Investigation of MicroRNA-134 as a Target against Seizures and SUDEP in a Mouse Model of Dravet Syndrome

Abstract

Dravet Syndrome (DS) is a catastrophic form of paediatric epilepsy mainly caused by non-inherited mutations in the SCN1A gene. DS patients suffer severe and life-threatening focal and generalised seizures which are often refractory to available anti-seizure medication. Antisense oligonucleotides (ASOs) based approaches may offer treatment opportunities in DS. MicroRNAs are short non-coding RNAs that play a key role in brain structure and function by post-transcriptionally regulating gene expression, including ion channels.Inhibiting microRNA-134 (miR-134) using an antimiR ASO (Ant-134) has been shown to reduce evoked seizures in juvenile and adult mice and reduce epilepsy development in models of focal epilepsy. The present study investigated the levels of miR-134 and whether Ant-134 could protect against hyperthermia-induced seizures, spontaneous seizures and mortality (SUDEP) in F1.Scn1a(+/-) tm1kea mice. At P17, animals were intracerebroventricular injected with 0.1 -1 nmol of Ant-134 and subject to a hyperthermia challenge at P18. A second cohort of P21 F1.Scn1a(+/-) tm1kea mice received Ant-134 and were followed by video and EEG monitoring until P28 to track the incidence of spontaneous seizures and SUDEP. Hippocampal and cortical levels of miR-134 were similar between wildtype and F1.Scn1a(+/-) tm1kea mice. Moreover, Ant-134 had no effect on hyperthermia-induced seizures, spontaneous seizures and SUDEP incidence were unchanged in Ant-134 treated DS mice. These findings suggest that targeting miR-134 does not have therapeutic applications in DS. 2 Significance StatementSeveral preclinical models of epilepsy have implicated miR-134 as a therapeutic target for seizure control and anti-epileptogenesis. The present study here explored whether targeting miR-134 has effects on seizures and mortality in a mouse model of Dravet Syndrome. The results indicate that suppression of miR-134 using an antimiR did not protect against hyperthermiainduced seizures, spontaneous seizures or SUDEP in F1.Scn1a(+/-) tm1kea mice.The findings suggest that miR-134 is not a therapeutic target in DS.

Intracerebroventricular administration for delivery of antiseizure therapeutics: Challenges and opportunities

“…76 In contrast, Ant-134 showed no therapeutic benefit in Scn1a +/− mice (modeling Dravet syndrome). 77 Yet in another study, a single dose of the ASO administered ICV to Scn1a +/− mice was associated with increased productive mRNA transcript, increased levels in the brain of the NaV1.1 protein (the sodium channel subunit encoded by Scn1a), and significantly reduced incidence of sudden unexpected death in epilepsy (SUDEP; Table 1). 78 These findings, together with those from intrathecal administration of the ASO in other species, provided the basis for a clinical trial with the ASO-based therapy STK-001 (administered intrathecally) in patients with Dravet syndrome.…”

“…ICV administration of an ASO targeting microRNA‐134 alleviated seizures in mice with kainic acid‐induced seizures 75 and in a genetic murine model of Angelman syndrome 76 . In contrast, Ant‐134 showed no therapeutic benefit in Scn1a +/− mice (modeling Dravet syndrome) 77 . Yet in another study, a single dose of the ASO administered ICV to Scn1a +/− mice was associated with increased productive mRNA transcript, increased levels in the brain of the NaV1.1 protein (the sodium channel subunit encoded by Scn1a ), and significantly reduced incidence of sudden unexpected death in epilepsy (SUDEP; Table 1).…”

RNA therapeutics for epilepsy: An emerging modality for drug discovery

“…Decrease in pyramidal neuron spines in CA3; SE: reduction in severity and neuronal death, TLE: reduction in SRS, neuron loss, and hippocampal reorganization Academic [21] 30 mg/kg IP: long-lasting reduction in number and duration of SRS up to 3 months after injection, higher number of PV+ neurons, reduced astrogliosis, Limk1 antagonism partly obliterated effects of antagomir-134 Academic [22] PTZ: decrease in seizure duration, total power, and Racine score; increase in time to seizure onset PPS: no difference in SE severity; significant decrease in development of SRS Academic [23] .1 nmol: reduction in total EEG power, delay in seizure onset, lower percentage of mice experiencing full SE, reduced neuronal death in hippocampus, lower microgliosis, increased protein levels of DCX, no difference in Limk1 and Creb1 .05 and .5 nmol did not show the same protective properties Academic [76] Reduced proportion of mice that developed SE, delayed seizure onset of seizures, decreased total EEG power, no difference in frequency and spike counts Academic [25] Reduction in neuronal death and apoptosis, restoration of CREB expression and inhibition of ER stress, reduction in Mossy fiber sprouting, abnormal neuronal discharge, and seizure behavior Academic [26] No changes in temperature threshold, duration, and severity of hyperthermia-induced seizures; no change in frequency of SRS and SUDEP Academic [77] Reduced audiogenic seizure severity [78] Alleviation neuronal damage in the CA1 and CA3, reduced MDA, proinflammatory cytokines, GFAP, and increased SOD and Notch-1 pathway of hippocampus Academic [28] Increased latency to first seizures and decreased frequency and duration of seizures, and complement factor H in hippocampus Academic [30] Increased percentage of no induced seizures and latency to generalized convulsion and reduced seizure severity, lower hippocampal levels of NF-κB and cytokines, as well as neuronal damage Academic [31] Antagomir: shorter latency to SE onset, increased severity grade and hippocampal cytokines/TLR4/NF-κB Mimic: longer latency to SE onset, decreased severity grade and hippocampal cytokines/Tlr4/NF-κB…”

Retracted: Clinical and genetic evaluations of rare childhood epilepsies in Turkey's national cohort

“…Nav1.1 channel in inhibitory interneurons. [37][38][39][40] Vinpocetine, an alkaloid that amplifies GABA-evoked currents, has been used successfully to treat LGS caused by the GABRB3 mutation. 41 The novel compounds MPX-004 and MPX-007 have been developed to selectively block NMDA receptors containing the NR2A subunit in patients with a gain of function mutations in GRIN2A.…”