Targeting the Enterocyte to Prevent Vascular Inflammation

摘要 西方饮食(WD)喂养低密度脂蛋白受体缺失(LDLR-/-)小鼠不仅引起血脂异常 和动脉粥样硬化，它还会引起大脑、肾脏和小肠系膜的血管炎症。 肠道比身体其他任何器官都含有更多的免疫细胞。的数量和激活状态 这些免疫细胞在一定程度上是由细菌和病毒产物通过肠道细胞控制的，但它们是 也受脂类信号分子控制，如溶血磷脂酸18：1(LPA 18：1)。一位少校 LPA 18：1的前体是溶血磷脂酰胆碱18：1(LysoPC 18：1)。肠道细胞中形成LysoPC 18：1 优先使用硬脂酰辅酶A去饱和酶-1(SCD1)在肠细胞中合成的油酸。肠上皮细胞 在肠细胞溶血磷脂酶D(自体趋化)的作用下，LysoPC 18：1转化为LPA 18：1。膳食脂肪 通过双重控制的信号通路改变微生物群并增加肠道通透性 细菌脂多糖(LPS)和肠细胞产生的脂信号分子(如LPA)的水平 我们假设，小肠中的内毒素水平和LPA 18：1等分子决定了 对饮食脂肪挑战的全身反应。目标1将确定肠细胞的作用和机制(S) SCD1在饮食诱导的血脂异常和血管炎症中的作用。向Ldlr-/-实施LPA 18：1或LysoPC 18：1 喂食食物的小鼠模拟喂食这些小鼠WD。我们产生了肠细胞敲除的Ldlr-/-小鼠 在WD上降低肠细胞LysoPC 18：1和LPA 18：1的水平。我们将确定肠细胞 抑制SCD1有利于改变：1)动脉粥样硬化；2)胆固醇和脂肪吸收；3) 微生物组的组成；4)微生物组-宿主的相互作用；5)肠道通透性和血清内毒素 水平；6)肠细胞分泌的脂类(用脂质组学方法测定)；以及7)Notch途径 改善饮食引起的血管炎症。目标2将确定肠细胞的作用和机制(S) 溶血磷脂酶D(自体趋化)。我们用肠细胞敲除Enpp2基因产生了Ldlr-/-小鼠，Enpp2基因是 自体分类素。肠细胞敲除Enpp2可降低肠上皮细胞和血浆中LPA18：1的水平； 降低WD引起的血脂异常和全身炎症。我们将确定肠细胞基因敲除是否 Enpp2可减少动脉粥样硬化。我们假设肠细胞不饱和LPA水平的增加 LPA 18：1等物种会导致肠道细胞分泌的乳糜粒被氧化，从而导致 血管发炎。我们将确定肠细胞敲除Enpp2是否有利于改变这些事件。目标 3将确定表达载脂蛋白A-I模拟物的番茄浓缩物的作用机制(S) 转基因多肽6F(Tg6F)改善饮食诱导的血脂异常和血管炎症。我们 将确定Tg6F是否模仿肠细胞敲除SCD1和Enpp2。我们会确定去掉的脂类 用Tg6F从小鼠空肠中取出。我们将确定Tg6F是否保留了Notch途径并阻止了血管 饲料中添加LysoPC 18：1、LPA 18：1或WD的小鼠的炎症反应。

Abstract Feeding low density lipoprotein receptor null (Ldlr-/-) mice a Western Diet (WD) not only causes dyslipidemia and atherosclerosis, it also causes vascular inflammation of brain, kidneys, and the small intestine mesentery. The intestine contains more immune cells than any other organ in the body. The number and activation state of these immune cells is in part governed by bacterial and viral products that get past the enterocytes, but they are also governed by lipid signaling molecules such as lysophosphatidic acid 18:1 (LPA 18:1). A major precursor to LPA 18:1 is lysophosphatidylcholine 18:1 (LysoPC 18:1). LysoPC 18:1 is formed in enterocytes preferentially using oleic acid synthesized in the enterocytes by Stearoyl Co-A desaturase-1 (Scd1). Enterocyte LysoPC 18:1 is converted to LPA 18:1 by the action of enterocyte lysophospholipase D (autotaxin). Dietary fat alters the microbiome and increases intestinal permeability via signaling pathways dually controlled by the levels of bacterial lipopolysaccharide (LPS), and enterocyte generated lipid signaling molecules such as LPA 18:1. We hypothesize that the levels of LPS and molecules such as LPA 18:1 in the small intestine determine the systemic response to dietary fat challenge. Aim 1 will determine the role and mechanism(s) of enterocyte Scd1 in diet-induced dyslipidemia and vascular inflammation. Administering LPA 18:1 or LysoPC 18:1 to Ldlr-/- mice on a chow diet mimicked feeding these mice WD. We generated Ldlr-/- mice with enterocyte knockdown of Scd1, which on WD lowered enterocyte levels of LysoPC 18:1 and LPA 18:1. We will determine if enterocyte knockdown of Scd1 favorably alters: 1) aortic atherosclerosis; 2) cholesterol and lipid absorption; 3) composition of the microbiome; 4) microbiome-host interactions; 5) intestinal permeability and serum endotoxin levels; 6) lipids secreted from enterocytes (determined using a lipidomics approach); and 7) Notch pathway to ameliorate diet-induced vascular inflammation. Aim 2 will determine the role and mechanism(s) of enterocyte lysophospholipase D (autotaxin). We generated Ldlr-/- mice with enterocyte knockdown of Enpp2, the gene for autotaxin. Enterocyte knockdown of Enpp2 reduced levels of LPA 18:1 in enterocytes and plasma, and decreased WD-induced dyslipidemia and systemic inflammation. We will determine if enterocyte knockdown of Enpp2 reduces aortic atherosclerosis. We hypothesize that increased levels of enterocyte unsaturated LPA species such as LPA 18:1 lead to the oxidation of chylomicrons secreted from enterocytes, which leads to vascular inflammation. We will determine if enterocyte knockdown of Enpp2 favorably alters these events. Aim 3 will determine the mechanism(s) of action of a concentrate of tomatoes expressing the apoA-I mimetic peptide 6F from a transgene (Tg6F) in ameliorating diet-induced dyslipidemia and vascular inflammation. We will determine if Tg6F mimics enterocyte knockdown of Scd1 and Enpp2. We will determine the lipids removed from mouse jejunum by Tg6F. We will determine if Tg6F preserves the Notch pathway and prevents vascular inflammation in mice fed chow supplemented with LysoPC 18:1, or LPA 18:1 or fed WD.