Gut mucosal mast cells are activated by fat absorption: physiology and mechanism

脂肪吸收激活肠道粘膜肥大细胞：生理学和机制

• 批准号: 8242696
• 负责人: PATRICK TSO
• 金额: $ 34.15万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8242696
• 关键词: Acute; Address; Adverse effects; Affect; Anesthesia procedures; Animals; Atherosclerosis; Basophils; Blood; Blood Circulation; Caco-2 Cells; Carbohydrates; Cardiovascular Diseases; Cell Degranulation; Cell Line; Cells; Chronic; Chylomicrons; Clinical; Connective Tissue; Conscious; Consumption; Coronary heart disease; Diabetes Mellitus; Diet; Dietary Fats; Disease; Enterocytes; Enzymes; Epithelial Cells; Etiology; Exposure to; Fasting; Fatty Acids; Fatty acid glycerol esters; Fistula; Future; Gastrointestinal tract structure; Health; In Vitro; Inflammatory; Ingestion; Intestines; Knowledge; Lamina Propria; Linoleic Acids; Lipids; Lymph; Lymphatic; Mast Cell Stabilizer; Measures; Mediator of activation protein; Metabolic syndrome; Modeling; Modification; Monitor; NF-kappa B; NFKB Signaling Pathway; Obesity; Omega-3 Fatty Acids; Outcome; Patients; Peptide Hydrolases; Physiological; Physiology; Process; Production; Proteins; Rattus; Relative (related person); Role; Testing; Therapeutic; Time; Tissues; Tryptase; Work; absorption; arachidonate; chemokine; clinically relevant; cytokine; experience; feeding; gastrointestinal; gastrointestinal function; insight; interest; leukemia; lipid mediator; long chain fatty acid; mast cell; novel; nutrition; public health relevance; release factor; response; uptake

DESCRIPTION (provided by applicant): In patients with diabetes, obesity, or cardiovascular disease, the circulating proinflammatory mediators are often elevated. We made the novel observation that intestinal mucosal mast cells (MMC) are activated by fat absorption. In our well established conscious lymph fistula rats, we showed that fat absorption activates the intestinal mucosal mast cells (MMC) and they degranulate as evidenced by the marked increase (~ 20 fold) of the MMC marker protease II in intestinal lymph relative to fasting lymph (pre-ingestion of fat). This observation is very exciting from the standpoint of gut physiology; it may have profound clinical implications. We consume fat a few times a day and so the MMC are activated frequently during the day. With the activation and degranulation of MMC, the gut may be an important contributor to the circulating proinflammatory mediators. We hypothesized that the absorption of lipids and the formation and secretion of chylomicrons (CMs) activate the MMCs. This action is lipid specific and is not shared by proteins or carbohydrates. We further hypothesize that acute and chronic consumption of fat, the type of fat, influence its ability to activate the MMCs and that the order of potency is omega 6 (linoleate & arachidonate) > omega 9 (oleate) > omega 3 fatty acids (linolenate). To test these hypotheses, we proposed the following studies: Specific Aim 1. We will determine the relationship between intestinal fat absorption and MMC activation. Subaims: 1) to further characterize the activation of MMC by measuring the release of mast cell mediators in lymph and tissue during fat absorption, we will determine if the release of lipid mediators, cytokines, chemokines is mostly from MMC by using the mast cell deficient Ws/Ws rats; 2) to determine if the presence or absence of MMC stabilizers affects intestinal uptake and lymphatic transport of dietary lipids. We will also study fat absorption in Ws/Ws rats. Specific Aim 2. We hypothesize that the production of CMs, resulting from dietary polyunsaturated long-chain fatty acids (FA) linoleic acid (18:2, n-6) is a potent determinant of the mast cell activation and this action is differently affected by the type of fatty acids. We will determine the acute and chronic exposure to fatty acids with different degree of unsaturation and the type (n-3, n-6, and n-9) fatty acids on MMC activation by fat absorption. Specific Aim 3. We will test our hypothesis that fatty acid or the processing of CMs by the enterocytes results in the release of factor/factors that cause the activation of the MMCs (e.g. NF-kB response). To test our hypotheses, we have proposed the following 2 subaims. 1) We will study the in vitro effects of different types of FAs on rat basophil leukemia cells (RBL-2H3 cells, a surrogate of the rat MMC) activation through NF-kB signaling pathway; 2) We will study the interaction of chylous lymph and its components e.g. chylomicrons (CMs) or the media containing CMs by the intestinal epithelial cell line (Caco-2 cells) on RBC-2H3 cell NF-kB response. If the outcome is positive, we will isolate the factor/factors involved. PUBLIC HEALTH RELEVANCE: By focusing on the relationship between fat absorption and mucosal mast cell degranulation, our proposed studies will identify the role of gut-derived inflammatory factors in the normal process of dietary fat absorption and transport, identify which inflammatory agents are generated by normal fat absorption and may enter the general circulation, and contribute to the etiology of various diseases such as diabetes, metabolic syndrome, and atherosclerosis and coronary heart disease. Our results will also greatly enhance our understanding of function of gastrointestinal lymphatics in health and disease by clarifying the changes which occur in GI lymph parameters during normal physiological states such as fasting and lipid absorption, laying the ground work for future studies comparing the differences in lymph between diseased states and normal physiological states.

描述（由申请人提供）：在糖尿病、肥胖或心血管疾病患者中，循环促炎介质通常升高。我们发现肠粘膜肥大细胞（MMC）被脂肪吸收激活。在我们建立良好的清醒淋巴瘘大鼠中，我们发现脂肪吸收激活了肠粘膜肥大细胞（MMC），并通过肠淋巴中MMC标志物蛋白酶II相对于禁食淋巴（摄入脂肪前）的显著增加（约20倍）证明了它们的去增殖。从肠道生理学的角度来看，这一观察结果非常令人兴奋;它可能具有深远的临床意义。我们每天消耗脂肪几次，所以MMC在白天经常被激活。随着MMC的活化和脱颗粒，肠道可能是循环促炎介质的重要贡献者。我们推测，脂质的吸收和乳糜微粒（CMs）的形成和分泌激活MMC。这种作用是脂质特异性的，不被蛋白质或碳水化合物共享。我们进一步假设，脂肪的急性和慢性消耗，脂肪的类型，影响其激活MMCs的能力，并且效力的顺序是omega 6（亚油酸酯和花生四烯酸酯）> omega 9（油酸酯）> omega 3脂肪酸（亚麻酸酯）。为了验证这些假设，我们提出了以下研究：具体目标1。我们将确定肠道脂肪吸收和MMC激活之间的关系。次级方案：1）通过测量脂肪吸收过程中淋巴和组织中肥大细胞介质的释放来进一步表征MMC的活化，我们将通过使用肥大细胞缺陷的Ws/Ws大鼠来确定脂质介质、细胞因子、趋化因子的释放是否主要来自MMC; 2）确定MMC稳定剂的存在或不存在是否影响膳食脂质的肠摄取和淋巴转运。我们还将研究Ws/Ws大鼠的脂肪吸收。具体目标2。我们假设，由膳食多不饱和长链脂肪酸（FA）亚油酸（18：2，n-6）产生的CM的产生是肥大细胞活化的有效决定因素，并且这种作用受到脂肪酸类型的不同影响。我们将确定急性和慢性暴露于不同程度的不饱和脂肪酸和类型（n-3，n-6和n-9）脂肪酸对MMC激活脂肪吸收。具体目标3。我们将检验我们的假设，即脂肪酸或肠上皮细胞对CM的加工导致释放引起MMC激活的因子（例如NF-κ B反应）。为了验证我们的假设，我们提出了以下两个子目标。1)我们将研究不同类型的FA通过NF-kB信号通路对大鼠嗜碱性白血病细胞（RBL-2 H3细胞，大鼠MMC的替代细胞）激活的体外影响; 2）我们将研究乳糜淋巴及其成分（例如乳糜微粒（CMs））或含有CMs的培养基通过肠上皮细胞系（Caco-2细胞）对RBC-2 H3细胞NF-kB反应的相互作用。如果结果是肯定的，我们将隔离所涉及的因素。 公共卫生关系：通过关注脂肪吸收和粘膜肥大细胞脱颗粒之间的关系，我们提出的研究将确定肠源性炎症因子在膳食脂肪吸收和转运的正常过程中的作用，确定哪些炎症因子由正常脂肪吸收产生并可能进入全身循环，并有助于各种疾病的病因，如糖尿病，代谢综合征，动脉粥样硬化和冠心病。我们的研究结果也将大大提高我们对健康和疾病的胃肠道淋巴功能的理解，通过阐明胃肠道淋巴参数在正常生理状态下发生的变化，如禁食和脂质吸收，为未来的研究奠定了基础，比较淋巴在疾病状态和正常生理状态之间的差异。