β-catenin通过α2NKA调控骨骼肌功能的作用及其机制研究

β-catenin is a key component of the canonical Wnt signaling pathway.It has been shown to play a role in the formation of the neuromuscular junction (NMJ). The underlying mechanisms are not yet elucidated. Our previous studies showed that in the absence of muscle β-catenin, the resting membrane potential (RMP) depolarized in skeletal muscle cells. The levels of protein expression and transcriptional activity of α2NKA were reduced with β-catenin deficiency. Because β-catenin plays an important role in regulating gene transcription, and α2NKA is in close relationship with the function of the skeletal muscles. β-catenin is likely to regulate skeletal muscles via the α2NKA. HSA-β-cat-/- mice and cultured C2C12 cells were designed for RNAi, overexpress, Whole cell clamp recording and contractility detection. And then we investigate whether the RMP, AP, current of α1NKA and α2NKA, contractility and fatigability of skeletal muscles changed, when β-catenin knocked down or overexpressed. Futhermore, we used CoIP, immunofluorescence, α2NKA overexpression and dn-TCF or β-catenin-AA transfection to study the interaction between β-catenin and α2NKA. Our research will suggest a possible underlying mechanism and provide additional evidence for the diagnosis and treatment of NMJ related disease.

β-catenin 是经典Wnt信号通路的下游分子，能调控神经肌肉接头的功能，但其机制尚未阐明。我们发现骨骼肌β-catenin表达缺失导致细胞发生去极化，并伴α2NKA表达下降及转录减少。由于β-catenin能调控基因转录、α2NKA又与骨骼肌细胞功能密切相关，β-catenin可能通过调控后者来实现对骨骼肌功能的调节。因此，本项目拟采用条件性敲除小鼠及培养的C2C12细胞，通过RNAi、过表达、全细胞记录及骨骼肌收缩力检测等方法，探讨骨骼肌β-catenin对骨骼肌细胞静息膜电位、动作电位、α2NKA电流、收缩力及易疲劳性等的作用；另一方面通过免疫共沉淀、过表达α2NKA、转染dn-TCF或β-catenin-AA、免疫荧光等方法，发现β-catenin与α2NKA之间的关系，旨在阐明骨骼肌β-catenin调节骨骼肌相关生理功能的分子机制，为神经肌肉接头相关疾病的诊治提供新思路。