Resveratrol Improves the Progression of Osteoarthritis by Regulating the SIRT1-FoxO1 Pathway-Mediated Cholesterol Metabolism.

Osteoarthritis (OA) is considered a metabolic disorder. This study investigated the effect of resveratrol (RES) on cholesterol accumulation in osteoarthritic articular cartilage via the silent information regulator 1 (SIRT1)/forkhead transcription factor (FoxO1) pathway. Interleukin (IL)-1ß-treated chondrocytes that mimic OA chondrocytes were used in in vitro experiments. The optimal RES concentration was selected based on the results of chondrocyte proliferation in the Cell Counting Kit-8 assay. Western blotting, immunofluorescence, and reverse transcription-quantitative polymerase chain reaction were performed. For the animal experiments, mice were randomly divided into the RES group (n = 15), medial meniscus destabilization group (n = 15), and sham group (n = 15), and each group received the same dose of RES or saline. Articular cartilage tissue was obtained eight weeks after surgery for relevant histological analysis. Clinical tissue test results suggest that downregulation of the SIRT1/FoxO1 pathway is associated with cholesterol buildup in OA chondrocytes. For the in vitro studies, RES increased the expression of SIRT1 and phosphorylation of FoxO1 in IL-1ß-treated chondrocytes, promoted the expression of cholesterol efflux factor liver X receptor alpha (LXRα), and inhibited the expression of cholesterol synthesis-associated factor sterol-regulatory element binding proteins 2 (SREBP2). This reduced IL-1ß-induced chondrocytes cholesterol accumulation. SIRT1 inhibition prevented the RES-mediated reduction in cholesterol buildup. Inhibiting FoxO1 but not SIRT1 reduced FoxO1 phosphorylation and increased cholesterol buildup in cultured chondrocytes. Additionally, in vivo experiments have shown that RES can alleviate cholesterol buildup and pathological changes in OA cartilage. Our findings suggest that RES regulates cholesterol buildup in osteoarthritic articular cartilage via the SIRT1/FoxO1 pathway, thereby improving the progression of OA.

Metformin mitigates cholesterol accumulation via the AMPK/SIRT1 pathway to protect osteoarthritis chondrocytes.

In this study, we aim to investigate the effect of metformin on cholesterol synthesis and efflux-related genes in chondrocytes during osteoarthritis (OA) and explore the underlying mechanisms. Primary chondrocytes were harvested from Wistar rat cartilage and divided into control and treatment groups. Chondrocytes in the treatment group were treated with interleukin-1ß (IL-1ß) mimicking the inflammatory environment of osteoarthritis. Subsequently, RT-qPCR, Western blotting, immunofluorescence staining, and Cell Counting Kit-8 (CCK-8) were conducted. Significant reductions in phosphorylated AMP-activated protein kinase (p-AMPK) and silent information regulator 1 (SIRT1) protein expression were observed in both human OA chondrocytes and cultured primary murine chondrocytes treated with IL-1ß, while AMP-activated protein kinase (AMPK) was not inhibited. Moreover, in the presence of IL-1ß, metformin significantly increased the expression of p-AMPK and SIRT1 at the protein and mRNA level. Meanwhile, metformin could reverse IL-1ß-induced cartilage extracellular matrix degradation in chondrocytes from the rat model of OA (treated by IL-ß) by activating the AMPK/SIRT1 pathway. Moreover, metformin activated AMPK and SIRT1, mediated by the activation of SREBP-2 and HMGCR in OA chondrocytes. Inhibiting AMPK/SIRT1 activity by its specific inhibitor could suppress IL-1ß-induced expression of LXRα, ABCA1 and ApoA1 and cholesterol efflux. Thus, metformin inhibits cholesterol synthesis and promotes cholesterol efflux by activating the AMPK/SIRT1 pathway in OA chondrocytes. This study improves our understanding of the effect of metformin on cholesterol accumulation in OA chondrocytes.

Resveratrol protection against IL-1ß-induced chondrocyte damage via the SIRT1/FOXO1 signaling pathway.

PURPOSE: Osteoarthritis (OA) is a common joint disease characterized by cartilage degeneration, synovial inflammation, osteophytes, and subchondral osteosclerosis. This study investigated the effects of resveratrol (RES) on extracellular matrix (ECM), autophagy, and apoptosis in OA pathogenesis via the SIRT1/FOXO1 pathway. METHODS: The microenvironment of OA chondrocytes was stimulated in vitro by adding 10 ng/mL of IL-1ß to primary Wistar rat chondrocyte. Western blotting, immunofluorescence, quantitative real-time PCR, and transmission electron microscopy (TEM) were used for analysis. RESULTS: In the presence of IL-1ß, RES increased the expression of silent information regulator (SIR) 1 protein and the phosphorylation level of forkhead transcription factor (FOXO) 1. It also promoted chondrocyte autophagy, increased the expression of SOX9 and aggrecan, inhibited chondrocyte apoptosis and matrix breakdown, and protected chondrocytes from IL-1ß damage. After a SIRT1 inhibitor or FOXO1 inhibitor was added, the protective effect of RES on chondrocytes was significantly weakened. Our results suggest that RES regulates the ECM metabolism, autophagy, and apoptosis of OA chondrocytes through the SIRT1/FOXO1 pathway to ameliorate IL-1ß-induced chondrocyte injury. CONCLUSION: RES protects chondrocytes from IL-1ß-induced damage by activating SIRT1/FOXO1 signaling and holds potential in OA treatment.

Effect of DNA methylation on gene transcription is associated with the distribution of methylation sites across the genome in osteoarthritis.

Genetics and epigenetics are important subjects in the field of osteoarthritis (OA) research. DNA methylation may affect gene transcription, but the specific mechanisms have remained to be fully elucidated. In the present study, the ChAMP methylation analysis package was used to identify differentially methylated genes (DMGs) from the dataset GSE63695 from the Gene Expression Omnibus (GEO) database. The distribution of differentially methylated sites (DMS) and the total array sites across the genome were analyzed by enrichment analysis. Subsequently, two mRNA expression profiling datasets, GSE114007 and GSE113825, were obtained from the GEO database and common differentially expressed genes (DEGs) were identified using the Limma package. Key genes were screened by analyzing the distribution of DMS across the genome consisting of DEGs and DMGs. A total of 1,662 and 1,986 DEGs were identified between OA and normal human cartilage from the GSE113825 and GSE114007 dataset, respectively. A further screening revealed 292 genes with common differences between the two datasets. A total of 574 DMS containing 394 DMGs were observed between OA and normal cartilage. Integrative analysis revealed a corresponding subset of 15 genes. Of these, 6 genes were verified by reverse transcription-quantitative PCR, confirming that the mRNA expression of 5 genes (MAP1B, FNDC1, ANLN, SCNN1A and STC2) in OA cartilage was consistent with the mRNA expression from the analysis of the datasets. Upon treatment with the DNA methylation inhibitor 5-aza-2'-deoxycytidine, the mRNA levels of FNDC1 and SCNN1A were decreased, and no significant alteration in the mRNA levels of MAP1B, ANLN, KCNN4 and STC2 was observed. The incidence of differential methylation varied in subregions of the genome and the effects on transcription were associated with the distribution of DEGs across the genome. The regulation of this appears more complex than initially postulated. Combining the data on epigenetic differences of OA with the genome or transcriptome data for analysis may improve the understanding of the pathophysiological processes of OA. FNDC1 and SCNN1A may potentially be valuable biomarkers for OA.

Analysis of mRNA Expression and DNA Methylation Datasets According to the Genomic Distribution of CpG Sites in Osteoarthritis.

Objectives Transcriptional changes in cartilage can impact function by causing degradation such as that which occurs during the development of osteoarthritis (OA). Epigenetic regulation may be a key factor leading to transcriptional changes in OA. In this study, we performed a combined analysis of DNA methylation and gene expression microarray datasets and identified key transcription factors (TFs) central to the regulation of gene expression in OA. Methods A DNA methylation profile dataset (GSE63106) and a gene expression profiling dataset (GSE114007) were extracted from the Gene Expression Omnibus (GEO). We used ChAMP methylation analysis and the Limma package to identify differentially methylation genes (DMGs) and differentially expressed genes (DEGs) from normal and human knee cartilage samples in OA. Function enrichment analysis of DMGs was conducted using the DAVID database. A combined analysis of DEGs and DMGs was conducted to identify key TFs in OA. We then validated the mRNA expression of selected TFs in normal and OA cartilage by RT-qPCR. Primary chondrocytes were cultured and treated with the DNA methylation inhibitor 5-Aza-2-deoxycytidine (5-Aza) for functional validation. Results We identified 2,170 differential methylation sites (DMS) containing 1005 genes and 1986 DEGs between normal human and OA cartilage. Functional analysis of DMGs revealed that focal adhesion, extracellular matrix (ECM)-receptor interactions, the PI3K-Akt signaling pathway, and the FoxO signaling pathway were involved in OA. Integrated analysis showed a subset of 17 TFs. Four TFs (ELF3, SOX11, RARA, and FOXD2) were validated. RT-qPCR results showed the mRNA expression of SOX11, RARA, and FOXD2 were consistent with the results from the mRNA expression data. However, the expression of ELF3 could not be validated. Upon 5-Aza-2'-deoxycytidine (5-Aza) treatment, the mRNA levels of ELF3 and SOX11 were down-regulated, whilst RARA was up-regulated, and FOXD2 showed no significant change in expression level. Conclusions the effect of DNA methylation on the transcriptional regulation is related to the distribution of methylated sites across the genome. Epigenetic studies on the positions of DMS in transcriptional units can inform a better understanding of the function of DNA methylation and its transcription regulation.

Impact of chitosan membrane culture on the expression of pro- and anti-inflammatory cytokines in mesenchymal stem cells.

Osteoarthritis (OA) is a chronic inflammatory joint condition caused by various inflammatory cytokines. The pro-inflammatory cytokines controlling OA include interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, IL-6 and IL-18. The anti-inflammatory cytokines include IL-4, IL-10, IL-13, leukemia inhibitory factor (LIF), glycoprotein 130 (IL6ST), TNF-α-stimulated gene 6 and transforming growth factor (TGF)-ß1. Mesenchymal stem cells (MSCs) serve an anti-inflammatory role in the treatment of OA by secreting various cytokines. Previous studies demonstrated that the anti-inflammatory ability of MSCs decreased rapidly in a traditional plate culture. Maintaining the anti-inflammatory properties of MSCs in vitro remains challenging. Therefore, it is necessary to develop a more stable and efficient method to culture MSCs in vitro. Chitosan is a deacetylated derivative of chitin and is the second most abundant natural polysaccharide worldwide. The present study demonstrated that that MSCs cultured on chitosan membranes (CM) spontaneously formed multicellular spheroids. Compared with the control group without CM, the formation of multicellular spheres in the CM enhanced the anti-inflammatory properties of MSCs. Expression levels of pro- and anti-inflammatory genes mRNA and their proteins in MSCs were detected by reverse transcription-quantitative PCR, western blot analysis and immunofluorescence assay. Protein and mRNA expression levels of pro-inflammatory cytokines IL-1ß, TNF-α, IL-6 and IL-18 were significantly decreased in CM-cultured MSCs compared with the control group (P<0.05). Furthermore, mRNA and protein expression levels of anti-inflammatory cytokines TGF-ß1 in CM-cultured MSCs were significantly increased compared with the control group (P<0.01). These results indicated that the formation of multicellular spheroids by CM-cultured MSCs aided in maintaining anti-inflammatory effects.

Curcumin reinforces MSC-derived exosomes in attenuating osteoarthritis via modulating the miR-124/NF-kB and miR-143/ROCK1/TLR9 signalling pathways.

Curcumin treatment was reported to delay the progression of OA, but its underlying mechanism remains unclear. In this study, we aimed to investigate the molecular mechanism underlying the role of curcumin in OA treatment. Accordingly, by conducting MTT and flow cytometry assays, we found that the exosomes derived from curcumin-treated MSCs helped to maintain the viability while inhibiting the apoptosis of model OA cells. Additionally, quantitative real-time PCR and Western blot assays showed that the exosomes derived from curcumin-treated MSCs significantly restored the down-regulated miR-143 and miR-124 expression as well as up-regulated NF-kB and ROCK1 expression in OA cells. Mechanistically, curcumin treatment decreased the DNA methylation of miR-143 and miR-124 promoters. In addition, the 3' UTRs of NF-kB and ROCK1 were proven to contain the binding sites for miR-143 and miR-124, respectively. Therefore, the up-regulation of miR-143 and miR-124 in cellular and mouse OA models treated with exosomes remarkably restored the normal expression of NF-kB and ROCK1. Consequently, the progression of OA was attenuated by the exosomes. Our results clarified the molecular mechanism underlying the therapeutic role of MSC-derived exosomes in OA treatment.

Near-perfect kinetic resolution of o-methylphenyl glycidyl ether by RpEH, a novel epoxide hydrolase from Rhodotorula paludigena JNU001 with high stereoselectivity.

In order to provide more alternative epoxide hydrolases for industrial production, a novel cDNA gene Rpeh-encoding epoxide hydrolase (RpEH) of Rhodotorula paludigena JNU001 identified by 26S rDNA sequence analysis was amplified by RT-PCR. The open-reading frame (ORF) of Rpeh was 1236 bp encoding RpEH of 411 amino acids and was heterologously expressed in Escherichia coli BL21(DE3). The substrate spectrum of expressed RpEH showed that the transformant E. coli/Rpeh had excellent enantioselectivity to 2a, 3a, and 5a-10a, among which E. coli/Rpeh had the highest activity (2473 U/g wet cells) and wonderful enantioselectivity (E = 101) for 8a, and its regioselectivity coefficients, αR and ßS, toward (R)- and (S)-8a were 99.7 and 83.2%, respectively. Using only 10 mg wet cells/mL of E. coli/Rpeh, the near-perfect kinetic resolution of rac-8a at a high concentration (1000 mM) was achieved within 2.5 h, giving (R)-8a with more than 99% enantiomeric excess (ees) and 46.7% yield and producing (S)-8b with 93.2% eep and 51.4% yield with high space-time yield (STY) for (R)-8a and (S)-8b were 30.6 and 37.3 g/L/h.

Overexpression of miR-206 in osteosarcoma and its associated molecular mechanisms as assessed through TCGA and GEO databases.

Osteosarcoma (OS) is a primary malignant bone tumor that predominantly occurs in adolescents. Different types of OS tumor are highly malignant, associated with a poor prognosis and are invasive with blood-vessel dissemination characteristics, thus affected patients are prone to early lung metastasis. MicroRNAs (miRNAs/miR) are small non-coding RNA molecules that act as oncogenes or tumor suppressors during tumor development. The present study investigated the role of miR-206 in OS development. Bioinformatics analysis demonstrated that miR-206 was upregulated in OS and thus may serve as a risk factor for cancer prognosis. Subsequently, in response to miR-206 overexpression, differentially expressed genes were screened and analyzed using the Database for Annotation, Visualization and Integrated Discovery, Gene Ontology enrichment analysis, the Kyoto Encyclopedia of Genes and Genomes pathways and protein-protein interaction network construction, in order to identify key miR-206 targets. The results demonstrated that high miR-206 expression inhibited OS cell proliferation, which was associated with a good patient prognosis. Thus, miR-206 may serve as a potential target for OS treatment, in order to improve early disease diagnosis.

Near-perfect kinetic resolution of racemic p-chlorostyrene oxide by SlEH1, a novel epoxide hydrolase from Solanum lycopersicum with extremely high enantioselectivity.

An open reading frame of sleh1, a gene encoding for a novel epoxide hydrolase from Solanum lycopersicum (SlEH1), was amplified by RT-PCR and expressed in E. coli BL21(DE3). The substrate spectrum assay showed that E. coli/sleh1 had EH activities towards all tested substrates except for racemic (rac-) 5a, and the highest enantiomeric ratio (E > 200) towards rac-2a, retaining (R)-2a with 99.1% ees and 49.2% yields and affording (R)-2b with 89.8% eep and 46.7% yieldp. Besides, E. coli/sleh1 also hydrolyzed of rac-7a-9a with moderate regioselectivities, producing (S)- or (R)-7b-9b with 40.5-51.3% eep and 69.4-75.2% yieldp. The pH optimum and stability of the purified SlEH1 were 7.5 and at a range of 6.5-8.5, and it was thermostable at or below 40 °C. Its catalytic efficiency (kcatS/KmS = 7.49 mM-1 s-1) for (S)-2a was much higher than that for (R)-2a. The gram-scale kinetic resolution of 150 mM rac-2a was carried out by E. coli/sleh1 at 20 °C for 8 h, producing (R)-2a with 98.2% ees and 45.3% overall yields after purification by silica gel column chromatography. Furthermore, the source of extremely high enantioselectivity of SlEH1 towards rac-2a was analyzed by molecular docking simulations.

A review of fibroblast growth factor 21 in diabetic cardiomyopathy.

FGF21 (fibroblast growth factor 21) is a regulator of metabolism and performs an important role in glucose and lipid metabolism and the maintenance of energy balance. FGF21 is principally expressed in the liver, but it can also be found in the pancreas, skeletal muscle, and adipose tissue. It is known that levels of serum FGF21 are significantly elevated in obese, insulin-resistant patients, and those with metabolic syndrome. Elevated levels of FGF21 in serum during the early stages of various metabolic diseases are considered a compensatory response by the organism. Therefore, FGF21 is considered a hormone in response to stress and an early diagnostic marker of disease. Diabetic cardiomyopathy is a special type of cardiac complication, characterized as a chronic myocardial disorder caused by diabetes. The pathological process includes increased oxidative stress, energy metabolism in myocardial cells, an inflammatory response, and myocardial cell apoptosis. A growing body of evidence suggests that FGF21 has the potential to be an effective drug for the treatment of diabetic cardiomyopathy. Here, we review recent progress on the characteristics of FGF21 in its protective role, especially in pathological processes such as suppressing apoptosis in the myocardium, reducing inflammation in cardiomyocytes, reducing oxidative stress, and promoting fatty acid oxidation. In addition, we explore the possibility that diabetic cardiomyopathy can be delayed through the application of FGF21, providing possible therapeutic targets of the disease.

Construction of chitosan/ZnO nanocomposite film by in situ precipitation.

In the present work, flexible chitosan/ZnO nanocomposite films were prepared by a green and facile method through in situ precipitation of nano-ZnO (nZnO) in the chitosan film. Zn(Ac)2 was added in chitosan solution to provide Zn2+, thus Zn2+ was fixed in the chitosan matrix and converted into nZnO through interaction with NaOH with heating. The structure and properties of the hybrid films were characterized by Field emission scanning electron microscope (FESEM), atomic force microscope (AFM), Fourier transform infra-red (FT-IR), X-ray diffraction (XRD) and tensile testing. The results indicated that there was strong coordination interaction existed between Zn2+ and chitosan matrix for the good dispersion of nZnO in the chitosan film. Furthermore, nZnO distributed evenly in the chitosan and aggregated to form micro-nano-binary hierarchical structure, mimicking lotus leaf structure. Therefore, this work provides an effective way to prepare biocompatible and antibacterial chitosan/ZnO nanocomposite films, showing potential applications in the fields of antibacterial packaging and dressings.

Hyaluronic acid-chitosan nanoparticles encoding CrmA attenuate interleukin-1ß induced inflammation in synoviocytes in vitro.

Osteoarthritis (OA) is a common degenerative joint disease characterized by inflammation of synoviocytes and degradation of cartilage. In the present study, hyaluronic acid/chitosan (HA/CS) nanoparticles were used as a vehicle for gene therapy of OA, and the cytokine response modifier A (CrmA) pDNA was proposed as the target gene. The HA/CS/pCrmA nanoparticles were prepared and the characteristics of the nanoparticles were examined. The nanoparticles were spherical, and the smallest size was obtained with the HA:CS weight ratio of 1:4. The release analysis exhibited a constant release over 29 days. The pDNA was completely combined with HA/CS nanoparticles and the HA/CS nanoparticles protected pDNA from degradation. Subsequently, rat synoviocytes were transfected with HA/CS/pDNA nanoparticles, and the results demonstrated that the HA/CS nanoparticles were able to improve the transfection capacity of pDNA. The cytotoxicity of the HA/CS/pDNA nanoparticles was additionally detected using a MTS assay to ensure that the HA/CS nanoparticle was a safe carrier. To additionally investigate the effects of HA/CS/pCrmA nanoparticles on synoviocytes in OA, the MMP­3 and MMP­13 gene expression levels were detected at the gene and protein expression levels. These results indicated that the HA/CS/pCrmA nanoparticles attenuated interleukin­1ß­mediated inflammation in synoviocytes. It was concluded that the HA/CS/pCrmA nanoparticles may provide a novel approach to the treatment of OA.

Chondroprotective Effects of Hyaluronic Acid-Chitosan Nanoparticles Containing Plasmid DNA Encoding Cytokine Response Modifier A in a Rat Knee Osteoarthritis Model.

BACKGROUND/AIMS: Interleukin (IL)-1ß plays an essential role in the pathophysiology of osteoarthritis (OA). Cytokine response modifier A (CrmA) can prevent the generation of active IL-1ß. This study aimed to explore the chondroprotective effects of hyaluronic acid-chitosan nanoparticles containing plasmid DNA encoding CrmA (HA/CS-CrmA) in a rat OA model. METHODS: HA/CS-CrmA nanoparticles were synthesized through the complex coacervation of cationic polymers. The characteristics, toxicity, and transfection of the nanoparticles were investigated. Furthermore, the potential effects of HA/CS-CrmA nanoparticles were evaluated via a rat anterior cruciate ligament transection (ACLT) model of OA. Cartilage damage and synovial inflammation were assessed by safranin O/fast green and hematoxylin and eosin staining. Type II collagen in cartilage was measured by immunohistochemistry, and the expression levels of IL-1ß, matrix metalloproteinase (MMP)-3, and MMP-13 in synovial tissue were detected by western blot. RESULTS: The HA/CS-CrmA nanoparticles, which effectively entrapped plasmid DNA, showed an adequate size (100-300 nm) and a regular spherical shape. The nanoparticles safely transfected synoviocytes and released plasmid DNA in a sustained manner over 3 weeks. Additionally, HA/CS-CrmA nanoparticles significantly inhibited cartilage damage, synovial inflammation, and the loss of type II collagen induced by ACLT. The expression levels of IL-1ß, MMP-3, and MMP-13 in synovial tissue were dramatically down-regulated by HA/CS-CrmA nanoparticles. CONCLUSIONS: These results suggested that HA/CS-CrmA nanoparticles could attenuate cartilage destruction and protect against early OA by inhibiting synovial inflammation via inhibition of IL-1ß generation.

Tristetraprolin: A novel target of diallyl disulfide that inhibits the progression of breast cancer.

Diallyl disulfide (DADS), a volatile component of garlic oil, has various biological properties, including antioxidant, antiangiogenic and anticancer effects. The present study aimed to explore novel targets of DADS that may slow or stop the progression of breast cancer. First, xenograft tumor models were created by subcutaneously injecting MCF-7 and MDA-MB-231 breast cancer cells into nude mice. Subsequently, western blot analysis was performed to investigate the expression of tristetraprolin (TTP), urokinase-type plasminogen activator (uPA) and matrix metalloproteinase-9 (MMP-9) in the xenograft tumors, and cell cultures. Tablet cloning, Transwell and wound healing assays revealed that DADS treatment significantly inhibited the proliferation, invasion and migration of breast cancer cells. In addition, DADS treatment led to significant downregulation of uPA and MMP-9 protein expression, but significantly upregulated TTP expression in vivo and in vitro. Knocking down TTP expression using small interfering RNA reversed the aforementioned effects of DADS, which suggests TTP is a key target of DADS in inhibiting the progression of breast cancer.