Endothelial-derived FGF2 contributes to the progression of pulmonary hypertension in humans and rodents
Mohamed Izikki, … , Bernadette Raffestin, Saadia Eddahibi
Mohamed Izikki, … , Bernadette Raffestin, Saadia Eddahibi
Published February 9, 2009
Citation Information: J Clin Invest. 2009;119(3):512-523. https://doi.org/10.1172/JCI35070.
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Research Article Pulmonology

Endothelial-derived FGF2 contributes to the progression of pulmonary hypertension in humans and rodents

Abstract

Pulmonary hypertension (PH) is a progressive, lethal lung disease characterized by pulmonary artery SMC (PA-SMC) hyperplasia leading to right-sided heart failure. Molecular events originating in pulmonary ECs (P-ECs) may contribute to the PA-SMC hyperplasia in PH. Thus, we exposed cultured human PA-SMC to medium conditioned by P-EC from patients with idiopathic PH (IPH) or controls and found that IPH P-EC–conditioned medium increased PA-SMC proliferation more than control P-EC medium. Levels of FGF2 were increased in the medium of IPH P-ECs over controls, while there was no detectable difference in TGF-β1, PDGF-BB, or EGF levels. No difference in FGF2-induced proliferation or FGF receptor type 1 (FGFR1) mRNA levels was detected between IPH and control PA-SMCs. Knockdown of FGF2 in P-EC using siRNA reduced the PA-SMC growth-stimulating effects of IPH P-EC medium by 60% and control P-EC medium by 10%. In situ hybridization showed FGF2 overproduction predominantly in the remodeled vascular endothelium of lungs from patients with IPH. Repeated intravenous FGF2-siRNA administration abolished lung FGF2 production, both preventing and nearly reversing a rat model of PH. Similarly, pharmacological FGFR1 inhibition with SU5402 reversed established PH in the same model. Thus, endothelial FGF2 is overproduced in IPH and contributes to SMC hyperplasia in IPH, identifying FGF2 as a promising target for new treatments against PH.

Authors

Mohamed Izikki, Christophe Guignabert, Elie Fadel, Marc Humbert, Ly Tu, Patricia Zadigue, Philippe Dartevelle, Gerald Simonneau, Serge Adnot, Bernard Maitre, Bernadette Raffestin, Saadia Eddahibi

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Figure 1

FGF2 expression in cultured P-ECs, PA-SMCs, and lungs from patients with IPH.

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FGF2 expression in cultured P-ECs, PA-SMCs, and lungs from patients with...
(A) FGF2 expression by P-ECs and (B) PA-SMCs from controls (C-EC and C-SMC, respectively) and from patients with IPH (IPH-EC and IPH-SMC, respectively). Values are mean ± SEM from 5 controls and 5 patients with IPH. (C) FGF2 mRNA levels and (D) FGF2 protein levels in lung tissues from controls and patients with IPH. Values are mean ± SEM from 12 controls and 14 patients for mRNA levels and 5 controls and 5 patients for protein levels. (E–M) In situ hybridization in human pulmonary arteries from controls (E and H) and from patients with IPH (F, G, I, J) using 3′-[35S]–labeled oligonucleotide probes specific for human FGF2 or using a sense probe (K–M). Arrows indicate the localization of FGF2 mRNA in the vascular endothelium of muscular pulmonary arteries. *P < 0.05; ***P < 0.001 vs. P-ECs, PA-SMCs, or lungs from control subjects. Scale bars: 100 μm.