Quantitative analysis of the mRNA expression levels of BCL2 and BAX genes in human osteoarthritis and normal articular cartilage: An investigation into their differential expression

Response of Articular Cartilage to Hyperosmolar Stress: Report of an Ex Vivo Injury Model

BACKGROUND

Physiological 0.9% saline is commonly used as an irrigation fluid in modern arthroscopy. There is a growing body of evidence that a hyperosmolar saline solution has chondroprotective effects, especially if iatrogenic injury occurs.

PURPOSE

To (1) corroborate the superiority of a hyperosmolar saline solution regarding chondrocyte survival after mechanical injury and (2) observe the modulatory response of articular cartilage to osmotic stress and injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Osteochondral explants were isolated from bovine stifle joints and exposed to either 0.9% saline (308 mOsm) or hyperosmolar saline (600 mOsm) and then damaged with a sharp dermatome blade to attain a confined full-thickness cartilage injury site, incubated in the same fluids for another 3 hours, and transferred to chondropermissive medium for further culture for 1 week. Chondrocyte survival was assessed by confocal imaging, while the cellular response was evaluated over 1 week by relative gene expression for apoptotic and inflammatory markers and mediator release into the medium.

RESULTS

The full-thickness cartilage cut resulted in a confined zone of cell death that mainly affected superficial zone chondrocytes. Injured samples that were exposed to hyperosmolar saline showed less expansion of cell death in both the axial (P < .007) and the coronal (P < .004) plane. There was no progression of cell death during the following week of culture. Histological assessment revealed an intact cartilage matrix and normal chondrocyte morphology. Inflammatory and proapoptotic genes were upregulated on the first days postexposure with a notable downregulation toward day 7. Mediator release into the medium was concentrated on day 3.

CONCLUSION

This in vitro cartilage injury model provides further evidence for the chondroprotective effect of a hyperosmolar saline irrigation fluid, as well as novel data on the capability of articular cartilage to quickly regain joint homeostasis after osmotic stress and injury.

CLINICAL RELEVANCE

Raising the osmolarity of an irrigating solution may be a simple and safe strategy to protect articular cartilage during arthroscopic surgery.

MSRB2 Ameliorates H2O2-induced Chondrocyte Oxidative Stress and Suppresses Apoptosis in Osteoarthritis

BACKGROUND

Chondrocyte oxidative stress and apoptosis are critical factors contributing to the pathogenesis of osteoarthritis (OA). Methionine sulfoxide reductase B2 (MSRB2) is a mitochondrial protein that protects cells from oxidative stress and is involved in apoptosis. This study aimed to investigated the expression of MSRB2 in articular cartilage tissues and elucidated its effect on H2O2-stimulated chondrocytes.

METHODS

Human chondrocytes were cultured in Dulbecco's modified Eagle's medium (DMEM)/F12. MSRB2 overexpression in chondrocytes was achieved by transfecting with an MSRB2 overexpression plasmid. Western blot, quantitative RT-PCR, Immunofluorescence staining, and TUNEL assay were employed in this study.

RESULTS

MSRB2 expression was found to be reduced in OA patients. Furthermore, overexpression of MSRB2 in H2O2-induced chondrocytes mitigated apoptosis and enhanced cell viability. Elevated MSRB2 expression diminished chondrocyte ROS contents, decreased cytochrome C (Cyc) in the cytoplasm, and regulated mitochondrial membrane potential to maintain mitochondrial homeostasis. Interestingly, knockdown of charged multivesicular body protein 5 (CHMP5) led to a decreased inMSRB2 expression in chondrocytes. Additionally, protein levels of CHMP5 and MSRB2 were reduced in H2O2-stimulated chondrocytes, and silencing CHMP5 reduced MSRB2 expression. Knockdown of CHMP5 increased cleaved caspase-3 expression in H2O2-induced chondrocytes and elevated TUNEL-positive chondrocytes.

CONCLUSION

MSRB2 decreased in OA, and overexpression of MSRB2 alleviated oxidative stress and apoptosis of chondrocyte.

Anti-proliferative and apoptotic effect of cannabinoids on human pancreatic ductal adenocarcinoma xenograft in BALB/c nude mice model

Human pancreatic ductal adenocarcinoma (PDAC) is a highly malignant and lethal tumor of the exocrine pancreas. Cannabinoids extracted from the hemp plant Cannabis sativa have been suggested as a potential therapeutic agent in several human tumors. However, the anti-tumor effect of cannabinoids on human PDAC is not entirely clarified. In this study, the anti-proliferative and apoptotic effect of cannabinoid solution (THC:CBD at 1:6) at a dose of 1, 5, and 10 mg/kg body weight compared to the negative control (sesame oil) and positive control (5-fluorouracil) was investigated in human PDAC xenograft nude mice model. The findings showed that cannabinoids significantly decreased the mitotic cells and mitotic/apoptotic ratio, meanwhile dramatically increased the apoptotic cells. Parallelly, cannabinoids significantly downregulated Ki-67 and PCNA expression levels. Interestingly, cannabinoids upregulated BAX, BAX/BCL-2 ratio, and Caspase-3, meanwhile, downregulated BCL-2 expression level and could not change Caspase-8 expression level. These findings suggest that cannabinoid solution (THC:CBD at 1:6) could inhibit proliferation and induce apoptosis in human PDAC xenograft models. Cannabinoids, including THC:CBD, should be further studied for use as the potent PDCA therapeutic agent in humans.

Mesenchymal stem cell-derived exosomes as a promising cell-free therapy for knee osteoarthritis

Osteoarthritis (OA), as a degenerative disease, leads to high socioeconomic burdens and disability rates. The knee joint is typically the most affected and is characterized by progressive destruction of articular cartilage, subchondral bone remodeling, osteophyte formation and synovial inflammation. The current management of OA mainly focuses on symptomatic relief and does not help to slow down the advancement of disease. Recently, mesenchymal stem cells (MSCs) and their exosomes have garnered significant attention in regenerative therapy and tissue engineering areas. Preclinical studies have demonstrated that MSC-derived exosomes (MSC-Exos), as bioactive factor carriers, have promising results in cell-free therapy of OA. This study reviewed the application of various MSC-Exos for the OA treatment, along with exploring the potential underlying mechanisms. Moreover, current strategies and future perspectives for the utilization of engineered MSC-Exos, alongside their associated challenges, were also discussed.

Baicalin functionalized PEI-heparin carbon dots as cancer theranostic agent

The worldwide prevalence of cancer and its significantly rising risks with age have garnered the attention of nanotechnology for prompt detection and effective therapy with minimal or no adverse effects. In the current study, heparin (HP) polymer derived heteroatom (N, S-) co-doped CDs were synthesized using hydrothermal synthesis method to efficiently deliver natural anticancer compound baicalin (BA). Heparin carbon dots (HCDs) were passivated with polyethylenimine (PEI) to improve its fluorescence quantum yield. The surface passivation of CDs by polycationic PEI polymer not only facilitated loading of BA, but also played a crucial role in the pH-responsive drug delivery. The sustained release of BA (up to 80 %) in mildly acidic pH (5.5 and 6.5) conditions endorsed its drug delivery potential for cancer-specific microenvironments. BA-loaded PHCDs exhibited enhanced anticancer activity as compared to BA/PHCDs indicating the effectiveness of the nanoformulation, Furthermore, the flow cytometry analysis confirmed that BA-PHCDs treated cells were arrested in the G2/M phase of cell cycle and had a higher potential for apoptosis. Bioimaging study demonstrated the excellent cell penetration efficiency of PHCDs with complete cytoplasmic localization. All this evidence comprehensively demonstrates the potency of BA-loaded PHCDs as a nanotheranostic agent for cancer.

Notopterol alleviates the progression of osteoarthritis: An in vitro and in vivo study

Osteoarthritis (OA) is a prevalent degenerative joint disorder caused by the progressive destruction of cartilage and inflammation in the articular cavity. Studies have proved that the inhibition of articular cartilage destruction and generation of inflammatory factors can be effective strategies for treating OA. Notopterol (NOT) is a quality control index of Notopterygium incisum Ting ex H. T. Chang (N. incisum) with anti-inflammatory, antioxidant, and analgesic activities. Moreover, NOT has been used for many years to treat joint diseases. A study using human C28/I2 cells suggested that NOT down-regulated the hypersecretion of inflammatory mediators and alleviated the degradation of the extracellular matrix (ECM). In addition, NOT decreased the overproduction of reactive oxygen species (ROS) and chondrocyte apoptosis through the nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway. NOT exerted a chondroprotective effect by partly inhibiting the Janus kinase 2/signal transducers and activators of transcription 3 (JAK2/STAT3) and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathways and regulating the nuclear factor Nrf2/heme oxygenase-1(HO-1) signaling pathway. In vivo, NOT improved the destruction of articular cartilage in a rat OA model, which may be related to the inhibition of tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6, and IL-12 expressions in synovial fluid. In summary, these results showed that NOT alleviated the progression of OA and is expected to become a new therapy for treating OA clinically.

Evaluation of enterotoxigenic Bacteroides fragilis correlation with the expression of cellular signaling pathway genes in Iranian patients with colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the most common cancers all over the world, and dysbiosis in the gut microbiota may play a role in colorectal carcinogenesis. Bacteroides fragilis can lead to tumorigenesis by changing signaling pathways, including the WNT/β-catenin pathway. Therefore, in the present study, we investigated the correlation between the enterotoxigenic B. fragilis amount and the expression of signaling pathway genes involved in CRC.

MATERIALS AND METHODS

B. fragilis was determined in 30 tumors and adjacent healthy tissues by the qPCR method. Next, the relationship between enterotoxigenic B. fragilis and the expression of signaling pathway genes, including CCND1, TP53, BCL2, BAX, WNT, TCF, AXIN, APC, and CTNNB1 was investigated. Additionally, possible correlations between clinicopathological features of the tumor samples and the abundance of B. fragilis were analyzed.

RESULTS

The results showed that B. fragilis was detected in 100% of tumor samples and 86% of healthy tissues. Additionally, enterotoxigenic B. fragilis colonized 47% of all samples, and bft-1 toxin was the most frequently found isotype among the samples. The analysis showed that the high level of B. fragilis has a significant relationship with the high expression of AXIN, CTNNB1, and BCL2 genes. On the other hand, our results did not show any possible correlation between this bacterium and the clinicopathological features of the tumor sample.

CONCLUSION

B. fragilis had a higher abundance in the tumor samples than in healthy tissues, and this bacterium may lead to CRC by making changes in cellular signaling pathways and genes. Therefore, to better understand the physiological effects of B. fragilis on the inflammatory response and CRC, future research should focus on dissecting the molecular mechanisms by which this bacterium regulates cellular signaling pathways.

Metformin attenuates symptoms of osteoarthritis: role of genetic diversity of Bcl2 and CXCL16 in OA

OBJECTIVE

This study aimed to evaluate the effectiveness of metformin versus placebo in overweight patients with knee osteoarthritis (OA). In addition, to assess the effects of inflammatory mediators and apoptotic proteins in the pathogenesis of OA, the genetic polymorphisms of two genes, one related to apoptosis (rs2279115 of Bcl-2) and the other related to inflammation (rs2277680 of CXCL-16), were investigated.

METHODS

In this double-blind placebo-controlled clinical trial, patients were randomly divided to two groups, one group receiving metformin (n = 44) and the other one receiving an identical inert placebo (n = 44) for 4 consecutive months (starting dose 0.5 g/day for the first week, increase to 1 g/day for the second week, and further increase to 1.5 g/day for the remaining period). Another group of healthy individuals (n = 92) with no history and diagnosis of OA were included in this study in order to evaluate the role of genetics in OA. The outcome of treatment regimen was evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. The frequency of variants of rs2277680 (A181V) and rs2279115 (938C>A) were determined in extracted DNAs using PCR-RFLP method.

RESULTS

Our results indicated an increase in scores of pain (P ≤ 0.0001), activity of daily living (ADL) (P ≤ 0.0001), sport and recreation (Sport/Rec) (P ≤ 0.0001), and quality of life (QOL) (P = 0.003) and total scores of the KOOS questionnaire in the metformin group compared to the placebo group. Susceptibility to OA was associated with age, gender, family history, CC genotype of 938C>A (Pa = 0.001; OR = 5.2; 95% CI = 2.0-13.7), and GG+GA genotypes of A181V (Pa = 0.04; OR = 2.1; 95% CI = 1.1-10.5). The C allele of 938C>A (Pa = 0.04; OR = 2.2; 95% CI = 1.1-9.8) and G allele of A181V (Pa = 0.02; OR = 2.2; 95% CI = 1.1-4.8) were also associated with OA.

CONCLUSION

Our findings support the possible beneficial effects of metformin on improving pain, ADL, Sport/Rec, and QOL in OA patients. Our findings support the association between the CC genotype of Bcl-2 and GG+GA genotypes of CXCL-16 and OA.

Neuroregeneration of injured peripheral nerve by fraction B of catfish epidermal secretions through the reversal of the apoptotic pathway and DNA damage

Introduction: Crush injuries occur from acute traumatic nerve compression resulting in different degrees of neural damage leading to permanent functional deficits. Recently, we have shown that administration of Fraction B (FB) derived from catfish epidermal secretions accelerates healing of damaged nerve in a sciatic nerve crush injury, as it ameliorates the neurobehavioral deficits and enhances axonal regeneration, as well as protects spinal neurons and increases astrocytic activity and decreasing GAP-43 expression. The present study aimed to investigate the role of FB treatment on the apoptotic pathway in the neuroregeneration of the sciatic nerve crush injury. Methods: Male Wistar rats were randomly assigned into five groups: (I) SHAM, (II) CRUSH, (III) CRUSH + (1.5 mg/kg) FB, (IV) CRUSH + (3 mg/kg) FB, and (V) CRUSH + (4.5 mg/kg) FB. Rats underwent sciatic nerve crush surgery, followed by treatment with FB administered intraperitoneally (IP) daily for two weeks and then sacrificed at the end of the fourth week. Results: FB improved the recovery of neurobehavioral functions with a concomitant increase in axonal regeneration and neuroprotective effects on spinal cord neurons following crush injury. Further, FB enhanced Schwann cells (SCs) proliferation with a significant increase in myelin basic protein expression. FB-treated animals demonstrated higher numbers of neurons in the spinal cord, possibly through ameliorating oxidative DNA damage and alleviating the mitochondrial-dependent apoptotic pathway by inhibiting the release of cytochrome c and the activation of caspase-3 in the spinal cord neurons. Conclusion: FB alleviates the neurodegenerative changes in the lumbar spinal cord neurons and recovers the decrease in the neuronal count through its anti-apoptotic and DNA antioxidative properties.

Evaluation of Bcl-2 as a marker for chronic kidney disease prediction in cats

Chronic kidney disease (CKD) is a frequent condition in elderly cats. Bcl-2 is linked to kidney disease through the processes of apoptosis and fibrosis. The purpose of this study is to examine Bcl-2 levels in CKD and clinically healthy age-matched cats in order to evaluate the relationship between Bcl-2 levels, signalment, and blood parameters in cats with CKD. The circulating levels of Bcl-2 were determined using an immunoassay in twenty-four CKD cats and eleven clinically healthy age-matched cats by the utilization of the general linear model (GLM), Pearson correlation, principal component analysis (PCA), ROC curves, the Cox hazard model, and Kaplan-Meier survival analysis. These were all conducted in order to explore Bcl-2 levels and their connection with other variables. The Bcl-2 immunohistochemical intensity was graded in each glomerulus and tubulointerstitium. McNemar's test was performed in order to compare the expression of Bcl-2 in the two renal tissue sites. The circulating Bcl-2 of CKD cats was significantly lower than those of clinically healthy age-matched cats (P = 0.034). The presence of circulating Bcl-2 (P < 0.01) and the severity of CKD (P = 0.02) were both linked with the survival time of cats with CKD. The area under the curve (AUC) of Bcl-2 for detection of CKD was 0.723. In cats, decreased circulating Bcl-2 was associated with increased blood BUN, creatinine levels, and CKD severity. Bcl-2 protein expression was reduced in the renal tissues of CKD cats as the disease progressed, resulting in a decrease in their survival time. This study demonstrated that Bcl-2 may be effective in diagnosing feline CKD.

Vitamin D ameliorates diethylnitrosamine-induced liver preneoplasia: A pivotal role of CYP3A4/CYP2E1 via DPP-4 enzyme inhibition

Growing evidence has indicated that vitamin D (Vit D) regulates cell proliferation and differentiation in cancer cells. Accordingly, the present study was conducted to investigate the possible beneficial effects of Vit D on diethylnitrosamine (DEN)-induced liver preneoplasia. The effect of Vit D on HepG2 cells was investigated using MTT assay. Additionally, liver preneoplasia was induced in Swiss male albino mice by giving overnight fasted animals 5 consecutive doses of DEN (75 mg/kg/week). Oral treatment with Vit D (200 IU/kg/day) was initiated either 2 weeks before DEN (first protocol) or 1 week after the first dose of DEN injection (second protocol). At the end of the experiment, tissue levels of GGT, DPP-4, TNF-α, IL-6, CYP2E1, and CYP3A4 were also estimated. Moreover, the histopathological study of liver tissue and immunohistochemical detection of GST-P, PCNA, and NF-κB were performed. Vit D exerted a significant cytotoxic effect on HepG2 cells via significantly increasing BAX, p53, and BAX/Bcl2 ratio, and significantly decreasing Bcl2 mRNA expression. In both in vivo protocols, Vit D was capable of normalizing relative liver weight, PCNA, altered hepatocellular foci, and ductular proliferation. Moreover, Vit D significantly reduced the DEN-induced elevation of AST, ALT, ALP, GGT, DDP-4, TNF-α, IL-6, CYP2E1, liver DNA damage, GST-P, NF-κB, nuclear hyperchromasia/pleomorphism, cholestasis, and inflammatory cell aggregates, but significantly increased CYP3A4 content. In conculsion, current results reflect the potential impact of Vit D in the management of early stages of liver cancer.

Endoplasmic Reticulum Stress and Impairment of Ribosome Biogenesis Mediate the Apoptosis Induced by Ocimum x africanum Essential Oil in a Human Gastric Cancer Cell Line

Background and Objectives: Gastric cancer remains a major unmet clinical problem worldwide. Although conventional medical treatments are available, their curative effects are generally unsatisfactory. Consequently, it remains necessary to search natural products for potential alternatives in treating gastric cancer patients. Ocimum x africanum Lour. is a culinary herb that has been used in folk medicine for various diseases, but little is known regarding its anti-cancer activity against gastric cancer cells. In the current study, we focus on the anti-cancer mechanisms of O. x africanum essential oil (OAEO) in the AGS human gastric cancer cell line. Materials and Methods: After OAEO treatment, AGS cell viability was evaluated by MTT assay. Cell migration and apoptotic nuclear morphology were determined by wound-healing assay and DAPI staining, respectively. Gene expression levels of apoptosis-related genes were quantified by qRT–PCR. Differential protein expression was determined with an LC–MS/MS-based proteomics approach to identify the key proteins that may be important in the anti-cancer mechanisms of OAEO on AGS cells. The chemical constituents of OAEO were identified by GC–MS analysis. Results: We found OAEO to exhibit a potent growth-inhibiting effect on AGS cells, with an IC₅₀ value of 42.73 µg/mL. After OAEO treatment for 24 h, AGS cell migration was significantly decreased relative to the untreated control. OAEO-treated AGS cells exhibited common features of apoptotic cell death, including cell shrinkage, membrane blebbing, chromatin condensation, and nuclear fragmentation. Apoptotic cell death was confirmed by qRT–PCR for apoptosis-related genes, revealing that OAEO decreased the expression of anti-apoptotic genes (BCL2 and BCL-xL) and activated pro-apoptotic genes and apoptotic caspase genes (TP53, BAX, CASP9, CASP12, and CASP3). Moreover, expression of CASP8 was not changed after treatment. Proteomic analysis revealed that OAEO may produce a signature effect on protein clusters relating to unfolded protein accumulation, thereby inducing severe ER stress and also impairing ribosome synthesis. STRING analysis revealed seven up-regulated and 11 down-regulated proteins, which were significantly associated with protein folding and ribosome biogenesis, respectively. Using GC–MS analysis, 6-methyl-5-hepten-2-one, citral, neral, and linalool were found to be the major chemical constituents in OAEO. Conclusions: Taken together, these results indicate that OAEO has a potential anti-proliferative effect on AGS cells. Our molecular findings show evidence supporting an important role of ER stress and ribosome biogenesis impairment in mediating the induction of cell death by OAEO through the mitochondrial-apoptotic pathway. This study, therefore, provides fundamental knowledge for future applications using OAEO as an alternative therapy in gastric cancer management.

Characterization of the Secretome of a Specific Cell Expressing Mutant Methionyl-tRNA Synthetase in Co-Culture Using Click Chemistry

Co-culture system, in which two or more distinct cell types are cultured together, is advantageous in that it can mimic the environment of the in vivo niche of the cells. In this study, we presented a strategy to analyze the secretome of a specific cell type under the co-culture condition in serum-supplemented media. For the cell-specific secretome analysis, we expressed the mouse mutant methionyl-tRNA synthetase for the incorporation of the non-canonical amino acid, azidonorleucine into the newly synthesized proteins in cells of which the secretome is targeted. The azidonorleucine-tagged secretome could be enriched, based on click chemistry, and distinguished from any other contaminating proteins, either from the cell culture media or the other cells co-cultured with the cells of interest. In order to have more reliable true-positive identifications of cell-specific secretory bodies, we established criteria to exclude any identified human peptide matched to bovine proteins. As a result, we identified a maximum of 719 secreted proteins in the secretome analysis under this co-culture condition. Last, we applied this platform to profile the secretome of mesenchymal stem cells and predicted its therapeutic potential on osteoarthritis based on secretome analysis.

Dysregulation of Transcription Profile of Selenoprotein in Patients with Kashin-Beck Disease and Its Effect on Se Deficiency-Induced Chondrocyte Apoptosis

Kashin-Beck disease (KBD) is a chronic, degenerative osteoarthropathy related to selenium (Se) deficiency. Se participates in the synthesis of selenoprotein in the form of selenocysteine. In total, 25 selenoproteins, encoded by 25 genes, are currently found in humans; however, the effects of selenoprotein genes on chondrocyte apoptosis, particularly in apoptosis-related genes, remain poorly elucidated. Therefore, in the current study, the expression of selenoprotein genes and apoptosis-related genes were determined by RT-qPCR in patients and chondrocytes and the correlations between them were analyzed using Pearson and Spearman's rank correlation, and the chondrocyte apoptosis rate was detected by Annexin V-FITC/PI. The results showed that the mRNA levels of 17 selenoprotein genes were downregulated, whereas two genes were upregulated in patients with KBD. The BAX/BCL2 ratio and the mRNA levels of BAX and P53 were increased, but the mRNA levels of BCL2 and NF-κB p65 were decreased in patients with KBD. The mRNA levels of GPX2, GPX3, DIO1, TXNRD1, TXNRD3, and SPS2 were most closely associated with apoptosis-related genes in patients with KBD. Moreover, in the Se deficiency group, the mRNA levels of GPX3, DIO1, and TXNRD1 were downregulated and GPX activity was decreased, but the late apoptosis rate, the mRNA levels of BAX and P53, and the BAX/BCL2 ratio were increased; the opposite trend was observed in the Se supplement group. Collectively, these results indicate that selenoprotein transcription profile is dysregulated in patients with KBD. Furthermore, the expression of GPX3, DIO1, and TXNRD1 genes might be involved in the development of chondrocyte apoptosis by affecting antioxidant capacity.

Sprifermin: Effects on Cartilage Homeostasis and Therapeutic Prospects in Cartilage-Related Diseases

When suffering from osteoarthritis (OA), articular cartilage homeostasis is out of balance and the living quality declines. The treatment of knee OA has always been an unsolved problem in the world. At present, symptomatic treatment is mainly adopted for OA. Drug therapy is mainly used to relieve pain symptoms, but often accompanied with adverse reactions; surgical treatment involves the problem of poor integration between the repaired or transplanted tissues and the natural cartilage, leading to the failure of repair. Biotherapy which aims to promote cartilage in situ regeneration and to restore endochondral homeostasis is expected to be an effective method for the prevention and treatment of OA. Disease-modifying osteoarthritis drugs (DMOADs) are intended for targeted treatment of OA. The DMOADs prevent excessive destruction of articular cartilage through anti-catabolism and stimulate tissue regeneration via excitoanabolic effects. Sprifermin (recombinant human FGF18, rhFGF18) is an effective DMOAD, which can not only promote the proliferation of articular chondrocyte and the synthesis of extracellular matrix, increase the thickness of cartilage in a dose-dependent manner, but also inhibit the activity of proteolytic enzymes and remarkedly slow down the degeneration of cartilage. This paper reviews the unique advantages of Sprifermin in repairing cartilage injury and improving cartilage homeostasis, aiming to provide an important strategy for the effective prevention and treatment of cartilage injury-related diseases.

Mesenchymal Stem Cell-Derived Extracellular Vesicles for Osteoarthritis Treatment: Extracellular Matrix Protection, Chondrocyte and Osteocyte Physiology, Pain and Inflammation Management

Osteoarthritis (OA) is a common degenerative disease that can lead to persistent pain and motion restriction. In the last decade, stem cells, particularly mesenchymal stem cells (MSCs), have been explored as a potential alternative OA therapy due to their regenerative capacity. Furthermore, it has been shown that trophic factors enveloped in extracellular vesicles (EVs), including exosomes, are a crucial aspect of MSC-based treatment for OA. Evidently, EVs derived from different MSC sources might rescue the OA phenotype by targeting many biological processes associated with cartilage extracellular matrix (ECM) degradation and exerting protective effects on different joint cell types. Despite this advancement, different studies employing EV treatment for OA have revealed reverse outcomes depending on the EV cargo, cell source, and pathological condition. Hence, in this review, we aim to summarize and discuss the possible effects of MSC-derived EVs based on recent findings at different stages of OA development, including effects on cartilage ECM, chondrocyte biology, osteocytes and bone homeostasis, inflammation, and pain management. Additionally, we discuss further strategies and technical advances for manipulating EVs to specifically target OA to bring the therapy closer to clinical use.

Cytotoxic effects of dental calculus particles and freeze-dried Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum on HSC-2 oral epithelial cells and THP-1 macrophages

BACKGROUND

Periodontitis is an inflammatory disease initiated by dental deposits. Microorganisms in the dental biofilm induce cell death in epithelial cells, contributing to the breakdown of epithelial barrier function. Recently, dental calculus has also been implicated in pyroptotic cell death in oral epithelium. We analyzed the cytotoxic effects of dental calculus and freeze-dried periodontopathic bacteria on oral epithelial cells and macrophages.

METHODS

HSC-2 (human oral squamous carcinoma cells) and phorbol 12-myristate 13-acetate-differentiated THP-1 macrophages were exposed to dental calculus or one of two species of freeze-dried bacterium, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum. Following incubation for 24 hours, we measured cytotoxicity via lactate dehydrogenase release. Cells were then incubated with glyburide, an NLRP3 inflammasome inhibitor, to assess the potential role of pyroptosis. We also conducted a permeability assay to analyze the effects on epithelial barrier function.

RESULTS

Dental calculus induced dose-dependent cell death in HSC-2 cells, whereas cell death induced by freeze-dried bacteria was insignificant. Conversely, freeze-dried bacteria induced more cell death than dental calculus in THP-1 macrophages. Cell death induced by dental calculus but not by freeze-dried bacteria was inhibited by glyburide, indicating that these are different types of cell death. In the permeability assays, dental calculus but not freeze-dried bacteria attenuated the barrier function of HSC-2 cell monolayers.

CONCLUSION

Due to the low sensitivity of HSC-2 cells to microbial cytotoxicity, dental calculus had stronger cytotoxic effects on HSC-2 cell monolayers than freeze-dried A. actinomycetemcomitans and F. nucleatum, suggesting that it plays a critical role in the breakdown of crevicular/pocket epithelium integrity.

An In Vitro Anti-Cancer Activity of Ocimum tenuiflorum Essential Oil by Inducing Apoptosis in Human Gastric Cancer Cell Line

Background and Objectives: The effects of Ocimum tenuiflorum essential oil (OTEO) against gastric cancer remain unknown and merit investigation. Materials and Methods: In the present study, the anti-cancer activity of OTEO was examined in a human gastric cancer cell line (AGS). After OTEO treatment, AGS cell viability was determined by an MTT assay, and inhibition of metastasis was determined by cell migration and invasion assays. The expression of apoptosis-related genes in treated AGS cells was determined by qRT-PCR. Results: OTEO significantly decreased AGS cell viability in a dose-dependent manner (IC₅₀ 163.42 µg/mL) and effectively inhibited cell migration and invasion. Morphological examination demonstrated that OTEO induced cell shrinkage, chromatin condensation, and fragmentation, which are considered typical morphologies of apoptotic cell death. Pro-apoptotic genes (TP53, BAX, and BAK) were significantly up-regulated, while anti-apoptotic genes (BCL-2 and BCL-xL) were significantly down-regulated after treatment with OTEO. In addition, significantly increased gene expression was detected for CASP8, CASP9, and CASP3 in AGS cells exposed to OTEO. GC-MS analysis demonstrated that the major compound of OTEO was caryophyllene (25.85%) and α-pinene (11.66%). Conclusions: This in vitro study demonstrates for the first time that OTEO has potential anti-gastric cancer activity and may induce apoptosis in AGS cells through extrinsic and intrinsic pathways.

Scorpion Venom Peptide Effects on Inhibiting Proliferation and Inducing Apoptosis in Canine Mammary Gland Tumor Cell Lines

The most common neoplasms in intact female dogs are CMGTs. BmKn-2, an antimicrobial peptide, is derived from scorpion venom and has published anticancer effects in oral and colon human cancer cell lines. Thus, it is highly likely that BmKn-2 could inhibit CMGT cell lines which has not been previously reported. This study investigated the proliferation and apoptotic properties of BmKn-2 via Bax and Bcl-2 relative gene expression in two CMGT cell lines, metastatic (CHMp-5b) and non-metastatic (CHMp-13a). The results showed that BmKn-2 inhibited proliferation and induced apoptosis in the CMGT cell lines. The cell morphology clearly changed and increased apoptosis in a dose dependent of manner. The half maximum inhibitory concentration (IC₅₀) was 30 µg/mL for CHMp-5b cell line and 54 µg/mL for CHMp-13a cell line. The induction of apoptosis was mediated through Bcl-2 and Bax expression after BmKn-2 treatment. In conclusion, BmKn-2 inhibited proliferation and induced apoptosis in both CHMp-5b and CHMp-13a cell lines via down-regulation of Bcl-2 and up-regulation of Bax relative mRNA expression. Therefore, BmKn-2 could be feasible as candidate treatment for CMGTs.

HDAC2 interacts with microRNA-503-5p to regulate SGK1 in osteoarthritis

Background

Osteoarthritis (OA) is a disabling joint disease that causes articular cartilage degeneration. It has been implicated that altered expression of histone deacetylase 2 (HDAC2) is found in patients with OA. However, the specific role of HDAC2 in the development of OA still remains enigmatic. Hence, we sought to characterize the functional relevance of HDAC2 in the development of OA.

Methods

Anterior cruciate ligament surgery was performed to generate the rat model of OA. Luciferase assay was performed to evaluate the relationship between microRNA-503-5p (miR-503-5p) and serum- and glucocorticoid-inducible kinase-1 (SGK1). Functional experiments were conducted to examine the functional significance of miR-503-5p, histone deacetylase 2 (HDAC2), and SGK1 on the progression of OA by determining proliferation, apoptosis, and expression of apoptosis-associated proteins and inflammatory cytokines.

Results

HDAC2 could inhibit miR-503-5p expression. SGK1 was the target gene of miR-503-5p. Upregulation of miR-503-5p or silencing of HDAC2 contributed to enhanced proliferation, suppressed apoptosis (reduced expression of Caspase-3 and Bax but elevated expression of Bcl2), and promoted inflammation in chondrocytes of OA rats.

Conclusion

In conclusion, our study demonstrated that HDAC2 could promote OA through miR-503-5p/SGK1 axis, which might function as a therapeutic target for OA treatment.

Effects of the secretome of human Wharton's jelly mesenchymal stem cells on the proliferation and apoptosis gene expression of the retinal pigmented epithelium

Human retinal pigmented epithelium (RPE) can undergo an uncontrolled proliferation in some disorders such as retinal detachment associated with proliferative vitreoretinopathy (PVR). The present study was conducted to evaluate the effect of the conditioned medium secreted by human Wharton's jelly mesenchymal stem cells (WJMSCs-CM) on the proliferation and apoptosis gene expression of the RPE. WJMSCs-CM was collected from WJMSCs after two periods of 24-h and 9-h culture in serum-free medium. RPE cells were cultured in WJMSCs-CM versus serum-deprived media for 24 h. The effect of WJMSCs-CM on RPE cell proliferation was determined using the MTT assay. Relative expression of apoptotic genes (Bcl2, Bax, and IL-1B) was also assessed by real-time PCR. MTT assay demonstrated that RPE cell viability was reduced significantly in WJMSCs-CM treated RPE cells compared to those cultured in serum-deprived medium (64.23 ± 2.44 vs 100.10 ± 5.68; P = 0.006). Moreover, the expression of anti-apoptotic Bcl2 was significantly decreased in WJMSCs-CM compared to serum-deprived medium (0.52 ± 0.06 in WJMSCs-CM vs 1.02 ± 0.2 in serum-free treatment; P = 0.03), while the expression of pro-apoptotic biomarkers of Bax and IL-1B was not significantly different between the two treatments. The represented data showed that WJMSCs-CM can induce apoptosis in RPE cells in vitro through activating apoptosis pathways. This proof-of-the-concept study provides basic evidence for the possible effect of WJMSCs-CM on preventing PVR.

MiRNA 34-a regulate SIRT-1 and Foxo-1 expression in endometriosis

PURPOSE

The role of the Sirutin 1 (SIRT1) and MicroRNA-34 a (miR-34a) in endometriosis and the extent to which the miR-34a/SIRT1/p53 signaling pathway is involved in its pathogenesis is unclear, so we aimed to investigate the expression of miRNA 34-a, SIRT1, Forkhead boxO (FoxO-1), p53 and other apoptotic markers in endometrial tissue of women with endometriosis in order to better understand their role and the mechanisms of their actions in the pathogenesis of such disease and if it is related to apoptosis or not.

METHODS

Ectopic and eutopic endometriotic tissues were collected from seventy women with endometriosis while normal endometrial tissues were obtained from 40 fertile women without endometriosis and then gene expression of SIRT-1, miR-34a,p53, Bax, Bcl-2, Bcl-xL and FoxO-1 were measured using RT-PCR.

RESULTS

We detected that SIRT-1 and Bcl-xL genes expressions was significantly up-regulated while miRNA34-a,p53, Bax, Bcl-2 and FoxO-1 were down-regulated in endometrial tissue of endometriotic patients compared to that of those without endometriosis. There was an inverse relationship between SIRT-1a, Bcl-xL genes expressions and miR-34a, p53, Bax, Bcl-2 expressions as well as FoxO-1 expression. These results imply that miR-34a might regulate p53 through SIRT-1 and subsequently FoxO-1 expression in endometriotic tissue, and so it can contribute to the pathogenesis of endometriosis by decreasing the naturally occurring apoptosis in endometrium.

CONCLUSION

This study may provide a potential biomarker for endometriosis therapeutics. Identification of target genes downstream of these transcriptional factors would allow better understanding of their respective roles in the pathogenesis of endometriosis.

Oxidative Stress Induces Chondrocyte Apoptosis through Caspase-Dependent and Caspase-Independent Mitochondrial Pathways and the Antioxidant Mechanism of Angelica Sinensis Polysaccharide

Introduction

Chondrocyte apoptosis is considered one of the pathogenic factors of osteoarthritis (OA), but its importance in the pathogenesis of OA remains unclear. Recent research adds progress to the knowledge that the mitochondrial signaling pathway mediates chondrocyte apoptosis in OA.

Method

Rat chondrocyte exposed to H₂O₂ was used as the experimental oxidative stress model. Chondrocyte viability was tested by cell counting kit-8 (CCK-8) assay. Cell apoptosis and ROS were tested by flow cytometry. Contents of malondialdehyde (MDA), catalase (CAT), caspase-3, caspase-9, cytochrome C, superoxide dismutase (SOD)-2, and adenosine triphosphate (ATP) were evaluated by biochemical detection. The expressions of related genes and proteins were assessed by quantitative polymerase chain reaction (qPCR) and western blot.

Results

H₂O₂ provokes oxidative stress and decreases the viability of chondrocyte, which leads to the release of cytochrome C and inhibition of SOD-2 activity. The damage of mitochondrion disturbs the energy metabolism of chondrocyte and eventually induces chondrocyte apoptosis through the mitochondrial pathway. Furthermore, pretreated with anglicasinensis polysaccharide (ASP) or caspase inhibitors increase the expression of Bcl-2 and Bcl-xL but do not work for the expression of Bax and Bad.

Conclusion

Oxidative stress induces chondrocyte apoptosis through caspase-dependent and caspase-independent mitochondrial pathways. ASP protects chondrocyte from H₂O₂-induced oxidative stress and subsequent cell injury through its antioxidant effect by inhibiting the caspase pathway.

LncRNA NEAT1 regulates chondrocyte proliferation and apoptosis via targeting miR-543/PLA2G4A axis

Osteoarthritis (OA), which is characterized by articular cartilage degeneration, shows a gradually increasing incidence with age. This study explored the molecular mechanism underlying the proliferation and apoptosis of chondrocytes during OA progression. In this study, chondrocytes were isolated from human knee cartilages. The targeted relationship among nuclear enriched abundant transcript 1 (NEAT1), microRNA-543 (miR-543) and PLA2G4A was predicted on TargetScan V7.2 and starBase and validated by performing dual-luciferase reporter assay. High-expressed NEAT1 was detected in OA cartilage and chondrocytes. NEAT1 was negatively correlated with miR-543 and was low-expressed in OA cartilage and PLA2G4A was negatively correlated with miR-543 and was high-expressed in OA cartilage. In OA chondrocytes, the overexpressed NEAT1 inhibited the expressions of p-Akt1 and Bcl-2 and upregulated that of matrix metalloprotease (MMP)-3, MMP-9, MMP-13, interleukin (IL)-6 and IL-8, but such effects of overexpressed NEAT1 were reversed by miR-543 mimic. SiRNA-NEAT1 exerted an opposite effect to NEAT1 overexpression on OA chondrocytes, but this could be reversed by miR-543 inhibitor. The effect of PLA2G4A overexpression was the opposite to miR-543 mimic on OA chondrocytes. In conclusion, NEAT1 could sponge miR-543 to induce PLA2G4A expression, inhibit chondrocyte proliferation and promote apoptosis.

Antiviral Activity of Chitosan Nanoparticles Encapsulating Curcumin Against Hepatitis C Virus Genotype 4a in Human Hepatoma Cell Lines

Purpose

Current direct-acting antiviral agents for treatment of hepatitis C virus genotype 4a (HCV-4a) have been reported to cause adverse effects, and therefore less toxic antivirals are needed. This study investigated the role of curcumin chitosan (CuCs) nanocomposite as a potential anti-HCV-4a agent in human hepatoma cells Huh7.

Methods

Docking of curcumin and CuCs nanocomposite and binding energy calculations were carried out. Chitosan nanoparticles (CsNPs) and CuCs nanocomposite were prepared with an ionic gelation method and characterized with TEM, zeta size and potential, and HPLC to calculate encapsulation efficiency. Cytotoxicity studies were performed on Huh7 cells using MTT assay and confirmed with cellular and molecular assays. Anti-HCV-4a activity was determined using real-time PCR and Western blot.

Results

The strength of binding interactions between protein ligand complexes gave scores with NS3 protease, NS5A polymerase, and NS5B polymerase of -124.91, -159.02, and -129.16, for curcumin respectively, and -68.51, -54.52, and -157.63 for CuCs nanocomposite, respectively. CuCs nanocomposite was prepared at sizes 29-39.5 nm and charges of 33 mV. HPLC detected 4% of curcumin encapsulated into CsNPs. IC50 was 8 µg/mL for curcumin and 25 µg/mL for the nanocomposite on Huh7 but was 25.8 µg/mL and 34 µg/mL on WISH cells. CsNPs had no cytotoxic effect on tested cell lines. Apoptotic genes' expression revealed the caspase-dependent pathway mechanism. CsNPs and CuCs nanocomposite demonstrated 100% inhibition of viral entry and replication, which was confirmed with HCV core protein expression.

Conclusion

CuCs nanocomposite inhibited HCV-4a entry and replication compared to curcumin alone, suggesting its potential role as an effective therapeutic agent.

MiR-375 Mediates Chondrocyte Metabolism and Oxidative Stress in Osteoarthritis Mouse Models through the JAK2/STAT3 Signaling Pathway

OBJECTIVE

The aim of this work was to determine the effect of miR-375 on chondrocyte metabolism and oxidative stress in osteoarthritis (OA) mouse models through the JAK2/STAT3 signaling pathway.

METHODS

Chondrocytes were divided into control, IL-1β, IL-1β + miR-375 mimic, IL-1β + miR-375 inhibitor, IL-1β + miR-NC (negative control), and IL-1β + miR-375 inhibitor + siJAK2 groups. The chondrocyte proliferation was determined by MTT assay, the superoxide dismutase (SOD) and malondialdehyde (MDA) levels by corresponding kits, and the chondrocyte apoptosis by TUNEL staining. Furthermore, OA mouse models were divided into Sham, OA + miR-NC, and OA + miRNA-375 antagomir groups. The pathological changes were observed, and the expressions of miR-375 and the JAK2/STAT3 pathway were determined by qRT-PCR and Western blotting, respectively.

RESULTS

IL-1β-induced chondrocytes had significant increases in miR-375 and MDA, with decreased proliferation and SOD levels, as compared to the control group. Meanwhile, they also exhibited elevated apoptosis, with upregulations of ADAMTS-5 and MMP-13 and downregulations of COL2A1 and ACAN, as well as decreased p-JAK2/JAK2, p-STAT3/STAT3, and Bcl-2/Bax. However, these changes were significantly improved after transfection with miR-375 inhibitor, but transfection with miR-375 mimic resulted in severer exacerbation. Notably, the improvement of miR-375 inhibitor could be abolished by transfection with siJAK2. Furthermore, miR-375 antagomir significantly alleviated OA progression in OA mice in vivo.

CONCLUSION

MiR-375 suppression enhanced the ability of chondrocyte to antagonize the oxidative stress and maintained the homeostasis of extracellular matrix metabolism to protect chondrocytes from OA via activation of the JAK2/STAT3 pathway, indicating that miR-375 is a potential molecular target for OA treatment.

Nesfatin-1 suppresses interleukin-1β-induced inflammation, apoptosis, and cartilage matrix destruction in chondrocytes and ameliorates osteoarthritis in rats

Osteoarthritis (OA) is a chronic degenerative joint disease, related to the overexpression of matrix metalloproteinases (MMPs), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS), inflammation, and chondrocyte apoptosis. Nesfatin-1 is an adipokine, which plays an important role in the development of OA, especially in obese people. In the present study, cartilage degradation and apoptosis observed in OA patients was evaluated. Furthermore, the anti-inflammatory and anti-apoptotic effects of nesfatin-1, and its underlying in vitro and in vivo mechanisms were investigated. The results showed that nesfatin-1 increased significantly the expression of collagen type II alpha 1 chain (Col2a1), and reduced the expression of MMPs, ADAMTS5, cyclooxygenase (COX)-2, caspase-3, nitric oxide (NO), inducible nitric oxide synthase (iNOS), prostaglandin E2 (PGE2), interleukin (IL)-6, and chondrocyte apoptosis rate, which may be induced by IL-1β in rat chondrocytes. Furthermore, nesfatin-1 treatment prevented cartilage degeneration in the rat OA model. It was found that nesfatin-1 suppressed the IL-1β-induced activation of NF-κB, the mitogen-activated protein kinase (MAPK), and the Bax/Bcl-2 signal pathway in chondrocytes. These results suggest that in vivo nesfatin-1 could play a protective role in the development of OA and can be potentially used for its treatment.

RETRACTED: Human bone mesenchymal stem cells-derived exosomes overexpressing microRNA-26a-5p alleviate osteoarthritis via down-regulation of PTGS2

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concern was raised about the reliability of the Western blot results in Figures 2E, 3D and F, 4B, E+G, 5D+I, and 6D+F, which appear to have a similar phenotype as contained in many other publications, detailed here: https://pubpeer.com/publications/73C0A79F5EDF9ECC9818CE2D9B2A09; and here: https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. The provenance of the flow cytometry data in Figure 5A was also questioned, as it appeared to have histograms that were hand drawn. The journal requested the corresponding author comment on these concerns and provide the raw data. The authors did not respond to this request and therefore the Editor-in-Chief decided to retract the article.

Linagliptin protects human chondrogenic ATDC5 cells against advanced glycation end products (AGEs)-induced apoptosis via a mitochondria-dependent pathway

Chondrocytes in joints are responsible for the formation and remodeling of articular cartilage. The accumulation of advanced glycation end products (AGEs) in cartilage is detrimental to the survival of chondrocytes. Linagliptin is one of the most commonly used anti-diabetes agents, and recent work indicates that it exerts an anti-inflammatory effect in different cell types. In this study, we showed that Linagliptin had a protective role in AGEs-induced chondrocyte injury. The presence of Linagliptin ameliorated AGEs-induced reactive oxygen species (ROS) induction and reduced cellular protein carboxyl content. Linagliptin mitigated AGEs-induced mitochondrial membrane potential (_ΔΨm) reduction and NAPDH oxidase subunit NOX-4 induction, indicating that Linagliptin is a potent anti-ROS agent in chondrocytes. Additionally, Linagliptin inhibited AGEs-induced production of high mobility group box chromosomal protein 1 (HMGB-1), and the expression of matrix metalloproteases (MMPs)-2 and -9. Flow cytometry experimentation showed that Linagliptin inhibited AGEs-induced apoptotic subpopulation. Moreover, Linagliptin inhibited the AGEs-induced increased ratio of Bax to Bcl-2, translocation of cytochrome C from mitochondria to the cytoplasm, and release of cleaved caspase-3. Collectively, our data indicate that the anti-diabetes drug Linagliptin has a new role in rescuing chondrocyte from insult by AGEs, and may, therefore, have the potential to treat joint disorders.

Astaxanthin induces apoptosis and increases activity of antioxidant enzymes in LS-180 cells

Astaxanthin, a Xanthophyll carotenoid, has strong antioxidant properties. Some studies have shown the effectiveness of this compound on the prevention and treatment of cancer. Therefore, the aim of this study was to evaluate the effects of astaxanthin on induction of apoptosis and antioxidant activity in the LS-180 cell line. In this experimental study, after the treatment of LS-180 50, 100 and 150 μm of Astaxanthin for 24 h, the expression levels of Bax, Bcl2 and Caspase3 genes were investigated by Real-time PCR. Also, the level of malondialdehyde, as an indicator of oxidative stress and activity of anti-superoxide dismutase enzymes, catalase and glutathione peroxidase was investigated by colorimetric methods. The results showed that astaxanthin increases the expression of Bax and Caspase3 genes and decreases that of Bcl2, thereby, inducing apoptosis and inhibiting growth and proliferation of the cells. Additionally, reduction in the levels of malondialdehyde was evident with a significant elevation in antioxidant activity mediated by the action of superoxide dismutase, catalase and glutathione peroxidase. These results suggest that astaxanthin has the potency to induce apoptosis in LS-180 cells by increasing the expression of apoptotic genes and activity of antioxidant enzymes. Thus, astaxanthin has potential in the prevention and treatment of cancer.

Ablation of low-molecular-weight FGF2 isoform accelerates murine osteoarthritis while loss of high-molecular-weight FGF2 isoforms offers protection

FGF2 is an essential growth factor implicated in osteoarthritis (OA), and deletion of full-length FGF2 (Fgf2ALLKO ) leads to murine OA. However, the FGF2 gene encodes both high-molecular-weight (HMW) and low-molecular-weight (LMW) isoforms, and the effects of selectively ablating individual isoforms, as opposed to total FGF2, has not been investigated in the context of OA. We undertook this study to examine whether mice lacking HMW FGF2 (Fgf2HMWKO ) or LMW FGF2 (Fgf2LMWKO ) develop OA and to further characterize the observed OA phenotype in Fgf2ALLKO mice. Fgf2HMWKO mice never developed OA, but 6- and 9-month-old Fgf2LMWKO and Fgf2ALLKO mice displayed signs of OA, including eroded articular cartilage, altered subchondral bone and trabecular architecture, and increased OA marker enzyme levels. Even with mechanical induction of OA, Fgf2HMWKO mice were protected against OA, whereas Fgf2LMWKO and Fgf2ALLKO displayed OA-like changes of the subchondral bone. Before exhibiting OA symptoms, Fgf2LMWKO or Fgf2ALLKO joints displayed differential expression of genes encoding key regulatory proteins, including interleukin-1β, insulin-like growth factor 1, bone morphogenetic protein 4, hypoxia-inducible factor 1, B-cell lymphoma 2, Bcl2-associated X protein, a disintegrin and metalloproteinase with thrombospondin motifs 5, ETS domain-containing protein, and sex-determining region Y box 9. Moreover, Fgf2LMWKO OA cartilage exhibited increased FGF2, FGF23, and FGFR1 expression, whereas Fgf2HMWKO cartilage had increased levels of FGFR3, which promotes anabolism in cartilage. These results demonstrate that loss of LMW FGF2 results in catabolic activity in joint cartilage, whereas absence of HMW FGF2 with only the presence of LMW FGF2 offers protection from OA.

Bax Targeted by miR-29a Regulates Chondrocyte Apoptosis in Osteoarthritis

Osteoarthritis (OA) is a chronic degenerative joint disease, where chondrocyte apoptosis is responsible for cartilage degeneration. Bax is a well-known proapoptotic protein of the Bcl-2 family, involved in a large number of physiological and pathological processes. However, the regulation mechanisms of Bax underlying chondrocyte apoptosis in OA remain unknown. In the present study, we determined the role of Bax in human OA and chondrocyte apoptosis. The results showed that Bax was upregulated in chondrocytes from the articular cartilage of OA patients and in cultured chondrocyte-like ATDC5 cells treated by IL-1β. Bax was identified to be the direct target of miR-29a by luciferase reporter assay and by western blotting. Inhibition of miR-29a by the mimics protested and overexpression by miR-29a inhibitors aggravated ATDC5 apoptosis induced by IL-1β. These data reveal that miR-29a/Bax axis plays an important role in regulating chondrocyte apoptosis and suggest that targeting the proapoptotic protein Bax and increasing expression levels of miR-29a emerge as potential approach for protection against the development of OA.

The effects of particle density in moxa smoke on the ultrastructure of knee cartilage and expressions of TNF-α, IL-1b, BAX, and Bcl-2 mRNA in a rat model for osteoarthritis

BACKGROUND

The effectiveness of smokeless moxa and other means to reduce exposure are extensively investigated with regards to the health consequences of inhalation of moxa smoke, and clinical studies indicate that classical moxibustion is superior to smokeless moxa. This study aims to quantify the effects of particle density in moxa smoke on the clinical outcome with an established model, demonstrated to be effective for classical moxibustion.

OBJECTIVES

The purpose of this study is to explore the effects of particle density in moxa smoke on the ultrastructure of knee cartilage and expression of cytokine, tissue necrosing factor-alpha (TNF-α), interleukin 1 beta (IL-1b), apoptosis regulator, B-cell lymphoma-2 (Bcl-2), and BAX in a rat model for inflammatory joint disease.

METHODS

Fifty healthy experimental rats were randomly divided into five groups, including normal control, model control, and moxa exposure groups with low, medium, and high particle density, and n = 10/group. In addition, a knee osteoarthritis model was duplicated in the model control and moxa exposure groups. Finally, the ultrastructure of knee cartilage was observed using transmission electron microscopy, and messenger RNA (mRNA) expressions of TNF-α, IL-1b, BAX, and Bcl-2 were determined with quantitative fluorescence methodology.

RESULTS

In the model control and moxa exposure groups, knee cartilage indicated that histologic changes with the degree of injury were inversely proportional to moxa smoke density. The mRNA expressions of TNF-α, IL-1b, and BAX in synovial fluid, as an acute phase reactant, were similarly inversely related to moxa smoke density, but significantly increased. In contrast, Bcl-2, as an antiapoptotic, was substantially decreased in the model, while its levels were directly proportional to moxa smoke density. Besides, the ratio of Bcl-2/BAX mRNA was sharply decreased in the model group, but with levels proportional to moxa smoke density.

CONCLUSIONS

A correlation was found between the particle density in moxa smoke and degree of injury to knee cartilage, favoring higher particle densities. This can be partially related to the suppression of the inflammatory effects of TNF-α, IL-1b, enhancement of the antiapoptotic effects of Bcl-2, and, nevertheless, suppression of the apoptotic effects of BAX. Finally, the protective effect of antiapoptotic is one of the key mechanisms for an ambient moxa smoking environment.

Quantitative analysis and study of the mRNA expression levels of apoptotic genes BCL2, BAX and BCL2L12 in the articular cartilage of an animal model of osteoarthritis

Background

Given that apoptosis of chondrocytes is one of the most important factors related to the pathogenesis of osteoarthritis (OA), the recent research interest adds progress not only to the knowledge of the molecular signals that mediate apoptosis but also to find new therapeutic targets. This study attempts to investigate the differential expression of BCL2 family genes in the articular cartilage of an experimental animal model of OA.

Methods

In total, 26 New Zealand white rabbits underwent an anterior cruciate ligament transaction, 26 more were subjected to a placebo surgery and 18 specimens constituted the control non-operated group. Thirteen weeks later, samples of cartilage from the osteoarthritic and non-osteoarthritic knees were collected and subjected to analysis of the BCL2, BAX and BCL2L12 gene expression at the mRNA level.

Results

Installed osteoarthritic alterations of varied intensity and of grade 1 up to grade 5, were confirmed according to the OARSI system. Contrary to the physiologically healthy samples, in the osteoarthritic samples the mRNA expression levels of BAX and BCL2L12 genes were found significantly upregulated by signals which can activate apoptosis. However, the difference between BCL2 mRNA expression levels in healthy and osteoarthritic samples was not supported statistically.

Conclusions

Since apoptosis is the main feature of the cartilage degeneration in OA, the effective inhibition of apoptosis of chondrocytes can provide novel and interesting therapeutic strategies for the treatment of OA. Therefore, BAX and BCL2L12 are highlighted as potential therapeutic targets in OA.

Role of long noncoding RNA ZFAS1 in proliferation, apoptosis and migration of chondrocytes in osteoarthritis

OBJECTIVE

This study aimed to investigate the role of long noncoding RNA (lncRNA) ZFAS1 in the development of osteoarthritis (OA) as well as to explore the potential molecular mechanisms.

MATERIAL AND METHODS

The expression of lncRNA ZFAS1 in OA chondrocytes was determined. After cell transfection, the effects of ZFAS1 overexpression on the viability, proliferation, apoptosis and migration of OA chondrocytes were detected. Additionally, the expression levels of Bcl-2, Bax, Caspase-3, and matrix metalloproteinases (MMP1 and MMP13) were determined. The expressions of Wnt3a signaling proteins, and the relationship between ZFAS1 and Wnt3a were detected as well.

RESULTS

The expression of ZFAS1 was down-regulated in OA chondrocytes compared with normal chondrocytes. Overexpression of ZFAS1 promoted the viability, proliferation and migration, and inhibited apoptosis and matrix synthesis of OA chondrocytes. Additionally, overexpressed ZFAS1 significantly decreased Wnt3a factors. The effects of ZFAS1 on OA chondrocytes were achieved by regulating Wnt3a signaling.

CONCLUSIONS

Our study demonstrates that ZFAS1 may promote chondrocyte proliferation, and migration, and decrease apoptosis and matrix synthesis in OA possible via targeting Wnt3a signaling. ZFAS1 provides a potential therapeutic target for OA treatment.

Paeoniflorin inhibits IL-1β-induced chondrocyte apoptosis by regulating the Bax/Bcl-2/caspase-3 signaling pathway

Apoptosis serves a pivotal role in the pathogenesis of osteoarthritis (OA). Increasing evidence has demonstrated that paeoniflorin exerts key properties (including anticancer, anti-inflammation and neuroprotective) for clinical applications. However, the precise role of paeoniflorin in articular cartilage apoptosis remains unknown. The present study explored the effects and potential molecular mechanism of paeoniflorin on rat chondrocyte apoptosis. Rat articular chondrocytes were cultured in monolayers. The lactate dehydrogenase (LDH) release rate of cells was determined by an LDH release assay. Annexin V-fluorescein isothiocyanate and propidium iodide staining were performed to detect early and advanced apoptotic cells by flow cytometry. The activity of caspase-3 in chondrocytes was determined using a caspase-3 activity assay. The expression of B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein (Bax) was examined by reverse transcription‑quantitative polymerase chain and western blotting. The present study also examined the protein kinase B (Akt) signaling pathway by western blotting. Treatment with 25 or 50 µM paeoniflorin markedly decreased the release of LDH and the ratio of apoptotic cells in interleukin (IL)-1β-induced rat chondrocytes. Paeoniflorin treatment decreased the mRNA and protein levels of Bax, and increased the level of Bcl-2. Paeoniflorin also reduced the activity of caspase-3 in chondrocytes. Furthermore, paeoniflorin was determined to regulate the Akt signaling pathway by increasing Akt phosphorylation. Therefore, paeoniflorin may exert its protective effect by inhibiting apoptosis in IL-1β-induced rat chondrocytes and thus, may be an effective agent in the prevention and treatment of OA.

CTHRC1 mediates IL‑1β‑induced apoptosis in chondrocytes via JNK1/2 signaling

Osteoarthritis (OA), also known as degenerative joint disease or degenerative arthritis, is characterized by chondrocyte apoptosis. The aim of the present study was to investigate the effects of collagen triple helix repeat containing 1 (CTHRC1) and the c‑Jun N‑terminal kinase (JNK) 1/2 inhibitor SP600125 on rat chondrocytes cultured in vitro with interleukin (IL)‑1β. Chondrocytes were treated with different doses of IL‑1β and cell viability and CTHRC1 expression were assessed using Cell Counting Kit‑8 and western blot assays, respectively. In separate experiments, chondrocytes were treated with CTHRC1‑expressing constructs (pLVX‑Puro‑CTHRC1) and/or SP600125, or IL‑1β with either CTHRC1 short hairpin (sh)RNA constructs (shNRA‑CTHRC1) or SP600125. The expression of CTHRC1, B‑cell lymphoma (Bcl)‑2, Bcl‑2‑associated X protein (Bax), cleaved caspase‑3, poly ADP ribose polymerase (PARP)‑1 and matrix metalloproteinase (MMP)‑13 was measured using reverse transcription‑quantitative polymerase chain reaction and western blotting assays. A Cell Counting Kit‑8 assay was performed to examine cell viability. Annexin V/propidium iodide staining and flow cytometry assays were used to detect chondrocyte apoptosis. The expression of JNK1/2 and phosphorylated JNK1/2 was measured using western blotting. CTHRC1 was highly expressed in patients with OA compared with normal controls. IL‑1β treatment (5, 10 and 20 ng/ml) increased the protein expression of CTHRC1 in a dose‑dependent manner and decreased the viability of chondrocytes in a time‑dependent manner. pLVX‑Puro‑CTHRC1 mimics the effect of IL‑1β on chondrocyte apoptosis and JNK1/2 activity, and this is reversed by SP600125 treatment. However, transfection with shRNA‑CTHRC1 or treatment with SP600125 inhibited IL‑1β‑induced cell apoptosis and JNK1/2 activation. These results indicate that CTHRC1 downregulation may protect chondrocytes from IL‑1β‑induced apoptosis by inactivating the JNK1/2 pathway.

Analysis of DNA methylation in chondrocytes in rats with knee osteoarthritis

BACKGROUND

Knee osteoarthritis (KOA) is a degenerative knee disease commonly found in the ageing population. DNA methylation works with histone acetylation to participate in aging. Alterations of DNA methylation may involve the joint chondrocyte degeneration in KOA. The aim of this study is to detect DNA methylation changes in chondrocytes of rats with KOA.

METHODS

The rat KOA model was established with the Hulth method (n = 10), while rats receiving sham operation served as the control (n = 10). At 16 weeks after modeling, the knee joint tissue was collected from half of the rats in each group for Micro-CT scanning, Haematoxylin& Eosin (HE) staining, ABH/OG staining, immunohistochemistry for Bax, Bcl-2 and Fas, and TUNNEL staining. Meanwhile, the articular cartilage was collected from the other half to detect promoter methylation in target genes with the MethylTarget approach.

RESULTS

Micro-CT scanning, HE staining, ABH/OG staining, immunohistochemistry, and TUNNEL staining all showed more severe cartilage injury in the KOA group than in the control group, indicating successful establishment of KOA model. The methylation rate in the KOA group was significantly decreased for C/ebpα-2 (within a CpG island -452 bp to the initiation codon on chromosome 1 91,363,511), Cdk2 (within a CpG island -55 bp to the initiation codon on chromosome 7 3,132,362), Bak1 (within a CpG island 6452 bp to the initiation codon on chromosome 20 5,622,277), and Fas (within a CpG island on the entire chromosome 1 gene), compared with the sham group (P = 0.005, 0.008, 0.022 and 0.027, respectively).

CONCLUSION

The chondrocyte apoptosis and significantly reduced methylation levels of C/ebpα-2, Cdk2, Bak1, and Fas may participate in the pathogenesis of KOA. However, the exact mechanisms remain to be determined.

Insights on Molecular Mechanisms of Chondrocytes Death in Osteoarthritis

Osteoarthritis (OA) is a joint pathology characterized by progressive cartilage degradation. Medical care is mainly based on alleviating pain symptoms. Compelling studies report the presence of empty lacunae and hypocellularity in cartilage with aging and OA progression, suggesting that chondrocyte cell death occurs and participates to OA development. However, the relative contribution of apoptosis per se in OA pathogenesis appears complex to evaluate. Indeed, depending on technical approaches, OA stages, cartilage layers, animal models, as well as in vivo or in vitro experiments, the percentage of apoptosis and cell death types can vary. Apoptosis, chondroptosis, necrosis, and autophagic cell death are described in this review. The question of cell death causality in OA progression is also addressed, as well as the molecular pathways leading to cell death in response to the following inducers: Fas, Interleukin-1β (IL-1β), Tumor Necrosis factor-α (TNF-α), leptin, nitric oxide (NO) donors, and mechanical stresses. Furthermore, the protective role of autophagy in chondrocytes is highlighted, as well as its decline during OA progression, enhancing chondrocyte cell death; the transition being mainly controlled by HIF-1α/HIF-2α imbalance. Finally, we have considered whether interfering in chondrocyte apoptosis or promoting autophagy could constitute therapeutic strategies to impede OA progression.

Expression and Significance of High-Mobility Group Protein B1 (HMGB1) and the Receptor for Advanced Glycation End-Product (RAGE) in Knee Osteoarthritis

Background

This study was performed with the aim to explore the expression of high-mobility group protein B1 (HMGB1) and the receptor for advanced glycation end-product (RAGE) in knee osteoarthritis (KOA) and its clinical significance.

Material/Methods

A total of 108 synovial tissues selected from KOA patients were included in the experimental group. Seventy-five synovial tissues of knee joints, selected from patients who were clinically and pathologically confirmed without joint lesion, were included in the control group. The mRNA and protein expressions of HMGB1 and RAGE were determined by using RT-PCR and immunohistochemistry, respectively. Western blotting was used for measuring relative protein expression. An ROC curve was drawn to evaluate the diagnostic value of HMGB1 and RAGE for KOA.

Results

The positive cell number and positive expression intensity of HMGB1 and RAGE in synovial tissue was higher in the experimental group than in the control group. PI for HMGB1 and RAGE expression in KOA patients was positively correlated with clinical classification of X-ray films (P<0.05). HMGB1 and RAGE mRNA expressions, as well as relative protein expression of HMGB1 and RAGE in synovial tissue, were higher in the experimental group than in the control group (all P<0.05). The sensitivity of HMGB1 protein, RAGE protein, HMGB1 mRNA, and RAGE mRNA were 76.9%, 64.8%, 86.1%, and 64.8%, respectively; and the specificity was 100%, 96%, 74.7%, and 80%, respectively.

Conclusions

The protein and mRNA expressions of HMGB1 and RAGE are both increased in KOA patients, suggesting that they are involved in KOA.

An in vitro investigation into the role of bone marrow‑derived mesenchymal stem cells in the control of disc degeneration

Excessive apoptosis and high expression levels of interleukin-1β (IL-1β) in disc cells have been reported to serve important roles in intervertebral disc degeneration (IVDD). Previous studies investigating mesenchymal stem cells (MSCs) have indicated potential for their use in the treatment of IVDD. However, the therapeutic potential and anti-apoptotic ability of MSCs remains to be fully elucidated. The present study aimed to establish an in vitro model for bone marrow-derived MSC (BMSC) therapy by investigating the anti-apoptotic effects, in addition to the migration of BMSCs to nucleus pulposus (NP) cells stimulated by IL-1β. A co-culture system of BMSCs and NP cells was founded. Following inflammatory stimulation, the NP cells exhibited increased indexes for inflammation-induced degeneration. The degenerative and apoptotic indexes were significantly reduced when NP cells were co-cultured with BMSCs. Compared with the indirect co-culture group, the direct co-culture group exhibited an improved capacity for anti-apoptosis. In addition, IL-1β-stimulated NP cells attracted and mediated the migration of BMSCs. Mitochondrial transfer from BMSCs to NP cells by tunneling nanotubes was also observed. In conclusion, the anti-apoptosis and the migration, in addition to mitochondrial transfer associated with BMSC treatments in IVDD, were investigated in vitro in the present study. The interaction between stimulated NP cells and BMSCs is likely involved in to simulating the in vivo process of stem cell-mediated repair.