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HL-1 cells; L-type calcium channels; Calcium regulation Células HL-1; Canales de calcio tipo L; Regulación del calcio Cel·lules HL-1; Canals de calci tipus L; Regulació del calci MicroRNAs (miRNAs) participate in atrial remodeling and atrial fibrillation (AF) promotion. We determined the circulating miRNA profile in patients with AF and heart failure with reduced ejection fraction (HFrEF), and its potential role in promoting the arrhythmia. In plasma of 98 patients with HFrEF (49 with AF and 49 in sinus rhythm, SR), differential miRNA expression was determined by high-throughput microarray analysis followed by replication of selected candidates. Validated miRNAs were determined in human atrial samples, and potential arrhythmogenic mechanisms studied in HL-1 cells. Circulating miR-199a-5p and miR-22-5p were significantly increased in HFrEF patients with AF versus those with HFrEF in SR. Both miRNAs, but particularly miR-199a-5p, were increased in atrial samples of patients with AF. Overexpression of both miRNAs in HL-1 cells resulted in decreased protein levels of L-type Ca2+ channel, NCX and connexin-40, leading to lower basal intracellular Ca2+ levels, fewer inward currents, a moderate reduction in Ca2+ buffering post-caffeine exposure, and a deficient cell-to-cell communication. In conclusion, circulating miR-199a-5p and miR-22-5p are higher in HFrEF patients with AF, with similar findings in human atrial samples of AF patients. Cells exposed to both miRNAs exhibited altered Ca2+ handling and defective cell-to-cell communication, both findings being potential arrhythmogenic mechanisms. This work was funded by the following grants, awarded to B.B.: Sociedad Española de Cardiología, Sección de Arritmias y Electrofisiología 2012; Sociedad Española de Cardiología, Sección de Insuficiencia Cardíaca 2013; Fondo Investigación Sanitaria (FIS)—Instituto Carlos III 2013 (PI13/01830); and Societat Catalana de Cardiologia 2016. Awarded to K.W.A-A. and S.R.: British Heart Foundation (BHF) Intermediate Research Fellowship. Awarded to J.M.F.F.: grant from the Spanish Ministry of Science and Innovation (RTI2018-094809-B-I00). “María de Maeztu” Programme for Units of Excellence in R&D to the Departament de Ciències Experimentals i de la Salut (MDM-2014-0370) and FEDER (Fondo Europeo de Desarrollo Regional) also contributed to this work.

The CACNA1A gene encodes the pore-forming α1A subunit of the voltage-gated CaV2.1 Ca2+ channel, essential in neurotransmission, especially in Purkinje cells. Mutations in CACNA1A result in great clinical heterogeneity with progressive symptoms, paroxysmal events or both. During infancy, clinical and neuroimaging findings may be unspecific, and no dysmorphic features have been reported. We present the clinical, radiological and evolutionary features of three patients with congenital ataxia, one of them carrying a new variant. We report the structural localization of variants and their expected functional consequences. There was an improvement in cerebellar syndrome over time despite a cerebellar atrophy progression, inconsistent response to acetazolamide and positive response to methylphenidate. The patients shared distinctive facial gestalt: oval face, prominent forehead, hypertelorism, downslanting palpebral fissures and narrow nasal bridge. The two α1A affected residues are fully conserved throughout evolution and among the whole human CaV channel family. They contribute to the channel pore and the voltage sensor segment. According to structural data analysis and available functional characterization, they are expected to exert gain- (F1394L) and loss-of-function (R1664Q/R1669Q) effect, respectively. Among the CACNA1A-related phenotypes, our results suggest that non-progressive congenital ataxia is associated with developmental delay and dysmorphic features, constituting a recognizable syndromic neurodevelopmental disorder. This work was funded by the Spanish Ministry of Health, Consumer Affairs and Social Welfare, the Spanish Ministry of Science and Innovation, the State Research Agency (AEI, Agencia Estatal de Investigación), and FEDER Funds (Fondo Europeo de Desarrollo Regional): Grants RTI2018-094809-B-I00 to J.M.F.F. and CEX2018-000792-M through the “María de Maeztu” Programme for Units of Excellence in R&D to “Departament de Ciències Experimentals i de la Salut”. M.S. is supported by the Generalitat de Catalunya (PERIS SLT008/18/00194) and National Grant PI17/00101 from the National R&D&I Plan, cofinanced by the Instituto de Salud Carlos III (Subdirectorate-General for Evaluation and Promotion of Health Research) and FEDER (European Regional Development Fund).

Mitochondria play key roles in ATP supply, calcium homeostasis, redox balance control and apoptosis, which in neurons are fundamental for neurotransmission and to allow synaptic plasticity. Their functional integrity is maintained by mitostasis, a process that involves mitochondrial transport, anchoring, fusion and fission processes regulated by different signaling pathways but mainly by the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). PGC-1α also favors Ca2+ homeostasis, reduces oxidative stress, modulates inflammatory processes and mobilizes mitochondria to where they are needed. To achieve their functions, mitochondria are tightly connected to the endoplasmic reticulum (ER) through specialized structures of the ER termed mitochondria-associated membranes (MAMs), which facilitate the communication between these two organelles mainly to aim Ca2+ buffering. Alterations in mitochondrial activity enhance reactive oxygen species (ROS) production, disturbing the physiological metabolism and causing cell damage. Furthermore, cytosolic Ca2+ overload results in an increase in mitochondrial Ca2+, resulting in mitochondrial dysfunction and the induction of mitochondrial permeability transition pore (mPTP) opening, leading to mitochondrial swelling and cell death through apoptosis as demonstrated in several neuropathologies. In summary, mitochondrial homeostasis is critical to maintain neuronal function; in fact, their regulation aims to improve neuronal viability and to protect against aging and neurodegenerative diseases. This work was supported by the Spanish Ministry of Science and Innovation and FEDER Funds through grants SAF2017-83372-R (FJM); RTI2018-094809-B-I00 (JMFF); PID2019-106755RB-I00 (RV); and through the “María de Maeztu” Programme for Units of Excellence in R&D (award CEX2018-000792-M).

Human mutations in the CACNA1A gene that encodes the pore-forming α1A subunit of the voltage-gated CaV2.1 (P/Q-type) Ca2+ channel cause multiple neurological disorders including sporadic and familial hemiplegic migraine, as well as cerebellar pathologies such as episodic ataxia, progressive ataxia, and early-onset cerebellar syndrome consistent with the definition of congenital ataxia (CA), with presentation before the age of 2 years. Such a pathological role is in accordance with the physiological relevance of CaV2.1 in neuronal tissue, especially in the cerebellum. This review deals with the report of the main clinical features defining CA, along with the presentation of an increasing number of CACNA1A genetic variants linked to this severe cerebellar disorder in the context of Ca2+ homeostasis alteration. Moreover, the review describes each pathological mutation according to structural location and known molecular and cellular functional effects in both heterologous expression systems and animal models. In view of this information in correlation with the clinical phenotype, we take into consideration different pathomechanisms underlying the observed motor dysfunction in CA patients carrying CACNA1A mutations. Present therapeutic management in CA and options for the development of future personalized treatment based on CaV2.1 dysfunction are also discussed. This work was funded by the Spanish Ministry of Science and Innovation, the State Research Agency (AEI, Agencia Estatal de Investigación), and FEDER Funds (Fondo Europeo de Desarrollo Regional): Grants RTI2018-094809-B-I00 to J.M.F.F. and CEX2018-000792-M through the “María de Maeztu” Programme for Units of Excellence in R&D to “Departament de Ciències Experimentals i de la Salut”. M.S. is supported by the Generalitat de Catalunya (PERIS SLT008/18/00194) and National Grant PI17/00101 from the National R&D&I Plan, cofinanced by the Instituto de Salud Carlos III (Subdirectorate-General for Evaluation and Promotion of Health Research) and European Regional Development Fund. M.I.-S. holds a “Juan de la Cierva-Incorporación” Fellowship funded by the Spanish Ministry of Science and Innovation.

Background Mutations in the CACNA1A gene, encoding the pore-forming CaV2.1 (P/Q-type) channel α1A subunit, localized at presynaptic terminals of brain and cerebellar neurons, result in clinically variable neurological disorders including hemiplegic migraine (HM) and episodic or progressive adult-onset ataxia (EA2, SCA6). Most recently, CACNA1A mutations have been identified in patients with nonprogressive congenital ataxia (NPCA). Methods We performed targeted resequencing of known genes involved in cerebellar dysfunction, in 48 patients with congenital or early onset ataxia associated with cerebellar and/or vermis atrophy. Results De novo missense mutations of CACNA1A were found in four patients (4/48, ∼8.3%). Three of them developed migraine before or after the onset of ataxia. Seizures were present in half of the cases. Conclusion Our results expand the clinical and mutational spectrum of CACNA1A -related phenotype in childhood and suggest that CACNA1A screening should be implemented in this subgroup of ataxias.

Benign paroxysmal torticollis of infancy (BPTI) is a rare paroxysmal disorder characterized by recurrent episodes of head tilt and accompanying general symptoms which remit spontaneously. The rare association with gain-of-function CACNA1A mutations, similar to hemiplegic migraine, has been reported. We report here two new BPTI patients from the same family carrying a heterozygous mutation in the CACNA1A gene leading to the change p.Glu533Lys. Functional analysis revealed that this mutation induces a loss of channel function due to impaired gating by voltage and much lower current density. Our data suggest that BPTI, a periodic syndrome commonly considered a migraine precursor, constitutes an age-specific manifestation of defective neuronal calcium channel activity.

Opening of intermediate-conductance calcium-activated potassium channels (KCa3.1) produces membrane hyperpolarization in the vascular endothelium. Here, we studied the ability of two new KCa3.1-selective positive-gating modulators, SKA-111 and SKA-121, to (1) evoke porcine endothelial cell KCa3.1 membrane hyperpolarization, (2) induce endothelium-dependent and, particularly, endothelium-derived hyperpolarization (EDH)-type relaxation in porcine coronary arteries (PCA) and (3) influence coronary artery tone in isolated rat hearts. In whole-cell patch-clamp experiments on endothelial cells of PCA (PCAEC), KCa currents evoked by bradykinin (BK) were potentiated ≈7-fold by either SKA-111 or SKA-121 (both at 1 μM) and were blocked by a KCa3.1 blocker, TRAM-34. In membrane potential measurements, SKA-111 and SKA-121 augmented bradykinin-induced hyperpolarization. Isometric tension measurements in large- and small-calibre PCA showed that SKA-111 and SKA-121 potentiated endothelium-dependent relaxation with intact NO synthesis and EDH-type relaxation to BK by ≈2-fold. Potentiation of the BK response was prevented by KCa3.1 inhibition. In Langendorff-perfused rat hearts, SKA-111 potentiated coronary vasodilation elicited by BK. In conclusion, our data show that positive-gating modulation of KCa3.1 channels improves BK-induced membrane hyperpolarization and endothelium-dependent relaxation in small and large PCA as well as in the coronary circulation of rats. Positive-gating modulators of KCa3.1 could be therapeutically useful to improve coronary blood flow and counteract impaired coronary endothelial dysfunction in cardiovascular disease., This work was supported by the Deutsche Forschungsgemeinschaft [KO1899/11-1 to RK]; the Danish Heart Foundation (to RK and US), European Community [FP7-PEOPLE Project 321721]; Department of Industry & Innovation, Government of Aragon [GIPASC-B105 to ALGO, RK, AOV]; and the Fondo de Investigación Sanitaria, Instituto de Salud Carlos III [RIC RD12/0042/0014 Red HERACLES, to RK]. This study received Grant from the Government of Aragón [GA E-102 to JAG, MDD, RB]; Grant of the Spanish Ministry of Economy and Competitiveness plus FEDER Funds [no SAF2012-31631 to LR and SAF2012-31089 to JMFF]; Grants from the National Institute of Neurological Disorders and Stroke [R21NS072585 to HW]; and from the National Heart, Lung & Blood Institute T32 Training Program in Basic and Translational Cardiovascular Science [T32HL086350to NC].

Familial hemiplegic migraine (FHM)-causing mutations in the gene encoding the P/Q Ca 2+ channel α 1A subunit ( CACNA1A ) locate to the pore and voltage sensor regions and normally involve gain-of-channel function. We now report on a mutation identified in the first intracellular loop of CACNA1A (α 1A(A454T) ) that does not cause FHM but is associated with the absence of sensorimotor symptoms in a migraine with aura pedigree. α 1A(A454T) channels showed weakened regulation of voltage-dependent steady-state inactivation by Ca V β subunits. More interestingy, A454T mutation suppressed P/Q channel modulation by syntaxin 1A or SNAP-25 and decreased exocytosis. Our findings reveal the importance of I-II loop structural integrity in the functional interaction between P/Q channel and proteins of the vesicle-docking/fusion machinery, and that genetic variation in CACNA1A may be not only a cause but also a modifier of migraine phenotype.

Disorders of water balance are among the most common and morbid of the electrolyte disturbances, and are reflected clinically as abnormalities in the serum sodium concentration. The transient receptor potential vanilloid 4 (TRPV4) channel is postulated to comprise an element of the central tonicity-sensing mechanism in the mammalian hypothalamus, and is activated by hypotonic stress in vitro. A nonsynonymous polymorphism in the TRPV4 gene gives rise to a Pro-to-Ser substitution at residue 19. We show that this polymorphism is significantly associated with serum sodium concentration and with hyponatremia (serum sodium concentration ≤135 mEq/L) in 2 non-Hispanic Caucasian male populations; in addition, mean serum sodium concentration is lower among subjects with the TRPV4 P19S allele relative to the wild-type allele. Subjects with the minor allele were 2.4−6.4 times as likely to exhibit hyponatremia as subjects without the minor allele (after inclusion of key covariates). Consistent with these observations, a human TRPV4 channel mutated to incorporate the TRPV4 P19S polymorphism showed diminished response to hypotonic stress (relative to the wild-type channel) and to the osmotransducing lipid epoxyeicosatrienoic acid in heterologous expression studies. These data suggest that this polymorphism affects TRPV4 function in vivo and likely influences systemic water balance on a population-wide basis.

Migraine is a common neurological disorder with a complex inheritance pattern. Mutations in genes encoding proteins that are involved in ion transport across the neuronal membrane have been linked to rare monogenic variants of migraine. These or other related genes and proteins are also candidates to be involved in the inherited predisposition to the more common forms of migraine without aura (MO) or migraine with aura (MA). One of these proteins, syntaxin 1A, encoded by the STX1A gene, is a key molecule in ion channel regulation and synaptic exocytosis. We assessed the contribution of STX1A to migraine by analyzing three SNPs that cover the entire gene (rs6951030–rs941298–rs4363087), in a case–control association study in 210 migraine patients (102 MO, 86 MA, 22 hemiplegic migraine) and 210 sex-matched unrelated controls. The single-marker analysis revealed significant differences in both allele frequencies (P = 0.0087, OR = 1.48) and genotype distributions (P = 0.0133) of the rs941298 SNP between migraineurs and controls, with an overrepresentation of T-allele carriers in the migraine sample (OR = 1.78). We subsequently performed a haplotype-based analysis and observed evidence of an overrepresentation of the A–T–G (rs6951030–rs941298–rs4363087) allelic combination in migraine patients and an increased frequency of carriers of this risk haplotype (P = 0.008, OR = 1.71). These differences remained significant when patients were subdivided into MO and MA. When the control series was enlarged for rs941298, we confirmed the association only with the whole migraine group.

We report a patient with typical features of episodic ataxia type 2 (EA2) but with onset in the sixth decade and associated interictal hand dystonia. He was found to bear the novel heterozygous missense mutation p.Gly638Asp (c.1913G > A) in the CACNA1A gene. Functional analysis of the mutation on P/Q channels expressed in HEK 293 cells revealed a reduction of Ca2+ current densities, a left-shift in the apparent reversal potential, the slowing of inactivation kinetics and the increase in the rate of current recovery from inactivation. These results are consistent with a decrease in Ca2+ permeability through mutant P/Q channels. To our knowledge, this is just the second patient with late onset EA2 linked to a CACNA1A mutation and the first to carry a loss-of-function missense mutation., This study was supported by the Spanish Ministry of Education and Science (SAF2003-04704, SAF2006-13893-C02-01, SAF2006-13893-C02-02, SAF2006-4973), Fondo de Investigación Sanitaria (red HERACLES), Fundació La Marató de TV3 (061330, 061331) and Agència de Gestió d'Ajuts Universitaris i de Recerca-AGAUR (2005SGR00848 and 2005SGR00266). RC was funded by the Institut de Recerca Vall d'Hebron, MR and EC-L are recipients of a Juan de la Cierva and a Marató de TV3 contracts, respectively, and SAS is a recipient of a FPI scholarship of the Spanish Ministry of Education and Science. JMF-F is a Ramón y Cajal Fellow. MAV is an ICREA Academia Fellow.

Mutations in the gene encoding the pore-forming alpha(1A) subunit of P/Q Ca(2+) channels (CACNA1A) are linked to familial hemiplegic migraine. CACNA1A Y1245C is the first missense mutation described in a subject affected with childhood periodic syndromes that evolved into hemiplegic migraine. Y1245C is also the first amino acid change described in any S1 segment of CACNA1A in a hemiplegic migraine background. We found that Y1245C induced a 9-mV left shift in the current-voltage activation curve, accelerated activation kinetics, and slowed deactivation kinetics within a wide range of voltage depolarizations. Y1245C also left-shifted the voltage-dependent steady-state inactivation with a significant increase in steepness, suggesting a direct effect on the P/Q channel voltage sensor. Moreover, Y1245C reduced Gbetagamma subunits-dependent channel inhibition probably by favoring Gbetagamma dissociation from the channel; an effect also observed using action-potential-like waveforms of different durations. The formation of a new disulfide bridge between cysteines may contribute to the Y1245C effects on activation and Gbetagamma inhibition of the channel, as they were significantly reversed by the sulphydryl-reducing agent dithiothreitol. Together, our data suggest that Y1245C alters the structure of the alpha(1A) voltage sensor producing an overall gain of channel function that may explain the observed clinical phenotypes.

Objective The large conductance Ca2+ -dependent potassium channel plays a critical role in the control of vascular tone, coupling local increases in intracellular Ca2+ to membrane hyperpolarization and vascular relaxation. It also impacts blood pressure by modulating the renin-angiotensin-aldosterone system. Previous studies have shown that a polymorphism in the beta1 regulatory subunit of the Ca2+ -dependent potassium channel modulates the risk of diastolic hypertension in humans. Methods We have studied polymorphisms in the pore-forming alpha subunit gene (KCNMA1) and their association to hypertension and myocardial infarction. Results Sequencing of the KCNMA1 gene revealed two genetic variants (polymorphisms C864T and IVS17) in population-based epidemiological studies (4786 participants). We detected a significant increase in the frequency of the IVS17+37T>C polymorphism with severe systolic hypertension (48.3% for normotensive vs. 69% for severe systolic hypertension, P=0.03) and with severe general hypertension (48.7 vs. 65.8%, P=0.04), although the adjusted odd ratios did not reach statistical significance. Four C864T/IVS17 haplotypes were identified. Haplotype 4 (encompassing the C allele of the IVS17 polymorphism and the T allele of the C864T polymorphism) was related with increased severity of systolic and general hypertension as well as increased risk of myocardial infarction. Conclusion Our study provides genetic evidence that highlights the relevance of the Ca2+ -dependent potassium channel in the control of human blood pressure and its impact on cardiovascular disease.

The vertebrate transient receptor potential cationic channel TRPV4 has been proposed as an osmo- and mechanosensor channel. Studies using knock-out animal models have further emphasized the relevance of the TRPV4 channel in the maintenance of the internal osmotic equilibrium and mechanosensation. However, at the cellular level, there is still one important question to answer: does the TRPV4 channel generate the Ca(2+) signal in those cells undergoing a Ca(2+)-dependent regulatory volume decrease (RVD) response? RVD in human airway epithelia requires the generation of a Ca(2+) signal to activate Ca(2+)-dependent K(+) channels. The RVD response is lost in airway epithelia affected with cystic fibrosis (CF), a disease caused by mutations in the cystic fibrosis transmembrane conductance regulator channel. We have previously shown that the defective RVD in CF epithelia is linked to the lack of swelling-dependent activation of Ca(2+)-dependent K(+) channels. In the present study, we show the expression of TRPV4 in normal human airway epithelia, where it functions as the Ca(2+) entry pathway that triggers the RVD response after hypotonic stress, as demonstrated by TRPV4 antisense experiments. However, cell swelling failed to trigger Ca(2+) entry via TRPV4 channels in CF airway epithelia, although the channel's response to a specific synthetic activator, 4 alpha-phorbol 12,13-didecanoate, was maintained. Furthermore, RVD was recovered in CF airway epithelia treated with 4 alpha-phorbol 12,13-didecanoate. Together, these results suggest that defective RVD in CF airway epithelia might be caused by the absence of a TRPV4-mediated Ca(2+) signal and the subsequent activation of Ca(2+)-dependent K(+) channels.

Benign paroxysmal torticollis of infancy (BPTI) is a rare paroxysmal disorder characterized by recurrent episodes of head tilt and accompanying general symptoms which remit spontaneously. The rare association with gain-of-function CACNA1A mutations, similar to hemiplegic migraine, has been reported. We report here two new BPTI patients from the same family carrying a heterozygous mutation in the CACNA1A gene leading to the change p.Glu533Lys. Functional analysis revealed that this mutation induces a loss of channel function due to impaired gating by voltage and much lower current density. Our data suggest that BPTI, a periodic syndrome commonly considered a migraine precursor, con- stitutes an age-specific manifestation of defective neuronal calcium channel activity.

The transient receptor potential (TRP) superfamily of non-selective cationic channels are involved in several processes plausibly relevant to migraine pathophysiology, including multimodal sensory and pain perception, central and peripheral sensitization, and regulation of calcium homeostasis. With the aim of identifying single nucleotide polymorphisms (SNPs) in TRP genes that may confer increased genetic susceptibility to migraine, we carried out a case-control genetic association study with replication, including a total of 1,040 cases and 1,037 controls. We genotyped 149 SNPs covering 14 TRP genes with known brain expression. The two-stage study comprised samples of 555 and 485 Spanish, Caucasian patients, selected according to the ICHD-II criteria for the diagnosis of migraine without aura (MO) or migraine with aura (MA). In the discovery sample, 19 SNPs in ten TRP genes showed nominal association (P

Aims Among various hypotheses proposed for pathological tissue calcification, recent evidence supports the possibility that self-replicating calcifying nanoparticles (CNPs) can contribute to such calcification. These CNPs have been detected and isolated from calcified human tissues, including blood vessels and kidney stones, and are referred to as nanobacteria. We evaluated calcific aortic valves for the presence of CNP. Methods and results Calcific aortic valves were obtained from 75 patients undergoing surgical valve replacement. The control group was formed by eight aortic valves corresponding to patients with heart transplants. In the microbiology laboratory, valves were screened for CNP using a 4–6 weeks specific culture method. The culture for CNP was positive in 48 of the 75 valves with aortic stenosis (64.0%) in comparison with zero of eight (0%) for the control group ( P = 0.0005). The observation of cultures by way of scanning electron microscopy highlighted the resemblance in size and morphology of CNP. Conclusion Self-replicating calcific nanometer-scale particles, similar to those described as CNP from other calcific human tissues, can be cultured and visualized from calcific human aortic valves. This finding raises the question as to whether CNP contribute to the pathogenesis of the disease or whether they are only innocent bystanders.

Airway epithelial cells are exposed to changes in the osmolality of their environment under physiological and pathological conditions. The cell regulatory volume decrease (RVD) response triggered by hypotonic stress requires the coordinated activity of Cl− and K+ channels. We have investigated the molecular nature of K+ channels mediating RVD response in human tracheal and bronchial epithelial cells. Our molecular, electrophysiological and pharmacological studies demonstrate the functional expression of calciumdependent K+ channels in human airways and their contribution to the RVD response. While the main swelling-activated K+ channel in tracheal cells is an intermediate conductance potassium channel (IK, KCNN4),1 in bronchial cells, a big conductance K+ channel (BK, KCNMA1) is the key player.2 Early work in murine small intestine have established a link between the cystic fibrosis transmembrane conductance regulator (CFTR) and volume regulation, suggesting the defective RVD response observed in murine intestinal crypts of cystic fibrosis (CF) mice is caused by the dysfunction of a calcium-dependent K+ channel.3, 4 Likewise, we have found that RVD response is impaired in both human CF tracheal1 and bronchial epithelial cells. Furthermore, we have shown that this defect in volume regulation is due to the lack of swelling-induced activation of the calciumdependent potassium channel mediating RVD response.1 Our results suggest that, at least in bronchial epithelial cells, the increase in intracellular Ca2+ necessary for potassium channel activation in response to hypotonicity, is achieved by an increased Ca2+ entry trough a swelling-activated cation channel. The molecular identity of this Ca2+ entry pathway might be related to TRPV4,2 a TRP channel that has been described as responsive to changes in extracellular osmolarity.5-7 Our more recent data also suggest the altered modulation of B (big conductance) K channels in response to cell swelling might be linked to alterations in regulation of the Ca2+ entry pathway in CF bronchial cells.

The E65K polymorphism in the β 1 -subunit of the large-conductance, Ca 2+ -dependent K + (BK) channel, a key element in the control of arterial tone, has recently been associated with low prevalence of diastolic hypertension. We now report the modulatory effect of sex and age on the association of the E65K polymorphism with low prevalence of diastolic hypertension and the protective role of E65K polymorphism against cardiovascular disease. We analyzed the genotype frequency of the E65K polymorphism in 3924 participants selected randomly in two cross-sectional studies. A five-year follow-up of the cohort was performed to determine whether cardiovascular events had occurred since inclusion. Estrogen modulation of wild-type and mutant ion channel activity was assessed after heterologous expression and electrophysiological studies. Multivariate regression analyses showed that increasing age upmodulates the protective effect of the K allele against moderate-to-severe diastolic hypertension in the overall group of participants (odds ratio [OR], 0.35; P =0.006). The results remained significant when analyses were restricted to women (OR, 0.18; P =0.02) but not men (OR, 0.46; P =0.09). This effect was independent of the reported acute modulation of BK channels by estrogen. A five-year follow-up study also demonstrated a reduced age- and sex-adjusted hazard ratio of 0.11, 95% CI, 0.01 to 0.79 of K-carriers for “combined cardiovascular disease” (myocardial infarction and stroke) compared with EE homozygotes. Our study provides the first genetic evidence for the different impact of the BK channel in the control of human blood pressure in men and women, with particular relevance in aging women, and highlights the E65K polymorphism as one of the strongest genetic factors associated thus far to protection against myocardial infarction and stroke.

Hemiplegic migraine (HM) is a rare and severe subtype of autosomal dominant migraine, characterized by a complex aura including some degree of motor weakness. Mutations in three genes (CACNA1A, ATP1A2 and SCN1A) have been detected in familial and in sporadic cases. This genetically and clinically heterogeneous disorder is often accompanied by permanent ataxia, epileptic seizures, mental retardation, and chronic progressive cerebellar atrophy.