Villin promoter-mediated transgenic expression of transient receptor potential cation channel, subfamily V, member 6 (TRPV6) increases intestinal calcium absorption in wild-type and vitamin D receptor knockout mice
Villin promoter-mediated transgenic expression of transient receptor potential cation channel, subfamily V, member 6 (TRPV6) increases intestinal calcium absorption in wild-type and vitamin D receptor knockout mice
复制标题
DOI：
10.1002/jbmr.1662
复制
发表时间：
2012-10-01
影响因子：
6.2
通讯作者：
Fleet, James C.
中科院分区：
文献类型：
--
作者：
Cui, Min;Li, Qiang;Fleet, James C.
瞬时受体电位阳离子通道，亚科 V，成员 6 (TRPV6) 是小肠中的顶膜钙 (Ca) 通道，被认为对于维生素 D 调节肠道 Ca 吸收至关重要。最近的研究对 TRPV6 在 Ca 吸收中的作用提出了质疑。我们直接测试了野生型 (WT) 和维生素 D 受体敲除 (VDRKO) 小鼠的肠道 TRPV6 在 Ca 和骨代谢中的功能。 TRPV6 转基因小鼠 (TG) 是用肠上皮特异性表达 3X Flag 标记的人 TRPV6 蛋白制成的。 TG 和 VDRKO 小鼠杂交产生 TG-VDRKO 小鼠。在 WT、TG、VDRKO 和 TG-VDRKO 小鼠中检查了 Ca 和骨代谢。 TG 小鼠在进食食物后出现高钙血症和软组织钙化。在饲喂 0.25% Ca 饮食的 TG 小鼠中，Ca 吸收量比 WT 小鼠高出三倍多，股骨骨矿物质密度 (BMD) 高出 26%。在 TG 小鼠中，肾 1a 羟化酶 (CYP27B1) mRNA 和天然小鼠 TRPV6 基因的肠道表达减少至 15 倍。 TG-VDRKO 小鼠具有高 Ca 吸收，可防止 VDRKO 小鼠中出现的低血清 Ca、高肾 CYP27B1 mRNA、低 BMD 和异常骨微结构。此外，TG-VDRKO 中小肠钙结合蛋白 D9K mRNA 和蛋白水平升高。即使在 VDRKO 小鼠中，肠道中的转基因 TRPV6 表达也足以增加钙吸收和骨密度。 TG-VDRKO 中肠钙结合蛋白 D9k 的 VDR 依赖性上调表明该蛋白可能在 Ca 吸收过程中缓冲细胞内 Ca。 (c) 2012 年美国骨与矿物质研究学会。
Transient receptor potential cation channel, subfamily V, member 6 (TRPV6) is an apical membrane calcium (Ca) channel in the small intestine proposed to be essential for vitamin Dregulated intestinal Ca absorption. Recent studies have challenged the proposed role for TRPV6 in Ca absorption. We directly tested intestinal TRPV6 function in Ca and bone metabolism in wild-type (WT) and vitamin D receptor knockout (VDRKO) mice. TRPV6 transgenic mice (TG) were made with intestinal epitheliumspecific expression of a 3X Flag-tagged human TRPV6 protein. TG and VDRKO mice were crossed to make TG-VDRKO mice. Ca and bone metabolism was examined in WT, TG, VDRKO, and TG-VDRKO mice. TG mice developed hypercalcemia and soft tissue calcification on a chow diet. In TG mice fed a 0.25% Ca diet, Ca absorption was more than three-fold higher and femur bone mineral density (BMD) was 26% higher than WT. Renal 1a hydroxylase (CYP27B1) mRNA and intestinal expression of the natural mouse TRPV6 gene were reduced to 15 times in TG mice. TG-VDRKO mice had high Ca absorption that prevented the low serum Ca, high renal CYP27B1 mRNA, low BMD, and abnormal bone microarchitecture seen in VDRKO mice. In addition, small intestinal calbindin D9K mRNA and protein levels were elevated in TG-VDRKO. Transgenic TRPV6 expression in intestine is sufficient to increase Ca absorption and bone density, even in VDRKO mice. VDR-independent upregulation of intestinal calbindin D9k in TG-VDRKO suggests this protein may buffer intracellular Ca during Ca absorption. (c) 2012 American Society for Bone and Mineral Research.