Proliferation of rabbit chondrocyte and inhibition of IL-1β-induced apoptosis through MEK/ERK signaling by statins

Comprehensive multi-omics approach reveals potential therapeutic targets and agents for osteoarthritis

BACKGROUND

The mechanisms underlying osteoarthritis (OA) remain unclear, and effective treatments are lacking. This study aims to identify OA-related genes and explore their potential in drug repositioning for OA treatment.

METHODS

Transcriptome-wide association studies (TWAS) were performed using genome-wide association studies summary data and expression quantitative trait loci data from the Genotype-Tissue Expression project. Differentially expressed genes between OA patients and healthy controls were identified using four datasets from the Gene Expression Omnibus database. Gene ontology and pathway enrichment analyses identified potential hub genes associated with OA. A network-based drug repositioning approach was applied to discover potential therapeutic drugs for OA.

RESULTS

Through TWAS and mRNA expression profiling, 7 and 167 OA-related genes were identified, respectively. From these, 128 OA-related genes were selected based on common biological processes. Using the maximal clique centrality algorithm, 10 core-related genes (JUN, VEGFA, FN1, CD44, PTGS2, STAT1, MAP 2K7, GRB2, EP300, and PXN) were identified for network-based drug repositioning. Consequently, 24 drugs were identified based on 128 OA-related genes and 23 drugs based on 10 core OA-related genes. Some identified drugs, such as dexamethasone, menadione, and hyaluronic acid, have been previously reported for OA and/or rheumatoid arthritis treatment. Network analysis also indicated that spironolactone, lovastatin, and atorvastatin may have potential in OA treatment.

CONCLUSION

This study identified potential OA-related genes and explored their roles in drug repositioning, suggesting the repurposing of existing drugs and the development of new therapeutic options for OA patients. Key message What is already known on this topic The exact pathogenesis of osteoarthritis (OA) remains unclear, and currently, there are no approved drugs that can prevent, halt, or inhibit the progression of OA. What this study adds We identified 128 OA-related genes and 10 core-related genes based on common biological processes revealed by TWAS and mRNA expression profiling. Using these genes, we discovered potential drugs for OA through the Network-based drug repositioning method. How this study might affect research, practice, or policy This study provides recommendations for repositioning existing drugs and developing new treatment options for patients with OA.

Potential Benefits of Statin Therapy in Reducing Osteoarthritis Risk: A Mendelian Randomization Study

OBJECTIVE

The purpose of this study was to determine the causal effect of statins on osteoarthritis (OA) risk using Mendelian randomization (MR).

METHODS

Single nucleotide polymorphism-based genome-wide association analyses of statins were collected from the UK Biobank and FinnGen dataset, and OA data were collected from the UK Biobank and Arthritis Research UK Osteoarthritis Genetics (arcOGEN) study. Two-sample MR analyses were performed using the inverse-variance weighted (IVW) technique. MR-Egger, weighted median, and weighted mode served as supplementary analyses. MR-Egger regression, Cochran's Q test, and Mendelian Randomization Pleiotropy Residual Sum and Outlier analysis were performed as sensitivity analyses. Hydroxymethylglutaryl-coenzyme A reductase (HMGCR) expression and OA risk were evaluated using summary data-based MR (SMR).

RESULTS

MR analyses consistently supported a causal connection between statin use and OA risk. A causal effect was observed for atorvastatin (IVW: β = -2.989, P = 0.003) and rosuvastatin (IVW: β = -14.141, P = 0.006) treatment on hip OA. Meta-analysis showed the association between atorvastatin and knee OA was statistically significant (odds ratio 0.15; P = 0.004). Simvastatin use exhibited a protective effect against knee (IVW: β = -1.056, P = 0.004) and hip OA (IVW: β = -1.405, P = 0.001). Statin medication showed a protective effect on hip OA (IVW: β = -0.054, P = 0.013). HMGCR correlated significantly with a reduced risk of knee OA (β = -0.193, PSMR = 0.017), rather than hip OA (β = 0.067, PSMR = 0.502), which suggested that statins' protective effect on OA may not be related to its lipid-lowering effect.

CONCLUSION

This MR study provides compelling evidence that statin treatment may be a protective factor for OA. Further research is required to clarify its underlying mechanism.

Risk of metabolic abnormalities in osteoarthritis: a new perspective to understand its pathological mechanisms

Although aging has traditionally been viewed as the most important risk factor for osteoarthritis (OA), an increasing amount of epidemiological evidence has highlighted the association between metabolic abnormalities and OA, particularly in younger individuals. Metabolic abnormalities, such as obesity and type II diabetes, are strongly linked to OA, and they affect both weight-bearing and non-weight-bearing joints, thus suggesting that the pathogenesis of OA is more complicated than the mechanical stress induced by overweight. This review aims to explore the recent advances in research on the relationship between metabolic abnormalities and OA risk, including the impact of abnormal glucose and lipid metabolism, the potential pathogenesis and targeted therapeutic strategies.

Anti-inflammatory and Chondroprotective Effects of Platelet-derived Growth Factor-BB on Osteoarthritis Rat Models

Osteoarthritis (OA) is a common and challenging joint disease that mainly affects the diarthrodial joints. Traditionally, except for surgery for severe cases, treatments for OA mainly focus on relieving pain and improving joint function. However, these treatments are not effective for cartilage repair and induce only symptomatic relief. Platelet-derived growth factor (PDGF)-BB, a member of the PDGF cytokine family, has been proved to have effects on protecting the chondrocytes via multiple mechanisms. In this study, we further focused on the effects of PDGF-BB on OA and found that PDGF-BB could attenuate OA development by inhibiting inflammation and enhancing cell proliferation via JAK2/STAT3, PI3K/AKT, and p38 signaling pathways and PKA-mediated regulation of SOX-9/RunX-2. This article demonstrates the feasibility of PDGF-BB application as a treatment for OA. This is the first article that reports that PDGF-BB attenuates OA development via PKA-mediated regulation of SOX-9 and RunX-2.

Role of signal transduction pathways in IL-1β-induced apoptosis: Pathological and therapeutic aspects

BACKGROUND

Interleukin-1β (IL-1β) is a pro-inflammatory cytokine mainly produced by monocytes and macrophages with a wide range of biological effects. Evidence has shown that IL-1β plays a vital role in the process of apoptosis; however, the specific mechanisms, by which IL-1β induces apoptosis, vary due to different cellular and experimental conditions. Therefore, this present reviewstudy aimed to systematically review the association between the molecular mechanisms of IL-1β-induced apoptosis in pathological processes and the role of signaling pathways. This article also sought to briefly investigate the potential of signaling pathway-targeted therapy in the prevention and treatment of disease.

METHODS

This is a literature review article. The present discourse aim is first to scrutinize and assess the available literature on IL-1β and apoptosis. The relevant studies using the keywords of "IL-1β-induced apoptosis" and "signaling pathways" were searched in the databases of PubMed, Scopus, Google Scholar, and Web of Science. Gathered relevant material, and extracted information was then assessed.

RESULTS

IL-1β can induce apoptosis in various types of cells under different external stimuli via the mitochondrial pathway, death receptor pathway and endoplasmic reticulum pathway, and that the different pathways are often interconnected. The NF-kB signaling pathway, p38MAPK, and JNK signaling pathways mainly play a proapoptotic part, and the ERK1/2 pathway has a bidirectional role in regulating apoptosis, while activation of the PI3K-Akt signaling pathway can inhibit apoptosis.

CONCLUSION

This review indicates that IL-1β-induced apoptosis plays an important role in pathogenesis and development of pathology of many inflammatory diseases. Elucidating the role of the signaling pathways will aid the development of targeted therapeutic treatments.

3D Printing for Bone-Cartilage Interface Regeneration

Due to the vasculature defects and/or the avascular nature of cartilage, as well as the complex gradients for bone-cartilage interface regeneration and the layered zonal architecture, self-repair of cartilage and subchondral bone is challenging. Currently, the primary osteochondral defect treatment strategies, including artificial joint replacement and autologous and allogeneic bone graft, are limited by their ability to simply repair, rather than induce regeneration of tissues. Meanwhile, over the past two decades, three-dimension (3D) printing technology has achieved admirable advancements in bone and cartilage reconstruction, providing a new strategy for restoring joint function. The advantages of 3D printing hybrid materials include rapid and accurate molding, as well as personalized therapy. However, certain challenges also exist. For instance, 3D printing technology for osteochondral reconstruction must simulate the histological structure of cartilage and subchondral bone, thus, it is necessary to determine the optimal bioink concentrations to maintain mechanical strength and cell viability, while also identifying biomaterials with dual bioactivities capable of simultaneously regenerating cartilage. The study showed that the regeneration of bone-cartilage interface is crucial for the repair of osteochondral defect. In this review, we focus on the significant progress and application of 3D printing technology for bone-cartilage interface regeneration, while also expounding the potential prospects for 3D printing technology and highlighting some of the most significant challenges currently facing this field.

Linagliptin ameliorated interleukin-29-induced reduction of extracellular matrix genes through the nuclear factor erythroid 2-related factor 2 (Nrf2)/sry-type high-mobility-group box (SOX)-9 axis in an in vitro study on C-28/I2 chondrocytes

Osteoarthritis (OA) is a severe orthopedic disease commonly observed in the elderly population and is closely related to the degradation of extracellular matrix (ECM) in cartilage tissues. Interleukin-29 (IL-29) is a cytokine that has been recently linked with the progression of OA. However, the physiological roles of IL-29 in ECM genes and function are unknown. Linagliptin is a novel dipeptidyl peptidase-4 (DPP-4) inhibitor recently reported to exert significant anti-inflammatory properties. In this study, we used IL-29 to stimulate C-28/I2 chondrocytes to build an inflammatory injury model. We aimed to investigate the protective effect of Linagliptin on IL-29-induced degradation of ECM. We found that IL-29 stimulation reduced the expressions of Col2a1 and Acan in C-28/I2 chondrocytes, and this effect was mediated by SRY-related high-mobility group box gene-9 (SOX-9), as we showed that overexpression of SOX-9 could rescue the reduction of Col2a1 and Acan. Interestingly, we found that IL-29 stimulation pronouncedly promoted the expression of DPP-4. Treatment with 100 nM of the DPP-4 inhibitor Linagliptin ameliorated IL-29-induced expressions of SOX-9, Col2a1, and Acan. Lastly, the nuclear level of nuclear factor erythroid 2-related factor 2 (Nrf2) was dramatically declined in IL-29-challenged chondrocytes and the protective effects of Linagliptin on the expressions of SOX-9, Col2a1, and Acan were abolished by the knockdown of Nrf2. Taken together, our data reveal that Linagliptin ameliorated IL-29-induced reduction of ECM genes partially through the Nrf2/SOX-9 axis in C-28/I2 chondrocytes. Further in vivo and clinical studies will be done to clarify the protective benefits of Linagliptin in OA.

Effect of high fat diet and excessive compressive mechanical force on pathologic changes of temporomandibular joint

The aim of this study was to investigate the effect of high fat diet and excessive compressive mechanical force on temporomandibular joint. In vivo, a mouse model of temporomandibular joint compressive loading device was used. A high fat diet mouse model and a combined mouse model intraperitoneally treated with or without simvastatin were used in the study. The pathological changes of mandibular condylar cartilage were assessed by Safranin-O staining. The IL-1β, MMP-3, leptin expression changes in the cartilage were detected by immunohistochemistry. In vitro, the mandibular condylar chondrocytes were treated with or without L-1β and simvastatin. The mRNA expression level of matrix MMPs and leptin were assessed. Both excessive compressive mechanical force and high fat diet induced obesity caused TMJ osteoarthritis-like changes and increased expression of IL-1β, MMP-3, and leptin. These pathological changes were much more serious when the two interventions were exerted together, while simvastatin could obviously alleviate these changes. The mRNA expression of MMP-3, MMP-13, and leptin increased in the IL-1β treated chondrocytes treated with IL-1β, and decreased with simvastatin treatment. The development of temporomandibular joint pathological changes could be caused by the excessive compressive mechanical force and high fat diet induced obesity.

Vitamin D3 protects articular cartilage by inhibiting the Wnt/β-catenin signaling pathway

Low expression levels of 25-hydroxyvitamin D (vitamin D3) in the blood have been reported to be associated with the progression of osteoarthritis; however, the mechanisms by which this occurs remain unclear. The present study aimed to determine the effects of vitamin D3 on chondrocytes. MTT assays were used to determine whether vitamin D3 affects chondrocytes viability. Primary chondrocytes were treated with control culture medium, vitamin D3, tumor necrosis factor (TNF)-α, TNF-α + PNU-74654 [Wingless-related integration site (Wnt)/β-catenin signaling pathway inhibitor] or TNF-α + vitamin D3. Reverse transcription-quantitative PCR and western blotting were utilized to measure the gene and protein expression of collagen II, aggrecan, matrix metalloproteinase (MMP)-3 and MMP-13, A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, ADAMTS-5, Wnt-3a and nuclear β-catenin. The results demonstrated that TNF-α reduced the expression levels of aggrecan and collagen II, and increased the expression levels of MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5. Furthermore, vitamin D3 and PNU-74654 were observed to partially attenuate the effects induced by TNF-α. Moreover, similar findings were reported following co-treatment with vitamin D3 and TNF-α. Western blotting data revealed that TNF-α increased Wnt-3a and β-catenin protein levels in chondrocytes, while Vitamin D3 and PNU-74654 decreased the expression levels of Wnt-3a and nuclear β-catenin. In conclusion, the findings of the present study provided evidence to suggest that vitamin D3 may prevent articular cartilage degeneration and osteoarthritic disease progression by inhibiting the expression levels of MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5 through suppressing the Wnt/β-catenin signaling pathway. These results suggested that vitamin D3 may be of therapeutic value for the prevention and treatment of osteoarthritis.

Plant homeodomain finger protein 23 inhibits autophagy and promotes apoptosis of chondrocytes in osteoarthritis

BACKGROUND

Plant homeodomain finger protein 23 (PHF23) is a novel autophagy inhibitor gene that has been few studied with respect to orthopedics. This study was to investigate the expression of PHF23 in articular cartilage and synovial tissue, and analyze the relationship between PHF23 and chondrocyte autophagy in osteoarthritis (OA).

METHODS

Immunohistochemical staining and western blot were applied to show the expression of PHF23 in cartilage of different outbridge grades and synovial tissue of patient with OA and healthy control. The normal human chondrocyte pre-treated with rapamycin or 3-methyladenine, treated with interleukin-1β (IL-1β). IL-1β induced expression level of PHF23 and autophagy-related proteins light chain 3B-I (LC3B-I), LC3B-II, and P62, were examined by Western blot. A PHF23 gene knock-down model was constructed with small interfering RNA. Western blot was performed to detect the efficiency of PHF23 and the impact of PHF23 knockout on IL-1β-induced expression of autophagy-related and apoptotic-related proteins in chondrocyte.

RESULTS

The expression of PHF23 was significantly increased in the high-grade cartilage and synovial tissue of patients with OA. The IL-1β-induced expression of PHF23 was gradually enhanced with time. The level of LC3B-II, P62 changed with time. After knockdown of PHF23, the level of autophagy-related proteins increased and apoptotic-related proteins decreased in IL-1β-induced OA-like chondrocytes.

CONCLUSIONS

The expression of PHF23 increased in human OA cartilage and synovium, and was induced by IL-1β through inflammatory stress. PHF23 can suppress autophagy of chondrocytes, and accelerate apoptosis.

[Mechanical stress promotes cartilage repair in inflammatory environment]

OBJECTIVE

To investigate the effect and mechanism of mechanical stress on cartilage repair in inflammatory environment.

METHODS

The chondrogenic progenitor cells (CPCs) were isolated from the knee joint cartilage of patients with osteoarthritis (OA) undergoing total knee arthroplasty. The CPCs were cultured and expanded in a 3-D scaffold constructed with alginate. Intermittent hydrostatic pressure (IHP) was applied in a inflammatory environment induced by IL-1β, and Western blot was used to detect the expression of MAPK signaling pathway proteins. Cell proliferation was detected by CCK-8 method, and the expression of related genes like matrix metallo-proteinases 13 (MMP-13) and a disintegrins and metalloproteinase with thrombospondin motif 5 (ADAMTS-5) was detected by real-time RT-PCR. The anterior cruciate ligament of the rats was cut to construct the knee joint OA model, and the appropriate mechanical stress was constructed with external fixation to distract the knee joint in order to observe the repair of the cartilage and to explore its mechanism.

RESULTS

Adding 0.01 ng/ml IL-1β in cell culture inhibited the proliferation of CPCs. After IHP application, the expression of MAPK pathway protein was decreased, the mRNA expression of MMP-13 and ADAMTS-5 was reduced. The inhibition of IL-1β on CPCs was counteracted by IHP. Four weeks after the anterior cruciate ligament resected, the articular cartilage degeneration was observed in rats. The Mankin score in the OA treatment (joint distraction) group was lower, and the cartilage repair was better than that of the control group (P<0.01). Animal experiments found that the suitable mechanical stress reduced the expression of P-p38, MMP-13 and COLL-X, inhibited cartilage cells apoptosis and promoted the repair of OA cartilage.

CONCLUSIONS

Mechanical stress can promote the proliferation of CPCs, reduce the expression of matrix degrading enzymes, and promote the repair of OA cartilage by inhibiting MAPK signaling pathway.

Understanding Articular Cartilage Injury and Potential Treatments

The goals of all orthopaedic surgeons treating articular cartilage injuries have been anatomic reduction and stable fixation of the articular cartilage surface with restoration of limb alignment and/or reestablishment of the joint stability, all while minimizing the risk of surgical complications. Recent developments in the study of articular cartilage injury have shown that there is a robust cellular response to joint injury. This response has been shown to involve the synoviocytes, chondrocytes, and osteocytes in and around the injured joint and if these responses are left unchecked, they can lead to the development of posttraumatic osteoarthritis (PTOA). Therefore, to predictably and successfully treat articular cartilage injuries, it is not sufficient to just restore articular congruity, limb alignment, and joint stability, but we must also recognize and attempt to mitigate this associated cellular response. Understanding not only the mechanical aspects of these joint injuries but also the biological aspects is paramount to giving our patients the best opportunity to heal their injuries, recover full function, and avoid the potential devastating development of PTOA. Gone is the simplistic view that if one can achieve articular congruity after intraarticular fracture, as well as joint stability after ligamentous injury, that our patients will do just fine. This review sheds new light on the molecular response to cartilage injury, how residual joint incongruity and instability affect the joint's ability to recover from injury, and how chondrocyte apoptosis in response to injury can influence joint. This article then briefly reviews how cellular and growth factors may be beneficial to the treatment of articular cartilage injury and how ultimately cartilage regeneration may be used in the future to salvage the joints ravaged by PTOA in response to injury.

Qing Chang Hua Shi granule ameliorate inflammation in experimental rats and cell model of ulcerative colitis through MEK/ERK signaling pathway

Ulcerative colitis (UC), a bowel disease with significant morbidity, is associated with inflammation. In this study, the effect of Qingchang Huashi granule (QCHS) on UC and its underlying mechanisms were explored using both animal and cell culture experiments. A rat UC model was induced with trinitro-benzene-sulfonic acid (TNBS), concentrations of the cytokines IL-1α, IL-6, IL-8, IL-1β, and TNF-α were significantly up-regulated and the concentrations of IL-4, IL-10, and IL-13 were significantly down-regulated compared with the control group (P < 0.05). In contrast, the QCHS and salicylazosulfapyridine (SASP) groups reversed these modulations (P < 0.05). A UC cell model in HT-29 cells was generated using TNF-α combined with lipopolysaccharide treatment. Cells treated with QCHS were used to investigate the possible mechanisms. The expression of apoptosis-related proteins, including Bax/Bcl-2, caspase-3, caspase-9, Fas/Fas-L, and Rafl in the QCHS and SASP groups, were significantly lower than that in the control group in both animal and cell experiments (P < 0.05). In addition, the in vitro results indicate changes in these indicators mediate the MEK/ERK signaling pathways via SGK1. Our results suggested that QCHS could be beneficial in preventing UC progression as an alternative drug for UC treatment.

Interleukin-1β induces apoptosis in annulus fibrosus cells through the extracellular signal-regulated kinase pathway

PURPOSE

The loss of intervertebral disc (IVD) cells due to excessive apoptosis induced by inflammatory cytokines is a major cause of IVD degeneration. This study aims to explore the mechanism of interleukin-1β (IL-1β)-induced apoptosis of annulus fibrosus cells (AFCs). It's hypothesized that IL-1β induces apoptosis through the extracellular signal-regulated kinase (ERK) pathway in AFCs.

METHODS

The mRNA and protein expression levels of apoptosis-associated genes were analyzed by quantitative real-time PCR and Western blotting. The apoptotic rate was measured by flow cytometry. Three experimental groups were established, including Control, IL-1β, and IL-1β+U0126 groups, respectively.

RESULTS

Increase in the expression of apoptosis-associated genes including B-cell lymphoma-2 associated X (Bax), caspase-3, and caspase-9, and meanwhile, decrease in the expression of B-cell lymphoma-2 (Bcl-2) gene were found in patients with degenerative IVDs. In in vitro tests, both apoptosis and phosphorylated ERK expression in rat AFCs decreased in the IL-1β+U0126 group compared with the IL-1β group. The expression levels of Bax, caspase-3, and caspase-9 in AFCs decreased significantly in the IL-1β+U0126 group compared with those in the IL-1β group. The expression level of Bcl-2, on the other hand, significantly increased.

CONCLUSIONS

Findings from this study suggest that IL-1β induces apoptosis in AFCs through the ERK pathway, and therefore, ERK inhibition may provide certain protection against the adverse effects of IL-1β.

Interleukin-1β signaling in osteoarthritis - chondrocytes in focus

Osteoarthritis (OA) can be regarded as a chronic, painful and degenerative disease that affects all tissues of a joint and one of the major endpoints being loss of articular cartilage. In most cases, OA is associated with a variable degree of synovial inflammation. A variety of different cell types including chondrocytes, synovial fibroblasts, adipocytes, osteoblasts and osteoclasts as well as stem and immune cells are involved in catabolic and inflammatory processes but also in attempts to counteract the cartilage loss. At the molecular level, these changes are regulated by a complex network of proteolytic enzymes, chemokines and cytokines (for review: [1]). Here, interleukin-1 signaling (IL-1) plays a central role and its effects on the different cell types involved in OA are discussed in this review with a special focus on the chondrocyte.

Modulation of cartilage's response to injury: Can chondrocyte apoptosis be reversed?

Osteoarthritis is characterized by a chronic, progressive and irreversible degradation of the articular cartilage associated with joint inflammation and a reparative bone response. More than 100 million people are affected by this condition worldwide with significant health and welfare costs. Our available treatment options in osteoarthritis are extremely limited. Chondral or osteochondral grafts have shown some promising results but joint replacement surgery is by far the most common therapeutic approach. The difficulty lies on the limited regeneration capacity of the articular cartilage, poor blood supply and the paucity of resident progenitor stem cells. In addition, our poor understanding of the molecular signalling pathways involved in the senescence and apoptosis of chondrocytes is a major factor restricting further progress in the area. This review focuses on molecules and approaches that can be implemented to delay or even rescue chondrocyte apoptosis. Ways of modulating the physiologic response to trauma preventing chondrocyte death are proposed. The use of several cytokines, growth factors and advances made in altering several of the degenerative genetic pathways involved in chondrocyte apoptosis and degradation are also presented. The suggested approaches can help clinicians to improve cartilage tissue regeneration.