Rho Kinase–Mediated Vasoconstriction Is Important in Severe Occlusive Pulmonary Arterial Hypertension in Rats

Oka, Masahiko; Homma, Noriyuki; Taraseviciene‐Stewart, Laimute; Morris, Kenneth G.; Kraskauskas, Donatas; Burns, Nana; Voelkel, Norbert F.; McMurtry, Ivan F.

doi:10.1161/01.res.0000261658.12024.18

Cited by 313 publications

(306 citation statements)

References 49 publications

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“…The RhoA/ ROCK pathway is involved in the regulation of a variety of fundamental cell functions (28). Several studies (20,36,37) have demonstrated a critical role for this pathway in the regulation of systemic, pulmonary, and mesenteric vascular tone. Abnormal activation of the RhoA/ROCK pathway has been implicated in the pathogenesis of hypertension by Ca 2ϩ sensitization of the contractile apparatus (28,35,43).…”

Section: Discussionmentioning

confidence: 99%

Air pollution and cardiac remodeling: a role for RhoA/Rho-kinase

Zhao¹,

Yue²,

Xu³

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

110

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Exposure to ambient air pollution has been associated with increases in blood pressure. We have previously demonstrated activation of the Rho/Rho kinase pathway in experimental hypertension in rats. In this investigation, we evaluated the effects of particulate matter of Ͻ2.5 m (PM2.5) exposure on cardiovascular responses and remodeling and tested the effect of Rho kinase inhibition on these effects. C57BL/6 mice were exposed to concentrated ambient PM2.5 or filtered air for 12 wk followed by a 14-day ANG II infusion in conjunction with fasudil, a Rho kinase antagonist, or placebo treatment. Blood pressure was monitored, followed by analysis of vascular function and ventricular remodeling indexes. PM 2.5 exposure potentiated ANG II-induced hypertension, and this effect was abolished by fasudil treatment. Cardiac and vascular RhoA activation was enhanced by PM 2.5 exposure along with increased expression of the guanine exchange factors (GEFs) PDZRhoGEF and p115 RhoGEF in PM 2.5-exposed mice. Parallel with increased RhoA activation, PM 2.5 exposure increased ANG II-induced cardiac hypertrophy and collagen deposition, with these increases being normalized by fasudil treatment. In conclusion, PM2.5 potentiates cardiac remodeling in response to ANG II through RhoA/ Rho kinase-dependent mechanisms. These findings have implications for the chronic cardiovascular health effects of air pollution. hypertension; vasoconstrictors; angiotensin II AMBIENT AIR POLLUTION mediated by fine particulate matter (PM) of Ͻ2.5 m in aerodynamic diameter (PM 2.5 ) has been associated with adverse cardiovascular outcomes (8,31,39,49). One important mechanism is the elevation in blood pressure (BP) that may occur within hours to days after exposure to high concentrations of PM 2.5 (6,16,21,52). Recent studies (21, 58) have shown that commonly encountered levels of airborne pollutants can result in a prohypertensive response in humans that may be exaggerated in predisposed individuals. This potentiating effect of inhaled particulates has been noted with other chronic conditions or risk factors such as atherosclerosis, diabetes, and postmenopausal status (31,40,49). Although the precise mechanisms remain elusive, there is increasing evidence that PM 2.5 exposure results in rapid changes in the vasculature (7, 32). We (51) have previously shown that PM 2.5 exposure results in the activation of RhoA/Rho-kinase (ROCK) through ROS pathways and hypothesized that this important signaling cascade may mediate at least some of the prohypertensive effects of PM 2.5 . Given the important role of RhoA/ ROCK in a multitude of processes, including the regulation of smooth muscle tone, cellular migration, and hypertrophy (36,47), in the present study we examined the effect of PM 2.5 exposure on vascular function and cardiac remodeling and tested the effects of ROCK antagonism.

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Section: Discussionmentioning

confidence: 99%

Air pollution and cardiac remodeling: a role for RhoA/Rho-kinase

Zhao¹,

Yue²,

Xu³

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

110

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“…Thirty micrograms of lung tissue protein was used to perform Western blot analysis for SphK1 and SphK2 (Abgent; 1 ∶ 1,000) as described elsewhere. 24 Measurements of pulmonary and cardiac function in PAH rats Echocardiography. Symptoms of PAH in rats were monitored by echocardiography at 4, 8, 10, and 12 weeks after induction of PAH.…”

Section: Western Blot Analysismentioning

confidence: 99%

Sphingosine‐1‐Phosphate is Involved in the Occlusive Arteriopathy of Pulmonary Arterial Hypertension

et al. 2016

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Despite several advances in the pathobiology of pulmonary arterial hypertension (PAH), its pathogenesis is not completely understood. Current therapy improves symptoms but has disappointing effects on survival. Sphingosine-1-phosphate (S1P) is a lysophospholipid synthesized by sphingosine kinase 1 (SphK1) and SphK2. Considering the regulatory roles of S1P in several tissues leading to vasoconstriction, inflammation, proliferation, and fibrosis, we investigated whether S1P plays a role in the pathogenesis of PAH. To test this hypothesis, we used plasma samples and lung tissue from patients with idiopathic PAH (IPAH) and the Sugen5416/hypoxia/normoxia rat model of occlusive PAH. Our study revealed an increase in the plasma concentration of S1P in patients with IPAH and in early and late stages of PAH in rats. We observed increased expression of both SphK1 and SphK2 in the remodeled pulmonary arteries of patients with IPAH and PAH rats. Exogenous S1P stimulated the proliferation of cultured rat pulmonary arterial endothelial and smooth-muscle cells. We also found that 3 weeks of treatment of late-stage PAH rats with an SphK1 inhibitor reduced the increased plasma levels of S1P and the occlusive pulmonary arteriopathy. Although inhibition of SphK1 improved cardiac index and the total pulmonary artery resistance index, it did not reduce right ventricular systolic pressure or right ventricular hypertrophy. Our study supports that S1P is involved in the pathogenesis of occlusive arteriopathy in PAH and provides further evidence that S1P signaling may be a novel therapeutic target.Keywords: occlusive lesions, S1P, pulmonary, cardiac. Pulmonary arterial hypertension (PAH) remains debilitating and deadly despite advanced and expensive medical treatment. 1 Its pathogenic mechanisms have not been fully identified and therapeutically targeted. A limitation in the current treatment of patients with PAH is the inability of prostanoids, endothelin receptor blockers, phosphodiesterase inhibitors, or their various combinations to reverse the pulmonary arteriopathy. 2,3 An effective strategy in the development of more efficacious therapy would be to identify the molecular determinants of the arterial wall remodeling.Sphingosine-1-phosphate (S1P) is a biologically active lipid synthesized intracellularly by sphingosine kinase 1 (SphK1) and SphK2 and degraded by S1P lyase and various phosphatases. It is released by endothelial cells, red blood cells, activated platelets, and monocytes and has regulatory roles in several physiological and pathological processes. 4,5 Physiological levels of circulating S1P are vasculoprotective, whereas abnormal activation of SphK/S1P signaling is associated with diseases such as cancer, fibrosis, diabetes, and hypertension. [6][7][8][9][10] At high cellular or tissue levels, S1P is a proproliferative, antiapoptotic, promigratory, profibrotic, and proinflammatory signaling molecule. 11 SphK activity and S1P production are stimulated by numerous signals, including growth factors, cytokines, m...

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“…PAH was established in Wistar Kyoto rats by 1 injection (day 0) with SU 5416 (20 mg/kg subcutaneously) in combination with 2 weeks of continuous exposure to hypoxia, followed by 3 weeks in normoxic conditions. 31,32 Hemodynamic measurements RVSP and RV systemic pressure measurements were taken on day 21 before euthanasia, RVH assessment, and tissue harvest. Systemic arterial pressure was recorded via a cannula placed in the carotid artery, as previously described.…”

Section: Disease Modeling In Vivomentioning

confidence: 99%

Regulation and Function of miR‐214 in Pulmonary Arterial Hypertension

et al. 2016

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Dysregulation of microRNAs (miRNAs) can contribute to the etiology of diseases, including pulmonary arterial hypertension (PAH). Here we investigated a potential role for the miR-214 stem loop miRNA and the closely linked miR-199a miRNAs in PAH. All 4 miRNAs were upregulated in the lung and right ventricle (RV) in mice and rats exposed to the Sugen (SU) 5416 hypoxia model of PAH. Further, expression of the miRNAs was increased in pulmonary artery smooth muscle cells exposed to transforming growth factor β1 but not BMP4. We then examined miR-214 −/− mice exposed to the SU 5416 hypoxia model of PAH or normoxic conditions and littermate controls. There were no changes in RV systolic pressure or remodeling observed between the miR-214 −/− and wild-type hypoxic groups. However, we observed a significant increase in RV hypertrophy (RVH) in hypoxic miR-214 −/− male mice compared with controls. Further, we identified that the validated miR-214 target phosphatase and tensin homolog was upregulated in miR-214 −/− mice. Thus, miR-214 stem loop loss leads to elevated RVH and may contribute to the heart failure associated with PAH. Pulmonary arterial hypertension (PAH) is a disease characterized by narrowing of the small pulmonary arteries, leading to vascular remodeling, an elevation in pulmonary artery pressure, right ventricular hypertrophy (RVH), and heart failure. 1 Current therapies for PAH aim to reverse the endothelial dysfunction and vasoconstriction observed. 2 However, despite these therapies, PAH mortality rates remain high, and the 3-year survival of patients is only 54.9%. 3 Changes in the pulmonary vasculature are the primary cause of PAH; however, right ventricle (RV) function is a major determinant of the severity of symptoms and prognosis of pulmonary hypertension. Many therapies in development for PAH are focused on targeting the RV since heart failure is the ultimate cause of mortality in PAH. 4 PAH is predominant in females, with female ∶ male ratios of 1.4-4.1 ∶ 1. 5 Sexual dimorphism has also been observed in RV failure. Female PAH patients exhibit improved RV ejection fraction and survival compared with men. 6 This could be due at least in part to the protective effect of estrogen on RV function. 7,8 MicroRNAs (miRNAs) are involved in multiple cellular responses during normal development and disease; they act as posttranscriptional regulators to fine-tune protein synthesis. Evidence has emerged for a key role for miRNA in regulation of the cellular processes involved in PAH. We previously demonstrated that a range of miRNAs are dysregulated in rats exposed to models of PAH. 9 Later studies have shown that miR-21, the miR-143/145 cluster, miR-27a, the miR-17-92 cluster, miR-124, miR-150, miR-138, miR-190, miR-204, miR-206, miR-210, and miR-328 play a role in the development of PAH. 10 Multiple miRNAs could potentially be targeted in concert as therapeutics in PAH. 11 MicroRNA miR-214 is transcribed as a bicistronic primary transcript, which is processed to generate 4 separate mature miRNAs...

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Rho Kinase–Mediated Vasoconstriction Is Important in Severe Occlusive Pulmonary Arterial Hypertension in Rats

Cited by 313 publications

References 49 publications

Air pollution and cardiac remodeling: a role for RhoA/Rho-kinase

Air pollution and cardiac remodeling: a role for RhoA/Rho-kinase

Sphingosine‐1‐Phosphate is Involved in the Occlusive Arteriopathy of Pulmonary Arterial Hypertension

Regulation and Function of miR‐214 in Pulmonary Arterial Hypertension

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