Single cell RNA sequencing analyis of periodontal ligament derived from Mkx deficient rat

The periodontal ligament (PDL) is a fibrous tissue that connects alveolar bone to the cementum that covers teeth. The periodontal ligament comprises fibroblasts, osteoblasts, blood vessels, nerves, epithelial cells, and a rich extracellular matrix (ECM). The ECM of the PDL includes principal fibers that comprise mainly type 1 and type 3 collagen, and oxytalan fibers that consist of elastic fibers, proteoglycans, and glycosaminoglycans that are mainly produced by periodontal ligament fibroblasts The transcription factor mohawk homeobox (Mkx) is expressed in the PDL where it plays an important role in the development and maintenance of the PDL. We previously showed that Mkx-deficient mice and rats have hypoplastic Achilles tendons with endochondral ossification. In addition, Mice deficient in Mkx develop an age-related reduction in PDL fibers and increased ossification, indicating that Mkx plays an important role in PDL homeostasis (Koda et al., 2017). However, the precise and critical functions of Mkx in the cell populations comprising PDL have not yet been elucidated. In this study, we performed single-cell RNA sequencing to clarify the effects of a Mkx deficiency on PDL cellular heterogeneity and differences between gene expression in PDL.