APOB48 downregulation is the causing factor in mediating iAs-induced lipid accumulation in enterocytes

APOB48 下调是介导 iAs 诱导的肠细胞脂质积累的原因

• 批准号: 10538854
• 负责人: Robert H Tukey
• 金额: $ 43.45万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-16 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10538854
• 关键词: Abetalipoproteinemia; Anabolism; Anderson syndrome; Apical; Apolipoproteins; Apolipoproteins B; Arsenic; Automobile Driving; Biochemical; Blood; Cell Differentiation process; Cell Maturation; Chylomicrons; Clinical; Cognitive; Complementary DNA; Coupled; DNA Sequence Alteration; Data; Development; Dietary Fats; Disease; Down-Regulation; Elements; Engineering; Enterocytes; Epithelial; Epithelial Cells; Essential Fatty Acids; Event; Exposure to; Fat-Soluble Vitamin; Fatty Acids; Fatty acid glycerol esters; Food; Foundations; Gastrointestinal tract structure; Gene Cluster; Gene Expression; Genes; Goals; Growth; Health; High Pressure Liquid Chromatography; Histologic; Human; Human Milk; Hypobetalipoproteinemia; Impairment; Individual; Ingestion; Intestinal Secretions; Intestines; Laboratories; Life; Link; Lipids; Longevity; Malnutrition; Mass Spectrum Analysis; Measures; Mediating; Mus; Neonatal; Oleic Acids; Oral; Oral Administration; Outcome; Oxidative Stress; Pathologic; Persons; Phenotype; Physiological; Plasma; Plasmids; Research; Resistance; Risk; Sampling; Side; Site; Small Intestines; Structure; Techniques; Testing; Tissues; Toxic effect; Transgenes; Transgenic Mice; Vacuole; Villus; Western Blotting; absorption; apolipoprotein B-48; attenuation; contaminated drinking water; crypt cell; dietary; early life exposure; epidemiology study; experimental study; fast protein liquid chromatography; fetal; functional outcomes; hypocholesterolemia; infancy; infection risk; intestinal epithelium; lipid metabolism; microscopic imaging; mortality; mouse model; neonatal mice; nutrition; overexpression; promoter; stem cell proliferation; suckling; villin

ABSTRACT Early life exposure to arsenic during fetal and neonatal development is a prerequisite to accelerated toxicity and delayed health consequences. Humans ingest arsenic through contaminated drinking water and foods with the intestinal tract being the primary site for arsenic absorption. With whole life exposure to arsenic occurring worldwide, there is limited data available on arsenic’s effects on the intestinal tract, especially during the early developmental stage. Our laboratory has demonstrated that oral arsenic treatment induces oxidative stress in the intestinal tissues, altering significant overall gene expression. Most recently, we observed that oral administration of inorganic arsenic (iAs) to neonatal mice dramatically accelerates intestinal stem cell (ISC) proliferation and intestinal epithelial cell (IEC) differentiation. Histological examination and biochemical analysis have revealed that iAs exposure leads to drastic lipid accumulation in intestinal enterocytes. When we treated neonatal mice with oleic acid, which is abundant in breast milk, this treatment mimics what we observed with iAs-induced pathophysiological changes in the small intestine. Thus, it is likely that lipid accumulation from iAs exposure mediates iAs-induced intestinal effects. As the functionality of the digestive tract is determined primarily by the small intestine, through altering the epithelium function, early life iAs exposure may generate a myriad of health challenges that could predispose individuals to a greater disease vulnerability. Therefore, understanding how iAs impacts on intestinal lipid metabolism will be the focus of our studies. We have identified that apolipoprotein B48 (APOB48), the structural component of chylomicron synthesis and secretion, is dramatically downregulated following iAs exposure. We will test the hypothesis that downregulated APOB48 is the causing factor in mediating iAs-induced lipid accumulation in enterocytes. In this proposal, we will determine the functional outcomes of APOB48 downregulation by measuring lipid content in plasma samples, including lipid profiling, levels of fat-soluble vitamins, and essential fatty acids. We will determine the fat absorption capability in mice following iAs exposure (Aim 1). We will also determine if overexpression of the constitutive active APOB48 in intestinal tissue counters iAs induced enterocyte lipid accumulation by conducting experiments in transgenic mice carrying a villin-promoter driven human APOB cDNA (Aim 2). We contend that these experiments will lay the foundation for an understanding of the underlying mechanisms leading to iAs induced intestinal lipid accumulation in neonatal mice, an event that we predict may predispose mice to accelerated physiological changes and diseases later in life.

摘要 生命早期在胎儿和新生儿发育期间暴露于砷是加速毒性的先决条件 并延缓了健康后果。人类通过受污染的饮用水和食物摄入砷 肠道是砷吸收的主要部位。终生接触砷 发生在世界各地，关于砷对肠道的影响的现有数据有限，特别是在 早期发育阶段。我们的实验室已经证明，口服砷治疗可以诱导 肠道组织中的氧化应激，改变了显著的整体基因表达。最近，我们 观察到，口服无机砷(IAS)显著加快了新生小鼠的速度 肠干细胞(ISC)增殖和肠上皮细胞(IEC)分化。组织学 检查和生化分析表明，暴露于IAS会导致大鼠体内脂质的急剧积聚 肠上皮细胞。当我们用母乳中丰富的油酸治疗新生小鼠时，这一点 治疗模拟了我们观察到的IAS诱导的小肠病理生理变化。因此， IAS暴露引起的脂质堆积很可能介导了IAS诱导的肠道效应。作为功能 消化道的功能主要由小肠决定，通过改变上皮功能， 早期接触IAS可能会产生无数的健康挑战，这些挑战可能使个人容易患上 疾病的脆弱性更大。因此，了解IAS对肠道脂质代谢的影响将 是我们研究的重点。我们已经鉴定出载脂蛋白B48(APOB48)，其结构是 乳胶粒合成和分泌的组成部分，在IAS暴露后显著下调。我们 将检验APOB48下调是调节IAS诱导的血脂的原因的假设 在肠道细胞中积聚。在本提案中，我们将确定APOB48的功能结果 通过测量血浆样本中的脂类含量来下调，包括脂谱、脂溶水平 维生素和必需脂肪酸。我们将测定IAS后小鼠的脂肪吸收能力 暴露(目标1)。我们还将确定结构性活性APOB48是否在肠道中过表达 转基因小鼠体内组织对抗IAS诱导的肠细胞脂质蓄积 携带由绒毛蛋白启动子驱动的人载脂蛋白B基因(AIM 2)。我们认为这些实验将 为了解IAS诱导肠脂代谢的潜在机制奠定基础 新生小鼠体内的蓄积，我们预测这一事件可能会使小鼠更容易出现生理性加速 在以后的生活中的变化和疾病。