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.

抽象的 胎儿和新生儿发育期间砷的早期寿命暴露是加速毒性的先决条件 并延迟健康后果。人类通过污染的饮用水和食物摄入砷 肠道是砷滥用的主要部位。随着砷的整体暴露 发生在全球范围内，有限的数据可用，砷对肠道的影响，尤其是在 早期发展阶段。我们的实验室表明，口服砷治疗会诱导 肠道组织中的氧化应激，改变了显着的总体基因表达。最近，我们 观察到对新生小鼠的口服无机砷（IAS）急剧加速 肠道干细胞（ISC）增殖和肠上皮细胞（IEC）分化。组织学 检查和生化分析表明，IAS暴露会导致脂质的大量积累 肠肠上皮细胞。当我们用在母乳中丰富的油酸治疗新生儿小鼠时， 治疗模仿了我们观察到的小肠中IAS诱导的病理生理变化。那， IAS暴露的脂质积累可能介导了IAS诱导的肠道作用。作为功​​能 消化道的主要由小肠决定，通过改变上皮功能， 早期生活IAS暴露可能会引起无数的健康挑战 更大的疾病脆弱性。因此，了解IAS如何影响肠道脂质代谢 成为我们研究的重点。我们已经确定载脂蛋白B48（APOB48），结构性 IAS暴露后，乳糜微粒合成和分泌的成分显着下调。我们 将检验以下假设：下调的APOB48是介导IAS诱导脂质的导致因子 在肠细胞中积聚。在此提案中，我们将确定APOB48的功能结果 通过测量血浆样品中的脂质含量的下调，包括脂质分析，脂溶性水平 维生素和必需脂肪酸。我们将在IAS之后确定小鼠的脂肪吸收能力 曝光（目标1）。我们还将确定肠内构型活性APOB48的过表达是否 组织计数IAS通过在转基因小鼠中进行实验来诱导肠细胞脂质的积累 携带Villin启动器驱动的人Apob cDNA（AIM 2）。我们认为这些实验将 为理解导致IAS引起肠道脂质的基础机制奠定基础 新生儿小鼠的积累，我们预测的事件可能会使小鼠易于加速生理 生活后期的变化和疾病。