LCAT-KNOCKOUT MICE--NEW ANIMAL MODEL FOR HUMAN LCAT DEFICIENCY

卵磷脂胆固醇酰基转移酶(LCAT)，是 酯化存在于血浆脂蛋白中的胆固醇，发挥着中枢作用 在高密度脂蛋白代谢中的作用。LCAT缺乏的患者可能会出现 角膜混浊和肾脏疾病以及血浆高密度脂蛋白-C和 载脂蛋白A-I浓度和甘油三酯增加。评估角色的步骤 LCAT在胆固醇逆向转运和糖尿病的发生发展中的作用 我们已经为人类建立了一个动脉粥样硬化的小鼠模型 对LCAT基因进行靶向阻断导致LCAT缺乏症 小鼠胚胎干细胞。纯合子LCAT缺陷小鼠存活并健康 在出生的时候。年龄匹配的对照组同胞的血浆LCAT活性(n=38， LCAT ACT=42+/-5nmol/h/ml)降至-lt；0.7nmol/h/ml 纯合子。与对照组相比，纯合子LCAT缺陷小鼠 降低胆固醇(28%)、胆固醇酯(14%)、磷脂 (46%)、高密度脂蛋白(3%)和载脂蛋白A-I(17%)。血浆的分析 FPLC检测LCAT基因缺陷纯合子小鼠脂蛋白 随着较小尺寸的存在，高密度脂蛋白-胆固醇显著降低 颗粒，以及富含甘油三酯的IDL/LDL。作为对高水平的反应 脂肪，高胆固醇饮食，纯合子LCAT-Ko小鼠(n=9)(以mg/dl为单位) 胆固醇32+/-13，甘油三酯185+/-129，胆固醇酯10+/-9， 高密度脂蛋白-C 7+/-6和载脂蛋白A-I 27+/-24(25%、167%、15%、9%和11%； 对照；p&lt；0.05)。电子显微镜显示存在 高密度脂蛋白新生盘(d=1.063-1.25)。主动脉粥样硬化的临床分析 揭示了杂合子和纯合子LCAT-Ko的趋势(ns；p&gt；0.05) 与对照组相比。肾脏的组织学和EM分析显示 ALL纯合子肾小球系膜细胞增殖与肾小球硬化 LCAT-KO小鼠。未见明显的角膜混浊。可提供的 人类LCAT缺乏症的纯合子动物模型将有助于我们 对LCAT在肾脏发育中作用的认识 疾病和动脉粥样硬化。

Lecithin cholesterol acyltransferase (LCAT), the major enzyme which esterifies cholesterol present in plasma lipoproteins, plays a central role in HDL metabolism. Patients with LCAT deficiency may present with corneal opacities and renal disease as well as reduced plasma HDL-C and apoA-I concentrations and increased triglycerides. To evaluate the role that LCAT plays in reverse cholesterol transport and the development of atherosclerosis we have established a mouse model for human LCAT-deficiency by performing targeted disruption of the LCAT gene in mouse ES cells. Homozygous LCAT-deficient mice were viable and healthy at birth. Plasma LCAT activity in age-matched control siblings (n=38, LCAT act=42+/-5 nmol/h/ml) was decreased to <0.7 nmol/h/ml in homozygotes. Compared to control mice, homozygous LCAT-deficient mice had decreased cholesterol (28%), cholesteryl ester (14%), phospholipids (46%), HDL-cholesterol (3%) and apoA-I (17%). Analysis of plasma lipoproteins in homozygous LCAT-deficient mice by FPLC demonstrated severe reduction in HDL-cholesterol with the presence of smaller sized particles, as well as triglyceride-rich IDL/LDL. In response to a high fat, high cholesterol diet, homozygous LCAT-ko mice (n=9) had (in mg/dl) cholesterol 32+/-13, triglycerides 185+/-129, cholesteryl esters 10+/-9, HDL-C 7+/-6 and apoA-I 27+/-24 (25%, 167%, 15%, 9% and 11%; that of controls;p<0.05). Electron microscopy (EM) demonstrated the presence of nascent discs in HDL (d=1.063-1.25). Analysis of aortic atherosclerosis revealed a trend (ns;p>0.05)in heterozygous and homozygous LCAT-ko compared to controls. Histologic and EM analysis of kidneys revealed mesangial cell proliferation and glomerulosclerosis in all homozygous LCAT-ko mice. No corneal opacities were evident. The availability of a homozygous animal model for human LCAT deficiency will facilitate our understanding of the role that LCAT plays in the development of renal disease and atherosclerosis.