Ion Transport in a Human Lens Epithelial Cell Line Exposed to Hyposmotic and Apoptotic Stress
Ion Transport in a Human Lens Epithelial Cell Line Exposed to Hyposmotic and Apoptotic Stress
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DOI：
10.1002/jcp.22015
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发表时间：
2010-04-01
影响因子：
5.6
通讯作者：
Lauf, Peter K.
中科院分区：
文献类型：
--
作者：
Chimote, Ameet A.;Adragna, Norma C.;Lauf, Peter K.
比较了人透镜上皮细胞（HLE-B3）在低渗和凋亡胁迫下膜转运的变化。在低渗诱导的低渗应激和蛋白激酶抑制剂staurosporine（STP）诱导的凋亡应激后，测定细胞钾含量、K-i、K同系物铷的摄取、Rb-i和水含量。与等渗（300 mOsm）平衡盐溶液（BSS）相比，低渗（150 mOsm）平衡盐溶液（BSS）中的细胞水在5分钟时增加>2倍，并在15分钟内降低至基线值，伴随着40%的Ki损失，与细胞肿胀相称，随后可能由于调节性体积减少（RVD）导致细胞收缩。克霉唑（CTZ）阻止了低渗BSS中Ki和伴随的水和RI的损失;表明水移位与通过中间电导K（IK）通道的K和Rb通量相关，也在mRNA和蛋白质水平检测到。相反，在2 μ MSTP暴露后2小时，细胞分别损失类似于40%的水和类似于60%Ki，与凋亡体积减少（AVD）一致。事实上，低渗后水和Ki损失比凋亡应激后大至少五倍。高细胞外钾和2 mM 4-氨基吡啶（4-AP），但没有CTZ显着减少细胞凋亡。膜联蛋白标记的磷脂酰丝氨酸（PS）在15分钟的脂质不对称性的损失。定量PCR显示，在长期的低渗应激IK通道的表达显着。结果表明，在HLE-B3细胞中，IK通道可能参与RVD后下调，而促凋亡STP激活的4-AP敏感的电压门控K通道之前或伴随PS外化之前，随后的凋亡。J.细胞。223：110-122，2010。(C)2010 Wiley-Liss，Inc.
Membrane transport changes in human lens epithelial (HLE-B3) cells under hyposmotic and apoptotic stress were compared. Cell potassium content, K-i, uptake of the K congener rubidium, Rb-i, and water content were measured after hyposmotic stress induced by hypotonicity, and apoptotic stress by the protein-kinase inhibitor staurosporine (STP). Cell water increased in hyposmotic (150 mOsm) as compared to isosmotic (300 mOsm) balanced salt solution (BSS) by >2-fold at 5 min and decreased within 15 min to baseline values accompanied by a 40% K-i loss commensurate with cell swelling and subsequent cell shrinkage likely due to regulatory volume decrease (RVD). Loss of K-i, and accompanying water, and RI); uptake in hyposmotic BSS were prevented by clotrimazole (CTZ) suggesting water shifts associated with K and Rb flux via intermediate conductance K (IK) channels, also detected at the mRNA and protein level. In contrast, 2 h after 2 mu M STP exposure, the cells lost similar to 40% water and similar to 60% K-i, respectively, consistent with apoptotic volume decrease (AVD). Indeed, water and K-i loss was at least fivefold greater after hyposmotic than after apoptotic stress. High extracellular K and 2 mM 4-aminopyridine (4-AP) but not CTZ significantly reduced apoptosis. Annexin labeling phosphatidylserine (PS) at 15 min suggested loss of lipid asymmetry. Quantitative PCR revealed significant IK channel expression during prolonged hyposmotic stress. Results suggest in HLE-B3 cells, IK channels likely partook in and were down regulated after RVD, whereas pro-apoptotic STP-activation of 4-AP-sensitive voltage-gated K channels preceded or accompanied PS externalization before subsequent apoptosis. J. Cell. Physiol. 223: 110-122, 2010. (C) 2010 Wiley-Liss, Inc.