Trio cooperates with Myh9 to regulate neural crest-derived craniofacial development.
Trio cooperates with Myh9 to regulate neural crest-derived craniofacial development.
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Trio 与 Myh9 合作调节神经嵴源性颅面发育
作者：
Guo S;Meng L;Liu H;Yuan L;Zhao N;Ni J;Zhang Y;Ben J;Li YP;Ma J
Trio是Rho-GEF家族的独特成员，具有三个催化结构域，对生理和发育环境中的各种细胞过程至关重要。人类的TRIO突变涉及颅面异常，其中患者表现为下颌骨修复。然而，关于Trio在神经嵴细胞（NCC）衍生的颅面发育中的分子机制知之甚少，并且仍然缺乏直接证据来指定Trio在NCC诱导的颅面异常中的功能作用。研究方法：在体内，我们使用斑马鱼和NCC特异性基因敲除小鼠模型来研究Trio morphants中NCC发育的表型和动力学。在体外，使用iTRAQ、GST pull-down测定和邻近连接测定（PLA）来探索Trio及其潜在下游介质在NCC迁移和分化中的作用。结果如下：在斑马鱼和小鼠模型中，Trio的破坏引起迁移缺陷并损害NCC衍生物的分化，导致颅面生长缺陷和下颌骨修复。此外，Trio正调控Myh 9表达，并直接与Myh 9相互作用，共同调节NCC中的下游细胞信号传导。我们进一步证明，Trio或Myh 9的破坏抑制了Rac 1和Cdc 42的活性，特别是影响β-catenin的核输出和NCC极化。值得注意的是，在斑马鱼中由三重缺陷引起的颅面异常可以通过注射编码myh 9，ca-Rac 1或ca-Cdc 42的mRNA来部分挽救。结论：在这里，我们确定了Trio，主要与Myh 9相互作用，在颅面发育过程中作为NCC迁移和分化的关键调节因子。我们的研究结果表明，三重变形斑马鱼和Wnt 1-cre;Triofl/fl小鼠提供了潜在的模型系统，以促进三重突变导致颅面异常的致病机制的研究。
Trio is a unique member of the Rho-GEF family that has three catalytic domains and is vital for various cellular processes in both physiological and developmental settings. TRIO mutations in humans are involved in craniofacial abnormalities, in which patients present with mandibular retrusion. However, little is known about the molecular mechanisms of Trio in neural crest cell (NCC)-derived craniofacial development, and there is still a lack of direct evidence to assign a functional role to Trio in NCC-induced craniofacial abnormalities. Methods: In vivo, we used zebrafish and NCC-specific knockout mouse models to investigate the phenotype and dynamics of NCC development in Trio morphants. In vitro, iTRAQ, GST pull-down assays, and proximity ligation assay (PLA) were used to explore the role of Trio and its potential downstream mediators in NCC migration and differentiation. Results: In zebrafish and mouse models, disruption of Trio elicited a migration deficit and impaired the differentiation of NCC derivatives, leading to craniofacial growth deficiency and mandibular retrusion. Moreover, Trio positively regulated Myh9 expression and directly interacted with Myh9 to coregulate downstream cellular signaling in NCCs. We further demonstrated that disruption of Trio or Myh9 inhibited Rac1 and Cdc42 activity, specifically affecting the nuclear export of β-catenin and NCC polarization. Remarkably, craniofacial abnormalities caused by trio deficiency in zebrafish could be partially rescued by the injection of mRNA encoding myh9, ca-Rac1, or ca-Cdc42. Conclusions: Here, we identified that Trio, interacting mostly with Myh9, acts as a key regulator of NCC migration and differentiation during craniofacial development. Our results indicate that trio morphant zebrafish and Wnt1-cre;Triofl/fl mice offer potential model systems to facilitate the study of the pathogenic mechanisms of Trio mutations causing craniofacial abnormalities.