Rosuvastatin enhances angiogenesis via eNOS-dependent mobilization of endothelial progenitor cells.

Circulating endothelial progenitor cells (circEPCs) of bone marrow (BM) origin contribute to postnatal neovascularization and represent a potential therapeutic target for ischemic disease. Statins are beneficial for ischemia disease and have been implicated to increase neovascularization via mechanisms independent of lipid lowering. However, the effect of Statins on EPC function is not completely understood. Here we sought to investigate the effects of Rosuvastatin (Ros) on EPC mobilization and EPC-mediated neovascularization during ischemic injury. In a mouse model of surgically-induced hindlimb ischemia (HLI), treatment of mice with low dose (0.1 mg/kg) but not high dose (5 mg/kg) significantly increased capillary density and accelerated blood flow recovery, as compared to saline-treated group. When HLI was induced in mice that had received Tie2/LacZ BM transplantation, Ros treatment led a significantly larger amount of endothelial cells (ECs) of BM origin incorporated at ischemic sites than saline. After treatment of mice with a single low dose of Ros, circEPCs significantly increased from 2 h, peaked at 4 h, declined until 8 h. In a growth-factor reduced Matrigel plug-in assay, Ros treatment for 5 d induced endothelial lineage differentiation in vivo. Interestingly, the enhanced circEPCs and post-HLI neovascularization stimulated by Ros were blunted in mice deficient in endothelial nitric oxide synthase (eNOS), and Ros increased p-Akt/p-eNOS levels in EPCs in vitro, indicating these effects of Ros are dependent on eNOS activity. We conclude that Ros increases circEPCs and promotes their de novo differentiation through eNOS pathway.

18ß-Glycyrrhetinic acid potently inhibits Kv1.3 potassium channels and T cell activation in human Jurkat T cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Licorice has been extensively used in traditional medicines for treatment of many diseases, including inflammations and immunological disorders. Recent studies have shown that the anti-inflammatory and immunomodulation activities of licorice have been attributed to its active component, glycyrretinic acid (GA). GA consists of two isoforms, 18α- and 18ß-. However, its mechanism remains poorly understood. AIM OF THE STUDY: We compared the effects of two isoforms on Kv1.3 channels in Jurkat T cells and further characterized the inhibition of Kv1.3 channels by 18ß-GA in CHO cells. In addition, we examined the effects of 18ß-GA on Kv1.3 gene expression, Ca(2+) influx, proliferation, as well as IL-2 production in Jurkat T cells. MATERIALS AND METHODS: Whole-cell patch-clamp technique was applied to record Kv1.3 currents in Jurkat T or CHO cells. Real-time PCR and Western blotting were used to detect gene expression. Fluo-4, CCK-8 kit and ELISA kit were used to measure Ca(2+) influx, proliferation, and IL-2 secretion in Jurkat T cells, respectively. RESULTS: Superfusion of 18ß-GA (10-100 µM) blocked Kv1.3 currents in Jurkat T cells, while 18α-GA at the same concentration had no effect. The 18ß-GA induced inhibition had a voltage- and concentration-dependent manner with an IC50 of 23.9±1.5 µM at +40 mV in CHO cells. Furthermore, 18ß-GA significantly inhibited Kv1.3 gene expression. In addition, paralleling Kv1.3 inhibition, 18ß-GA also inhibited Ca(2+) influx, proliferation as well as IL-2 production in Jurkat T cells. CONCLUSION: 18ß-GA blocks Kv1.3 channels, which probably involves its anti-inflammatory and immunomodulation effects.

Protective effect of Astragalus polysaccharides on ATP binding cassette transporter A1 in THP-1 derived foam cells exposed to tumor necrosis factor-alpha.

Astragalus polysaccharide (APS), the main extract from the traditional Chinese medicinal herb Astragalus membranaceus, has been reported to benefit the treatment of immune-inflammatory diseases and metabolic disorders. In atherosclerotic plaques, proinflammatory cytokines exert adverse effects on lipids thereby aggravating atherosclerosis. Recent evidence shows that tumor necrosis factor-alpha (TNF-alpha) can down-regulate the expression of ATP-binding cassette transporter A1 (ABCA1), which plays a vital role in reverse cholesterol transport and determines the process of atherosclerosis. In the present study, the effects of APS on ABCA1 expression, cholesterol effluent rate and total cholesterol content of THP-1 derived foam cells exposed to TNF-alpha were investigated. Compared with the foam cells exposed to TNF-alpha, ABCA1 expression was promoted in the presence of APS. Consequently the cholesterol effluent rate increased and the total cholesterol content decreased significantly. TNF-alpha could enhance the activity of nuclear factor-kappa B (NF-kappaB) in the foam cells. This effect could be attenuated by APS. These findings suggest that APS could protect ABCA1 against the lesion of TNF-alpha in THP-1 derived foam cells, which may contribute to its antiatherosclerotic properties.

Qiliqiangxin regulates the balance between tumor necrosis factor-alpha and interleukin-10 and improves cardiac function in rats with myocardial infarction.

The study investigated the effects of traditional Chinese drug Qiliqiangxin on cardiac function and the expression of pro/anti-inflammatory cytokines TNF-alpha/IL-10 in rats with myocardial infarction (MI). Rats with MI were randomly divided into drug-treated group (MI-Q) and control group (MI-C) compared with sham-operated group (S). Rats in the MI-Q group were treated with crude drug of oral Qiliqiangxin 24h after operation at the dosage of 4g/kg/day for 4weeks, while in MI-C group and S group were treated with normal saline at the same time. Echocardiography and hemodynamic parameters, histopathologic changes and the expression of myocardial cytokines including TNF-alpha and IL-10 were assessed 4weeks after the drug therapy. The results indicated that rats of the MI-C group exhibited decreased cardiac function and increased ratio of TNF-alpha/IL-10 which principally secreted by myocardium compared with those of the S group and Qiliqiangxin treatment significantly improved cardiac function and histopathologic changes with down-regulated ratio of TNF-alpha/IL-10. These data suggests that Qiliqiangxin may improve cardiac function of rats with MI through regulation the balance between TNF-alpha and IL-10.

Blockade of the human ether-a-go-go-related gene potassium channel by ketanserin.

In the present study, we investigated the inhibitory action of ketanserin on wild-type (WT) and Y652 mutant human ether-a-go-go-related gene (HERG) potassium channels expressed in Xenopus oocytes and the effects of changing the channel molecular determinants characteristics on the blockade with and without ketanserin intervention using standard two-microelectrode voltage-clamp techniques. Point mutations were introduced into HERG gene (Y652A and Y652R) and subcloned into the pSP64 plasmid expression vector. Complementary RNAs for injection into oocytes were prepared with SP6 Cap-Scribe after linearization of the expression construct with EcoR I. Clampfit 9.2 software was employed for data collection and analysis. Origin 6.0 software was used to fit the data, calculate time constants and plot histograms. The results showed that ketanserin blocked WT HERG currents in voltage- and concentration-dependent manner and showed minimal tonic blockade of HERG current evaluated by the envelope of tails test. The IC50 value was (0.38+/-0.04) micromol/L for WT HERG potassium channel. The peaks of the I-V relationship for HERG channel suggested a negative shift in the voltage-dependence of activation after using ketanserin, whose midpoint of activation values (V1/2) were (-16.59+/-1.01) mV (control) vs (-20.59+/-0.87) mV (ketanserin) at 0.1 micromol/L, (-22.39+/-0.94) mV at 1 micromol/L, (-23.51+/-0.91) mV at 10 micromol/L, respectively (P<0.05, n=6). Characteristics of blockade were consistent with an open-state channel blockade, because the extent and rate of onset of blockade was voltage-dependent, increasing at more potentials even in the condition of leftward shift of activation curve. Meanwhile, in the different depolarization duration, the fractional blockade of end-pulse step current and peak tail current at 100 ms duration was significantly lower than that at 400 ms and 700 ms, which indicated that following the channel activation fractional blockade was enhanced by the activated channels. Ketanserin could also modulate the inactivation of HERG channel, which shifted the voltage-dependence of WT HERG channel inactivation curve from (-51.71+/-2.15) mV to (-80.76+/-14.98) mV (P<0.05, n=4). The S6 mutation, Y652A and Y652R, significantly attenuated the blockade by ketanserin. The IC50 value were (27.13+/-9.40) micromol/L and (20.20+/-2.80) micromol/L, respectively, increased by approximately 72-fold for Y652A and 53-fold for Y652R compared to that of WT HERG channel blockade [(0.38+/-0.04) micromol/L]. However, between the inhibitory effects of Y652A and Y652R, there was no significant difference. In conclusion, ketanserin blocks WT HERG currents in voltage- and concentration-dependent manner and preferentially blocks open-state HERG channels. Tyr-652 is one of the critical residues in the ketanserin-binding sites.

[Folate reduces monocyte chemoattractant protein-1 expression in rats with hyperhomocysteinemia].

OBJECTIVE: To investigate effects of supplementation of folate on the expression of monocyte chemoattractant protein-1 (MCP-1) in aortic endothelium and release from peripheral blood mononuclear cells (PBMC) in rats with hyperhomocysteinemia induced by ingestion of excess methionine. METHODS: Thirty male SD rats were randomly divided into 3 groups (n = 10 for each group): control group (Control), high homocysteinemia group (Hhcy), and folate supplementation group (FA). They were fed with nomal diet, normal diet enriched by 1.7% methionine, and normal diet plus 1.7% methionine and 0.006% folate, respectively, for 45 days. The levels of total plasma homocysteine (Thcy) were measured by high performance liquid chromatography and the concentrations of chemokine MCP-1 released from PBMC stimulated by oxidized low density lipoprotein were detected by enzyme immunoassays. The expression of MCP-1 on aortas of rats was detected by immunohistochemistry and Western blot. RESULTS: A high methionine diet for 45 days induced hyperhomocysteinemia. Folate supplementation to high-methionine diet significantly decreased plasma Thcy levels (P < 0.01). The expression of MCP-1 in aortic endothelium and the levels of MCP-1 released from PBMC stimulated by oxidized low density lipoprotein were significantly higher in rats of Hhcy group than in rats of control group (P < 0.05, P < 0.01). During supplementation of folate, normalization of Thcy levels was accompanied by a marked reduction of MCP-1 expression in aortic endothelium and by a significant decrease of MCP-1 released from PBMC stimulated by oxidized low density lipoprotein (P < 0.05, P < 0.01). CONCLUSION: Folate supplementation can prevent an elevation of homocysteine levels in the blood and decrease the expression MCP-1 in aortic endothelium and release of MCP-1 from PBMC in rats with hyperhomocysteinemia.