IntBIO: Linking genome to phenome to understand the function of Masticatory Myosin

IntBIO：将基因组与表型组联系起来以了解咀嚼肌球蛋白的功能

• 批准号: 2217246
• 负责人: Nicolai Konow
• 金额: $ 213.47万
• 依托单位: University of Massachusetts Lowell
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2217246&HistoricalAwards=false
• 关键词: IntBIO; Linking; genome; phenome; understand

Muscles provide the primary means for animals to produce force, move, and interact with their environment. Muscle function is a consequence of hierarchical structure from molecular to whole muscle and muscle/skeletal systems. However, deep understanding of how muscles work is limited by research that does not fully cross these scales. Multiscale studies that investigate how genes encode proteins, how trillions of proteins of different kinds interact, how muscle mass and shape influence contraction, and how skeletal geometry tunes the speed and forcefulness of movements are the best avenue for enabling new insights into muscle performance. This project leverages the synergy of state-of-the-art, multiscale experimental techniques, and mathematical modeling of muscle, to understand bite performance in rodent models. Rodents have a range of bite strategies, jaw geometries, and muscle protein compositions, including a unique type of the muscle motor-protein myosin called masticatory myosin. Previous studies have suggested that masticatory myosin has exceptional properties that could provide new insights into how muscles produce bite forces. This project will test whether bite performance is influenced primarily by muscle size and shape, skeletal geometry, or the presence of masticatory myosin. Insights gathered from this integrative complement of studies will inform future studies of how muscle function is controlled by features of muscle tissue. In the broader impact activities of this project, the principle that biological function is “more than the sum of its parts” will be introduced through a custom-coded computer game that will teach secondary school students from groups underrepresented in STEM about how muscles function.Understanding complex biological systems like muscle is challenging without multiscale convergence approaches, such as those used in this project. A fundamental idea in muscle physiology is the trade-off between force and velocity. However, a masticatory isoform of the myoprotein myosin has been suggested to be both forceful and fast. Unique mechanochemistry of two molecular loop sequences connecting myosin functional domains could explain this paradoxical phenomenon. This idea will be tested using targeted mutagenesis of C2C12 muscle cells, in-vitro motility assays, and single-fiber experiments that measure peak and loaded velocity of diverse myosin aggregates. An alternate idea is that fast and strong performance of jaw muscles with masticatory myosin is due to organ- to organism-scale differences in muscle size, geometry, bite type, and biomechanics that can buffer myosin force or speed limitations. This idea will be tested in experiments where muscle activation, strain, force, and leverage dynamics are measured using electromyography, sonomicrometry, micro force-buckles, and X-ray Reconstruction of Moving Morphology during biting on food items with controlled size and varying hardness. These methods will permit determination of the realized force-velocity of biting. Rodents are ideal for determining the cross-scale mechanistic bases of force-velocity modulation, as phenotypes exist with distinct myosin isoform expression but shared bite biomechanics. Force-velocity relationships across biological scales (actomyosin, myofibers, intact muscles, and whole feeding systems) will be coupled using a subtractive approach, and multiscale mathematical muscle modeling will be used to determine the mechanistic bases for emergent performance in geometrically similar or different rodents that either possess or lack masticatory myosin.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

肌肉为动物提供了产生力量、移动和与环境相互作用的主要手段。肌肉功能是从分子到整个肌肉和肌肉/骨骼系统的分级结构的结果。然而，对肌肉如何工作的深入理解受到没有完全跨越这些尺度的研究的限制。研究基因如何编码蛋白质，数万亿不同种类的蛋白质如何相互作用，肌肉质量和形状如何影响收缩，以及骨骼几何形状如何调整运动的速度和力量的多尺度研究是实现对肌肉性能的新见解的最佳途径。该项目利用最先进的多尺度实验技术和肌肉数学建模的协同作用，以了解啮齿动物模型的咬合性能。啮齿动物有一系列的咬策略，颌骨几何形状和肌肉蛋白质组成，包括一种独特类型的肌肉运动蛋白肌球蛋白称为咀嚼肌球蛋白。以前的研究表明，咀嚼肌球蛋白具有特殊的特性，可以为肌肉如何产生咬合力提供新的见解。这个项目将测试咬合性能是否主要受肌肉大小和形状，骨骼几何形状，或咀嚼肌球蛋白的存在。从这种综合补充研究中收集的见解将为未来的研究提供信息，即肌肉功能如何受肌肉组织特征的控制。 在该项目的更广泛的影响活动中，将通过定制编码的电脑游戏介绍生物功能“大于其各部分之和”的原理，该游戏将向STEM中代表性不足的中学生教授肌肉的功能。如果没有像本项目中使用的多尺度收敛方法，理解肌肉这样复杂的生物系统是具有挑战性的。肌肉生理学中的一个基本思想是力和速度之间的权衡。然而，肌蛋白肌球蛋白的咀嚼亚型被认为既有力又快速。连接肌球蛋白功能域的两个分子环序列的独特机械化学可以解释这种矛盾现象。这一想法将使用C2 C12肌细胞的靶向诱变，体外运动试验和单纤维实验，测量峰值和加载速度的不同肌球蛋白聚集体进行测试。另一种想法是，咀嚼肌球蛋白的下颌肌肉的快速和强大的性能是由于肌肉大小，几何形状，咬合类型和生物力学的器官-生物体规模的差异，可以缓冲肌球蛋白力或速度限制。这一想法将在实验中进行测试，其中肌肉激活，应变，力和杠杆动力学测量使用肌电图，sonomicrometry，微力，和移动形态的X射线重建过程中咬的食物控制的大小和不同的硬度。这些方法将允许确定实现的咬合力-速度。啮齿动物是理想的确定力-速度调制的跨尺度机械基础，因为表型存在不同的肌球蛋白亚型表达，但共享咬合生物力学。跨生物尺度的力-速度关系（肌动球蛋白、肌纤维、完整的肌肉和整个进食系统）将使用消减方法偶联，和多尺度数学肌肉建模将用于确定具有或缺乏咀嚼肌球蛋白的几何相似或不同啮齿动物的紧急性能的机械基础。该奖项反映了NSF的法定使命，并被认为值得通过以下方式获得支持：使用基金会的知识价值和更广泛的影响审查标准进行评估。