Bial, Eisai, GlaxoSmithKline, Janssen-Cilag, Novartis, Pfizer, Sanofi-Aventis, UCB, the Netherlands Epilepsy Foundation, and Stockholm County Council.

Although microorganisms play a role in gut inflammation, it remains uncertain which epithelial genes are expressed in response to luminal flora and whether these molecules are also involved in pathologic mucosal inflammation. Germ-free mice were orally challenged with a bacterial suspension prepared from conventionally housed mice (bacterial reconstitution). Thereafter, the differential gene expression in gut epithelial cells was identified by differential display. The expression of the identified genes was also examined in dextran sulfate sodium (DSS)-induced colitis and human inflammatory bowel disease (IBD) epithelial cells. Regenerating gene III (Reg III) was strongly induced in gut epithelial cells following bacterial reconstitution, as well as in the colitis initiated by DSS. The mRNA expression of hepatocarcinoma-intestine-pancreas/pancreatic associated protein (HIP/PAP), a human counterpart of Reg III, was enhanced in colonic epithelial cells of patients with IBD. Reg III mRNA expression was localized in the epithelial cells including goblet cells and columnar cells in mice; on the other hand, HIP/PAP-expressing cells were correlated with Paneth cell metaplasia in human colon. Epithelial expression of Reg III or HIP/PAP was induced under mucosal inflammation initiated by exposure to commensal bacteria or DSS as well as inflamed IBD colon.

Mutations in the SCN2A gene encoding a voltage-gated sodium channel Nav1.2 are associated with epilepsies, intellectual disability, and autism. SCN2A gain-of-function mutations cause early-onset severe epilepsies, while loss-of-function mutations cause autism with milder and/or later-onset epilepsies. Here we show that both heterozygous Scn2a-knockout and knock-in mice harboring a patient-derived nonsense mutation exhibit ethosuximide-sensitive absence-like seizures associated with spike-and-wave discharges at adult stages. Unexpectedly, identical seizures are reproduced and even more prominent in mice with heterozygous Scn2a deletion specifically in dorsal-telencephalic (e.g., neocortical and hippocampal) excitatory neurons, but are undetected in mice with selective Scn2a deletion in inhibitory neurons. In adult cerebral cortex of wild-type mice, most Nav1.2 is expressed in excitatory neurons with a steady increase and redistribution from proximal (i.e., axon initial segments) to distal axons. These results indicate a pivotal role of Nav1.2 haplodeficiency in excitatory neurons in epilepsies of patients with SCN2A loss-of-function mutations.

SUMMARYPurpose: To survey the treatment situation of Dravet syndrome in Japan and to compare this result with effectiveness of stiripentol (STP) addon therapy in an open-label multicenter study. Methods: Medical records of patients with Dravet syndrome who visited the study institutions during 2006 were surveyed to examine the effect of antiepileptic drugs (AEDs) on clonic or tonic-clonic seizures (GTCS). Patients older than 1 year of age treated with at least one conventional AED and more than four GTCS per month were invited to participate in the STP study. Seizure status and adverse effects during the first 4 weeks of STP (50 or 1,000 mg/day) add-on therapy (early period) and during long-term treatment were compared with baseline. Results: Only 15% of the treatment trials with 15 conventional AEDs in 112 patients succeeded in reducing seizures by more than 50%. With STP, GTCS were reduced more than 50% in 14 of 23 patients (61%), including 2 who became seizurefree, in the early period. Moreover, duration of seizures was shortened in 10 patients and status epilepticus decreased in 6. These effects continued in the long-term although to a lesser degree. Adverse effects (loss of appetite, sleep disturbance, ataxia, hyperactivity/irritability) disappeared after dose modification in most cases.

Summary Dravet syndrome is a severe form of epileptic encephalopathy characterized by early onset epileptic seizures followed by ataxia and cognitive decline. Approximately 80% of patients with Dravet syndrome have been associated with heterozygous mutations in SCN1A gene encoding voltage‐gated sodium channel (VGSC) αI subunit, whereas a homozygous mutation (p.Arg125Cys) of SCN1B gene encoding VGSC βI subunit was recently described in a patient with Dravet syndrome. To further examine the involvement of homozygous SCN1B mutations in the etiology of Dravet syndrome, we performed mutational analyses on SCN1B in 286 patients with epileptic disorders, including 67 patients with Dravet syndrome who have been negative for SCN1A and SCN2A mutations. In the cohort, we found one additional homozygous mutation (p.Ile106Phe) in a patient with Dravet syndrome. The identified homozygous SCN1B mutations indicate that SCN1B is an etiologic candidate underlying Dravet syndrome.

The innate immune system constitutes the front line of host defense against pathogens. Toll-like receptors (TLRs) recognize molecules derived from pathogens and play crucial roles in the innate immune system. Here, we provide evidence that the TLR-related genes have come under natural selection pressure in the course of primate evolution. We compared the nucleotide sequences of 16 TLR-related genes, including TLRs (TLR1-10), MYD88, TILAP, TICAM1, TICAM2, MD2, and CD14, among seven primate species. Analysis of the non-synonymous/synonymous substitution ratio revealed the presence of both strictly conserved and rapidly evolving regions in the TLR-related genes. The genomic segments encoding the intracellular Toll/interleukin 1 receptor domains, which exhibited lower rates of non-synonymous substitution, have undergone purifying selection. In contrast, TLR4, which carried a high proportion of non-synonymous substitutions in the part of extracellular domain spanning 200 amino acids, was found to have been the suggestive target of positive Darwinian selection in primate evolution. However, sequence analyses from 25 primate species, including eight hominoids, six Old World monkeys, eight New World monkeys, and three prosimians, showed no evidence that the pressure of positive Darwinian selection has shaped the pattern of sequence variations in TLR4 among New World monkeys and prosimians.

Mutations involving the voltage-gated sodium channel alpha(I) gene SCN1A are major genetic causes of childhood epileptic disorders, as typified by Dravet syndrome. Here we investigated the upstream regions of the SCN1A 5' noncoding exons and found two major regions with promoter activity. These two major promoters were simultaneously active in various brain regions and in most neurons. Using multiplex ligation-dependent probe amplification (MLPA) assays with probes for the 5' noncoding exons, their upstream regions, and all coding exons of SCN1A, we investigated 130 epileptic patients who did not show any SCN1A mutations by sequence analysis of all coding exons and exon-intron boundaries. Among 71 Dravet syndrome patients, we found two patients with heterozygous microdeletions removing the 5' noncoding exons and regions with promoter activity but not affecting the coding exons. We also identified four patients with deletions/duplication in the coding region. One patient with symptomatic focal epilepsy also showed a deletion in the coding region. This study provides the first case of microdeletion limited to the SCN1A 5' promoter region with the coding sequence preserved, and indicates the critical involvement of this upstream region in the molecular pathology of Dravet syndrome.

SUMMARYPurpose: We previously reported a mutant mouse carrying a severe myoclonic epilepsy in infancy (SMEI) mutation in Scn1a. In this study, we examined the susceptibility to hyperthermia-induced seizures of heterozygous Scn1a mutant mice (Scn1a RX/+) and wild-type (Scn1a +/+ ) mice. Then we assessed the efficacy of stiripentol (STP) monotherapy versus STP and clobazam (CLB) combination therapy to prevent hyperthermia-induced seizures in Scn1a RX/+ mice. Methods: The seizure-inducing body temperatures in Scn1a RX/+ mice and age-matched Scn1a +/+ mice were compared in three age groups (1 month, 3-5 months, > 6 months). Then STP, CLB, or STP + CLB was administered intraperitoneally to Scn1a RX/+ mice of two age groups (p1M, aged 1 month; p5M, aged 5-10 months). The efficacy of medications was assessed by comparing the seizure-inducing body temperature and the duration of seizures.Key Findings: The seizure-inducing body temperature was significantly lower in Scn1a RX/+ than in Scn1a +/+ mice for all age groups (p < 0.01). The seizure-inducing body temperature was significantly elevated after administration of STP in p1M (p < 0.05) but not in p5M (p > 0.05), and it was significantly elevated after administration of CLB in both age groups (p < 0.05). The seizure-inducing body temperature was significantly higher after administration of STP + CLB than after administration of CLB in p5M (p < 0.05). Significance: Scn1a RX/+ mice have increased susceptibility to hyperthermia-induced seizure in all age groups. STP monotherapy is effective in preventing hyperthermiainduced seizures in Scn1a RX/+ mice aged 1 month, but not in those aged 5 months and older. When used in combination therapy with CLB, STP inhibits the metabolism of CLB and probably synergistically enhances the anticonvulsant effect in mice aged 1 month.