Disruption of PPARγ/β-catenin–mediated regulation of apelin impairs BMP-induced mouse and human pulmonary arterial EC survival
Tero-Pekka Alastalo, … , Howard Y. Chang, Marlene Rabinovitch
Tero-Pekka Alastalo, … , Howard Y. Chang, Marlene Rabinovitch
Published August 8, 2011
Citation Information: J Clin Invest. 2011;121(9):3735-3746. https://doi.org/10.1172/JCI43382.
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Research Article Pulmonology

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

Abstract

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.

Authors

Tero-Pekka Alastalo, Molong Li, Vinicio de Jesus Perez, David Pham, Hirofumi Sawada, Jordon K. Wang, Minna Koskenvuo, Lingli Wang, Bruce A. Freeman, Howard Y. Chang, Marlene Rabinovitch

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Figure 8

Apelin deficiency in PAECs contributes to PASMC proliferation.

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Apelin deficiency in PAECs contributes to PASMC proliferation. (A) PAEC-...
(A) PAEC-conditioned media (CM) after treatment with control or apelin siRNA (see Methods) was used to stimulate PASMCs for 72 hours, and proliferation was analyzed by cell counts and MTT assay. 5% FBS was used as a positive control, and starvation media alone was used as a baseline control. (B) Effect of 100 nM apelin on 20 ng/ml PDGFB–mediated PASMC proliferation, analyzed by cell counts and MTT assays at 72 hours. (C) Caspase 3/7 assay to measure apoptosis in PASMCs exposed to 10 or 100 nM apelin under SF conditions for 48 hours. Bars represent mean ± SEM from 3 separate experiments with 6 replicates per condition. *P < 0.05, **P < 0.01, ***P < 0.001 vs. respective baseline control, 1-way ANOVA with Bonferroni multiple comparison test.