Investigation of Sulf regulation on the noncanonical Wnt signaling pathway

描述（由申请人提供）：肌肉再生是一个复杂的过程，涉及多个因素，这些因素在空间和时间上决定骨骼肌干细胞（称为卫星细胞（SC））的激活、增殖、迁移和分化，以及新生成肌细胞（分化SC）的融合。因此，了解参与肌肉再生每个阶段的调节因素将为设计更好的治疗肌肉相关疾病（如肌肉萎缩症和肌肉萎缩症）开辟新的领域。我们之前的研究表明，硫酸肝素-6- o -硫内酯酶（Sulfs）的缺失会导致肌肉再生的延迟和SC群体的短暂增加，这种表型可能是由SC分化过程中硫介导的FGF2信号抑制引起的。硫酸盐在骨骼肌再生过程中是否起着额外的作用尚不清楚。这里的初步研究表明，硫在肌肉再生和卫星细胞培养过程中抑制非规范的Wnt信号通路。由于非规范Wnt信号被证明通过驱动对称细胞分裂来促进SC的扩张，我们假设Sulfs调节非规范Wnt信号来影响肌肉再生过程中的SC群体。我们的研究结果有望为骨骼肌再生和退行性疾病期间调节肌肉发生和SC保存的基质依赖机制提供依据。本研究结果可为今后硫酸肝素及其衍生物在干细胞工程和肌肉退行性疾病治疗中的应用奠定基础。为了研究这一假设，我们将利用体外细胞模型（单个肌纤维）和动物模型的结合，在卫星细胞Pax7Sulf-DN （Pax7-Cre:ER/Rosa26;eYFP/Sulf1/2flox）和Pax7Sulf-DN中，通过损伤和肌肉萎缩进行再生。分别mdx。我们还将利用表达显性阴性硫代硫的慢病毒来急性灭活硫代硫。

DESCRIPTION (provided by applicant): Muscle regeneration is an intricate process involving multiple factors that spatially and temporally dictate the activation, proliferation, migration, and differentiation of skeletal muscle stem cells known as satellite cells (SC) and the fusion of nascent myoblasts (differentiated SC). Understanding the regulatory factors participating in each individual stage of muscle regeneration would therefore open new venues for designing better treatments for muscle related diseases such as muscular dystrophy and atrophy. Our previous study has shown that loss of heparan sulfate-6-O-endosulfatases (Sulfs) leads to a delay in muscle regeneration and a transient increase in SC population, and such phenotypes may be caused by Sulf-mediated repression of FGF2 signaling during SC differentiation. Whether Sulfs play additional roles during skeletal muscle regeneration is unknown. Here preliminary studies show that Sulfs repress the noncanonical Wnt signaling pathway during muscle regeneration and in satellite cell cultures. Since noncanonical Wnt signaling is shown to promote SC expansion by driving the symmetric cell division, we hypothesize that Sulfs regulate the noncanonical Wnt signaling to affect SC population during muscle regeneration. Results of our studies are expected to provide matrix-dependent mechanisms that regulate myogenesis and SC preservation during skeletal muscle regeneration and degenerative diseases. These findings may provide basis for future application of heparan sulfate (HS) and HS-derivatives in stem cell engineering and treatment of muscular degenerative diseases. To investigate such hypothesis, we will utilize a combination of in vitro cell model (single myofibers) and animal models of regeneration by injury and by muscular dystrophy in mice having Sulfs specifically inactivated in the satellite cells Pax7Sulf-DN (Pax7-Cre:ER/Rosa26;eYFP/Sulf1/2flox) and Pax7Sulf-DN;mdx, respectively. We will also utilize lentivirus expressing the dominant negative Sulf2 to acutely inactivate Sulfs. PUBLIC HEALTH RELEVANCE: The following studies will be conducted to investigate the regulatory roles of Sulfs on satellite cell expansion and the mechanisms underlying Sulf regulation on the noncanonical Wnt signaling pathway. Information derived from this study would open new venues for designing better treatments for muscle related diseases such as muscular dystrophy and atrophy.