Nanchang University, People's Republic of China.
Apoptosis. 2010 Jun;15(6):693-704. doi: 10.1007/s10495-010-0477-9.
Excess apoptosis of endothelial cells (EC) plays crucial roles in the onset and progression of vasculopathy in diabetes mellitus. Anion exchanger-2 (AE2) might be involved in the vasculopathy. However, little is known about the molecular mechanisms that AE2 mediated the apoptosis of EC. The purpose of this study was to explore the role of AE2 in the apoptosis of HUVECs induced by high glucose (HG) and its possible mechanisms. First, HUVECs were exposed to different glucose concentrations (5.5, 17.8, 35.6, 71.2 and 142.4 mmol/l, respectively, pH = 7.40) for different time points (12, 24, 48, 72, 120, and 168 h, respectively). Intracellular Cl(-) concentration ([Cl(-)]i), AE2 expression and the apoptosis were assayed. Then, 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), Cl(-)-free media or specific RNA interference (RNAi) for AE2 was used to confirm whether AE2 could mediate the apoptosis induced by HG. Finally, the mechanisms of the AE2-mediated apoptosis were investigated by detecting mitochondrial permeability transition pore (mPTP, DeltaPsim) openings, reactive oxygen species (ROS) levels and Caspase-3 activity. We found that HG upregulated the AE2 expression and activity, increased [Cl(-)]i and induced the apoptosis in a time- and concentration-dependent manner. The apoptosis of HUVECs by HG was possibly mediated by AE2 through an mPTP-ROS-Caspase-3 dependent pathway. These findings suggested that AE2 was likely to be a glucose-sensitive transmembrane transporter and a novel potential therapeutic target for diabetic vasculopathy.
内皮细胞（EC）的过度凋亡在糖尿病血管病变的发生和发展中起着关键作用。阴离子交换蛋白 2（AE2）可能参与了血管病变。然而，AE2 介导 EC 凋亡的分子机制知之甚少。本研究旨在探讨 AE2 在高糖（HG）诱导的 HUVEC 凋亡中的作用及其可能的机制。首先，将 HUVEC 暴露于不同的葡萄糖浓度（分别为 5.5、17.8、35.6、71.2 和 142.4mmol/l，pH=7.40）和不同的时间点（分别为 12、24、48、72、120 和 168h）。测定细胞内 Cl(-)浓度([Cl(-)]i)、AE2 表达和细胞凋亡。然后，使用 4,4'-二异硫氰酸基二苯乙烯-2,2'-二磺酸（DIDS）、无 Cl(-)培养基或针对 AE2 的特异性 RNA 干扰（RNAi）来确认 AE2 是否可以介导 HG 诱导的凋亡。最后，通过检测线粒体通透性转换孔（mPTP，DeltaPsim）开放、活性氧（ROS）水平和 Caspase-3 活性来研究 AE2 介导凋亡的机制。结果发现，HG 呈时间和浓度依赖性地上调 AE2 的表达和活性，增加[Cl(-)]i，并诱导 HUVEC 凋亡。HG 诱导的 HUVEC 凋亡可能通过 mPTP-ROS-Caspase-3 依赖性途径介导。这些发现表明，AE2 可能是一种葡萄糖敏感的跨膜转运蛋白，是糖尿病血管病变的一个新的潜在治疗靶点。
