Inhibition of histone lysine demethylase 6A promotes chondrocytic activity and attenuates osteoarthritis development through repressing H3K27me3 enhancement of Wnt10a

Therapeutic potential of SOX family transcription factors in osteoarthritis

BACKGROUND

As the worldwide population ages, osteoarthritis has significantly increased. This musculoskeletal condition has become a pressing global health issue and thus, prevention and treatment of osteoarthritis have become the primary focus of domestic and international research. Scholarly investigations of the molecular mechanisms that are related to the occurrence and development of osteoarthritis have shed light on the pathological causes of this condition to a certain extent, providing a foundation for its prevention and treatment. However, further research is necessary to fully understand the critical role of the transcription factor SOX9 in chondrocyte differentiation and the development of osteoarthritis. As a result, there has been widespread interest in SOX transcription factors. While SOX9 has been utilized as a biomarker to indicate the occurrence and prognosis of osteoarthritis, investigations into other members of the SOX family and the development of targeted treatments around SOX9 are still required.

PURPOSE

This article considers the impact of the SOX protein on the development and inhibition of osteoarthritis and highlights the need for therapeutic approaches targeting SOX9, as supported by existing research.

RESULTS

SOX9 can contribute to the process of osteoarthritis through acetylation and ubiquitination modifications. The regulation of the WNT signalling pathway, Nrf2/ARE signalling pathway, NF-κB signalling pathway and SOX9 is implicated in the emergence of osteoarthritis. Non-coding RNA may play a role in the onset and progression of osteoarthritis by modulating various SOX family members, including SOX2, SOX4, SOX5, SOX6, SOX8, SOX9 and SOX11.

CONCLUSION

SOX9 has the capability of mitigating the onset and progression of osteoarthritis through means such as medication therapy, stem cell therapy, recombinant adeno-associated virus (rAAV) vector therapy, physical therapy and other approaches.

Exploring the Analgesic Potential of L-Lysine: Molecular Mechanisms, Preclinical Evidence, and Implications for Pharmaceutical Pain Therapy

Pain is a complex, multifaceted sensory-emotional state. It still poses a significant challenge in clinical treatment, especially in cases of chronic pain. Concerns associated with the use of opioids as analgesics have led to the search for new and safer pain relievers. This review examines the potential of lysine in pain control by exploring its molecular mechanisms and the preclinical evidence and clinical implications. Lysine has demonstrated analgesic effects by inhibiting NMDA receptors, modulating dopamine and serotonin pathways, and interfering with neuroimmune signaling cascades. Studies in animal models have shown that the administration of lysine reduces pain responses without altering motor function. Despite the favorable profile of lysine in terms of minor side effects and its promising effectiveness as a nutritional supplement, more research is needed to optimize its efficacy, adjust its dosage, and ensure its safety for long-term use.

Insights into the role of histone lysine demethylases in bone homeostasis and skeletal diseases: A review

Histone lysine demethylases (KDMs), as important epigenetic regulators, are involved in various biological processes such as energy metabolism, apoptosis, and autophagy. Recent research shows that KDMs activate or silence downstream target genes by removing lysine residues from histone tails, and participate in the regulation of bone marrow mesenchymal stem cells (BM-MSCs), osteoblasts (OB), osteoclasts (OC), chondrocytes and other skeletal cell development, differentiation and formation. Moreover, several members of the KDM family affect the occurrence and development of bone diseases such as osteoporosis (OP), osteoarthritis (OA), osteosarcoma (OS), by regulating target genes. Specific regulation mechanisms of KDMs suggest new strategies for bone disease treatment and prevention. Despite the unique function and importance of KDMs in the skeletal system, previous studies have never systematically summarized their specific role, molecular mechanism, and clinical treatment in bone physiology and pathology. Therefore, this review summarises the expression pattern, intracellular signal transduction, and mechanism of action of the KDM family in several bone physiological and pathological conditions, aiming to highlight the important role of KDMs in bone diseases and provide a reference for the future treatment of bone diseases.

Selective Modulation of Osteoclast Function by Bothrops moojeni Venom and Its Fractions: Implications for Therapeutic Targeting in Bone Diseases

Our study explores the differential effects of Bothrops moojeni venom and its fractions on osteoclast (OC) morphology, function, and osteoclastogenesis. The crude venom and its high-molecular-weight (HMW) fraction disrupt critical OC processes, including F-actin ring formation and mitochondrial distribution, thereby impairing bone resorption. These components primarily target cytoskeletal integrity and transcription regulation, with the OBSCN gene playing a direct role in OC function. In contrast, the low-molecular-weight (LMW) fraction selectively modulates OCs without significant cytoskeletal alterations. It influences vital cellular signaling pathways, notably through FNIP1 and FNIP2, essential for OC differentiation and function. This suggests a more targeted therapeutic approach with potentially fewer off-target effects. The venom also alters cytokine production, increasing IL-6 and IL-10 levels. Elevated IL-6 levels promote osteoclastogenesis and bone resorption, while IL-10 appears to counterbalance these effects through a regulatory feedback mechanism. Secretome analysis reveals that the crude venom and HMW fraction disrupt proteins involved in membrane trafficking and structural integrity. In contrast, the LMW fraction influences matrix remodeling, energy metabolism, and gene regulation. Gene interaction analysis LMW fraction post-treatment identifies FNIP1 and FNIP2 as critical targets involved in osteoclastogenesis. The observed changes in gene expression, including those related to immune response, energy metabolism, and chromatin remodeling, provide insights into the venom's impact on bone health. Overall, the LMW fraction shows promise for drug development due to its selective implications and potential for fewer side effects, offering a more precise approach to treating bone diseases.

Curcumenol regulates Histone H3K27me3 demethylases KDM6B affecting Succinic acid metabolism to alleviate cartilage degeneration in knee osteoarthritis

BACKGROUND

Cartilage metabolism dysregulation is a crucial driver in knee osteoarthritis (KOA). Modulating the homeostasis can mitigate the cartilage degeneration in KOA. Curcumenol, derived from traditional Chinese medicine Curcuma Longa L., has demonstrated potential in enhancing chondrocyte proliferation and reducing apoptosis. However, the specific mechanism of Curcumenol in treating KOA remains unclear. This study aimed to demonstrate the molecular mechanism of Curcumenol in treating KOA based on the transcriptomics and metabolomics, and both in vivo and in vitro experimental validations.

MATERIALS AND METHODS

In this study, a destabilization medial meniscus (DMM)-induced KOA mouse model was established. And the mice were intraperitoneally injected with Curcumenol at 4 and 8 mg/kg concentrations. The effects of Curcumenol on KOA cartilage and subchondral was evaluated using micro-CT, histopathology, and immunohistochemistry (IHC). In vitro, OA chondrocytes were induced with 10 μg/mL lipopolysaccharide (LPS) and treated with Curcumenol to evaluate the proliferation, apoptosis, and extracellular matrix (ECM) metabolism through CCK8 assay, flow cytometry, and chondrocyte staining. Furthermore, transcriptomics and metabolomics were utilized to identify differentially expressed genes (DEGs) and metabolites. Finally, integrating multi-omics analysis, virtual molecular docking (VMD), and molecular dynamics simulation (MDS), IHC, immunofluorescence (IF), PCR, and Western blot (WB) validation were conducted to elucidate the mechanism by which Curcumenol ameliorates KOA cartilage degeneration.

RESULTS

Curcumenol ameliorated cartilage destruction and subchondral bone loss in KOA mice, promoted cartilage repair, upregulated the expression of COL2 while downregulated MMP3, and improved ECM synthesis metabolism. Additionally, Curcumenol also alleviated the damage of LPS on the proliferation activity and suppressed apoptosis, promoted ECM synthesis. Transcriptomic analysis combined with weighted gene co-expression network analysis (WGCNA) identified a significant downregulation of 19 key genes in KOA. Metabolomic profiling showed that Curcumenol downregulates the expression of d-Alanyl-d-alanine, 17a-Estradiol, Glutathione, and Succinic acid, while upregulating Sterculic acid and Azelaic acid. The integrated multi-omics analysis suggested that Curcumenol targeted KDM6B to regulate downstream protein H3K27me3 expression, which inhibited methylation at the histone H3K27, consequently reducing Succinic acid levels and improving KOA cartilage metabolism homeostasis. Finally, both in vivo and in vitro findings indicated that Curcumenol upregulated KDM6B, suppressed H3K27me3 expression, and stimulated collagen II expression and ECM synthesis, thus maintaining cartilage metabolism homeostasis and alleviating KOA cartilage degeneration.

CONCLUSION

Curcumenol promotes cartilage repair and ameliorates cartilage degeneration in KOA by upregulating KDM6B expression, thereby reducing H3K27 methylation and downregulating Succinic Acid, restoring metabolic stability and ECM synthesis.

Histone demethylase PHF8 protected against chondrocyte injury and alleviated posttraumatic osteoarthritis by epigenetically enhancing WWP2 expression

Aberrant mechanical forces were considered as an important factor for osteoarthritis (OA) pathogenesis. Plant homeodomain finger-containing protein 8 (PHF8) participated in osteogenic differentiation and inflammatory progression. However, the role of PHF8 in aberrant force-related OA remains to be elucidated. In this study, a fluid shear stress (FSS) model in ATDC5 cells and an anterior cruciate ligament transection (ACLT) animal model were constructed. The results revealed the decrease of PHF8 in aberrant force-induced cartilage damage in vitro and in vivo. PHF8 overexpression alleviated the aberrant force-induced cell apoptosis, extracellular matrix degradation, and inflammation. Chromatin immunoprecipitation (ChIP) assays demonstrated that PHF8 epigenetically regulated WWP2 expression through demethylating H3K9me2 at WWP2 promoter, which was influenced by FSS treatment. C-X-C chemokine receptor type 4 (CXCR4) was identified as a potential substrate of WWP2. Co-immunoprecipitation (Co-IP) and ubiquitination experiments further demonstrated WWP2 decreased the stability of CXCR4 via the ubiquitination pathway. Subsequently, rescue experiments validated reintroduction of WWP2 significantly attenuated the effects of PHF8 deletion on FSS-induced chondrocyte injury, and CXCR4 overexpression reversed the protective effects of WWP2 overexpression on chondrocyte injury in FSS-treated ATDC5 cells. Moreover, delivery of a PHF8 adeno-associated virus (AAV) into articular cartilage remarkably ameliorated the breakdown of cartilage matrix by ACLT in mice. In conclusion, our findings highlighted the importance of PHF8/WWP2/CXCR4 signaling pathway in aberrant force-induced cartilage injury, which might provide a novel insight on future epigenetic-based treatment of posttraumatic OA.

The Role of Genetics and Epigenetic Regulation in the Pathogenesis of Osteoarthritis

Osteoarthritis (OA) is progressive disease characterised by cartilage degradation, subchondral bone remodelling and inflammation of the synovium. The disease is associated with obesity, mechanical load and age. However, multiple pro-inflammatory immune mediators regulate the expression of metalloproteinases, which take part in cartilage degradation. Furthermore, genetic factors also contribute to OA susceptibility. Recent studies have highlighted that epigenetic mechanisms may regulate the expression of OA-associated genes. This review aims to present the mechanisms of OA pathogenesis and summarise current evidence regarding the role of genetics and epigenetics in this process.

The role of epigenetic modifications in sensory hair cell development, survival, and regulation

The cochlea is the sensory organ in the periphery, and hair cells are its main sensory cells. The development and survival of hair cells are highly controlled processes. When cells face intracellular and environmental stimuli, epigenetic regulation controls the structure and function of the genome in response to different cell fates. During sensory hair cell development, different histone modifications can induce normal numbers of functional hair cells to generate. When individuals are exposed to environmental-related hair cell damage, epigenetic modification also plays a significant role in the regulation of hair cell fate. Since mammalian hair cells cannot regenerate, their loss can cause permanent sensorineural hearing loss. Many breakthroughs have been achieved in recent years in understanding the signaling pathways that determine hair cell regeneration, and it is fascinating to note that epigenetic regulation plays a significant role in hair cell regeneration. In this review, we discuss the role of epigenetics in inner ear cell development, survival and regeneration and the significant impact on hearing protection.