Osteoporosis is widely recognized as a major health problem caused by an inappropriate rate of bone resorption compared to bone formation. Previously we showed that d-pinitol inhibits osteoclastogenesis but has no effect on osteoblastogenesis. However, the effect on osteoblast differentiation of its isomer, l-quebrachitol, has not yet been reported. The purpose of this study was, therefore, to investigate whether l-quebrachitol promotes the osteoblastogenesis of pre-osteoblastic MC3T3-E1 cells. Moreover, the molecular mechanism of action of l-quebrachitol was further explored. Here, it is shown for the first time that l-quebrachitol significantly promotes proliferation and cell DNA synthesis. It also enhances mineralization accompanied by increases in mRNA expression of bone matrix proteins including alkaline phosphatase (ALP), collagen type I (ColI), osteocalcin (OCN), and osteopontin (OPN). In addition, l-quebrachitol upregulates the mRNA and protein expression of bone morphogenetic protein-2 (BMP-2) and runt-related transcription factor-2 (Runx2), while down-regulating the receptor activator of the nuclear factor-κB ligand (RANKL) mRNA level. Moreover, the expression of regulatory genes associated with the mitogen-activated protein kinase (MAPK) and wingless-type MMTV integration site (Wnt)/β-catenin signaling pathways are also upregulated. These findings indicate that l-quebrachitol may promote osteoblastogenesis by triggering the BMP-2-response as well as the Runx2, MAPK, and Wnt/β-catenin signaling pathway.

Osteoporosis is a leading world health problem that results from an imbalance between bone formation and bone resorption. β-glucans has been extensively reported to exhibit a wide range of biological activities, including antiosteoporosis both in vitro and in vivo. However, the molecular mechanisms responsible for β-glucan-mediated bone formation in osteoblasts have not yet been investigated. The oyster mushroom Pleurotus sajor-caju produces abundant amounts of an insoluble β-glucan, which is rendered soluble by enzymatic degradation using Hevea glucanase to generate low-molecular-weight glucanoligosaccharide (Ps-GOS). This study aimed to investigate the osteogenic enhancing activity and underlining molecular mechanism of Ps-GOS on osteoblastogenesis of pre-osteoblastic MC3T3-E1 cells. In this study, it was demonstrated for the first time that low concentrations of Ps-GOS could promote cell proliferation and division after 48 h of treatment. In addition, Ps-GOS upregulated the mRNA and protein expression level of bone morphogenetic protein-2 (BMP-2) and runt-related transcription factor-2 (Runx2), which are both involved in BMP signaling pathway, accompanied by increased alkaline phosphatase (ALP) activity and mineralization. Ps-GOS also upregulated the expression of osteogenesis related genes including ALP, collagen type 1 (COL1), and osteocalcin (OCN). Moreover, our novel findings suggest that Ps-GOS may exert its effects through the mitogen-activated protein kinase (MAPK) and wingless-type MMTV integration site (Wnt)/β-catenin signaling pathways.

This study aimed to determine the most suitable recombinant fortilin and evaluate the biological activities of glass ionomer cement (GIC) incorporated with fortilin on human dental pulp stem cells (hDPSCs). Full-length and three fragments of Penaeus merguiensis fortilin were cloned and examined for their proliferative and cytoprotective effects on hDPSCs by MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay. Human DPSCs were cultured with GIC supplemented with fortilin, tricalcium phosphate, or a combination of tricalcium phosphate and fortilin, designated as GIC + FL, GIC + TCP, and GIC + TCP + FL, respectively (n = 4 for each group). At given time points, hDPSCs were harvested and analyzed by MTT, quantitative reverse transcription polymerase chain reaction, alkaline phosphatase activity, and Alizarin Red assays. The full-length fortilin promoted cell proliferation and significantly increased cell survival. This protein was subsequently added into the GIC along with tricalcium phosphate to investigate the biological activities. All experimental groups showed reduced cell viability after treatment with modified GICs on days 1 and 3. The GIC + TCP + FL group significantly promoted odontoblastic differentiation at particular time points. In addition, alkaline phosphatase activity and calcium phosphate deposit were markedly increased in the GIC + TCP + FL group. Among all experimental groups, the GIC incorporated with fortilin and tricalcium phosphate demonstrated the best results on odontogenic differentiation and mineral deposition in hDPSCs.

The development of biomaterials that are able to control the release of bioactive molecules is a challenging task for regenerative dentistry. This study aimed to enhance resin-modified glass ionomer cement (RMGIC) for the release of epidermal growth factor (EGF). This RMGIC was formulated from RMGIC powder supplemented with 15% (w/w) chitosan at a molecular weight of either 62 or 545 kDa with 5% bovine serum albumin mixed with the same liquid component as the Vitrebond. EGF was added while mixing. ELISA was used to determine EGF release from the specimen immersed in phosphate-buffered saline at 1 h, 3 h, 24 h, 3 d, 1 wk, 2 wks, and 3 wks. Fluoride and aluminum release at 1, 3, 5, and 7 d was measured by electrode and inductively coupled plasma optical emission spectrometry. Pulp cell viability was examined through MTT assays and the counting of cell numbers using a Coulter counter. The RMGIC with 65 kDa chitosan is able to prolong the release of EGF for significantly longer than RMGIC for at least 3 wks due to its retained bioactivity in promoting pulp cell proliferation. This modified RMGIC can prolong the release of fluoride, with a small amount of aluminum also released for a limited time. This biomaterial could be useful in regenerating pulp–dentin complexes.