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

Abstract

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 interactions. 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 <i>Runx2</i> in CNC-derivatives results in reduced expression of perimysial markers (<i>Aldh1a2</i> and <i>Hic1</i>) as well as soft palate muscle defects in <i>Osr2-Cre;Runx2^fl/fl</i> mice. We further reveal that Runx2 maintains perimysial marker expression through suppressing <i>Twist1,</i> and that myogenesis is restored in <i>Osr2-Cre;Runx2^fl/fl;Twist1^fl/+</i> 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.