Integrated Transcriptome and Network Analysis Reveals Spatiotemporal Dynamics of Calvarial Suturogenesis

SUMMARY

Craniofacial abnormalities often involve sutures, the growth centers of the skull. To characterize the organization and processes governing their development, we profile the murine frontal suture, a model for sutural growth and fusion, at the tissue- and single-cell level on embryonic days (E)16.5 and E18.5. For the wild-type suture, bulk RNA sequencing (RNA-seq) analysis identifies mesenchyme-, osteogenic front-, and stage-enriched genes and biological processes, as well as alternative splicing events modifying the extracellular matrix. Single-cell RNA-seq analysis distinguishes multiple subpopulations, of which five define a mesenchymeosteoblast differentiation trajectory and show variation along the anteroposterior axis. Similar analyses of in vivo mouse models of impaired frontal suturogenesis in Saethre-Chotzen and Apert syndromes, Twist1 ^+/− and Fgfr2 ^+/S252W , demonstrate distinct transcriptional changes involving angiogenesis and ribogenesis, respectively. Co-expression network analysis reveals gene expression modules from which we validate key driver genes regulating osteoblast differentiation. Our study provides a global approach to gain insights into suturogenesis.

Graphical Abstract

In Brief

Calvarial suture dysgenesis is a significant human pathology. Holmeset al. transcriptionally profile the frontal suture in normal mice and mouse models of frontal suture dysgenesis at multiple embryonic ages using bulk and single-cell RNA-seq. This comprehensive dataset allows high-resolution exploration of suture development at the transcriptional and subpopulation levels.