Twenty years ago, Rho-kinase was identified as an important downstream effector of the small GTP-binding protein, RhoA. Thereafter, a series of studies demonstrated the important roles of Rho-kinase ...in the cardiovascular system. The RhoA/Rho-kinase pathway is now widely known to play important roles in many cellular functions, including contraction, motility, proliferation, and apoptosis, and its excessive activity induces oxidative stress and promotes the development of cardiovascular diseases. Furthermore, the important role of Rho-kinase has been demonstrated in the pathogenesis of vasospasm, arteriosclerosis, ischemia/reperfusion injury, hypertension, pulmonary hypertension, and heart failure. Cyclophilin A is secreted by vascular smooth muscle cells and inflammatory cells and activated platelets in a Rho-kinase-dependent manner, playing important roles in a wide range of cardiovascular diseases. Thus, the RhoA/Rho-kinase pathway plays crucial roles under both physiological and pathological conditions and is an important therapeutic target in cardiovascular medicine. Recently, functional differences between ROCK1 and ROCK2 have been reported in vitro. ROCK1 is specifically cleaved by caspase-3, whereas granzyme B cleaves ROCK2. However, limited information is available on the functional differences and interactions between ROCK1 and ROCK2 in the cardiovascular system in vivo. Herein, we will review the recent advances about the importance of RhoA/Rho-kinase in the cardiovascular system.
Although postcapillary pulmonary hypertension (PH) is an important prognostic factor for patients with heart failure (HF), its pathogenesis remains to be fully elucidated. To elucidate the different ...roles of Rho-kinase isoforms, ROCK1 and ROCK2, in cardiomyocytes in response to chronic pressure overload, we performed transverse aortic constriction (TAC) in cardiac-specific ROCK1-deficient (cROCK1
−/−) and ROCK2-deficient (cROCK2
−/−) mice. Cardiomyocyte-specific ROCK1 deficiency promoted pressure-overload-induced cardiac dysfunction and postcapillary PH, whereas cardiomyocyte-specific ROCK2 deficiency showed opposite results. Histological analysis showed that pressure-overload-induced cardiac hypertrophy and fibrosis were enhanced in cROCK1
−/− mice compared with controls, whereas cardiac hypertrophy was attenuated in cROCK2
−/− mice after TAC. Consistently, the levels of oxidative stress were up-regulated in cROCK1
−/− hearts and down-regulated in cROCK2
−/− hearts compared with controls after TAC. Furthermore, cyclophilin A (CyPA) and basigin (Bsg), both of which augment oxidative stress, enhanced cardiac dysfunction and postcapillary PH in cROCK1
−/− mice, whereas their expressions were significantly lower in cROCK2
−/− mice. In clinical studies, plasma levels of CyPA were significantly increased in HF patients and were higher in patients with postcapillary PH compared with those without it. Finally, high-throughput screening demonstrated that celastrol, an antioxidant and antiinflammatory agent, reduced the expressions of CyPA and Bsg in the heart and the lung, ameliorating cardiac dysfunction and postcapillary PH induced by TAC. Thus, by differentially affecting CyPA and Bsg expressions, ROCK1 protects and ROCK2 jeopardizes the heart from pressure-overload HF with postcapillary PH, for which celastrol may be a promising agent.
Endothelial AMP-activated protein kinase (AMPK) plays an important role for vascular homeostasis, and its role is impaired by vascular inflammation. However, the role of endothelial AMPK in the ...pathogenesis of pulmonary arterial hypertension (PAH) remains to be elucidated.
To determine the role of endothelial AMPK in the development of PAH.
Immunostaining showed that endothelial AMPK is downregulated in the pulmonary arteries of patients with PAH and hypoxia mouse model of pulmonary hypertension (PH). To elucidate the role of endothelial AMPK in PH, we used endothelial-specific AMPK-knockout mice (eAMPK(-/-)), which were exposed to hypoxia. Under normoxic condition, eAMPK(-/-) mice showed the normal morphology of pulmonary arteries compared with littermate controls (eAMPK(flox/flox)). In contrast, development of hypoxia-induced PH was accelerated in eAMPK(-/-) mice compared with controls. Furthermore, the exacerbation of PH in eAMPK(-/-) mice was accompanied by reduced endothelial function, upregulation of growth factors, and increased proliferation of pulmonary artery smooth muscle cells. Importantly, conditioned medium from endothelial cells promoted pulmonary artery smooth muscle cell proliferation, which was further enhanced by the treatment with AMPK inhibitor. Serum levels of inflammatory cytokines, including tumor necrosis factor-α and interferon-γ were significantly increased in patients with PAH compared with healthy controls. Consistently, endothelial AMPK and cell proliferation were significantly reduced by the treatment with serum from patients with PAH compared with controls. Importantly, long-term treatment with metformin, an AMPK activator, significantly attenuated hypoxia-induced PH in mice.
These results indicate that endothelial AMPK is a novel therapeutic target for the treatment of PAH.
Pulmonary arterial hypertension is characterized by abnormal proliferation of pulmonary artery smooth muscle cells and vascular remodeling, which leads to right ventricular (RV) failure. Bsg ...(Basigin) is a transmembrane glycoprotein that promotes myofibroblast differentiation, cell proliferation, and matrix metalloproteinase activation. CyPA (cyclophilin A) binds to its receptor Bsg and promotes pulmonary artery smooth muscle cell proliferation and inflammatory cell recruitment. We previously reported that Bsg promotes cardiac fibrosis and failure in the left ventricle in response to pressure-overload in mice. However, the roles of Bsg and CyPA in RV failure remain to be elucidated. Approach and Results: First, we found that protein levels of Bsg and CyPA were upregulated in the heart of hypoxia-induced pulmonary hypertension (PH) in mice and monocrotaline-induced PH in rats. Furthermore, cardiomyocyte-specific Bsg-overexpressing mice showed exacerbated RV hypertrophy, fibrosis, and dysfunction compared with their littermates under chronic hypoxia and pulmonary artery banding. Treatment with celastrol, which we identified as a suppressor of Bsg and CyPA by drug screening, decreased proliferation, reactive oxygen species, and inflammatory cytokines in pulmonary artery smooth muscle cells. Furthermore, celastrol treatment ameliorated RV systolic pressure, hypertrophy, fibrosis, and dysfunction in hypoxia-induced PH in mice and SU5416/hypoxia-induced PH in rats with reduced Bsg, CyPA, and inflammatory cytokines in the hearts and lungs.
These results indicate that elevated Bsg in pressure-overloaded RV exacerbates RV dysfunction and that celastrol ameliorates RV dysfunction in PH model animals by suppressing Bsg and its ligand CyPA. Thus, celastrol can be a novel drug for PH and RV failure that targets Bsg and CyPA. Graphic Abstract: A graphic abstract is available for this article.
Zinc regulates the oxidative stress and inflammatory signaling cascade and affects the development and deterioration of cardiovascular disease. We investigated the prognosis of developing heart ...failure in patients with myocardial infarction.
Patients with myocardial infarction (n = 243) were divided using the median value of zinc concentration on admission into low (< 66 µg/dL at admission, n = 111) and high zinc group (≥ 66 µg/dL at admission, n = 132). During follow-up (mean ± SD: 734 ± 597 days; median 691 days), admission due to heart failure was observed in 12 patients: 10 and 2 cases in the low and high zinc groups, respectively.
The risk of admission due to heart failure was significantly higher in the low zinc than in the high zinc group (P = 0.0043). Relative to the high zinc group, the hazard ratio for admission due to heart failure was 15.7 (95% confidence interval 1.11-221, P = 0.042) via adjusted Cox proportional hazards analysis. Even after propensity score matching, the risk of admission due to heart failure was significantly higher in the low zinc than in the high zinc group (P = 0.048).
Low serum zinc concentration may be a risk factor for admission due to heart failure after myocardial infarction.
The recurrence rate of acute coronary syndrome (ACS) in patients after first-time myocardial infarction (MI) is over ten times higher than in the general population. However, it is unclear whether ...patients with multiple-time MI have an even higher recurrence rate of MI. This study aimed to compare the recurrence rate in patients with multiple-time MI with the rate in patients after first-time MI. We retrospectively studied 794 consecutive MI patients who were discharged. Recurrent ACS was investigated in patients with previous MI (n = 46) and without previous MI (n = 748). During the follow-up periods (mean ± SD: 757 ± 733 days), recurrent ACS occurred in 47 cases without previous MI and in 7 cases with previous MI. Kaplan-Meier analysis revealed that the risk of recurrent ACS was significantly higher in patients with previous MI than in patients without previous MI. ACS recurrence rates one year from the onset were 4.2% in patients without previous MI and 11.9% in patients with previous MI. Landmark analysis revealed that the higher recurrence rate in patients with previous MI was as high as 14.1% from 1 year after the onset to 2 years. In conclusion, the risk of recurrent ACS may be significantly higher in patients with multiple-time MI than in patients after first-time MI.
Basigin (Bsg) is a transmembrane glycoprotein that activates matrix metalloproteinases and promotes inflammation. However, the role of Bsg in the pathogenesis of cardiac hypertrophy and failure ...remains to be elucidated. We examined the role of Bsg in cardiac hypertrophy and failure in mice and humans.
We performed transverse aortic constriction in Bsg(+/-) and in wild-type mice. Bsg(+/-) mice showed significantly less heart and lung weight and cardiac interstitial fibrosis compared with littermate controls after transverse aortic constriction. Both matrix metalloproteinase activities and oxidative stress in loaded left ventricle were significantly less in Bsg(+/-) mice compared with controls. Echocardiography showed that Bsg(+/-) mice showed less hypertrophy, less left ventricular dilatation, and preserved left ventricular fractional shortening compared with littermate controls after transverse aortic constriction. Consistently, Bsg(+/-) mice showed a significantly improved long-term survival after transverse aortic constriction compared with Bsg(+/+) mice, regardless of the source of bone marrow (Bsg(+/+) or Bsg(+/-)). Conversely, cardiac-specific Bsg-overexpressing mice showed significantly poor survival compared with littermate controls. Next, we isolated cardiac fibroblasts and examined their responses to angiotensin II or mechanical stretch. Both stimuli significantly increased Bsg expression, cytokines/chemokines secretion, and extracellular signal-regulated kinase/Akt/JNK activities in Bsg(+/+) cardiac fibroblasts, all of which were significantly less in Bsg(+/-) cardiac fibroblasts. Consistently, extracellular and intracellular Bsg significantly promoted cardiac fibroblast proliferation. Finally, serum levels of Bsg were significantly elevated in patients with heart failure and predicted poor prognosis.
These results indicate the crucial roles of intracellular and extracellular Bsg in the pathogenesis of cardiac hypertrophy, fibrosis, and failure in mice and humans.
Background Circulating proteins are exposed to vascular endothelial layer and influence their functions. Among them, adipsin is a member of the trypsin family of peptidases and is mainly secreted ...from adipocytes, monocytes, and macrophages, catalyzing the rate-limiting step of the alternative complement pathway. However, its pathophysiological role in cardiovascular disease remains to be elucidated. Here, we examined whether serum adipsin levels have a prognostic impact in patients with coronary artery disease. Methods and Results In 370 consecutive patients undergoing diagnostic coronary angiography, we performed a cytokine array analysis for screening serum levels of 50 cytokines/chemokines and growth factors. Among them, classification and regression analysis identified adipsin as the best biomarker for prediction of their long-term prognosis (median 71 months; interquartile range, 55-81 months). Kaplan-Meier curve showed that higher adipsin levels (≥400 ng/mL) were significantly associated with all-cause death (hazard ratio HR, 4.2; 95% CI, 1.7-10.6
<0.001) and rehospitalization (HR, 2.4; 95% CI, 1.7-3.5
<0.001). Interestingly, higher high-sensitivity C-reactive protein levels (≥1 mg/L) were significantly correlated with all-cause death (HR, 3.2; 95% CI, 1.7-5.9
<0.001) and rehospitalization (HR, 1.5, 95% CI, 1.1-1.9
<0.01). Importantly, the combination of adipsin (≥400 ng/mL) and high-sensitivity C-reactive protein (≥1 mg/L) was more significantly associated with all-cause death (HR, 21.0; 95% CI, 2.9-154.1
<0.001). Finally, the receiver operating characteristic curve demonstrated that serum adipsin levels predict the death caused by acute myocardial infarction in patients with coronary artery disease (C-statistic, 0.847). Conclusions These results indicate that adipsin is a novel biomarker that predicts all-cause death and rehospitalization in patients with coronary artery disease, demonstrating the novel aspects of the alternative complementary system in the pathogenesis of coronary artery disease.
Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are fatal diseases; however, their pathogenesis still remains to be elucidated. We have recently ...screened novel pathogenic molecules and have performed drug discovery targeting those molecules. Pulmonary artery smooth muscle cells (PASMCs) in patients with PAH (PAH-PASMCs) have high proliferative properties like cancer cells, which leads to thickening and narrowing of distal pulmonary arteries. Thus, we conducted a comprehensive analysis of PAH-PASMCs and lung tissues to search for novel pathogenic proteins. We validated the pathogenic role of the selected proteins by using tissue-specific knockout mice. To confirm its clinical significance, we used patient-derived blood samples to evaluate the potential as a biomarker for diagnosis and prognosis. Finally, we conducted a high throughput screening and found inhibitors for the pathogenic proteins.
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