Targeting the Enterocyte to Prevent Vascular Inflammation

摘要 用西方饮食（WD）喂养低密度脂蛋白受体缺失（Ldlr-/-）小鼠不仅会导致血脂异常， 和动脉粥样硬化，它还引起脑、肾和小肠肠系膜的血管炎症。 肠道含有比身体任何其他器官更多的免疫细胞。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的产物控制的，这些产物可以通过肠上皮细胞， 也由脂质信号分子如溶血磷脂酸18：1（LPA 18：1）控制。一个主要 LPA 18：1的前体是溶血磷脂酰胆碱18：1（LysoPC 18：1）。LysoPC 18：1在肠上皮细胞中形成 优先使用在肠细胞中由硬脂酰辅酶A去饱和酶-1（Scd 1）合成的油酸。肠细胞 LysoPC 18：1通过肠细胞溶血磷脂酶D（自分泌运动因子）的作用转化为LPA 18：1。膳食脂肪 改变微生物组，并通过双重控制的信号通路增加肠道通透性。 细菌脂多糖（LPS）和肠细胞产生的脂质信号分子（如LPA）水平 十八比一我们推测，小肠中LPS和LPA 18：1等分子的水平决定了 对膳食脂肪挑战的全身反应。目的1明确肠上皮细胞的作用和机制 膳食诱导的血脂异常和血管炎症中的scd 1。将LPA 18：1或LysoPC 18：1给予Ldlr-/- 喂食饲料的小鼠模仿喂食WD。我们用肠上皮细胞敲低产生了Ldlr-/-小鼠， 的Scd 1，这对WD降低肠细胞水平的LysoPC 18：1和LPA 18：1。我们将确定肠上皮细胞 Scd 1的敲除有利地改变：1）主动脉粥样硬化; 2）胆固醇和脂质吸收; 3） 微生物组的组成; 4）微生物组-宿主相互作用; 5）肠通透性和血清内毒素 水平; 6）从肠上皮细胞分泌的脂质（使用脂质组学方法测定）;和7）Notch途径， 改善饮食引起的血管炎症。目的2：明确肠上皮细胞在肿瘤发生发展中的作用及机制 溶血磷脂酶D（自分泌运动因子）。我们产生了Ldlr-/-小鼠，其肠上皮细胞敲低了Enpp 2， 自分泌运动因子Enpp 2的肠细胞敲低降低了肠细胞和血浆中LPA 18：1的水平， 降低WD诱导的血脂异常和全身炎症。我们将确定肠上皮细胞敲除 Enpp 2减少主动脉粥样硬化。我们假设肠上皮细胞不饱和LPA水平的增加 例如LPA 18：1的种类导致肠细胞分泌的乳糜微粒氧化，这导致 血管炎症我们将确定肠上皮细胞敲除Enpp 2是否有利地改变这些事件。目的 3将确定表达apoA-I模拟物的番茄浓缩物的作用机制 来自转基因的肽6 F（Tg 6 F）在改善饮食诱导的血脂异常和血管炎症中的作用。我们 将确定Tg 6 F是否模拟Scd 1和Enpp 2的肠细胞敲低。我们将确定去除的脂质 小鼠空肠Tg 6 F。我们将确定Tg 6 F是否保留了Notch通路，并阻止血管生成。 在喂食补充有LysoPC 18：1或LPA 18：1的食物或喂食WD的小鼠中，

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.