Direct Activation of KCC2 with Cmp2 Arrests Refractory Status Epilepticus and Limits the Subsequent Neuronal Injury
Abstract number :
3.278
Submission category :
7. Anti-seizure Medications / 7A. Animal Studies
Year :
2022
Submission ID :
2204628
Source :
www.aesnet.org
Presentation date :
12/5/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:25 AM
Authors :
Shu Fun Josephine Ng, PhD – Tufts University School of Medicine; Rebecca Jarvis, PhD – AstraZeneca; Anna Nathanson, PhD – Neuroscience – Tufts University School of Medicine; Ross Cardarelli, PhD – Neuroscience – Tufts University School of Medicine; Krithika Abiraman, PhD – Neuroscience – Tufts University School of Medicine; Tarek Deeb, PhD – Neuroscience – Tufts University School of Medicine; Joshua Smalley, PhD – Neuroscience – Tufts University School of Medicine; Aarti Kawatkar, PhD – AstraZeneca; Leslie Conway, PhD – Neuroscience – Tufts University School of Medicine; Nicholas Brandon, PhD – AstraZeneca; Fergus Wade, BS – Neuroscience – Tufts University School of Medicine; Aidan Evans-Strong, BS – Neuroscience – Tufts University School of Medicine; Ian Gurrell, PhD – AstraZeneca; Iain Chessell, PhD – AstraZeneca; Aaron Goldman, PhD – Ovid Therapeutics; Jamie Maguire, PhD – Neuroscience – Tufts University School of Medicine; Stephen Moss, PhD – Neuroscience – Tufts University School of Medicine; University College London
Rationale: Fast synaptic inhibition in the adult brain is mediated by γ-aminobutyric acid type A receptors (GABAARs), that mediate Cl- dependent neuronal hyperpolarization. Hyperpolarizing GABAAR currents are critically dependent upon efficient Cl- extrusion, a process that is facilitated by the neuronal specific K+/Cl- co-transporter KCC2, the activity of which contributes to the anticonvulsant efficacy of benzodiazepines (BDZ), barbiturates and neurosteroids, all of which allosterically potentiate GABAAR activity. In accordance with its role in supporting inhibitory neurotransmission, mutations in KCC2 result in epilepsy and deficits in its activity are implicated in drug resistant seizures and the subsequent neuronal death.
Methods: Using high-throughput screening of 1.3 million chemically distinct chemical entities we have identified a family of small molecules that directly bind to and activate KCC2. Subsequent optimization for potency and brain exposure resulted in identification of Cmp2. Its effects on the severity of chemico-convulsant-induced Status Epilepticus (SE), the development of BDZ-resistant seizures and the subsequent neuronal injury were examined in mice.
Results: Cmp2 binds with high affinity to KCC2 and increases its activity, without modifying its stability on the plasma membrane or the phosphorylation of key regulatory residues. KCC2 activation reduces neuronal Cl- accumulation and limits the development of hyperexcitability. Cmp2 rapidly accumulates in the rodent brain and does not induce any overt effects on behavior, but selectively elevates EEG gamma power. This compound slowed the development of SE induced by kainate (KA) and prevented the subsequent development of BDZ resistance. Moreover, Cmp2 restored the efficacy of BDZs to terminate ongoing SE and abolished KA-induced neuronal cell death 48-72 hours following this trauma.
Conclusions: Our results provide evidence that agents like Cmp2 that directly increase KCC2 activity are efficacious in alleviating BDZ-resistant seizures and in limiting the subsequent neuronal injury.
Funding: This work was funded by; National Institutes of Health (NIH)–National Institute of Neurological Disorders and Stroke Grants NS087662, NS081986, NS108378, NS101888, NS103865, NS 111338, NIH–National Institute of Mental Health Grant MH118263. KA, JN, LC, and RC were fellows of, and funded by the AstraZeneca Postdoctoral Program. KA, and JN, are currently supported by Ovid Therapeutics.
Anti-seizure Medications