Role of Jagged1-Hey1 Signal in Angiotensin II-induced Impairment of Myocardial Angiogenesis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Angiotensin II (Ang II) is a major contributor to the development of heart failure. However, the molecular and cellular mechanisms that underlie this process remain elusive. Inadequate angiogenesis in the myocardium leads to a transition from cardiac hypertrophy to dysfunction, and our previous study showed that Ang II significantly impaired the angiogenesis response. The current study was designed to examine the role of Jagged1-Notch signaling in the effect of Ang II during impaired angiogenesis and cardiac hypertrophy.</p><p><b>METHODS</b>Ang II was subcutaneously infused into 8-week-old male C57BL/6 mice at a dose of 200 ng·kg-1·min-1 for 2 weeks using Alzet micro-osmotic pumps. N-[N-(3, 5-difluorophenacetyl)-L-alanyl]-S-phenylglycine tert-butyl ester (DAPT), a γ-secretase inhibitor, was injected subcutaneously during Ang II infusion at a dose of 10.0 mg·kg-1·d-1. Forty mice were divided into four groups (n = 10 per group): control group; Ang II group, treated with Ang II; DAPT group, treated with DAPT; and Ang II + DAPT group, treated with both Ang II and DAPT. At the end of experiments, myocardial (left ventricle [LV]) tissue from each experimental group was evaluated using immunohistochemistry, Western blotting, and real-time polymerase chain reaction. Data were analyzed using one-way analysis of variance test followed by the least significant difference method or independent samples t-test.</p><p><b>RESULTS</b>Ang II treatment significantly induced cardiac hypertrophy and impaired the angiogenesis response compared to controls, as shown by hematoxylin and eosin (HE) staining and immunohistochemistry for CD31, a vascular marker (P < 0.05 for both). Meanwhile, Jagged1 protein was significantly increased, but gene expression for both Jag1 and Hey1 was decreased in the LV following Ang II treatment, compared to that in controls (relative ratio for Jag1 gene: 0.45 ± 0.13 vs. 0.84 ± 0.15; relative ratio for Hey1 gene: 0.51 ± 0.08 vs. 0.91 ± 0.09; P < 0.05). All these cellular and molecular effects induced by Ang II in the hearts of mice were reduced by DAPT treatment. Interestingly, Ang II stimulated Hey1, a known Notch target, but did not affect the expression of Hey2, another Notch target gene.</p><p><b>CONCLUSIONS</b>A Jagged1-Hey1 signal might mediate the impairment of angiogenesis induced by Ang II during cardiac hypertrophy.</p>

Implication of elevated expression of receptor for activated C kinase 1 in mononuclear cells and coronary atherosclerotic plaques from patients with coronary artery disease / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the expression and clinical implication of receptor for activated C kinase 1 (RACK1) in mononuclear cells and coronary atherosclerotic plaques from patients with coronary artery disease.</p><p><b>METHODS</b>mRNA and protein expressions of RACK1 were detected in mononuclear cells from 29 patients with stable angina pectoris (SAP), 41 patients with acute coronary syndrome (ACS) and 30 healthy volunteers. RACK1 protein expression was also detected by immunohistochemistry in 17 coronary atherosclerotic plaques and 6 normal autopsy coronary samples.</p><p><b>RESULTS</b>(1) mRNA expression of RACK1 was significantly upregulated in mononuclear cells from patients with ACS compared with those from patients with SAP (18.71 ± 5.45 vs. 12.18 ± 4.14, P < 0.05), and the latter was also significantly higher than in healthy controls (12.18 ± 4.14 vs. 3.65 ± 1.57, P < 0.05). (2) Similar changes were observed for protein expression of RACK1 for the three groups. (3) Increased expression of RACK1 was found in atherosclerotic plaques, especially in unstable plaques, positive RACK1 stain was evidenced in foam cells, inflammatory cells, smooth muscle cells and endothelial cells.</p><p><b>CONCLUSIONS</b>The expression of RACK1 is significantly upregulated in mononuclear cells from patients with coronary artery disease, especially in patients with ACS, and in coronary atherosclerotic plaques, especially in unstable plaques. Our results thus suggest that RACK1 might play an important role in the development and progression of coronary artery disease.</p>

Effect of urotensin II on proliferative potential and phosphorylation of extracellular signal-regulated kinase 1/2 of adventitial fibroblasts from spontaneously hypertensive rat / 中国医学科学院学报

<p><b>OBJECTIVE</b>To study the effect of urotensin II ( U II ) on the proliferative potential of adventitial fibroblasts (AFs) from spontaneously hypertensive rat (SHR) and to determine whether extracellular signal-regulated kinase 1/2 (ERK1/2) pathway is involved in this progress.</p><p><b>METHODS</b>3H-thymidine incorporation test was used to estimate the U II -induced proliferative potential of AFs from SHR and the influence of Urantide (U II receptor antagonist) and PD98059 (ERK1/2 inhibitor). Western blotting was used to test the U II -induced ERK1/2 phosphorylation as well as the effect of Urantide and PD98059 on U II -induced ERKl/2 phosphorylation.</p><p><b>RESULTS</b>U 11 increased the proliferative potential of AFs from SHR in a dose-dependent way. Urantide and PD98059 wholly or partly inhibited U II -induced proliferation of SHR-AFs. In SHR-AFs, U II induced the phosphorylation of ERK1/2 in a time-dependent way, which was completely inhibited by Urantide and PD98059.</p><p><b>CONCLUSION</b>U II can increase the proliferative potential of AFs from SHR and ERK1/2 pathway is partly involved in this progress.</p>