Vitamin D increases tight-junction conductance and paracellular Ca2+ transport in caco-2 cell cultures
Vitamin D increases tight-junction conductance and paracellular Ca2+ transport in caco-2 cell cultures
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DOI：
10.1152/ajpgi.1998.274.2.g389
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发表时间：
1998-02-01
影响因子：
4.5
通讯作者：
Peterlik, M
中科院分区：
文献类型：
--
作者：
Chirayath, MV;Gajdzik, L;Peterlik, M
我们通过测定跨上皮电阻（TEER）研究了1 α，25-二羟维生素D-3 [1，25（OH）（2）D-3]对细胞旁肠钙吸收的影响，TEER是融合Caco-2细胞培养物中紧密连接离子渗透性和双向跨上皮Ca-45（2+）通量的测量。在10（-11）和10（-8）M之间，1，25（OH）（2）D-3以剂量依赖性方式显著减弱TEER升高至与2，000相似的稳态水平Omega.cm 1，25（OH）（2）D-3的合成类似物，即1 α，25-二羟基-16-烯，23-炔-维生素D-3和1 α，25-二羟基-26，27-六氟-16-烯，23-炔-维生素D-3，表现出相似的生物效力，而它们的基因组无活性的1-脱氧同源物仅略微有效。维生素D对Caco-2细胞单层跨上皮电导的增强伴随着双向跨上皮Ca-45（2+）通量的显著增加。虽然1，25（OH）（2）D-3也诱导Caco-2细胞层顶端的Ca-45（2+）摄取，并上调钙结合蛋白-9kDa mRNA的表达，但未检测到Ca ~（2+）-腺苷三磷酸酶介导的跨细胞途径对跨上皮Ca ~（2+）转运的显著贡献。因此，刺激跨汇合Caco-2细胞的Ca 2+通量很可能是由于维生素D甾醇对紧密连接复合物的组装和渗透性的基因组效应。
We investigated the effects of 1 alpha,25-dihydroxyvitamin D-3 [1,25(OH)(2)D-3] on paracellular intestinal Ca2+ absorption by determination of transepithelial electric resistance (TEER), as a measure of tight-junction ion permeability and bidirectional transepithelial Ca-45(2+) fluxes in confluent Caco-2 cell cultures. The rise of TEER to steady-state levels of similar to 2,000 Omega.cm(2) was significantly attenuated by 1,25(OH)(2)D-3 (by up to 50%) in a dose-dependent fashion between 10(-11) and 10(-8) M. Synthetic analogs of 1,25(OH)(2)D-3, namely, 1 alpha,25-dihydroxy-16-ene,23-yne-vitamin D-3 and 1 alpha,25-dihydroxy-26,27-hexafluoro-16-ene,23-yne-vitamin D-3, exhibited similar biopotency, whereas their genomically inactive l-deoxy congeners were only marginally effective. Enhancement of transepithelial conductance of Caco-2 cell monolayers by vitamin D was accompanied by a significant increase in bidirectional transepithelial Ca-45(2+) fluxes. Although 1,25(OH)(2)D-3 also induced cellular Ca-45(2+) uptake from the apical aspect of Caco-2 cell layers and upregulated the expression of calbindin-9kDa mRNA, no significant contribution of the Ca2+-adenosinetri-phosphatase-mediated transcellular pathway to transepithelial Ca2+ transport could be detected. Therefore stimulation of Ca2+ fluxes across confluent Caco-2 cells very likely results from a genomic effect of vitamin D sterols on assembly and permeability of tight-junctional complexes.