CCN3 and DLL1 co-regulate osteogenic differentiation of mouse embryonic fibroblasts in a Hey1-dependent manner

Abstract

Notch signaling pathway is one of the most important pathways to regulate intercellular signal transduction and is crucial in the regulation of bone regeneration. Nephroblastoma overexpressed (NOV or CCN3) serves as a non-canonical secreted ligand of Notch signaling pathway and its role in the process of osteogenic differentiation of mesenchymal stem cells (MSCs) was undefined. Here we conducted a comprehensive study on this issue. In vivo and in vitro studies have shown that CCN3 significantly inhibited the early and late osteogenic differentiation of mouse embryonic fibroblasts (MEFs), the expression of osteogenesis-related factors, and the subcutaneous ectopic osteogenesis of MEFs in nude mice. In mechanism studies, we found that CCN3 significantly inhibited the expression of BMP9 and the activation of BMP/Smad and BMP/MAPK signaling pathways. There was also a mutual inhibition between CCN3 and DLL1, one of the classic membrane protein ligands of Notch signaling pathway. Additionally, we further found that Hey1, the target gene shared by BMP and Notch signaling pathways, partially reversed the inhibitory effect of CCN3 on osteoblastic differentiation of MEFs. In summary, our findings suggested that CCN3 significantly inhibited the osteogenic differentiation of MEFs. The inhibitory effect of CCN3 was mainly through the inhibition of BMP signaling and the mutual inhibition with DLL1, so as to inhibit the expression of Hey1, the target gene shared by BMP and Notch signaling pathways.

RETRACTED ARTICLE: Schnurri-3 regulates BMP9-induced osteogenic differentiation and angiogenesis of human amniotic mesenchymal stem cells through Runx2 and VEGF

“…In a recent study, we reported that BMP9 (also termed as growth differentiation factor 2) is one of the most potent BMPs among the 14 types of BMPs in the induction of osteogenic differentiation 19,56 . BMP9 usually produces its marked effect through the BMP/Smad signaling pathway, which includes the canonical BMP/Smad pathway or the non-canonical BMP/ Smad pathways, such as ERK and p38 MAPK pathway 57 . In the canonical BMP/Smad pathway, BMP9 activates the corresponding phosphorylated R-Smad (named Smad1/5/ 8), and the phosphorylated Smad1/5/8 (p-Smad1/5/8) recruits and phosphorylates Smad4 to form the complex.…”

Bone morphogenetic protein 9 enhances osteogenic and angiogenic responses of human amniotic mesenchymal stem cells cocultured with umbilical vein endothelial cells through the PI3K/AKT/m-TOR signaling pathway

“…This may suggest that BMP9 is in possession of the regulatory function of vascularization in MSCs and endothelial cells. BMP9 works its function through BMP/Smad signaling, including p38-MAPK and ERK1/2-MAPK pathway [ 50 – 52 ]. For the canonical BMP signaling pathway, which activates the R-Smad named phosphorylated Smad1/5/8 (p-Smad1/5/8) through binding with its membrane receptor, and then forming a complex with the phosphorylated Smad 4.…”

Molecular and Genetic Interactions between CCN2 and CCN3 behind Their Yin–Yang Collaboration

“…However, the effects of CCN3 on osteogenesis are particularly controversial. Several reports indicated osteogenic potential, whereas others showed inhibitory effects [ 82 , 83 , 84 ], clearly representing the context dependence of the CCN-induced biological outcomes. The osteogenic effects observed in certain studies might be caused via CCN2- or CCN3-specific molecular partners that were present in the microenvironment under the experimental conditions employed therein.…”