Familial hemiplegic migraine type 1 (FHM1) is a rare monogenic subtype of migraine with aura caused by mutations in CACNA1A that encodes the alpha(1A) subunit of voltage-gated Ca(V)2.1 calcium... Show moreFamilial hemiplegic migraine type 1 (FHM1) is a rare monogenic subtype of migraine with aura caused by mutations in CACNA1A that encodes the alpha(1A) subunit of voltage-gated Ca(V)2.1 calcium channels. Transgenic knock-in mice that carry the human FHM1 R192Q missense mutation ('FHM1 R192Q mice') exhibit an increased susceptibility to cortical spreading depression (CSD), the mechanism underlying migraine aura. Here, we analysed gene expression profiles from isolated cortical tissue of FHM1 R192Q mice 24 h after experimentally induced CSD in order to identify molecular pathways affected by CSD. Gene expression profiles were generated using deep serial analysis of gene expression sequencing. Our data reveal a signature of inflammatory signalling upon CSD in the cortex of both mutant and wild-type mice. However, only in the brains of FHM1 R192Q mice specific genes are up-regulated in response to CSD that are implicated in interferon-related inflammatory signalling. Our findings show that CSD modulates inflammatory processes in both wild-type and mutant brains, but that an additional unique inflammatory signature becomes expressed after CSD in a relevant mouse model of migraine. Show less
Kaja S, Van de Ven RCG, Broos LAM, Frants RR, Ferrari MD, Van den Maagdenberg AMJM, Plomp JJ. Severe and progressive neurotransmitter release aberrations in familial hemiplegic migraine type 1... Show moreKaja S, Van de Ven RCG, Broos LAM, Frants RR, Ferrari MD, Van den Maagdenberg AMJM, Plomp JJ. Severe and progressive neurotransmitter release aberrations in familial hemiplegic migraine type 1 Cacna1a S218L knock-in mice. J Neurophysiol 104: 1445-1455, 2010. First published July 14, 2010; doi:10.1152/jn.00012.2010. Familial hemiplegic migraine type 1 (FHM1) is caused by mutations in the CACNA1A gene, encoding neuronal presynaptic Ca(V)2.1 (P/Q-type) Ca2+ channels. These channels mediate neurotransmitter release at many central synapses and at the neuromuscular junction (NMJ). Mutation S218L causes a severe neurological phenotype of FHM and, additionally, ataxia and susceptibility to seizures, delayed brain edema, and fatal coma after minor head trauma. Recently, we generated a Cacna1a S218L knock-in mutant mouse, displaying these features and reduced survival. A first electrophysiological study showed high susceptibility for cortical spreading depression, enhanced neuronal soma Ca2+ influx, and at diaphragm NMJs, a considerable increase of neurotransmitter release. We here assessed the function of S218L knock-in NMJs at several muscle types in great detail. Pharmacological analyses using specific Ca-V subtype-blocking toxins excluded compensatory contribution of non-Ca(V)2.1 channels. Endplate potentials were considerably broadened at many NMJs. High rate (40 Hz)-evoked acetylcholine release was slightly reduced; however, it was not associated with block of neurotransmission causing weakness, as assessed with grip strength measurements and in vitro muscle contraction experiments. The synaptopathy clearly progressed with age, including development of an increased acetylcholine release at low-rate nerve stimulation at physiological extracellular Ca2+ concentration and further endplate potential broadening. Our results suggest enhanced Ca2+ influx into motor nerve terminals through S218L-mutated presynaptic Ca(V)2.1 channels, likely because of the earlier reported negative shift of activation potential and reduced inactivation. Similar severe aberrations at central synapses of S218L mutant mice and humans may underlie or contribute to the drastic neurological phenotype. Show less
Klychnikov, O.I.; Li, K.W.; Sidorov, I.A.; Loos, M.; Spijker, S.; Broos, L.A.M.; ... ; Maagdenberg, A.M.J.M. van den 2010
Familial hemiplegic migraine type 1 (FHM1) is caused by missense mutations in the CACNA1A gene that encodes the alpha 1A pore-forming subunit of Ca(v)2.1 Ca2+ channels. Knock-in transgenic mice... Show moreFamilial hemiplegic migraine type 1 (FHM1) is caused by missense mutations in the CACNA1A gene that encodes the alpha 1A pore-forming subunit of Ca(v)2.1 Ca2+ channels. Knock-in transgenic mice expressing Ca(v)2.1 Ca2+ channels with a human pathogenic FHM1 mutation reveal enhanced glutamatergic neurotransmission in the cortex. In this study, we employed an ITRAQ-based LC-LC MS/MS approach to identify differentially expressed proteins in cortical synapse proteomes of Cacna1a R192Q KI and wild-type mice. All expression differences determined were subtle and in the range of 10-30%. Observed upregulated proteins in the mutant mice are Involved in processes, such as neurite outgrowth and actin dynamics, vesicle turnover, and glutamate transporters. Our data support the view that in Cacna1a R192Q KI mice, several compensatory mechanisms counterbalancing a dysregulated glutamatergic signaling have come Into effect. We propose that such adaptation mechanisms at the synapse level may play a role in the pathophysiology of FHM and possibly in the common forms of migraine. Show less
Maagdenberg, A.M.J.M. van den; Pizzorusso, T.; Kaja, S.; Terpolilli, N.; Shapovalova, M.; Hoebeek, F.E.; ... ; Ferrari, M.D. 2010
Objective: The CACNA1A gene encodes the pore-forming subunit of neuronal Ca(V)2.1 Ca2+ channels. In patients, the S218L CACNA1A mutation causes a dramatic hemiplegic migraine syndrome that is... Show moreObjective: The CACNA1A gene encodes the pore-forming subunit of neuronal Ca(V)2.1 Ca2+ channels. In patients, the S218L CACNA1A mutation causes a dramatic hemiplegic migraine syndrome that is associated with ataxia, seizures, and severe, sometimes fatal, brain edema often triggered by only a mild head trauma. Methods: We introduced the S218L mutation into the mouse Cacna1a gene and studied the mechanisms for the S218L syndrome by analyzing the phenotypic, molecular, and electrophysiological consequences. Results: Cacna1a(S218L) mice faithfully mimic the associated clinical features of the human S218L syndrome. S218L neurons exhibit a gene dosage-dependent negative shift in voltage dependence of Ca(V)2.1 channel activation, resulting in enhanced neurotransmitter release at the neuromuscular junction. Cacna1a(S218L) mice also display an exquisite sensitivity to cortical spreading depression (CSD), with a vastly reduced triggering threshold, an increased propagation velocity, and frequently multiple CSD events after a single stimulus. In contrast, mice bearing the R192Q CACNA1A mutation, which in humans causes a milder form of hemiplegic migraine, typically exhibit only a single CSD event after one triggering stimulus. Interpretation: The particularly low CSD threshold and the strong tendency to respond with multiple CSD events make the S218L cortex highly vulnerable to weak stimuli and may provide a mechanistic basis for the dramatic phenotype seen in S218L mice and patients. Thus, the S218L mouse model may prove a valuable tool to further elucidate mechanisms underlying migraine, seizures, ataxia, and trauma-triggered cerebral edema. ANN NEUROL 2010;67:85-98 Show less
