The role of immune-adipocyte cholinergic signaling during metabolic adaptation and dysfunction

免疫脂肪细胞胆碱能信号在代谢适应和功能障碍中的作用

基本信息

批准号：
10202938
负责人：
Jun Wu
金额：
$ 41.81万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-01-11 至 2025-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10202938
关键词：
Acetylcholine Adipocytes Adipose tissue Adrenergic Receptor Affect Agonist Calcium Cells Choline O-Acetyltransferase Chronic Communication Complex Data Defect Diabetes Mellitus Fatty acid glycerol esters Functional disorder Genetic Genetic Models Hand High Fat Diet Homeostasis Human Immune In Vitro Insulin Resistance Investigation Ion Channel Knock-in Mouse Knock-out Lead Mediating Metabolic Metabolic Diseases Metabolism Molecular Mus Nicotinic Receptors Obesity Organism Paracrine Communication Pathogenesis Pathologic Pharmacology Physiological Play Production Regulation Reporter Role Series Signal Pathway Signal Transduction Source Spatial Distribution Streptozocin Stromal Cells System Testing Tissues Work beta-2 Adrenergic Receptors cell type cholinergic diabetes pathogenesis energy balance experimental study feeding glycemic control in vivo insight interdisciplinary approach loss of function macrophage mouse model new therapeutic target novel obesity development paracrine recruit response single-cell RNA sequencing subcutaneous thermal stress three-dimensional visualization tool transcriptome

项目摘要

The communication between adipose immune cells and neighboring adipocytes has become increasingly appreciated over the past two decades, and its relevance to metabolic disorders such as obesity, insulin resistance and diabetes is now well-recognized. We have recently discovered that acetylcholine-producing immune cells within subcutaneous adipose tissue influence thermogenic beige fat function through paracrine mechanisms via CHRNA2 (nicotinic acetylcholine receptor, alpha2 subunit). Here we propose to thoroughly investigate how this immune-beige fat acetylcholine signaling, particularly via ChAT+(choline acetyltransferase) macrophages, influences adipose tissue function and whole body metabolic homeostasis under physiological and pathological conditions. Our preliminary studies reveal that cold exposure significantly increased percentage of macrophages that express ChAT in subcutaneous fat. We have generated multiple mouse lines with genetic deletion of Chat in various immune cell subsets and only macrophage deletion of Chat ablated induction of acetylcholine production and rendered thermogenic defects in inguinal fat upon cold exposure. Preliminary studies with pharmacological activation using agonists in genetic models including single knockouts of subtype of the b-ARs (adrenergic receptors), suggested that these ChAT+ macrophages are mediated through β2-AR. Aim 1. We will thoroughly investigate how these cholinergic macrophages are activated using both cultured macrophages (BMDM) and adipose resident macrophages in a double reporter mouse line (ChAT-Cre;tdTomato;ChATBAC-eGFP). Spatial distribution of ChAT+ cells in vivo will be visualized in Adipo-Clear prepared subcutaneous fat and single cell RNA-seq will be carried out to characterize the transcriptome landscape of these cells. Aim 2. We will investigate how Ca2+ influx influences CHRNA2 downstream signaling in activated beige adipocytes. Preliminary results indicated that newly generated Chrna2HA-Cre knockin mice may provide a functional beige selective Cre system for the field. We also propose to characterize the composition of the CHRNA2-containing ion channel complex in beige fat using this mouse model. Aim 3. We will investigate how acetylcholine-CHRNA2 signaling is affected throughout the development of obesity. We propose to study how CHRNA2 mediated beige fat activation contributes to the adaptive response to streptozotocin-induced loss of glycemic control. All required tools and genetic models are at hand and have been validated. Conditions for key experiments have been optimized. A team of collaborators have been recruited to carry out proposed studies with interdisciplinary approaches. Ultimately, understanding the mechanisms underlying this circuitry will lead us to new molecular and cellular candidates counteracting human metabolic disorders.

在过去的二十年中，脂肪免疫细胞与邻近的脂肪细胞之间的通信越来越受到赞赏，并且与肥胖，胰岛素抵抗和糖尿病等代谢疾病的相关性现在得到了充分认识。我们最近发现，皮下脂肪组织内的乙酰胆碱产生的免疫细胞通过CHRNA2（烟碱乙酰胆碱受体，α2亚基）通过旁分泌机制影响热米色脂肪功能。在这里，我们建议彻底研究这种免疫米脂肪乙酰胆碱信号传导，尤其是通过CHAT+（胆碱乙酰转移酶）巨噬细胞的巨噬细胞如何影响脂肪组织功能和在身体和病理条件下的全身代谢稳态。我们的初步研究表明，冷暴露显着增加了皮下脂肪中表达聊天的巨噬细胞百分比。我们已经在各种免疫小子子集中产生了多种小鼠聊天的遗传缺失，并且仅在冷暴露后，仅对乙酰胆碱产生的聊天消融诱导的巨噬细胞缺失，并在腹股沟脂肪中产生热缺陷。在药理激活的初步研究中，使用激动剂在遗传模型中，包括B-ARS亚型（肾上腺素受体）的单一敲除，这表明这些CHAT+巨噬细胞是通过β2-AR介导的。 AIM 1。我们将彻底研究如何使用培养的巨噬细胞（BMDM）和脂肪居民巨噬细胞（CHAT-CRE; TDTOMATO; CHATBATO; CHATBAC-EGFP）激活这些胆碱能巨噬细胞。聊天+细胞体内的空间分布将在脂肪清晰准备的皮下脂肪中可视化，并将进行单细胞RNA-seq，以表征这些目标2的转录组景观。我们将研究Ca2+影响CAC2+如何影响CHRNA2在活性米味脂肪细胞中的ChRNA2下游信号。初步结果表明，新生成的CHRNA2HA-CRE敲击蛋白小鼠可以为该场提供功能性的米色选择性CRE系统。我们还建议使用该小鼠模型表征米色脂肪中含ChRNA2的离子通道复合物的组成。 AIM 3。我们将研究乙酰胆碱-CHRNA2信号在整个肥胖过程中如何影响。我们建议研究CHRNA2介导的米色脂肪激活如何有助于对链霉菌素诱导的血糖控制丧失的适应性反应。所有必需的工具和遗传模型都在现场，并且已经经过验证。关键实验的条件已优化。已经招募了一组合作者，以跨学科的方法进行拟议的研究。最终，了解该电路的基础机制将使我们成为应对人类代谢疾病的新分子和细胞候选者。