MECHANISM OF NON-GENOMIC ACTION OF VITAMIN D

维生素 D 的非基因组作用机制

• 批准号: 2872223
• 负责人: KEITH A HRUSKA
• 金额: $ 21.15万
• 依托单位: BARNES-JEWISH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-02-01 至 2001-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2872223
• 关键词: 1,25 dihydroxycholecalciferol; antisense nucleic acid; calcium flux; calreticulin; carbohydrate biosynthesis; cell membrane; confocal scanning microscopy; cyclic nucleoside monophosphate; endoplasmic reticulum; enzyme activity; hormone regulation /control mechanism; inositol phosphates; intermolecular interaction; oligonucleotides; osteoblasts; protein kinase C; receptor binding; tissue /cell culture; transfection; vesicle /vacuole; vitamin D receptors

DESCRIPTION (Adapted from investigator's abstract): There no longer appears to be any question that the vitamin D metabolite, 1alpha,25- dihydroxyvitamin D3 (1alpha,25-(OH)2D3, calcitriol or CT), and its metabolic and synthetic analogs manifest nongenomic actions. Rapidly emerging evidence indicates that the nongenomic action plays important roles in controlling the mechanisms that underlie many diseases arising from disturbances in calcium homeostasis (e.g., osteoporosis), cell growth (breast carcinoma, psoriasis), cell differentiation and immune responses (possibly AIDS). The recent advent of noncalcemic, synthetic analogs has ushered in the realistic possibility of therapeutic use of these synthetic agents for the treatment of the above-mentioned diseases. The most prominent evidence for the nongenomic action of 1alpha,25- (OH)2D3 is stimulation of an acute, transient increase in the intracellular free calcium concentration ([Ca2+]I) and concomitant production of inositol polyphosphates. These are the first measurable manifestations that occur within one minute of cellular exposure to the agents. These actions closely resemble those of membrane (cell surface) receptor-agonist mediated mechanisms. However, the precise mechanisms by which vitamin D analogs induce the acute change in [Ca2+]I are unknown. The applicants' recent data demonstrate that the vitamin D receptor (VDR) binds to both plasma membrane (PM) and endoplasmic reticulum (ER). Furthermore, calreticulin (CRT) in the ER fraction is a specific acceptance protein for VDR. Since these two membranes constitute the major sites of [Ca2+]I control, the interaction between VDR and the membranes, and the role of the interaction in [Ca2+]I control must be clarified. Recent advances in cell biology (transfection technology), synthesis of vitamin D analogs with different biological properties and technologies related to the measurement of calcium fluxes in living cells, as well as in isolated membrane vesicles, make it now possible to logically investigate the problems at hand. Therefore, the Specific Aims of the proposed studies are to: 1) analyze the interaction of the VDR with the ER in order to elucidate the role of VDR/CT interaction on Ca2+ release from the ER and to determine the function of CRT in regulating intracellular Ca2+ stores; and 2) study the interaction of the VDR with the PM in order to elucidate the role of this interaction in acute Ca2+ influx stimulated by CT, and to identify a PM-specific acceptance protein for VDR.

描述（改编自研究者的摘要）：不再有 似乎是维生素 D 代谢物 1alpha,25- 的任何问题 二羟基维生素 D3（1α,25-(OH)2D3、骨化三醇或 CT）及其 代谢和合成类似物表现出非基因组作用。迅速 新出现的证据表明非基因组作用发挥着重要作用 在控制许多疾病发生的机制中发挥作用 由于钙稳态紊乱（例如骨质疏松症），细胞 生长（乳腺癌、牛皮癣）​​、细胞分化和免疫 反应（可能是艾滋病）。最近出现的非钙血症合成药物 类似物带来了治疗用途的现实可能性 这些合成药剂用于治疗上述疾病。 1alpha,25-非基因组作用的最突出证据 (OH)2D3 刺激急性、短暂的增加 细胞内游离钙浓度 ([Ca2+]I) 和伴随的 生产肌醇多磷酸盐。 这些是第一个可测量的 细胞暴露于该物质后一分钟内发生的表现 代理。这些作用与膜（细胞表面）的作用非常相似 受体激动剂介导的机制。然而，精确的机制 维生素 D 类似物引起 [Ca2+]I 急剧变化的原因是 未知。申请人最近的数据表明，维生素 D 受体 (VDR) 与质膜 (PM) 和内质结合 网状结构（ER）。此外，ER 部分中的钙网蛋白 (CRT) 是 VDR 的特异性接受蛋白。由于这两个膜 构成[Ca2+]I控制的主要位点， VDR 和膜，以及 [Ca2+]I 中相互作用的作用 必须明确控制。细胞生物学的最新进展（转染 技术），合成具有不同生物活性的维生素D类似物 与钙通量测量相关的特性和技术 在活细胞以及分离的膜囊泡中，立即制作 可以逻辑地调查手头的问题。 因此， 拟议研究的具体目标是：1）分析相互作用 VDR 与 ER 的结合，以阐明 VDR/CT 的作用 与 ER 释放 Ca2+ 的相互作用并确定其功能 CRT 调节细胞内 Ca2+ 储存； 2）研究 VDR 与 PM 的互动，以阐明 CT 刺激的急性 Ca2+ 流入中的这种相互作用，并确定 VDR 的 PM 特异性接受蛋白。