Delineating the Function of TDP-43 in Skeletal Muscle Formation

项目摘要/摘要 许多退行性神经肌肉疾病与细胞内蛋白质的堆积有关。 集合体。这些聚集体被广泛认为会导致疾病，因此被认为对 手机。最近，我们发现了类似的聚集体，称为肌颗粒，在健康的再生和 分化的骨骼肌。Myo颗粒含有RNA和RNA结合蛋白。一种著名的RNA- 在肌颗粒中发现的结合蛋白tdp-43，由于其存在于聚集体中而特别令人感兴趣。 在退行性疾病中观察到的。此外，肌颗粒定位于发育中的肌节，并包含一个 携带TDP-43结合位点的大量肌节mRNAs。随着肌肉再生和肌节的形成 被取代，肌颗粒被清除，TDP-43重新定位到细胞核。总而言之，这些发现表明 TDP-43可能在促进肌节形成和TDP-43积聚方面发挥作用，该TDP-43含有- 疾病中发现的聚集体可能不是原因，而是骨骼反复尝试的结果 再生。在预审工作中，我发现肌肉干细胞中TDP-43的缺失阻碍了分化， 确定TDP-43在骨骼肌中的重要作用。具体目标1将评估TDP-43在 肌纤维在再生过程中的形成和成熟。为此，我将在以下位置删除TDP-43 分化细胞融合和再生肌肉成熟的再生检查点。这个 目标1的结果将用于特定目标2的实验，在那里我将分析TDP的作用- 肌节形成43例。在前期工作中，TDP-43在再生过程中分化细胞中的缺失 导致肌肉修复不当，肌纤维大小急剧减小。此外，肌纤维 当TDP-43缺失时，成熟度降低，这表明发育的 肌节蛋白。因此，肌节的再生和修复需要TDP-43吗？我会问这个问题 通过采用体内方法，TDP-43将在健康和再生肌肉中被删除，以 评估对肌节形成、成熟和降解的影响。TDP-43的功能定位 肌节的形成有助于更好地理解肌球和肌球之间的关系 与疾病相关的TDP-43聚集体。

PROJECT ABSTRACT/SUMMARY Many degenerative neuromuscular diseases are associated with cytoplasmic accumulation of protein aggregates. These aggregates are widely considered to contribute disease and thus are thought to be toxic to the cell. Recently, we discovered similar aggregates, termed myo-granules, in healthy regenerating and differentiating skeletal muscle. Myo-granules contain RNA and RNA-binding proteins. One prominent RNA- binding protein found in myo-granules, TDP-43, is of particular interest due to its presence in aggregates observed in degenerative disease. Further, myo-granules localize to developing sarcomeres and contain an abundance of sarcomeric mRNAs that bear TDP-43 binding-sites. As the muscle regenerates and sarcomeres are replaced, myo-granules are cleared and TDP-43 re-localizes to the nuclei. Together, these findings suggest that TDP-43 may play a role in facilitating sarcomere formation and that accumulation of TDP-43 containing- aggregates found in disease may not be the cause but instead the result of recurring attempts at skeletal regeneration. In pre-liminary work, I found that TDP-43 deletion in muscle stem cells prevents differentiation, identifying an essential role for TDP-43 in skeletal muscle. Specific Aim 1 will evaluate the role of TDP-43 in myofiber formation and maturation during regeneration. To accomplish this, I will delete TDP-43 at regenerative checkpoints for fusion of differentiated cells and for maturation of the regenerating muscle. The results from aim 1 will be used to inform experiments in Specific Aim 2 where I will analyze the role of TDP- 43 in sarcomere formation. In pre-liminary work, TDP-43 deletion in differentiating cells during regeneration results in muscle that is improperly repaired and myofiber size is drastically reduced. Additionally, myofiber maturation is reduced when TDP-43 is deleted as indicated by the continued expression of developmental sarcomeric proteins. Thus, is TDP-43 required for sarcomere regeneration and repair? I will ask this question by taking an in vivo approach where TDP-43 will be deleted in both healthy and regenerating muscle to evaluate the effect on sarcomere formation, maturation, and degradation. Delineating the function of TDP-43 in sarcomere formation should lead to a better understanding of the relationship between myo-granules and disease-associated TDP-43 aggregates.