Disruption of PPARγ/β-catenin-mediated regulation of apelin impairs BMP-induced mouse and human pulmonary arterial EC survival

• Published in: The Journal of clinical investigation Vol. 121; no. 9; pp. 3735 - 3746
• Main Authors: Alastalo, Tero-Pekka, Li, Molong, Perez, Vinicio de Jesus, Pham, David, Sawada, Hirofumi, Wang, Jordon K, Koskenvuo, Minna, Wang, Lingli, Freeman, Bruce A, Chang, Howard Y, Rabinovitch, Marlene
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Investigation 01.09.2011
• Subjects: Adipokines; Animals; Apelin; Apoptosis - physiology; beta Catenin - genetics; beta Catenin - metabolism; Bone Morphogenetic Protein Receptors, Type II - genetics; Bone Morphogenetic Protein Receptors, Type II - metabolism; Bone Morphogenetic Proteins - metabolism; Cell Proliferation; Cell Survival; Cells, Cultured; Endothelial Cells - cytology; Endothelial Cells - physiology; Gene Expression; Humans; Intercellular Signaling Peptides and Proteins - genetics; Intercellular Signaling Peptides and Proteins - metabolism; Mice; Microarray Analysis; PPAR gamma - genetics; PPAR gamma - metabolism; Pulmonary Artery - cytology; RNA, Small Interfering - metabolism
• ISSN: 0021-9738; 1558-8238
• DOI: 10.1172/JCI43382

Reduced bone morphogenetic protein receptor 2 (BMPR2) expression in patients with pulmonary arterial hypertension (PAH) can impair pulmonary arterial EC (PAEC) function. This can adversely affect EC survival and promote SMC proliferation. We hypothesized that interventions to normalize expression of genes that are targets of BMPR2 signaling could restore PAEC function and prevent or reverse PAH. Here we have characterized, in human PAECs, a BMPR2-mediated transcriptional complex between PPARγ and β-catenin and shown that disruption of this complex impaired BMP-mediated PAEC survival. Using whole genome-wide ChIP-Chip promoter analysis and gene expression microarrays, we delineated PPARγ/β-catenin-dependent transcription of target genes including APLN, which encodes apelin. We documented reduced PAEC expression of apelin in PAH patients versus controls. In cell culture experiments, we showed that apelin-deficient PAECs were prone to apoptosis and promoted pulmonary arterial SMC (PASMC) proliferation. Conversely, we established that apelin, like BMPR2 ligands, suppressed proliferation and induced apoptosis of PASMCs. Consistent with these functions, administration of apelin reversed PAH in mice with reduced production of apelin resulting from deletion of PPARγ in ECs. Taken together, our findings suggest that apelin could be effective in treating PAH by rescuing BMPR2 and PAEC dysfunction.