Dysfunction of the MDM2/p53 axis is linked to premature aging
Davor Lessel, Danyi Wu, Carlos Trujillo, Thomas Ramezani, Ivana Lessel, Mohammad K. Alwasiyah, Bidisha Saha, Fuki M. Hisama, Katrin Rading, Ingrid Goebel, Petra Schütz, Günter Speit, Josef Högel, Holger Thiele, Gudrun Nürnberg, Peter Nürnberg, Matthias Hammerschmidt, Yan Zhu, David R. Tong, Chen Katz, George M. Martin, Junko Oshima, Carol Prives, Christian Kubisch
Davor Lessel, Danyi Wu, Carlos Trujillo, Thomas Ramezani, Ivana Lessel, Mohammad K. Alwasiyah, Bidisha Saha, Fuki M. Hisama, Katrin Rading, Ingrid Goebel, Petra Schütz, Günter Speit, Josef Högel, Holger Thiele, Gudrun Nürnberg, Peter Nürnberg, Matthias Hammerschmidt, Yan Zhu, David R. Tong, Chen Katz, George M. Martin, Junko Oshima, Carol Prives, Christian Kubisch
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Concise Communication Aging Genetics

Dysfunction of the MDM2/p53 axis is linked to premature aging

Abstract

The tumor suppressor p53, a master regulator of the cellular response to stress, is tightly regulated by the E3 ubiquitin ligase MDM2 via an autoregulatory feedback loop. In addition to its well-established role in tumorigenesis, p53 has also been associated with aging in mice. Several mouse models with aberrantly increased p53 activity display signs of premature aging. However, the relationship between dysfunction of the MDM2/p53 axis and human aging remains elusive. Here, we have identified an antiterminating homozygous germline mutation in MDM2 in a patient affected by a segmental progeroid syndrome. We show that this mutation abrogates MDM2 activity, thereby resulting in enhanced levels and stability of p53. Analysis of the patient’s primary cells, genome-edited cells, and in vitro and in vivo analyses confirmed the MDM2 mutation’s aberrant regulation of p53 activity. Functional data from a zebrafish model further demonstrated that mutant Mdm2 was unable to rescue a p53-induced apoptotic phenotype. Altogether, our findings indicate that mutant MDM2 is a likely driver of the observed segmental form of progeria.

Authors

Davor Lessel, Danyi Wu, Carlos Trujillo, Thomas Ramezani, Ivana Lessel, Mohammad K. Alwasiyah, Bidisha Saha, Fuki M. Hisama, Katrin Rading, Ingrid Goebel, Petra Schütz, Günter Speit, Josef Högel, Holger Thiele, Gudrun Nürnberg, Peter Nürnberg, Matthias Hammerschmidt, Yan Zhu, David R. Tong, Chen Katz, George M. Martin, Junko Oshima, Carol Prives, Christian Kubisch

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Figure 3

The antiterminating mutation results in abnormal p53 functional responses.

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The antiterminating mutation results in abnormal p53 functional response...
(A) MDM2 and p53 could be coimmunoprecipitated. Proteins were harvested from control and IV:7 LCLs and detected after coimmunoprecipitation with anti-MDM2 antibody (H-221) and subsequent immunoblotting. All samples were run on the same gel but were noncontiguous. (B) Control 1 and IV:7 fibroblasts were treated for 24 hours with DMSO, Nutlin-3 and daunorubicin. Cells were harvested and used for protein or mRNA analysis. Cells were lysed and used for immunoblotting with the indicated antibodies. Quantitative reverse transcription PCR (qRT-PCR) analysis revealed relative mRNA levels of p53 target genes after treatment. Bar graph is representative of 3 independent experiments and shows no statistical significance. (C) Time course of p-p53, p53, and MDM2 protein levels after treatment with MMC, APH, and daunorubicin. Protein levels of p-p53 (Ser15), p53, and MDM2 in fibroblasts treated with MMC (40 ng/ml), APH (0.3 μM), or daunorubicin (0.1 μM). Fibroblasts from control 1 (lanes 1–4) and IV:7 (lanes 5–8) were treated for 24 hours with the indicated stressors. Cells were harvested either right after treatment (lanes 1 and 5), or were further cultured for 4 (lanes 2 and 6), 8 (lanes 3 and 7), or 24 hours (lanes 4 and 8) in stress-free medium. Cell lysates were used for immunoblotting with p-p53 (Ser15); p53 (AF1355); MDM2 (N20); and anti-actin. (D) qRT-PCR analysis showing relative mRNA levels of p53 target genes after treatment with DMSO or Nutlin-3 for 24 hours in WT/WT, WT/MUT, and MUT/MUT U2OS genome-edited cells. Bar graph is representative of 3 independent experiments and shows no statistical significance for Nutlin-3–treated p21 WT/MUT and MUT/MUT cell lines as compared with WT/WT cell lines.