This is inline with other studies which found that GJA4 gene expression was reducedin the right ventricular tissue of pulmonary artery banded mice27 and also in PAECs from PAH patients.14 In the current study, hypoxia downregulated protein expression of Cx37 and Cx40 inrPASMCs and increased protein expression of Cx37 and Cx43 in rPAFs. This evidence concerns the gene GJA4 and pulmonary arterial hypertension.