拉喹莫德抑制成骨细胞中缺氧诱导因子2α的表达及其功能  

Laquinimod inhibits the expression and function of hypoxia-inducible factor-2 alpha in osteoblasts

作　　者：赵光宗[1] 方军[1] 丁刚[1] 张龙强[1] 李华壮[1] 高克海[1] 

机构地区：[1]潍坊市益都中心医院骨科,山东省潍坊市252600

出　　处：《中国组织工程研究》2016年第7期917-924,共8页Chinese Journal of Tissue Engineering Research

基　　金：潍坊医学院药理教研室;病理教研室的大力支持与帮助

摘　　要：背景:由于骨折会诱导骨细胞缺氧,使骨细胞中的氧张力明显下降,现已证明,其中低氧诱导因子2α是机体在低氧状态下调剂机体功能的一种重要氧依赖转录激活因子,其介导骨折发生时多种炎性因子的释放。目的:探讨拉喹莫德对成骨细胞中缺氧诱导因子2α的表达和功能的影响。方法:缺氧处理前分别在蛋白酶体抑制剂MG132或N-乙酰基-亮氨酰-亮氨酰-正亮氨酸存在和不存在的情况下,用10-100μmol/L的拉喹莫德处理小鼠成骨细胞MC3T3-E1(克隆14)。然后分别在体积分数1%或21%氧张力下进行1-24 h的预处理。结果与结论:(1)缺氧诱导因子2α在成骨细胞缺氧中表达明显增高。而拉喹莫德可以抑制成骨细胞中缺氧诱导因子2α及其目标基因在小鼠成骨细胞(MC3T3-E1细胞)中的表达。(2)拉喹莫德以蛋白酶依赖、von Hippel-Lindau(VHL)蛋白不依赖的方式促进缺氧诱导因子2α的降解,可打断缺氧诱导因子2α和它的分子伴侣热休克蛋白90之间的相互作用,促进缺氧诱导因子2α和激活的蛋白酶C受体之间的相互作用。(3)结果显示拉喹莫德可能通过影响缺氧诱导因子2α蛋白的折叠和成熟从而促进其降解,可通过改变与伴侣蛋白热休克蛋白90和RACK1的功能性相互作用来抑制成骨细胞中的缺氧诱导因子2α。BACKGROUND： Fractures can induce bone cell hypoxia, and remarkably reduce the oxygen tension in cells. Hypoxia-inducible factor-2α is a key oxygen-dependent transcriptional activator to regulate the body function under hypoxia and mediate the release of various inflammatory factors after fractures. OBJECTIVE： To explore the role of Laquinimod in expression and function of hypoxia-inducible factor-2α in osteoblasts. METHODS： Mouse osteoblasts MC3T3-E1（clone 14） were pretreated with Laquinimod at various concentrations（10-100 μmol/L） before hypoxia in the presence or absence of specific proteasome inhibitors MG132 or N-acetyl-leucyl-leucyl-norleucine. Then, the media were pre-conditioned in 1% or 21% oxygen tension for 1 to 24 hours. RESULTS AND CONCLUSION： Under hypoxia, the expression of hypoxia-inducible factor-2α in osteoblasts was increased remarkably, and Laquinimod could inhibit the expression of hypoxia-inducible factor-2α and its target genes in mouse MC3T3-E1 cells. Mechanistically, Laquinimod promoted hypoxia-inducible factor-2α degradation in a proteasome-dependent but von Hippel-Lindau protein-independent manner. Importantly, we found that Laquinimod disrupted the interaction between hypoxia-inducible factor-2α and its chaperone heat shock protein 90, but promoted the interaction between hypoxia-inducible factor-2α and the receptor of activated protein kinase C. These findings suggest that Laquinimod may promote the degradation of hypoxia-inducible factor-2α by affecting its folding and maturation. Laquinimod is a novel inhibitor of hypoxia-inducible factor-2α by changing its functional interaction with chaperone proteins heat shock protein 90 and receptor of activated protein kinase C.

关 键 词：成骨细胞 缺氧 组织工程 组织构建 拉喹莫德 缺氧诱导因子2α 热休克蛋白90 活化的蛋白酶C(RACK1)受体 蛋白酶体降解 

分 类 号：R318[医药卫生—生物医学工程]