These results suggest that differential activation of the Rho-Rho-kinase and the ERK-p70S6 kinase pathways may play a critical role in CHF, and the Rho-Rho-kinase pathway is involved in the pathogenesis of cardiac dysfunction and cardiovascular remodeling. Thus, inhibition of the Rho-kinase pathway may be at least a potential therapeutic strategy for CHF.

Abstract-Vascular cell adhesion molecule-1 (VCAM-1) and reactive oxygen species play critical roles in early atherogenesis, and nitric oxide (NO) is an important regulator of the cardiovascular system. Although celiprolol, a specific ␤ 1 -antagonist with weak ␤ 2 -agonistic action, stimulates endothelial nitric oxide synthase (eNOS) production, the mechanisms remain to be determined. Because it was recently reported that phosphatidylinositol 3-kinase (PI3K) and its downstream effector Akt are implicated in the activation of eNOS and that regulation of VCAM-1 expression is mediated via nuclear factor-B (NF-B), we hypothesized that celiprolol activates phosphorylation of eNOS through the PI3K-Akt signaling pathway; that celiprolol modulates VCAM-1 expression, which is associated with inhibiting NF-B phosphorylation; and that celiprolol suppresses NAD(P)H oxidase p22phox, p47phox, gp91phox, and nox1 expression in the left ventricle of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. eNOS and Akt phosphorylation upregulated by celiprolol alone were suppressed by treatment with celiprolol plus wortmannin. Increased expression of VCAM-1, p22phox, p47phox, gp91phox, nox1, activated p65 NF-B, c-Src, p44/p42 extracellular signal-regulated kinases, and their downstream effector p90 ribosomal S6 kinase phosphorylation in DOCA rats was inhibited by celiprolol. Celiprolol administration resulted in a significant improvement in cardiovascular remodeling and suppression of transforming growth factor-␤1 gene expression. Key Words: receptors, adrenergic, ␤ Ⅲ adrenergic receptor blockers Ⅲ kinase Ⅲ nitric oxide Ⅲ oxidative stress Ⅲ cell adhesion molecules L eukocyte adhesion to the endothelium and infiltration into tissue have been found to contribute to the tissue damage and impairment of vascular perfusion in a broad array of systemic diseases, including atherosclerosis and hypertension. 1 Localized accumulation of leukocytes is mediated by the endothelial expression of specific adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1, or plateletendothelial cell adhesion molecule-1. 2 VCAM-1 is an early marker of endothelial activation and dysfunction, leukocyte infiltration, and vascular remodeling, and a recent study demonstrated that VCAM-1 plays a key role in early atherogenesis. 3 Endothelium-derived relaxing factor, nitric oxide (NO), is an important component of vascular homeostasis. 4 Recently, some investigators 5,6 have shown that the serine/ threonine kinase Akt, a downstream effector of phosphatidylinositol 3-OH kinase (PI3K), phosphorylates human endothelial NO synthase (eNOS) on serine 1177 in response to varied stimuli, such as growth factors and shear stress. Furthermore, expression of adhesion molecules, including VCAM-1, can be regulated by NO, and increased levels of NO are associated with decreased leukocyte adhesion molecule expression. 7 The mechanisms by which NO modulates expression of VCAM-1 are unclear. However, regulation of VCAM-1 expression...

Abstract-Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) may play an important role in atherosclerosis by inducing leukocyte adhesion molecules, such as intercellular and vascular cell adhesion molecule-1 (intercellular adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1]). We hypothesized that eplerenone, a novel selective aldosterone blocker, produces inhibition of LOX-1-mediated adhesion molecules, suppresses mitogenactivated protein (MAP) kinase and its downstream effector p90 ribosomal S6 kinase (p90RSK) through the protein kinase C⑀ (PKC⑀) pathway, and improves endothelial function by inhibition of Rho-kinase in the renal cortex of Dahl salt-sensitive hypertensive (DS) and salt-resistant (DR) rats. Eplerenone (10, 30, and 100 mg/kg per day) was given from the age of 6 weeks to the left ventricular hypertrophy stage (11 weeks) for 5 weeks. At 11 weeks, expression levels of LOX-1, ICAM-1, VCAM-1, and Rho-kinase were higher in DS rats than in DR rats and were decreased by eplerenone. Similarly, upregulated phosphorylation of PKC⑀, MAP kinase, and p90RSK in DS rats was also inhibited by eplerenone. In contrast, downregulated endothelial nitric oxide synthase mRNA was increased by eplerenone to a similar degree as after treatment with Y-27632, a selective Rho-kinase inhibitor. Eplerenone administration resulted in significant improvement in glomerulosclerosis (eplerenone 10 mg, Ϫ61%; 30 mg, Ϫ78%; and 100 mg, Ϫ84% versus DS; PϽ0.01, respectively) and urinary protein (10 mg, Ϫ78%; 30 mg, Ϫ87%; and 100 mg, Ϫ88% versus DS; PϽ0.01, respectively). These results suggest that the renoprotective effects of eplerenone may be partly caused by inhibition of LOX-1-mediated adhesion molecules and PKC⑀-MAP kinase-p90RSK pathway, and improvement in endothelial function.

Angiotensin II (Ang II) is a potent stimulator of plasminogen activator inhibitor-1 (PAI-1) expression, which is an important regulator of pathogenesis of atherosclerosis. Rho-kinase, a downstream target protein of small GTP-binding protein Rho, plays a key role for various cellular functions. We evaluated the cardioprotective effects of a specific Rho-kinase inhibitor, (R)-(ϩ)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide (Y-27632), and an Ang II type 1 receptor antagonist, candesartan, on PAI-1 gene expression and cardiovascular remodeling in Ang II-induced hypertensive rats. Rats given Ang II alone (200 ng ⅐ kg Ϫ1 ⅐ min Ϫ1 ) were compared with rats also receiving Ang II plus Y-27632 or Ang II plus candesartan. Ang II-induced PAI-1 mRNA up-regulation in the left ventricle was inhibited by Y-27632 and candesartan. In addition, increased RhoA protein, Rho-kinase, and c-fos gene expression, and myosin light chain phosphorylation were suppressed by Y-27632 and candesartan. In contrast, Y-27632 had no effect on Ang II-stimulated phospho-p42/p44 extracellular signalregulated kinases (ERK) and phospho-p70S6 kinase activities, which are reported to be involved in Ang II-induced protein synthesis. Moreover, activated Ang II-induced phosphorylation of ERK and p70S6 kinase were blocked by candesartan. Y-27632 or candesartan administration resulted in significant improvements in the wall-to-lumen ratio, perivascular fibrosis, and myocardial fibrosis. These results suggested that differential activation of Rho-kinase and ERK pathways may play a critical role in Ang II-induce PAI-1 gene expression, and upregulation of Rho-kinase plays a key role in the pathogenesis of Ang II-induced hypertensive rats. Thus, inhibition of the Rhokinase pathway may be at least a useful therapeutic strategy for treating cardiovascular remodeling.Left ventricular hypertrophy is the primary mechanism by which the heart compensates for a sustained increase in hemodynamic loading. Previous studies have shown that increased load itself is directly linked to hypertrophic growth in terms of both a quantitative increase in cardiac mass and qualitative changes in the cardiac phenotype (Cooper, 1987). However, the signaling mechanisms of hypertrophic cardiac growth are largely unknown. Activation of cell proliferation by hormones and growth factors has been shown to correlate with the intracellular activation of several interacting protein cascades. One of the kinases activated by all mitogens is p70S6 kinase, which leads to phosphorylation of the ribosomal S6 protein and increases the rate of translation of mRNAs containing a polypyrimidine tract. Previous studies have demonstrated P70S6 kinase activation in several cell types after either mitogenic stimulation, mechanical stretch, or integrin receptor engagement. Therefore, p70S6 kinase could play a key role in the load-induced hypertrophic growth process (Laser et al., 1998). Furthermore, the mitogen-activated protein kinases are a superfamily of proline-directed serine/threonin...