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Connexin channels in transducing mechanical signals in bone

连接蛋白通道在骨中转导机械信号

基本信息

批准号：
9754577
负责人：
Jean X Jiang
金额：
$ 33.55万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-01 至 2023-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9754577
关键词：
Animal Model Antibodies Attenuated Biological Biomechanics Blocking Antibodies Bone Diseases Bone Matrix Bone Resorption Bone Tissue Bone remodeling Cell Survival Cells Cellular Mechanotransduction Complement Connexin 43 Connexins Cytoskeleton Data Development Dinoprostone Dominant-Negative Mutation Environment Gap Junctions Genes Impairment In Situ In Vitro Integrins Knock-in Mouse Knockout Mice Location MAP Kinase Gene Mechanical Stimulation Mechanical Stress Mechanics Mediating Minerals Modality Modeling Molecular Mutation Osteocytes Osteogenesis Osteopenia Osteoporosis Outcome Phenotype Physiological Play Property Prostaglandins Regulation Research Research Activity Role Signal Transduction TNFSF11 gene Testing Therapeutic Therapeutic Agents Transgenic Mice Transgenic Model WNT Signaling Pathway bone bone cell bone loss cell type drug candidate experience extracellular gap junction channel in vivo knockout gene mechanical load mechanotransduction mouse model mutant new therapeutic target novel novel strategies novel therapeutics response skeletal tissue treatment strategy

项目摘要

Project Summary Mechanical loading experienced by skeletal tissues plays an important role in bone formation and remodeling. Osteocytes are the most abundant bone cell type and the major mechanosensory cells of the bone. They orchestrate bone remodeling from their location throughout bone matrix by coordinating osteoblastic formation and osteoclastic resorption. Osteocytes are connected to neighboring osteocytes and other bone cells via gap junction channels and to extracellular environments via hemichannels. Both types of channels are formed by connexin (Cx) 43. The involvement of Cx43 in response to mechanical stimulation of bone tissue has been shown in gene knockout models; however, the distinct functions of gap junction channels and hemichannels in osteocytes, as well as the mechanism underlying the physiological roles of these channels during mechanical loading remain largely unknown. To dissect the physiological roles of these two types of channels, we have recently developed two transgenic mouse models expressing Cx43 dominant negative mutants predominantly in osteocytes. We are also generating a Cx43 mutant gene knockin mouse model to complement our transgenic models. These mutations impair osteocytic gap junction channels and/or hemichannels. In addition, we have generated antibodies that specifically inhibit Cx43 hemichannels, but not gap junction channels. Moreover, we have developed novel approaches that allow us to assess osteocytic hemichannel activity in situ. Preliminary data show that impairment of Cx43 hemichannels attenuates the anabolic effect of mechanical loading on the bone. We and others have also shown that osteocytic Cx43 hemichannels are opened by mechanical stress, releasing small bone anabolic factors including prostaglandins in vitro. The objective is to determine the specific mechanistic role of Cx43 hemichannels in mediating the anabolic effect of mechanical loading on the skeletal tissues. Three specific aims are proposed: 1) To test the hypothesis that osteocytic Cx43 hemichannels play a crucial role in mediating anabolic function of mechanical loading on skeletal tissue. 2) To test the hypothesis that osteocytic Cx43 hemichannels mediate anabolic function of mechanical loading via PGE2 release, and activation of PGE2 and Wnt signaling. 3) To test the hypothesis that activation and inactivation of Cx43 hemichannels are specifically regulated by integrin activation/cytoskeleton and MAPK signaling, respectively. The proposed studies are expected to have a major positive impact by defining the mechanical transduction mechanism and its regulation in bone tissue, constituting potential, significant contributions toward the development of new therapeutic agents for the treatment of osteoporosis and bone loss.

项目概要骨骼组织承受的机械负荷在骨形成和重塑中起着重要作用。骨细胞是最丰富的骨细胞类型，也是骨骼的主要机械感觉细胞。他们通过协调成骨细胞的形成，从整个骨基质的位置协调骨重塑和破骨细胞吸收。骨细胞通过间隙与邻近的骨细胞和其他骨细胞连接连接通道并通过半通道到达细胞外环境。两种类型的通道都是由连接蛋白 (Cx) 43。Cx43 参与骨组织机械刺激的反应已被证实在基因敲除模型中显示；然而，间隙连接通道和半通道的不同功能骨细胞，以及这些通道在机械作用过程中生理作用的机制装载仍然很大程度上未知。为了剖析这两类通道的生理作用，我们有最近开发了两种主要表达 Cx43 显性失活突变体的转基因小鼠模型在骨细胞中。我们还生成了 Cx43 突变基因敲入小鼠模型来补充我们的研究成果转基因模型。这些突变损害骨细胞间隙连接通道和/或半通道。此外，我们已经产生了特异性抑制 Cx43 半通道但不抑制间隙连接通道的抗体。此外，我们还开发了新的方法，使我们能够原位评估骨细胞半通道活性。初步数据表明，Cx43 半通道受损会减弱机械的合成代谢效应负载在骨头上。我们和其他人还表明，骨细胞 Cx43 半通道是通过机械应力，在体外释放包括前列腺素在内的小骨合成代谢因子。目标是确定 Cx43 半通道在介导机械合成代谢效应中的具体机制作用骨骼组织上的负荷。提出了三个具体目标：1）检验骨细胞的假设 Cx43 半通道在介导骨骼组织机械负荷的合成代谢功能中发挥着至关重要的作用。 2) 检验骨细胞 Cx43 半通道介导机械负荷合成代谢功能的假设通过 PGE2 释放以及 PGE2 和 Wnt 信号传导的激活。 3）检验激活和 Cx43 半通道的失活受到整合素激活/细胞骨架和 MAPK 的特异性调节分别发出信号。拟议的研究预计将通过定义骨组织中的机械传导机制及其调控，构成潜力，意义重大为开发治疗骨质疏松症和骨的新治疗药物做出贡献损失。