p53 isoforms regulate aging- and tumor-associated replicative senescence in T lymphocytes
Abdul M. Mondal, … , David P. Lane, Curtis C. Harris
Abdul M. Mondal, … , David P. Lane, Curtis C. Harris
Published November 15, 2013
Citation Information: J Clin Invest. 2013;123(12):5247-5257. https://doi.org/10.1172/JCI70355.
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Research Article Aging

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

Abstract

Cellular senescence contributes to aging and decline in tissue function. p53 isoform switching regulates replicative senescence in cultured fibroblasts and is associated with tumor progression. Here, we found that the endogenous p53 isoforms Δ133p53 and p53β are physiological regulators of proliferation and senescence in human T lymphocytes in vivo. Peripheral blood CD8+ T lymphocytes collected from healthy donors displayed an age-dependent accumulation of senescent cells (CD28–CD57+) with decreased Δ133p53 and increased p53β expression. Human lung tumor-associated CD8+ T lymphocytes also harbored senescent cells. Cultured CD8+ blood T lymphocytes underwent replicative senescence that was associated with loss of CD28 and Δ133p53 protein. In poorly proliferative, Δ133p53-low CD8+CD28– cells, reconstituted expression of either Δ133p53 or CD28 upregulated endogenous expression of each other, which restored cell proliferation, extended replicative lifespan and rescued senescence phenotypes. Conversely, Δ133p53 knockdown or p53β overexpression in CD8+CD28+ cells inhibited cell proliferation and induced senescence. This study establishes a role for Δ133p53 and p53β in regulation of cellular proliferation and senescence in vivo. Furthermore, Δ133p53-induced restoration of cellular replicative potential may lead to a new therapeutic paradigm for treating immunosenescence disorders, including those associated with aging, cancer, autoimmune diseases, and HIV infection.

Authors

Abdul M. Mondal, Izumi Horikawa, Sharon R. Pine, Kaori Fujita, Katherine M. Morgan, Elsa Vera, Sharlyn J. Mazur, Ettore Appella, Borivoj Vojtesek, Maria A. Blasco, David P. Lane, Curtis C. Harris

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Figure 2

Diminished Δ133p53 and elevated p53β in the CD28–CD57+ subset of CD8+ T lymphocytes in vivo.

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Diminished Δ133p53 and elevated p53β in the CD28–CD57+ subset of CD8+ T ...
(A) Immunoblot of CD28/CD57 quadrants of blood CD8+ T lymphocytes showing Δ133p53 and p53β proteins (donors 1–6). The CD28+CD57+ and CD28–CD57– subsets from donors 3–6 did not give enough amounts of protein because of low cell counts. p53β bands are denoted by thin lines at right of lanes and arrowheads. Lanes were run on the same gel but were noncontiguous (black lines). Densitometric values (normalized to β-actin, expressed relative to the CD28+CD57– subset) are shown below. (B) Quantitative data summary of Δ133p53 and p53β protein expression (donors 1–6). (C–E) Quantitative RT-PCR analysis for p53β (C), SRSF3 (D), and Δ133p53 (E) (donors 1–6). B2M was used for normalization. (F) Immunoblot of bafilomycin A1–treated (Baf A1; 100 nM for 6 hours) CD28+CD57– and CD28–CD57+ subsets of blood CD8+ T lymphocytes (donors 34 and 35). Δ133p53, p53FL (detected by DO-1 antibody), p62, and LC3B proteins were examined. Inhibition of autophagy was confirmed by increased amounts of p62 and LC3B-II. Densitometric values (expressed relative to untreated cells) are shown below. (G) Quantitative data summary of Δ133p53 and p53β protein expression in the CD28+CD57– and CD28–CD57+ subsets of tumor-associated CD8+ T lymphocytes (tumors 1–3; see Supplemental Figure 9A). (H–L) Quantitative RT-PCR analysis for IL6 (H), IL8 (I), p53β (J), SRSF3 (K), and Δ133p53 (L) (tumors 5–7). B2M was used for normalization. Data are mean ± SD (B–E and G–L). *P < 0.05; **P < 0.01; ***P < 0.001.