Sabrin Haddad, Cornelia Ablinger, Ruslan Stanika, Manuel Hessenberger, Marta Campiglio, Nadine J Ortner, Petronel Tuluc, Gerald J Obermair
{"title":"与发育和癫痫性脑病相关的 CACNA2D2 双重突变会影响α2δ-2 的钙通道依赖性和突触功能。","authors":"Sabrin Haddad, Cornelia Ablinger, Ruslan Stanika, Manuel Hessenberger, Marta Campiglio, Nadine J Ortner, Petronel Tuluc, Gerald J Obermair","doi":"10.1111/jnc.16197","DOIUrl":null,"url":null,"abstract":"<p><p>α<sub>2</sub>δ proteins serve as auxiliary subunits of voltage-gated calcium channels and regulate channel membrane expression and current properties. Besides their channel function, α<sub>2</sub>δ proteins regulate synapse formation, differentiation, and synaptic wiring. Considering these important functions, it is not surprising that CACNA2D1-4, the genes encoding for α<sub>2</sub>δ-1 to -4 isoforms, have been implicated in neurological, neurodevelopmental, and neuropsychiatric disorders. Mutations in CACNA2D2 have been associated with developmental and epileptic encephalopathy (DEE) and cerebellar atrophy. In our present study, we performed a detailed functional characterization of the p.R593P mutation in α<sub>2</sub>δ-2, a homozygous mutation previously identified in two siblings with DEE. Importantly, we analyzed both calcium channel-dependent as well as synaptic functions of α<sub>2</sub>δ-2. Our data show that the corresponding p.R596P mutation in mouse α<sub>2</sub>δ-2 drastically decreases membrane expression and synaptic targeting of α<sub>2</sub>δ-2. This defect correlates with altered biophysical properties of postsynaptic Ca<sub>V</sub>1.3 channel but has no effect on presynaptic Ca<sub>V</sub>2.1 channels upon heterologous expression in tsA201 cells. However, homologous expression of α<sub>2</sub>δ-2_R596P in primary cultures of hippocampal neurons affects the ability of α<sub>2</sub>δ-2 to induce a statistically significant increase in the presynaptic abundance of endogenous Ca<sub>V</sub>2.1 channels and presynaptic calcium transients. Moreover, our data demonstrate that in addition to lowering membrane expression, the p.R596P mutation reduces the trans-synaptic recruitment of GABA<sub>A</sub> receptors and presynaptic synapsin clustering in glutamatergic synapses. Lastly, the α<sub>2</sub>δ-2_R596P reduces the amplitudes of glutamatergic miniature postsynaptic currents in transduced hippocampal neurons. Taken together, our data strongly link the human biallelic p.R593P mutation to the underlying severe neurodevelopmental disorder and highlight the importance of studying α<sub>2</sub>δ mutations not only in the context of channelopathies but also synaptopathies.</p>","PeriodicalId":16527,"journal":{"name":"Journal of Neurochemistry","volume":" ","pages":""},"PeriodicalIF":4.2000,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"A biallelic mutation in CACNA2D2 associated with developmental and epileptic encephalopathy affects calcium channel-dependent as well as synaptic functions of α<sub>2</sub>δ-2.\",\"authors\":\"Sabrin Haddad, Cornelia Ablinger, Ruslan Stanika, Manuel Hessenberger, Marta Campiglio, Nadine J Ortner, Petronel Tuluc, Gerald J Obermair\",\"doi\":\"10.1111/jnc.16197\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>α<sub>2</sub>δ proteins serve as auxiliary subunits of voltage-gated calcium channels and regulate channel membrane expression and current properties. Besides their channel function, α<sub>2</sub>δ proteins regulate synapse formation, differentiation, and synaptic wiring. Considering these important functions, it is not surprising that CACNA2D1-4, the genes encoding for α<sub>2</sub>δ-1 to -4 isoforms, have been implicated in neurological, neurodevelopmental, and neuropsychiatric disorders. Mutations in CACNA2D2 have been associated with developmental and epileptic encephalopathy (DEE) and cerebellar atrophy. In our present study, we performed a detailed functional characterization of the p.R593P mutation in α<sub>2</sub>δ-2, a homozygous mutation previously identified in two siblings with DEE. Importantly, we analyzed both calcium channel-dependent as well as synaptic functions of α<sub>2</sub>δ-2. Our data show that the corresponding p.R596P mutation in mouse α<sub>2</sub>δ-2 drastically decreases membrane expression and synaptic targeting of α<sub>2</sub>δ-2. This defect correlates with altered biophysical properties of postsynaptic Ca<sub>V</sub>1.3 channel but has no effect on presynaptic Ca<sub>V</sub>2.1 channels upon heterologous expression in tsA201 cells. However, homologous expression of α<sub>2</sub>δ-2_R596P in primary cultures of hippocampal neurons affects the ability of α<sub>2</sub>δ-2 to induce a statistically significant increase in the presynaptic abundance of endogenous Ca<sub>V</sub>2.1 channels and presynaptic calcium transients. Moreover, our data demonstrate that in addition to lowering membrane expression, the p.R596P mutation reduces the trans-synaptic recruitment of GABA<sub>A</sub> receptors and presynaptic synapsin clustering in glutamatergic synapses. Lastly, the α<sub>2</sub>δ-2_R596P reduces the amplitudes of glutamatergic miniature postsynaptic currents in transduced hippocampal neurons. Taken together, our data strongly link the human biallelic p.R593P mutation to the underlying severe neurodevelopmental disorder and highlight the importance of studying α<sub>2</sub>δ mutations not only in the context of channelopathies but also synaptopathies.</p>\",\"PeriodicalId\":16527,\"journal\":{\"name\":\"Journal of Neurochemistry\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":4.2000,\"publicationDate\":\"2024-08-19\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Neurochemistry\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.1111/jnc.16197\",\"RegionNum\":3,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"BIOCHEMISTRY & MOLECULAR BIOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Neurochemistry","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1111/jnc.16197","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
A biallelic mutation in CACNA2D2 associated with developmental and epileptic encephalopathy affects calcium channel-dependent as well as synaptic functions of α2δ-2.
α2δ proteins serve as auxiliary subunits of voltage-gated calcium channels and regulate channel membrane expression and current properties. Besides their channel function, α2δ proteins regulate synapse formation, differentiation, and synaptic wiring. Considering these important functions, it is not surprising that CACNA2D1-4, the genes encoding for α2δ-1 to -4 isoforms, have been implicated in neurological, neurodevelopmental, and neuropsychiatric disorders. Mutations in CACNA2D2 have been associated with developmental and epileptic encephalopathy (DEE) and cerebellar atrophy. In our present study, we performed a detailed functional characterization of the p.R593P mutation in α2δ-2, a homozygous mutation previously identified in two siblings with DEE. Importantly, we analyzed both calcium channel-dependent as well as synaptic functions of α2δ-2. Our data show that the corresponding p.R596P mutation in mouse α2δ-2 drastically decreases membrane expression and synaptic targeting of α2δ-2. This defect correlates with altered biophysical properties of postsynaptic CaV1.3 channel but has no effect on presynaptic CaV2.1 channels upon heterologous expression in tsA201 cells. However, homologous expression of α2δ-2_R596P in primary cultures of hippocampal neurons affects the ability of α2δ-2 to induce a statistically significant increase in the presynaptic abundance of endogenous CaV2.1 channels and presynaptic calcium transients. Moreover, our data demonstrate that in addition to lowering membrane expression, the p.R596P mutation reduces the trans-synaptic recruitment of GABAA receptors and presynaptic synapsin clustering in glutamatergic synapses. Lastly, the α2δ-2_R596P reduces the amplitudes of glutamatergic miniature postsynaptic currents in transduced hippocampal neurons. Taken together, our data strongly link the human biallelic p.R593P mutation to the underlying severe neurodevelopmental disorder and highlight the importance of studying α2δ mutations not only in the context of channelopathies but also synaptopathies.
期刊介绍:
Journal of Neurochemistry focuses on molecular, cellular and biochemical aspects of the nervous system, the pathogenesis of neurological disorders and the development of disease specific biomarkers. It is devoted to the prompt publication of original findings of the highest scientific priority and value that provide novel mechanistic insights, represent a clear advance over previous studies and have the potential to generate exciting future research.