摘要
目的 研究apelin及其受体APJ在人成骨细胞的表达和apelin对成骨细胞的作用。方法 RT-PCR和Western印迹法检测apelin和APJ在人成骨细胞的表达。用apelin处理人成骨细胞，^3H掺入法（^3H-TdR）和细胞计数法测定细胞的增殖，通过测定细胞内碱性磷酸酶（ALP）活性、骨钙素分泌水平和Ⅰ型胶原的生成来分析细胞功能。Western印迹法检测信号通路的激活。通过小分子干扰核糖核酸（siRNA）技术阻断APJ，观察其对细胞增殖和信号通路的影响。结果Apelin和APJ在人成骨细胞均有表达，Apelin能促进人成骨细胞增殖，但对其ALP活性、骨钙素的分泌和Ⅰ型胶原的生成无影响。通过siRNA技术阻断APJ能消除apelin对细胞增殖的促进作用。Apelin能诱导人成骨细胞磷脂酰肌醇3激酶（P13K）下游底物蛋白激酶B（Akt）的活化，但不能诱导c-junN一端激酶（JNK）、p38和细胞外信号调节激酶1／2（ERK1／2）等丝裂原活化蛋白激酶（MAPK）的活化。siRNA干扰APJ对Akt的活化起抑制作用。P13K抑制剂（LY294002）能消除apelin对细胞增殖的促进作用和Akt的活化。结论 人成骨细胞表达apelin和APJ，Apelin通过APJ／P13K／Akt途径促进人成骨细胞增殖，但对其分化无影响。
Objective To observe apelin and its receptor （APJ） expressions in human osteoblasts and evaluate the effect of apelin on osteoblasts. Methods The expressions of apelin and APJ in human osteoblasts were tested by RT-PCR and Western blot. After human osteoblasts were treated with apelin, cell proliferation was measured by [ ^3H] thymidine incorporation and cell counting. Cell function was measured by alkaline phosphatase （ALP） activity, the secreted osteocalcin level and type Ⅰ collagen production . The activation of signaling cascades was tested by Western blot. Small-interfering RNA （siRNA） to blockade APJ was applied to observe effects of apelin on cell proliferation and the activation of signaling cascades. Results Both apelin and APJ were expressed in human osteoblasts. Apelin increased the proliferation and did not show the influences on ALP activity, osteocalcin secretion and type Ⅰ collagen production in human osteoblasts. Apelin induced activation of phosphatidylinositol-3 kinase （PI3K） downstream effector （Akt）, but not mitogen-activated protein kinase （MAPK） such as c-jun N-terminal kinase （JNK） , p38 and ERK1/2 in human osteoblasts. Suppression of APJ with siRNA or LY294002 （ PI3 K inhibitor） abolished the apelin-induced cell proliferation and the activation of Akt. Conclusion Human osteoblasts express apelin and APJ. Apelin stimulates the proliferation of human osteoblast via APJ/PI3K/Akt pathway, but has no effect on osteoblast differentiation.
出处
《中华内分泌代谢杂志》
CAS
CSCD
北大核心
2007年第3期211-215,共5页
Chinese Journal of Endocrinology and Metabolism
基金
国家自然科学基金(30200322
30400218)
湖南省杰出青年基金(03JJY1005)
