Chibby and Wnt Signaling in Ciliated Cell Differentiation

描述（由申请人提供）：呼吸道中有大量活动纤毛，它们以波浪状同步跳动，将吸入的碎屑和粘液中的病原体推进到咽部。这提供了对抗呼吸道感染的重要先天防御机制。运动纤毛通常在呼吸道上皮纤毛细胞的顶面上以100至300个簇的形式存在。纤毛运动障碍与人类疾病，特别是原发性纤毛运动障碍（PCD）有关。尽管它们的临床重要性，很少有人知道的关键分子和信号通路，支配运动纤毛和纤毛细胞分化。因此，了解这些基本的生物学现象对于开发用于预防和治疗PCD和其他纤毛相关疾病的新型治疗策略至关重要。Chibby（Cby）最初是作为Wnt/β-连环蛋白信号通路的进化上保守的拮抗剂分离的。Cby与关键的下游共激活因子<$-连环蛋白物理相互作用并抑制<$-连环蛋白介导的转录激活。有趣的是，Cby敲除（Cby-/-）小鼠由于完全缺乏粘膜纤毛转运活性而患有反复呼吸道感染，这让人联想到PCD。我们的研究进一步揭示了Cby-/-小鼠鼻和肺上皮中的纤毛细胞分化差，其特征在于运动纤毛的数量显著减少。与这种表型一致，我们发现内源性Cby蛋白定位于纤毛的基部。因此，我们的研究结果表明，Cby在呼吸道运动纤毛的正确形成/功能中起着至关重要的作用。然而，Cby-/-小鼠纤毛缺陷的细胞和分子基础仍然在很大程度上未被探索。此外，Cby的纤毛发生功能是否与Wnt/β-catenin信号传导有关尚不清楚。本研究的目的是阐明Cby、Cby相互作用蛋白和Wnt/<$-catenin信号在运动纤毛发生和气管纤毛细胞分化中的作用。为了实现这一目标，我们提出以下具体目标：具体目标1。探讨Cby在气管纤毛细胞分化中的作用;特异性目的2.检查气管纤毛细胞分化过程中Cby基因的转录调控;特异性目的3。分离Cby结合伴侣并确定其在纤毛细胞分化中的作用。我们希望这些实验将有助于从根本上了解纤毛发生和纤毛细胞分化的分子和细胞机制。

DESCRIPTION (provided by applicant): Motile cilia are abundant in our respiratory tract, and beat synchronously in waves to propel inhaled debris and pathogens entrapped in mucus to the pharynx. This provides an important innate defense mechanism against respiratory infections. Motile cilia are usually found as clusters of 100 to 300 on the apical surface of a ciliated cell in the respiratory epithelium. Dysfunction of motile cilia has been linked to human diseases, especially primary ciliary dyskinesia (PCD). Despite their clinical importance, little is known about the key molecules and signaling pathways that govern motile ciliogenesis and ciliated cell differentiation. Therefore, understanding these fundamental biological phenomena is crucial for developing novel therapeutic strategies for the prevention and treatment of PCD and other cilia-related disorders. Chibby (Cby) was originally isolated as an evolutionarily conserved antagonist of the Wnt/¿-catenin signaling pathway. Cby physically interacts with the pivotal downstream coactivator ¿-catenin and inhibits ¿-catenin-mediated transcriptional activation. Intriguingly, Cby-knockout (Cby-/-) mice suffer from recurrent respiratory infections due to a complete absence of mucociliary transport activity, reminiscent of PCD. Our studies further revealed that ciliated cells in the nasal and lung epithelia of Cby-/- mice are poorly differentiated characterized by a markedly decreased number of motile cilia. Consistent with this phenotype, we found that endogenous Cby protein localizes to the base of cilia. Our findings therefore establish that Cby plays an essential role in proper formation/function of motile cilia in the respiratory tract. However, the cellular and molecular bases underlying the ciliary defects of Cby-/- mice remain largely unexplored. In addition, whether the ciliogenic function of Cby relates to Wnt/¿-catenin signaling is unclear. The goal of this proposal is to elucidate the roles of Cby, Cby-interacting proteins and Wnt/ ¿-catenin signaling in motile ciliogenesis and tracheal ciliated cell differentiation. In order to achieve this goal, we propose the following Specific Aims: Specific Aim 1. Investigate the role of Cby in tracheal ciliated cell differentiation; Specific Aim 2. Examine transcriptional regulation of the Cby gene during differentiation of tracheal ciliated cells; Specific Aim 3. Isolate Cby-binding partners and define their roles in ciliated cell differentiation. We expect that these experiments will contribute to a fundamental understanding of the molecular and cellular mechanisms of ciliogenesis and ciliated cell differentiation.