Background: The intestinal epithelium is an important barrier that depends on a complex mixture of proteins and these proteins comprise different intercellular junctions. The purpose of this study was to investigate ...Background: The intestinal epithelium is an important barrier that depends on a complex mixture of proteins and these proteins comprise different intercellular junctions. The purpose of this study was to investigate the postnatal and developmental changes in morphology, intercellular junctions and voltage-gated potassium(Kv) channels in the intestine of piglets during the suckling and post-weaning periods.Results: Samples of the small intestine were obtained from 1-, 7-, 14-, and 21-d-old suckling piglets and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age. The results showed that the percentage of proliferating cell nuclear antigen(PCNA)-positive cells and alkaline phosphatase(AKP) activity, as well as the abundances of E-cadherin,occludin, and Kv1.5 m RNA and claudin-1, claudin-3, and occludin protein in the jejunum were increased from d 1to d 21 during the suckling period(P 〈 0.05). Weaning induced decreases in the percentage of PCNA-positive cells,AKP activity and the abundances of E-cadherin, occludin and zonula occludens(ZO)-1 m RNA or protein in the jejunum on d 1, 3 and 5 post-weaning(P 〈 0.05). There were lower abundances of E-cadherin, occludin and ZO-1m RNA as well as claudin-1, claudin-3 and ZO-1 protein in the jejunum of weanling piglets than in 21-d-old suckling piglets(P 〈 0.05). The abundances of E-cadherin, occludin, ZO-1 and integrin m RNA were positively related to the percentage of PCNA-positive cells.Conclusion: Weaning at 14 d of age induced damage to the intestinal morphology and barrier. While there was an adaptive restoration on d 7 post-weaning, the measured values did not return to the pre-weaning levels, which reflected the impairment of intercellular junctions and Kv channels.展开更多
Objective: A variety of ion channels have been implicated in breast cancer proliferation and metastasis.Voltagegated K+(Kv) channels not only cause repolarization in excitable cells,but are also involved in multiple c...Objective: A variety of ion channels have been implicated in breast cancer proliferation and metastasis.Voltagegated K+(Kv) channels not only cause repolarization in excitable cells,but are also involved in multiple cellular functions in non-excitable cells.In this study we investigated the role of Kv channels in migration of BT474 breast cancer cells.Methods: Transwell technique was used to separate migratory cells from non-migratory ones and these two groups of cells were subject to electrophysiological examinations and microfluorimetric measurements for cytosolic Ca.Cell migration was examined in the absence or presence of Kv channel blockers.Results: When compared with non-migratory cells,migratory cells had much higher Kv current densities,but rather unexpectedly,more depolarized membrane potential and reduced Cainflux.Reverse transcriptasepolymerase chain reaction(RT-PCR) analysis revealed the presence of Kv1.1,Kv1.3,Kv1.5,Kv2.1,Kv3.3,Kv3.4 and Kv4.3 channels.Cell migration was markedly inhibited by tetraethylammonium(TEA),a delayed rectifier Kv channel blocker,but not by 4-aminopyridine,an A-type Kv channel blocker.Conclusions: Taken together,our results show that increased Kv channel expression played a role in BT474 cell migration,and Kv channels could be considered as biomarkers or potential therapeutic targets for breast cancer metastasis.The mechanism(s) by which Kv channels enhanced migration appeared unrelated to membrane hyperpolarization and Cainflux.展开更多
Background Ketanserin (KT), a selective serotonin (5-HT) 2-receptor antagonist, reduces peripheral blood pressure by blocking the activation of peripheral 5-HT receptors. In this study electrophysiological method ...Background Ketanserin (KT), a selective serotonin (5-HT) 2-receptor antagonist, reduces peripheral blood pressure by blocking the activation of peripheral 5-HT receptors. In this study electrophysiological method was used to investigate the effect of KT and potassium ion on Kv1.3 potassium channels and explore the role of blocker KT in the alteration of channel kinetics contributing to the potassium ion imbalances. Methods Kv1.3 channels were expressed in xenopus oocytes, and currents were measured using the two-microelectrode voltage-clamp technique. Results KCI made a left shift of activation and an inactivation curve of Kv1.3 current and accelerated the activation and inactivation time constant. High extracellular [K^+] attenuated the blockade effect of KT on Kv1.3 channels. In the presence of KT and KCI the activation and inactivation time constants were not influenced significantly no matter what was administered first. KT did not significantly inhibit Kv1.3 current induced by tetraethylammonium (TEA). Conclusions KT is a weak blocker of Kv1.3 channels at different concentrations of extracellular potassium and binds to the intracellular side of the channel pore. The inhibitor KT of ion channels is not fully effective in clinical use because of high [K^+]. and other electrolyte disorders.展开更多
This study aimed to comprehend the largely unknown role of voltage-gated potassium channel 1.3 (Kvl.3) in the phagocytic function of macrophages. We found that blocking of the Kv 1.3 channel with 100 pmol L 1 Sticho...This study aimed to comprehend the largely unknown role of voltage-gated potassium channel 1.3 (Kvl.3) in the phagocytic function of macrophages. We found that blocking of the Kv 1.3 channel with 100 pmol L 1 Stichodactyla helianthus neurotoxin (ShK) enhanced the phagocytic capacities of both resting and lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages in the chicken erythrocyte system. In the fluorescein isothiocyanate (FITC)-labeled Escherichia coli k-12 system, ShK increased the phagocytic capacities of resting RAW264.7 cells, but not of the LPS-stimulated cells, as LPS alone stimulated almost satu- rated phagocytosis of the macrophages. ShK increased the nitric oxide (NO) production in LPS-activated cells, but not in rest- ing RAW264.7 cells. There was no effect of ShK alone on the cytokine secretions in resting RAW264.7 cells, but it suppressed IL-113 secretion in LPS-stimulated RAW264.7 cells. At a concentration of 100 pmol L 1, ShK did not affect the viability of the tested cells. Kv 1.3 was expressed in RAW264.7 cells; this expression was downregulated by LPS, but significantly upregulat- ed by disrupting caveolin-dependent endocytosis with filipin III. In addition, cytochalasin D, an inhibitor of actin polymeriza- tion, did not affect the Kvl.3 expression. Thus, blocking of the Kvl.3 channel enhances the phagocytic capacity and NO pro- duction of this cell line. Our results suggest that Kv 1.3 channel serves as a negative regulator of phagocytosis in macrophages and can therefore be a potential target in the treatment of macrophage dysfunction.展开更多
The pathogenesis of the second major neurodegenerative disorder, Parkinson’s disease(PD), is closely associated with the dysfunction of potassium(K~+ ) channels. Therefore, PD is also considered to be an ion channel ...The pathogenesis of the second major neurodegenerative disorder, Parkinson’s disease(PD), is closely associated with the dysfunction of potassium(K~+ ) channels. Therefore, PD is also considered to be an ion channel disease or neuronal channelopathy. Mounting evidence has shown that K~+ channels play crucial roles in the regulations of neurotransmitter release, neuronal excitability, and cell volume. Inhibition of K~+ channels enhances the spontaneous firing frequency of nigral dopamine(DA)neurons, induces a transition from tonic firing to burst discharge, and promotes the release of DA in the striatum.Recently, three K~+ channels have been identified to protect DA neurons and to improve the motor and non-motor symptoms in PD animal models: small conductance(SK)channels, A-type K~+ channels, and KV7/KCNQ channels.In this review, we summarize the physiological and pharmacological effects of the three K~+ channels. We also describe in detail the laboratory investigations regarding K~+ channels as a potential therapeutic target for PD.展开更多
基金funded by the National Key Basic Research Program of China(2013CB127302)National Natural Science Foundation of China(31330075,31372326,31301988,31301989)+4 种基金the State Key Laboratory of Animal Nutrition(2004DA125184F1401)the Spark Program of Jiangxi Province(20142BBF061051)Changsha Lvye Biotechnology Limited Company Academician Expert WorkstationGuangdong Wangda Group Academician Workstation for Clean Feed Technology Research and Development in SwineGuangdong Hinapharm Group Academician Workstation for Biological Feed and Feed Additives and Animal Intestinal Health
文摘Background: The intestinal epithelium is an important barrier that depends on a complex mixture of proteins and these proteins comprise different intercellular junctions. The purpose of this study was to investigate the postnatal and developmental changes in morphology, intercellular junctions and voltage-gated potassium(Kv) channels in the intestine of piglets during the suckling and post-weaning periods.Results: Samples of the small intestine were obtained from 1-, 7-, 14-, and 21-d-old suckling piglets and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age. The results showed that the percentage of proliferating cell nuclear antigen(PCNA)-positive cells and alkaline phosphatase(AKP) activity, as well as the abundances of E-cadherin,occludin, and Kv1.5 m RNA and claudin-1, claudin-3, and occludin protein in the jejunum were increased from d 1to d 21 during the suckling period(P 〈 0.05). Weaning induced decreases in the percentage of PCNA-positive cells,AKP activity and the abundances of E-cadherin, occludin and zonula occludens(ZO)-1 m RNA or protein in the jejunum on d 1, 3 and 5 post-weaning(P 〈 0.05). There were lower abundances of E-cadherin, occludin and ZO-1m RNA as well as claudin-1, claudin-3 and ZO-1 protein in the jejunum of weanling piglets than in 21-d-old suckling piglets(P 〈 0.05). The abundances of E-cadherin, occludin, ZO-1 and integrin m RNA were positively related to the percentage of PCNA-positive cells.Conclusion: Weaning at 14 d of age induced damage to the intestinal morphology and barrier. While there was an adaptive restoration on d 7 post-weaning, the measured values did not return to the pre-weaning levels, which reflected the impairment of intercellular junctions and Kv channels.
基金funded by the Macao Science and Technology Development Fund(FUNDO PARA O DESENVOLVIMENTO DAS CIêNCIAS E DA TECNOLOGIA)and the reference number was 002/2015/A1
文摘Objective: A variety of ion channels have been implicated in breast cancer proliferation and metastasis.Voltagegated K+(Kv) channels not only cause repolarization in excitable cells,but are also involved in multiple cellular functions in non-excitable cells.In this study we investigated the role of Kv channels in migration of BT474 breast cancer cells.Methods: Transwell technique was used to separate migratory cells from non-migratory ones and these two groups of cells were subject to electrophysiological examinations and microfluorimetric measurements for cytosolic Ca.Cell migration was examined in the absence or presence of Kv channel blockers.Results: When compared with non-migratory cells,migratory cells had much higher Kv current densities,but rather unexpectedly,more depolarized membrane potential and reduced Cainflux.Reverse transcriptasepolymerase chain reaction(RT-PCR) analysis revealed the presence of Kv1.1,Kv1.3,Kv1.5,Kv2.1,Kv3.3,Kv3.4 and Kv4.3 channels.Cell migration was markedly inhibited by tetraethylammonium(TEA),a delayed rectifier Kv channel blocker,but not by 4-aminopyridine,an A-type Kv channel blocker.Conclusions: Taken together,our results show that increased Kv channel expression played a role in BT474 cell migration,and Kv channels could be considered as biomarkers or potential therapeutic targets for breast cancer metastasis.The mechanism(s) by which Kv channels enhanced migration appeared unrelated to membrane hyperpolarization and Cainflux.
文摘Background Ketanserin (KT), a selective serotonin (5-HT) 2-receptor antagonist, reduces peripheral blood pressure by blocking the activation of peripheral 5-HT receptors. In this study electrophysiological method was used to investigate the effect of KT and potassium ion on Kv1.3 potassium channels and explore the role of blocker KT in the alteration of channel kinetics contributing to the potassium ion imbalances. Methods Kv1.3 channels were expressed in xenopus oocytes, and currents were measured using the two-microelectrode voltage-clamp technique. Results KCI made a left shift of activation and an inactivation curve of Kv1.3 current and accelerated the activation and inactivation time constant. High extracellular [K^+] attenuated the blockade effect of KT on Kv1.3 channels. In the presence of KT and KCI the activation and inactivation time constants were not influenced significantly no matter what was administered first. KT did not significantly inhibit Kv1.3 current induced by tetraethylammonium (TEA). Conclusions KT is a weak blocker of Kv1.3 channels at different concentrations of extracellular potassium and binds to the intracellular side of the channel pore. The inhibitor KT of ion channels is not fully effective in clinical use because of high [K^+]. and other electrolyte disorders.
基金supported by the National Key Basic Research Program of China(2011CB93350)National Natural Science Foundation of China(31171088,31471126,81470540,81300139)
文摘This study aimed to comprehend the largely unknown role of voltage-gated potassium channel 1.3 (Kvl.3) in the phagocytic function of macrophages. We found that blocking of the Kv 1.3 channel with 100 pmol L 1 Stichodactyla helianthus neurotoxin (ShK) enhanced the phagocytic capacities of both resting and lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages in the chicken erythrocyte system. In the fluorescein isothiocyanate (FITC)-labeled Escherichia coli k-12 system, ShK increased the phagocytic capacities of resting RAW264.7 cells, but not of the LPS-stimulated cells, as LPS alone stimulated almost satu- rated phagocytosis of the macrophages. ShK increased the nitric oxide (NO) production in LPS-activated cells, but not in rest- ing RAW264.7 cells. There was no effect of ShK alone on the cytokine secretions in resting RAW264.7 cells, but it suppressed IL-113 secretion in LPS-stimulated RAW264.7 cells. At a concentration of 100 pmol L 1, ShK did not affect the viability of the tested cells. Kv 1.3 was expressed in RAW264.7 cells; this expression was downregulated by LPS, but significantly upregulat- ed by disrupting caveolin-dependent endocytosis with filipin III. In addition, cytochalasin D, an inhibitor of actin polymeriza- tion, did not affect the Kvl.3 expression. Thus, blocking of the Kvl.3 channel enhances the phagocytic capacity and NO pro- duction of this cell line. Our results suggest that Kv 1.3 channel serves as a negative regulator of phagocytosis in macrophages and can therefore be a potential target in the treatment of macrophage dysfunction.
基金supported by the National Natural Science Foundation of China(31671054 and 81430024)the Postdoctoral Science Foundation of China(2017M610412)the Bureau of Science and Technology of Qingdao Municipality,China(17-1-1-44-jch)
文摘The pathogenesis of the second major neurodegenerative disorder, Parkinson’s disease(PD), is closely associated with the dysfunction of potassium(K~+ ) channels. Therefore, PD is also considered to be an ion channel disease or neuronal channelopathy. Mounting evidence has shown that K~+ channels play crucial roles in the regulations of neurotransmitter release, neuronal excitability, and cell volume. Inhibition of K~+ channels enhances the spontaneous firing frequency of nigral dopamine(DA)neurons, induces a transition from tonic firing to burst discharge, and promotes the release of DA in the striatum.Recently, three K~+ channels have been identified to protect DA neurons and to improve the motor and non-motor symptoms in PD animal models: small conductance(SK)channels, A-type K~+ channels, and KV7/KCNQ channels.In this review, we summarize the physiological and pharmacological effects of the three K~+ channels. We also describe in detail the laboratory investigations regarding K~+ channels as a potential therapeutic target for PD.