Activation of Lung p53 by Nutlin-3a Prevents and Reverses Experimental Pulmonary Hypertension

• Published in: Circulation (New York, N.Y.) N.Y.), 2013-04, Vol.127 (16), p.1664-1676
• Main Authors: MOURARET, Nathalie, MARCOS, Elisabeth, AMSELLEM, Valérie, ADNOT, Serge, ABID, Shariq, GARY-BOBO, Guillaume, SAKER, Mirna, HOUSSAINI, Amal, DUBOIS-RANDE, Jean-Luc, BOYER, Laurent, BOCZKOWSKI, Jorge, DERUMEAUX, Genevieve
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis - drug effects; Arterial hypertension. Arterial hypotension; Biochemistry, Molecular Biology; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Cells, Cultured - drug effects; Cellular Senescence - drug effects; Cyclin-Dependent Kinase Inhibitor p21 - deficiency; Cyclin-Dependent Kinase Inhibitor p21 - physiology; Diseases of the peripheral vessels. Diseases of the vena cava. Miscellaneous; Drug Evaluation, Preclinical; Endothelial Cells - drug effects; Gene Expression Regulation - drug effects; Genes, p53; Humans; Hypertension, Pulmonary - chemically induced; Hypertension, Pulmonary - diagnostic imaging; Hypertension, Pulmonary - drug therapy; Hypertension, Pulmonary - etiology; Hypertension, Pulmonary - pathology; Hypertension, Pulmonary - prevention & control; Hypoxia - complications; Imidazoles - pharmacology; Imidazoles - therapeutic use; Indoles - toxicity; Life Sciences; Male; Medical sciences; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Phosphorylation - drug effects; Piperazines - pharmacology; Piperazines - therapeutic use; Pneumology; Protein Processing, Post-Translational - drug effects; Protein Stability - drug effects; Pulmonary Artery - cytology; Pulmonary Artery - pathology; Pulmonary hypertension. Acute cor pulmonale. Pulmonary embolism. Pulmonary vascular diseases; Pyrroles - toxicity; Serotonin Plasma Membrane Transport Proteins - biosynthesis; Serotonin Plasma Membrane Transport Proteins - genetics; Serotonin Plasma Membrane Transport Proteins - physiology; Single-Blind Method; Tumor Suppressor Protein p53 - agonists; Tumor Suppressor Protein p53 - antagonists & inhibitors; Tumor Suppressor Protein p53 - deficiency; Ultrasonography
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circulationaha.113.002434

Induction of cellular senescence through activation of the p53 tumor suppressor protein is a new option for treating proliferative disorders. Nutlins prevent the ubiquitin ligase MDM2 (murine double minute 2), a negative p53 regulator, from interacting with p53. We hypothesized that cell senescence induced by Nutlin-3a exerted therapeutic effects in pulmonary hypertension (PH) by limiting the proliferation of pulmonary artery smooth muscle cells (PA-SMCs). Nutlin-3a treatment of cultured human PA-SMCs resulted in cell growth arrest with the induction of senescence but not apoptosis; increased phosphorylated p53 protein levels; and expression of p53 target genes including p21, Bax, BTG2, and MDM2. Daily intraperitoneal Nutlin-3a treatment for 3 weeks dose-dependently reduced PH, right ventricular hypertrophy, and distal pulmonary artery muscularization in mice exposed to chronic hypoxia or SU5416/hypoxia. Nutlin-3a treatment also partially reversed PH in chronically hypoxic or transgenic mice overexpressing the serotonin-transporter in SMCs (SM22-5HTT+ mice). In these mouse models of PH, Nutlin-3a markedly increased senescent p21-stained PA-SMCs; lung p53, p21, and MDM2 protein levels; and p21, Bax, PUMA, BTG2, and MDM2 mRNA levels; but induced only minor changes in control mice without PH. Marked MDM2 immunostaining was seen in both mouse and human remodeled pulmonary vessels, supporting the use of Nutlins as a PH-targeted therapy. PH prevention or reversal by Nutlin-3a required lung p53 stabilization and increased p21 expression, as indicated by the absence of Nutlin-3a effects in hypoxia-exposed p53(-/-) and p21(-/-) mice. Nutlin-3a may hold promise as a prosenescence treatment targeting PA-SMCs in PH.