Anthelmintics nitazoxanide protects against experimental hyperlipidemia and hepatic steatosis in hamsters and mice

Lipid metabolism disorders contribute to hyperlipidemia and hepatic steatosis. It is ideal to develop drugs simultaneous improving both hyperlipidemia and hepatic steatosis. Nitazoxanide is an FDA-approved oral antiprotozoal drug with excellent pharmacokinetic and safety profile. We found that nitazoxanide and its metabolite tizoxanide induced mild mitochondrial uncoupling and subsequently activated AMPK in HepG2 cells. Gavage administration of nitazoxanide inhibited high-fat diet (HFD)-induced increases of liver weight, blood and liver lipids, and ameliorated HFD-induced renal lipid accumulation in hamsters. Nitazoxanide significantly improved HFD-induced histopathologic changes of hamster livers. In the hamsters with pre-existing hyperlipidemia and hepatic steatosis, nitazoxanide also showed therapeutic effect. Gavage administration of nitazoxanide improved HFD-induced hepatic steatosis in C57BL/6J mice and western diet (WD)-induced hepatic steatosis in Apoe -/- mice. The present study suggests that repurposing nitazoxanide as a drug for hyperlipidemia and hepatic steatosis treatment is promising.

Mitochondrial uncoupler BAM15 inhibits artery constriction and potently activates AMPK in vascular smooth muscle cells

Our previous studies found that mitochondrial uncouplers CCCP and niclosamide inhibited artery constriction and the mechanism involved AMPK activation in vascular smooth muscle cells. BAM15 is a novel type of mitochondrial uncoupler. The aim of the present study is to identify the vasoactivity of BAM15 and characterize the BAM15-induced AMPK activation in vascular smooth muscle cells (A10 cells). BAM15 relaxed phenylephrine (PE)-induced constricted rat mesenteric arteries with intact and denuded endothelium. Pretreatment with BAM15 inhibited PE-induced constriction of rat mesenteric arteries with intact and denuded endothelium. BAM15, CCCP, and niclosamide had the comparable IC value of vasorelaxation in PE-induced constriction of rat mesenteric arteries. BAM15 was less cytotoxic in A10 cells compared with CCCP and niclosamide. BAM15 depolarized mitochondrial membrane potential, induced mitochondrial fission, increased mitochondrial ROS production, and increased mitochondrial oxygen consumption rate in A10 cells. BAM15 potently activated AMPK in A10 cells and the efficacy of BAM15 was stronger than that of CCCP, niclosamide, and AMPK positive activators metformin and AICAR. In conclusion, BAM15 activates AMPK in vascular smooth muscle cells with higher potency than that of CCCP, niclosamide and the known AMPK activators metformin and AICAR. The present work indicates that BAM15 is a potent AMPK activator.

Arterial relaxation is coupled to inhibition of mitochondrial fission in arterial smooth muscle cells: comparison of vasorelaxant effects of verapamil and phentolamine

Mitochondria are morphologically dynamic organelles which undergo fission and fusion processes. Our previous study found that arterial constriction was always accompanied by increased mitochondrial fission in smooth muscle cells, whereas inhibition of mitochondrial fission in smooth muscle cells was associated with arterial relaxation. Here, we used the typical vasorelaxants, verapamil and phentolamine, to further confirm the coupling between arterial constriction and mitochondrial fission in rat aorta. Results showed that phentolamine but not verapamil induced vasorelaxation in phenylephrine (PE)-induced rat thoracic aorta constriction. Verapamil, but not phentolamine, induced vasorelaxation in high K(KPSS)-induced rat thoracic aorta constriction. Pre-treatment with phentolamine prevented PE- but not KPSS-induced aorta constriction and pre-treatment with verapamil prevented both PE- and KPSS-induced aorta constriction. Transmission electron microscopy (TEM) results showed that verapamil but not phentolamine inhibited KPSS-induced excessive mitochondrial fission in aortic smooth muscle cells, and verapamil prevented both PE- and KPSS-induced excessive mitochondrial fission in aortic smooth muscle cells. Verapamil inhibited KPSS-induced excessive mitochondrial fission in cultured vascular smooth muscle cells (A10). These results further demonstrate that arterial relaxation is coupled to inhibition of mitochondrial fission in arterial smooth muscle cells.

Mitochondrial uncoupler triclosan induces vasorelaxation of rat arteries

Our previous studies found that mitochondrial uncouplers induced vasodilation. Triclosan, the broad spectrum antibacterial agent, is the active ingredient in soaps and toothpastes. It was reported that triclosan induced mitochondrial uncoupling, so we aim to investigate the effects of triclosan on vascular function of rat mesenteric arteries and aorta. The isometric tension of rat mesenteric artery and thoracic aorta was recorded by multi-wire myograph system. The cytosolic [Ca], mitochondrial reactive oxygen species (mitoROS), and mitochondrial membrane potential of smooth muscle cells (A10 cells) were measured using laser scanning confocal microscopy. Triclosan treatment relaxed phenylephrine (PE)- and high K(KPSS)-induced constriction, and pre-treatment with triclosan inhibited PE- and KPSS-induced constriction of rat mesenteric arteries. In rat thoracic aorta, triclosan also relaxed PE- and KPSS-induced constriction. Triclosan induces vasorelaxation without involving Kchannel activation in smooth muscle cells of arteries. Triclosan treatment increased cytosolic [Ca], mitochondrial ROS production and depolarized mitochondrial membrane potential in A10 cells. In conclusion, triclosan induces mitochondrial uncoupling in vascular smooth muscle cells and relaxes the constricted rat mesenteric arteries and aorta of rats. The present results suggest that triclosan would indicate vasodilation effect if absorbed excessively.

DMH1 (4-6-(4-isopropoxyphenyl)pyrazolo1,5-apyrimidin-3-ylquinoline) inhibits chemotherapeutic drug-induced autophagy

Our previous work found that DMH1 (4-[6-(4-isopropoxyphenyl)pyrazolo [1,5-a]pyrimidin-3-yl]quinoline) was a novel autophagy inhibitor. Here, we aimed to investigate the effects of DMH1 on chemotherapeutic drug-induced autophagy as well as the efficacy of chemotherapeutic drugs in different cancer cells. We found that DMH1 inhibited tamoxifen- and cispcis-diaminedichloroplatinum (II) (CDDP)-induced autophagy responses in MCF-7 and HeLa cells, and potentiated the anti-tumor activity of tamoxifen and CDDP for both cells. DMH1 inhibited 5-fluorouracil (5-FU)-induced autophagy responses in MCF-7 and HeLa cells, but did not affect the anti-tumor activity of 5-FU for these two cell lines. DMH1 itself did not induce cell death in MCF-7 and HeLa cells, but inhibited the proliferation of these cells. In conclusion, DMH1 inhibits chemotherapeutic drug-induced autophagy response and the enhancement of efficacy of chemotherapeutic drugs by DMH1 is dependent on the cell sensitivity to drugs.

Basic research and application of microRNA--a novel target for regulating cardiac arrhythmias / 药学学报

Translational medicine is a novel concept about combination of basic research and clinical application. The aim of translational medicine is to realize the translation of basic research into clinical practice. microRNAs (miRNAs) are non-coding single-stranded RNAs with 21-25 nucleotides in length as newly discovered factors in regulating gene expression. Recently, the key regulatory role of miRNA in the cardiovascular system has been elucidated and amount of remarkable results has been achieved, particularly in the regulation of cardiac arrhythmias. A series of studies demonstrate that miRNAs are involved in the regulation of expression of a variety of proteins associated with cardiac electrical activity, and are the potential targets of occurrence of cardiac arrhythmias and anti-arrhythmic drugs. miRNAs as a therapeutic target regulate the stability of mRNAs of target genes or play an inhibitory role in the translation process. Stability of the corresponding miRNA expression levels in the target organ may be a new approach for the disease therapy. Regarding the dysfunction of miRNA, we employed miRNA re-expression strategy and anti-miRNA strategy to correct target protein function and provide a new entry for the therapy of arrhythmia. With the technology of miRNA mimics and antagomirs, miRNAs are expected to treat various cardiovascular diseases and will provide a fresh impetus to achieve transform medicine.

Integration: a method for evaluating voltage-dependent transient outward potassium currents in pharmacology / 中国药理学与毒理学杂志

AIM To evaluate the integration method for analysis of voltage-dependent Ca2+-independent transient outward K+ currents (Ito) in pharmacology. METHODSThe inactivation phases of Ito were best fitted by the sum of two or three exponentials equations. The area under the raw current curves (AUC) was obtained by the integration of exponential equations. The AUC normalized to the cell capacitance represented the net K+ charge flow during any depolarized duration and was as the index for comparison. Calcineurin overexpression transgenic (TG) mice showed downregulation of Ito. These data were tested by the integration method. RESULTS AUC obtained from three or two exponentials fittings was calculated as: AUC=A1τ1+A2τ2+A3τ3+A0t-A1τ1e-t/τ1-A2τ2e-t/τ2-A3τ3e-t/τ3 or AUC=A1τ1+A2τ2+A0t-A1τ1e-t/τ1-A2τ2e-t/τ2. The 50% and 90% action potential duration (APD50, APD90) in ventricular myocytes of mice are about 10 ms and 30 ms, respectively. AUC at 10 ms (AUC50, AUC of 50% APD) and 30 ms (AUC90, AUC of 90% APD) in left ventricle cardiomyocytes of wild type (WT) and TG mice were normalized to the cell capacitance. The normalized AUC50 and AUC90 of WT group were significantly more than those of TG group, which was consistent to the prolongation of APD in TG mice and the previous published results(downregulation of components of Ito in TG mice). CONCLUSION The integration method was an ideal way for analysis of transient outward K+ currents in pharmacology.

Arsenic trioxide-induced HeLa cell death is partially prevented by K + channel blockers / 药学学报

Aim To investigate the effects of K + channel blockers on arsenic trioxide-induced HeLa cell death. Methods Viability of HeLa cells was assessed by mitochondrial dehydrogenase activity using colorimetric MTT assay and the voltage-dependent K+ currents were recorded by using patch-clamp rest living cells after As2 O3 24 h-incubation showed significant increase of K + currents densities. At + 80mV, the densities of K+ currents (61 ± 18) pA/10 pF (n = 8) in As2O3 24 h-incubation group were significantly more than that in the control group (38 ± 10) pA/10 pF (n = 8, P ＜ 0. 05 ). The HeLa cells were prevented partially from As2 O3-induced cell death by co-application for 24 h with typical voltageeffects on HeLa cells. Conclusion Chronic treatment with As2 O3 increased voltage-dependent K+currents in HeLa cells and the cell death induced by As2O3 was reduced partially by voltage-dependent K +channel blockers, 4-aminopyridine or tetraethylammonium.

Effects of 4-aminopyridine on the gastrointestinal function of murine / 中国药理学通报

Aim To investigate the effects of 4-aminopyridine (4-AP),K+ channel blocker, on the gastrointestinal function of murine. Methods Charcoal suspension was used to detect the effects of 4-AP on gastrointestinal motility of mice in vivo, contraction of isolated fundus longitudinal strips and duodenum of rats were studied in vitro,gastric acid secretion was measured by Gastric Secretion Test. Results 4-AP(5 mg?kg -1,ig)inhibited the gastrointestinal motility of mice. 4-AP(5 mmol?L -1) increased the maximum contractive force and minimum relaxation force, decreased the amplitude and frequency of the isolated duodenum peristaltic contraction. 4-AP(2.5 mg?kg -1,ip) significantly enhanced gastric acid secretion of rats. Conclusion 4-AP inhibited gastrointestinal motility and enhanced gastric acid secretion in murine.

Effects of chlorzoxazone on HepG2 tumor cells / 中国药理学通报

Aim To investigate effects of chlorzoxazone on survival and apoptosis of HepG2 cells.Methods The necrosis of HepG2 cells was evaluated by measurement of LDH release.The effects of chlorzoxazone on survival of HepG2 cells were assayed by MTT dyereduction.The effects of chlorzoxazone on cell apoptosis was analyzed by TUNEL method.The ultrastructure of HepG2 cells was observed by transmission electron microscope.Results Chlorzoxazone at concentrations of 100～500 ?mol?L-1 inhibited survival ratios of HepG2 cells in a dose-dependent manner significantly.Typical apoptotic changes were observed in HepG2 cells under the fluorescence microscope and transmission electron microscope.Apoptosis of HepG2 cells was induced after treatment of chlorzoxazone at concentrations from 100 ?mol?L-1 to 500 ?mol?L-1 for 48h,which showed obvious concentration-effect relationship.The apoptotic ratios of HepG2 cells were also increased when chlorzoxazone(100,200,300 and 500 ?mol?L-1) was treated for 24,48 and 72 h,which showed obvious time-effect relationship.Conclusion Chlorzoxazone inhibited HepG2 cells survival and induced cell apoptosis.