Runx2-Twist1 interaction coordinates cranial neural crest guidance of soft palate myogenesis

Cranial neural crest (CNC) cells give rise to bone, cartilage, tendons, and ligaments of the vertebrate craniofacial musculoskeletal complex, as well as regulate mesoderm-derived craniofacial muscle development through cell-cell interaction. Using the mouse soft palate as a model, we performed an unbiased single-cell RNA-seq analysis to investigate the heterogeneity and lineage commitment of CNC derivatives during craniofacial muscle development. We show that Runx2, a known osteogenic regulator, is expressed in the CNC-derived perimysial and progenitor populations. Loss of Runx2 in CNC-derivatives results in reduced expression of perimysial markers (Aldh1a2 and Hic1) as well as soft palate muscle defects in Osr2-KICre;Runx2fl/fl mice. We further reveal that Runx2 maintains perimysial marker expression through suppressing Twist1, and that myogenesis is restored in Osr2-KICre;Runx2fl/fl;Twist1fl/+ mice. Collectively, our findings highlight the roles of Runx2, Twist1, and their interaction in regulating the fate of CNC-derived cells as they guide craniofacial muscle development through cell-cell interactions.

颅神经嵴（Cranial neural crest, CNC）细胞分化形成脊椎动物颅面肌肉骨骼复合体的骨、软骨、肌腱和韧带，并通过细胞间相互作用调控中胚层来源的颅面肌肉发育。我们以小鼠软腭为模型，开展无偏倚单细胞RNA测序分析，旨在探究颅面肌肉发育过程中CNC衍生细胞的异质性与谱系定向。研究发现，已知成骨调控因子Runx2在CNC衍生的肌周细胞及祖细胞群中表达。CNC衍生细胞中Runx2缺失导致肌周细胞标志物（Aldh1a2和Hic1）表达降低，且Osr2-KICre;Runx2fl/fl小鼠出现软腭肌肉缺陷。我们进一步发现，Runx2通过抑制Twist1维持肌周细胞标志物的表达，且Osr2-KICre;Runx2fl/fl;Twist1fl/+小鼠的肌生成得以恢复。综上，我们的研究揭示了Runx2、Twist1及其相互作用在调控CNC衍生细胞命运中的作用，这些细胞通过细胞间相互作用引导颅面肌肉发育。