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：
10570872
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/10570872
关键词：
Ablation Acetylcholine Adipocytes Adipose tissue Adrenergic Receptor Affect Agonist Calcium Cells Choline O-Acetyltransferase Chronic Communication Complex Cre lox recombination system 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 Macrophage Mediating Metabolic Metabolic Diseases Metabolism Molecular Mus Nicotinic Receptors Obesity Organism Paracrine Communication Pathogenesis Pathologic Physiological Play Production Regulation Reporter Role Series Signal Pathway Signal Transduction Source Spatial Distribution Streptozocin Stromal Cells Testing Tissues Visualization Work beta-2 Adrenergic Receptors cell type cholinergic coping diabetes pathogenesis energy balance experimental study feeding glycemic control in vivo insight interdisciplinary approach loss of function mouse model new therapeutic target novel obesity development paracrine pharmacologic 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.

在过去的二十年里，脂肪免疫细胞和邻近脂肪细胞之间的通讯越来越受到重视，其与肥胖、胰岛素抵抗和糖尿病等代谢性疾病的相关性现在已得到广泛认可。我们最近发现，脂肪细胞内产生乙酰胆碱的免疫细胞。皮下脂肪组织通过 CHRNA2（烟碱乙酰胆碱受体，α2 亚基）的旁分泌机制影响生热米色脂肪的功能。在此，我们建议彻底研究这种免疫米色脂肪的机制。乙酰胆碱信号传导，特别是通过 ChAT+（胆碱乙酰转移酶）巨噬细胞，在生理和病理条件下影响脂肪组织功能和全身代谢稳态。我们的初步研究表明，冷暴露显着增加了皮下脂肪中表达 ChAT 的巨噬细胞的百分比。在各种免疫细胞亚群中基因删除 Chat 的小鼠品系以及仅巨噬细胞删除 Chat 的小鼠品系会消除乙酰胆碱产生的诱导并导致腹股沟产热缺陷在基因模型中使用激动剂进行药理激活的初步研究，包括单敲除 b-AR（肾上腺素能受体）亚型，表明这些 ChAT+ 巨噬细胞是通过 β2-AR 介导的。我们将彻底研究如何介导。使用双报告小鼠系中的培养巨噬细胞 (BMDM) 和脂肪驻留巨噬细胞激活这些胆碱能巨噬细胞（ChAT-Cre；tdTomato；ChATBAC-eGFP）将在 Adipo-Clear 制备的皮下脂肪中可视化 ChAT+ 细胞的体内空间分布，并将进行单细胞 RNA 测序来表征这些细胞的转录组景观。我们将研究 Ca2+ 流入如何影响激活的米色脂肪细胞中的 CHRNA2 下游信号传导。初步结果表明，新产生的 Chrna2HA-Cre 敲入小鼠可能。我们还建议使用该小鼠模型来表征米色脂肪中含有 CHRNA2 的离子通道复合物的组成。我们将研究乙酰胆碱-CHRNA2 信号在整个发育过程中受到的影响。我们建议研究 CHRNA2 介导的米色脂肪激活如何促进对链脲佐菌素引起的血糖控制丧失的适应性反应。关键实验的条件已经得到优化。我们已经招募了一组合作者，利用跨学科方法开展拟议的研究，最终，了解该电路的机制将引导我们找到对抗人类代谢紊乱的新分子和细胞候选药物。