RBP2 Biology and Pathobiology

RBP2 生物学和病理学

基本信息

批准号：
10736946
负责人：
WILLIAM S BLANER
金额：
$ 68.29万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-06-15 至 2027-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10736946
关键词：
2-arachidonylglycerol Adipose tissue Adult Affect Affinity All-Trans-Retinol Animal Model Binding Binding Proteins Biochemical Biology Body Weight CNR1 gene CNR2 gene Cell Differentiation process Cell Proliferation Cell physiology Cell surface Cells Cellular biology Chromatin Colon Complex Desire for food Development Diet Endocannabinoids Energy Metabolism Enteroendocrine Cell Enzymes Fasting Fatty acid glycerol esters G-Protein-Coupled Receptors GPR119 receptor Genes Genetic Transcription Glucose Glycerol Goals Grant Hepatic High Fat Diet Hormone secretion Hydrolase Immune response Impairment In Vitro Inflammation Intestines Killer Cells Knockout Mice L Cells Ligands Link Maintenance Mediating Metabolic Metabolic Diseases Metabolism Methodology Molecular Weight Monoacylglycerol Lipases Monoglycerides Motivation Mus Nerve Degeneration Nociception Nuclear Hormone Receptors Nutrient availability Oral Organoids Pathway interactions Phenotype Physiological Proliferating Proteins Publishing RBP4 gene Reporting Retinaldehyde Retinoic Acid Binding Retinoic Acid Receptor Retinoic Acid Response Element Retinoids Retinol Binding Proteins Rewards Role Secretory Vesicles Signal Pathway Signal Transduction Small Intestines Smooth Muscle Tretinoin Triglycerides Vitamin A Weight Gain Wild Type Mouse Work aldehyde dehydrogenases anandamide cell growth cell type cognitive function dietary gastric inhibitory polypeptide receptor glucagon-like peptide 1 glucose metabolism hormone regulation human model in vivo incretin hormone interest lipid metabolism lipoprotein lipase metabolic phenotype mood regulation neurogenesis oxidation prevent response retinoic acid receptor alpha retinoic acid receptor gamma uptake

项目摘要

ABSTRACT The goal of this project has been and remains to gain understanding of the biochemical basis for our observation that retinol-binding protein 2 (RBP2) has an unsuspected role in the maintenance of body weight, normal responses to a glucose challenge, and normal fasting hepatic triglyceride levels. We found that when maintained solely on a control chow diet, 6-7-month-old Rbp2-deficient (Rbp2-/-) mice accrue significantly more body weight as white adipose tissue (WAT), respond significantly less well to a glucose challenge, and possess significantly more hepatic fat than matched wild type (WT) littermate controls. These phenotypes were fully recapitulated by younger 55-day old Rbp2-/- and matched WT mice fed a high fat diet for 6-7 weeks. Our published work establishes that both RBP2 and retinol-binding protein 4 (RBP4) are expressed in enteroendocrine cells (EECs) within the gut, including by glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) expressing cells. Rbp2-/- mice show elevated circulating GIP levels in response to an oral fat challenge. We further showed that RBP2 binds long-chain unsaturated 2- monoacylglycerol (2-MAGs) with an equally high affinity as it does retinol and is consequently a physiologically relevant 2-MAG-binding protein as well as a retinoid-binding protein. We identified that Rbp4-/- mice have significantly diminished circulating GIP concentrations both fasting and after an oral fat challenge compared to WT controls. RBP4 localizes to EEC secretory granules and is co-secreted along with GIP upon stimulation of cultured EEC-enriched primary mouse intestinal cells. Since elevated GIP levels are associated with increased body weight and adipose mass in both humans and animal models, we hypothesize that this contributes to the metabolic phenotypes seen for Rbp2-/- mice. We are proposing 3 Specific Aims exploring the actions of RBP2, RBP4, retinoid- and 2-MAG signaling in regulating EEC activities and synthesis/secretion of GIP and GLP-1. Specific Aim 1 will assess the involvement of RBP2, all-trans-retinoic acid (ATRA) and ATRA-RAR signaling, and RBP4 in modulating EEC responses. This entails both in vivo and in vitro studies. Specific Aim 2 will assess the involvement of 2-MAGs and enzymes responsible for 2-MAG synthesis (diacylglycerol lipase (DAGL)), 2-MAG degradation (monoacylglycerol lipase (MAGL) and α/β hydrolase domain 6 and 12 (ABDH6 and ADBH12)) and 2-MAG actions (the cell surface cannabinoid receptors 1 and 2 (Cb1 and Cb2) and GPR119 receptors) in modulating K-cell responses to dietary nutrient availability. These studies will make use of the same methodologies employed in Specific Aim 1. Specific Aim 3 will provide greater understanding of whether RBP2 has a direct role in GLP-1 synthesis/secretion in both the small intestine and in the colon. Although we have reported the presence of RBP2 protein in L-cells, unlike GIP and K-cells, we have not systematically studied GLP-1 or L-cell biology from the perspective of what role RBP2 may have in this biology.

抽象的该项目的目标一直存在，并且仍将了解我们的生化基础观察到视黄醇结合蛋白2（RBP2）在体重的维持中具有毫无疑问的作用，对葡萄糖挑战的正常反应和正常的禁食肝甘油三酸酯水平。我们发现什么时候仅维持6-7个月大的RBP2缺陷型（RBP2 - / - ）小鼠的饮食仅维持饮食。体重为白色脂肪组织（WAT），对葡萄糖挑战的反应明显较小，并且拥有肝脂肪比匹配的野生型（WT）窝窝对照更大。这些表型完全由55天老的RBP2 - / - 概括，喂养高脂饮食6-7周的匹配的WT小鼠。我们发表的工作确定RBP2和视黄醇结合蛋白4（RBP4）均在肠道内的肠内分泌细胞（EEC），包括通过葡萄糖依赖性胰岛素多肽（GIP）和胰高血糖素样肽1（GLP-1）表达细胞。 RBP2 - / - 小鼠显示出循环升高的GIP水平对口腔脂肪挑战的反应。我们进一步表明，RBP2结合长链不饱和2- 单酰甘油（2毫克）具有同样高的亲和力，与视黄醇一样高，因此是一种物理上的相关的2-MAG结合蛋白以及类维生素性结合蛋白。我们确定RBP4 - / - 小鼠具有与之相比 WT控件。 RBP4本地定位于EEC分泌颗粒，并在刺激后与GIP共同分泌富含EEC的原代小鼠肠细胞。由于GIP升高与增加有关人类和动物模型中的体重和脂肪质量，我们假设这有助于 RBP2 - / - 小鼠可见的代谢表型。我们提出了3个特定目标，以探索RBP2的动作，在调节EEC活性以及GIP和GLP-1的合成/分泌中，RBP4，类视感和2-MAG信号传导。具体目标1将评估RBP2，全反击酸（ATRA）和ATRA-rar的参与信号传导和调节EEC响应的RBP4。这需要体内和体外研究。具体目标2将评估负责2-MAG合成的2-MAG和酶的参与（二酰基甘油脂肪酶（DAGL）），2-MAG降解（单酰基甘油脂肪酶（MAGL）和α/β水解酶结构域 6和12（ABDH6和ADBH12）和2-MAG作用（细胞表面大麻素受体1和2（CB1和2 CB2）和GPR119受体）用于调节K-Cell对饮食营养利用率的反应。这些研究会利用在特定目标1中携带的相同方法。具体目标3将对RBP2是否在GLP-1中发挥直接作用提供更深入的了解小肠和结肠中的合成/分泌。尽管我们报告了存在 L细胞中的RBP2蛋白，与GIP和K细胞不同，我们没有系统地研究GLP-1或L细胞生物学 RBP2在这种生物学中可能具有什么作用的观点。