plic-1 Rescue Mechanisms of Mutant GABAA Subunit Mediated Developmental and Epileptic Encephalopathies
Abstract number :
3.046
Submission category :
1. Basic Mechanisms / 1D. Mechanisms of Therapeutic Interventions
Year :
2022
Submission ID :
2204363
Source :
www.aesnet.org
Presentation date :
12/5/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:24 AM
Authors :
Gerald Nwosu, BS. – Meharry Medical College; Wangzhen Shen, Ph.D. – Vanderbilt University Medical Center; Jingqiong Kang, M.D. Ph.D. – Vanderbilt University Medical Center
Rationale: The β3 subunit of the GABAA receptor is abundantly expressed during the development of the central nervous system and its mutation has been linked to Lennox-Gastaut syndrome (LGS) in humans. The impact of the mutation in the brain and how it can cause a developmental and epileptic phenotype are poorly understood, let alone mechanism-based treatment. Ubiquilin-1(Plic-1) is an adaptor protein between ubiquitin and the proteasome that has been reported to stabilize the β3 subunit. Preliminary work in the lab has shown that overexpression of Plic-1 can rescue mutant subunit containing receptors.
Methods: We have developed a novel mouse model of LGS (Gabrb3+/N328D) to characterize the major defects caused by the mutation from molecular to neurobehavioral levels. We will determine if overexpression of Plic-1 can rescue the molecular and functional phenotypes of the mutant mice. Expression of the α2, β3, and γ2 subunits of the GABAA receptor in both total lysates, cell surface level, and synaptosomes will be investigated via immunoblot in mice with or without overexpression of Plic-1. Video monitoring and synchronized EEG recordings will be conducted to evaluate the effect of overexpression of Plic-1 on seizure activity.
Results: The expression of β3 subunits was reduced in both total lysates and synaptosomes in the Gabrb3+/N328D. Plic-1 rescued the expression and function of mutant β3 subunit containing receptors in vitro and in Gabrb3+/N328D mice. Plic-1 has also shown to reduce the onset of seizures in co-expressing mice.
Conclusions: Plic-1 overexpression is proving to be a relevant therapeutic option for the alleviation of epileptic symptoms attributed to mutations of GABAA receptor subunits. Further research will be carried out to study the off target effects and efficacy for rescuing mutations of other subunits.
Funding: This project was supported, in part, by grants from Vanderbilt Clinical and Translation Science Award, Vanderbilt Brain Institute pilot grant and Vanderbilt Discovery grant, NINDS R01 NS082635, NS121718 to J.Q.K., and NIH RISE Grant #: 5 R25 GM 59994-19.
Basic Mechanisms