The Role of Tie1 in Gut and Mesenteric Lymphatic Function

Tie1 在肠道和肠系膜淋巴功能中的作用

• 批准号: 10045453
• 负责人: H Scott Baldwin
• 金额: $ 46.7万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-15 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10045453
• 关键词: Adipocytes; Adult; Animals; Area; Ascites; Birth; Body Composition; Body Weight; CRISPR/Cas technology; Carrier Proteins; Cells; Cholesterol; Data; Development; Diet; Dyslipidemias; Embryo; Endothelium; Exposure to; Fat-Soluble Vitamin; Functional disorder; Gene Expression Profile; Genes; Genetic Transcription; Glucose; Goals; High Fat Diet; Homeostasis; Hormones; Immunologic Surveillance; Individual; Inflammation; Inflammatory; Insulin; Intestines; Investigation; Laboratories; Leptin; Ligands; Lipids; Liquid substance; Lymph; Lymphatic; Lymphatic Abnormalities; Lymphatic Endothelial Cells; Lymphatic System; Lymphedema; Maintenance; Malnutrition; Measures; Mediating; Mesentery; Metabolic; Metabolic Diseases; Missense Mutation; Modeling; Morphology; Mus; Nutrient; Obesity; Pathologic Processes; Pathology; Phenotype; Play; Population; Prevention; Process; Protein-Losing Enteropathies; Receptor Protein-Tyrosine Kinases; Regulation; Role; Signal Pathway; Signal Transduction; Structure; TIE gene; Tamoxifen; Therapeutic Intervention; Thymidine Kinase; Tissues; Vascular Endothelial Cell; Weight Gain; absorption; adiponectin; attenuation; base; gastrointestinal; gastrointestinal system; in utero; in vivo; insight; juvenile animal; lipid transport; long chain fatty acid; lymph flow; lymphatic vasculature; mature animal; mouse model; mutant; new therapeutic target; novel; nutrient absorption; postnatal period; prenatal; receptor; single-cell RNA sequencing; uptake

PROJECT SUMMARY The lymphatic system is critical for tissue fluid homeostasis, lipid absorption, and immune surveillance and is no longer considered a “passive bystander” in pathological processes. The digestive lymphatic system, includ- ing intestinal and mesenteric lymphatics, plays a critical role in several pathological processes including obe- sity, metabolic disease, and dyslipidemia in addition to lymphedema and inflammation.3,4 While prenatal lym- phatic development has been an area of intensive investigation, insights into factors involved in post-natal reg- ulation of lymphatic maturation, remodeling, and maintenance of lymphatic structure and function is limited. Our laboratory has recently shown that the receptor tyrosine kinase TIE1 is required for lymphatic remodeling and normal lymphatic function in utero, and that deletion of Tie1 specifically from the developing lymphatic vas- culature prior to birth results in abnormal LV formation. We present new preliminary data that deletion of Tie1 in the early post-natal period results in malnutrition with poor weight gain, abnormal LV maturation, and asci- tes. In contrast, we show that Tie1 deletion in the adult animal results in severe LV dysfunction and profound diet-induced obesity (DIO) when challenged with a high fat diet (HFD). We hypothesize that TIE1 cell auton- omous and non-cell autonomous signaling plays a unique role in orchestrating early post-natal LV and lacteal maturation and function, and that TIE1 signaling is essential for maintenance of LV and lacteal structure and function in the mature animal. Therefore, we propose to: 1) Delineate the specific role of TIE1 signaling in early post-natal lacteal and LV maturation, and nutrient absorption, in vivo. Tie1fl/fl mice and an inducible LEC Cre line, Prox1CreERT, will be used to produce LEC-specific, temporal deletion of Tie1 (Tie1lecKO) in post-natal lymphatics. Quantitative and functional analyses will be used to characterize the unique phenotypes that result from TIE1 attenuation in intestinal lacteals and mesenteric LVs. 2) Determine the role of TIE1 in maintenance of lymphatic function in the adult and characterize its role in mediating DIO. Tie1lecKO and control (Tie1fl/fl) adult mice will be place on a 60% HFD or normal chow for 6 weeks following exposure to Tamoxifen. LV structure and function will be measured as well as alterations in body weight and composition, levels of circulating hormones insulin, leptin and adiponectin, sensitivity to glucose and insulin, and adipocyte morphology and inflammatory status. 3) Define the mechanisms of TIE1-mediated signaling required for LV and lacteal remodeling and maintenance, in vivo. Utilizing CRISPR/Cas9, we have devel- oped mice with missense mutations in critical intracellular domains of Tie1. Unique domain-specific effects on LV and lacteal structure and function will be characterized in the early post-natal and adult animals during the dynamic reorganization and maintenance processes, respectively. scRNA-seq and sc-UniFrac analysis will be employed to define TIE1-dependent signaling required for cell autonomous and non-autonomous LEC subtype transcriptional signatures regulating maturation and maintenance of the GI lymphatic system after birth.

项目概要 淋巴系统对于组织液稳态、脂质吸收和免疫监视至关重要，并且 不再被视为病理过程中的“被动旁观者”。消化淋巴系统，包括- 肠道和肠系膜淋巴管，在包括肥胖在内的多种病理过程中发挥着关键作用 除了淋巴水肿和炎症外，还有肥胖、代谢性疾病和血脂异常。3,4 饮食发育一直是一个深入研究的领域，深入了解产后调节所涉及的因素 淋巴管的成熟、重塑以及淋巴管结构和功能的维持是有限的。 我们的实验室最近表明受体酪氨酸激酶TIE1是淋巴重塑所必需的 和子宫内正常的淋巴功能，以及专门从发育中的淋巴管中删除 Tie1 出生前的培养会导致左心室形成异常。我们提供新的初步数据，即删除 Tie1 产后早期会导致营养不良，体重增加缓慢，左心室成熟异常，以及腹水。 测试。相比之下，我们发现成年动物中 Tie1 缺失会导致严重的左心室功能障碍和严重的左心室功能障碍。 当受到高脂肪饮食（HFD）挑战时，饮食诱发的肥胖（DIO）。我们假设 TIE1 细胞自主 细胞和非细胞自主信号在协调产后早期 LV 和 乳汁成熟和功能，TIE1 信号传导对于维持 LV 和乳汁至关重要 成熟动物的结构和功能。因此，我们建议： 1）划定具体角色 TIE1 信号在出生后早期乳汁和左心室成熟以及体内营养吸收中的作用。并列1fl/fl 小鼠和诱导型 LEC Cre 系 Prox1CreERT 将用于产生 LEC 特异性、暂时性缺失 产后淋巴管中的 Tie1 (Tie1lecKO)。定量和功能分析将用于表征 肠乳糜和肠系膜 LV 中 TIE1 减弱导致的独特表型。 2）确定 TIE1 在维持成人淋巴功能中的作用并表征其在介导中的作用 迪奥。 Tie1lecKO 和对照 (Tie1fl/fl) 成年小鼠将在 6 周内接受 60% HFD 或正常饮食 接触他莫昔芬。将测量左室结构和功能以及体重和体重的变化 组成，循环激素胰岛素、瘦素和脂联素的水平，对葡萄糖和胰岛素的敏感性， 以及脂肪细胞形态和炎症状态。 3) 定义TIE1介导的信号传导机制 体内左心室和乳汁重塑和维护所需。利用 CRISPR/Cas9，我们开发了 在 Tie1 的关键细胞内结构域中存在错义突变的小鼠。独特的特定领域影响 将在产后早期和成年动物中表征 LV 和乳糜管的结构和功能 分别是动态重组和维护过程。 scRNA-seq 和 sc-UniFrac 分析将 用于定义细胞自主和非自主 LEC 亚型所需的 TIE1 依赖性信号传导 出生后调节胃肠道淋巴系统成熟和维持的转录特征。