P2: MYOGENIC POTENTIAL OF BONE MARROW CELLS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 绿色荧光蛋白（GFP）阳性骨髓细胞转化为骨骼肌细胞已被证明，是这个项目的重点。我们已经确定，供体GFP+骨髓细胞已转化为肌细胞共定位的GFP和结蛋白在形态特征的肌纤维。我们已经发现，通过改变移植方案的细节，包括细胞数量、移植时间和细胞递送模式（即局部注射vs全身输注或移植细胞的动员），骨髓转化或转分化为骨骼肌细胞的水平增加。我们还发现，转换事件的数量随着不同的动员方案而变化，并且骨髓细胞的亚群比未分离的骨髓细胞具有更高的转换率。骨骼肌损伤、辐射或直接心脏毒素注射的性质在确定体内骨髓向肌细胞转分化的水平方面也是至关重要的。 在先前移植的小鼠中使用心脏毒素肌肉损伤的初步研究中，结合辐射和直接注射不同群体的骨髓细胞，我们已经获得了高达12%的转化率，即12%的肌纤维是GFP+骨骼肌细胞。该项目评估了肌肉损伤的具体情况，这将导致骨髓向肌肉的高水平转化，并探索哪种特定的细胞类型可以以最高频率产生肌肉，适合这种转化的移植时机以及获得显着肌肉转化所需的细胞数量。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Conversion of green-fluorescent protein (GFP) positive marrow cells to skeletal muscle cells has been demonstrated and is the focus of this project. We have determined that donor GFP+ marrow cells have converted to muscle cells by colocalizing GFP and desmin in morphologically characteristic muscle fibers. We have found increasing levels of marrow conversion or transdifferentiation to skeletal muscle cells by altering the specifics of the transplant regimen including cell number, timing of transplant and mode of cell delivery (i.e. local injection vs systemic infusion or mobilization of transplanted cells). We have also found that the number of conversion events changes with different mobilization regimens and that subsets of marrow cells, give higher rates of conversion than unseparated marrow cells. The nature of the skeletal muscle injury, radiation or direct cardiotoxin injection, is also critical in determining the level of transdifferentiation of marrow to muscle cells seen in vivo. In preliminary studies using a cardiotoxin muscle injury in previously transplanted mice, combined with radiation and direct injection of different populations of marrow cells we have obtained conversion rates up to12%, i.e. 12% of the muscle fibers were GFP+ skeletal muscle cells. This project evaluates the specifics of muscle injury which will lead to high-level conversion of marrow to muscle and to explore which particular cell type can give rise to muscle at the highest frequency, the timing of transplant suitable for such conversions and the number of cells necessary to obtain significant muscle conversion.