Neuroprotective or neurotoxic effects of 4-aminopyridine mediated by KChIP1 regulation through adjustment of Kv 4.3 potassium channels expression and GABA-mediated transmission in primary hippocampal cells.
4-Aminopyridine (4-AP) is a potassium channel blocker used for the treatment of neuromuscular disorders. Otherwise, it has been described to produce a large number of adverse effects among them cell death mediated mainly by blockage of K(+) channels. However, a protective effect against cell death has also been described. On the other hand, Kv channel interacting protein 1 (KChIP1) is a neuronal calcium sensor protein that is predominantly expressed at GABAergic synapses and it has been related with modulation of K(+) channels, GABAergic transmission and cell death. According to this KChIP1 could play a key role in the protective or toxic effects induced by 4-AP. We evaluated, in wild type and KChIP1 silenced primary hippocampal neurons, the effect of 4-AP (0.25μM to 2mM) with or without semicarbazide (0.3M) co-treatment after 24h and after 14 days 4-AP alone exposure on cell viability, the effect of 4-AP (0.25μM to 2mM) on KChIP1 and Kv 4.3 potassium channels gene expression and GABAergic transmission after 24h treatment or after 14 days exposure to 4-AP (0.25μM to1μM). 4-AP induced cell death after 24h (from 1mM) and after 14 days treatment. We observed that 4-AP modulates KChIP1 which regulate Kv 4.3 channels expression and GABAergic transmission. Our study suggests that KChIP1 is a key gene that has a protective effect up to certain concentration after short-term treatment with 4-AP against induced cell injury; but this protection is erased after long term exposure, due to KChIP1 down-regulation predisposing cell to 4-AP induced damages. These data might help to explain protective and toxic effects observed after overdose and long term exposure.
Department of Toxicology and Pharmacology, Veterinary School, Complutense University of Madrid, 28040 Madrid, Spain. Electronic address: jdelpino@pdi.ucm.es.
Javier
J
Del Pino
Department of Toxicology and Pharmacology, Veterinary School, Complutense University of Madrid, 28040 Madrid, Spain.
María Teresa
MT
Frejo
Department of Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, 28040 Madrid, Spain.
María José Anadon
MJA
Baselga
Department of Toxicology and Pharmacology, Veterinary School, Complutense University of Madrid, 28040 Madrid, Spain.
Miguel Andrés
MA
Capo
Department of Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, 28040 Madrid, Spain.
Paula
P
Moyano
Department of Toxicology and Legal Medicine, Medicine School, Complutense University of Madrid, 28040 Madrid, Spain.
José Manuel
JM
García
Department of Toxicology and Pharmacology, Veterinary School, Complutense University of Madrid, 28040 Madrid, Spain.
María Jesús
MJ
Díaz
D015761:4-Aminopyridine / Q000494:pharmacology* / Q000633:toxicity; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019610:Cytoprotection; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism; D051605:Kv Channel-Interacting Proteins / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology* / Q000633:toxicity; D026902:Potassium Channel Blockers / Q000494:pharmacology* / Q000633:toxicity; D061251:Primary Cell Culture; D034622:RNA Interference; D017208:Rats, Wistar; D012663:Semicarbazides / Q000494:pharmacology; D051672:Shal Potassium Channels / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects*; D013997:Time Factors; D014162:Transfection; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
C497023:Kcnd3 protein, rat; C496757:Kcnip1 protein, rat; D051605:Kv Channel-Interacting Proteins; D018696:Neuroprotective Agents; D026902:Potassium Channel Blockers; D012663:Semicarbazides; D051672:Shal Potassium Channels; C010059:carbamylhydrazine; D005680:gamma-Aminobutyric Acid; D015761:4-Aminopyridine; C505410:Casp3 protein, rat; D053148:Caspase 3; D053179:Caspase 7
4-Aminopyridine; Cell death; GABA; KChIP1; Kv 4.3; Rats