AT2 Receptor Stimulation Inhibits Vascular Smooth Muscle Cell Senescence Induced by Angiotensin II and Hyperglycemia.

BACKGROUND: Hyperglycemia has been widely reported to induce vascular senescence. We have previously demonstrated that angiotensin II (Ang II) could promote brain vascular smooth muscle cell (VSMC) senescence, and its type 2 (AT2) receptor deletion could enhance VSMC senescence. Therefore, we examined the possible cross-talk between Ang II and hyperglycemia on VSMC senescence, and the roles of AT2 receptor agonist, compound 21 (C21) on it. METHODS: Aortic VSMCs were prepared from adult male mice and stimulated with Ang II and/or high glucose (Glu) and/or C21 and/or an autophagy inhibitor, 3-methyladenine (3-MA), and/or an autophagy agonist, rapamycin (RAP) for the indicated times. Cellular senescence, oxidative stress, and protein expressions were evaluated. RESULTS: Combination treatment with Ang II and Glu synergistically increased the proportion of VSMC senescent area compared with control group and each treatment alone, which was almost completely attenuated by C21 treatment. Moreover, combination treatment induced significant changes in the levels of superoxide anion, the expressions of p21 and pRb, and the ratio of LC3B II/I expression, which were also significantly attenuated by C21 treatment. The proportion of VSMC senescent area and the levels of superoxide anion by combination treatment were increased after 3-MA treatment, and the proportion of senescent area and the expressions of p21 and pRb were decreased after RAP treatment, both of which were further attenuated by C21 treatment. CONCLUSIONS: Ang II and hyperglycemia synergistically promoted VSMC senescence, at least partly through the participation by autophagy, oxidative stress, and p21-pRb pathway, which could be inhibited by C21.

[Effect of Silencing FMOD on Proliferation and Migration of H322 Cells and Its Mechanism].

OBJECTIVE: To investigate the regulation of fibromodulin (FMOD) on proliferation, adhesion and migration of non-small cell lung cancer cell line H322, and discuss its action mechanism. METHODS: H322 cells were randomly divided into control group, small interfering RNA (siRNA) silencing FMOD ( FMOD siRNA) group and control siRNA (Con siRNA) group. FMOD siRNA and Con siRNA were transfected into H322 cells. The cell viability of each group was detected by CCK-8 method. The adhesion ability of cells was detected by fluorescein diacetate (FDA) fluorescent staining. The cell migration ability was detected by Transwell method. Real time-PCR was used to detect the mRNA expressions of Cyclin D1, intercellular adhesion molecule -1 （ICAM-1）, E-cadherin, FMOD, transforming growth factor-ß (TGF-ß), Smad2, Smad3, Smad4 and Smad7 in cells. The protein expressions of Cyclin D1, ICAM-1, E-cadherin, FMOD, TGF-ß1, Smad2, Smad3, Smad4 and Smad7 were detected by Western blot. RESULTS: Compared with the Con siRNA group, the cell viability, cell adhesion and migration ability of the FMOD siRNA group were decreased, and the difference was statistically significant ( P<0.01). There was no significant difference between the control group and the Con siRNA group. Real time-PCR and Western blot results showed that the mRNA and protein expression levels of Cyclin D1, ICAM-1, TGF-ß1, Smad2, Smad3 and Smad4 were decreased in FMOD siRNA group, compared with Con siRNA group, while the mRNA and protein expression levels of E-cadherin and Smad7 are elevated. CONCLUSION: Silencing of the FMOD gene significantly reduces the proliferation, adhesion and migration of H322 cells, which may be conducted by inhibiting the TGF-ß/Smad signaling pathway.

P27 Promotes TGF-ß-Mediated Pulmonary Fibrosis via Interacting with MTORC2.

Pulmonary fibrosis (PF), a progressive and life-threatening pulmonary disease, is the main pathological basis of interstitial lung disease (ILD) which includes the idiopathic pulmonary fibrosis (IPF). No effective therapeutic strategy for pulmonary fibrosis has been established. TGF-ß signaling has emerged as the vital regulator of PF; however, the detailed molecular mechanisms of TGF-ß in PF were uncertain. In the present study, we proved that inhibition of MTORC2 suppresses the expression of P27 in MRC5 and HLF cells. And in bleomycin-induced PF model, the expression of α-SMA and P27 was upregulated. Moreover, TGF-ß application increased the level of α-SMA, vimentin, and P27 in MRC5 and HLF cells. Furthermore, P27 overexpression advanced the cell cycle process and promoted the proliferation of MRC5 and HLF cells. Finally, the rescue experiment showed that MTORC2 knockdown reversed P27 overexpression-induced cell cycle acceleration and proliferation. Thus, our results suggest that P27 is involved in TGF-ß-mediated PF, which was regulated by MTORC2, providing a novel insight into the development of PF.

Vitamin D Supplementation in the Treatment of Chronic Heart Failure: A Meta-analysis of Randomized Controlled Trials.

BACKGROUND: In recent years, there has been growing evidence that vitamin D deficiency is associated with the development and progression of chronic heart failure (CHF). HYPOTHESIS: Additional supplementation of vitamin D may have protective effects in patients with CHF. METHODS: We searched PubMed, Embase, and Cochrane databases through June 2015 and included 7 randomized controlled trials that investigated the effects of vitamin D on cardiovascular outcomes in patients with CHF. Then, we performed a meta-analysis of clinical trials to confirm whether vitamin D supplementation is beneficial in CHF patients. The weighted mean difference (WMD) and 95% confidence interval (CI) were calculated using fixed- or random-effects models. RESULTS: Our pooled results indicated that additional supplementation of vitamin D was not superior to conventional treatment in terms of left ventricular ejection fraction, N-terminal pro-B-type natriuretic peptide, and 6-minute walk distance. Moreover, vitamin D supplementation was associated with significant decreases in the levels of tumor necrosis factor-α (WMD: -2.42 pg/mL, 95% CI: -4.26 to -0.57, P < 0.05), C-reactive protein (WMD: -0.72 mg/L, 95% CI: -1.42 to -0.02, P < 0.05), and parathyroid hormone (WMD: -13.44 pg/mL, 95% CI: -21.22 to -5.67, P < 0.05). CONCLUSIONS: Vitamin D supplementation may decrease serum levels of parathyroid hormone and inflammatory mediators in CHF patients, whereas it has no beneficial effects on improvement of left ventricular function and exercise tolerance.

Influence of insulin resistance on in-stent restenosis in patients undergoing coronary drug-eluting stent implantation after long-term angiographic follow-up.

OBJECTIVE: Previous studies have reported that insulin resistance is related to early in-stent restenosis (ISR) after coronary stenting. This study aimed to evaluate the influence of insulin resistance on the long-term angiographic outcome in patients undergoing coronary drug-eluting stent (DES) implantation. MATERIALS AND METHODS: Within a single hospital-based cohort of patients (n=529) who underwent coronary DES implantation, angiographic follow-up was performed successfully for 417 study patients at 12-48 months after coronary stenting. ISR was defined as stenosis of at least 50% of the luminal diameter. Fasting plasma glucose and fasting plasma insulin were measured. Insulin resistance was expressed by the homeostasis model assessment index (HOMA-IRI). RESULTS: Among the 417 patients who completed angiographic follow-up (mean 17.5±10.2 months), 58 patients (13.9%) had ISR whereas the remaining 359 patients (86.1%) did not have ISR. Patients with ISR had higher insulin resistance index (IRI) than nonrestenosis patients (P=0.004). Multiple logistic regression analysis (logit) showed that IRI was associated significantly with ISR (adjusted odds ratio 1.476, 95% confidence interval 1.227-1.776; P<0.001). In the nondiabetes subgroup of 309 patients, IRI was higher in patients with ISR than in nonrestenosis patients, as confirmed in a separate logit analysis (adjusted odds ratio 1.456, 95% confidence interval 1.152-1.839; P=0.002). Multiple linear regression analysis showed that IRI was associated significantly with in-stent diameter stenosis degree (P=0.043). CONCLUSION: Insulin resistance was associated with ISR in patients undergoing coronary DES implantation at long-term angiographic follow-up.

[Fluorescence study on the interaction of narrow distribution low polymerization degree chitooligosaccharides and human serum albumin].

Chitosan (CTS), a linear binary copolymer of (1-->8)-linked 2-acetamido-2-deoxy-beta-D-glucopyranose (GlcNAc unit) and 2-amino-2-deoxy-beta-D-glucopyranose (GlcNH2 unit), is derived from chitin by alkaline deacetylation. In the present work, the narrow molecular weight distribution chitooligosaccharides were prepared by degraded CTS with a microwave-assisted-cleavage method of metal-coordinating template-absorption catalytic oxidation. Under physiological pH conditions, the interaction of CTS and the narrow distribution chitooligosaccharides with Human serum albumin (HSA) was preliminarily explored by fluorescence spectra. Low molecular weight CTS in different concentration was added into HSA solution respectively, the absorptivity of the HSA solution decreased considerably. This phenomenon indicated that there was an interaction between these six different low molecular weight CTS with HSA, and the smaller the DP of the narrow distribution chitooligosaccharides, the stronger the interaction with HSA. However, the interaction gradually failed in as the DP was less than eight. The interaction almost disappeared when using glucosamine, the final product of degraded CTS, which revealed that there was a scale effect between chain-like CTS molecule and protein biomacromolecule. The results suggest that the strongest interaction binding occurs in CTS with DP approximately =8. Whether the DP increases or decreases, the interaction will weaken.

[Synthesis of sulfur-contained D(+)-glucosamine metal complexes and interaction with DNA and serum albumin].

Four sulfur-contained D(+)-glucosamine metal complexes were synthesized (M-GLUS, M = Co, Cu, Ni and Zn)and characterized by elementary analysis, molar conductance, and proton nuclear magnetic resonance. The yield of the complex was about 70%, and it dissolved easily in water. The ligand coordinates with metalions mainly between sulphur and metalions, the coordination molar ratio of the ligand to metalion was 2 : 1, and the molar conductivity indicated that all the complexes are nonelectrolyte. The mechanism of the interaction between metal complexes and calf thymus (ct) DNA in Tris buffer (pH = 7. 08), was studied by ultraviolet absorption and fluorescence spectroscopy. The results from varied experiments showed that the intensity of the maximal absorption peaks increased with gradual addition of metal complexes, but the metalions can decrease the maximal absorption and the ligand has no effect on it. Meanwhile, metal complexes could remarkably quench the emission intensity of the DNA-EB system, and the metal complexes could be bound to ct DNA. The quenching mechanism was discussed by Stern-Volmer's equation, the figure showed that it is influenced by static quenching and dynamic quenching, so the partial interaction of the complexes and ct DNA was the major mode. Under physiological pH condition, this study was designed to examine the effect of complexes on human serum albumin and bovine serum albumin by fluorescence. The binding constants and sites of the interaction with SA were analyzed by the Scatchard's equation, the results indicated that there was a strong interaction between the four metal complexes and serum albumin and the binding force was Co-GLUS > Zn-GLUS > Cu-GLUS > Cu-GLUS, and the binding site is only one.

[An experimental study of expression of angiotension converting enzyme 2 in myocardium and effect of telmisartan treatment in pressure-overloaded rats].

OBJECTIVE: To study the effect of hypertension and telmisartan treatment on the protein and gene expression of cardiac angiotensin-converting enzyme 2 (ACE2) in pressure-overloaded rats. METHODS: Coarctation of suprarenal abdominal aorta was reproduced in 8 week-old male Sprague-Dawley (SD) rats and then randomized into 4 groups, including a sham group (n=15), a suprarenal aortic coarctation group (model group, n=12), a suprarenal aortic coarctation with low-dose Telmisartan treatment group (low-dose group, 2 mgxkg(-1)xd(-1), n=11) and a suprarenal aortic coarctation with high-dose Telmisartan treatment group(high-dose group, 10 mgxkg(-1)xd(-1), n=13). Telmisartan or equivalent amount of normal saline was gavaged 24 hours before the operation and once every day afterwards for 3 weeks. At the end of 3 weeks, the concentrations of angiotensin (AngII) in plasma and myocardium were measured by radioimmunoassay. Changes in both protein quantity and gene expressions of both ACE2 and ACE were determined by Western blotting analysis and reverse transcription-polymerase chain reaction (RT-PCR) technique, respectively. RESULTS: Suprarenal abdominal aortic coarctation induced a significant increase in the plasma and myocardium AngII concentration [plasma: (495.1+/-55.6) ng/L vs. (269.2+/-39.5)ng/L, myocardium: (103.6+/-23.7) ng/g vs. (49.5+/-13.5) ng/g, both P<0.01] and expressions of gene and protein of ACE (P<0.01) and ACE2 (P<0.05). Telmisartan further increased the concentration of AngII in plasma and myocardium in a dose-dependent manner [plasma: (702.2+/-40.6) ng/L vs. (612.6+/-35.5) ng/L, myocardium (211.5+/-21.5) ng/g vs. (189.6+/-43.6) ng/g, both P<0.05], and induced a dose-dependent increase in both protein and gene expression of ACE2 (protein 1.16+/-0.06 vs. 0.79+/-0.04, gene 0.54+/-0.08 vs. 0.41+/-0.04, both P<0.05). Expression of ACE2 protein in low-dose and high-dose groups was increased by 1.0 and 1.58 folds respectively, and gene was increased by 1.3 and 1.6 folds (all P<0.05). The expression of ACE protein and gene in model group increased significantly (protein: 2.10+/-1.07 vs. 1.02+/-0.05, gene: 1.93+/-0.09 vs. 0.26+/-0.09, both P<0.01). Telmisartan had no significant effect on ACE gene and protein expressions (both P>0.05). CONCLUSION: Suprarenal abdominal aortic coarctation induced a significant increases of ACE and ACE2 gene and protein expressions. Telmisartan induces a dose-dependent increases of cardiac ACE2 gene and protein expression,which may be the mechanism of its therapeutic effects.

[Study on up-regulation of the expression of angiotensin-converting enzyme-2 in human umbilical vein endothelial cells by telmisartan].

OBJECTIVE: To investigate the effect of telmisartan on the protein and gene expression of angiotensin-converting enzyme-2 (ACE2) in human umbilical vein endothelial cells (HUVECs). METHODS: HUVECs were treated with various concentrations of telmisartan (10(-7), 10(-6) and 10(-5) mol/L) for 24 hours. In a time-control experiment, HUVECs were treated with telmisartan at the final concentration of 10(-6) mol/L for 6, 12 and 24 hours, respectively. In another experiment, HUVECs were treated with PD123319 (10(-6) mol/L) only or combined with same final concentration of telmisartan for 12 hours, respectively. Changes in both protein and gene expression of ACE2 were determined with Western blot analysis and reverse transcription-polymerase chain reaction (RT-PCR) technique, respectively. RESULTS: Telmisartan induced a concentration and time dependent increase in both protein and gene expression of ACE2 (P<0.05 or P<0.01). Compared with control group, treatment of HUVECs with telmisartan at the concentration of 10(-7), 10(-6) and 10(-5) mol/L stimulated 1.5-, 2.7- and 4.6-fold increase in the ACE2 protein expression, as well as 1.2-, 2.3- and 4.5-fold increase in its gene expression, respectively. After treatment of HUVECs with telmisartan for 6, 12, and 24 hours at the concentration of 10(-6) mol/L, the ACE2 protein expression increased 1.6-, 2.7- and 4.2-fold, and its gene expression increased 1.3-, 2.3- and 4.0-fold, respectively. Compared with control and telmisartan groups, PD123319 had no effect on both protein and gene expression of ACE2 (P>0.05). CONCLUSION: Telmisartan up-regulates the protein and gene expression of ACE2 in HUVECs in a concentration and time dependent manner. This effect may be mediated via its specific pathway.