The neuronal K(+)Cl(-) co-transporter 2 (Slc12a5) modulates insulin secretion.
The neuronal K(+)Cl(-) co-transporter 2 (Slc12a5) modulates insulin secretion.
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DOI：
10.1038/s41598-017-01814-0
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发表时间：
2017-05-11
影响因子：
4.6
通讯作者：
Di Fulvio M
中科院分区：
文献类型：
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作者：
Kursan S;McMillen TS;Beesetty P;Dias-Junior E;Almutairi MM;Sajib AA;Kozak JA;Aguilar-Bryan L;Di Fulvio M
胰腺β细胞中的细胞内氯离子浓度（[Cl−]i）保持在电化学平衡以上，这是由于Cl−负载物（如Na+K+2Cl−共转运蛋白1（Slc 12 a2））在性质不明的Cl−挤出物上的主要功能存在。利用分子克隆、RT-PCR、Western印迹、免疫定位和体外功能测定，我们确定了“神经元特异性”K+Cl−协同转运蛋白2（KCC 2，Slc 12 a5）在胰岛的几种内分泌细胞中表达，包括胰高血糖素分泌α细胞，但特别是在胰岛素分泌β细胞中，我们为它在胰岛素分泌反应中的作用提供了证据。三个KCC 2剪接变异体被确定：以前描述的KCC 2a和KCC 2b沿着与一个新的一个缺乏外显子25（KCC 2a-S25）。这种新的变异在大脑或脊髓中无法检测到，这是KCC 2唯一和最丰富的已知来源。在存在格列本脲（ATP依赖性钾（KATP）通道抑制剂）的情况下，抑制克隆MIN 6 β细胞中的KCC 2活性可增加基础和葡萄糖刺激的胰岛素分泌和Ca 2+摄取，从而表明KCC 2依赖性胰岛素释放的可能机制。我们提出，长期认为的“神经元特异性”KCC 2协同转运蛋白在胰岛β细胞中表达，在胰岛β细胞中它调节Ca 2+依赖性胰岛素分泌。
Intracellular chloride concentration ([Cl−]i) in pancreatic β-cells is kept above electrochemical equilibrium due to the predominant functional presence of Cl− loaders such as the Na+K+2Cl− co-transporter 1 (Slc12a2) over Cl−extruders of unidentified nature. Using molecular cloning, RT-PCR, Western blotting, immunolocalization and in vitro functional assays, we establish that the “neuron-specific” K+Cl− co-transporter 2 (KCC2, Slc12a5) is expressed in several endocrine cells of the pancreatic islet, including glucagon secreting α-cells, but particularly in insulin-secreting β-cells, where we provide evidence for its role in the insulin secretory response. Three KCC2 splice variants were identified: the formerly described KCC2a and KCC2b along with a novel one lacking exon 25 (KCC2a-S25). This new variant is undetectable in brain or spinal cord, the only and most abundant known sources of KCC2. Inhibition of KCC2 activity in clonal MIN6 β-cells increases basal and glucose-stimulated insulin secretion and Ca2+ uptake in the presence of glibenclamide, an inhibitor of the ATP-dependent potassium (KATP)-channels, thus suggesting a possible mechanism underlying KCC2-dependent insulin release. We propose that the long-time considered “neuron-specific” KCC2 co-transporter is expressed in pancreatic islet β-cells where it modulates Ca2+-dependent insulin secretion.