
• To elucidate the role of CC dynamics in T cell exhaustion and dysfunction.
• To determine how aberrant CC progression impacts T cell states in various settings.

Main Methods:

• Utilized high-throughput single-cell mass cytometry to simultaneously measure CC, signaling, and T cell states.
• Employed pharmacological inhibitors to modulate CC progression and receptor signaling.
• Investigated T cell exhaustion using tonic signaling Chimeric Antigen Receptor (CAR) models.

Main Results:

• Early G1/S phase CC programs were found to interact with receptor signaling, influencing T cell fate decisions.
• Aberrant S-G2 phase CC arrest signatures were identified as downstream events in tonic CAR signaling.
• These CC abnormalities correlate with CD8 T-lymphocyte dysfunction in vitro, in situ, and in vivo, particularly in human cancers.

Conclusions:

• Cell cycle progression is a critical regulator of T cell differentiation and function.
• Dysregulated cell cycle dynamics, specifically S-G2 arrest, contribute to T cell exhaustion and dysfunction.
• Targeting cell cycle pathways may offer novel strategies for enhancing T cell-mediated immunity in cancer.