Muscle regeneration through stem cell transplantation

描述(由申请人提供)： 我们最近使用一种改进的预板技术从正常小鼠骨骼肌中分离出3种肌源性细胞，根据它们的黏附特性和增殖行为。虽然其中2个群体具有卫星细胞特征，但第三个群体由表达造血干细胞标志物的长期增殖(LTP)细胞组成。LTP细胞的干细胞特征包括在培养(自我更新)中保持其表型超过30代的能力，并分化为各种谱系，包括肌肉、神经、成骨和内皮细胞。与卫星细胞移植相比，LTP细胞移植显著提高了肌肉再生的效率，并将dystrophin输送到营养不良肌肉中。我们建议的项目的总体目标是进一步研究LTP细胞的重要特征(即，与提高移植能力相关的来源和机制)，这些特征对于它们在移植中促进肌肉再生和将dystrophin输送到营养不良的肌肉是至关重要的。在这个项目中，我们将通过确定它们与卫星细胞和来自骨骼肌的侧群(SP)干细胞的关系来研究LTP细胞的潜在来源(目标1)。我们随后将研究LTP细胞在骨骼肌中表现出提高移植能力的机制。我们将评估细胞增殖和分化动力学的相对影响(目标2)，并确定免疫特权细胞行为也在骨骼肌LTP细胞再生能力增强中发挥作用的可能性(目标3)。对LTP细胞自我更新和多潜能能力的相对重要性的分析将阐明干细胞特性对提高骨骼肌移植能力的贡献(目标#4)。这个项目可能会增加我们对显示干细胞特征的肌源性细胞群体的基本生物学的理解。这反过来可能会揭开新的技术面纱，通过移植肌源性干细胞来改善营养不良或受损的骨骼肌的肌肉再生。

DESCRIPTION (provided by applicant): We recently have used a modified preplate technique to isolate 3 populations of myogenic cells from normal mouse skeletal muscle based on their adhesion characteristics and proliferation behaviors. Although 2 of these populations display satellite cell characteristics, the third population consists of long_term proliferating (LTP) cells expressing hematopoietic stem cell markers. The stem cell characteristics of the LTP cells include the abilities to retain their phenotype for more than 30 passages in culture (self-renewal) and to differentiate into various lineages, including muscle, neural, osteogenic, and endothelial. The transplantation of the LTP cells, in contrast to satellite cell transplantation, significantly improved the efficiency of muscle regeneration and dystrophin delivery to dystrophic muscle. The overall goal of our proposed project is to further investigate important features of the LTP cells (i.e., sources and mechanisms involved with the improved transplantation capacity) that are paramount to their potential use in transplantation to improve muscle regeneration and deliver dystrophin to dystrophic muscle. In this project we will investigate potential sources of the LTP cells by determining their relationship to satellite cells and to the Side Population (SP) stem cells derived from skeletal muscle (Aim #1). We subsequently will investigate mechanisms by which the LTP cells display an improved transplantation capacity in skeletal muscle. We will evaluate the relative effects of the proliferation and differentiation kinetics of the cells (Aim #2) and determine the possibility that immune_privileged cell behavior also plays a role in the increased regenerative capacity of LTP cells in skeletal muscle (Aim #3). Analysis of the relative importance of the LTP cells' self-renewal and multipotent capabilities will shed light on the contribution of stem cell characteristics to the improved transplantation capacity in skeletal muscle (Aim #4). This project might increase our understanding of the basic biology of myogenic cell populations that display stem cell characteristics. This in turn may unveil new techniques to improve muscle regeneration in dystrophic or injured skeletal muscle via the transplantation of muscle-derived stem cells.