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Selma A Serra,
Ester Cuenca-León,
Artur Llobet,
Francisca Rubio-Moscardo,
Cristina Plata,
Oriel Carreño,
Noèlia Fernàndez-Castillo,
Roser Corominas,
Miguel A Valverde,
Alfons Macaya,
Bru Cormand,
José M Fernández-Fernández
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ABSTRACT: Familial hemiplegic migraine (FHM)-causing mutations in the gene encoding the P/Q Ca(2+) channel alpha(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 (alpha(1A(A454T))) that does not cause FHM but is associated with the absence of sensorimotor symptoms in a migraine with aura pedigree. Alpha(1A(A454T)) channels showed weakened regulation of voltage-dependent steady-state inactivation by Ca(V)beta subunits. More interestingly, 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.
Proceedings of the National Academy of Sciences 01/2010; 107(4):1672-7. · 9.68 Impact Factor
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ABSTRACT: 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.
Neuroscience Letters 06/2009; 455(2):105-9. · 2.11 Impact Factor
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Ester Cuenca-León,
Isabel Banchs, Selma A Serra,
Pilar Latorre,
Noèlia Fernàndez-Castillo,
Roser Corominas,
Miguel A Valverde,
Víctor Volpini,
José M Fernández-Fernández,
Alfons Macaya,
Bru Cormand
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ABSTRACT: 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 Ca(2+) 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 Ca(2+) 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.
Journal of the neurological sciences 03/2009; 280(1-2):10-4. · 2.32 Impact Factor
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ABSTRACT: Mechanical and osmotic sensitivity of the transient receptor potential vanilloid 4 (TRPV4) channel depends on phospholipase A2 (PLA2) activation and the subsequent production of the arachidonic acid metabolites, epoxyeicosatrienoic acid (EET). We show that both high viscous loading and hypotonicity stimuli in native ciliated epithelial cells use PLA2-EET as the primary pathway to activate TRPV4. Under conditions of low PLA2 activation, both also use extracellular ATP-mediated activation of phospholipase C (PLC)-inositol trisphosphate (IP3) signaling to support TRPV4 gating. IP3, without being an agonist itself, sensitizes TRPV4 to EET in epithelial ciliated cells and cells heterologously expressing TRPV4, an effect inhibited by the IP3 receptor antagonist xestospongin C. Coimmunoprecipitation assays indicated a physical interaction between TRPV4 and IP3 receptor 3. Collectively, our study suggests a functional coupling between plasma membrane TRPV4 channels and intracellular store Ca2+ channels required to initiate and maintain the oscillatory Ca2+ signal triggered by high viscosity and hypotonic stimuli that do not reach a threshold level of PLA2 activation.
The Journal of General Physiology 06/2008; 131(5):i2. · 3.84 Impact Factor
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ABSTRACT: Mechanical and osmotic sensitivity of the transient receptor potential vanilloid 4 (TRPV4) channel depends on phospholipase
A2 (PLA2) activation and the subsequent production of the arachidonic acid metabolites, epoxyeicosatrienoic acid (EET). We show that
both high viscous loading and hypotonicity stimuli in native ciliated epithelial cells use PLA2–EET as the primary pathway to activate TRPV4. Under conditions of low PLA2 activation, both also use extracellular ATP-mediated activation of phospholipase C (PLC)–inositol trisphosphate (IP3) signaling to support TRPV4 gating. IP3, without being an agonist itself, sensitizes TRPV4 to EET in epithelial ciliated cells and cells heterologously expressing
TRPV4, an effect inhibited by the IP3 receptor antagonist xestospongin C. Coimmunoprecipitation assays indicated a physical interaction between TRPV4 and IP3 receptor 3. Collectively, our study suggests a functional coupling between plasma membrane TRPV4 channels and intracellular
store Ca2+ channels required to initiate and maintain the oscillatory Ca2+ signal triggered by high viscosity and hypotonic stimuli that do not reach a threshold level of PLA2 activation.
The Journal of Cell Biology 04/2008; 181(1):143-155. · 10.26 Impact Factor
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ABSTRACT: Oxidative stress (OS) underlies neuronal dysfunction in many neurodegenerative disorders. Regulator of Calcineurin 1 (RCAN1 or DSCR1) is a dose-sensitive gene whose overexpression has been linked to Down syndrome (DS) and Alzheimer's disease (AD) neuropathology and to the response of cells to stress stimuli. Here, we show that RCAN1 mRNA and protein expression are sensitive to OS in primary neurons, and we evaluate the involvement of RCAN1 dosage in neuronal death induced by OS. We find that Rcan1(-/-) neurons display an increased resistance to damage by H(2)O(2), which can be reverted by RCAN1 overexpression or by exogenous inhibitors of calcineurin. Although increased intracellular Ca(2+) concentration is an important factor in OS-mediated cell death, our results show that Ca(2+) loading after exposure to H(2)O(2) was similar in Rcan1(+/+) and Rcan1(-/-) neurons. Our data further suggest that CaN and NFAT signaling protect against OS in both Rcan1(+/+) and Rcan1(-/-) neurons. To explain the observed differential vulnerability, we therefore propose a mechanism downstream of H(2)O(2)-mediated Ca(2+) entry, involving calcineurin-NFAT signaling. These findings highlight the importance of RCAN1 gene dosage in the modulation of cell survival and death pathways and suggest that changes in the amount of RCAN1 could represent an important mechanism for regulating susceptibility to neurodegeneration, especially in DS and AD.
Human Molecular Genetics 06/2007; 16(9):1039-50. · 7.64 Impact Factor
