In vivo Osteocyte Ca2+ Signaling in Aging Bone

老化骨骼中的体内骨细胞 Ca2 信号传导

基本信息

批准号：
10590737
负责人：
James Boorman-Padgett
金额：
$ 3.54万
依托单位：
CITY COLLEGE OF NEW YORK
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-05-01 至 2024-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10590737
关键词：
Address Adult Affect Age Age Months Aging Biochemical Biology Biomechanics Bone Resorption Bone remodeling Calcium Channel Calibration Cells Characteristics Cities Consensus Data Development Fellowship Female Frequencies Generations Goals Grant Growth Hormonal Change Image In Vitro Knowledge Laboratories Life LoxP-flanked allele Measurement Measures Mechanics Mentors Metatarsal bone structure Modeling Mus New York Osteoblasts Osteoclasts Osteocytes Osteogenesis Osteoporosis prevention P2X-receptor Pattern Periodicity Physiological Physiology Piezo 1 ion channel Population Reporter Research Role Signal Transduction Skeleton Solid Speed TNFSF11 gene TRPV channel Tamoxifen Testing Time Training Visualization aged antagonist bone bone aging bone fragility bone health calcium indicator career college cortical bone dentin matrix protein 1 imaging approach in vivo individual response male mechanical load mechanotransduction middle age mouse model multiphoton imaging multiphoton microscopy new therapeutic target novel recruit response young adult

项目摘要

Abstract Bone’s ability to respond and adapt to mechanical loading declines significantly with age, which is a major contributor to bone fragility. We do not understand how alterations in osteocyte mechanical sensing occur in aging bone. This is a critical knowledge gap given the central role for osteocytes in orchestrating bone formation and resorption responses. Recent breakthrough discoveries from my mentor’s laboratory revealed how osteocytes in living bone perceive and encode mechanical loading information. They created the first ever reporter mice with an osteocyte-targeted genetically encoded calcium indicator to allow measurement of osteocyte Ca2+ responses to loading in vivo. They discovered that osteocyte populations in living bone numerically encode load magnitude, with increasing strain levels recruiting more Ca2+ responding osteocytes in healthy young adult bone following a robust, linear response curve. Preliminary studies further revealed that this osteocyte loading response curve changes markedly with systemic challenge. The proposed F31 training grant will determine how osteocyte Ca2+ responses to mechanical loading in vivo change with age. In Aim 1, we will create tamoxifen inducible GCaMP6f mice in which the Ca2+ reporter can be turned on at selective times throughout adulthood. This will address challenges inherent in long-term constitutive GCaMP expression as was used in the first-generation osteocyte Ca2+ reporter mice previously created by our laboratory. Metatarsal bones will be loaded in vivo through the range of physiological strain levels using a combined loading and multiphoton imaging approach and osteocyte Ca2+ responses in cortical bone will be measured. In Aim 2, we will use these inducible GCaMP6f mice to assess osteocyte Ca2+ responses to loading in young adult, middle aged, and aged adult mice. Finally, a range of channels (eg, T-type and L-type channels, Panx1-P2X7, Piezo 1, TRPV channels) are implicated in osteocyte Ca2+ response to loading in vitro. However, the in vivo importance of these channels is poorly understood. In the exploratory studies in Aim 3, we will use validated selective channel antagonists to test how modulating channel function in vivo influences load- response curves. Relevance to F31 grant Scientific and Training goals: Research: These studies will be the first to examine osteocyte mechano-sensing in vivo throughout adult life. Training: The proposed fellowship incorporates a broad range of experimental and analytical approaches (mouse models, bone biomechanics, in vivo studies, multiphoton imaging, cell Ca2+ measurements, bone and osteocyte physiology, channel biology) that will provide a robust platform for research career growth.

抽象的骨的响应能力和适应机械负荷随着年龄的增长而大幅下降，这是一个主要的造成骨骼脆弱的贡献者。我们不了解骨细胞机械感应的改变在衰老的骨骼中。鉴于骨细胞在编排骨骼中的核心作用，这是一个关键的知识差距形成和分辨率响应。我心理实验室的最新突破发现揭示了活骨中的骨细胞如何感知和编码机械负载信息。他们创建了有史以来的第一只记者小鼠，它具有骨细胞针对的一般编码钙指示器允许测量骨细胞Ca2+对体内加载的反应。他们发现骨细胞活骨中的种群数值编码负载幅度，并增加应变水平在稳健的线性响应曲线后，健康的年轻成人骨骼中有更多的Ca2+反应骨细胞。初步研究进一步揭示了这种骨细胞加载响应曲线在随着系统性挑战。拟议的F31培训补助金将决定骨细胞Ca2+如何响应机械载荷随着年龄的增长而变化。在AIM 1中，我们将创建他莫昔芬诱导GCAMP6F小鼠在整个成年期，可以在选择性时间打开CA2+记者。这将解决第一代使用的长期构型GCAMP表达中固有的挑战骨细胞CA2+记者小鼠先前由我们的实验室创建。 metatars骨头将被装入使用组合加载和多光子成像的体内通过物理应变水平范围将测量在皮质骨中的接近和骨细胞Ca2+反应。在AIM 2中，我们将使用这些可诱导的GCAMP6F小鼠评估骨细胞Ca2+对年轻人的负载的反应，中年，和老年小鼠。最后，一系列通道（例如，T型和L型通道，Panx1-P2X7，Piezo 1，TRPV通道）在骨细胞Ca2+对体外加载的反应中暗示。但是，体内这些渠道的重要性知之甚少。在AIM 3的探索性研究中，我们将使用经过验证的选择性通道拮抗剂，以测试调节体内的通道功能如何影响负载 - 与F31赠款科学和培训目标有关：研究：这些研究将是在整个成人生活中，第一个在体内检查骨细胞机械感应的人。培训：提议奖学金结合了广泛的实验和分析方法（小鼠模型，骨骼生物力学，体内研究，多光子成像，细胞Ca2+测量，骨和骨细胞生理学，渠道生物学），它将为研究职业增长提供强大的平台。