Metabolic reprogramming is considered important in the pathogenesis of the occlusive vasculopathy observed in pulmonary hypertension (PH). However, the mechanisms that link reprogrammed metabolism to aberrant expression of genes, which modulate functional phenotypes of cells in PH, remain enigmatic. Herein, we demonstrate that, in mice, hypoxia-induced PH was prevented by glucose-6-phosphate dehydrogenase deficiency (G6PDDef), and further show that established severe PH in Cyp2c44−/− mice was attenuated by knockdown with G6PD shRNA or by G6PD inhibition with an inhibitor (N-ethyl-N′-[(3β,5α)-17-oxoandrostan-3-yl]urea, NEOU). Mechanistically, G6PDDef, knockdown and inhibition in lungs: 1) reduced hypoxia-induced changes in cytoplasmic and mitochondrial metabolism, 2) increased expression of Tet methylcytosine dioxygenase 2 ( Tet2) gene, and 3) upregulated expression of the coding genes and long noncoding (lnc) RNA Pint, which inhibits cell growth, by hypomethylating the promoter flanking region downstream of the transcription start site. These results suggest functional TET2 is required for G6PD inhibition to increase gene expression and to reverse hypoxia-induced PH in mice. Furthermore, the inhibitor of G6PD activity (NEOU) decreased metabolic reprogramming, upregulated TET2 and lncPINT, and inhibited growth of control and diseased smooth muscle cells isolated from pulmonary arteries of normal individuals and idiopathic-PAH patients, respectively. Collectively, these findings demonstrate a previously unrecognized function for G6PD as a regulator of DNA methylation. These findings further suggest that G6PD acts as a link between reprogrammed metabolism and aberrant gene regulation and plays a crucial role in regulating the phenotype of cells implicated in the pathogenesis of PH, a debilitating disorder with a high mortality rate.

Joshi SR, Dhagia V, Gairhe S, Edwards JG, McMurtry IF, Gupte SA. MicroRNA-140 is elevated and mitofusin-1 is downregulated in the right ventricle of the Sugen5416/hypoxia/normoxia model of pulmonary arterial hypertension. Am J Physiol Heart Circ Physiol 311: H689 -H698, 2016. First published July 15, 2016 doi:10.1152/ajpheart.00264.2016.-Heart failure, a major cause of morbidity and mortality in patients with pulmonary arterial hypertension (PAH), is an outcome of complex biochemical processes. In this study, we determined changes in microRNAs (miRs) in the right and left ventricles of normal and PAH rats. Using an unbiased quantitative miR microarray analysis, we found 1) miR- 21-5p, miR-31-5 and 3p, miR-140-5 and 3p, miR-208b-3p, miR-221-3p, miR-222-3p, miR-702-3p, and miR-1298 were upregulated (Ͼ2-fold; P Ͻ 0.05) in the right ventricle (RV) of PAH compared with normal rats; 2) miR-31-5 and 3p, and miR-208b-3p were upregulated (Ͼ2-fold; P Ͻ 0.05) in the left ventricle plus septum (LVϩS) of PAH compared with normal rats; 3) miR-187-5p, miR-208a-3p, and miR-877 were downregulated (Ͼ2-fold; P Ͻ 0.05) in the RV of PAH compared with normal rats; and 4) no miRs were up-or downregulated with Ͼ2-fold in LVϩS compared with RV of PAH and normal. Upregulation of miR-140 and miR-31 in the hypertrophic RV was further confirmed by quantitative PCR. Interestingly, compared with control rats, expression of mitofusin-1 (MFN1), a mitochondrial fusion protein that regulates apoptosis, and which is a direct target of miR-140, was reduced in the RV relative to LVϩS of PAH rats. We found a correlation between increased miR-140 and decreased MFN1 expression in the hypertrophic RV. Our results also demonstrated that upregulation of miR-140 and downregulation of MFN1 correlated with increased RV systolic pressure and hypertrophy. These results suggest that miR-140 and MFN1 play a role in the pathogenesis of PAH-associated RV dysfunction.Listen to this article's corresponding podcast at http://ajpheart. podbean.com/e/mir140-and-right-heart-hypertrophy/. miR; heart; hypertrophy; heart failure; pulmonary; hypertension; lungs; rats THE PATHOPHYSIOLOGY of pulmonary arterial hypertension (PAH) is heterogeneous. In PAH, pulmonary vascular resistance and arterial pressure are increased, and the right ventricle (RV) is hypertrophied in response to increased afterload/pressure overload. Increased afterload in PAH leads to myocardial dysfunction, tricuspid regurgitation with progressive annular dilatation, and ultimately RV failure (67).Heart failure, a major cause of mortality in PAH patients (4, 5), is a complex syndrome. In the failing hearts, oxidative stress is increased and the rate of cardiomyocyte apoptotic and autophagic death is augmented (6,49,51,60,62). Activation of these processes causes myocardial stiffening, dilatation, and loss of contractility (49, 51). However, the mechanisms that regulate apoptosis and autophagy in this complex pathology are unclear and are an area under investigation.MicroRNAs (miRs) are a class of small no...

. 20-HETE-induced mitochondrial superoxide production and inflammatory phenotype in vascular smooth muscle is prevented by glucose-6-phosphate dehydrogenase inhibition. Am J Physiol Heart Circ Physiol 310: H1107-H1117, 2016. First published February 26, 2016 doi:10.1152/ajpheart.00961.2015 produced by cytochrome P-450 monooxygenases in NA-DPH-dependent manner is proinflammatory, and it contributes to the pathogenesis of systemic and pulmonary hypertension. In this study, we tested the hypothesis that inhibition of glucose-6-phosphate dehydrogenase (G6PD), a major source of NADPH in the cell, prevents 20-HETE synthesis and 20-HETE-induced proinflammatory signaling that promotes secretory phenotype of vascular smooth muscle cells. Lipidomic analysis indicated that G6PD inhibition and knockdown decreased 20-HETE levels in pulmonary arteries as well as 20-HETEinduced 1) mitochondrial superoxide production, 2) activation of mitogen-activated protein kinase 1 and 3, 3) phosphorylation of ETS domain-containing protein Elk-1 that activate transcription of tumor necrosis factor-␣ gene (Tnfa), and 4) expression of tumor necrosis factor-␣ (TNF-␣). Moreover, inhibition of G6PD increased protein kinase G1␣ activity, which, at least partially, mitigated superoxide production and Elk-1 and TNF-␣ expression. Additionally, we report here for the first time that 20-HETE repressed miR-143, which suppresses Elk-1 expression, and miR-133a, which is known to suppress synthetic/secretory phenotype of vascular smooth muscle cells. In summary, our findings indicate that 20-HETE elicited mitochondrial superoxide production and promoted secretory phenotype of vascular smooth muscle cells by activating MAPK1-Elk-1, all of which are blocked by inhibition of G6PD.20-HETE; TNF-␣; elk-1; mitogen-activated protein kinase 1 and 3; extracellular signal regulated kinase 2 and 1; protein kinase G; miRs 20-HYDROXYEICOSATETRAEONIC acid (20-HETE), the -hydroxylation metabolite of arachidonic acid (AA), is produced by cytochrome P-450 monooxygenases of the (CYP4A and CYP4F gene) families in an NADPH-dependent manner (49). 20-HETE is proinflammatory and it regulates vascular and renal function (49). It also plays a critical role in the pathogenesis of systemic hypertension, renal stenosis, and atherosclerosis (27,63,65). 20-HETE increased by hypoxia inhibits hypoxia-induced pulmonary artery constriction (69). However, its role in the hypoxia-induced inflammation of pulmonary arteries or lungs is yet unclear. NEWS & NOTEWORTHY 20-Hydroxyeicosatetraeonic acid (20-HETE) plays a criticalRecently, our laboratory also found that 20-HETE is involved in promoting prolonged hypoxia-induced pulmonary vasoconstriction and that glucose-6-phosphate dehydrogenase (G6PD), which is a major producer of NADPH in the cell, and cytochrome P-450 monooxygenase enzymes are functionally coupled in vascular smooth muscle tissue (unpublished observations). G6PD inhibition relaxes pulmonary arteries by decreasing intracellular calcium (20), prevents switching of vascular smooth ...

Objective- Unreliable antibodies often hinder the accurate detection of an endogenous protein, and this is particularly true for the cardiac and smooth muscle cofactor, MYOCD (myocardin). Accordingly, the mouse Myocd locus was targeted with 2 independent epitope tags for the unambiguous expression, localization, and activity of MYOCD protein. Approach and Results- 3cCRISPR (3-component clustered regularly interspaced short palindromic repeat) was used to engineer a carboxyl-terminal 3×FLAG or 3×HA epitope tag in mouse embryos. Western blotting with antibodies to each tag revealed a MYOCD protein product of ≈150 kDa, a size considerably larger than that reported in virtually all publications. MYOCD protein was most abundant in some adult smooth muscle-containing tissues with surprisingly low-level expression in the heart. Both alleles of Myocd are active in aorta because a 2-fold increase in protein was seen in mice homozygous versus heterozygous for FLAG-tagged Myocd. ChIP (chromatin immunoprecipitation)-quantitative polymerase chain reaction studies provide proof-of-principle data demonstrating the utility of this mouse line in conducting genome-wide ChIP-seq studies to ascertain the full complement of MYOCD-dependent target genes in vivo. Although FLAG-tagged MYOCD protein was undetectable in sections of adult mouse tissues, low-passaged vascular smooth muscle cells exhibited expected nuclear localization. Conclusions- This report validates new mouse models for analyzing MYOCD protein expression, localization, and binding activity in vivo and highlights the need for rigorous authentication of antibodies in biomedical research.

Epoxyeicosatrienoicacids (EETs), synthesized from arachidonic acid by epoxygenases of the CYP2C and CYP2J gene subfamilies, contribute to hypoxic pulmonary vasoconstriction (HPV) in mice. Despite their roles in HPV, it is controversial whether EETs mediate or ameliorate pulmonary hypertension (PH). A recent study showed that deficiency of Cyp2j did not protect male and female mice from hypoxia-induced PH. Since CYP2C44 is a functionally important epoxygenase, we hypothesized that knockout of the Cyp2c44 gene would protect both sexes of mice from hypoxia-induced PH. We tested this hypothesis in wild-type (WT) and Cyp2c44 knockout (Cyp2c44 (-/-)) mice exposed to normoxia (room air) and hypoxia (10% O2) for 5 weeks. Exposure of WT and Cyp2c44 (-/-) mice to hypoxia resulted in pulmonary vascular remodeling, increased pulmonary artery resistance, and decreased cardiac function in both sexes. However, in female Cyp2c44 (-/-) mice, compared with WT mice, (1) pulmonary artery resistance and right ventricular hypertrophy were greater, (2) cardiac index was lower, (3) left ventricular and arterial stiffness were higher, and (4) plasma aldosterone levels were higher, but (5) there was no difference in levels of EET in lungs and heart. Paradoxically and unexpectedly, we found that Cyp2c44 disruption exacerbated hypoxia-induced PH in female but not male mice. We attribute exacerbated PH in female Cyp2c44 (-/-) mice to elevated aldosterone and as-yet-unknown systemic factors. Therefore, we suggest a role for the human CYP2C genes in protecting women from severe PH and that this could be one of the underlying causes for a better 5-year survival rate in women than in men.