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voltage gated potassium channel

Satoshi Umemura
Primary aldosteronism (PA) is a heterogeneous group of disorders including both sporadic and familial forms (familial hyperaldosteronism type I, II and III). PA is the most frequent endocrine cause of secondary hypertension and associated with a higher rate of cardiovascular complications, compared with essential hypertension.Here I review the recent progress in understanding of the genetic and molecular mechanisms leading to autonomous aldosterone production in PA.Systematic screening detects primary aldosteronism in 5 to 10% of all patients with hypertension and in approximately 20% of patients with resistant hypertension...
September 2016: Journal of Hypertension
Pasquale Striano, Vincenzo Belcastro, Antonietta Coppola, Carlo Minetti, Salvatore Striano
INTRODUCTION: Despite optimal medical treatment, up to 30% of patients with epilepsy continue to experience recurrent seizures, and the challenge for new more efficacious and better-tolerated drugs is continuing. New antiepileptic drugs include the evolution of preexisting drugs and new compounds identified through the investigation of additional molecular targets, such as SV2A synaptic vesicle protein, voltage-gated potassium channels, ionotropic and metabotropic glutamate receptors, and gap junctions...
October 5, 2016: Clinical Neuropharmacology
Hung X Nguyen, Robert D Kirkton, Nenad Bursac
The ability to directly enhance electrical excitability of human cells is hampered by the lack of methods to efficiently overexpress large mammalian voltage-gated sodium channels (VGSC). Here we describe the use of small prokaryotic sodium channels (BacNav) to create de novo excitable human tissues and augment impaired action potential conduction in vitro. Lentiviral co-expression of specific BacNav orthologues, an inward-rectifying potassium channel, and connexin-43 in primary human fibroblasts from the heart, skin or brain yields actively conducting cells with customizable electrophysiological phenotypes...
October 18, 2016: Nature Communications
Jingying Gao, Tao Bai, Lele Ren, Yaqin Ding, Xiangqin Zhong, Hui Wang, Yangyan Guo, Jie Li, Yunfeng Liu, Yi Zhang
Uncarboxylated osteocalcin, a bone matrix protein, has been proposed to regulate glucose metabolism by increasing insulin secretion, improving insulin sensitivity and stimulating β cell proliferation. Our previous study also indicated that uncarboxylated osteocalcin stimulates insulin secretion by inhibiting voltage-gated potassium (KV) channels. The goal of this study is to further investigate the underlying mechanisms for the regulation of Kv channels and insulin secretion by uncarboxylated osteocalcin. Insulin secretion and Kv channel currents were examined by radioimmunoassay and patch-clamp technique, respectively...
October 14, 2016: Peptides
Bailin Cong, Yingmei Chai, Bo Wang, Shenghao Liu, Jihong Shen, Nengfei Wang, Quanqi Zhang, Xiaohang Huang
Potassium ion channels are one of the most diversely and widely distributed channels, which are involved in all kinds of physiological functions in both excitable and non-excitable cells. The expression of voltage-gated potassium ion (Kv) channels is highly variable according to the state of macrophages activation. Macrophages have an important function in innate immunity against intruding pathogens. They produce a variety of inflammatory and immunoactive molecules that modulate imflammatory responses. Here we show that blockade of K(+) channels by non-selective Kv channel inhibitor tetraethylammonium chloride (TEA), and 4-aminopyridine (4-AP) inhibited proinflammatory cytokines expression, cell proliferation, and reactive oxygen species (ROS) production in LPS-stimulated macrophages of Sea perch (Lateolabrax japonicas)...
October 12, 2016: Fish & Shellfish Immunology
Marivi Nabong Moen, Roar Fjær, El Hassan Hamdani, Jon K Laerdahl, Robin Johansen Menchini, Magnus Dehli Vigeland, Ying Sheng, Dag Erik Undlien, Bjørnar Hassel, Mustafa A Salih, Heba Y El Khashab, Kaja Kristine Selmer, Farrukh Abbas Chaudhry
Progressive myoclonus epilepsy is a heterogeneous group of disorders characterized by myoclonic and tonic-clonic seizures, ataxia and cognitive decline. We here present two affected brothers. At 9 months of age the elder brother developed ataxia and myoclonic jerks. In his second year he lost the ability to walk and talk, and he developed drug-resistant progressive myoclonus epilepsy. The cerebrospinal fluid level of glutamate was decreased while glutamine was increased. His younger brother manifested similar symptoms from 6 months of age...
October 14, 2016: Brain: a Journal of Neurology
Mark A Corbett, Susannah T Bellows, Melody Li, Renée Carroll, Silvana Micallef, Gemma L Carvill, Candace T Myers, Katherine B Howell, Snezana Maljevic, Holger Lerche, Elena V Gazina, Heather C Mefford, Melanie Bahlo, Samuel F Berkovic, Steven Petrou, Ingrid E Scheffer, Jozef Gecz
OBJECTIVE: To identify the genetic basis of a family segregating episodic ataxia, infantile seizures, and heterogeneous epilepsies and to study the phenotypic spectrum of KCNA2 mutations. METHODS: A family with 7 affected individuals over 3 generations underwent detailed phenotyping. Whole genome sequencing was performed on a mildly affected grandmother and her grandson with epileptic encephalopathy (EE). Segregating variants were filtered and prioritized based on functional annotations...
October 12, 2016: Neurology
Yibo Wang, Jiqing Guo, Laura L Perissinotti, James Lees-Miller, Guoqi Teng, Serdar Durdagi, Henry J Duff, Sergei Yu Noskov
Mutations that reduce inactivation of the voltage-gated Kv11.1 potassium channel (hERG) reduce binding for a number of blockers. State specific block of the inactivated state of hERG block may increase risks of drug-induced Torsade de pointes. In this study, molecular simulations of dofetilide binding to the previously developed and experimentally validated models of the hERG channel in open and open-inactivated states were combined with voltage-clamp experiments to unravel the mechanism(s) of state-dependent blockade...
October 12, 2016: Scientific Reports
Geoffrey W Abbott, Thomas A Jepps
Voltage-gated potassium (Kv) channels formed by Kv7 (KCNQ) α-subunits are recognized as crucial for vascular smooth muscle function, in addition to their established roles in the heart (Kv7.1) and the brain (Kv7.2-5). In vivo, Kv7 α-subunits are often regulated by KCNE subfamily ancillary (β) subunits. We investigated the effects of targeted germline Kcne4 deletion on mesenteric artery reactivity in adult male and female mice. Kcne4 deletion increased mesenteric artery contractility in response to α-adrenoceptor agonist methoxamine, and decreased responses to Kv7...
October 7, 2016: Journal of Vascular Research
Massimiliano Godani, Marco Zoccarato, Alessandro Beronio, Luigi Zuliani, Luana Benedetti, Bruno Giometto, Massimo Del Sette, Elisa Raggio, Roberta Baldi, Angela Vincent
BACKGROUND: The spectrum of autoimmune neurological diseases associated with voltage-gated potassium channel (VGKC)-complex antibodies (Abs) ranges from peripheral nerve disorders to limbic encephalitis. Recently, low titers of VGKC-complex Abs have also been reported in neurodegenerative disorders, but their clinical relevance is unknown. OBJECTIVE: The aim of the study was to explore the prevalence of VGKC-complex Abs in slow-progression motor neuron disease (MND)...
October 7, 2016: Neuro-degenerative Diseases
Juan Zhao, Rikard Blunck
Domains in macromolecular complexes are often considered structurally and functionally conserved while energetically coupled to each other. In the modular voltage-gated ion channels the central ion-conducting pore is surrounded by four voltage sensing domains (VSDs). Here, the energetic coupling is mediated by interactions between the S4-S5 linker, covalently linking the domains, and the proximal C-terminus. In order to characterize the intrinsic gating of the voltage sensing domain in the absence of the pore domain, the Shaker Kv channel was truncated after the 4(th) transmembrane helix S4 (Shaker-iVSD)...
October 6, 2016: ELife
Caroline M Cremonez, Mohitosh Maiti, Steve Peigneur, Juliana Silva Cassoli, Alexandre A A Dutra, Etienne Waelkens, Eveline Lescrinier, Piet Herdewijn, Maria Elena de Lima, Adriano M C Pimenta, Eliane C Arantes, Jan Tytgat
To date, several families of peptide toxins specifically interacting with ion channels in scorpion venom have been described. One of these families comprise peptide toxins (called KTxs), known to modulate potassium channels. Thus far, 202 KTxs have been reported, belonging to several subfamilies of KTxs (called α, β, γ, κ, δ, and λ-KTxs). Here we report on a previously described orphan toxin from Tityus serrulatus venom, named Ts11. We carried out an in-depth structure-function analysis combining 3D structure elucidation of Ts11 and electrophysiological characterization of the toxin...
September 30, 2016: Toxins
Jun Liu, Ping Hua, Li Hui, Li-Li Zhang, Zhen Hu, Ying-Wei Zhu
The objective of this study was to identify hub genes and pathways associated with hepatocellular carcinoma (HCC) by centrality analysis of a co-expression network. A co-expression network based on differentially expressed (DE) genes of HCC was constructed using the Differentially Co-expressed Genes and Links (DCGL) package. Centrality analyses, for centrality of degree, clustering coefficient, closeness, stress and betweenness for the co-expression network were performed to identify hub genes, and the hub genes were combined together to overcome inconsistent results...
October 2016: Experimental and Therapeutic Medicine
María de Guadalupe Chávez-López, Violeta Zúñiga-García, Julio Isael Pérez-Carreón, Arturo Avalos-Fuentes, Yesenia Escobar, Javier Camacho
Hepatocellular carcinoma (HCC) is a major cause of cancer death worldwide. HCC is usually asymptomatic at potential curative stages, and it has very poor prognosis if detected later. Thus, the identification of early biomarkers and novel therapies is essential to improve HCC patient survival. Ion channels have been proposed as potential tumor markers and therapeutic targets for several cancers including HCC. Especially, the ether à-go-go-1 (Eag1) voltage-gated potassium channel has been suggested as an early marker for HCC...
2016: Biologics: Targets & Therapy
Edvina Galié, Rosaria Renna, Domenico Plantone, Andrea Pace, Mirella Marino, Bruno Jandolo, Tatiana Koudriavtseva
Morvan's syndrome (MoS) is a rare, complex neurological disorder characterized by neuromyotonia, neuropsychiatric features, dysautonomia and neuropathic pain. The majority of MoS cases have a paraneoplastic aetiology, usually occurring prior to the diagnosis of the underlying tumour and showing improvement following its treatment. The present study reports the case of a 35-year-old Caucasian male patient who was diagnosed with stage IVA thymoma. Thymectomy, lung resection, diaphragmatic pleurectomy and pericardio-phrenectomy were performed 6 months after neoadjuvant chemotherapy...
October 2016: Oncology Letters
Aditi Khandekar, Steven Springer, Wei Wang, Stephanie Hicks, Carla J Weinheimer, Ramon Diaz-Trelles, Jeanne M Nerbonne, Stacey Rentschler
RATIONALE: Ventricular arrhythmias often arise from the Purkinje-myocyte junction and are a leading cause of sudden cardiac death. Notch activation reprograms cardiac myocytes to an "induced Purkinje-like" state characterized by prolonged action potential duration and expression of Purkinje enriched genes. OBJECTIVE: To understand the mechanism by which canonical Notch signaling causes action potential prolongation. METHODS AND RESULTS: We find that endogenous Purkinje cells have reduced peak K(+) current, Ito and IK,slow when compared with ventricular myocytes...
October 3, 2016: Circulation Research
Anjani Kumar Sharma, Manminder Kaur, Madhuparna Paul
Morvan's syndrome is a rare autoimmune disorder characterized by triad of peripheral nerve hyperexcitability, autonomic dysfunction, and central nervous system symptoms. Antibodies against contactin-associated protein-like 2 (CASPR2), a subtype of voltage-gated potassium channel (VGKC) complex, are found in a significant proportion of patients with Morvan's syndrome and are thought to play a key role in peripheral as well as central clinical manifestations. We report a patient of Morvan's syndrome with positive CASPR2-anti-VGKC antibody having syndrome of inappropriate antidiuretic hormone as a cause of persistent hyponatremia...
October 2016: Journal of Neurosciences in Rural Practice
Qing Li, Ting-Ting Tang, Feng Jiang, Rong Zhang, Miao Chen, Jun Yin, Yu-Qian Bao, Xiang Cheng, Cheng Hu, Wei-Ping Jia
AIM: KCNQ1 channel is a member of the voltage-gated potassium channel KQT-like subfamily. The KCNQ1 gene has recently been identified as a susceptibility locus for type 2 diabetes mellitus (T2DM). In the present study, we examined the effects of KCNQ1 variants on the therapeutic response to modified-release gliclazide (gliclazide MR) treatment in Chinese patients newly diagnosed with T2DM. METHODS: A total of 100 newly diagnosed T2DM patients without a history of any anti-diabetic medications were treated with gliclazide MR for 16 weeks, but 91 patients completed the entire study...
October 3, 2016: Acta Pharmacologica Sinica
Zhi-Gang Huang, Hao-Wen Liu, Zhen-Zhen Yan, Sheng Wang, Lu-Yang Wang, Jiu-Ping Ding
Large-conductance Ca(2+)- and voltage- activated potassium (MaxiK or BK) channels are composed of a pore-forming α subunit (Slo) and four types of auxiliary β subunits or just a pore-forming α subunit. Although multiple N-linked glycosylation sites in the extracellular loop of β subunits have been identified, very little is known about how glycosylation influences the structure and function of BK channels. Using a combination of site-directed mutagenesis, western blot and patch-clamp recordings, we demonstrated that three sites in the extracellular loop of β2 subunit are N-glycosylated (N-X-T/S at N88, N96 and N119)...
October 3, 2016: Channels
Seher Berzingi, Mackenzie Newman, Han-Gang Yu
BACKGROUND: Membrane depolarization is associated with breast cancer. Depolarization-activated voltage-gated ion channels are directly implicated in the initiation, proliferation, and metastasis of breast cancer. METHODS: In this study, the role of voltage-gated potassium and calcium ion channel modulation was explored in two different invasive ductal human carcinoma cell lines, MDA-MB-231 (triple-negative) and MCF7 (estrogen-receptor-positive). RESULTS: Resting membrane potential is more depolarized in MCF7 and MDA-MB-231 cells compared to normal human mammary epithelial cells...
2016: Cancer Cell International
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