Sodium/bicarbonate cotransporter NBCn1/slc4a7 increases cytotoxicity in magnesium depletion in primary cultures of hippocampal neurons.
Sodium/bicarbonate cotransporter NBCn1/slc4a7 increases cytotoxicity in magnesium depletion in primary cultures of hippocampal neurons.
复制标题
DOI：
10.1111/j.1460-9568.2008.06611.x
复制
发表时间：
2009-02
期刊：
影响因子：
--
通讯作者：
Choi I
中科院分区：
文献类型：
--
作者：
Cooper DS;Yang HS;He P;Kim E;Rajbhandari I;Yun CC;Choi I
越来越多的证据表明，药物抑制Na/H交换和Na/HCO3运输可保护心脏免受缺血损伤。在本研究中，我们检测了钠/碳酸氢盐共转运体NBCn1 （slc4a7）在培养大鼠海马神经元细胞毒性中的作用。在细胞外pH （pHo）范围为6.2至8.3的神经元中，pH < 6.5时NBCn1蛋白的表达比pHo 7.4时增加了5倍。pHo 6.5时，神经元胞内pH值比pHo 7.4时低1个单位。免疫化学结果显示，pHo为6.5时，胞质膜、胞质溶胶及树突内NBCn1免疫荧光明显增加。NBCn1的表达在正常pHo下无Mg2+的长时间培养中也增加了40%。神经元中NBCn1的敲低对细胞活力的影响可以忽略不计。然后通过将神经元暴露于0.5 mM谷氨酸中10分钟并测量神经元乳酸脱氢酶（LDH）的释放来确定NBCn1敲低对细胞毒性的影响。与谷氨酸暴露后的正常孵育（pHo 7.2 6小时）相比，酸性孵育（pHo 6.3 6小时）使对照神经元的细胞毒性降低75%，使nbcn1敲低神经元的细胞毒性降低78%。因此，对照组和敲除的神经元都表现出对细胞毒性的酸性保护。然而，在谷氨酸暴露后的无Mg2+培养中，NBCn1敲低逐渐减弱了细胞毒性。这种衰减不受谷氨酸暴露前的酸性预孵育的影响。我们得出结论，NBCn1在低pHo和Mg2+耗尽中具有动态上调。NBCn1不需要酸性保护，但在无Mg2+条件下增加细胞毒性。
Growing evidence suggests that pharmacological inhibition of Na/H exchange and Na/HCO3 transport provides protection against damage or injury in cardiac ischemia. In this study, we examined the contribution of the sodium/bicarbonate cotransporter NBCn1 (slc4a7) to cytotoxicity in cultured hippocampal neurons of rats. In neurons exposed to extracellular pH (pHo) ranging from 6.2 to 8.3, NBCn1 protein expression increased by fivefold at pH < 6.5 compared to the expression at pHo 7.4. At pHo 6.5, the intracellular pH of neurons was ~1 unit lower than that at pH 7.4. Immunochemistry showed a marked increase in NBCn1 immunofluorescence in plasma membranes and cytosol of the soma as well as in dendrites, at pHo 6.5. NBCn1 expression also increased by 40% in a prolonged Mg2+-free incubation at normal pHo. Knockdown of NBCn1 in neurons had negligible effect on cell viability. The effect of NBCn1 knockdown on cytotoxicity was then determined by exposing neurons to 0.5 mM glutamate for 10 min and measuring lactate dehydrogenase (LDH) release from neurons. Compared to normal incubation (pHo 7.2 for 6 h) after glutamate exposure, acidic incubation (pHo 6.3 for 6 h) reduced cytotoxicity by 75% for control neurons and 78% for NBCn1-knockdown neurons. Thus, both controls and knockdown neurons showed acidic protection from cytotoxicity. However, in Mg2+-free incubation after glutamate exposure, NBCn1 knockdown progressively attenuated cytotoxicity. This attenuation was unaffected by acidic preincubation before glutamate exposure. We conclude that NBCn1 has a dynamic upregulation in low pHo and Mg2+ depletion. NBCn1 is not required for acidic protection, but increases cytotoxicity in Mg2+-free conditions.
登录
查看更多内容
影响因子：
64.8
作者：
Choi, I;Aalkjaer, C;Boron, WF
通讯作者：
Boron, WF
DOI：
10.1152/ajpregu.00497.2007
发表时间：
2007-12-01
影响因子：
2.8
作者：
Chen, Li-Ming;Choi, Inyeong;Boron, Walter F.
通讯作者：
Boron, Walter F.
影响因子：
5.3
作者：
Giffard, RG;Papadopoulos, MC;Monyer, H
通讯作者：
Monyer, H
影响因子：
3
作者：
KOH, JY;CHOI, DW
通讯作者：
CHOI, DW
影响因子：
4.8
作者：
Cooper, DS;Saxena, NC;Choi, IY
通讯作者：
Choi, IY