Epilepsy is a debilitating disease affecting 1-2% of the world's population. Despite this high prevalence, 30% of patients suffering from epilepsy are not successfully managed by current medication suggesting a critical need for new anti-epileptic drugs (AEDs). In an effort to discover new therapeutics for the management of epilepsy, we began our study by screening drugs that, like some currently used AEDs, inhibit histone deacetylases (HDACs) using a well-established larval zebrafish model. In this model, 7-day post fertilization (dpf) larvae are treated with the widely used seizure-inducing compound pentylenetetrazol (PTZ) which stimulates a rapid increase in swimming behavior previously determined to be a measurable manifestation of seizures. In our first screen, we tested a number of different HDAC inhibitors and found that one, 2-benzamido-1 4-naphthoquinone (NQN1), significantly decreased swim activity to levels equal to that of valproic acid, 2-n-propylpentanoic acid (VPA). We continued to screen structurally related compounds including Vitamin K3 (VK3) and a number of novel Vitamin K (VK) analogs. We found that VK3 was a robust inhibitor of the PTZ-induced swim activity, as were several of our novel compounds. Three of these compounds were subsequently tested on mouse seizure models at the National Institute of Neurological Disorders and Stroke (NINDS) Anticonvulsant Screening Program. Compound 2h reduced seizures particularly well in the minimal clonic seizure (6Hz) and corneal-kindled mouse models of epilepsy, with no observable toxicity. As VK3 affects mitochondrial function, we tested the effects of our compounds on mitochondrial respiration and ATP production in a mouse hippocampal cell line. We demonstrate that these compounds affect ATP metabolism and increase total cellular ATP. Our data indicate the potential utility of these and other VK analogs for the prevention of seizures and suggest the potential mechanism for this protection may lie in the ability of these compounds to affect energy production.
Keywords: 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid; 2-benzamido-1,4-naphthoquinone; 2-propylpentane hydroxamic acid; 2h; 2j; 2q; 3n; AED; ATP; ATP metabolism; DMEM; DMSO; Dulbecco’s Modified Eagle’s Medium; ECAR; ETC; FCCP; HDAC; HEPES; MB; NINDS; NQN1; National Institute of Neurological Disorders and Stroke; OCR; PTZ; ROS; SAHA; SEM; SOD2; VK; VK analog modified by the addition of a benzyl amine group to the 2′ position of the 1,4-naphthoquinone motif of VK; VK analog. It is a modification of analog 2j with the addition of chlorine at the meta position of the added benzene ring; VK analog. It is a modification of analog 2j, with the addition of a terminal alkyne to the added benzene; VK analog. It was created by replacing the central methylene group of analog 2j with a carbonyl group; VK3; VPA; VPHA; Vitamin K; Vitamin K3; adenosine triphosphate; anti-epileptic drug; days post fertilization; dimethyl sulfoxide; dpf; electron transport chain; epilepsy; extracellular acidification rate; histone deacetylase; methylene blue; mitochondria; oxygen consumption rate; pentylenetetrazol; reactive oxygen species; respiration; standard error of the mean; suberoylanilide hydroxamic acid; superoxide dismutase; trifluorocarbonylcyanide phenylhydrazone; valproic acid, 2-n-propylpentanoic acid; zebrafish.
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