ABSTRACT
Objective: To investigate the mechanisms of electroacupuncture (EA) at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6) in intervening diabetic gastroparesis (DGP) based on calcium-activated chloride channel. Methods: Forty Sprague-Dawley rats were randomly divided into four groups, including a normal control group (group A), a model group (group B), an EA group (group C) and a metoclopramide group (group D), with 10 rats in each group. A single intraperitoneal injection of 2％ streptozotocin (STZ) combined with 8-week high-glucose high-fat diet was used to establish a DGP rat model. After intervention, gastrointestinal propulsive rate was observed; the expression level of transmembrane protein 16A (TMEM16A) was examined by immunohistochemistry; the Ca2+ concentration in interstitial cells of Cajal (ICCs) was detected by immunofluorescence; and whole-cell patch-clamp technique was applied to detect the current intensity of calcium-activated chloride channel (ICaCC) in ICCs in gastric antrum. Results: After modeling, the blood glucose levels in group B, group C and group D were significantly increased compared with group A (all P<0.01); after intervention, compared with group B, the blood glucose levels in group C and group D were significantly decreased (P<0.05, P<0.01); the intra-group comparison of blood glucose level between after modeling and after intervention found significant difference only in group C (P<0.01). The gastrointestinal propulsive rates in group B, group C and group D were significantly different from that in group A (P<0.01 or P<0.05); the gastrointestinal propulsive rates were markedly higher in group C and group D than in group B (P<0.01, P<0.01). The expressions of TMEM16A in group B and group C were decreased compared with group A (P<0.01, P<0.05); the expressions of TMEM16A in group C and group D were increased compared with group B (P<0.01, P<0.05). The fluorescence intensity of Ca2+ was significantly lower in group B than in group A (P<0.01); the fluorescence intensity of Ca2+ was significantly higher in group C and group D than in group B (P<0.01, P<0.05). ICaCC in ICCs in group B was significantly decreased compared with group A; ICaCC in group C and group D were increased compared with group B. Conclusion: EA at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6) can significantly improve gastrointestinal motility in DGP rats by up-regulating the ICaCC in ICCs.
ABSTRACT
Vascular smooth muscle cell (VSMC) migration plays a critical role in the pathogenesis of many cardiovascular diseases. We recently showed that TMEM16A is involved in hypertension-induced cerebrovascular remodeling. However, it is unclear whether this effect is related to the regulation of VSMC migration. Here, we investigated whether and how TMEM16A contributes to migration in basilar artery smooth muscle cells (BASMCs). We observed that AngII increased the migration of cultured BASMCs, which was markedly inhibited by overexpression of TMEM16A. TMEM16A overexpression inhibited AngII-induced RhoA/ROCK2 activation, and myosin light chain phosphatase (MLCP) and myosin light chain (MLC20) phosphorylation. But AngII-induced myosin light chain kinase (MLCK) activation was not affected by TMEM16A. Furthermore, a suppressed activation of integrin
ABSTRACT
Epilepsy is one of the most common chronic neurological diseases, which results from diverse etiologies, and its mechanism is very complicated.Ion channel gene mutation is a common genetic cause of epilepsy.Voltage-gated chloride channels (ClCs) can change the chloride ion concentration and electric potential difference across the plasma membrane, and thereby regulate the electrical excitability of neurons.CLCN-1, CLCN-2, CLCN-3, CLCN-4 and CLCN-6 are reported to be associated with epilepsy, which could increase susceptibility to epilepsy or cause seizures.This review is focused on recent advances in ClCs and epilepsy.
ABSTRACT
Objective To study the effect and mechanisms of chloride channel blocker 5-Nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) on thansforming growth factor β1 (TGF-β1) induced human conjunctival fibroblasts (HConF) fibrosis.Methods Cell counting kit (CCK-8) was used to screen out the optimal TGF-β1 treatment time and the optimal NPPB concentration.The cells were divided into control group,TGF-β1 treatment group and TGF-β1+NPPB group.Cell proliferation and cell cycle were detected by CCK-8 and flow cytometer,respectively.Cell migration ability were observed by scratch and transwell migration assays.Western blot and Real time-PCR were used to detect the expression of collagen Ⅰ (COL-Ⅰ),fibronectin (FN) and α-smooth muscle actin (α-SMA).The phosphorylation level of PI3K and Akt were measured by Western blot.Results TGF-β1 promotes cell proliferation in a time-dependent manner.There was no statistically significant difference in A values between 48 hours and 72 hours after TGF-β1 treatment (P =0.064).Forty-eight hours was selected as the most appropriate time for TGF-β1 treatment.NPPB inhibited HConF cell proliferation in a concentration-dependent manner.Compared with the control group,the proliferation A values of cells in the 50 mol/L and 100 mol/L NPPB groups were significantly reduced (P =0.020,0.000),and 100 mol/L was selected as the optimal concentration of NPPB.The cell proliferation A value,migration area and migration cell number of TGF-β1 +NPPB group were significantly lower than those of TGF-β1 treatment group (all at P＜0.05).Compared with the control group and TGF-β1 +NPPB group,the proportion of G1 phase cells in the TGF-β1 treatment group was reduced,and the proportion of cells in the S phase and G2/M phase were increased,with statistically significant differences between them (all at P ＜ 0.05).The protein and mRNA expression of α-SMA,COL-Ⅰ and FN in the TGF-β1 treatment group were higher than those in the control group and TGF-β1+NPPB group,with statistically significant differences between them(all at P＜0.05);the ratios of p-PI3K/PI3K and p-Akt/Akt in the TGF-β1 treatment group were significantly higher than those in the control group and TGF-β1 +NPPB group,with statistically significant differences between them (all at P＜0.05).Conclusions NPPB may inhibit TGF-β1 induced HConF fibrosis process by inhibiting phosphorylation of PI3K and Akt.
ABSTRACT
Objective:To investigate the role of ClC-3 chloride channel in the proliferation of breast cancer cell line Mcf-7 treated with curcumin and its specific mechanism.Methods:MTT assay was used to detect the effect of chloride channel blocker (DIDS) and curcumin on Mcf-7 and human normal cell viability. Patch-clamp technique was used to determine the current density before and after drug treatment. Apoptosis assay by flow cytometry was performed for further examination of cell apoptosis.Results:Curcumin had toxicity on Mcf-7 and HUVEC cells and DIDS reduced the survival rate of Mcf-7 cells by inhibiting proliferation. Curcumin could activate the chloride ion current on MCF-7 cell membrane, which would be inhibited by DIDS. Finally, curcumin in low concentration combined with DIDS could significantly promote the MCF-7 cells apoptosis.Conclusions:Our results suggest that ClC-3 protein is involved in the regulation of curcumin induced proliferation inhibiting in breast cancer cells through inducing cell apoptosis. ClC-3 may be a potential target of tumor therapy.
ABSTRACT
Aim To study the effects of L-borneol on the chloride channel and cell volume of human umbili-cal vein endothelial cells (HUVECs). Methods Whole-cell patch-clamp technique was used to record chloride currents. The expression of ClC-3 protein was down-regulated by siRNA interference technique. The cell volume was measured by dynamic image analysis. Results 20 nmol·L-1L-borneol significantly activa-ted chloride current in HUVEC (79.59 ± 4.90) pA/pF, which could be inhibited by chloride channel blockers,NPPB and DIDS. The outward current inhib-itory rate of NPPB was (95.57 ± 2.57)%, while that of DIDS was (97.28 ± 6.36)%. The chloride current activated by L-borneol significantly decreased after the silence of ClC-3 (27.03 ± 3.89) pA/pF. Cell volume was markedly reduced by L-borneol (14.38 ± 1.58)%,which was inhibited after NPPB appliance. Conclusion L-borneol can activate ClC-3 chloride channel in HUVECs, which induces Cl- outflow then cell volume decrease.
ABSTRACT
Objective: To investigate the role of ClC-3 chloride channel in the proliferation of breast cancer cell line Mcf-7 treated with curcumin and its specific mechanism. Methods: MTT assay was used to detect the effect of chloride channel blocker (DIDS) and curcumin on Mcf-7 and human normal cell viability. Patch-clamp technique was used to determine the current density before and after drug treatment. Apoptosis assay by flow cytometry was performed for further examination of cell apoptosis. Results: Curcumin had toxicity on Mcf-7 and HUVEC cells and DIDS reduced the survival rate of Mcf-7 cells by inhibiting proliferation. Curcumin could activate the chloride ion current on MCF-7 cell membrane, which would be inhibited by DIDS. Finally, curcumin in low concentration combined with DIDS could significantly promote the MCF-7 cells apoptosis. Conclusions: Our results suggest that ClC-3 protein is involved in the regulation of curcumin induced proliferation inhibiting in breast cancer cells through inducing cell apoptosis. ClC-3 may be a potential target of tumor therapy.
ABSTRACT
OBJECTIVE@#To observe the effects of blocking and activating chloride channels on hemolysis induced by puerarin injection in rabbits and to investigate the roles of chloride channels in hemolytic reaction induced by puerarin injection.@*METHODS@#Rabbit erythrocyte suspension was incubated with different concentrations of puerarin injection(0.75, 1.5, 3, 6, 12 mg/ml) at 37C for 6 hours. The cell imaging system was employed to observe whether puerarin injection induced hemolysis. The hemolysis rate was detected by microplate reader and flow cytometry. Effects of activating and closing chloride channels on the hemolysis induced by puerarin injection were explored.@*RESULTS@#Puerarin injection could induce the hemolysis of rabbit erythrocytes . In the range of 1.5 mg/ml~12 mg/ml, puerarin injection could induce hemolysis in a concentration-dependent manner (=3, <0.01). The chloride channel blockers tamoxifen (20 μmol/L) and ATP (10 mmol/L) significantly inhibited the hemolysis induced by puerarin injection (=3~5, <0.01). Application of low concentration ATP (50 μmol/L) to activate the chloride channel significantly increased puerarin injection induced hemolysis (=4, <0.01).@*CONCLUSIONS@#The hemolytic effect of puerarin injection is dose-dependent , and the activation of chloride channel is closely related to the hemolysis induced by puerarin injection.
Subject(s)
Animals , Rabbits , Chloride Channels , Erythrocytes , Hemolysis , IsoflavonesABSTRACT
PURPOSE: Chloride channel-3 (ClC-3) is a member of the chloride channel family and plays a critical role in a variety of cellular activities. The aim of the present study is to explore the molecular mechanisms underlying the antitumor effect of silencing ClC-3 in breast cancer. METHODS: Human breast cancer cell lines MDA-MB-231 and MCF-7 were used in the experiments. Messenger RNA and protein expression were examined by quantitative real-time polymerase chain reaction and western blot analysis. Cell proliferation was measured by the bromodeoxyuridine method, and the cell cycle was evaluated using fluorescence-activated cell sorting. Protein interaction in cells was analyzed by co-immunoprecipitation. Tumor tissues were stained with hematoxylin-eosin and tumor burden was measured using the Metamorph software. RESULTS: Breast cancer tissues collected from patients showed an increase in ClC-3 expression. Knockdown of ClC-3 inhibited the secretion of insulin-like growth factor (IGF)-1, cell proliferation, and G1/S transition in breast cancer cells. In the mouse xenograft model of human breast carcinoma, tumor growth was significantly slower in animals injected with ClC-3-deficient cells compared with the growth of normal human breast cancer cells. In addition, silencing of ClC-3 attenuated the expression of proliferating cell nuclear antigen, Ki-67, cyclin D1, and cyclin E, as well as the activation of extracellular signal-regulated protein kinases (ERK) 1/2, both in vitro and in vivo. CONCLUSION: Together, our data suggest that upregulation of ClC-3 by IGF-1 contributes to cell proliferation and tumor growth in breast cancer, and ClC-3 deficiency suppresses cell proliferation and tumor growth via the IGF/IGF receptor/ERK pathway.
Subject(s)
Animals , Humans , Mice , Blotting, Western , Breast Neoplasms , Breast , Bromodeoxyuridine , Cell Cycle , Cell Line , Cell Proliferation , Chloride Channels , Cyclin D1 , Cyclin E , Cyclins , Flow Cytometry , Heterografts , Immunoprecipitation , In Vitro Techniques , Insulin-Like Growth Factor I , Methods , Proliferating Cell Nuclear Antigen , Protein Kinases , Real-Time Polymerase Chain Reaction , RNA, Messenger , Tumor Burden , Up-RegulationABSTRACT
Calcium-activated chloride channel (CaCC) is an anion channel, widely distributed in the human body, taking a part in cell functions including secretion, heart muscle repolarization, nerve signal transmission and several physiological activities. The anoctamin 1 (ANO1) protein is the molecular basis of CaCC and the modification of ANO1 protein will produce a variety of pharmacological effects, such as analgesia, treating dysentery and asthma, even tumor proliferation and migration inhibition. In the past decade, many methods in screening of ANO1 regulators have been developed. Although a series of the ANO1-based CaCC regulatory molecules have been identified, the pharmacological effects of these molecules are not consistent. In this review, we introduce ANO1 protein regulators from many aspects including bio-test methods, structure-activity relationships, and the potential applications.
ABSTRACT
To foster communication and interactions amongst international scholars and scientists in the field of ion channel research, the 6th International Ion Channel Conference (IICC-2017) was held between June 23-27, 2017 in the eastern coastal city of Qingdao, China. The meeting consisted of 450 attendees and 130 speakers and poster presenters. The program consisted of research progress, new findings and ongoing studies that were focused on (1) Ion channel structure and function; (2) Ion channel physiology and human diseases; (3) Ion channels as targets for drug discovery; (4) Technological advances in ion channel research. An insightful overview was presented on the structure and function of the mechanotransduction channelNOMPC (No mechanoreceptor potential C), a member of the transient receptor potential (TRP) channel family. Recent studies on Transmembrane protein 16 or Anoctamin-1 (TMEM16A, a member of the calcium-activated chloride channel [CaCC] family) were summarized as well. In addition, topics for ion channel regulation, homeostatic feedback and brain disorders were thoroughly discussed. The presentations at the IICC-2017 offer new insights into our understanding of ion channel structures and functions, and ion channels as targets for drug discovery.
ABSTRACT
Cystic fibrosis transmembrane conductance regulator(CFTR)is an ATP-gated,cAMP-dependent chloride channel. The basic biophysical and pathological functions of CFTR are related with the secretion of chloride ion in epithelial cells and tissues. Mutations in CFTR cause cystic fibrosis(CF),which is a rare but fatal autosomal recessive inheritant disease ,mainly affecting glan?dular epithelial function in respiratory tract ,intestinal and reproductive system. New drugs targeting human CFTR gene mutations have been developed to significantly prolong lifeand improve respiratory symptoms of CF patients. Recent evidence suggested that CFTR plays a functional role in vasoconstriction and the formation of myocardial action potential. As a channel protein ,CFTR may al?so functions as a multiprotein/channel complex ,which has been demonstrated in the development of cardiovascular diseases such as myocardial ischemia and pulmonary hypertension.
ABSTRACT
Volume regulated chloride channel (VRCC) enhances cell proliferation through PI3K/Akt signal pathway ,and inhibits cell apoptosis through mitochondrial pathway in vascular smooth muscle cells ,and accelerates the process of atherosclerosis through JNK/p38 MAPK signal pathway,resulting in increasing SR-A expression and ox-LDL uptake. Cerebrovascular remodeling is mediated by VRCC. This effect of VRCC on remodeling is related to accelerating cell proliferation ,migration and accumulation of. extracellular matrix. As to the molecular identification of VRCC ,it is very complex. VRCC is diversity in various cells or tissues , rather than a single ubiquitous channel,VRCC may be contain variedcell type-or tissue-specific subunitcompositions. ClC-3 volume regulated Cl-channel is regulated by both integrin-Src and Rho/RhA-Rock signal pathways.
ABSTRACT
Myotonia congenita (MC) is a genetic disease that displays impaired relaxation of skeletal muscle and muscle hypertrophy. This disease is mainly caused by mutations of CLCN1 that encodes human skeletal muscle chloride channel (CLC-1). CLC-1 is a voltage gated chloride channel that activates upon depolarizing potentials and play a major role in stabilization of resting membrane potentials in skeletal muscle. In this study, we report 4 unrelated Korean patients diagnosed with myotonia congenita and their clinical features. Sequence analysis of all coding regions of the patients was performed and mutation, R47W and A298T, was commonly identified. The patients commonly displayed transient muscle weakness and only one patient was diagnosed with autosomal dominant type of myotonia congenita. To investigate the pathological role of the mutation, electrophysiological analysis was also performed in HEK 293 cells transiently expressing homo- or heterodimeric mutant channels. The mutant channels displayed reduced chloride current density and altered channel gating. However, the effect of A298T on channel gating was reduced with the presence of R47W in the same allele. This analysis suggests that impaired CLC-1 channel function can cause myotonia congenita and that R47W has a protective effect on A298T in relation to channel gating. Our results provide clinical features of Korean myotonia congenita patients who have the heterozygous mutation and reveal underlying pathophyological consequences of the mutants by taking electrophysiological approach.
Subject(s)
Humans , Alleles , Chloride Channels , Clinical Coding , Electrophysiology , HEK293 Cells , Hypertrophy , Membrane Potentials , Muscle Weakness , Muscle, Skeletal , Myotonia Congenita , Myotonia , Relaxation , Sequence AnalysisABSTRACT
Neuronal firing patterns and frequencies determine the nature of encoded information of the neurons. Here we discuss the molecular identity and cellular mechanisms of spike-frequency adaptation in central nervous system (CNS) neurons. Calcium-activated potassium (K(Ca)) channels such as BK(Ca) and SK(Ca) channels have long been known to be important mediators of spike adaptation via generation of a large afterhyperpolarization when neurons are hyper-activated. However, it has been shown that a strong hyperpolarization via these KCa channels would cease action potential generation rather than reducing the frequency of spike generation. In some types of neurons, the strong hyperpolarization is followed by oscillatory activity in these neurons. Recently, spike-frequency adaptation in thalamocortical (TC) and CA1 hippocampal neurons is shown to be mediated by the Ca²⁺-activated Cl- channel (CACC), anoctamin-2 (ANO2). Knockdown of ANO2 in these neurons results in significantly reduced spike-frequency adaptation accompanied by increased number of spikes without shifting the firing mode, which suggests that ANO2 mediates a genuine form of spike adaptation, finely tuning the frequency of spikes in these neurons. Based on the finding of a broad expression of this new class of CACC in the brain, it can be proposed that the ANO2-mediated spike-frequency adaptation may be a general mechanism to control information transmission in the CNS neurons.
Subject(s)
Action Potentials , Brain , Central Nervous System , Fires , Neurons , Potassium , Potassium Channels, Calcium-ActivatedABSTRACT
Objective To investigate the effect of channel density on the gating properties of Anoctamin 1(Ano1,TMEM16A)Ca2+?activated chlo?ride channel. Methods Ano1 expression plasmids were transiently transfected into HEK293 cells. High density and low density of Ano1 was ob?tained after expressing the protein for 24 h and 6 h,respectively. Electrophysiological recordings were performed in the whole?cell patch clamp con?figuration. The activation kinetics of current traces was fitted by exponentials. Results The current density was significantly higher in cells express?ing Ano1 for 24 h than those expressing Ano1 for 6 h(P0.05). Conclusion Our findings suggested that chan?nel density regulates the gating of Ano1. High channel density promotes activation of Ano1.
ABSTRACT
Objective:To investigate the induction effect of NPPB,a chloride channel blocker,on the apoptosis of human glioma SHG-44 cells,and to explore its mechanism. Methods:The SHG-44 cells were cultured in vitro and divided into control group and NPPB groups (50,100,200 μmol· L-1 ).The cell viability was detected by MTT assay.The apoptotic rates were detected by flow cytometry.The expression levels of Bax, Bcl-2 and caspase-3 were detected by immunohistochemical analysis and Western blotting method.Results:Compared with control group,the cell viabilities of SHG-44 cells in 100 and 200 μmol·L-1 NPPB groups after treated for 24 and 48 h were decreased significantly (P < 0.01).The results of flow cytometry showed that the apoptotic rates of SHG-44 cells in 100 and 200 μmol·L-1 NPPB groups were 24.64% and 41.85%,and they were higher than that in control group (4.17%) (P <0. 01).The immunohistochemical analysis and Western blotting results showed that the expression levels of caspase-3 and Bax proteins in SHG-44 cells in 100 μmol · L-1 NPPB group were increased (P < 0.05 or P < 0. 01 ), and the expression level of Bcl-2 protein was decreased (P < 0.05 ). Conclusion:NPPB could induce the apoptosis of human glioma SHG-44 cells by the down-regulation of the expression of Bcl-2 and the up-regulation of the expression of Bax,and the activation of caspase-3.
ABSTRACT
Aim To investigate the effect of gelsemium alkaloids on chloride channels and cell volume in he-patic carcinoma cells. Methods The time-lapse live cell imaging and whole-cell patch clamp techniques were used respectively to detect the volume changes and currents induced by gelsemium alkaloids in HepG2 cells. Results It was found that the cell volume was decreased by (12. 48 ± 2. 2) % (P<0. 01) when ex-posed to gelsemium alkaloids for 50 min and this phe-nomenon could be inhibited by the chloride channel blocker tamoxifen. It was shown by whole-cell patch clamping that a chloride current could be evoked by extracellular application of gelsemium alkaloids ( 2μmol·L-1 ) . The current was outward-rectified with-out obvious voltage- and time-dependent inactivation. The reversal potential of the current was ( -3. 21 ± 0. 67) mV ,which was close to the equilibrium poten-tial of chloride. The extracellular application of the chloride blockers, tamoxifen and 5-notro-2-(3-phenyl-propylamino)benzoic acid (NPPB), and 47% hyper-tonic solution inhibited the current significantly ( P <0. 01 ) . Conclusion Gelsemium alkaloids could acti-vate chloride channels and induce a volume decrease ( named apoptotic volume decrease, AVD) , and these effect could be inhibited by chloride channel blockers. The results suggest that the chloride channel can be one of the targets of gelsemium alkaloids in their anti-cancer action.
ABSTRACT
Aim To establish a hepatic carcinoma cell line with stable voltage-gated chloride channel 3 ( ClC-3 ) gene silencing through the lentivirus-mediated short-hairpin RNA ( shRNA ) method and investigate the effects of gene silencing on invasion and migration. Methods Three lentiviral vectors coding shRNA tar-geting ClC-3 gene were constructed, the recombinant plasmids were packaged into mature lentivirus by 293FT cells, and then the lentiviruses were harvested, concentrated and titrated. MHCC97H cells were infec-ted with the recombinant lentiviruses and then were se-lected to obtain cell lines stably expressing ClC-3 shR-NA. The efficiency of ClC-3 mRNA and protein ex-pression interference were determined by real-time flu-orescence quantitative PCR and Western blot, respec-tively. The effects of ClC-3 gene interference on inva-sion and migration of MHCC97 H cells were performed by Transwell chamber assays with or without Matrigel and cell scratch assay. Results The recombinant lentiviral vectors were successfully constructed and four lentiviruses were acquired after packaged by 293 FT cells. One negative control cell line and three cell lines with ClC-3 gene interference ( MHCC97 H/shClC-3-1 , shClC-3-2 and shClC-3-3 ) were successfully construc-ted after MHCC97 H cells were infected with lentivirus-es. The expression level of ClC-3 mRNA and protein in three ClC-3-silenced cells were obviously lower than the negative control cells ( P <0. 01 ) , MHCC97 H/shClC-3-2 cells showed the greatest inhibition of ClC-3 mRNA and protein expressions. As compared with the negative control cells, the ClC-3 gene interference sig-nificantly decreased invasion and migration of MH-CC97 H cells in vitro ( P <0. 01 ) . Conclusion The hepatic carcinoma cell lines with stable ClC-3 gene si-lencing were successfully established and the ClC-3 gene interference could significantly inhibit invasion and migration of MHCC97H cells.
ABSTRACT
Chloride channel CLC-5 is a voltage-dependent gated channel.The voltage-gated characteristic of CLC-5 is not only regulated by glutamate E211 and E268,but also by lysine K210.In proximal renal tubule,CLC-5 can interact with megalin protein,and adjust the reabsorption of albumin together.CLC-5 can also affect the activities of the sodium hydrogen exchanger isoform 3 in proximal renal tubule.CLCN5 gene mutations can lead to Dent disease,and recent studies have found some new pathogenic mutants of CLC-5,VS05G,L266V and G446A,and so on.CLCN5 can also mutate together with ORCL1,and then result in Dent disease.However,the regulatory mechanism of the voltage-gated channel,physiological functions and molecular mechanism,and Dent disease are still not entirely clear.In this paper,we will review these problems of CLC-5.