Improving Aged Neuromuscular Health and Function

项目摘要 神经肌肉功能和再生能力的丧失是衰老的标志；然而，导致这一年龄的原因- 相关的下降和这一过程背后的分子途径仍然未知，也没有临床干预 成功地阻止了与年龄相关的神经肌肉功能障碍。 这项建议的长期目标是开发一种有效的干细胞介导的疗法来改善 与年龄相关的神经肌肉功能恶化。我们之前发表的研究结果表明，移植 我们独特的成年多潜能肌源性干细胞/祖细胞(MDSPC)来自幼鼠的促进 坐骨神经缺陷小鼠功能性周围神经再生延缓衰老相关疾病的发生 疾病，并使早衰症小鼠的寿命延长三倍。此外，诱导血管新生 肌肉和大脑--在那里没有检测到移植细胞--强烈表明一种治疗方法 旁分泌/内分泌机制。最重要的是，我们最近的初步结果表明，系统性 将年轻的MDSPC移植到自然衰老的小鼠体内可以恢复周围神经的组织学和髓鞘形成， 增加骨骼肌重量和纤维横截面积，减少肌肉纤维化，并改善 功能活动和步态。这些新发现有力地表明，年轻的MDSPC可以调节 通过分泌激活或抑制关键分子的返老性因子为老年动物提供系统环境 对组织再生至关重要的信号通路。因此，我们假设年轻的干细胞--或者说 它们分泌的治疗因子可用于治疗与衰老相关的慢性神经肌肉损伤。 在目标1中，我们将确定用年轻的MDSPC进行系统治疗可以在多大程度上恢复活力。 应用临床相关技术研究自然衰老小鼠的神经肌肉组织结构和运动功能 如实时共振反射光谱(RRS)、肌肉收缩力测量、神经 传导测试，以及活动能力、步态和肌肉疲劳的纵向运动功能测试。在目标2中，我们将 确定神经肌肉功能改善的潜在分子机制(S) 年轻的MDSPC的移植，使用多路串联质谱仪和[磷酸蛋白质组学]，AS 以及识别参与这一系统复兴的血清中循环的蛋白质。《目标3》将揭开 年轻的MDSPC分泌的推动神经肌肉组织再生和改善功能的关键因子 一种定量多重抗体阵列系统。 总之，这些目标将揭示年轻的MDSPC介导的神经肌肉组织的机制 恢复活力和功能改善，确定预测神经肌肉健康的循环生物标记物 这有助于发现新的以干细胞为基础的临床治疗靶点。

Project Summary Loss of neuromuscular function and regenerative capacity is a hallmark of aging; however, the cause of this age- related decline and the molecular pathways underlying this process remain unknown and no clinical intervention successfully arrests age-related neuromuscular dysfunction. The long-term objective of this proposal is to develop an effective stem cell-mediated therapy to ameliorate age-related deterioration of neuromuscular function. Our previously published findings show that transplantation of our unique adult multipotent muscle-derived stem/progenitor cells (MDSPCs) from young mice promotes functional peripheral nerve regeneration in mice with a sciatic nerve defect, delays the onset of aging-related diseases, and triples the lifespan in mouse models of progeria. In addition, induced neovascularization in the muscles and brain—where no transplanted cells were detected—strongly suggests a therapeutic paracrine/endocrine mechanism. Most importantly, our recent preliminary results indicate that systemic transplantation of young MDSPCs into naturally aged mice restores peripheral nerve histology and myelination, increases skeletal muscle weight and fiber cross-sectional area, decreases muscle fibrosis, and improves functional mobility and gait. These novel findings strongly suggest that young MDSPCs can modulate the systemic environment of aged animals through secreted rejuvenating factors that activate or inhibit key molecular signaling pathways critical for tissue regeneration. Thus, we hypothesize that young stem cells—or the therapeutic factors they secrete—can be used to treat chronic aging-related neuromuscular impairments. In Aim 1, we will determine to what extent systemic treatment with young MDSPCs can rejuvenate neuromuscular tissue structure and motor function in naturally aged mice by using clinically relevant techniques such as real-time Resonant Reflection Spectroscopy (RRS), muscle contractile force measurement, nerve conduction testing, and longitudinal motor function testing of mobility, gait, and muscle fatigue. In Aim 2, we will identify the underlying molecular mechanism(s) of neuromuscular functional improvements resulting from transplantation of young MDSPCs, using multiplexing-tandem mass spectrometry and [phosphoproteomics], as well as identify proteins circulating in the blood serum involved in this systemic rejuvenation. Aim 3 will uncover key factors secreted by young MDSPCs that drive neuromuscular tissue rejuvenation and improve function using a quantitative multiplex antibody array system. Together, these aims will uncover the mechanisms of young MDSPC-mediated neuromuscular tissue rejuvenation and functional improvements, identify circulating biomarkers that predict neuromuscular health in aged mammals, and facilitate the discovery of novel stem cell–based therapeutic targets for clinical use.