ClC-3 Expression and Its Association with Hyperglycemia Induced HT22 Hippocampal Neuronal Cell Apoptosis.

Feiyan Fan,Xin Wang,Hui Liu,Yanyang Tu,Nan Liu,Qian Li,Zhen Wang,Pengxing Zhang,Tao Liu,Jianfang Fu,Dongni Ren

doi:10.1155/2016/2984380

Feiyan Fan, Xin Wang + Show 9 more

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https://doi.org/10.1155/2016/2984380

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Abstract

Although apoptosis plays an important role in the development of Diabetic Encephalopathy (DE), the underlying molecular mechanisms remain unclear. With respect to this, the present work aims to study the variation in chloride/proton exchanger ClC-3 expression and its association with HT22 hippocampal neuronal apoptosis under hyperglycemic condition in vitro. The cells were stimulated with added 0, 5, or 25 mM glucose or mannitol for up to 72 hours before assessing the rate of ClC-3 expression, cell viability, and apoptosis. In a consecutive experiment, cells received chloride channel blocker in addition to glucose. The rate of cellular death/apoptosis and viability was measured using Flow Cytometry and MTT assay, respectively. Changes in ClC-3 expression were assessed using immunofluorescence staining and western blot analysis. The results revealed a significant increase in cellular apoptosis and reduction in viability, associated with increased ClC-3 expression in high glucose group. Osmolarity had no role to play. Addition of chloride channel blocker completely abolished this effect. Thus we conclude that, with its increased expression, ClC-3 plays a major role in hyperglycemia induced hippocampal neuronal apoptosis. To strengthen our understanding of this aforesaid association, we conducted an extensive literature search which is presented in this paper.

Highlights

For a long time, central nervous system (CNS), being an insulin independent organ, was thought to be spared from complications of diabetes mellitus (DM)
The observation under an inverted light microscope showed a normal morphology of HT22 cells under control groups and under low glucose group (30 mM glucose stimulation)
Supplementing with additional 25 mM glucose to the basal DMEM-HG medium affected the normal growth of HT22 cells, as appreciated under light microscope

Summary

Introduction

Central nervous system (CNS), being an insulin independent organ, was thought to be spared from complications of diabetes mellitus (DM). In recent decades, various studies have changed this perception by revealing the degenerative response of CNS in chronic DM condition, a condition referred to as Diabetic Encephalopathy (DE), characterized by cognitive dysfunction and failure of learning and memory [1,2,3,4]. Chloride (Cl−) channels are transmembrane proteins in biological membranes, which form functional pores and allow the diffusion of negatively charged Cl− ions along the electrochemical gradients. These channels can conduct other anions including I−, Br−, tamate.

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