High expression of MAPK-14 promoting the death of chondrocytes is an important signal of osteoarthritis process

Exploration of the molecular mechanism of Wufu Yin in the treatment of knee osteoarthritis based on network pharmacology and experimental validation

Wufu Yin (WFY) exhibits significant clinical effectiveness in knee osteoarthritis (KOA) treatment, yet its therapeutic mechanisms are still unclear. This study aimed to explore the active ingredients and potential mechanism of WFY in the treatment of KOA. The network pharmacology-based approach was adopted to investigate the underlying mechanism of WFY in treating KOA. Molecular docking analysis was performed using Auto Vina software. An in vitro model of KOA inflammation was established by inducing chondrocyte cultures with interleukin-1 beta (IL-1β). Cell viability was quantified through the cell counting kit-8 assay, inflammatory cytokine levels were measured via ELISA, and protein expressions were assessed by Western blot analysis. A total of 225 active ingredients and 265 targets of WFY were identified, of which 88 were identified as potential targets against KOA. Enrichment analysis showed that these targets were associated with oxidative stress, cell proliferation and apoptosis, and inflammatory response, and were involved in the regulation of Th17 cell differentiation, IL-17 signaling pathway, tumor necrosis factor signaling pathway, and other signaling pathways. Topology analysis showed that PTGS2, NOS2, ESR11, PPARG, and MAPK14 had higher degree values and were key targets of WFY in the treatment of KOA. Molecular docking analysis showed that these key targets and active ingredients had low binding energies, indicating that they had potential binding activity. Furthermore, IL-1β-induced elevation of inflammatory cytokines, PTGS2 protein expression, and phosphorylated p38/p38 ratios in chondrocytes were significantly attenuated upon WFY intervention. Our study systematically elucidated the pharmacological basis and molecular mechanism underlying WFY's therapeutic effects in KOA, substantiating its ability to suppress inflammation and regulate PTGS2 expression and p38 phosphorylation.

Chelidonine reduces IL-1β-induced inflammation and matrix catabolism in chondrocytes and attenuates cartilage degeneration and synovial inflammation in rats

Chondrocyte inflammation and catabolism are two major features in the progression of osteoarthritis (OA). Chelidonine, a principal alkaloid extracted from Chelidonium majus, is suggested to show anti-inflammation, anti-apoptosis, and anti-oxidation activities in various diseases. However, its potential effects on OA cartilage degeneration remains unclear. To evaluate the effect of chelidonine on OA and its underlying mechanism, we incubated chondrocytes with interleukin (IL)-1β and chelidonine at varying concentrations. Then, we performed the CCK-8 assay, fluorescence immunostaining, reverse transcription PCR, ELISA, and western blotting to evaluate cell viability, catabolic/inflammatory factors, levels of extracellular matrix (ECM)-related proteins, and the involved pathways. H&E and Safranin-O staining and ELISA were performed to measure cartilage degradation and synovial inflammation. Chelidonine suppressed the IL-1β-mediated catabolism and inflammation of chondrocytes. Chelidonine suppressed the NF-κB pathway activation. Similarly, our in vivo experiment showed that chelidonine partially attenuated cartilage degradation while inhibiting synovial inflammation. Chelidonine inhibited inflammation and catabolism through modulation of NF-κB pathways in vitro, thereby avoiding rat cartilage degeneration and synovial inflammation within OA.

MiR-320a upregulation improves IL-1β-induced osteoarthritis via targeting the DAZAP1 and MAPK pathways

PURPOSE

Osteoarthritis (OA), a constant illness described by articular cartilage degeneration, usually manifested by joint pain and helpless development. Numerous literatures suggest that microRNAs play an important regulatory role in OA, yet the role of miR-320a in OA remains largely obscure.

MATERIALS AND METHODS

To evaluate the expression of miR-320a mRNA, quantitative real-time polymerase chain reaction was used. Cell counting kit-8 assay, Edu staining, Annexin V-FITC/PI apoptosis detection assay, Caspases 3 staining, and trypan staining were conducted to monitor cell proliferation and apoptosis. Western blot was applied to examine DAZAP1 and ERK/JNK/MAPK associated protein expression. Luciferase reporter gene experiments were performed to confirm the relationships between miR-320a and DAZAP1. ELISA assay was adopted to analyze the secretion of inflammation cytokines IL-6, IL-8, and TNF-α.

RESULTS

In an in vitro osteoarthritis model caused by IL-1β, miR-320a expression was markedly reduced. Overexpression of miR-320a restored IL-1β-inhibited chondrocyte proliferation, induced apoptosis and inflammatory response. Mechanistically, miR-320a affected HC-A cell proliferation, apoptosis and inflammatory response by regulating DAZAPI. Meanwhile, the ERK/JNK/MAPK pathway is also involved in the regulatory role of miR-320a on OA.

CONCLUSION

Our results show an important role for miR-320a and provide new therapeutic targets for avoiding and treating osteoarthritis.

Network Pharmacology and Molecular Docking to Elucidate the Potential Mechanism of Ligusticum Chuanxiong Against Osteoarthritis

Background: Osteoarthritis (OA) is a degenerative disease which serious affects patients. Ligusticum chuanxiong (CX) has been shown to have a certain curative effect on osteoarthritis in traditional Chinese medicine therapy. This study is based on network pharmacology and molecular docking technology to explore the potential mechanism of CX.

Methods: Components of CX to treat osteoarthritis were screened in the TCMSP database and targets were predicted by the PharmMapper database, the osteoarthritis targets were collected from the GeneCards database, and intersection genes were found to be the possible targets of CX anti-OA. The STRING database and Cytoscape software were utilized for protein-protein interaction analysis and further screening of core targets. The Metascape database was used for KEGG and GO enrichment analyses. Then, the top 10 pathways were selected to construct “drug-compound-target-pathway-disease” network analysis. Finally, molecular docking was used to analyze the binding affinity of seven compounds with core targets and TNF-α.

Results: Seven compounds with 253 non-repetitive targets of CX were screened from the TCMSP database and 60 potential intersection targets of CX anti-OA were found. PPI network analysis showed that the core targets were ALB, AKT1, IGF1, CASP3, MAPK1, ANXA5, and MAPK14, while GO and KEGG pathway enrichment analyses showed that the relevant biological processes involved in the treatment of osteoarthritis by CX might include the MAPK cascade and reactive oxygen species metabolic process. The KEGG pathway analysis result was mainly associated with the MAPK signaling pathway and PI3K-AKT signaling pathway. We further docked seven ingredients with MAPK1 and MAPK14 enriched in the MAPK pathway, and TNF-α as the typical inflammatory cytokine. The results also showed good binding affinity, especially FA, which may be the most important component of CX anti-OA.

Conclusion: Our research revealed the potential mechanism of CX in the treatment of OA, and our findings can also pave the way for subsequent basic experimental verification and a new research direction.

Superior stemness of a rapidly growing subgroup of isolated human auricular chondrocytes and the potential for use in cartilage regenerative therapy

Introduction

In cartilage regenerative medicine, transplanted chondrocytes contain a mixture of populations, that complicates the regeneration of uniform cartilage tissue. Our group previously reported that chondrocytes with higher chondrogenic ability could be enriched by selection of rapidly growing cells. In this study, the detailed properties of rapidly growing chondrocytes were examined and compared to slowly growing cells.

Methods

Human auricular chondrocytes were fluorescently labeled with carboxyfluorescein succinimidyl ester (CFSE) and analyzed using flow cytometry, focusing on division rates as indicated by fluorescence intensity and cell morphology according to the forward scatter and side scatter. Rapid and slow growing cell groups were harvested on days 2 and 4 after CFSE labeling, and their ability to produce cartilage matrix in vitro was examined. To compare the chondrogenic ability in vivo, the cells were seeded on poly-l-lactic acid scaffolds and transplanted into nude mice. Gene expression differences between the rapid and slow cell groups were investigated by microarray analysis.

Results

On day 2 after CFSE labeling, the rapidly growing cell group showed the highest proliferation rate. The results of pellet culture showed that the rapid cell group produced more glycosaminoglycans per cell than the slow cell group. The amount of glycosaminoglycan production was highest in the rapid cell group on day 2 after CFSE labeling, indicating high chondrogenic ability. Furthermore, microarray, gene ontology, and Kyoto Encyclopedia of Genes and Genomes pathway analyses showed upregulation of genes that promote cell division such as origin recognition complex subunit 1 and downregulation of genes that inhibit cell division such as cyclin dependent kinase inhibitor 1A. Besides cell cycle-related genes, chondrocyte-related genes such as serpin family B member 2, clusterin, bone morphogenetic protein 2, and matrix metalloproteinase 3 were downregulated, while fibroblast growth factor 5 which is involved in stem cell maintenance, and coiled-coil and C2 domain containing 2A, which is required for cilia formation, were upregulated.

Conclusion

The results showed that the rapid cell group proliferated well and had more undifferentiated properties, suggesting a higher stemness. The present findings provide a basis for the use of the rapid cell group in cartilage regeneration.

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Highly-chondrogenic chondrocytes can be enriched based on their high division rate.

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Rapidly dividing cells are smaller and have less granularity.

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Cell cycle-related genes are upregulated in rapidly dividing cells.

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Chondrocyte-related genes are downregulated in rapidly dividing cells.

The Homeostasis of Cartilage Matrix Remodeling and the Regulation of Volume-Sensitive Ion Channel

Degenerative joint diseases of the hips and knees are common and are accompanied by severe pain and movement disorders. At the microscopic level, the main characteristics of osteoarthritis are the continuous destruction and degeneration of cartilage, increased cartilage extracellular matrix catabolism, decreased anabolism, increased synovial fluid, and decreased osmotic pressure. Cell volume stability is mainly regulated by ion channels, many of which are expressed in chondrocytes. These ion channels are closely related to pain regulation, volume regulation, the inflammatory response, cell proliferation, apoptosis, and cell differentiation. In this review, we focus on the important role of volume control-related ion channels in cartilage matrix remodeling and summarize current views. In addition, the potential mechanism of the volume-sensitive anion channel LRRC8A in the early occurrence of osteoarthritis is discussed.

Physalin A Inhibits MAPK and NF-κB Signal Transduction Through Integrin αVβ3 and Exerts Chondroprotective Effect

Osteoarthritis (OA) is a common articular ailment presented with cartilage loss and destruction that is common observed in the elderly population. Physalin A (PA), a natural bioactive withanolide, exerts anti-inflammatory residences in more than a few diseases; however, little is known about its efficacy for OA treatment. Here, we explored the therapeutic effects and potential mechanism of PA in mouse OA. After the in vitro administration of PA, the expression of inflammation indicators including inducible nitric oxide synthase and cyclooxygenase-2 was low, indicating that PA could alleviate the IL-1β-induced chondrocyte inflammation response. Moreover, PA reduced IL-1β-induced destruction of the extracellular matrix by upregulating the gene expression of anabolism factors, including collagen II, aggrecan, and sry-box transcription factor 9, and downregulating the gene expression of catabolic factors, including thrombospondin motif 5 and matrix metalloproteinases. In addition, the chondroprotective effect of PA was credited to the inhibition of mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. Furthermore, in vivo experiments showed that intra-articular injection of PA could alleviate cartilage destruction in a mouse OA model. However, the anti-inflammatory, anabolism enhancing, catabolism inhibiting, and MAPK and NF-κB signaling pathway inhibiting properties of PA on IL-1β-induced chondrocytes could be reversed when integrin αVβ3 is knocked down by siRNA. In conclusion, our work demonstrates that PA exhibits a chondroprotective effect that may be mediated by integrin αVβ3. Thus, PA or integrin αVβ3 might be a promising agent or molecular target for the treatment of OA.

Sulfated modification enhances the immunomodulatory effect of Cyclocarya paliurus polysaccharide on cyclophosphamide-induced immunosuppressed mice through MyD88-dependent MAPK/NF-κB and PI3K-Akt signaling pathways

The present study investigated the effect of sulfation on the immunomodulatory effect of Cyclocarya paliurus polysaccharide (CP) through a Cyclophosphamide (CTX)-induced immunosuppression mice model. The results showed that sulfated Cyclocarya paliurus polysaccharide (SCP3) had stronger immunomodulatory ability than CP. Administration of SCP3 alleviated immune organ atrophy and restored hematopoiesis in immunosuppressed mice, enhanced splenocyte proliferation, and promoted cytokines and nitric oxide (NO) production in splenocyte supernatants, as well as the number of CD3+, CD4+ and CD8+ T lymphocytes. Meantime, SCP3 significantly improved oxidative stress via increasing the activities of antioxidant enzymes and decreasing the levels of malondialdehyde (MDA) in liver. In addition, SCP3 significantly upregulated the phosphorylation expression of JNK, Erk 1/2, p38 of MAPKs signaling pathway at a dose of 50 mg/kg and accordingly showed increased phosphorylation of Akt, NF-κB (p65), IκB-α, and promoted the degradation of IkB-α. Furthermore, SCP3 significantly increased the expression of the upstream signaling molecule MyD88. All results demonstrated that sulfation can be an effective way to enhance the immunomodulatory effect of polysaccharides. SCP3 has high potential to be a functional food supplement candidate for alleviating chemotherapy drug-induced immunosuppression.