Upregulation of liprin-α1 protein in the temporal neocortex of intractable epileptic patients and experimental rats

Exploring the pathogenesis of canine epilepsy using a systems genetics method and implications for anti-epilepsy drug discovery

Epilepsy is a common neurological disorder in domestic dogs. However, its complex mechanism involves multiple genetic and environmental factors that make it challenging to identify the real pathogenic factors contributing to epilepsy, particularly for idiopathic epilepsy. Conventional genome-wide association studies (GWASs) can detect various genes associated with epilepsy, although they primarily detect the effects of single-site mutations in epilepsy while ignoring their interactions. In this study, we used a systems genetics method combining both GWAS and gene interactions and obtained 26 significantly mutated subnetworks. Among these subnetworks, seven genes were reported to be involved in neurological disorders. Combined with gene ontology enrichment analysis, we focused on 4 subnetworks that included traditional GWAS-neglected genes. Moreover, we performed a drug enrichment analysis for each subnetwork and identified significantly enriched candidate anti-epilepsy drugs using a hypergeometric test. We discovered 22 potential drug combinations that induced possible synergistic effects for epilepsy treatment, and one of these drug combinations has been confirmed in the Drug Combination database (DCDB) to have beneficial anti-epileptic effects. The method proposed in this study provides deep insight into the pathogenesis of canine epilepsy and implications for anti-epilepsy drug discovery.

The microRNA miR-124 suppresses seizure activity and regulates CREB1 activity

miR-124, a brain-specific microRNA, was originally considered as a key regulator in neuronal differentiation and the development of the nervous system. Here we showed that miR-124 expression was suppressed in patients with epilepsy and rats after drug induced-seizures. Intrahippocampal administration of a miR-124 duplex led to alleviated seizure severity and prolonged onset latency in two rat models (pentylenetetrazole- and pilocarpine-induced seizures), while miR-124 inhibitor led to shortened onset latency in pilocarpine-induced seizure rat models. Moreover, the result of local field potentials (LFPs) records further demonstrated miR-124 may have anti-epilepsy function. Inhibition of neuronal firing by miR-124 was associated with the suppression of mEPSC, AMPAR- and NMDAR-mediated currents, which were accompanied by decreased surface expression of NMDAR. In addition, miR-124 injection resulted in decreased activity and expression of cAMP-response element-binding protein1 (CREB1). a key regulator in epileptogenesis. A dual-luciferase reporter assay was used to confirm that miR-124 targeted directly the 3'UTR of CREB1 gene and repressed the CREB1 expression in HEK293T cells. Immunoprecipitation studies confirmed that the CREB1 antibody effectively precipitated CREB1 and NMDAR1 but not GLUR1 from rat brain hippocampus. These results revealed a previously unknown function of miR-124 in neuronal excitability and provided a new insight into molecular mechanisms underlying epilepsy.

Increased expression of copine VI in patients with refractory epilepsy and a rat model

Copine VI (CPNE6) is a member of copines family, a calcium-dependent phospholipids-binding protein group found in many diverse eukaryotic organisms. Although earlier studies have shown that CPNE6 is almost exclusively expressed in brain, the exact biological functions remain unclear. The purpose of this study is to explore the relationship between epilepsy and CPNE6 expression. In present study, we investigated the expression pattern and distribution of CPNE6 in patients with refractory epilepsy and in a chronic pilocarpine-induced epileptic rat model by quantitative real-time PCR, Western blot and immunofluorescence. The results showed that the expression of CPNE6 increased remarkably in epileptic patients and in experimental epileptic rats. Double immunofluorescence labeling studies have revealed that CPNE6 protein is mainly expressed in neurons, demonstrated by co-localization with the dendritic marker, MAP2. Our results are the first to indicate that the abnormal expression of the CPNE6 in epileptic brain tissue may play an important role in epilepsy, especially refractory epilepsy.