p53 isoforms regulate aging- and tumor-associated replicative senescence in T lymphocytes

Area of Science:

• Immunology
• Cell Biology
• Aging Research

Background:

• Cellular senescence drives aging and tissue dysfunction.
• p53 isoform switching is implicated in senescence and cancer.
• The roles of p53 isoforms in T lymphocyte senescence in vivo are not fully understood.

Purpose of the Study:

• To investigate the role of p53 isoforms (Δ133p53 and p53β) in regulating proliferation and senescence in human T lymphocytes.
• To explore the potential of targeting these isoforms for therapeutic interventions in age-related and immune disorders.

Main Methods:

• Analysis of peripheral blood and tumor-associated CD8+ T lymphocytes from healthy donors and cancer patients.
• Induction of replicative senescence in cultured CD8+ T lymphocytes.
• Manipulation of Δ133p53 and p53β expression using knockdown and reconstitution techniques.
• Assessment of cell proliferation, replicative lifespan, and senescence markers (CD28, CD57).

Main Results:

• Senescent CD8+ T lymphocytes (CD28-CD57+) accumulate with age and in tumors, showing decreased Δ133p53 and increased p53β.
• Replicative senescence in cultured T cells involves loss of CD28 and Δ133p53.
• Restoring Δ133p53 or CD28 in senescent cells revived proliferation and extended lifespan.
• Δ133p53 knockdown or p53β overexpression induced senescence and inhibited proliferation in healthy T cells.

Conclusions:

• Δ133p53 and p53β are key physiological regulators of proliferation and senescence in human T lymphocytes in vivo.
• Restoring Δ133p53 shows promise for treating immunosenescence and related diseases.
• This research opens new therapeutic avenues for aging, cancer, autoimmune diseases, and HIV infection.