Leveraging Spatial Transcriptomics to Decode Craniofacial Development.

Understanding how intricate cellular networks and signaling pathways communicate during the formation of craniofacial tissues like the palate and tooth has been the subject of intense investigation for several decades. Both organ systems undergo patterning morphogenesis and the subsequent terminal differentiation of matrix-producing cells that form biomineralized matrices like bone, enamel, dentin, and cementum. Until recently, gene expression profiles could only be assessed for a select number of cells without the context of the entire milieu of genes expressed by neighboring cells and tissues. Today, the cutting-edge field of spatial transcriptomics offers a remarkable suite of innovative technologies of multiplex gene analyses and imaging that can assess the expression of a vast library of genes that are present in situ during normal and abnormal conditions. In this review, we summarize some key technologies which have in recent years enabled an unprecedented breadth and depth of transcriptomic analyses in craniofacial development. We focus in detail on select methods that our research group has applied to better understand the cellular and molecular events that drive palate and tooth development. Our overall goal is to unravel the complexities of these unique biological systems to provide meaningful biological insights into the cellular and molecular events that drive normal development. As a work-in-progress, we strive for a deeper understanding of the temporal and spatial gene expression profiles within cells and tissues during normal and abnormal palate and tooth development. Such knowledge provides the framework for further studies that can characterize the function of new or novel genes that have the potential of serving as therapeutic targets for correcting disorders like cleft palate and tooth agenesis.