Osteogenic and angiogenic profiles of the palatal process of the maxilla and the palatal process of the palatine bone

Abstract

Hard palate consists anteriorly of the palatal process of the maxilla (ppmx) and posteriorly of the palatal process of the palatine (ppp). Currently, palatal osteogenesis is receiving increasing attention. This is the first study to provide an overview of the osteogenesis process of the mouse hard palate. We found that the period in which avascular mesenchymal condensation becomes a vascularized bone structure corresponds to embryonic day (E) 14.5 to E16.5 in the hard palate. The ppmx and ppp differ remarkably in morphology and molecular respects during osteogenesis. Osteoclasts in the ppmx and ppp are heterogeneous. There was a multinucleated giant osteoclast on the bone surface at the lateral‐nasal side of the ppmx, while osteoclasts in the ppp were more abundant and adjacent to blood vessels but were smaller and had fewer nuclei. In addition, bone remodeling in the hard palate was asymmetric and exclusively occurred on the nasal side of the hard palate at E18.5. During angiogenesis, CD31‐positive endothelial cells were initially localized in the surrounding of palatal mesenchymal condensation and then invaded the condensation in a sprouting fashion. At the transcriptome level, we found 78 differentially expressed genes related to osteogenesis and angiogenesis between the ppmx and ppp. Fifty‐five related genes were up/downregulated from E14.5 to E16.5. Here, we described the morphogenesis and the heterogeneity in the osteogenic and angiogenic genes profiles of the ppmx and ppp, which are significant for subsequent studies of normal and abnormal subjects.

Embryonic inhibition of colony‐stimulating factor 1 receptor induces enlarged cartilaginous zone of the midpalatal suture in postnatal mice

“…In our previous study, TRAP-positive osteoclasts were first reported at PPMXA, PPMXP and PPP at E18.5, E17.5 and E16.5, respectively. 6 Investigating the spatiotemporal expression of CSF1R in the embryonic palate, we found that CSF1R was significantly upregulated at E16.5, E15.5 and E14.5 in PPMXA, PPMXP and PPP, respectively. Remarkably, these time points coincided with the initial two days when TRAP-positive osteoclasts were detectable (data pending publication).…”

“…[4] Our previous study first described TRAP-positive osteoclasts detected at the embryonic palatal bone. 6 Studies of embryonic osteoclasts have focused on long bones, and to the best of our knowledge, only Kawata T has thus far described osteoporotic (op/op) mice exhibiting immature fusion of the midpalatal suture due to a reduction in osteoclasts without further detailed investigations. 7 Subsequently, a Csf1 inactivating mutation was found in these mice, which are now termed Csf1op/op mice.…”

“…The interactions between osteoclasts and osteoblasts are crucial for normal bone development and remodelling. [4] Our previous study first described TRAP‐positive osteoclasts detected at the embryonic palatal bone 6 . Studies of embryonic osteoclasts have focused on long bones, and to the best of our knowledge, only Kawata T has thus far described osteoporotic (op/op) mice exhibiting immature fusion of the midpalatal suture due to a reduction in osteoclasts without further detailed investigations 7 .…”

Influence of Scaffold Microarchitecture on Angiogenesis and Regulation of Cell Differentiation during the Early Phase of Bone Healing: A Transcriptomics and Histological Analysis

“…Since scaffold porosity and microporosity are the same for both scaffolds, a lower O 2 -concentration in Fil050G samples appears unlikely and additional factors might have induced EREG expression. Moreover, NR4A1 and FGF18 , also upregulated in Fil050G samples, have links to angiogenesis/osteogenesis-related factors [ 53 , 54 , 55 ]. Furthermore, ACVRL1 , C-type lectin domain family 14 member A ( CLEC14A ) [ 56 ], and Nitric oxide synthase endothelial ( NOS3 ) [ 57 ] possess angiogenic/vasculogenic potential within the bone healing process [ 58 ].…”

Osteoclast differentiation and dynamic mRNA expression during mice embryonic palatal bone development

“…In these studies, distinct gene expression patterns along the antero-posterior axis of the secondary palate were generally recognized. For further research, we described morphogenesis and heterogeneity in the osteogenic and angiogenic gene profiles of the PPMX and PPP in a previous study 9 .…”