AUTHOR=Liu Shenhai , Jin Zhe , Zhang Yiling , Rong ShiKuo , He Wenxin , Sun Kuisheng , Wan Din , Huo Junming , Xiao Lifei , Li Xinxiao , Ding Na , Wang Feng , Sun Tao 

TITLE=The Glucagon-Like Peptide-1 Analogue Liraglutide Reduces Seizures Susceptibility, Cognition Dysfunction and Neuronal Apoptosis in a Mouse Model of Dravet Syndrome

JOURNAL=Frontiers in Pharmacology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2020.00136

DOI=10.3389/fphar.2020.00136

ISSN=1663-9812

ABSTRACT=<p>Dravet syndrome (DS) is a refractory epilepsy typically caused by heterozygous mutations of the <italic>Scn1a</italic> gene, which encodes the voltage-gated sodium channel Nav1.1. Glucagon-like peptide-1 (GLP-1) analogues, effective therapeutic agents for the treatment of diabetes, have recently become attractive treatment modalities for patients with nervous system disease; however, the impact of GLP-1 analogues on DS remains unknown. This study aimed to determine the neuroprotective role of liraglutide in mouse and cell models of <italic>Scn1a</italic> KO-induced epilepsy. Epileptic susceptibility, behavioral changes, and behavioral seizures were assessed using electroencephalography (EEG), IntelliCage (TSE Systems, Bad Homburg, Germany), and the open field task. Morphological changes in brain tissues were observed using hematoxylin and eosin (HE) and Nissl staining. Expression of apoptosis-related proteins and the mammalian target of rapamycin (mTOR) signaling pathway were determined using immunofluorescence and western blotting in <italic>Scn1a</italic> KO-induced epileptic mice <italic>in vitro</italic>. <italic>Scn1a</italic> KO model cell proliferation was evaluated using the Cell Counting Kit-8 assay, and the effect of liraglutide on cellular apoptosis levels was examined using Annexin V-FITC/PI flow cytometry. Apoptotic signal proteins and mTOR were assessed using reverse transcription - quantitative polymerase chain reaction (RT-qPCR) and western blotting. Our results showed that liraglutide significantly increased mRNA ((0.31 ± 0.04) *10<sup>-3</sup> vs. (1.07 ± 0.08) * 10<sup>-3</sup>, <italic>P</italic> = 0.0004) and protein (0.10 ± 0.02 <italic>vs.</italic> 0.27 ± 0.02, <italic>P</italic> = 0.0006) expression of <italic>Scn1a</italic> in <italic>Scn1a</italic> KO-induced epileptic mice. In addition, liraglutide significantly alleviated electroencephalographic seizures, the severity of responses to epileptic seizures (96.53 ± 0.45 % vs. 85.98 ± 1.24 %, <italic>P</italic> = 0.0003), cognitive dysfunction, and epileptic-related necrotic neurons (9.76 ± 0.91 % vs. 19.65 ± 2.64 %, <italic>P</italic> = 0.0005) in <italic>Scn1a</italic> KO-induced epileptic mice. Moreover, liraglutide protected against <italic>Scn1a</italic> KO-induced apoptosis, which was manifested in the phosphorylation of mTOR (KO+NS: 1.99 ± 0.31 vs. KO+Lira: 0.97 ± 0.18, <italic>P</italic> = 0.0004), as well as the downregulation of cleaved caspase-3 (KO+NS: 0.49 ± 0.04 vs. KO+Lira: 0.30 ± 0.01, <italic>P</italic> = 0.0003) and restoration of the imbalance between BAX (KO+NS: 0.90 ± 0.02 vs. KO+Lira: 0.75 ± 0.04, <italic>P</italic> = 0.0005) and BCL-2 (KO+NS: 0.46 ± 0.02 vs. KO+Lira: 0.61 ± 0.02, <italic>P</italic> = 0.0006). Collectively, these results show that liraglutide reduces seizure susceptibility and cognitive dysfunction in the mouse model of Dravet syndrome, and exerts anti-apoptotic and neuroprotective effects in <italic>Scn1a</italic> KO mice and cells.</p>