Injury-related cell death and proteoglycan loss in articular cartilage: Numerical model combining necrosis, reactive oxygen species, and inflammatory cytokines

Deferoxamine alleviates chondrocyte senescence and osteoarthritis progression by maintaining iron homeostasis

BACKGROUND

Osteoarthritis (OA) is a prevalent age-related disease characterized by the gradual deterioration of cartilage. The involvement of chondrocyte senescence is crucial in the pathogenesis of OA. Desferoxamine (DFO) is an iron chelator with therapeutic potential in various diseases. However, the relationship of chondrocyte senescence and iron homeostasis is largely unknown.

METHODS

Chondrocyte senescence was induced using tert-butyl hydroperoxide (TBHP), and the impact of DFO on chondrocyte senescence and iron metabolism was assessed through techniques such as western blotting, qRT-PCR, and β-Galactosidase staining. To assess the impact of DFO on chondrocyte senescence and the progression of osteoarthritis (OA), the surgical destabilization of the medial meniscus model was established.

RESULTS

In chondrocytes, TBHP administration resulted in elevated expression of P16, P21, and P53, as well as alterations in SA-β-gal staining. Nevertheless, DFO effectively mitigated chondrocyte senescence induced by TBHP, and reversed the decrease in collagen II expression and increase in MMP13 expression caused by TBHP. Mechanismly, TBHP induced NCOA4 expression and iron release in chondrocytes. Excessive iron could induce chondrocyte senescence, whereas, DFO could inhibit NCOA4 expression and restore ferritin level, and chelate excessive iron. Importantly, intra-articular injection of DFO enhanced collagen II expression and reduced expression of P16, P21, and MMP13 of cartilage in OA mice, and delayed cartilage degeneration.

CONCLUSIONS

Overall, this study provides evidence that DFO has the potential to alleviate chondrocyte senescence induced by TBHP and slow down the progression of osteoarthritis (OA) by effectively chelating excessive iron. These findings suggest that iron chelation could be a promising therapeutic strategy for treating OA.

COL3A1 is a potential diagnostic biomarker for synovial chondromatosis and affects the cell cycle and migration of chondrocytes

BACKGROUND

Synovial chondromatosis (SC) primarily affects the major joints and is characterized by the formation of benign cartilaginous nodules. In the present study, we evaluated the differences in the histology and gene expression of SC and normal cartilages and further elucidated the function of hub genes in SC.

METHODS

Histological staining and biochemical analysis were performed to measure collagen and glycosaminoglycan (GAG) contents in SC and normal cartilage samples. Then, microarray analysis was performed using knee joint samples (three normal and three SC samples) to identify the differentially expressed genes (DEGs). Subsequently, bioinformatics analysis was performed to identify the hub genes and explore the mechanisms underlying SC. The intersection of the top 10 upregulated DEGs, top 10 downregulated DEGs, and hub genes was validated in SC tissues. Lastly, in vitro experiments and our clinical cohort were used to determine the potential biological functions and diagnostic value, respectively, of the most significant gene.

RESULTS

The GAG and collagen contents were comparable to or higher in SC tissues than in normal tissues. Microarray analysis revealed 143 upregulated and 107 downregulated DEGs in SC. Furthermore, functional enrichment analysis revealed an association between immunity and metabolism-related pathways and SC development. Among 20 hub genes, two intersection genes, namely, collagen type III alpha 1 chain (COL3A1) and HSPA8, were notably expressed in SC tissues, with COL3A1 exhibiting a more significant difference in mRNA expression. Furthermore, COL3A1 can promote chondrocyte migration and cell cycle progression. Additionally, clinical data revealed COL3A1 can be a diagnostic marker for primary SC (AUC = 0.82) and be a positive correlation with neutrophil-to-lymphocyte ratio.

CONCLUSIONS

These results suggest that SC tissues contained the abundant GAG and collagen. COL3A1 can affect the function of chondrocytes and be a diagnostic marker of primary SC patients. These findings provide a novel approach and a fundamental contribution for diagnosis and treatment in SC.

Molecular Foundations of Inflammatory Diseases: Insights into Inflammation and Inflammasomes

Inflammatory diseases are a global health problem affecting millions of people with a wide range of conditions. These diseases, including inflammatory bowel disease (IBD), rheumatoid arthritis (RA), osteoarthritis (OA), gout, and diabetes, impose a significant burden on patients and healthcare systems. A complicated interaction between genetic variables, environmental stimuli, and dysregulated immune responses shows the complex biological foundation of various diseases. This review focuses on the molecular mechanisms underlying inflammatory diseases, including the function of inflammasomes and inflammation. We investigate the impact of environmental and genetic factors on the progression of inflammatory diseases, explore the connection between inflammation and inflammasome activation, and examine the incidence of various inflammatory diseases in relation to inflammasomes.

Targeting the Inflammatory Hallmarks of Obesity-Associated Osteoarthritis: Towards Nutraceutical-Oriented Preventive and Complementary Therapeutic Strategies Based on n-3 Polyunsaturated Fatty Acids

Obesity (Ob), which has dramatically increased in the last decade, is one of the main risk factors that contribute to the incidence and progression of osteoarthritis (OA). Targeting the characteristics of obesity-associated osteoarthritis (ObOA) may offer new chances for precision medicine strategies in this patient cohort. First, this review outlines how the medical perspective of ObOA has shifted from a focus on biomechanics to the significant contribution of inflammation, mainly mediated by changes in the adipose tissue metabolism through the release of adipokines and the modification of fatty acid (FA) compositions in joint tissues. Preclinical and clinical studies on n-3 polyunsaturated FAs (PUFAs) are critically reviewed to outline the strengths and weaknesses of n-3 PUFAs' role in alleviating inflammatory, catabolic and painful processes. Emphasis is placed on potential preventive and therapeutic nutritional strategies based on n-3 PUFAs, with a focus on ObOA patients who could specifically benefit from reformulating the dietary composition of FAs towards a protective phenotype. Finally, tissue engineering approaches that involve the delivery of n-3 PUFAs directly into the joint are explored to address the perspectives and current limitations, such as safety and stability issues, for implementing preventive and therapeutic strategies based on dietary compounds in ObOA patients.