Network Pharmacology-Based Analysis on the Action Mechanism of Oleanolic Acid to Alleviate Osteoporosis.

Oleanolic acid (OA) is a triterpenoid commonly found in plants and has shown extensive pharmaceutical activities. This study aimed to investigate the underlying mechanism of antiosteoporosis (OP) action of OA by utilizing the network pharmacology approach and molecular docking methods. First, the targets of OA were identified using the GeneCards, Stitch, and Swisstarget databases, and the targets related to OP were mined using the NCBI, Genecards, and DisGeNet databases. The overlapped targets of OA and OP were regarded as candidate targets, and the String database was used to obtain the protein-protein interactions among the targets. Then, Gene Ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway enrichment pathways of the candidate targets were performed using the DAVID database. In addition, the top 16 targets in the protein interaction network were used for molecular docking. Finally, an animal model constructed using d-galactose-induced oxidative stress and a low-calcium diet with accelerated bone loss was used to verify the in vivo effects of OA on osteoporotic mice. A total of 42 candidate targets for OA to treat OP were obtained. According to the protein-protein interaction network, MAPK1 showed the highest connectivity with other proteins. Additionally, GO analysis identified the top 20 biological processes, 9 cellular components, and top 20 molecular functions. Moreover, the candidate targets were mainly involved in 13 signaling pathways such as TNF signaling pathway, insulin resistance, MAPK signaling pathway, apoptosis, and PI3K-Akt signaling pathways. Furthermore, molecular docking revealed that OA has a high degree of connections with 16 key proteins. In addition, the anti-OP effects of OA are further validated through the in vivo model. Altogether, our study elucidated the candidate targets for OA to alleviate OP, explored the protein-protein interactions and related signaling pathways of the targets, and validated the anti-OP effects of OA. It could provide a better understanding of the action mechanism in OA to treat OP.

Tetrahydroxystilbene Glucoside Regulates Proliferation, Differentiation, and OPG/RANKL/M-CSF Expression in MC3T3-E1 Cells via the PI3K/Akt Pathway.

Tetrahydroxystilbene glucoside (TSG) is a unique component of the bone-reinforcing herb Radix Polygoni Multiflori Preparata (RPMP). It has the ability to promote bone formation and protect osteoblasts. However, the underlying mechanism remains unclear. To better understand its biological function, we determined TSG's effect on murine pre-osteoblastic MC3T3-E1 cells by the MTT assay, flow cytometry, FQ-PCR, Western blot, and ELISA. The results showed that TSG caused an elevation of the MC3T3-E1 cell number, the number of cells in the S phase, and the mRNA levels of the runt-related transcription factor-2 (Runx2), osterix (Osx), and collagen type I α1 (Col1a1). In addition, the osteoprotegerin (OPG) mRNA level was up-regulated, while the nuclear factor-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF) mRNA levels were down-regulated by TSG. Furthermore, TSG activated the phosphoinosmde-3-kinase/protein kinase B (also known as PI3K/Akt) pathway, and blocking this pathway by the inhibitor LY-294002 could impair TSG's functions in relation to the MC3T3-E1 cells. In conclusion, TSG could activate the PI3K/Akt pathway and thus promote MC3T3-E1 cell proliferation and differentiation, and influence OPG/RANKL/M-CSF expression. TSG merits further investigation as a potential therapeutic agent for osteoporosis treatment.

Effect of Fructus Ligustri Lucidi on osteoblastic like cell-line MC3T3-E1.

UNLABELLED: Fructus Ligustri Lucidi, fruits of Ligustrum lucidum Ait. (Oleaceae), has the effects of tonifying the liver and the kidney and strengthening the bones and muscles. In ancient times, Fructus Ligustri Lucidi can be prepared in ethanol or in water. Some active compounds have been found in Fructus Ligustri Lucidi, like Oleanolic acid and Ursolic acid, and Ursolic acid were proved to have osteogenic effects. METHODS AND RESULTS: To prove that Fructus Ligustri Lucidi water extract have osteogenic effects on MC3T3-E1 cells and how these effects work, we used CCK-8 (cell counting kit-8), ELISA (enzyme-linked immunosorbent assay), FQ-PCR (realtime fluorescence quantitative PCR) and western blot assays. After treatment with Fructus Ligustri Lucidi for 48h, 72h, 96h, the cell viability was marked increased, on concentration-dependently and time-dependently pattern. High and low concentrations of Fructus Ligustri Lucidi promoted differentiation of cells. Fructus Ligustri Lucidi could up-regulate OPG and RANKL protein in supernatant at 48h and 72h except for highest concentration (10(-1)mg/ml). Fructus Ligustri Lucidi promote OPG and RANKL mRNA expression at 48h and 72h, while the level of promoting at 72 was higher than 48h. 10(-5)mg/ml of Fructus Ligustri Lucidi up-regulates OPG protein expression and down-regulates RANKL protein expression. After treatment with Fructus Ligustri Lucidi water extract, inhibitors, Fructus Ligustri Lucidi water extract with inhibitors for 72h, inhibitors PD 98059, SB 203580, SP600125 and LY 294002 showed Fructus Ligustri Lucidi-induced cell proliferation and the leakage of OPG proteins effects. Fructus Ligustri Lucidi promoted the protein levels of ERK, p-ERK, p-JNK, p38, pp38, AKT and p-AKT, and inhibited the protein levels of JNK. CONCLUSIONS: Fructus Ligustri Lucidi water extract promoted cell proliferation and differentiation, mRNA and protein expression of OPG and RANKL on MC3T3-E1 cells. The effects of cell proliferation and leakage of OPG related to MAPK and AKT signaling pathways in different ways.