GSE200821
Pharmacological inhibition of G9a ameliorates pulmonary vascular remodeling in PAH
Background:Pulmonary arterial hypertension (PAH) is a severe condition characterized by progressive vascular remodeling of small pulmonary arteries (PAs) causing sustained elevation of PA pressure, right ventricular failure and death. Similar to cancer cells, PA smooth muscle cells (PASMCs), which play a key role in pulmonary vascular remodeling, have adopted multiple mechanisms to sustain their survival and proliferation in the presence of stress. The histone methyltransferase G9a has been shown to exert oncogenic effects and to serve as a buffer against an exaggerated transcriptional response. Therefore, we hypothesized that G9a up-regulation in PAH plays a pivotal role in pulmonary vascular remodeling by maintaining the abnormal phenotype of PAH-PASMCs. Methods: G9alevels were measured in PAs and isolated PASMCs of PAH patients and animal models. Selective G9a pharmacological inhibitors were used in human PAH-PASMCs and in rodent PAH models (i.e.Fawn-Hooded rats and Sugen/Hypoxia-exposed mice). Results: We present evidence of increased expression of G9a in PASMCs from PAH patients as well as in remodeled PAs from animal models. We found that pharmacological inhibition of G9a activity using BIX01294 and UNC0642significantly reduces the prosurvival and proproliferative potentials of cultured PAH-PASMCs. Using RNA sequencing, further exploration revealed that G9a promotes extracellular matrix production and affords protection against the negative effects of an overactive stress response. Finally, we found that therapeutic treatment with BIX01294 reduced pulmonary vascular remodeling and lowered mean PA pressure in Fawn-Hooded rats. Treatment of Sugen/hypoxia-challenged mice with BIX01294 also improved pulmonary hemodynamics and right ventricular function. Conclusions:These findings suggest that G9a inhibition may represent a new therapeutic approach in PAH. Overall design: RNASeq of 3 treated and 5 Vehicle cell lines from PAH samples