Gene‐expression analysis of cementoblasts and osteoblasts

Abstract

Objective The purpose of this study was to assess differences in gene expression between cementoblasts and osteoblasts using gene profiling of cell populations isolated directly from osteocalcin-GFP transgenic mice. Background Cementum and bone are similar mineralized tissues, but cementum accumulates much more slowly, does not have vasculature or innervation or undergo remodeling. Despite these differences, there are no well-established markers to distinguish cementoblasts from other mature mineralizing cells such as osteoblasts and odontoblasts. Methods Osteocalcin-GFP (OC-GFP) reporter mice were used as they show labeling of cementoblasts, osteoblasts and odontoblasts, but not periodontal ligament fibroblasts, within the periodontium. We sorted cells digested from the molar root surface to isolate OC-GFP+ cementoblasts. Osteoblasts were isolated from calvarial digests. Microarray analysis was performed, and selected results were confirmed by real time PCR and immunostaining or in situ hybridization. Results Microarray analysis identified 95 genes that were expressed at least 2-fold higher in cementoblasts than osteoblasts. Our analysis indicated that the Wnt signaling pathway was differentially regulated, as were genes related to skeletal development. Real time PCR confirmed that expression of Wnt inhibitors Wif1 and Sfrp1 was elevated in cementoblasts compared to osteoblasts, and Wif1 expression was localized to the apical root region. In addition, the transcription factor Barx1 was expressed at higher levels in cementoblasts, and immunohistochemistry indicated that BARX1 expression was detectable in apical cementoblasts and cementocytes, but was not present in osteoblasts or odontoblasts. Conclusion The OC-GFP mouse provides a good model for selectively isolating cementoblasts, and allowed for identification of differentially expressed genes between cementoblasts and osteoblasts.

ceRNA Network Development and Tumour-infiltrating Immune Cell Analysis in Metastatic Breast Cancer of Bone

“…Recently, several studies have shown the participation of Wnt6, Barx1, ptprz1, and other genes in the regulation of Wnt/β-catenin signalling and their involvement in the development of malignant tumours [31][32][33][34][35][36][37][38][39][40][41]. These ndings support our hypothesis that dlx6-as1 may affect the mRNA expression of Wnt6, Barx1, ptprz1 and other genes through ceRNA network to regulate Wnt/β-catenin signalling and participate in the distant bone metastasis of breast cancer.…”

“…Wnt/β-catenin signalling is critical in numerous cellular processes such as proliferation, invasion, and migration [31]. The involvement of Wnt/β-catenin signalling has been demonstrated in several malignant tumours including breast cancer and Wnt/βcatenin activation promotes tumour cell growth and metastasis [31,32]. Previous studies have shown that Wnt activation inhibits memory T cells by reducing key transcription factors produced by these cells [33].…”

Visual reporters for study of the osteoblast lineage

“…Oc-GFP has also been used to isolate cementoblasts, as it is expressed in cementoblasts, cementocytes and odontoblasts but not PDL cells. [47]…”

SIRT6 overexpression inhibits cementogenesis by suppressing glucose transporter 1

“…Studies of mouse genetics and human disease phenotypes indicate that cementum and bone share regulatory pathways and key developmental influences (Bosshardt, ; Foster et al, ). In contrast to bone, cementum accumulates more slowly, contains no vasculature, and undergoes no remodeling (Matthews et al, ). Cementoblasts, which form cementum, are differentiated from progenitor cells in periodontal ligaments and resemble osteoblasts (J. Liao et al, ).…”