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1.
Proc Natl Acad Sci U S A ; 121(12): e2315707121, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38489388

RESUMO

KCTD10 belongs to the KCTD (potassiumchannel tetramerization domain) family, many members of which are associated with neuropsychiatric disorders. However, the biological function underlying the association with brain disorders remains to be explored. Here, we reveal that Kctd10 is highly expressed in neuronal progenitors and layer V neurons throughout brain development. Kctd10 deficiency triggers abnormal proliferation and differentiation of neuronal progenitors, reduced deep-layer (especially layer V) neurons, increased upper-layer neurons, and lowered brain size. Mechanistically, we screened and identified a unique KCTD10-interacting protein, KCTD13, associated with neurodevelopmental disorders. KCTD10 mediated the ubiquitination-dependent degradation of KCTD13 and KCTD10 ablation resulted in a considerable increase of KCTD13 expression in the developing cortex. KCTD13 overexpression in neuronal progenitors led to reduced proliferation and abnormal cell distribution, mirroring KCTD10 deficiency. Notably, mice with brain-specific Kctd10 knockout exhibited obvious motor deficits. This study uncovers the physiological function of KCTD10 and provides unique insights into the pathogenesis of neurodevelopmental disorders.


Assuntos
Encefalopatias , Transtornos do Neurodesenvolvimento , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Animais , Camundongos , Proteínas/metabolismo , Encéfalo/metabolismo , Neurônios/metabolismo , Transtornos do Neurodesenvolvimento/genética , Encefalopatias/genética , Neurogênese/genética , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo
2.
Pharmacogenomics ; 25(3): 117-131, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38506312

RESUMO

Aim: Drug-induced long QT syndrome (diLQTS), an adverse effect of many drugs, can lead to sudden cardiac death. Candidate genetic variants in cardiac ion channels have been associated with diLQTS, but several limitations of previous studies hamper clinical utility. Materials & methods: Thus, the purpose of this study was to assess the associations of KCNE1-D85N, KCNE2-I57T and SCN5A-G615E with diLQTS in a large observational case-control study (6,083 self-reported white patients treated with 27 different high-risk QT-prolonging medications; 12.0% with diLQTS). Results: KCNE1-D85N significantly associated with diLQTS (adjusted odds ratio: 2.24 [95% CI: 1.35-3.58]; p = 0.001). Given low minor allele frequencies, the study had insufficient power to analyze KCNE2-I57T and SCN5A-G615E. Conclusion: KCNE1-D85N is a risk factor for diLQTS that should be considered in future clinical practice guidelines.


Some medications can lead to a condition called drug-induced long QT syndrome (diLQTS), which can be a serious abnormal heart rhythm in some patients. In our research, we explored three specific changes in DNA related to the electrical function of the heart (KCNE1-D85N, KCNE2-I57T, SCN5A-G615E) and their link to diLQTS. Our study revealed a connection between KCNE1-D85N and diLQTS. This study emphasized the importance of including KCNE1-D85N in the medical guidelines to help identify patients at risk of diLQTS. We were unable to identify the connection of KCNE2-I57T and SCN5A-G615E with diLQTS, due to a low number of carriers in the study.


Assuntos
Síndrome do QT Longo , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Humanos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/genética , Canais de Potássio de Abertura Dependente da Tensão da Membrana/efeitos adversos , Estudos de Casos e Controles , Síndrome do QT Longo/induzido quimicamente , Síndrome do QT Longo/genética , Fatores de Risco
3.
Circ Res ; 134(5): 529-546, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38348657

RESUMO

BACKGROUND: Mature endothelial cells (ECs) are heterogeneous, with subtypes defined by tissue origin and position within the vascular bed (ie, artery, capillary, vein, and lymphatic). How this heterogeneity is established during the development of the vascular system, especially arteriovenous specification of ECs, remains incompletely characterized. METHODS: We used droplet-based single-cell RNA sequencing and multiplexed error-robust fluorescence in situ hybridization to define EC and EC progenitor subtypes from E9.5, E12.5, and E15.5 mouse embryos. We used trajectory inference to analyze the specification of arterial ECs (aECs) and venous ECs (vECs) from EC progenitors. Network analysis identified candidate transcriptional regulators of arteriovenous differentiation, which we tested by CRISPR (clustered regularly interspaced short palindromic repeats) loss of function in human-induced pluripotent stem cells undergoing directed differentiation to aECs or vECs (human-induced pluripotent stem cell-aECs or human-induced pluripotent stem cell-vECs). RESULTS: From the single-cell transcriptomes of 7682 E9.5 to E15.5 ECs, we identified 19 EC subtypes, including Etv2+Bnip3+ EC progenitors. Spatial transcriptomic analysis of 15 448 ECs provided orthogonal validation of these EC subtypes and established their spatial distribution. Most embryonic ECs were grouped by their vascular-bed types, while ECs from the brain, heart, liver, and lung were grouped by their tissue origins. Arterial (Eln, Dkk2, Vegfc, and Egfl8), venous (Fam174b and Clec14a), and capillary (Kcne3) marker genes were identified. Compared with aECs, embryonic vECs and capillary ECs shared fewer markers than their adult counterparts. Early capillary ECs with venous characteristics functioned as a branch point for differentiation of aEC and vEC lineages. CONCLUSIONS: Our results provide a spatiotemporal map of embryonic EC heterogeneity at single-cell resolution and demonstrate that the diversity of ECs in the embryo arises from both tissue origin and vascular-bed position. Developing aECs and vECs share common venous-featured capillary precursors and are regulated by distinct transcriptional regulatory networks.


Assuntos
Células Endoteliais , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Adulto , Humanos , Animais , Camundongos , Hibridização in Situ Fluorescente , Artérias , Encéfalo , Veias
4.
Expert Opin Ther Targets ; 28(1-2): 67-82, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38316438

RESUMO

INTRODUCTION: Kv1.3 is the main voltage-gated potassium channel of leukocytes from both the innate and adaptive immune systems. Channel function is required for common processes such as Ca2+ signaling but also for cell-specific events. In this context, alterations in Kv1.3 are associated with multiple immune disorders. Excessive channel activity correlates with numerous autoimmune diseases, while reduced currents result in increased cancer prevalence and immunodeficiencies. AREAS COVERED: This review offers a general view of the role of Kv1.3 in every type of leukocyte. Moreover, diseases stemming from dysregulations of the channel are detailed, as well as current advances in their therapeutic research. EXPERT OPINION: Kv1.3 arises as a potential immune target in a variety of diseases. Several lines of research focused on channel modulation have yielded positive results. However, among the great variety of specific channel blockers, only one has reached clinical trials. Future investigations should focus on developing simpler administration routes for channel inhibitors to facilitate their entrance into clinical trials. Prospective Kv1.3-based treatments will ensure powerful therapies while minimizing undesired side effects.


Assuntos
Doenças Autoimunes , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Humanos , Estudos Prospectivos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/uso terapêutico , Doenças Autoimunes/tratamento farmacológico , Transdução de Sinais , Canal de Potássio Kv1.3 , Bloqueadores dos Canais de Potássio/farmacologia
5.
Oncol Res ; 32(3): 585-596, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38361755

RESUMO

The role of lncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) in colon cancer involves various tumorigenic processes and has been studied widely. However, the mechanism by which it promotes colon cancer remains unclear. Retroviral vector pSEB61 was retrofitted in established HCT116-siKCN and SW480-siKCN cells to silence KCNQ1OT1. Cellular proliferation was measured using CCK8 assay, and flow cytometry (FCM) detected cell cycle changes. RNA sequencing (RNA-Seq) analysis showed differentially expressed genes (DEGs). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were carried out to analyze enriched functions and signaling pathways. RT-qPCR, immunofluorescence, and western blotting were carried out to validate downstream gene expressions. The effects of tumorigenesis were evaluated in BALB/c nude mice by tumor xenografts. Our data revealed that the silencing of KCNQ1OT1 in HCT116 and SW480 cells slowed cell growth and decreased the number of cells in the G2/M phase. RNA-Seq analysis showed the data of DEGs enriched in various GO and KEGG pathways such as DNA replication and cell cycle. RT-qPCR, immunofluorescence, and western blotting confirmed downstream CCNE2 and PCNA gene expressions. HCT116-siKCN cells significantly suppressed tumorigenesis in BALB/c nude mice. Our study suggests that lncRNA KCNQ1OT1 may provide a promising therapeutic strategy for colon cancer.


Assuntos
Neoplasias do Colo , Canais de Potássio de Abertura Dependente da Tensão da Membrana , RNA Longo não Codificante , Animais , Humanos , Camundongos , Carcinogênese/genética , Proliferação de Células/genética , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Camundongos Nus , MicroRNAs/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Canais de Potássio de Abertura Dependente da Tensão da Membrana/genética , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo
6.
Elife ; 122024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38335126

RESUMO

The function of the smooth muscle cells lining the walls of mammalian systemic arteries and arterioles is to regulate the diameter of the vessels to control blood flow and blood pressure. Here, we describe an in silico model, which we call the 'Hernandez-Hernandez model', of electrical and Ca2+ signaling in arterial myocytes based on new experimental data indicating sex-specific differences in male and female arterial myocytes from murine resistance arteries. The model suggests the fundamental ionic mechanisms underlying membrane potential and intracellular Ca2+ signaling during the development of myogenic tone in arterial blood vessels. Although experimental data suggest that KV1.5 channel currents have similar amplitudes, kinetics, and voltage dependencies in male and female myocytes, simulations suggest that the KV1.5 current is the dominant current regulating membrane potential in male myocytes. In female cells, which have larger KV2.1 channel expression and longer time constants for activation than male myocytes, predictions from simulated female myocytes suggest that KV2.1 plays a primary role in the control of membrane potential. Over the physiological range of membrane potentials, the gating of a small number of voltage-gated K+ channels and L-type Ca2+ channels are predicted to drive sex-specific differences in intracellular Ca2+ and excitability. We also show that in an idealized computational model of a vessel, female arterial smooth muscle exhibits heightened sensitivity to commonly used Ca2+ channel blockers compared to male. In summary, we present a new model framework to investigate the potential sex-specific impact of antihypertensive drugs.


High blood pressure is a major risk factor for heart disease, which is one of the leading causes of death worldwide. While drugs are available to control blood pressure, male and female patients can respond differently to treatment. However, the biological mechanisms behind this sex difference are not fully understood. Blood pressure is controlled by cells lining the artery walls called smooth muscle cells which alter the width of blood vessels. On the surface of smooth muscle cells are potassium and calcium channels which control the cell's electrical activity. When calcium ions enter the cell via calcium channels, this generates an electrical signal that causes the smooth muscle to contract and narrow the blood vessel. Potassium ions then flood out of the cell via potassium channels to dampen the rise in electrical activity, causing the muscle to relax and widen the artery. There are various sub-types of potassium and calcium channels in smooth muscle cells. Here, Hernandez-Hernandez et al. set out to find how these channels differ between male and female mice, and whether these sex differences could alter the response to blood pressure medication. The team developed a computational model of a smooth muscle cell, incorporating data from laboratory experiments measuring differences in cells isolated from the arteries of male and female mice. The model predicted that the sub-types of potassium and calcium channels in smooth muscle cells varied between males and females, and how the channels impacted electrical activity also differed. For instance, the potassium channel Kv2.1 was found to have a greater role in controlling electrical activity in female mice, and this sex difference impacted blood vessel contraction. The model also predicted that female mice were more sensitive than males to calcium channel blockers, a drug commonly prescribed to treat high blood pressure. The findings by Hernandez-Hernandez et al. provide new insights into the biological mechanisms underlying sex differences in response to blood pressure medication. They also demonstrate how computational models can be used to predict the effects of drugs on different individuals. In the future, these predictions may help researchers to identify better, more personalized treatments for blood pressure.


Assuntos
Bloqueadores dos Canais de Cálcio , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Camundongos , Masculino , Feminino , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Bloqueadores dos Canais de Cálcio/metabolismo , Músculo Liso Vascular/metabolismo , Artérias/metabolismo , Pressão Sanguínea , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Cálcio/metabolismo , Mamíferos/metabolismo
7.
Int J Biol Macromol ; 257(Pt 1): 128464, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38043654

RESUMO

The voltage-gated potassium channel 1.6 (Kv1.6) plays a vital role in ocular neurovascular beds and exerts its modulatory functions via interaction with other proteins. However, the interactome and their potential roles remain unknown. Here, the global proteome landscape of the ophthalmic artery (OA) and neuroretina was mapped, followed by the determination of Kv1.6 interactome and validation of its functionality and cellular localization. Microfluorimetric analysis of intracellular [K+] and Western blot validated the native functionality and cellular expression of the recombinant Kv1.6 channel protein. A total of 54, 9 and 28 Kv1.6-interacting proteins were identified in the mouse OA and, retina of mouse and rat, respectively. The Kv1.6-protein partners in the OA, namely actin cytoplasmic 2, alpha-2-macroglobulin and apolipoprotein A-I, were implicated in the maintenance of blood vessel integrity by regulating integrin-mediated adhesion to extracellular matrix and Ca2+ flux. Many retinal protein interactors, particularly the ADP/ATP translocase 2 and cytoskeleton protein tubulin, were involved in endoplasmic reticulum stress response and cell viability. Three common interactors were found in all samples comprising heat shock cognate 71 kDa protein, Ig heavy constant gamma 1 and Kv1.6 channel. This foremost in-depth investigation enriched and identified the elusive Kv1.6 channel and, elucidated its complex interactome.


Assuntos
Canais de Potássio de Abertura Dependente da Tensão da Membrana , Camundongos , Ratos , Animais , Canais de Potássio de Abertura Dependente da Tensão da Membrana/genética , Canais de Potássio/metabolismo , Proteoma/metabolismo , Artéria Oftálmica/química , Artéria Oftálmica/metabolismo , Citoplasma/metabolismo
8.
Am J Physiol Cell Physiol ; 326(1): C74-C88, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-37982174

RESUMO

Diversity in the functional expression of ion channels contributes to the unique patterns of activity generated in visceral sensory A-type myelinated neurons versus C-type unmyelinated neurons in response to their natural stimuli. In the present study, Kv2 channels were identified as underlying a previously uncharacterized delayed rectifying potassium current expressed in both A- and C-type nodose ganglion neurons. Kv2.1 and 2.2 appear confined to the soma and initial segment of these sensory neurons; however, neither was identified in their central presynaptic terminals projecting onto relay neurons in the nucleus of the solitary tract (nTS). Kv2.1 and Kv2.2 were also not detected in the peripheral axons and sensory terminals in the aortic arch. Functionally, in nodose neuron somas, Kv2 currents exhibited frequency-dependent current inactivation and contributed to action potential repolarization in C-type neurons but not A-type neurons. Within the nTS, the block of Kv2 currents does not influence afferent presynaptic calcium influx or glutamate release in response to afferent activation, supporting our immunohistochemical observations. On the other hand, Kv2 channels contribute to membrane hyperpolarization and limit action potential discharge rate in second-order neurons. Together, these data demonstrate that Kv2 channels influence neuronal discharge within the vagal afferent-nTS circuit and indicate they may play a significant role in viscerosensory reflex function.NEW & NOTEWORTHY We demonstrate the expression and function of the voltage-gated delayed rectifier potassium channel Kv2 in vagal nodose neurons. Within sensory neurons, Kv2 channels limit the width of the broader C-type but not narrow A-type action potential. Within the nucleus of the solitary tract (nTS), the location of the vagal terminal field, Kv2 does not influence glutamate release. However, Kv2 limits the action potential discharge of nTS relay neurons. These data suggest a critical role for Kv2 in the vagal-nTS reflex arc.


Assuntos
Canais de Potássio de Abertura Dependente da Tensão da Membrana , Núcleo Solitário , Ratos , Animais , Núcleo Solitário/fisiologia , Ratos Sprague-Dawley , Neurônios/metabolismo , Glutamatos/metabolismo , Reflexo
9.
J Affect Disord ; 347: 399-405, 2024 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-38000475

RESUMO

BACKGROUND: Escitalopram can cause prolongation of the QT interval on the electrocardiogram (ECG). However, only some patients get pathological QTc prolongation in clinic. We investigated the influence of KCNQ1, KCNE1, and KCNH2 gene polymorphisms along with clinical factors on escitalopram-induced QTc prolongation. METHODS: A total of 713 patients prescribed escitalopram were identified and had at least one ECG recording in this retrospective study. 472 patients with two or more ECG data were divided into QTc prolongation (n = 119) and non-prolongation (n = 353) groups depending on the threshold change in QTc of 30 ms above baseline value (∆QTc ≥ 30 ms). 45 patients in the QTc prolongation group and 90 patients in the QTc non-prolongation group were genotyped for 43 single nucleotide polymorphisms (SNPs) of KCNQ1, KCNE1, and KCNH2 genes. RESULTS: Patients with QTc prolongation (∆QTc ≥ 30 ms) got higher escitalopram dose (10.3 mg) than patients without QTc prolongation (9.4 mg), although no significant relationship was found between QTc interval and escitalopram dose in the linear mixed model. Patients who were older/coronary disease/hypertension or carried with KCNE1 rs1805127 C allele, KCNE1 rs4817668 C allele, KCNH2 rs3807372 AG/GG genotype were significantly at risk for QTc prolongation (∆QTc ≥ 30 ms). Concomitant antipsychotic treatment was associated with a longer QTc interval. LIMITATIONS: A relatively small sample size and lack of the blood concentration of escitalopram restricted the accurate relationship between escitalopram dose and QTc interval. CONCLUSION: Our study revealed that KCNQ1, KCNE1, and KCNH2 gene polymorphisms along with clinical factors provide a complementary effect in escitalopram-induced QTc prolongation.


Assuntos
Síndrome do QT Longo , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Humanos , Escitalopram , Estudos Retrospectivos , Canal de Potássio KCNQ1/genética , Eletrocardiografia , Polimorfismo de Nucleotídeo Único , Síndrome do QT Longo/induzido quimicamente , Síndrome do QT Longo/genética , Canais de Potássio de Abertura Dependente da Tensão da Membrana/genética , Canais de Potássio de Abertura Dependente da Tensão da Membrana/efeitos adversos , Canal de Potássio ERG1/genética
10.
Neuropsychopharmacology ; 49(3): 551-560, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37660129

RESUMO

Dopaminergic signaling in the nucleus accumbens shell (NAc) regulates neuronal activity relevant to reward-related learning, including cocaine-associated behaviors. Although astrocytes respond to dopamine and cocaine with structural changes, the impact of dopamine and cocaine on astrocyte functional plasticity has not been widely studied. Specifically, behavioral implications of voltage-gated channel activity in the canonically non-excitable astrocytes are not known. We characterized potassium channel function in NAc astrocytes following exposure to exogenous dopamine or cocaine self-administration training under short (2 h/day) and extended (6 h/day) access schedules. Electrophysiological, Ca2+ imaging, mRNA, and mass spectrometry tools were used for molecular characterization. Behavioral effects were examined after NAc-targeted microinjections of channel antagonists and astroglial toxins. Exogenous dopamine increased activity of currents mediated by voltage-gated (Kv7) channels in NAc astrocytes. This was associated with a ~5-fold increase in expression of Kcnq2 transcript level in homogenized NAc micropunches. Matrix-assisted laser desorption/ionization mass spectrometry revealed increased NAc dopamine levels in extended access, relative to short access, rats. Kv7 inhibition selectively increased frequency and amplitude of astrocyte intracellular Ca2+ transients in NAc of extended access rats. Inhibition of Kv7 channels in the NAc attenuated cocaine-seeking in extended access rats only, an effect that was occluded by microinjection of the astrocyte metabolic poison, fluorocitrate. These results suggest that voltage-gated K+ channel signaling in NAc astrocytes is behaviorally relevant, support Kv7-mediated regulation of astrocyte Ca2+ signals, and propose novel mechanisms of neuroglial interactions relevant to drug use.


Assuntos
Cocaína , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Ratos , Animais , Astrócitos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/farmacologia , Ratos Sprague-Dawley , Dopamina/farmacologia , Núcleo Accumbens
11.
J Appl Toxicol ; 44(3): 391-399, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37786982

RESUMO

The regulation of membrane potential and the contractility of vascular smooth muscle cells (VSMCs) by voltage-dependent K+ (Kv) potassium channels are well-established. In this study, native VSMCs from rabbit coronary arteries were used to investigate the inhibitory effect of sertindole, an atypical antipsychotic agent, on Kv channels. Sertindole induced dose-dependent inhibition of Kv channels, with an IC50 of 3.13 ± 0.72 µM. Although sertindole did not cause a change in the steady-state activation curve, it did lead to a negative shift in the steady-state inactivation curve. The application of 1- or 2-Hz train pulses failed to alter the sertindole-induced inhibition of Kv channels, suggesting use-independent effects of the drug. The inhibitory response to sertindole was significantly diminished by pretreatment with a Kv1.5 inhibitor but not by Kv2.1 and Kv7 subtype inhibitors. These findings demonstrate the sertindole dose-dependent and use-independent inhibition of vascular Kv channels (mainly the Kv1.5 subtype) through a mechanism that involves altering steady-state inactivation curves. Therefore, the use of sertindole as an antipsychotic drug may have adverse effects on the cardiovascular system.


Assuntos
Antipsicóticos , Imidazóis , Indóis , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Animais , Coelhos , Vasos Coronários , Antipsicóticos/toxicidade , Canais de Potássio de Abertura Dependente da Tensão da Membrana/farmacologia , Bloqueadores dos Canais de Potássio/toxicidade , Miócitos de Músculo Liso
12.
Neuroscience ; 538: 68-79, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38157976

RESUMO

Inhibitory parvalbumin (PV) interneurons regulate the activity of neural circuits within brain regions involved in emotional processing, including the prefrontal cortex (PFC). Recently, rodent studies have implicated a stress-induced increase in prefrontal PV neuron activity in the development of anxiety behaviors, particularly in females. However, the mechanisms through which stress increases activity of prefrontal PV neurons remain unknown. The fast-spiking properties of PV neurons in part come from their expression of voltage-gated potassium (K+) ion channels, particularly Kv3.1 channels. We therefore suggest that stress-induced changes in Kv3.1 channels contribute to the appearance of an anxious phenotype following chronic stress in female mice. Here, we first showed that unpredictable chronic mild stress (UCMS) increased expression of Kv3.1 channels on prefrontal PV neurons in female mice, a potential mechanism underlying the previously observed hyperactivity of these neurons after stress. We then showed that female mice deficient in Kv3.1 channels displayed resilience to UCMS-induced anxiety-like behaviors. Altogether, our findings implicate Kv3.1 channels in the development of anxiety-like behaviors following UCMS, particularly in females, providing a novel mechanism to understand sex-specific vulnerabilities to stress-induced psychopathologies.


Assuntos
Canais de Potássio de Abertura Dependente da Tensão da Membrana , Masculino , Camundongos , Feminino , Animais , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Neurônios/metabolismo , Interneurônios/metabolismo , Encéfalo/metabolismo , Ansiedade/metabolismo , Canais de Potássio Shaw/metabolismo
13.
Sci Adv ; 9(49): eadj5539, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-38064553

RESUMO

Eukaryotic voltage-gated K+ channels have been extensively studied, but the structural bases for some of their most salient functional features remain to be established. C-type inactivation, for example, is an auto-inhibitory mechanism that confers temporal resolution to their signal-firing activity. In a recent breakthrough, studies of a mutant of Shaker that is prone to inactivate indicated that this process entails a dilation of the selectivity filter, the narrowest part of the ion conduction pathway. Here, we report an atomic-resolution cryo-electron microscopy structure that demonstrates that the wild-type channel can also adopt this dilated state. All-atom simulations corroborate this conformation is congruent with the electrophysiological characteristics of the C-type inactivated state, namely, residual K+ conductance and altered ion specificity, and help rationalize why inactivation is accelerated or impeded by certain mutations. In summary, this study establishes the molecular basis for an important self-regulatory mechanism in eukaryotic K+ channels, laying a solid foundation for further studies.


Assuntos
Ativação do Canal Iônico , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Microscopia Crioeletrônica , Dilatação , Ativação do Canal Iônico/fisiologia
14.
J Clin Neuromuscul Dis ; 25(2): 94-106, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37962197

RESUMO

OBJECTIVES: Isaac syndrome (IS) is a condition characterized by peripheral nerve hyperexcitability caused by voltage-gated potassium channel (VGKC)-complex antibodies. Muscle twitching, stiffness, hypertrophy, and dysautonomic characteristics, such as hyperhidrosis, are common manifestations. The syndrome can be autoimmune or paraneoplastic, with thymoma being a common cause of paraneoplastic IS. Furthermore, this condition could be handed down from one generation to another. However, there is limited information regarding outcomes, relapses, associated syndromes, associated malignancies (other than thymoma), and treatment options. Despite its rarity, there remains a need for effective management strategies for patients with IS. To address this gap, we conducted a systematic review to summarize the most common and effective treatments of IS in immunomodulatory agents and symptomatic medications, as well as to describe outcomes, relapses, and associated malignancies. Altogether, this review serves to guide clinical practice recommendations for IS and highlight areas for further research. METHODS: We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol to conduct a systematic review of cases reposted through the PubMed and Google Scholar databases. The terms "Isaac Syndrome" and "Acquired Neuromyotonia" were used. The Joanna Briggs Institute's critical appraisal tool was used to evaluate the quality of the included studies. RESULTS: We identified 61 case reports and 4 case series, comprising a total of 70 patients with IS (mean age at onset: 42.5 ± 18 years, and 69% were males). Fourteen cases reported relapses. Thymoma was the most common malignancy associated with IS, followed by lymphoma. Among various serum antibodies, voltage-gated potassium channel-complex antibodies were the most reported antibodies elevated in IS (reported in 38 patients and elevated in 21 patients [55.2%]), followed by acetylcholine ganglionic receptor antibodies, which were reported in 30% of patients (n = 21) and were elevated in 5 cases. The most common electromyography findings were myokymic discharges (n = 22), followed by fasciculations (n = 21) and neuromyotonia (n = 19). For treatment, combining anticonvulsants such as carbamazepine with immunotherapy therapy showed the best results in controlling the symptoms. Among immunotherapy therapies, the combination of plasma exchange plus intravenous high-dose steroids achieved the best results in the acute treatment of IS ([n = 6], with improvement noted in 83.3% [n = 5] of cases). Among the symptomatic treatments with anticonvulsants, carbamazepine was the most efficacious anticonvulsant in treatment of IS, with an average effective dosing of 480 mg/day (carbamazepine was used in 32.3% of acute treatment strategies [n = 23], with improvement noted in 73.9% [n = 17] of cases). CONCLUSIONS: IS a rare neuromuscular syndrome that tends to affect middle-aged men. These patients should be screened for thymoma and other malignancies such as lymphomas. The management of IS symptoms can be challenging, but based on our review, the combination of multiple immunosuppressives such as IV steroids and plasmapheresis with anticonvulsants such as carbamazepine seems to achieve the best results.


Assuntos
Síndrome de Isaacs , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Timoma , Neoplasias do Timo , Masculino , Pessoa de Meia-Idade , Humanos , Feminino , Síndrome de Isaacs/diagnóstico , Síndrome de Isaacs/terapia , Timoma/complicações , Timoma/terapia , Anticonvulsivantes/uso terapêutico , Neoplasias do Timo/complicações , Neoplasias do Timo/diagnóstico , Neoplasias do Timo/terapia , Autoanticorpos , Carbamazepina , Receptores Colinérgicos , Esteroides , Recidiva
15.
Proc Natl Acad Sci U S A ; 120(42): e2220029120, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37812700

RESUMO

Voltage-gated potassium channels (Kv) are tetrameric membrane proteins that provide a highly selective pathway for potassium ions (K+) to diffuse across a hydrophobic cell membrane. These unique voltage-gated cation channels detect changes in membrane potential and, upon activation, help to return the depolarized cell to a resting state during the repolarization stage of each action potential. The Kv3 family of potassium channels is characterized by a high activation potential and rapid kinetics, which play a crucial role for the fast-spiking neuronal phenotype. Mutations in the Kv3.1 channel have been shown to have implications in various neurological diseases like epilepsy and Alzheimer's disease. Moreover, disruptions in neuronal circuitry involving Kv3.1 have been correlated with negative symptoms of schizophrenia. Here, we report the discovery of a novel positive modulator of Kv3.1, investigate its biophysical properties, and determine the cryo-EM structure of the compound in complex with Kv3.1. Structural analysis reveals the molecular determinants of positive modulation in Kv3.1 channels by this class of compounds and provides additional opportunities for rational drug design for the treatment of associated neurological disorders.


Assuntos
Neurônios , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Humanos , Neurônios/metabolismo , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Canais de Potássio/metabolismo , Potenciais de Ação/fisiologia , Proteínas de Membrana/metabolismo
16.
J Neurophysiol ; 130(5): 1265-1281, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37820016

RESUMO

After rostral spinal cord injury (SCI) of lampreys, the descending axons of injured (axotomized) reticulospinal (RS) neurons regenerate and locomotor function gradually recovers. Our previous studies indicated that relative to uninjured lamprey RS neurons, injured RS neurons display several dramatic changes in their biophysical properties, called the "injury phenotype." In the present study, at the onset of applied depolarizing current pulses for membrane potentials below as well as above threshold for action potentials (APs), injured RS neurons displayed a transient depolarization consisting of an initial depolarizing component followed by a delayed repolarizing component. In contrast, for uninjured neurons the transient depolarization was mostly only evident at suprathreshold voltages when APs were blocked. For injured RS neurons, the delayed repolarizing component resisted depolarization to threshold and made these neurons less excitable than uninjured RS neurons. After block of voltage-gated sodium and calcium channels for injured RS neurons, the transient depolarization was still present. After a further block of voltage-gated potassium channels, the delayed repolarizing component was abolished or significantly reduced, with little or no effect on the initial depolarizing component. Voltage-clamp experiments indicated that the delayed repolarizing component was due to a noninactivating outward-rectifying potassium channel whose conductance (gK) was significantly larger for injured RS neurons compared to that for uninjured neurons. Thus, SCI results in an increase in gK and other changes in the biophysical properties of injured lamprey RS neurons that lead to a reduction in excitability, which is proposed to create an intracellular environment that supports axonal regeneration.NEW & NOTEWORTHY After spinal cord injury (SCI), lamprey reticulospinal (RS) neurons responded to subthreshold depolarizing current pulses with a transient depolarization, which included an initial depolarization that was due to passive channels followed by a delayed repolarization that was mediated by voltage-gated potassium channels. The conductance of these channels (gK) was significantly increased for RS neurons after SCI and contributed to a reduction in excitability, which is expected to provide supportive conditions for subsequent axonal regeneration.


Assuntos
Canais de Potássio de Abertura Dependente da Tensão da Membrana , Traumatismos da Medula Espinal , Animais , Canais de Potássio/fisiologia , Neurônios/fisiologia , Potenciais da Membrana/fisiologia , Lampreias , Medula Espinal
17.
Mol Psychiatry ; 28(9): 3994-4010, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37833406

RESUMO

The pathogenesis of schizophrenia is believed to involve combined dysfunctions of many proteins including microtubule-associated protein 6 (MAP6) and Kv3.1 voltage-gated K+ (Kv) channel, but their relationship and functions in behavioral regulation are often not known. Here we report that MAP6 stabilizes Kv3.1 channels in parvalbumin-positive (PV+ ) fast-spiking GABAergic interneurons, regulating behavior. MAP6-/- and Kv3.1-/- mice display similar hyperactivity and avoidance reduction. Their proteins colocalize in PV+ interneurons and MAP6 deletion markedly reduces Kv3.1 protein level. We further show that two microtubule-binding modules of MAP6 bind the Kv3.1 tetramerization domain with high affinity, maintaining the channel level in both neuronal soma and axons. MAP6 knockdown by AAV-shRNA in the amygdala or the hippocampus reduces avoidance or causes hyperactivity and recognition memory deficit, respectively, through elevating projection neuron activity. Finally, knocking down Kv3.1 or disrupting the MAP6-Kv3.1 binding in these brain regions causes avoidance reduction and hyperactivity, consistent with the effects of MAP6 knockdown. Thus, disrupting this conserved cytoskeleton-membrane interaction in fast-spiking neurons causes different degrees of functional vulnerability in various neural circuits.


Assuntos
Neurônios , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Camundongos , Animais , Neurônios/metabolismo , Canais de Potássio de Abertura Dependente da Tensão da Membrana/farmacologia , Citoesqueleto/metabolismo , Microtúbulos/metabolismo , Emoções , Canais de Potássio Shaw/metabolismo
19.
Channels (Austin) ; 17(1): 2253104, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37695839

RESUMO

The voltage-gated potassium channel KV1.3 is an important therapeutic target for the treatment of autoimmune and neuroinflammatory diseases. The recent structures of KV1.3, Shaker-IR (wild-type and inactivating W434F mutant) and an inactivating mutant of rat KV1.2-KV2.1 paddle chimera (KVChim-W362F+S367T+V377T) reveal that the transition of voltage-gated potassium channels from the open-conducting conformation into the non-conducting inactivated conformation involves the rupture of a key intra-subunit hydrogen bond that tethers the selectivity filter to the pore helix. Breakage of this bond allows the side chains of residues at the external end of the selectivity filter (Tyr447 and Asp449 in KV1.3) to rotate outwards, dilating the outer pore and disrupting ion permeation. Binding of the peptide dalazatide (ShK-186) and an antibody-ShK fusion to the external vestibule of KV1.3 narrows and stabilizes the selectivity filter in the open-conducting conformation, although K+ efflux is blocked by the peptide occluding the pore through the interaction of ShK-Lys22 with the backbone carbonyl of KV1.3-Tyr447 in the selectivity filter. Electrophysiological studies on ShK and the closely-related peptide HmK show that ShK blocks KV1.3 with significantly higher potency, even though molecular dynamics simulations show that ShK is more flexible than HmK. Binding of the anti-KV1.3 nanobody A0194009G09 to the turret and residues in the external loops of the voltage-sensing domain enhances the dilation of the outer selectivity filter in an exaggerated inactivated conformation. These studies lay the foundation to further define the mechanism of slow inactivation in KV channels and can help guide the development of future KV1.3-targeted immuno-therapeutics.


Assuntos
Simulação de Dinâmica Molecular , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Animais , Ratos , Transporte Biológico , Linhagem Celular , Conformação Molecular
20.
Eur J Pharmacol ; 957: 176005, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37611842

RESUMO

Lurasidone is a second-generation antipsychotic drug used to treat schizophrenia, mania, and bipolar disorder. The drug is an antagonist of the 5-HT2A and D2 receptors. No effect of lurasidone on the voltage-gated K+ (Kv) channels has yet been identified. Here, we show that lurasidone inhibits the vascular Kv channels of rabbit coronary arterial smooth muscle cells in a dose-dependent manner with an IC50 of 1.88 ± 0.21 µM and a Hill coefficient of 0.98 ± 0.09. Although lurasidone (3 µM) did not affect the activation kinetics, the drug negatively shifted the inactivation curve, suggesting that the drug interacted with the voltage sensors of Kv channels. Application of 1 or 2 Hz train steps in the presence of lurasidone significantly increased Kv current inhibition. The recovery time after channel inactivation increased in the presence of lurasidone. These results suggest that the inhibitory action of lurasidone is use (state)-dependent. Pretreatment with a Kv 1.5 subtype inhibitor effectively reduced the inhibitory effect of lurasidone. However, the inhibitory effect on Kv channels did not markedly change after pretreatment with a Kv 2.1 or a Kv7 subtype inhibitor. In summary, lurasidone inhibits vascular Kv channels (primarily the Kv1.5 subtype) in a concentration- and use (state)-dependent manner by shifting the steady-state inactivation curve.


Assuntos
Antipsicóticos , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Animais , Coelhos , Cloridrato de Lurasidona/farmacologia , Antipsicóticos/farmacologia , Vasos Coronários , Miócitos de Músculo Liso
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