Gene expression analysis on anterior temporal neocortex of patients with intractable epilepsy

Abstract

To elucidate the molecular basis of intractable epilepsy (IE), we used a whole-genome transcriptomic approach to identify genes involved in the pathogenesis of this disease. Using a complementary DNAs microarray representing 4096 human genes, we analyzed differential gene expression in the anterior temporal neocortex (ATN) of IE patients relative to control patients who had an operation to relieve head trauma-related intracranial pressure. The results were validated by real-time fluorescence-quantitative polymerase chain reaction (FQ-PCR) and reverse transcription-PCR (RT-PCR). The expression of 143 genes (3.5%) was significantly altered in IE patients. Thirty-seven genes (26%) were reduced relative to controls, and 106 (74%) were elevated (more than twofold change vs. controls), including genes involved in immunity, signal transduction, apoptosis, stress, synaptic plasticity, structural, and cellular reorganization, among other processes. Results for 13 of the 14 differentially expressed genes tested by FQ-PCR were consistent with the microarray. Twelve abnormally expressed cytoskeletal genes were confirmed by RT-PCR. Expression of 11 was significantly higher in the ATN of IE patients than in controls. Gene products altered in IE, namely HSPBAP1, TRAP220, glycogen synthase kinase-3beta (GSK-3beta), and cyclin-dependent kinase 5 (CDK5), were tested by immunohistochemistry and immunoblotting. GSK-3beta and CDK5 levels were significantly higher in the ATN of IE patients. Our gene chip data are generally in agreement with the published findings on epilepsy. Thus, gene chips may serve as a screening tool to elucidate the pathophysiology of IE. Investigation of some of these newly identified genes should enhance our understanding of the molecular mechanisms of epileptogenesis.

Spontaneous Seizures and Altered Gene Expression in GABA Signaling Pathways in amind bombMutant Zebrafish

“…Seizure induced expression of activity-dependent CNS genes has been described in animal models and tissue obtained at surgery from patients with intractable forms of epilepsy (Hendriksen et al, 2001; Elliott et al, 2003; Hunsberger et al, 2005; Rakhade et al, 2005; Xi et al, 2009). One of these previously described genes, BDNF a member of the “neurotrophin” family of growth factors, is believed to play a role in synaptic plasticity and excitability (Croll et al, 1999; Cowansage et al, 2009).…”

“…Microarrays have been used extensively to identify molecular processes that may underlie acute or chronic seizure activity (Hendriksen et al, 2001; Elliott et al, 2003; Hunsberger et al, 2005; Rakhade et al, 2005; Xi et al, 2009). In the epileptic brain, up-regulation of numerous genes mediating cell injury or survival is expected given the well known damage that can occur with excessive electrical activity (Sloviter, 1996; Houser, 1999; Elliott et al, 2001).…”

DNA Methylation Mediates Persistent Epileptiform Activity In Vitro and In Vivo

“…Another unresolved question is what are the mechanisms responsible for the inter-individual variation in the chronic response to a transient epileptoform insult? Human and animal epilepsy studies show changes in gene expression profiles [38-40], suggesting that mechanisms involved in epileptogenesis are registered in the genome and that there must be genomic mechanisms that mediate the long-lasting changes in gene expression in response to transient neural insult.…”

Whole transcriptome analysis of the hippocampus: toward a molecular portrait of epileptogenesis

“…In epilepsy, the clinical implications of the microarray technology are illustrated in a few recent publications in the literature [5-9]. One drawback of such approach in humans, however, is that the experimental design is not trivial due to the lack of appropriate control samples of healthy brain tissue.…”