P2: MYOGENIC POTENTIAL OF BONE MARROW CELLS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 绿色荧光蛋白(GFP)阳性的骨髓细胞向骨骼肌细胞的转化已被证明，这是该项目的重点。我们已经确定，供体GFP+骨髓细胞通过将GFP和结蛋白共定位于具有形态特征的肌肉纤维中而转化为肌肉细胞。我们发现，通过改变移植方案的具体情况，包括细胞数量、移植时机和细胞输送方式(即局部注射与全身输注或动员移植细胞)，骨髓转化或向骨骼肌细胞转分化的水平越来越高。我们还发现，转换事件的数量随着不同的动员方案而变化，并且骨髓细胞亚群比未分离的骨髓细胞具有更高的转化率。骨骼肌损伤的性质，辐射或直接注射心脏毒素，也是决定体内看到的骨髓向肌肉细胞转分化水平的关键。在使用心脏毒素对小鼠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，我们获得了高达12%的转化率，即12%的肌肉纤维是GFP+的骨骼肌细胞。该项目评估将导致高水平的骨髓转化为肌肉的肌肉损伤的特殊性，并探索哪种特定的细胞类型可以以最高的频率产生肌肉，适合于这种转化的移植时机以及获得显著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.