Estrogen Metabolite 16α-Hydroxyestrone Exacerbates Bone Morphogenetic Protein Receptor Type II-Associated Pulmonary Arterial Hypertension Through MicroRNA-29-Mediated Modulation of Cellular Metabolism.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a proliferative disease of the pulmonary vasculature that preferentially affects women. Estrogens such as the metabolite 16α-hydroxyestrone (16αOHE) may contribute to PAH pathogenesis, and alterations in cellular energy metabolism associate with PAH. We hypothesized that 16αOHE promotes heritable PAH (HPAH) via microRNA-29 (miR-29) family upregulation and that antagonism of miR-29 would attenuate pulmonary hypertension in transgenic mouse models of Bmpr2 mutation. METHODS AND RESULTS: MicroRNA array profiling of human lung tissue found elevation of microRNAs associated with energy metabolism, including the miR-29 family, among HPAH patients. miR-29 expression was 2-fold higher in Bmpr2 mutant mice lungs at baseline compared with controls and 4 to 8-fold higher in Bmpr2 mice exposed to 16αOHE 1.25 µg/h for 4 weeks. Blot analyses of Bmpr2 mouse lung protein showed significant reductions in peroxisome proliferator-activated receptor-γ and CD36 in those mice exposed to 16αOHE and protein derived from HPAH lungs compared with controls. Bmpr2 mice treated with anti-miR-29 (20-mg/kg injections for 6 weeks) had improvements in hemodynamic profile, histology, and markers of dysregulated energy metabolism compared with controls. Pulmonary artery smooth muscle cells derived from Bmpr2 murine lungs demonstrated mitochondrial abnormalities, which improved with anti-miR-29 transfection in vitro; endothelial-like cells derived from HPAH patient induced pluripotent stem cell lines were similar and improved with anti-miR-29 treatment. CONCLUSIONS: 16αOHE promotes the development of HPAH via upregulation of miR-29, which alters molecular and functional indexes of energy metabolism. Antagonism of miR-29 improves in vivo and in vitro features of HPAH and reveals a possible novel therapeutic target.

Functional variant of CYP4A11 20-hydroxyeicosatetraenoic acid synthase is associated with essential hypertension.

BACKGROUND: The CYP4A11 arachidonic acid monooxygenase oxidizes endogenous arachidonic acid (AA) to 20-hydroxyeicosatetraenoic acid (20-HETE), a metabolite with renovascular and tubular functions. Mice with targeted disruption of Cyp4a14, a murine homologue of CYP4A11, have severe hypertension. We combined molecular and biochemical approaches to identify a functional variant of the CYP4A11 20-HETE synthase and determine its association with hypertensive status in 2 independent human populations. METHODS AND RESULTS: A thymidine-to-cytosine polymorphism at nucleotide 8590 resulted in a phenylalanine-to-serine substitution at amino acid 434. Expression of cDNA with serine 434 resulted in a protein with a significantly reduced AA and lauric acid metabolizing activity. In a population of 512 whites from Tennessee, the age, body mass index, and gender-adjusted OR of having hypertension attributable to the 8590C variant was 2.31 (95% CI 1.41 to 3.78) compared with the reference 8590TT genotype. In subjects from the Framingham Heart Study, the adjusted ORs of hypertension associated with the 8590C variant were 1.23 (CI 0.94 to 1.59; n=1538) in all subjects and 1.33 (CI 1.01 to 1.77; n=1331) when subjects with diabetes were excluded. No association of the variant with hypertension was detected in a population of 120 blacks. CONCLUSIONS: We identified a variant of the human CYP4A11 (T8590C) that encodes for a monooxygenase with reduced 20-HETE synthase activity. The association of the T8590C variant with hypertension supports its role as a polygenic determinant of blood pressure control in humans, and results obtained from the large population database suggest that the relevance of the variant may vary according to hypertension comorbidity.