Environmental Aromatic Amine Induces Pulmonary Arterial Hypertension Associated With Estrogen Signaling and Serpine1

4,4′-Diaminodiphenylmethane (DAPM) is an aromatic amine used in the industrial synthesis of polyurethane. In rats, acute DAPM exposure induces biliary epithelial cell injury in the liver, but subchronic exposure promotes a female-specific pulmonary arterial hypertension (PAH). PAH in humans is four times more prevalent in women than men. To shed light on mechanisms explaining the female selectivity of PAH in humans, we examined molecular pathways underlying DAPM-induced PAH in female rats. Intersections between DAPM-mediated hepatic injury and DAPM-induced PAH were also interrogated. Intact compared to ovariectomized female rats were gavaged once weekly for 12 weeks with DAPM or vehicle. Morphometric analysis in lung sections was used to quantify PAH pathology. mRNA from liver were assessed for DAPM-induced alterations in genes associated with aryl hydrocarbon receptor, estrogen response, and endothelin-1 signaling. mRNA from pulmonary arteries were subjected to transcript profiling, and pathways associated with differentially expressed genes were mapped. First, DAPM-induced PAH was exacerbated by ovariectomy. Although DAPM-mediated liver injury per se was not correlated with its induction of PAH, increases in levels of the potent vasoconstrictor endothelin-1 were exacerbated by ovariectomy and were correlated with increased expression of Edn1 in the liver. In pulmonary arteries, transcript profiling revealed that DAPM and ovariectomy interacted to dysregulate estrogen receptor, VEGF, PI3K/AKT, endothelin-1, glucocorticoid receptor, IL-17A, and idiopathic pulmonary fibrosis signaling. One of the most dysregulated genes associated with both DAPM and estrogen status was Serpine1.