Age-dependent regulation of rat intestinal type IIb sodium-phosphate cotransporter by 1,25-(OH)2 vitamin D3
Age-dependent regulation of rat intestinal type IIb sodium-phosphate cotransporter by 1,25-(OH)2 vitamin D3
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DOI：
10.1152/ajpcell.00412.2001
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发表时间：
2002-03-01
影响因子：
5.5
通讯作者：
Ghishan, FK
中科院分区：
文献类型：
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作者：
Xu, H;Bai, LQ;Ghishan, FK
本研究旨在研究IIb型钠-无机磷酸(P-I)共转运体(Napi-IIb)在大鼠个体发育过程中的表达，以及1，25-(OH)(2)维生素D-3对Napi-IIb基因表达的影响。肠刷状缘膜泡(BBMvs)钠依赖的P-I吸收随增龄而减少，Napi-IIb基因的表达也随增龄而成比例下降。1，25-(OH)(2)维生素D-3治疗使乳鼠肠道BBMV P-I吸收增加2.5倍，成年大鼠增加2.1倍。1，25-(OH)(2)维生素D-3处理也使14日龄大鼠的Napi-IIb mRNA丰度增加了2倍，但对成年大鼠的mRNA表达没有影响。此外，在大鼠肠上皮(RIE)细胞中，1，25-(OH)(2)维生素D-3增加了Napi-IIb基因的mRNA丰度，这种作用被放线菌素D消除。此外，瞬时转染的RIE细胞中的人Napi-IIb基因启动子活性在1，25-(OH)(2)维生素D-3处理后显示出类似的1.6倍的增加。综上所述，我们证明了与年龄相关的肠道钠依赖P-I吸收减少与Napi-IIb基因表达减少有关。我们的数据还表明，1，25-(OH)(2)维生素D-3对乳鼠Napi-IIb表达的影响至少部分是通过基因转录来实现的。
The current studies were designed to characterize type IIb sodium-inorganic phosphate (P-i) cotransporter (NaPi-IIb) expression and to assess the effect of 1,25-(OH)(2) vitamin D-3 on NaPi-IIb gene expression during rat ontogeny. Sodium-dependent P-i absorption by intestinal brush-border membrane vesicles (BBMVs) decreased with age, and NaPi-IIb gene expression also decreased proportionally with age. 1,25-(OH)(2) vitamin D-3 treatment increased intestinal BBMV P-i absorption by similar to2.5-fold in suckling rats and by similar to2.1-fold in adult rats. 1,25-(OH)(2) vitamin D-3 treatment also increased NaPi-IIb mRNA abundance by similar to2-fold in 14-day-old rats but had no effect on mRNA expression in adults. Furthermore, in rat intestinal epithelial (RIE) cells, 1,25-(OH)(2) vitamin D-3 increased NaPi-IIb mRNA abundance, an effect that was abolished by actinomycin D. Additionally, human NaPi-IIb gene promoter activity in transiently transfected RIE cells showed similar to1.6-fold increase after 1,25-(OH)(2) vitamin D-3 treatment. In conclusion, we demonstrate that the age-related decrease in intestinal sodium-dependent P-i absorption correlates with decreased NaPi-IIb mRNA expression. Our data also suggest that the effect of 1,25-(OH)(2) vitamin D-3 on NaPi-IIb expression is at least partially mediated by gene transcription in suckling rats.