Yiqun Tang

Antioxidant and cardioprotective effects of Danshensu (3-(3, 4-dihydroxyphenyl)-2-hydroxy-propanoic acid from Salvia miltiorrhiza) on isoproterenol-induced myocardial hypertrophy in rats.

Myocardial hypertrophy has been linked to the development of a variety of cardiovascular diseases, and is a risk factor for myocardial ischemia, arrhythmias, and sudden cardiac death. The objective of the present study was to evaluate the cardioprotective effects of Danshensu (DSS), a water-soluble active component of Danshen, on cardiac hypertrophy in rats. We are the first to report that DSS reversed Cx43 down-regulation in ventricular tissue. Cardiomyopathy in rats was produced using isoproterenol (Iso) treatment (2.5 mg/kg/d, s.c.) for seven days. DSS (3 and 10 mg/kg/d, i.p.) and Valsartan (Val) (10 mg/kg, i.g.) were administered on days 4-7 of Iso-treatment. Heart weight index, hemodynamic parameters, and ECG II parameters were monitored and recorded; protein expression of left ventricular connexin 43 (Cx43) and the activity of the redox system were assayed, and arrhythmias were produced using a coronary ligation/reperfusion procedure. The results demonstrated that DSS treatment significantly decreased heart weight/body weight (HW/BW) and left ventricular weight/body weight (LVW/BW) ratios. The protective role of DSS against Iso-induced myocardial hypertrophy was further confirmed using ECG. The incidences of ventricular tachycardia and ventricular fibrillation (VT, VF) and arrhythmic scores were higher in the model group and were suppressed by DSS. DSS decreased the serum and myocardium levels of creatine kinase, lactate dehydrogenase, and malondialdehyde (CK, LDH, and MDA) and increased serum activity of superoxide dismutase (SOD) in a dose-dependent manner. Cx43 expression in the left ventricle was down-regulated, and there was significant oxidative stress in this model of cardiomyopathy. DSS reversed the down-regulated Cx43 protein levels and showed potent anti-oxidative activities and cellular protection. These data demonstrate that DSS can prevent cardiac I/R injury and improve cardiac function in a rat model of hypertrophy, the effects partially resulting from antioxidants and the protection from Cx43 expression.

Design and bio-evaluation of indole derivatives as potent Kv1.5 inhibitors.

Atrial fibrillation (AF) is one of the common arrhythmias that threaten human health. Kv1.5 potassium channel is reported as an efficacious and safe target for the treatment of AF. In this paper, we designed and synthesized three series of compounds through modifying the lead compound RH01617 that was screened out by the pharmacophore model we reported earlier. All of the compounds were evaluated by the whole-patch lamp technology and most of them possessed potent inhibitory activities against Kv1.5. Compounds IIIi and IIIl were evaluated for the target selectivity as well as the pharmacodynamic effects in an isolated rat model. Due to the promising pharmacological behavior, compound IIIl deserves further pharmacodynamic and pharmacokinetic evaluations.

Molecular hybridization, synthesis, and biological evaluation of novel chroman I(Kr) and I(Ks) dual blockers.

The combination of I(Kr) and I(Ks) blockade could lead to synergistic and safe class III anti-arrhythmic effect with the enhanced efficacy and reduced risk. On the rationale of structural hybridization of azimilide and HMR-1556, a novel series of I(Kr) and I(Ks) dual blockers were designed, synthesized and evaluated in vitro. One compound, 3r (CPUY11018), deserves further evaluation for its potent anti-arrhythmic activity and favorable cardiovascular profile.

Discovery of 1-aryloxyethyl piperazine derivatives as Kv1.5 potassium channel inhibitors (part I).

Kv1.5 potassium channel is an efficacious and safe therapeutic target for the treatment of atrial fibrillation (AF), the most common arrhythmia that threatens human. Herein, by modifying the hit compound 7k from an in-house database, 48 derivatives were synthesized for the assay of their Kv1.5 inhibitory effects by whole cell patch clamp technique. Six compounds which showed better potency than the positive compound dronedarone were selected for the next evaluation of their drug-like properties. Compound 8 exhibited balanced solubility and permeability. It also showed acceptable pharmacodynamics profile with very low acute toxicity. Taking all these data into account, compound 8 can serve as a promising lead for the development of novel therapeutic agent for the treatment of AF.

The Multiple Ion Channel Blocker CPUY11018 Prevents Aconitine-Induced Arrhythmias

Strategy, Management and Health Policy Enabling Technology, Genomics, Proteomics Preclinical Research Preclinical Development Toxicology, Formulation Drug Delivery, Pharmacokinetics Clinical Development Phases I‐III Regulatory, Quality, Manufacturing Postmarketing Phase IV

AstragalosideIV against cardiac fibrosis by inhibiting TRPM7 channel

BACKGROUND Astragaloside Ⅳ (ASG-Ⅳ, (Fig. 1) is the most active component of Chinese sp. Astragalus membranaceus Bunge (Fabaceae) that has showed antioxidant, antiapoptotic and antiviral activities among others. It is reported to play an important role in cardiac fibrosis (CF), but the mechanism remains unclear. PURPOSE To investigate the mechanism of ASG-Ⅳ on inhibiting myocardial fibrosis induced by hypoxia. STUDY DESIGN We studied the relationship between anti-fibrotic effect of ASG-Ⅳ and transient receptor potential cation channel, subfamily M, member 7 (TRPM7) by in vivo and in vitro experiments. METHODS In vivo, CF was induced by subcutaneous isoproterenol (ISO) for 10 days. Rat hearts were resected for histological experiment and reverse transcription real-time quantitative poly merase chain reaction (RT-qPCR). In vitro, molecular and cellular biology technologies were used to confirm the anti-fibrosis effect underlying mechanism of ASG-Ⅳ. RESULTS Histological findings and the collagen volume fraction showed that ASG-Ⅳ decreased fibrosis in heart tissues. Hypoxia could stimulate the proliferation and differentiation of cardiac fibroblast which indicated that the degree of fibrosis was increased significantly. Anoxic treatment could also obviously up-regulate the expression of TRPM7 protein and current. ASG-Ⅳ groups showed the opposite results. Knock-down TRPM7 experiment further confirmed the role of TRPM7 channel in hypoxia-induced cardiac fibrosis. CONCLUSION Our results suggest that the inhibition of hypoxia-induced CF in vivo and in vitro by ASG-IV is associated with reduction of the expression of TRPM7. The moderate inhibition of the TRPM7 channel may be a new strategy for treating cardiac fibrosis.

Antiarrhythmic Efficacy of CPUY11018 Under Pathological Conditions

Preclinical Research

MicroRNA-135a inhibits cardiac fibrosis induced by isoproterenol via TRPM7 channel

BACKGROUND Cardiac fibrosis is a crucial factor of heart failure. It has been reported that several microRNAs (miRNAs, miRs) were involved in cardiac fibrosis, however, the role and possible regulatory mechanism of microRNA-135a (miR-135a) in cardiac fibrosis have not been investigated. Here, we explored the regulation mechanism of miR-135a on cardiac fibrosis. METHODS AND RESULTS In vitro, cardiac fibroblasts (CFs) from neonatal rats were treated by isoproterenol (ISO) at the final concentration of 10 μM for 24 h and miR-135a expression was decreased obviously. A miR-135a mimic inhibited CFs proliferation and differentiation by down-regulating transient receptor potential melastatin 7 (TRPM7) expression and current, whose effects were reversed by either the addition of miR-135a mimic or silencing TRPM7. In vivo, adult SD rat cardiac fibrosis was induced by subcutaneous administration of ISO (5 mg/kg/day) for 10 days. The expression of Collagen I, α-smooth muscle actin (α-SMA) and TRPM7 were up-regulated while miR-135a was down-regulated. In summary, our results illustrated that TRPM7 channel played an essential role in regulating fibrosis and that miR-135a protected against ISO-induced cardiac fibrosis via TRPM7 channel. CONCLUSION MiR-135a inhibits cardiac fibrosis via miR-135a- TRPM7-collagen production pathway.

Antiarrhythmic efficacy of CPUY102122, a multiple ion channel blocker, on rabbits with ischemia/reperfusion injury

BACKGROUND The antiarrhythmic potential of a novel multichannel blocker CPUY102122 (CY22) was investigated in the present study. METHODS The effect of CY22 on rapid delayed rectifier potassium channel current (IKr) was studied using whole-cell patch clamp techniques in Chinese Hamster Ovary cells stably expressing human Ether-à-go-go-Related Gene. We further evaluated the antioxidant effects of CY22 and demonstrated the reversal of connexin down-regulation in the development of cardiac ventricular arrhythmias, which was produced using coronary ligation/reperfusion in rabbits. CY22 and Amiodarone were administered 30min prior to the procedure. Next, electrocardiograms were recorded, protein expression of left ventricular Connexin43 (Cx43), non-phosphorylation-Cx43 (np-Cx43), Rac-1 and gp-91[phox] were assayed using Western blot analysis, microstructural changes in the myocardium were observed and redox system activity was assayed. RESULTS CY22 inhibited IKr in a concentration-dependent manner with IC50 value of 2.8±0.8μmol/L. CY22 treatment significantly decreased T-wave amplitude and QTc arrhythmic scores and ameliorated the shape of the infarcted myocardium compared to the model group. CY22 decreased the serum levels of creatine kinase, lactate dehydrogenase, and myocardial levels of malondialdehyde, as well as increased superoxide dismutase activity. Cx43 expression in the left ventricle was significantly increased by CY22 treatment, which significantly decreased np-43 expression, Rac-1 activity and gp-91[phox] protein expression. CONCLUSIONS These results indicated that CY22 has both antiarrhythmic and cardiovascular protective effects partly by blocking IKr, the production of antioxidants and protection of Cx43.

Discovery of Aroyl Piperazine Derivatives as I Kr & I Ks Dual Inhibitors for Cardiac Arrhythmia Treatment

Combined blockade of IKr and IKs potassium channels is considered to be a promising therapeutic strategy for arrhythmia. In this study, we designed and synthesized 15 derivatives through modifying the hit compound 7 that was discovered by screening in-house database by whole-patch clamp technique. All of the compounds were evaluated on CHO and HEK 293 cell lines stably expressing hERG (IKr) and hKCNQ1/KCNE1 (IKs) potassium channels, and half of them exhibited improved dual IKr and IKs inhibitory effects compared to the hit compound. Compounds 7a and 7b with potent dual inhibitory activities were selected for further in vivo evaluations. Due to the preferable pharmacological behaviors, compound 7a deserved further optimization as a promising lead compound.