Eurycomanone stimulates bone mineralization in zebrafish larvae and promotes osteogenic differentiation of mesenchymal stem cells by upregulating AKT/GSK-3β/β-catenin signaling

Eurycomanone inhibits osteosarcoma growth and metastasis by suppressing GRP78 expression

ETHNOPHARMACOLOGICAL RELEVANCE

Osteosarcoma (OS) is characterized by rapid growth and frequent pulmonary metastasis. Eurycoma longifolia Jack, a flowering plant primarily found in Southeast Asian countries, is commonly used in traditional herbal medicine. Its root extract is mainly used for against cancer, malaria, parasites and other conditions. The active compound in its root extract, eurycomanone (EUR), has been proven to inhibit lung and liver cancer proliferation.

AIM OF THE STUDY

Our research aimed to investigate the inhibitory effect and underlying molecular mechanism of EUR on OS growth and metastasis.

MATERIALS AND METHODS

In vitro experiments: western blotting (WB) screened 41 compounds that inhibited GRP78 expression and evaluated the protein levels of GRP78, PARP, cleaved-PARP, MMP2, and MMP9. Cell proliferation was evaluated using CCK-8, EdU, colony formation assay, and cell apoptosis was assessed by flow cytometry. Transwell, wound healing, and tube formation assays were performed to determine the effect of EUR on tumor invasion, migration, and angiogenesis, respectively. Quantitative real-time polymerase chain (qRT-PCR) and dual-luciferase activity assays detected GRP78 mRNA stability and transcription levels post-EUR and thapsigargin treatment. RNA-Seq identified signaling pathways inhibited by EUR. In vivo experiments: effects of EUR in mice were evaluated by H&E staining to detect lung metastasis and potential toxic effects in tissues. Immunohistochemical (IHC) staining detected the expression of Ki-67, CD31, and cleaved caspase-3 in tumors.

RESULTS

GRP78 is highly expressed in OS and correlated with poor prognosis. In vitro, eurycomanone (EUR) significantly downregulated GRP78 expression, inhibited cell proliferation, migration, invasion, tube formation, and induced apoptosis. Moreover, it enhanced trichostatin A (TSA) sensitivity and exhibited inhibitory effects on other cancer types. Mechanistically, EUR decreased GRP78 mRNA stability and transcription. In vivo, EUR inhibited proliferation and invasion in tibial and PDX models.

CONCLUSIONS

Our study demonstrated that EUR inhibits the growth and metastasis of OS by reducing GRP78 mRNA stability and inhibiting its transcription, which offers a novel approach for clinical treatment of OS.

7,8-DHF inhibits BMSC oxidative stress via the TRKB/PI3K/AKT/NRF2 pathway to improve symptoms of postmenopausal osteoporosis

Postmenopausal osteoporosis (PMO) is characterized by bone loss and microstructural damage, and it is most common in older adult women. Currently, there is no cure for PMO. The flavonoid chemical 7,8-dihydroxyflavone (7,8-DHF) specifically activates tropomyosin receptor kinase B (TRKB). Furthermore, 7,8-DHF has various biological characteristics, including anti-inflammatory and antioxidant effects. However, the specific implications and fundamental mechanisms of 7,8-DHF in PMO remain unclear. We used protein imprinting, flow cytometry, tissue staining, and other methods to estimate the preventive mechanisms of 7,8-DHF against hydrogen peroxide (H2O2)-induced apoptosis in primary mouse bone marrow mesenchymal stem cells (BMSCs), osteogenic differentiation ability, and bone mass in ovariectomized (OVX) mice. We found that 7,8-DHF effectively prevented H2O2-induced reductions in the viability and osteogenic differentiation capacity of primary BMSCs. Mechanistically, 7,8-DHF induced the TRKB to activate the PI3K/AKT/NRF2 pathway. In vivo experiments with the OVX mouse model confirmed that 7,8-DHF can inhibit oxidative stress and promote bone formation, indicating that 7,8-DHF improves the viability and osteogenic differentiation ability of BMSCs stimulated via H2O2 by activating the TRKB/PI3K/AKT and NRF2 pathways, thereby improving PMO.

Ultrasound-triggered piezoelectric polyetheretherketone with boosted osteogenesis via regulating Akt/GSK3β/β-catenin pathway

Maxillofacial bone defects can severely impact quality of life by impairing physiological functions such as chewing, breathing, swallowing, and pronunciation. Polyether ether ketone (PEEK) is commonly used for the repair of maxillofacial defects due to its mechanical adaptability, while its osteogenic properties still need refinement. Herein, we have utilized the piezoelectric effect exhibited by barium titanate (BTO) under low-intensity pulsed ultrasound (LIPUS) to develop an ultrasound responsive PEEK (PDA@BTO-SPEEK, PBSP) through the mediating effect of polydopamine (PDA), for repairing maxillofacial bone defects. After modification by PDA@BTO, PBSP possesses better hydrophilicity, which is conducive to cell growth and adhesion. Simultaneously, by virtue of the piezoelectric characteristics of BTO, PBSP obtains a piezoelectric coefficient that matches the bone cortex. Notably, when PBSP is stimulated by LIPUS, it can generate stable electricity and effectively accelerate the osteogenic differentiation of osteoblasts through the regulation of the Piezo1-induced calcium (Ca2+) influx and Akt/GSK3β/β-catenin pathway. In addition, PBSP presents satisfactory therapeutic effects in rat skull defect models, and its osteogenic efficiency can be further improved under LIPUS stimulation with high tissue penetration. Collectively, PBSP + LIPUS exhibits great potential as a promising alternative strategy for the repair of maxillofacial bone defects.

Potential therapeutic role of spermine via Rac1 in osteoporosis: Insights from zebrafish and mice

Osteoporosis is a prevalent metabolic bone disease. While drug therapy is essential to prevent bone loss in osteoporotic patients, current treatments are limited by side effects and high costs, necessitating the development of more effective and safer targeted therapies. Utilizing a zebrafish ( Danio rerio) larval model of osteoporosis, we explored the influence of the metabolite spermine on bone homeostasis. Results showed that spermine exhibited dual activity in osteoporotic zebrafish larvae by increasing bone formation and decreasing bone resorption. Spermine not only demonstrated excellent biosafety but also mitigated prednisolone-induced embryonic neurotoxicity and cardiotoxicity. Notably, spermine showcased protective attributes in the nervous systems of both zebrafish embryos and larvae. At the molecular level, Rac1 was identified as playing a pivotal role in mediating the anti-osteoporotic effects of spermine, with P53 potentially acting downstream of Rac1. These findings were confirmed using mouse ( Mus musculus) models, in which spermine not only ameliorated osteoporosis but also promoted bone formation and mineralization under healthy conditions, suggesting strong potential as a bone-strengthening agent. This study underscores the beneficial role of spermine in osteoporotic bone homeostasis and skeletal system development, highlighting pivotal molecular mediators. Given their efficacy and safety, human endogenous metabolites like spermine are promising candidates for new anti-osteoporotic drug development and daily bone-fortifying agents.

Combined toxicity of trifloxystrobin and fluopyram to zebrafish embryos and the effect on bone development

Trifloxystrobin (TRI) is a methacrylate fungicide, and fluopyram (FLU) is a new pyridylethylbenzamide fungicide and nematicide. Both are often detected in water bodies and may be highly toxic to many aquatic organisms. Unfortunately, the aquatic biological risks of single FLU or a mixture of trifloxystrobin and fluopyram have not been reported. In this study, zebrafish was selected as the test organism to investigate the combined toxicity of trifloxystrobin and fluopyram to zebrafish. After zebrafish embryos exposed to three pesticide solutions, Alcian-blue staining, Alizarin-red staining and quantitative PCR (qPCR) were performed. The results indicated that 96h-LC50 of TRI was 0.159 mg·L-1 to zebrafish embryo, which was highly toxic. The 96h-LC50 of FLU to zebrafish embryos was 4.375 mg·L-1, being moderately toxic. The joint toxicity to zebrafish embryos(FLU at 96h-LC50 and TRI at 96h-LC50 in a 1:1 weight ratio to form a series of concentration treatment groups) was antagonistic. Both trifloxystrobin and fluopyram also inhibited the skeletal development of zebrafish and showed to be antagonistic. The results of qPCR indicated upregulations of different genes upon three different treatments. TRI mainly induced Smads up-expression, which may affect the BMP-smads pathway. FLU mainly induced an up-expression of extracellular BMP ligands and type I receptor (Bmpr-1a), which may affect the BMP ligand receptor pathway. The 1:1 mixture (weight ratio) of trifloxystrobin and fluopyram induced a reduction of the genes of extracellular BMP ligand (Smads) and type I receptor (Bmpr1ba), which may down-regulate BMP signaling and thus attenuating cartilage hyperproliferation, hypertrophy and mineralization. The results warren an interest in further studying the effect of the two fungicides in a mixture on zebrafish.