| Objective:Febrile seizures (FS) are the most common type of convulsive events in infants and young children. Research shows that FS are a multifactorial and polygenic disease, including ion channel, inflammation and so on, but their genetic basis remains elusive. We aim to identify novel susceptibility genes and investigate molecular mechanisms of FS. Our results will contribute to better illuminate the molecular mechanisms of FS, which may represent a significant step towards finding novel FS susceptibility genes and may shed light on the pathogenesis of FS.Methods:(1) We developed a novel rat model of FS, using classical model of hyperthermia-induced seizures combined with selective breeding procedures.(2) Basal excitability changes were addressed between two genotypes by kainic acid (KA)-induced seizures and electroencephalography (EEG).(3) RNA from hippocampal tissues was processed on whole genome microarrays. Genes differentially expressed between the two genotypes were identified (P value<0.05, fold change>|1.5|). Microarray results were verified by quantitative Real-Time PCR (qRT-PCR) of10differentially expressed genes.(4) Rat model of FS were induced in wild-type SD rats at P21by a hot water bath with or without the pre-administration of DPP4inhibitor or NaCl. Subsequently, we recorded and analyzed the EEG power of the two rat groups.(5) DPP4gene DNA methylation levels between the two distinct phenotype rats were detected by the method of Bisulfite Sequencing PCR (BSP).Results:(1) We have developed two new strains of rats that are Hyperthermia-Prone (HP) and Hyperthermia-Resistant (HR). With each subsequent generation, the incidence of FS gradually increased in the HP group, but the results were the opposite in the HR group.(2) We found that HP rats experienced higher seizure severity following hyperthermia-induced and KA injections than their HR counterparts. (3) Moreover, microarray analysis revealed1140differentially expressed genes (DEGS)(602upregulated;538downregulated). Significant Gene Ontology (GO) and pathways generate a molecular network that may provide a framework for the mechanism of FS. The results revealed that these differentially expressed genes are involved in a variety of biological processes and pathways, including the following: positive regulation of the cAMP biosynthetic process, regulation of neurotransmitter secretion, negative regulation of synaptic transmission, chronic inflammatory response to antigenic stimulus, steroid hormone biosynthesis, peroxisome proliferator-activated receptor (PPAR) signaling pathway, neuroactive ligand-receptor interaction pathway, metabolism of xenobiotics by cytochrome P450, arachidonic acid metabolism and so on.(4) Moreover, A total of38DEGS that may play pivotal roles in FS were obtained from gene co-expression network. Microarray results were verified by quantitative real-time PCR (qRT-PCR) of10DEGS, and sufficient consistency was observed between the two methods.(5) Dipeptidyl Peptidase4(DPP4) inhibitor can ease the seizure activity. Furthermore, DPP4gene DNA methylation levels in HP group were significantly higher than the HR group. The result suggested that epignetic regulation may play important role in the pathogenesis of FS.Conclusions:Rat model of FS suggested that epigenetic regulation may play an important role in the pathogenesis of FS. Meanwhile, microarray results suggested that many factors (immunity, ion channels, metabolism et.al) may paly a vital role in the pathogenesis of FS. Moreover, DPP4inhibitor can ease the seizures. The analysis of DPP4gene methylation indicated that DPP4gene expression may be regulated by epigenetic mechanisms in the pathogensis of FS. These results suggested that DPP4may merit further study as an attractive pharmacological target for the treatment of FS. |
PDF Full Text Request