Limonoid Triterpene, Obacunone Increases Runt-Related Transcription Factor 2 to Promote Osteoblast Differentiation and Function

Abstract

Root bark of Dictamnus dasycarpus Turcz. has been widely used as a traditional medicine and is a well-known anti-inflammatory agent. We isolated limonoid triterpene, obacunone (Obac) from the dried root bark of D. dasycarpus. Obac has been reported to exhibit varieties of biological activities including anti-inflammatory, anti-cancer, and anti-oxidant effects. This study aimed to investigate the beneficial effects and biological mechanisms of Obac in osteoblast differentiation and bone matrix mineralization. In the present study, Obac at concentrations ranging from 1 to 100 μM showed no proliferation effects in MC3T3-E1. The treatment of Obac (1 and 10 μM) increased wound healing and migration rates in a dose-dependent manner. Alkaline phosphatase (ALP) staining and activity showed that Obac (1 and 10 μM) enhanced early osteoblast differentiation in a dose-dependent manner. Obac also increased late osteoblast differentiation in a dose-dependent manner, as indicated by the mineralized nodule formation of ARS staining. The effects of Obac on osteoblast differentiation was validated by the levels of mRNAs encoding the bone differentiation markers, including Alp, bone sialoprotein (Bsp), osteopontin (Opn), and osteocalcin (Ocn). Obac increased the expression of bone morphogenetic protein (BMP), and the phosphorylation of smad1/5/8, and the expression of runt-related transcription factor 2 (RUNX2); Obac also inhibited GSK3β and upregulated the protein level of β-catenin in a dose-dependent manner during osteoblast differentiation. Obac-mediated osteoblast differentiation was attenuated by a BMP2 inhibitor, Noggin and a Wnt/β-catenin inhibitor, Dickkopf-1 (Dkk1) with the abolishment of RUNX2 expression and nuclear accumulation by Obac. Taken together, the findings of this study demonstrate that Obac has pharmacological and biological activates to promote osteoblast differentiation and bone mineralization through BMP2, β-catenin, and RUNX2 pathways, and suggest that Obac might be a therapeutic effect for the treatment and prevention of bone diseases such as osteoporosis and periodontitis.

Breast Cancer with Bone Metastasis: Molecular Insights and Clinical Management

“…Among these, IGF1 activates phosphoinositide 3-kinase (PI3K)/Akt mammalian target of rapamycin (mTOR) pathway, with subsequent breast cancer cell growth, proliferation, and migration into the bone [17,61,62]. Osteoblasts can also be regulated by metastatic tumor cell-derived factors including endothelin 1 (ET1), dickkopf 1 (DKK1), and the Wnt signaling cascade [36,[63][64][65][66]. While Wnt promotes osteoblast differentiation, its activity can be inhibited by DKK1, which is an antagonist in this cascade.…”

Hsa_circ_0001485 promoted osteogenic differentiation by targeting BMPR2 to activate the TGFβ-BMP pathway

“…Increased ALP activity enhances bone formation and promotes the formation of bone matrix mineralization [ 47 ]. As an essential transcription factor for osteoblast differentiation, RUNX2 encourages the expression of osteoblast secretion proteins, OCN and OPN [ 48 ]. After inhibiting hsa_circ_0001485 with small interfering RNA, we found that the ALP enzyme activity in human osteoblast hFOB 1.19 cells was significantly reduced, and the number of calcified nodules was also reduced.…”

Trifloroside Induces Bioactive Effects on Differentiation, Adhesion, Migration, and Mineralization in Pre-Osteoblast MC3T3E-1 Cells

“…Various plant-derived compounds have been reported to promote osteogenesis, osteoid formation, hydroxyapatite synthesis, and mineral apposition via multiple signaling pathways and transcription factors [ 5 , 6 , 15 , 16 ]. All of these studies provided novel drug research, development, and clinical applications for treating bone diseases [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”

“…Osteoblast differentiation is induced and controlled through complex signaling pathways, primarily Wnt3a- and bone morphogenetic protein 2 (BMP2)-mediated signaling molecules, as well as mitogen-activated protein kinases (MAPKs) and AKT, which induce the expression of Runt-related transcription factor 2 (RUNX2) and regulate the transcriptional activity in osteoblast differentiation [ 2 , 3 , 4 ]. Consequently, osteoblast differentiation and maturation produce osteoids through synthesis and secretion to construct the bone matrix, which then leads to mineralization of the bone matrix filled around collagen rope containing dense and irregular crystals of hydroxyapatite that bestow rigidity to the bone [ 5 , 6 ]. In contrast, the dysregulation and impairment of osteoblast differentiation and maturation are mainly responsible for the pathogenesis of diseases including osteoporosis-induced bone fractures and periodontitis-induced alveolar bone loss [ 7 , 8 ].…”