Anomalous expression of chloride transporters in the sclerosed hippocampus of mesial temporal lobe epilepsy patients

The Na＋-K＋-CI- cotransporter 1 and K＋-CI- cotransporter 2 regulate the levels of intracellular chloride in hippocampal cells. Impaired chloride transport by these proteins is thought to be involved in the pathophysiological mechanisms of mesial temporal lobe epilepsy. Imbalance in the relative expression of these two proteins can lead to a collapse of CI- homeostasis, resulting in a loss of gamma-aminobutyric acid-ergic inhibition and even epileptiform discharges. In this study, we investigated the expression of Na＋-K＋-CI- cotransporter 1 and K＋-CI- cotransporter 2 in the sclerosed hippocampus of patients with mesial temporal lobe epilepsy, using western blot analysis and immunohistochemistry. Compared with the histologically normal hippocampus, the sclerosed hippocampus showed increased Na＋-K＋-Cl- cotransporter 1 expression and decreased K＋-CI- cotransporter 2 expression, especially in CA2 and the dentate gyrus. The change was more prominent for the Na＋-K＋-CI- cotransporter 1 than for the K＋-CI- cotransporter 2. These experimental findings indicate that the balance between intracellular and extracellular chloride may be disturbed in hippocampal sclerosis, contributing to the hyperexcitability underlying epileptic seizures. Changes in Na＋-K＋-CI-cotransporter 1 expression seems to be the main contributor. Our study may shed new light on possible therapies for patients with mesial temporal lobe epilepsy with hippocampal sclerosis.

PRRT2 gene and protein in human:characteristics,evolution and function

Background:This study was designed to characterize human PRRT2 gene and protein,in order to provide theoretical reference for research on regulation of PRRT2 expression and its involvement in the pathogenesis of paroxysmal kinesigenic dyskinesia and other related diseases.Method:Biological softwares Protparam,Protscale,MHMM,SignalP 5.0,NetPhos 3.1,Swiss-Model,Promoter 2.0,AliBaba2.1 and EMBOSS were used to analyze the sequence characteristics,transcription factors of human PRRT2 and their binding sites in the promoter region of the gene,as well as the physicochemical properties,signal peptides,hydrophobicity property,transmembrane regions,protein structure,interacting proteins and functions of PRRT2 protein.Results:(1)Evolutionary analysis of PRRT2 protein showed that the human PRRT2 had closest genetic distance from Pongo abelii.(2)The human PRRT2 protein was an unstable hydrophilic protein located on the plasma membrane.(3)The forms of random coil(67.65%)and alpha helix(23.24%)constituted the main secondary structure elements of PRRT2 protein.There were also multiple potential phosphorylation sites in the protein.(4)The results of ontology analysis showed that the cellular component of PRRT2 protein was located in the plasma membrane;the molecular function of PRRT2 included syntaxin-1 binding and SH3 domain binding;the PRRT2 protein is involved in biological processes of negative regulation of soluble NSF attachment protein receptor(SNAR E)complex assembly and calcium-dependent activation of synaptic vesicle fusion.(5)String database analysis revealed 10 proteins with close interactions with the human PRRT2 protein.(6)There were at least two promoter regions in the PRRT2 gene within 2000 bp upstream the 5'flank,a 304-bp CpG island in the promoter region and four GC boxes in the 5'regulatory region of PRRT2 gene and we found 13 transcription factors that could bind the promoter region of the PRRT2 gene.Conclusion:These results provide important information for further studies on the role of PRRT2 gene and identify their functions.