3,3'-diindolylmethane inhibits LPS-induced human chondrocytes apoptosis and extracellular matrix degradation by activating PI3K-Akt-mTOR-mediated autophagy

3,3'-Diindolylmethane promotes bone formation - A assessment in MC3T3-E1 cells and zebrafish

Osteoporosis is a common degenerative bone disease in middle-aged and elderly people. The current drugs used to treat osteoporosis have many side effects and low patient compliance. Phytochemotherapy may be safer and more effective. 3,3'-diindolemethane (DIM) is the digestive product of indole-3-methanol in cruciferous vegetables in the stomach, which is a kind of anti-tumor and anti-oxidation phytochemical. However, the effects of DIM on osteoblasts and the mechanism by which DIM regulates bone formation are not fully understood. The aim of this study was to investigate the effects of DIM on the bone formation of mouse preosteoblasts MC3T3-E1 and zebrafish. DIM promotes proliferation and osteogenic differentiation of MC3T3-E1 cells in vitro, and also plays a bone promoting role by increasing the interaction between BRCA1-Associated Protein 1(BAP1) and Inositol 1,4,5-Trisphosphate Receptor(IP3R), up-regulating the expression of BAP1 and IP3R and downstream storage operation calcium entry (SOCE) related protein Recombinant Stromal Interaction Molecule 1(STIM1). The effect of DIM on osteoporosis was confirmed in zebrafish osteoporosis model, and its molecular mechanism may be related to BAP1/IP3R/SOCE signaling pathway. These findings highlight the potential therapeutic value of DIM in the prevention and treatment of osteoporosis.

Mechanism of Asperosaponin VI Related to EGFR/MMP9/AKT/PI3K Pathway in Treatment of Rheumtoid Arthritis

OBJECTIVE

To explore the mechanism of action of asperosaponin VI (AVI) in the treatment of rheumatoid arthritis (RA) and validate it in ex vivo experiments using network pharmacology and molecular docking methods.

METHODS

The predicted targets of AVI were obtained from PharmMaper, UniProt and SwissTarget Prediction platforms, the disease targets were collected from Online Mendelian Inheritance in Man, Therapeutic Target Database and GeneCards databases, the intersection targets of AVI and RA were obtained from Venny 2.1.0, and the protein-protein interaction (PPI) network was obtained from STRING database, which was analyzed by Cytoscape software and screened to obtain the core targets. Cytoscape software was used to analyze PPI network and screen the core targets. Based on the Database for Annotation, Visualization and Integrated Discovery database, Gene Ontology functional and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were performed, and Cytoscape software was used to construct the "Disease-Pathway-Target-Drug" network, which was finally verified by molecular docking and animal experiments.

RESULTS

Network pharmacological studies showed that AVI was able to modulate 289 targets, with 102 targets for the potential treatment of RA, with the core pathway being the AKT/PI3K signaling pathway, and the core targets being the epidermal growth factor receptor (EGFR) and matrix metalloproteinase 9 (MMP9). Molecular docking results showed that AVI could produce strong binding with both of the 2 core targets. In vitro cellular experiments showed that AVI reduced nitric oxide, prostaglandin E2, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and IL-1 β levels (P<0.05) and inhibited cyclooxygenase-2, nitric oxide synthase, EGFR, MMP9, phosphorylated phosphoinositide 3-kinase (p-PI3K), and phosphorylated serine-threonine kinase (p-AKT) proteins (P<0.05). The results of in vivo studies showed that AVI improved RA score and foot swelling thickness and decreased TNF-α, IL-6, p-PI3K and p-AKT levels in RA rats (P<0.05).

CONCLUSION

AVI exerts anti-inflammatory and anti-RA effects which might be related to the EGFR/MMP9/AKT/PI3K pathway.

Targeting PAR2-mediated inflammation in osteoarthritis: a comprehensive in vitro evaluation of oleocanthal's potential as a functional food intervention for chondrocyte protection and anti-inflammatory effects

BACKGROUND

Osteoarthritis (OA) is a prevalent degenerative joint disease characterized by chronic inflammation and progressive cartilage degradation, ultimately leading to joint dysfunction and disability. Oleocanthal (OC), a bioactive phenolic compound derived from extra virgin olive oil, has garnered significant attention due to its potent anti-inflammatory properties, which are comparable to those of non-steroidal anti-inflammatory drugs (NSAIDs). This study pioneers the investigation into the effects of OC on the Protease-Activated Receptor-2 (PAR-2) mediated inflammatory pathway in OA, aiming to validate its efficacy as a functional food-based therapeutic intervention.

METHODS

To simulate cartilage tissue in vitro, human bone marrow-derived mesenchymal stem cells (BMSCs) were differentiated into chondrocytes. An inflammatory OA-like environment was induced in these chondrocytes using lipopolysaccharide (LPS) to mimic the pathological conditions of OA. The therapeutic effects of OC were evaluated by treating these inflamed chondrocytes with various concentrations of OC. The study focused on assessing key inflammatory markers, catabolic enzymes, and mitochondrial function to elucidate the protective mechanisms of OC. Mitochondrial function, specifically mitochondrial membrane potential (ΔΨm), was assessed using Rhodamine 123 staining, a fluorescent dye that selectively accumulates in active mitochondria. The integrity of ΔΨm serves as an indicator of mitochondrial and bioenergetic function. Additionally, Western blotting was employed to analyze protein expression levels, while real-time polymerase chain reaction (RT-PCR) was used to quantify gene expression of inflammatory cytokines and catabolic enzymes. Flow cytometry was utilized to measure cell viability and apoptosis, providing a comprehensive evaluation of OC's therapeutic effects on chondrocytes.

RESULTS

The results demonstrated that OC significantly downregulated PAR-2 expression in a dose-dependent manner, leading to a substantial reduction in pro-inflammatory cytokines, including TNF-α, IL-1β, and MCP-1. Furthermore, OC attenuated the expression of catabolic markers such as SOX4 and ADAMTS5, which are critically involved in cartilage matrix degradation. Importantly, OC was found to preserve mitochondrial membrane potential (ΔΨm) in chondrocytes subjected to inflammatory stress, as evidenced by Rhodamine 123 staining, indicating a protective effect on cellular bioenergetics. Additionally, OC modulated the Receptor Activator of Nuclear Factor Kappa-Β Ligand (RANKL)/Receptor Activator of Nuclear Factor Kappa-Β (RANK) pathway, suggesting a broader therapeutic action against the multifactorial pathogenesis of OA.

CONCLUSIONS

This study is the first to elucidate the modulatory effects of OC on the PAR-2 mediated inflammatory pathway in OA, revealing its potential as a multifaceted therapeutic agent that not only mitigates inflammation but also protects cartilage integrity. The preservation of mitochondrial function and modulation of the RANKL/RANK pathway further underscores OC's comprehensive therapeutic potential in counteracting the complex pathogenesis of OA. These findings position OC as a promising candidate for integration into nutritional interventions aimed at managing OA. However, further research is warranted to fully explore OC's therapeutic potential across different stages of OA and its long-term effects in musculoskeletal disorders.

Epigallocatechin gallate protects MC3T3-E1 cells from cadmium-induced apoptosis and dysfunction via modulating PI3K/AKT/mTOR and Nrf2/HO-1 pathways

Epigallocatechin gallate (EGCG), an active constituent of tea, is recognized for its anticancer and anti-inflammatory properties. However, the specific mechanism by which EGCG protects osteoblasts from cadmium-induced damage remains incompletely understood. Here, the action of EGCG was investigated by exposing MC3T3-E1 osteoblasts to EGCG and CdCl2 and examining their growth, apoptosis, and differentiation. It was found that EGCG promoted the viability of cadmium-exposed MC3T3-E1 cells, mitigated apoptosis, and promoted both maturation and mineralization. Additionally, CdCl2 has been reported to inhibit both the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) and nuclear factor erythroid 2-related factor 2/heme oxygenase-1(Nrf2/HO-1) signaling pathways. EGCG treatment attenuated cadmium-induced apoptosis in osteoblasts and restored their function by upregulating both signaling pathways. The findings provide compelling evidence for EGCG's role in attenuating cadmium-induced osteoblast apoptosis and dysfunction through activating the PI3K/AKT/mTOR and Nrf2/HO-1 pathways. This suggests the potential of using EGCG for treating cadmium-induced osteoblast dysfunction.

The dysregulated autophagy in osteoarthritis: Revisiting molecular profile

The risk factors of osteoarthritis (OA) are different and obesity, lifestyle, inflammation, cell death mechanisms and diabetes mellitus are among them. The changes in the biological mechanisms are considered as main regulators of OA pathogenesis. The dysregulation of autophagy is observed in different human diseases. During the pathogenesis of OA, the autophagy levels (induction or inhibition) change. The supportive and pro-survival function of autophagy can retard the progression of OA. The protective autophagy prevents the cartilage degeneration. Moreover, autophagy demonstrates interactions with cell death mechanisms and through inhibition of apoptosis and necroptosis, it improves OA. The non-coding RNA molecules can regulate autophagy and through direct and indirect control of autophagy, they dually delay/increase OA pathogenesis. The mitochondrial integrity can be regulated by autophagy to alleviate OA. Furthermore, therapeutic compounds, especially phytochemicals, stimulate protective autophagy in chondrocytes to prevent cell death. The protective autophagy has ability of reducing inflammation and oxidative damage, as two key players in the pathogenesis of OA.