Genetic control of bone structure

骨骼由两个组织结构组成：皮质骨，一种高体积分数的材料，形成长骨的外壳和中心轴；松质骨，位于内部和骨端的开放的格子，具有高孔隙率。到目前为止，骨组织工程还没有考虑到这两种结构的不同的基因调控。这项工作的目标是分别在松质骨和皮质骨的调节背景下检查与年龄相关的遗传和分子机制。所获得的信息对于了解和复制骨组织的形成、维持和退变至关重要。这些新的数据将用于确定抑制或刺激基因表达的遗传靶点和途径，以及/或用于刺激和促进体内骨形成的包膜特异性信号机制。主要的更广泛的影响目标侧重于利用这项研究和促进妇女参与STEM教育和学术事业的行政作用。该奖项由材料研究部的生物材料计划通过BioMaps计划共同资助。骨骼由两个组织结构组成：皮质骨，一种高体积分数的材料，形成长骨的外壳和中心轴；松质骨，位于内部和骨骼末端的开放格子，具有高孔隙率。因此，如果有人试图复制这两种结构，它们不同的基因控制是至关重要的。松质骨和皮质骨有不同的发育途径，对生物物理刺激的适应也不同。例如，机械负荷是一种合成代谢的生物物理刺激，可以增加骨量，并可以逆转成年人的骨丢失。机械生物学的适应性是不同的，是松质骨或皮质骨特有的。这两个结构受疾病的影响是不同的，通常松质层的影响比皮质更大。不同的反应可能反映了两个组织之间不同的发育和机械感觉基因调控。然而，个体组织结构中的基因表达在生长过程中或对负荷的适应中尚未被检测到。骨骼基因表达的潜在途径已经用基因敲除小鼠进行了研究，或者对没有区分这两种组织类型的整个骨骼进行了基因分析。这项拟议工作的总体假设是，活体皮质骨和松质骨中的基因表达不同，导致这两个组织在生长过程中以及在机械载荷等扰动下的基因表达差异。研究小组已经证明：松质骨和皮质骨可以分别从生长期小鼠的胫骨干骺端分离出来；有足够的mRNA可用于横切；松质骨和皮质骨在生长期小鼠中表达不同的基因。利用RNA测序和通路分析，该项目将1)定量测定生长期和成年雌性小鼠胫骨中松质和皮质骨中年龄相关基因的表达；2)通过体内负荷后生长期和成年雌性小鼠胫骨中的差异基因表达，寻找刺激合成代谢成骨的潜在新靶点；3)利用PI的实验室建立的一种有区别地影响松质骨和皮质骨组织的机械转导模型，确定刺激合成代谢骨形成的潜在靶点。所获得的信息对于了解和复制骨组织的形成、维持和退变至关重要。这些新的数据将用于确定抑制或刺激基因表达的遗传靶点和途径，以及/或用于刺激和促进体内骨形成的包膜特异性信号机制。主要的更广泛的影响目标侧重于利用这项研究和促进妇女参与STEM教育和学术事业的行政作用。具体地说，国际和平研究所将：1)通过基于拟议研究的研讨会让中学女孩参与STEM学习；2)让女学生参加她的研究实验室；以及3)增加学术界STEM系的女教员。

PI: van der Meulen, Marjolein C.Proposal #: 1605935The bones of the skeleton consist of two tissue structures: cortical bone, a high volume fraction material forming the outer shell and central shafts of long bones; and, cancellous bone, an open lattice with high porosity located in the interior and bone ends. To date bone tissue engineering has not considered the distinct genetic regulation of these two structures. The goal of this work is to examine age-related genetic and molecular mechanisms in the context of regulation of cancellous and cortical bone separately. Information obtained is critical to understanding and replicating bone tissue formation, maintenance and degeneration. The novel data will be used to identify genetic targets and pathways to inhibit or stimulate gene expression and/or envelope-specific signaling mechanisms to stimulate and enhance bone formation in vivo. The major broader impact objectives are focused on using this research and the PI's administrative role to enhance the participation of women in STEM education and academic careers. This award is co-funded by the Biomaterials program in the Division of Materials Research through the BioMaPs program.The bones of the skeleton consist of two tissue structures: cortical bone, a high volume fraction material forming the outer shell and central shafts of long bones; and, cancellous bone, an open lattice with high porosity located in the interior and bone ends. Thus their distinct genetic control is critical if one seeks to replicate these two structures. Cancellous and cortical bone have different developmental pathways and adapt differently to biophysical stimuli. For example, mechanical loading is an anabolic biophysical srtimulus that increases bone mass and can reverse bone loss in the adult. Mechanobiologic adaptation differs and is specific to cancellous or cortical bone. The two structures are differentially affected by disease, often with greater cancellous effect than cortical. The differing responses likely reflect different developmental and mechanosensory gene regulation between the two tissues. However, gene expression in the individual tissue structures has not been examined during growth or with adaptation to loading. The pathways underlying skeletal gene expression have been studied using knockout mice or with gene analyses of whole bones that do not differentiate between the two tissue types. The overall hypothesis of the proposed work is that gene expression differs in cortical and cancellous bone in vivo, leading to differential gene expression between the two tissues during growth and with perturbations such as mechanical loading. The research team has demonstrated: cancellous and cortical bone can be isolated individually from the tibial metaphysis of growing mice; sufficient mRNA is available and suitable for transciptomics; and, cancellous and cortical bone express different genes in growing mice. Using RNA-sequencing and pathway analysis, this project will 1) quantitate age-related gene expression in cancellous and cortical bone separately in the tibiae of growing and adult female mice; and, 2) identify potential new targets to stimulate anabolic bone formation using differential gene expression in the tibia of growing and adult female mice after in vivo loading, a mechanotransduction model developed by the PI's laboratory that differentially affects cancellous and cortical bone tissue. Information obtained is critical to understanding and replicating bone tissue formation, maintenance and degeneration. The novel data will be used to identify genetic targets and pathways to inhibit or stimulate gene expression and/or envelope-specific signaling mechanisms to stimulate and enhance bone formation in vivo. The major broader impact objectives are focused on using this research and the PI's administrative role to enhance the participation of women in STEM education and academic careers. Specifically the PI will: 1) engage middle school girls in STEM learning via workshops based on the proposed research; 2) involve female students in her research laboratory; and, 3) increase women faculty in STEM departments in academia.