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1.
Eur J Pharmacol ; 899: 174026, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33722592

RESUMO

Riluzole is an anticonvulsant drug also used to treat the amyotrophic lateral sclerosis and major depressive disorder. This compound has antiglutamatergic activity and is an important multichannel blocker. However, little is known about its actions on the Kv4.2 channels, the molecular correlate of the A-type K+ current (IA) and the fast transient outward current (Itof). Here, we investigated the effects of riluzole on Kv4.2 channels transiently expressed in HEK-293 cells. Riluzole inhibited Kv4.2 channels with an IC50 of 190 ± 14 µM and the effect was voltage- and frequency-independent. The activation rate of the current (at +50 mV) was not affected by the drug, nor the voltage dependence of channel activation, but the inactivation rate was accelerated by 100 and 300 µM riluzole. When Kv4.2 channels were maintained at the closed state, riluzole incubation induced a tonic current inhibition. In addition, riluzole significantly shifted the voltage dependence of inactivation to hyperpolarized potentials without affecting the recovery from inactivation. In the presence of the drug, the closed-state inactivation was significantly accelerated, and the percentage of inactivated channels was increased. Altogether, our findings indicate that riluzole inhibits Kv4.2 channels mainly affecting the closed and closed-inactivated states.


Assuntos
Bloqueadores dos Canais de Potássio/farmacologia , Riluzol/farmacologia , Canais de Potássio Shal/antagonistas & inibidores , Células HEK293 , Humanos , Ativação do Canal Iônico , Potenciais da Membrana , Canais de Potássio Shal/genética , Canais de Potássio Shal/metabolismo , Fatores de Tempo
2.
J Pharmacol Exp Ther ; 377(2): 265-272, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33674391

RESUMO

Drug-induced long QT syndrome (LQTS) is an established cardiac side effect of a wide range of medications and represents a significant concern for drug safety. The rapidly and slowly activating delayed rectifier K+ currents, mediated by channels encoded by the human ether-a-go-go-related gene (hERG) and KCNQ1 + KCNE1, respectively, are two main currents responsible for ventricular repolarization. The common cause for drugs to induce LQTS is through impairing the hERG channel. For the recent emergence of COVID-19, caused by severe acute respiratory syndrome coronavirus 2, several drugs have been investigated as potential therapies; however, there are concerns about their QT prolongation risk. Here, we studied the effects of chloroquine, hydroxychloroquine, azithromycin, and remdesivir on hERG channels. Our results showed that although chloroquine acutely blocked hERG current (IhERG), with an IC50 of 3.0 µM, hydroxychloroquine acutely blocked IhERG 8-fold less potently, with an IC50 of 23.4 µM. Azithromycin and remdesivir did not acutely affect IhERG When these drugs were added at 10 µM to the cell culture medium for 24 hours, remdesivir increased IhERG by 2-fold, which was associated with an increased mature hERG channel expression. In addition, these four drugs did not acutely or chronically affect KCNQ1 + KCNE1 channels. Our data provide insight into COVID-19 drug-associated LQTS and cardiac safety concerns. SIGNIFICANCE STATEMENT: This work demonstrates that, among off-label potential COVID-19 treatment drugs chloroquine, hydroxychloroquine, azithromycin, and remdesivir, the former two drugs block hERG potassium channels, whereas the latter two drugs do not. All four drugs do not affect KCNQ1 + KCNE1. As hERG and KCNQ1 + KCNE1 are two main K+ channels responsible for ventricular repolarization, and most drugs that induce long QT syndrome (LQTS) do so by impairing hERG channels, these data provide insight into COVID-19 drug-associated LQTS and cardiac safety concerns.


Assuntos
Monofosfato de Adenosina/análogos & derivados , Alanina/análogos & derivados , Azitromicina/farmacologia , Cloroquina/farmacologia , Canal de Potássio ERG1/antagonistas & inibidores , Hidroxicloroquina/farmacologia , Monofosfato de Adenosina/farmacologia , Monofosfato de Adenosina/uso terapêutico , Alanina/farmacologia , Alanina/uso terapêutico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Antivirais/farmacologia , Antivirais/uso terapêutico , Azitromicina/uso terapêutico , Cloroquina/uso terapêutico , Relação Dose-Resposta a Droga , Canal de Potássio ERG1/metabolismo , Células HEK293 , Humanos , Hidroxicloroquina/uso terapêutico , Bloqueadores dos Canais de Potássio/farmacologia , Bloqueadores dos Canais de Potássio/uso terapêutico
3.
Int J Mol Sci ; 22(4)2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33671466

RESUMO

During capacitation, sperm undergo a myriad of changes, including remodeling of plasma membrane, modification of sperm motility and kinematic parameters, membrane hyperpolarization, increase in intracellular calcium levels, and tyrosine phosphorylation of certain sperm proteins. While potassium channels have been reported to be crucial for capacitation of mouse and human sperm, their role in pigs has not been investigated. With this purpose, sperm samples from 15 boars were incubated in capacitation medium for 300 min with quinine, a general blocker of potassium channels (including voltage-gated potassium channels, calcium-activated potassium channels, and tandem pore domain potassium channels), and paxilline (PAX), a specific inhibitor of calcium-activated potassium channels. In all samples, acrosome exocytosis was induced after 240 min of incubation with progesterone. Plasma membrane and acrosome integrity, membrane lipid disorder, intracellular calcium levels, mitochondrial membrane potential, and total and progressive sperm motility were evaluated after 0, 120, and 240 min of incubation, and after 5, 30, and 60 min of progesterone addition. Although blocking potassium channels with quinine and PAX prevented sperm to elicit in vitro capacitation by impairing motility and mitochondrial function, as well as reducing intracellular calcium levels, the extent of that inhibition was larger with quinine than with PAX. Therefore, while our data support that calcium-activated potassium channels are essential for sperm capacitation in pigs, they also suggest that other potassium channels, such as the voltage-gated, tandem pore domain, and mitochondrial ATP-regulated ones, are involved in that process. Thus, further research is needed to elucidate the specific functions of these channels and the mechanisms underlying its regulation during sperm capacitation.


Assuntos
Acrossomo/metabolismo , Exocitose/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/metabolismo , Progesterona/farmacologia , Capacitação Espermática/efeitos dos fármacos , Acrossomo/efeitos dos fármacos , Animais , Cálcio/metabolismo , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Paxilina/farmacologia , Quinina/farmacologia , Motilidade Espermática/efeitos dos fármacos , Suínos
4.
Am J Physiol Heart Circ Physiol ; 320(4): H1456-H1469, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33635168

RESUMO

Ventricular arrhythmia (VA) is the major cause of death in patients with left ventricular (LV) hypertrophy and/or acute ischemia. We hypothesized that apamin, a blocker of small-conductance Ca2+-activated K+ (SK) channels, alters Ca2+ handling and exhibits anti-arrhythmic effects in ventricular myocardium. Spontaneous hypertensive rats were used as a model of LV hypertrophy. A dual optical mapping of membrane potential (Vm) and intracellular calcium (Cai) was performed during global hypoxia (GH) on the Langendorff perfusion system. The majority of pacing-induced VAs during GH were initiated by triggered activities. Pretreatment of apamin (100 nmol/L) significantly inhibited the VA inducibility. Compared with SK channel blockers (apamin and NS8593), non-SK channel blockers (glibenclamide and 4-AP) did not exhibit anti-arrhythmic effects. Apamin prevented not only action potential duration (APD80) shortening (-18.7 [95% confidence interval, -35.2 to -6.05] ms vs. -2.75 [95% CI, -10.45 to 12.65] ms, P = 0.04) but also calcium transient duration (CaTD80) prolongation (14.52 [95% CI, 8.8-20.35] ms vs. 3.85 [95% CI, -3.3 to 12.1] ms, P < 0.01), thereby reducing CaTD80 - APD80, which denotes "Cai/Vm uncoupling" (33.22 [95% CI, 22-48.4] ms vs. 6.6 [95% CI, 0-14.85] ms, P < 0.01). The reduction of Cai/Vm uncoupling was attributable to less prolonged Ca2+ decay constant and suppression of diastolic Cai increase by apamin. The inhibition of VA inducibility and changes in APs/CaTs parameters caused by apamin was negated by the addition of ouabain, an inhibitor of Na+/K+ pump. Apamin attenuates APD shortening, Ca2+ handling abnormalities, and Cai/Vm uncoupling, leading to inhibition of VA occurrence in hypoxic hypertrophied hearts.NEW & NOTEWORTHY We demonstrated that hypoxia-induced ventricular arrhythmias were mainly initiated by Ca2+-loaded triggered activities in hypertrophied hearts. The blockades of small-conductance Ca2+-activated K+ channels, especially "apamin," showed anti-arrhythmic effects by alleviation of not only action potential duration shortening but also Ca2+ handling abnormalities, most notably the "Ca2+/voltage uncoupling."


Assuntos
Antiarrítmicos/farmacologia , Arritmias Cardíacas/prevenção & controle , Sinalização do Cálcio/efeitos dos fármacos , Cardiomegalia/tratamento farmacológico , Frequência Cardíaca/efeitos dos fármacos , Hipóxia/tratamento farmacológico , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Ativados por Cálcio de Condutância Baixa/antagonistas & inibidores , 1-Naftilamina/análogos & derivados , 1-Naftilamina/farmacologia , Potenciais de Ação/efeitos dos fármacos , Animais , Apamina/farmacologia , Arritmias Cardíacas/etiologia , Arritmias Cardíacas/metabolismo , Arritmias Cardíacas/fisiopatologia , Estimulação Cardíaca Artificial , Cardiomegalia/complicações , Cardiomegalia/metabolismo , Cardiomegalia/fisiopatologia , Modelos Animais de Doenças , Hipóxia/complicações , Hipóxia/metabolismo , Hipóxia/fisiopatologia , Preparação de Coração Isolado , Masculino , Ratos Endogâmicos SHR , Canais de Potássio Ativados por Cálcio de Condutância Baixa/metabolismo , Fatores de Tempo
5.
Am J Physiol Cell Physiol ; 320(4): C520-C546, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33326312

RESUMO

Several potassium channels (KCs) have been described throughout the gastrointestinal tract. Notwithstanding, their contribution to both physiologic and pathophysiologic conditions, as inflammatory bowel disease (IBD), remains underexplored. Therefore, we aim to systematically review, for the first time, the evidence on the characteristics and modulation of KCs in intestinal epithelial cells (IECs). PubMed, Scopus, and Web of Science were searched to identify studies focusing on KCs and their modulation in IECs. The included studies were assessed using a reporting inclusiveness checklist. From the 745 identified records, 73 met the inclusion criteria; their reporting inclusiveness was moderate-high. Some studies described the physiological role of KCs, while others explored their importance in pathological settings. Globally, in IBD animal models, apical KCa1.1 channels, responsible for luminal secretion, were upregulated. In human colonocytes, basolateral KCa3.1 channels were downregulated. The pharmacological inhibition of K2P and Kv influenced intestinal barrier function, promoting inflammation. Evidence suggests a strong association between KCs expression and secretory mechanisms in human and animal IECs. Further research is warranted to explore the usefulness of KC pharmacological modulation as a therapeutic target.


Assuntos
Células Epiteliais/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/efeitos dos fármacos , Animais , Linhagem Celular , Células Epiteliais/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Potenciais da Membrana , Canais de Potássio/metabolismo , Transdução de Sinais
6.
PLoS Comput Biol ; 16(12): e1008463, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33315892

RESUMO

Cerebellar stellate cells (CSCs) are spontaneously active, tonically firing (5-30 Hz), inhibitory interneurons that synapse onto Purkinje cells. We previously analyzed the excitability properties of CSCs, focusing on four key features: type I excitability, non-monotonic first-spike latency, switching in responsiveness and runup (i.e., temporal increase in excitability during whole-cell configuration). In this study, we extend this analysis by using whole-cell configuration to show that these neurons can also burst when treated with certain pharmacological agents separately or jointly. Indeed, treatment with 4-Aminopyridine (4-AP), a partial blocker of delayed rectifier and A-type K+ channels, at low doses induces a bursting profile in CSCs significantly different than that produced at high doses or when it is applied at low doses but with cadmium (Cd2+), a blocker of high voltage-activated (HVA) Ca2+ channels. By expanding a previously revised Hodgkin-Huxley type model, through the inclusion of Ca2+-activated K+ (K(Ca)) and HVA currents, we explain how these bursts are generated and what their underlying dynamics are. Specifically, we demonstrate that the expanded model preserves the four excitability features of CSCs, as well as captures their bursting patterns induced by 4-AP and Cd2+. Model investigation reveals that 4-AP is potentiating HVA, inducing square-wave bursting at low doses and pseudo-plateau bursting at high doses, whereas Cd2+ is potentiating K(Ca), inducing pseudo-plateau bursting when applied in combination with low doses of 4-AP. Using bifurcation analysis, we show that spike adding in square-wave bursts is non-sequential when gradually changing HVA and K(Ca) maximum conductances, delayed Hopf is responsible for generating the plateau segment within the active phase of pseudo-plateau bursts, and bursting can become "chaotic" when HVA and K(Ca) maximum conductances are made low and high, respectively. These results highlight the secondary effects of the drugs applied and suggest that CSCs have all the ingredients needed for bursting.


Assuntos
4-Aminopiridina/farmacologia , Potenciais de Ação/efeitos dos fármacos , Cádmio/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Cerebelo/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Células de Purkinje/efeitos dos fármacos , 4-Aminopiridina/administração & dosagem , Animais , Cádmio/administração & dosagem , Cerebelo/citologia , Cerebelo/fisiologia , Relação Dose-Resposta a Droga , Camundongos , Camundongos Endogâmicos C57BL , Modelos Biológicos , Técnicas de Patch-Clamp , Células de Purkinje/fisiologia
7.
Int J Mol Sci ; 21(24)2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-33316951

RESUMO

Pentagalloyglucose (PGG, penta-O-galloyl-ß-d-glucose; 1,2,3,4,6-pentagalloyl glucose), a pentagallic acid ester of glucose, is recognized to possess anti-bacterial, anti-oxidative and anti-neoplastic activities. However, to what extent PGG or other polyphenolic compounds can perturb the magnitude and/or gating of different types of plasmalemmal ionic currents remains largely uncertain. In pituitary tumor (GH3) cells, we found out that PGG was effective at suppressing the density of delayed-rectifier K+ current (IK(DR)) concentration-dependently. The addition of PGG could suppress the density of proton-activated Cl- current (IPAC) observed in GH3 cells. The IC50 value required for the inhibitory action of PGG on IK(DR) or IPAC observed in GH3 cells was estimated to be 3.6 or 12.2 µM, respectively, while PGG (10 µM) mildly inhibited the density of the erg-mediated K+ current or voltage-gated Na+ current. The presence of neither chlorotoxin, hesperetin, kaempferol, morin nor iberiotoxin had any effects on IPAC density, whereas hydroxychloroquine or 4-[(2-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inden-5yl)oxy] butanoic acid suppressed current density effectively. The application of PGG also led to a decrease in the area of voltage-dependent hysteresis of IPAC elicited by long-lasting isosceles-triangular ramp voltage command, suggesting that hysteretic strength was lessened in its presence. In human cardiac myocytes, the exposure to PGG also resulted in a reduction of ramp-induced IK(DR) density. Taken literally, PGG-perturbed adjustment of ionic currents could be direct and appears to be independent of its anti-oxidative property.


Assuntos
Potenciais de Ação , Taninos Hidrolisáveis/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Bloqueadores dos Canais de Sódio/farmacologia , Linhagem Celular , Humanos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/fisiologia , Canais de Potássio/metabolismo , Canais de Sódio/metabolismo
8.
Arterioscler Thromb Vasc Biol ; 40(10): 2360-2375, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32787516

RESUMO

OBJECTIVE: Platelet activation by stimulatory factors leads to an increase in intracellular calcium concentration ([Ca2+]i), which is essential for almost all platelet functions. Modulation of Ca2+ influx and [Ca2+]i in platelets has been emerging as a possible strategy for preventing and treating platelet-dependent thrombosis. Voltage-gated potassium 1.3 channels (Kv1.3) are highly expressed in platelets and able to regulate agonist-evoked [Ca2+]i increase. However, the role of Kv1.3 channels in regulating platelet functions and thrombosis has not yet been elucidated. In addition, it is difficult to obtain a specific blocker for this channel, since Kv1.3 shares identical drug-binding sites with other K+ channels. Here, we investigate whether specific blockade of Kv1.3 channels by monoclonal antibodies affects platelet functions and thrombosis. Approach and Results: In this study, we produced the anti-Kv1.3 monoclonal antibody 6E12#15, which could specifically recognize both human and mouse Kv1.3 proteins and sufficiently block Kv1.3 channel currents. We found Kv1.3 blockade by 6E12#15 inhibited platelet aggregation, adhesion, and activation upon agonist stimulation. In vivo treatment with 6E12#15 alleviated thrombus formation in a mesenteric arteriole thrombosis mouse model and protected mice from collagen/epinephrine-induced pulmonary thromboembolism. Furthermore, we observed Kv1.3 regulated platelet functions by modulating Ca2+ influx and [Ca2+]i elevation, and that this is mediated in part by P2X1. Interestingly, Kv1.3-/- mice showed impaired platelet aggregation while displayed no abnormalities in in vivo thrombus formation. This phenomenon was related to more megakaryocytes and platelets produced in Kv1.3-/- mice compared with wild-type mice. CONCLUSIONS: We showed specific inhibition of Kv1.3 by the novel monoclonal antibody 6E12#15 suppressed platelet functions and platelet-dependent thrombosis through modulating platelet [Ca2+]i elevation. These results indicate that Kv1.3 could act as a promising therapeutic target for antiplatelet therapies.


Assuntos
Anticorpos Monoclonais/farmacologia , Plaquetas/efeitos dos fármacos , Fibrinolíticos/farmacologia , Canal de Potássio Kv1.3/antagonistas & inibidores , Inibidores da Agregação Plaquetária/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Embolia Pulmonar/prevenção & controle , Trombose/prevenção & controle , Animais , Coagulação Sanguínea/efeitos dos fármacos , Plaquetas/metabolismo , Modelos Animais de Doenças , Feminino , Células HEK293 , Humanos , Canal de Potássio Kv1.3/sangue , Canal de Potássio Kv1.3/deficiência , Canal de Potássio Kv1.3/genética , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ativação Plaquetária/efeitos dos fármacos , Embolia Pulmonar/sangue , Embolia Pulmonar/genética , Embolia Pulmonar/metabolismo , Transdução de Sinais , Trombose/sangue , Trombose/genética , Trombose/metabolismo
9.
Toxicol Lett ; 332: 88-96, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32629073

RESUMO

The human ether-a-go-go-related gene (hERG) encodes a tetrameric potassium channel called Kv11.1. This channel can be blocked by certain drugs, which leads to long QT syndrome, causing cardiotoxicity. This is a significant problem during drug development. Using computer models to predict compound cardiotoxicity during the early stages of drug design will help to solve this problem. In this study, we used a dataset of 1865 compounds exhibiting known hERG inhibitory activities as a training set. Thirty cardiotoxicity classification models were established using three machine learning algorithms based on molecular fingerprints and molecular descriptors. Through using these models as the base classifier, a new cardiotoxicity classification model with better predictive performance was developed using ensemble learning method. The accuracy of the best base classifier, which was generated using the XGBoost method with molecular descriptors, was 84.8 %, and the area under the receiver-operating characteristic curve (AUC) was 0.876 in the five fold cross-validation. However, all of the ensemble models that we developed had higher predictive performance than the base classifiers in the five fold cross-validation. The best predictive performance was achieved by the Ensemble-Top7 model, with accuracy of 84.9 % and AUC of 0.887. We also tested the ensemble model using external validation data and achieved accuracy of 85.0 % and AUC of 0.786. Furthermore, we identified several hERG-related substructures, which provide valuable information for designing drug candidates.


Assuntos
Canal de Potássio ERG1/antagonistas & inibidores , Aprendizado de Máquina , Mapeamento de Peptídeos/métodos , Bloqueadores dos Canais de Potássio/farmacologia , Algoritmos , Animais , Área Sob a Curva , Células CHO , Cardiotoxicidade , Cricetinae , Cricetulus , Bases de Dados Factuais , Humanos , Modelos Moleculares , Valor Preditivo dos Testes , Máquina de Vetores de Suporte
10.
Life Sci ; 257: 118070, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32668327

RESUMO

AIMS: Several studies suggested that ATP-sensitive potassium channels (KATP) are potential therapeutic targets for protection against various neurodegenerative disorders, yet, there is an ongoing controversy regarding their role in Parkinson's disease (PD). Thus, the aim of the current study is to investigate the protective effect of KATP blockade and activation in the mice rotenone model of PD. MAIN METHODS: PD has been induced by 9 subcutaneous injections of rotenone (1.5 mg/kg; 3 times/week) in adult male Swiss albino mice. For 3 consecutive weeks, parkinsonian mice were either untreated or treated with L-dopa (25 mg/kg), the KATP channel blocker glibenclamide (3 mg/kg) or the KATP channel opener nicorandil (6 mg/kg). KEY FINDINGS: Glibenclamide significantly improved motor performance in the wire hanging and stair tests and halted the decline in striatal dopamine content as well as dopaminergic neurons' density. In addition, it reduced the rotenone-induced apoptosis as portrayed in the immunohistopathological examination via increasing Bcl-2 and decreasing caspases-3, -8, -9 contents. Furthermore, through its anti-inflammatory potential, glibenclamide reduced tumor necrosis factor-alpha level. On the other hand, nicorandil failed to mitigate the rotenone-induced neurodegenerative consequences. SIGNIFICANCE: KATP channel blockade by glibenclamide has neuroprotective effect against rotenone-induced neurotoxicity, that was mediated by its anti-inflammatory effect along with hindering apoptosis through extrinsic and intrinsic pathways.


Assuntos
Glibureto/farmacologia , Canais KATP/antagonistas & inibidores , Fármacos Neuroprotetores/farmacologia , Transtornos Parkinsonianos/tratamento farmacológico , Bloqueadores dos Canais de Potássio/farmacologia , Animais , Apoptose/efeitos dos fármacos , Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Canais KATP/metabolismo , Levodopa/farmacologia , Masculino , Camundongos , Nicorandil/farmacologia , Transtornos Parkinsonianos/fisiopatologia , Rotenona/toxicidade
11.
Transl Res ; 224: 40-54, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32522668

RESUMO

The modulation of voltage-gated K+ (Kv) channels, involved in cell proliferation, arises as a potential therapeutic approach for the prevention of intimal hyperplasia present in in-stent restenosis (ISR) and allograft vasculopathy (AV). We studied the effect of PAP-1, a selective blocker of Kv1.3 channels, on development of intimal hyperplasia in vitro and in vivo in 2 porcine models of vascular injury. In vitro phenotypic modulation of VSMCs was associated to an increased functional expression of Kv1.3 channels, and only selective Kv1.3 channel blockers were able to inhibit porcine VSMC proliferation. The therapeutic potential of PAP-1 was then evaluated in vivo in swine models of ISR and AV. At 15-days follow-up, morphometric analysis demonstrated a substantial reduction of luminal stenosis in the allografts treated with PAP-1 (autograft 2.72 ± 1.79 vs allograft 10.32 ± 1.92 vs allograft + polymer 13.54 ± 8.59 vs allograft + polymer + PAP-1 3.06 ± 1.08 % of luminal stenosis; P = 0.006) in the swine model of femoral artery transplant. In the pig model of coronary ISR, using a prototype of PAP-1-eluting stent, no differences were observed regarding % of stenosis compared to control stents (31 ± 13 % vs 37 ± 18%, respectively; P = 0.372) at 28-days follow-up. PAP-1 treatment was safe and did not impair vascular healing in terms of delayed endothelialization, inflammation or thrombosis. However, an incomplete release of PAP-1 from stents was documented. We conclude that the use of selective Kv1.3 blockers represents a promising therapeutic approach for the prevention of intimal hyperplasia in AV, although further studies to improve their delivery method are needed to elucidate its potential in ISR.


Assuntos
Canal de Potássio Kv1.3/antagonistas & inibidores , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/patologia , Bloqueadores dos Canais de Potássio/farmacologia , Túnica Íntima/patologia , Aloenxertos/efeitos dos fármacos , Animais , Proliferação de Células/efeitos dos fármacos , Reestenose Coronária/patologia , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/lesões , Vasos Coronários/patologia , Modelos Animais de Doenças , Feminino , Artéria Femoral/efeitos dos fármacos , Artéria Femoral/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Hiperplasia , Canal de Potássio Kv1.3/genética , Canal de Potássio Kv1.3/metabolismo , Canal de Potássio Kv1.5/genética , Canal de Potássio Kv1.5/metabolismo , Modelos Biológicos , Miócitos de Músculo Liso/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Stents , Suínos , Túnica Íntima/efeitos dos fármacos
12.
Microvasc Res ; 131: 104030, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32531353

RESUMO

Previous studies indicate that sex-related differences exist in the regulation of cutaneous vasodilation, however, the mechanisms remain unresolved. We assessed if sex-differences in young adults exist for cholinergic, nicotinic, and ß-adrenergic cutaneous vasodilation with a focus on nitric oxide synthase (NOS), cyclooxygenase (COX), and K+ channel mechanisms. In twelve young men and thirteen young women, four intradermal forearm skin sites were perfused with the following: 1) lactated Ringer's solution (control), 2) 10 mM Nω-nitro-l-arginine, a non-selective NOS inhibitor, 3) 10 mM ketorolac, a non-selective COX inhibitor, or 4) 50 mM BaCl2, a nonspecific K+ channel blocker. At all four sites, cutaneous vasodilation was induced by 1) 10 mM nicotine, a nicotinic receptor agonist, 2) 100 µM isoproterenol, a nonselective ß-adrenergic receptor agonist, and 3) 2 mM and 2000 mM acetylcholine, an acetylcholine receptor agonist. Nicotine and isoproterenol were administered for 3 min, whereas each acetylcholine dose was administered for 25 min. Regardless of treatment site, cutaneous vasodilation in response to nicotine and a high dose of acetylcholine (2000 mM) were lower in women than men. By contrast, isoproterenol induced cutaneous vasodilation was greater in women vs. men. Irrespective of sex, NOS inhibition or K+ channel blockade attenuated isoproterenol-mediated cutaneous vasodilation, whereas K+ channel blockade decreased nicotine-induced cutaneous vasodilation. Taken together, our findings indicate that while the mechanisms underlying cutaneous vasodilation are comparable between young men and women, sex-related differences in the magnitude of cutaneous vasodilation do exist and this response differs as a function of the receptor agonist.


Assuntos
Vasos Sanguíneos/enzimologia , Óxido Nítrico Sintase/metabolismo , Canais de Potássio/metabolismo , Prostaglandina-Endoperóxido Sintases/metabolismo , Receptores Adrenérgicos beta/metabolismo , Receptores Colinérgicos/metabolismo , Pele/irrigação sanguínea , Vasodilatação , Agonistas Adrenérgicos beta/farmacologia , Adulto , Vasos Sanguíneos/efeitos dos fármacos , Agonistas Colinérgicos/farmacologia , Inibidores de Ciclo-Oxigenase/farmacologia , Feminino , Antebraço , Humanos , Masculino , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/efeitos dos fármacos , Receptores Nicotínicos/metabolismo , Fatores Sexuais , Transdução de Sinais , Vasodilatação/efeitos dos fármacos , Adulto Jovem
13.
Neuron ; 107(1): 52-64.e7, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32362337

RESUMO

At neuronal synapses, synaptotagmin-1 (syt1) acts as a Ca2+ sensor that synchronizes neurotransmitter release with Ca2+ influx during action potential firing. Heterozygous missense mutations in syt1 have recently been associated with a severe but heterogeneous developmental syndrome, termed syt1-associated neurodevelopmental disorder. Well-defined pathogenic mechanisms, and the basis for phenotypic heterogeneity in this disorder, remain unknown. Here, we report the clinical, physiological, and biophysical characterization of three syt1 mutations from human patients. Synaptic transmission was impaired in neurons expressing mutant variants, which demonstrated potent, graded dominant-negative effects. Biophysical interrogation of the mutant variants revealed novel mechanistic features concerning the cooperative action, and functional specialization, of the tandem Ca2+-sensing domains of syt1. These mechanistic studies led to the discovery that a clinically approved K+ channel antagonist is able to rescue the dominant-negative heterozygous phenotype. Our results establish a molecular cause, basis for phenotypic heterogeneity, and potential treatment approach for syt1-associated neurodevelopmental disorder.


Assuntos
Transtornos do Neurodesenvolvimento/genética , Neurônios/fisiologia , Transmissão Sináptica/genética , Sinaptotagmina I/genética , 4-Aminopiridina/farmacologia , Animais , Células Cultivadas , Humanos , Camundongos , Transtornos do Neurodesenvolvimento/fisiopatologia , Neurônios/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Transmissão Sináptica/efeitos dos fármacos , Sinaptotagmina I/química
14.
Am J Physiol Regul Integr Comp Physiol ; 319(1): R19-R25, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32401629

RESUMO

Microvascular endothelial dysfunction, a precursor to atherosclerotic cardiovascular disease, increases with aging. Endothelium-derived hyperpolarizing factors (EDHFs), which act through K+ channels, regulate blood flow and are important to vascular health. It is unclear how EDHFs change with healthy aging. To evaluate microvascular endothelial reliance on K+ channel-mediated dilation as a function of age in healthy humans. Microvascular function was assessed using intradermal microdialysis in healthy younger (Y; n = 7; 3 M/4 W; 26 ± 1 yr) and older adults (O; n = 12; 5 M/7 W; 64 ± 2 yr) matched for V̇o2peak (Y: 39.0 ± 3.8, O: 37.6 ± 3.1 mL·kg-1·min-1). Participants underwent graded local infusions of: the K+ channel activator Na2S (10-6 to 10-1 M), acetylcholine (ACh, 10-10 to 10-1 M), ACh + the K+ channel inhibitor tetraethylammonium (TEA; 25 or 50 mM), and ACh + the nitric oxide synthase-inhibitor l-NAME (15 mM). Red blood cell flux was measured with laser-Doppler flowmetry and used to calculate cutaneous vascular conductance (CVC; flux/mean arterial pressure) as a percentage of each site-specific maximum (%CVCmax, 43°C+28 mM sodium nitroprusside). The %CVCmax response to Na2S was higher in older adults (mean, O: 51.7 ± 3.9% vs. Y: 36.1 ± 5.3%; P = 0.03). %CVCmax was lower in the ACh+TEA vs. the ACh site starting at 10-5 M (ACh: 34.0 ± 5.7% vs. ACh+TEA: 19.4 ± 4.5%; P = 0.002) in older and at 10-4 M (ACh: 54.5 ± 9.4% vs. ACh+TEA: 31.2 ± 6.7%; P = 0.0002) in younger adults. %CVCmax was lower in the ACh+l-NAME vs. the ACh site in both groups starting at 10-4 M ACh (Y: P < 0.001; O: P = 0.02). Healthy active older adults have enhanced K+ channel-dependent endothelial vasodilatory mechanisms, suggesting increased responsiveness to EDHFs with age.


Assuntos
Endotélio Vascular/fisiologia , Envelhecimento Saudável/fisiologia , Canais de Potássio/fisiologia , Vasodilatação/fisiologia , Adulto , Idoso , Envelhecimento/fisiologia , Limiar Anaeróbio/fisiologia , Fatores Biológicos/fisiologia , Inibidores Enzimáticos/farmacologia , Eritrócitos/efeitos dos fármacos , Eritrócitos/fisiologia , Feminino , Humanos , Masculino , Microcirculação , Pessoa de Meia-Idade , NG-Nitroarginina Metil Éster/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/agonistas , Fluxo Sanguíneo Regional/fisiologia
15.
Am J Physiol Renal Physiol ; 318(6): F1369-F1376, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32308018

RESUMO

Cytochrome P-450 (Cyp) epoxygenase-dependent metabolites of arachidonic acid (AA) have been shown to inhibit renal Na+ transport, and inhibition of Cyp-epoxygenase is associated with salt-sensitive hypertension. We used the patch-clamp technique to examine whether Cyp-epoxygenase-dependent AA metabolites inhibited the basolateral 40-pS K+ channel (Kir4.1/Kir5.1) in the distal convoluted tubule (DCT). Application of AA inhibited the basolateral 40-pS K+ channel in the DCT. The inhibitory effect of AA on the 40-pS K+ channel was specific because neither linoleic nor oleic acid was able to mimic the effect of AA on the K+ channel. Inhibition of Cyp-monooxygenase with N-methylsulfonyl-12,12-dibromododec-11-enamide or inhibition of cyclooxygenase with indomethacin failed to abolish the inhibitory effect of AA on the 40-pS K+ channel. However, the inhibition of Cyp-epoxygenase with N-methylsulfonyl-6-(propargyloxyphenyl)hexanamide abolished the effect of AA on the 40-pS K+ channel in the DCT. Moreover, addition of either 11,12-epoxyeicosatrienoic acid (EET) or 14,15-EET also inhibited the 40-pS K+ channel in the DCT. Whole cell recording demonstrated that application of AA decreased, whereas N-methylsulfonyl-6-(propargyloxyphenyl)hexanamide treatment increased, Ba2+-sensitive K+ currents in the DCT. Finally, application of 14,15-EET but not AA was able to inhibit the basolateral 40-pS K+ channel in the DCT of Cyp2c44-/- mice. We conclude that Cyp-epoxygenase-dependent AA metabolites inhibit the basolateral Kir4.1/Kir5.1 in the DCT and that Cyp2c44-epoxygenase plays a role in the regulation of the basolateral K+ channel in the mouse DCT.


Assuntos
Ácido 8,11,14-Eicosatrienoico/análogos & derivados , Ácido Araquidônico/farmacologia , Família 2 do Citocromo P450/metabolismo , Túbulos Renais Distais/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Corretores do Fluxo de Internalização/antagonistas & inibidores , Ácido 8,11,14-Eicosatrienoico/metabolismo , Ácido 8,11,14-Eicosatrienoico/farmacologia , Amidas/farmacologia , Animais , Ácido Araquidônico/metabolismo , Família 2 do Citocromo P450/antagonistas & inibidores , Família 2 do Citocromo P450/genética , Inibidores Enzimáticos/farmacologia , Túbulos Renais Distais/metabolismo , Masculino , Potenciais da Membrana , Camundongos da Linhagem 129 , Camundongos Knockout , Bloqueadores dos Canais de Potássio/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo
16.
BMC Mol Cell Biol ; 21(1): 31, 2020 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-32306897

RESUMO

BACKGROUND: Cytoprotection afforded by mitochondrial ATP-sensitive K+-channel (mKATP-channel) opener diazoxide (DZ) largely depends on the activation of potassium cycle with eventual modulation of mitochondrial functions and ROS production. However, generally these effects were studied in the presence of Mg∙ATP known to block K+ transport. Thus, the purpose of our work was the estimation of DZ effects on K+ transport, K+ cycle and ROS production in rat liver mitochondria in the absence of Mg∙ATP. RESULTS: Without Mg·ATP, full activation of native mKATP-channel, accompanied by the increase in ATP-insensitive K+ uptake, activation of K+-cycle and respiratory uncoupling, was reached at ≤0.5 µM of DZ,. Higher diazoxide concentrations augmented ATP-insensitive K+ uptake, but not mKATP-channel activity. mKATP-channel was blocked by Mg·ATP, reactivated by DZ, and repeatedly blocked by mKATP-channel blockers glibenclamide and 5-hydroxydecanoate, whereas ATP-insensitive potassium transport was blocked by Mg2+ and was not restored by DZ. High sensitivity of potassium transport to DZ in native mitochondria resulted in suppression of mitochondrial ROS production caused by the activation of K+-cycle on sub-micromolar scale. Based on the oxygen consumption study, the share of mKATP-channel in respiratory uncoupling by DZ was found. CONCLUSIONS: The study of mKATP-channel activation by diazoxide in the absence of MgATP discloses novel, not described earlier, aspects of mKATP-channel interaction with this drug. High sensitivity of mKATP-channel to DZ results in the modulation of mitochondrial functions and ROS production by DZ on sub-micromolar concentration scale. Our experiments led us to the hypothesis that under the conditions marked by ATP deficiency affinity of mKATP-channel to DZ can increase, which might contribute to the high effectiveness of this drug in cardio- and neuroprotection.


Assuntos
Trifosfato de Adenosina/metabolismo , Diazóxido/farmacologia , Mitocôndrias Hepáticas/efeitos dos fármacos , Canais de Potássio/metabolismo , Potássio/metabolismo , Animais , Ácidos Decanoicos/farmacologia , Metabolismo Energético/efeitos dos fármacos , Feminino , Glibureto/farmacologia , Hidroxiácidos/farmacologia , Transporte de Íons/efeitos dos fármacos , Transporte de Íons/genética , Canais KATP/metabolismo , Magnésio/metabolismo , Mitocôndrias Hepáticas/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/metabolismo , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/genética , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo
17.
Ecotoxicol Environ Saf ; 196: 110519, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32244116

RESUMO

On two rat cell lines, pheochromocytoma PC12 and ascites hepatoma AS-30D, and on rat liver mitochondria we studied action of paxilline (lipophilic mycotoxin from fungus Penicillium paxilli which is blocker of large-conductance potassium channels) against harmful effects of Cd(II) - one of the most dangerous toxic metals and environmental pollutants. We investigated an influence of paxilline on cell viability and mitochondrial function in the presence and in the absence of Cd2+. As found, paxilline protected partially from the Cd2+-induced cytotoxicity, namely taken in concentration of 1 µM it decreased the Cd2+-induced cell necrosis in average by 10-14 or 13-23% for AS-30D and PC12 cells, respectively. Nevertheless, paxilline did not affect the Cd2+-induced apoptosis of AS-30D cells. The alleviating concentration of paxilline reduced an intracellular production of reactive oxygen species (ROS) in PC12 cells intoxicated by Cd2+ and enhanced the ROS production in control AS-30D cells; however, it weakly affected mitochondrial membrane potential of the cells in the absence and in the presence of Cd2+. The ameliorative concentration of paxilline decreased the maximal respiration rates of control cells of both types after short-term (3-5 h) treatment with it while the rates reached their control levels after long-term (24-48 h) incubation with the drug. Paxilline was not protective against the Cd2+-induced membrane permeability and respiration rate changes in isolated rat liver mitochondria. As result, the mitochondrial electron transport chain was concluded to contribute in the mitigating effect of paxilline against the Cd2+-produced cell injury.


Assuntos
Apoptose/efeitos dos fármacos , Cádmio/toxicidade , Poluentes Ambientais/toxicidade , Indóis/farmacologia , Mitocôndrias Hepáticas/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Animais , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , Necrose , Células PC12 , Ratos , Espécies Reativas de Oxigênio/metabolismo
18.
Brain ; 143(4): 1127-1142, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32293668

RESUMO

Chronic disability in multiple sclerosis is linked to neuroaxonal degeneration. 4-aminopyridine (4-AP) is used and licensed as a symptomatic treatment to ameliorate ambulatory disability in multiple sclerosis. The presumed mode of action is via blockade of axonal voltage gated potassium channels, thereby enhancing conduction in demyelinated axons. In this study, we provide evidence that in addition to those symptomatic effects, 4-AP can prevent neuroaxonal loss in the CNS. Using in vivo optical coherence tomography imaging, visual function testing and histologic assessment, we observed a reduction in retinal neurodegeneration with 4-AP in models of experimental optic neuritis and optic nerve crush. These effects were not related to an anti-inflammatory mode of action or a direct impact on retinal ganglion cells. Rather, histology and in vitro experiments indicated 4-AP stabilization of myelin and oligodendrocyte precursor cells associated with increased nuclear translocation of the nuclear factor of activated T cells. In experimental optic neuritis, 4-AP potentiated the effects of immunomodulatory treatment with fingolimod. As extended release 4-AP is already licensed for symptomatic multiple sclerosis treatment, we performed a retrospective, multicentre optical coherence tomography study to longitudinally compare retinal neurodegeneration between 52 patients on continuous 4-AP therapy and 51 matched controls. In line with the experimental data, during concurrent 4-AP therapy, degeneration of the macular retinal nerve fibre layer was reduced over 2 years. These results indicate disease-modifying effects of 4-AP beyond symptomatic therapy and provide support for the design of a prospective clinical study using visual function and retinal structure as outcome parameters.


Assuntos
4-Aminopiridina/farmacologia , Esclerose Múltipla/patologia , Fármacos Neuroprotetores/farmacologia , Neurite Óptica/patologia , Degeneração Retiniana/patologia , Adulto , Idoso , Animais , Encefalomielite Autoimune Experimental/patologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Células-Tronco Neurais/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Ratos , Ratos Wistar
19.
Mol Pharmacol ; 97(6): 355-364, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32241959

RESUMO

Voltage-gated potassium 11.1 (Kv11.1) channels play a critical role in repolarization of cardiomyocytes during the cardiac action potential (AP). Drug-mediated Kv11.1 blockade results in AP prolongation, which poses an increased risk of sudden cardiac death. Many drugs, like pentamidine, interfere with normal Kv11.1 forward trafficking and thus reduce functional Kv11.1 channel densities. Although class III antiarrhythmics, e.g., dofetilide, rescue congenital and acquired forward trafficking defects, this is of little use because of their simultaneous acute channel blocking effect. We aimed to test the ability of a combination of dofetilide plus LUF7244, a Kv11.1 allosteric modulator/activator, to rescue Kv11.1 trafficking and produce functional Kv11.1 current. LUF7244 treatment by itself did not disturb or rescue wild type (WT) or G601S-Kv11.1 trafficking, as shown by Western blot and immunofluorescence microcopy analysis. Pentamidine-decreased maturation of WT Kv11.1 levels was rescued by 10 µM dofetilide or 10 µM dofetilide + 5 µM LUF7244. In trafficking defective G601S-Kv11.1 cells, dofetilide (10 µM) or dofetilide + LUF7244 (10 + 5 µM) also restored Kv11.1 trafficking, as demonstrated by Western blot and immunofluorescence microscopy. LUF7244 (10 µM) increased IKv 11.1 despite the presence of dofetilide (1 µM) in WT Kv11.1 cells. In G601S-expressing cells, long-term treatment (24-48 hour) with LUF7244 (10 µM) and dofetilide (1 µM) increased IKv11.1 compared with nontreated or acutely treated cells. We conclude that dofetilide plus LUF7244 rescues Kv11.1 trafficking and produces functional IKv11.1 Thus, combined administration of LUF7244 and an IKv11.1 trafficking corrector could serve as a new pharmacological therapy of both congenital and drug-induced Kv11.1 trafficking defects. SIGNIFICANCE STATEMENT: Decreased levels of functional Kv11.1 potassium channel at the plasma membrane of cardiomyocytes prolongs action potential repolarization, which associates with cardiac arrhythmia. Defective forward trafficking of Kv11.1 channel protein is an important factor in acquired and congenital long QT syndrome. LUF7244 as a negative allosteric modulator/activator in combination with dofetilide corrected both congenital and acquired Kv11.1 trafficking defects, resulting in functional Kv11.1 current.


Assuntos
Antiarrítmicos/farmacologia , Canal de Potássio ERG1/efeitos dos fármacos , Compostos Orgânicos/farmacologia , Fenetilaminas/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Sulfonamidas/farmacologia , Potenciais de Ação/efeitos dos fármacos , Antiarrítmicos/química , Western Blotting , Simulação por Computador , Sinergismo Farmacológico , Canal de Potássio ERG1/fisiologia , Células HEK293 , Humanos , Microscopia de Fluorescência , Modelos Moleculares , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/fisiologia , Compostos Orgânicos/química , Fenetilaminas/química , Bloqueadores dos Canais de Potássio/química , Piridinas , Sulfonamidas/química
20.
Sci Rep ; 10(1): 4476, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32161292

RESUMO

Snake venom serine proteases (SVSPs) are complex and multifunctional enzymes, acting primarily on hemostasis. In this work, we report the hitherto unknown inhibitory effect of a SVSP, named collinein-1, isolated from the venom of Crotalus durissus collilineatus, on a cancer-relevant voltage-gated potassium channel (hEAG1). Among 12 voltage-gated ion channels tested, collinein-1 selectively inhibited hEAG1 currents, with a mechanism independent of its enzymatic activity. Corroboratively, we demonstrated that collinein-1 reduced the viability of human breast cancer cell line MCF7 (high expression of hEAG1), but does not affect the liver carcinoma and the non-tumorigenic epithelial breast cell lines (HepG2 and MCF10A, respectively), which present low expression of hEAG1. In order to obtain both functional and structural validation of this unexpected discovery, where an unusually large ligand acts as an inhibitor of an ion channel, a recombinant and catalytically inactive mutant of collinein-1 (His43Arg) was produced and found to preserve its capability to inhibit hEAG1. A molecular docking model was proposed in which Arg79 of the SVSP 99-loop interacts directly with the potassium selectivity filter of the hEAG1 channel.


Assuntos
Hemostasia , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio/metabolismo , Serina Proteases/toxicidade , Venenos de Serpentes/toxicidade , Sequência de Aminoácidos , Antineoplásicos/farmacologia , Catálise , Linhagem Celular , Desenho de Fármacos , Fenômenos Eletrofisiológicos , Canais de Potássio Éter-A-Go-Go/antagonistas & inibidores , Canais de Potássio Éter-A-Go-Go/química , Humanos , Conformação Molecular , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Bloqueadores dos Canais de Potássio/química , Canais de Potássio/química , Proteínas Recombinantes , Serina Proteases/química , Venenos de Serpentes/química , Relação Estrutura-Atividade
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