低密度脂蛋白受体敲除对小鼠系统代谢的影响规律研究

发布时间：2018-06-20 11:57

本文选题：低密度脂蛋白受体敲除 + 西式饮食　；参考：《中国科学院研究生院(武汉物理与数学研究所)》2015年博士论文

【摘要】：本论文围绕低密度脂蛋白(LDL)受体敲除研究其对小鼠系统代谢的影响规律。脂类代谢相关受体或蛋白表达异常(LDL受体或apoE敲除)、高脂高胆固醇饮食等因素引起动脉粥样硬化最终导致各类心血管疾病。我们通过核磁共振和气相色谱-氢离子火焰检测器/质谱技术等代谢组学的常用分析手段,结合临床血生化、病理切片以及分子生物学等实验技术(非代谢组的部分均由北京大学医学部李丹博士完成)等,使用LDL受体敲除(LDLR-/-')小鼠模型多系统研究动脉粥样硬化的发病机理和病程进展。我们发现当给予LDLR-/-小鼠连续12周的高脂高胆固醇高胆盐饮食(简称为西式饮食)会引起明显的动脉斑块、炎性细胞浸润和胶原水平的升高,同时伴随动脉和肝脏中的炎性因子表达增加。西式饮食同样会涉及多条代谢通路被干扰,伴随多器官代谢组改变包括体液(血浆、尿液)和组织(肝脏、心脏和肾脏)。具体包括胆固醇稳态的破坏、氨基酸和蛋白质的合成受干扰、肠道菌群功能的改变,同时伴随维生素B3、胆碱、嘌呤和嘧啶的代谢改变。西式饮食会引起硬脂酸辅酶A去饱和酶1降低,尿液中尿囊素增加和肝脏多不饱和脂肪酸与单不饱和脂肪酸比例出现降低,由此可推断氧化应激增加。当转换成正常饮食后,由动脉粥样硬化引起的代谢组改变大多逐渐恢复到正常水平,而动脉斑块、炎症因子水平、胶原含量等仅部分减轻。这些发现为我们提供了饮食导致动脉粥样硬化模型的重要的分子生物学依据,也说明结合代谢组研究动脉粥样硬化的多系统改变对于研究其分子机制是非常有效的。动脉粥样硬化治疗中常规使用非甾体类抗炎药,这类药是通过抑制花生四烯酸途径中的环氧酶从而使下游的前列腺素类物质合成减少从而抗炎,但前列腺素类在全身表达,发挥重要的生理功能,当合成减少时,会出现严重副作用,我们考虑当选择性拮抗某一种前列腺素受体,会产生哪些代谢应答?我们探讨了花生四烯酸下游的环氧酶途径中的前列腺素E2受体亚型1作为研究对象。选择性拮抗EPl引起小鼠体内脂类分解增加、胆固醇代谢受到干扰、核苷酸从头合成途径增强、糖异生和三羧酸循环受抑制以及氨基酸代谢异常等,但由于模型质量整体不是很高,使用的均是多重单变量结果,说明该药物毒性并不强,在生物体内较为安全,为研究EP1生理功能及EP1拮抗剂的临床前评估提供了丰富的代谢组基础数据。另外,结合固相萃取、液相色谱技术以及一维(一维氢谱、一维磷谱)、二维核磁共振波谱(二维氢碳相关谱、二维磷氢相关谱)的实验数据和相关文献报道,我们在小鼠肾脏水相提取物中发现并归属出酪氨酸-4-0-β-葡萄糖醛酸这个代谢物。
[Abstract]:The effects of low density lipoprotein (LDL) receptor knockout on systemic metabolism in mice were studied. Abnormal expression of lipid metabolism-related receptors or proteins; LDL receptors or apoE knockout; hyperlipidemia and cholesterol diet lead to atherosclerosis leading to various cardiovascular diseases. We combine clinical blood biochemistry with nuclear magnetic resonance (NMR) and gas chromatography-hydrogen ion flame detector / mass spectrometry. Pathological sections and molecular biology were used to study the pathogenesis and progression of atherosclerosis in the mouse model using LDL receptor knockout LDLR-R-(or LDLR-R) model, which was performed by Dr. Li Dan, Department of Medicine, Peking University, and so on. We found that when LDLR-r-mice were given a high-fat, high-cholesterol, high-bile salt diet for 12 weeks, it caused significant arterial plaque, inflammatory cell infiltration, and increased collagen levels. It was accompanied by increased expression of inflammatory factors in the arteries and liver. Western diets also involve interference with multiple metabolic pathways, accompanied by changes in body fluid (plasma, urine) and tissue (liver, heart, and kidney). These include disruption of cholesterol homeostasis, interference in the synthesis of amino acids and proteins, changes in intestinal flora function, and metabolic changes in vitamin B3, choline, purine and pyrimidine. Western diet could decrease stearic acid CoA desaturase 1, increase allantoin in urine and decrease the ratio of liver polyunsaturated fatty acids to monounsaturated fatty acids, which suggested that oxidative stress increased. When converted to a normal diet, the changes caused by atherosclerosis in the metabolic group gradually returned to normal level, while the arterial plaque, inflammatory factor level, collagen content were only partially reduced. These findings provide us with an important molecular biological basis for diet-induced atherosclerotic models, and suggest that the study of multisystem changes in atherosclerosis in combination with metabolic groups is very effective in studying its molecular mechanisms. Nonsteroidal anti-inflammatory drugs are routinely used in atherosclerosis therapy by inhibiting cyclooxygenase in the arachidonic acid pathway, which reduces the synthesis of downstream prostaglandins, but they are expressed throughout the body. Play an important physiological function, when synthesis decreases, there will be serious side effects, we consider when selectively antagonizing a certain prostaglandin receptor, what metabolic response? We studied prostaglandin E 2 receptor subtype 1 in the cyclooxygenase pathway downstream of arachidonic acid. Selective antagonism of EPL induced increased lipid catabolism, increased cholesterol metabolism, increased ab initio synthesis of nucleotides, inhibition of glycosomal and tricarboxylic acid cycles, and abnormal metabolism of amino acids, etc. However, because the quality of the model is not very high, the results of multiple single variables are used, which indicates that the drug is not very toxic and is relatively safe in organisms. It provides abundant basic data for the study of physiological function of EP1 and preclinical evaluation of EP1 antagonist. In addition, in combination with solid phase extraction, liquid chromatography and experimental data of one-dimensional (one-dimensional hydrogen spectrum, one-dimensional phosphorus spectrum), two-dimensional nuclear magnetic resonance spectroscopy (two-dimensional hydrogen-carbon correlation spectrum, two-dimensional phosphorus-hydrogen correlation spectrum) and related literature reports, A metabolite of tyrosine-4-0-尾-glucuronic acid was found and identified in mouse kidney aqueous extract.
【学位授予单位】：中国科学院研究生院(武汉物理与数学研究所)
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R54

【相似文献】