Visfatin Promotes IL-6 and TNF-α Production in Human Synovial Fibroblasts by Repressing miR-199a-5p through ERK, p38 and JNK Signaling Pathways

MicroRNA-199a-5p may be a diagnostic biomarker of primary ITP

There is no diagnostic test for primary immune thrombocytopenia (ITP). Certain microRNAs have shown to have diagnostic potential in ITP. We validated 12 microRNAs identified from two previous studies to find a diagnostic biomarker. The study included two ITP cohorts (n = 61) and healthy controls (n = 28). The first ITP cohort involved 24 patients from the Prolong study, patients with newly diagnosed/persistent ITP (<1 year) treated with corticosteroids ± IVIG but relapsed/failed to respond. The second cohort comprised 37 patients from ITP biobank, Østfold Hospital, Norway, patients had different disease stages and therapies. Twelve microRNAs were measured: miR-199a-5p, miR-33a-5p, miR-195-5p, miR-130a-3p, miR-144-3p, miR-146a-5p, miR-222-3p, miR-374b-5p, miR-486-5p, miR-1341-5p, miR-766-3p and miR-409-3p. miR-199a-5p, miR-33a-5p, miR-374b-5p, miR-146a-5p and miR-409-3p were expressed differentially in the entire ITP cohort compared to controls; of those only miR-199a-5p showed good discriminative ability between ITP and controls with area under the curve (AUC) of 0.718 (95% CI: 0.599-0.836). In the Prolong cohort (ITP < 1 year), miR-199a-5p and miR-374b-5p showed very good discriminative ability between ITP and controls with AUC of 0.824 (0.708-0.940) and 0.806 (0.688-0.924) respectively. This study confirmed that miR-199a-5p has good discriminative ability between primary ITP and healthy controls, thus may be a diagnostic biomarker of ITP.

The Role of Extracellular Vesicles in the Development and Treatment of Psoriasis: Narrative Review

Psoriasis is a chronic inflammatory polygenic disease with significant impacts on skin and joints, leading to substantial treatment challenges and healthcare costs. The quest for novel therapeutic avenues has recently highlighted extracellular vesicles (EVs) due to their potential as biomarkers and therapeutic agents in autoimmune diseases, including psoriasis. EVs are nano-sized, lipid membrane-bound particles secreted by cells that have emerged as promising tools for targeted drug delivery, owing to their unique structure. This review delves into how EVs, either as mediators of cell communication or via their cargo (such as miRNA), directly participate in the pathology of psoriasis, influencing processes such as immune regulation, cell proliferation, and differentiation. Furthermore, this review explores the innovative application of EVs in psoriasis treatment, both as direct therapeutic agents and as vehicles for drug delivery, offering a novel approach to overcoming the current treatment limitations.

Cellular and molecular mechanisms underlying obesity in degenerative spine and joint diseases

Degenerative spine and joint diseases, including intervertebral disc degeneration (IDD), ossification of the spinal ligaments (OSL), and osteoarthritis (OA), are common musculoskeletal diseases that cause pain or disability to the patients. However, the pathogenesis of these musculoskeletal disorders is complex and has not been elucidated clearly to date. As a matter of fact, the spine and joints are not independent of other organs and tissues. Recently, accumulating evidence demonstrates the association between obesity and degenerative musculoskeletal diseases. Obesity is a common metabolic disease characterized by excessive adipose tissue or abnormal adipose distribution in the body. Excessive mechanical stress is regarded as a critical risk factor for obesity-related pathology. Additionally, obesity-related factors, mainly including lipid metabolism disorder, dysregulated pro-inflammatory adipokines and cytokines, are reported as plausible links between obesity and various human diseases. Importantly, these obesity-related factors are deeply involved in the regulation of cell phenotypes and cell fates, extracellular matrix (ECM) metabolism, and inflammation in the pathophysiological processes of degenerative spine and joint diseases. In this study, we systematically discuss the potential cellular and molecular mechanisms underlying obesity in these degenerative musculoskeletal diseases, and hope to provide novel insights for developing targeted therapeutic strategies.

Visfatin and VEGF levels are not increased in adolescent girls with polycystic ovary syndrome

Introduction

PCOS is one of the most commonly occurring endocrinopathies among women and increasingly affects adolescent populations. The connection between PCOS and various endocrinological, psychological, and CVD is increasingly recognized. Some studies have shown elevated levels of visfatin and VEGF among patients with PCOS, which are markers of vascular endothelial dysfunction. In our study, we evaluated the concentration of these parameters, focusing solely on a group of adolescents with PCOS, to assess whether these early markers of CVD are present at an early stage of diagnosis.

Material and methods

In total, 80 adolescent girls participated in the study. 47 adolescents diagnosed with PCOS were included in the study group (mean age 15.68 ± 1.18 years, BMI 26.66 ± 6.41 kg/m2), while the remaining 33 regularly menstruating individuals (mean age 15.79 ± 1.22 years, BMI 25.44 ± 7.24 kg/m2) were assigned to the control group. Each participant underwent imaging, biochemical, and hormonal tests. Additionally, markers of endothelial dysfunction: VEGF and visfatin, were measured in all adolescents.

Results

Both VEGF and visfatin levels did not differ significantly between PCOS and control group (p=0.30 and p=0.15, respectively). In the group of adolescent girls with PCOS, visfatin was significantly correlated with HDL, FSH, cortisol, and testosterone levels >55 ng/dl. VEGF was significantly correlated with fasting glucose, glucose levels after OGTT, estradiol, and waist circumference >80 cm.

Conclusion

It can be indirectly inferred that both visfatin and VEGF should not be used as early markers for cardiometabolic complications among adolescent patients with PCOS. On the other hand, low visfatin levels, through their negative correlation with HDL, may have a protective effect on cardiovascular complications, while low VEGF levels, through their positive correlation with glucose levels, may have a protective influence on carbohydrate metabolism disorders.

Genetic associations of visfatin polymorphisms with clinicopathologic characteristics of prostate cancer in Taiwanese males

The most general cancer in men is prostate cancer (PCa), with its risk increasing due to age and obesity. Visfatin, a member of adipokines, is related to cancer progression and metastasis, but its relationship in PCa remains undetermined. In addition, no knowledge is available regarding relations between visfatin polymorphisms and clinicopathological characteristics in PCa. We sought to investigate the functions of four visfatin gene polymorphisms and clinicopathological characteristics on the hazard of developing PCa in 695 Taiwanese males with PCa. Carriers of the GA+AA heterozygote of SNP rs61330082 were at a markedly higher risk of biochemical recurrence than those with the GG genotype. Visfatin rs61330082 and rs11977021 were related with a high risk of perineural invasion, lymphovascular invasion, and biochemical recurrence in prostate-specific antigen (PSA) > 10 PCa patients. The Cancer Genome Atlas database noted that visfatin mRNA level did not prominently differ with pathological T/N stage and overall survival. This finding is the first to document a connection between visfatin polymorphisms and clinicopathological characteristics of PCa in Taiwanese males.

Thyroid-stimulating hormone induces insulin resistance in adipocytes via endoplasmic reticulum stress

Graphical abstract

Abstract

Subclinical hypothyroidism (SCH) is closely related to insulin resistance, and thyroid-stimulating hormone (TSH) level is an independent factor for insulin resistance associated with subclinical hypothyroidism. This study aims to explore the effects of TSH levels on insulin signal transduction in adipocytes and to establish the role of endoplasmic reticulum (ER) stress in this process. In this study, the SCH mouse model was established, and 3T3-L1 adipocytes were treated with TSH or tunicamycin (TM), with or without 4-phenylbutyric acid (4-PBA), an inhibitor of ER stress. Subclinical hypothyroidism mice exhibited impaired glucose tolerance, inactivation of the IRS-1/AKT pathway, and activation of the IRE1/JNK pathway in adipose tissue, which can all be alleviated by 4-PBA. Supplementation with levothyroxine restored the TSH to normal, alongside alleviated ER stress and insulin resistance in SCH mice, which is characterized by improved glucose tolerance, decreased mRNA expression of IRE1, and decreased phosphorylation of JNK in adipose tissue. In 3T3-L1 adipocytes, TSH induces insulin resistance, leading to a decrease in glucose uptake. This effect is mediated by the downregulation of IRS-1 tyrosine phosphorylation, reduced AKT phosphorylation, and inhibited GLUT4 protein expression. Notably, all these effects can be effectively reversed by 4-PBA. Moreover, TSH induced TNF-α and IL-6 production and upregulated the expression of ER stress markers. Similarly, these changes can be recovered by 4-PBA. These findings indicate that TSH has the capability to induce insulin resistance in adipocytes. The mechanism through which TSH disrupts insulin signal transduction appears to involve the ER stress-JNK pathway.

SNHG12/NFYC-AS1 Acted as the Sponge for hsa-miR-199a-5p to Promote the Expression of S100A8/S100A7/XDH and was Involved in the Progression of Diabetic Foot Ulcers

Traditional Chinese medicine has been used to treat diabetic foot ulcer (DFU) for a long time. However, the underlying mechanism of Radix arnebiae seu lithospermi ointment (RAS-ointment) has not been revealed. Effects of RAS-ointment treatment were observed in DFU patients. The endogenous competitive RNA mechanism was constructed based on micro-array sequencing and bioinformatics analysis. RT-PCR was used to detected the expression of genes in DFU ulcerated skins and non-ulcerated skins. Dual luciferase and RT-PCR experiments were used to investigate the endogenous competitive RNA mechanism. Based on micro-array sequencing and bioinformatics analysis, we found that SNHG12/NFYC-AS1, hsa-miR-199a-5p and S100A8/S100A7/XDH might form an endogenous competitive RNA mechanism. RT-PCR assay shown that SNHG12, NFYC-AS1, S100A8, S100A7 and XDH were significantly up-regulated, while hsa-miR-199a-5p was significantly down-regulated in DFU ulcerated skins (N = 10) compared with non-ulcerated skins (N = 10). Dual luciferase and RT-PCR experiments showed that SNHG12 or NFYC-AS1 up-regulated the expression of S100A8, S100A7 and XDH by inhibiting hsa-miR-199a-5p in a direct binding way. After 35 days of RAS-ointment treatment, the wound healing of DFU patients was substantially improved and the expression of S100A7 and XDH were reduced expression in DFU patients. In addition, the monomer composition of RAS-ointment, 49070_FLUKA or auraptenol inhibited the expression of S100A7 and XDH in Te317.sk cells. In conclusion, RAS-ointment may be used as an adjunctive therapy for DFU patients.

Extracellular nicotinamide phosphoribosyltransferase: role in disease pathophysiology and as a biomarker

Nicotinamide phosphoribosyltransferase (NAMPT) plays a central role in mammalian cell metabolism by contributing to nicotinamide adenine dinucleotide biosynthesis. However, NAMPT activity is not limited to the intracellular compartment, as once secreted, the protein accomplishes diverse functions in the extracellular space. Extracellular NAMPT (eNAMPT, also called visfatin or pre-B-cell colony enhancing factor) has been shown to possess adipocytokine, pro-inflammatory, and pro-angiogenic activities. Numerous studies have reported the association between elevated levels of circulating eNAMPT and various inflammatory and metabolic disorders such as obesity, diabetes, atherosclerosis, arthritis, inflammatory bowel disease, lung injury and cancer. In this review, we summarize the current state of knowledge on eNAMPT biology, proposed roles in disease pathogenesis, and its potential as a disease biomarker. We also briefly discuss the emerging therapeutic approaches for eNAMPT inhibition.

The potential role of synovial cells in the progression and treatment of osteoarthritis

Osteoarthritis (OA), the commonest arthritis, is characterized by the progressive destruction of cartilage, leading to disability. The Current early clinical treatment strategy for OA often centers on anti-inflammatory or analgesia medication, weight loss, improved muscular function and articular cartilage repair. Although these treatments can relieve symptoms, OA tends to be progressive, and most patients require arthroplasty at the terminal stages of OA. Recent studies have shown a close correlation between joint pain, inflammation, cartilage destruction and synovial cells. Consequently, understanding the potential mechanisms associated with the action of synovial cells in OA could be beneficial for the clinical management of OA. Therefore, this review comprehensively describes the biological functions of synovial cells, the synovium, together with the pathological changes of synovial cells in OA, and the interaction between the cartilage and synovium, which is lacking in the present literature. Additionally, therapeutic approaches based on synovial cells for OA treatment are further discussed from a clinical perspective, highlighting a new direction in the treatment of OA.

Obesity, Metabolic Syndrome, and Osteoarthritis-An Updated Review

PURPOSE OF REVIEW

Metabolic syndrome (MetS), also called the 'deadly quartet' comprising obesity, diabetes, dyslipidemia, and hypertension, has been ascertained to have a causal role in the pathogenesis of osteoarthritis (OA). This review is aimed at discussing the current knowledge on the contribution of metabolic syndrome and its various components to OA pathogenesis and progression.

RECENT FINDINGS

Lately, an increased association identified between the various components of metabolic syndrome (obesity, diabetes, dyslipidemia, and hypertension) with OA has led to the identification of the 'metabolic phenotype' of OA. These metabolic perturbations alongside low-grade systemic inflammation have been identified to inflict detrimental effects upon multiple tissues of the joint including cartilage, bone, and synovium leading to complete joint failure in OA. Recent epidemiological and clinical findings affirm that adipokines significantly contribute to inflammation, tissue degradation, and OA pathogenesis mediated through multiple signaling pathways. OA is no longer perceived as just a 'wear and tear' disease and the involvement of the metabolic components in OA pathogenesis adds up to the complexity of the disease. Given the global surge in obesity and its allied metabolic perturbations, this review aims to throw light on the current knowledge on the pathophysiology of MetS-associated OA and the need to address MetS in the context of metabolic OA management. Better regulation of the constituent factors of MetS could be profitable in preventing MetS-associated OA. The identification of key roles for several metabolic regulators in OA pathogenesis has also opened up newer avenues in the recognition and development of novel therapeutic agents.

MiR-320a upregulation improves IL-1β-induced osteoarthritis via targeting the DAZAP1 and MAPK pathways

PURPOSE

Osteoarthritis (OA), a constant illness described by articular cartilage degeneration, usually manifested by joint pain and helpless development. Numerous literatures suggest that microRNAs play an important regulatory role in OA, yet the role of miR-320a in OA remains largely obscure.

MATERIALS AND METHODS

To evaluate the expression of miR-320a mRNA, quantitative real-time polymerase chain reaction was used. Cell counting kit-8 assay, Edu staining, Annexin V-FITC/PI apoptosis detection assay, Caspases 3 staining, and trypan staining were conducted to monitor cell proliferation and apoptosis. Western blot was applied to examine DAZAP1 and ERK/JNK/MAPK associated protein expression. Luciferase reporter gene experiments were performed to confirm the relationships between miR-320a and DAZAP1. ELISA assay was adopted to analyze the secretion of inflammation cytokines IL-6, IL-8, and TNF-α.

RESULTS

In an in vitro osteoarthritis model caused by IL-1β, miR-320a expression was markedly reduced. Overexpression of miR-320a restored IL-1β-inhibited chondrocyte proliferation, induced apoptosis and inflammatory response. Mechanistically, miR-320a affected HC-A cell proliferation, apoptosis and inflammatory response by regulating DAZAPI. Meanwhile, the ERK/JNK/MAPK pathway is also involved in the regulatory role of miR-320a on OA.

CONCLUSION

Our results show an important role for miR-320a and provide new therapeutic targets for avoiding and treating osteoarthritis.

miR-199a-5p Reduces Chondrocyte Hypertrophy and Attenuates Osteoarthritis Progression via the Indian Hedgehog Signal Pathway

Osteoarthritis (OA), the most common type of arthritis, is an age-associated disease, characterized by the progressive degradation of articular cartilage, synovial inflammation, and degeneration of subchondral bone. Chondrocyte proliferation is regulated by the Indian hedgehog (IHH in humans, Ihh in animals) signaling molecule, which regulates hypertrophy and endochondral ossification in the development of the skeletal system. microRNAs (miRNAs, miRs) are a family of about 22-nucleotide endogenous non-coding RNAs, which negatively regulate gene expression. In this study, the expression level of IHH was upregulated in the damaged articular cartilage tissues among OA patients and OA cell cultures, while that of miR-199a-5p was the opposite. Further investigations demonstrated that miR-199a-5p could directly regulate IHH expression and reduce chondrocyte hypertrophy and matrix degradation via the IHH signal pathway in the primary human chondrocytes. The intra-articular injection of synthetic miR-199a-5p agomir attenuated OA symptoms in rats, including the alleviation of articular cartilage destruction, subchondral bone degradation, and synovial inflammation. The miR-199a-5p agomir could also inhibit the Ihh signaling pathway in vivo. This study might help in understanding the role of miR-199a-5p in the pathophysiology and molecular mechanisms of OA and indicate a potential novel therapeutic strategy for OA patients.

Effect of condylar chondrocyte exosomes on condylar cartilage osteogenesis in rats under tensile stress

Background: Functional orthoses are commonly used to treat skeletal Class II malocclusion, but the specific mechanism through which they do this has been a challenging topic in orthodontics. In the present study, we aimed to explore the effect of tensile stress on the osteogenic differentiation of condylar chondrocytes from an exosomal perspective. Methods: We cultured rat condylar chondrocytes under resting and tensile stress conditions and subsequently extracted cellular exosomes from them. We then screened miRNAs that were differentially expressed between the two exosome extracts by high-throughput sequencing and performed bioinformatics analysis and osteogenesis-related target gene prediction using the TargetScan and miRanda softwares. Exosomes cultured under resting and tensile stress conditions were co-cultured with condylar chondrocytes for 24 h to form the Control-Exo and Force-Exo exosome groups, respectively. Quantitative real time PCR(RT-qPCR) and western blotting were then used to determine the mRNA and protein expression levels of Runx2 and Sox9 in condylar chondrocytes. Results: The mRNA and protein expression levels of Runx2 and Sox9 in the Force-Exo group were significantly higher than those in the Control-Exo group (p < 0.05). The differential miRNA expression results were consistent with our sequencing results. Bioinformatics analysis and target gene prediction results showed that the main biological processes and molecular functions involved in differential miRNA expression in exosomes under tensile stress were biological processes and protein binding, respectively. Kyoto Gene and Genome Data Bank (KEGG) pathway enrichment analysis showed significant enrichment of differentially expressed miRNAs in the mTOR signaling pathway. The differentially expressed miRNAs were found to target osteogenesis-related genes. Conclusion: These results suggest that stimulation of rat condylar chondrocytes with tensile stress can alter the expression levels of certain miRNAs in their exosomes and promote their osteogenic differentiation. Exosomes under tensile stress culture conditions thus have potential applications in the treatment of Osteoarthritis (OA).

The Effect of Different Frequencies of Pulsed Electromagnetic Fields on Cartilage Repair of Adipose Mesenchymal Stem Cell-Derived Exosomes in Osteoarthritis

BACKGROUND

The intra-articular injection of mesenchymal stem cell (MSC)-derived exosomes has already been proved to reverse osteoarthritic cartilage degeneration. Pulsed electromagnetic field (PEMF) has been found to regulate the biogenic function of MSCs. However, the effect of PEMF on MSC-derived exosomes has not yet been characterized. The aim of this study was to elucidate the regulatory role of different frequencies of PEMF in promoting the osteoarthritic cartilage regeneration of MSC-derived exosomes.

METHODS

The adipose tissue-derived MSCs (AMSCs) were extracted from the epididymal fat of healthy rats and further exposed to the PEMF at 1 mT amplitude and a frequency of 15, 45, and 75 Hz, respectively, in an incubator. The chondrocytes were treated with interlukin-1β (IL-1β) and the regenerative effect of co-culturing with PEMF-exposed AMSC-derived exosomes was assessed via Western blot, quantitative polymerase chain reaction, and ELISA assays. A rat model of osteoarthritis was established by anterior cruciate ligament transection (ACLT) surgery and received 4 times intra-articular injection of PEMF-exposed AMSC-derived exosomes once a week. After 8 weeks, the knee joint specimens of rats were collected for micro-computed tomography and histologic analyses.

RESULTS

PEMF-exposed AMSC-derived exosomes could be endocytosed with IL-1β-induced chondrocytes. Compared with the AMSC-derived exosomes alone, the PEMF-exposed AMSC-derived exosomes substantially suppressed the inflammation and extracellular matrix degeneration of IL-1β-induced chondrocytes as shown by higher expression of transcripts and proteins of COL2A1, SOX9, and ACAN and lower expression of MMP13 and caspase-1. Of these, the 75-Hz PEMF presented a more significant inhibitive effect than the 15-Hz and 45-Hz PEMFs. Furthermore, the intra-articular injection of 75-Hz PEMF-exposed exosomes could obviously increase the number of tibial epiphyseal trabeculae, lead to a remarkable decrease in Osteoarthritis Research Society International score, and upregulate the COL2A1 and ACAN protein level of the degenerated cartilage.

CONCLUSION

The present study demonstrated that PEMF stimulation could effectively promote the regeneration effects of AMSC-derived exosomes on osteoarthritic cartilage. Compared with other frequency parameters, the PEMF at a frequency of 75 Hz showed a superior positive effect on AMSC-derived exosomes in suppressing the IL-1β-induced chondrocyte inflammation and extracellular matrix catabolism, as well as the osteoarthritic cartilage degeneration.

MiR-199a-5p promotes ferroptosis-induced cardiomyocyte death responding to oxygen-glucose deprivation/reperfusion injury via inhibiting Akt/eNOS signaling pathway

Myocardial ischemia/reperfusion (I/R) injury is associated with the poor outcome and higher mortality after myocardial infarction. Recent studies have revealed that miR-199a-5p participates in the process of myocardial I/R injury, but the precise roles and molecular mechanisms of miR-199a-5p in myocardial I/R injury remain not well-studied. Ferroptosis has been proposed to promote cardiomyocyte death, closely associated with myocardial I/R injury. Herein, the present study aimed to explore the function and mechanisms by which miR-199a-5p regulates whether miR-199a-5p contributes to ferroptosis-induced cardiomyocyte death responding to oxygen-glucose deprivation/reoxygenation (OGD/R) injury, an in vitro model of myocardial I/R injury focusing on Akt/eNOS signaling pathway. The results found that ferroptosis-induced cardiomyocyte death occurs and is accompanied by an increase in miR-199a-5p level in OGD/R-treated H9c2 cells. MiR-199a-5p inhibitor ameliorated ferroptosis-induced cardiomyocyte death as evidenced by the increased cell viability, the reduced reactive oxygen species (ROS) generation, lactate dehydrogenase (LDH) activity, malondialdehyde (MDA) and Fe²⁺ contents, and the up-regulated glutathione (GSH)/glutathione disulphide (GSSG) ratio as well as glutathione peroxidase 4 (Gpx4) protein expression in H9c2 cells-exposed to OGD/R, while miR-199a-5p mimic had the opposite effects. In addition, OGD/R led to the inhibition of Akt/eNOS signaling pathway, which was also blocked by miR-199a-5p inhibitor and aggravated by miR-199a-5p mimic. Furthermore, LY294002, an inhibitor of Akt/eNOS signaling pathway, abrogated miR-199a-5p inhibitor-induced the reduction of ferroptosis-induced cardiomyocyte death. In summary, our findings demonstrated that miR-199a-5p plays a central role in stimulating ferroptosis-induced cardiomyocyte death during ischemic/hypoxic injury via inhibiting Akt/eNOS signaling pathway.

The protective mechanism of salidroside modulating miR-199a-5p/TNFAIP8L2 on lipopolysaccharide-induced MLE-12 cells

OBJECTIVES

Salidroside is used for treating inflammation-based diseases; however, its molecular mechanism is unclear. In this study, we determined the protective role of salidroside on the endotoxin-induced damage caused to the mouse alveolar epithelial type II (MLE-12) cells and its underlying mechanism.

METHODS

An in vitro model for acute lung injury was constructed by inducing the MLE-12 cells using lipopolysaccharide (lipopolysaccharides, 1 mg/L). Then, The MTT assay was conducted to assess the survival rate of the MLE-12 cells in the different groups. After the treatment, apoptosis of MLE-12 cells was determined, and the mRNA and protein expression of miR-199a-5p, HMGB1, NF-kB65, TNFAIP8L2, p-IkB-α, and TLR4 was estimated by Western Blotting and RT-PCR. ELISA was also used to measure the concentration of inflammatory cytokine molecules IL-1β, IL-6, TNF-α, and IL-18 in the cell-free supernatant. Lastly, cell morphology was examined using the AO/EB technique.

RESULTS

We showed that salidroside reduced the protein and gene expression of HMGB1, NF-kB65, miR-199a-5p, p-IkB-α, and TLR4, whereas it increased the gene and protein expression of TNFAIP8L2. Furthermore, it decreased the concentrations of cytokine molecules like IL-1β, IL-6, TNF-α, and IL-18 in the cell-free supernatant. MLE-12 also showed a lower apoptosis rate, higher survival rate, and better cell morphology.

CONCLUSION

Salidroside significantly inhibited the LPS-induced MLE-12 cell damage. Our results suggest that this could be by reducing miR-199a-5p and enhancing TNFAIP8L2 expression.

Synovial Fluid Regulates the Gene Expression of a Pattern of microRNA via the NF-κB Pathway: An In Vitro Study on Human Osteoarthritic Chondrocytes

Synovial fluid (SF) represents the primary source of nutrients of articular cartilage and is implicated in maintaining cartilage metabolism. We investigated the effects of SF, from patients with osteoarthritis (OA), rheumatoid arthritis (RA), and controls, on a pattern of microRNA (miRNA) in human OA chondrocytes. Cells were stimulated with 50% or 100% SF for 24 h and 48 h. Apoptosis and superoxide anion production were detected by cytometry; miRNA (34a, 146a, 155, 181a), cytokines, metalloproteinases (MMPs), type II collagen (Col2a1), antioxidant enzymes, B-cell lymphoma (BCL)2, and nuclear factor (NF)-κB by real-time PCR. The implication of the NF-κB pathway was assessed by the use of NF-κB inhibitor (BAY-11-7082). RA and OA SF up-regulated miR-34a, -146a, -155, -181a, interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, MMP-1, MMP-13, and ADAMTs-5 gene expression, while it down-regulated Col2a1. Pathological SF also induced apoptosis, reduced viability, and decreased BCL2 mRNA, whereas it increased superoxide anions, the expression of antioxidant enzymes, p65 and p50 NF-κB. Opposite and positive results were obtained with 100% control SF. Pre-incubation with BAY-11-7082 counteracted SF effects on miRNA. We highlight the role of the SF microenvironment in regulating some miRNA involved in inflammation and cartilage degradation during OA and RA, via the NF-κB pathway.

IL-17 Facilitates VCAM-1 Production and Monocyte Adhesion in Osteoarthritis Synovial Fibroblasts by Suppressing miR-5701 Synthesis

Osteoarthritis (OA) is characterized by the infiltration and adhesion of monocytes into the inflamed joint synovium. Interleukin (IL)-17 is a critical inflammatory mediator that participates in the progression of OA, although the mechanisms linking IL-17 and monocyte infiltration are not well understood. Our analysis of synovial tissue samples retrieved from the Gene Expression Omnibus (GEO) dataset exhibited higher monocyte marker (CD11b) and vascular cell adhesion molecule 1 (VCAM-1) levels in OA samples than in normal, healthy samples. The stimulation of human OA synovial fibroblasts (OASFs) with IL-17 increased VCAM-1 production and subsequently enhanced monocyte adhesion. IL-17 affected VCAM-1-dependent monocyte adhesion by reducing miR-5701 expression through the protein kinase C (PKC)-α and c-Jun N-terminal kinase (JNK) signaling cascades. Our findings improve our understanding about the effect of IL-17 on OA progression and, in particular, VCAM-1 production and monocyte adhesion, which may help with the design of more effective OA treatments.

Endothelin-1-mediated miR-let-7g-5p triggers interlukin-6 and TNF-α to cause myopathy and chronic adipose inflammation in elderly patients with diabetes mellitus

Background: Diabetes and sarcopenia are verified as mutual relationships, which seriously affect the quality of life of the elderly. Endothelin-1 is well investigated, is elevated in patients with diabetes, and is related to muscle cellular senescence and fibrosis. However, the mechanism of ET-1 between diabetes and myopathy is still unclear. The aim of this study was to evaluate the prevalence of sarcopenia in the elderly with diabetes and to clarify its relationship with ET-1 molecular biological mechanism, progress as well as changes in muscle and fat.

Methods: We recruited 157 type 2 diabetes patients over 55 years old and investigated the prevalence of sarcopenia in diabetes patients and examined the association of ET-1 alterations with HbA1c, creatinine, or AMS/ht2. Next, sought to determine how ET-1 regulates inflammation in muscle cells by western blot and qPCR assay. Using XF Seahorse Technology, we directly quantified mitochondrial bioenergetics in 3T3-L1 cells.

Results: ET-1 was positively correlated with HbA1c, creatinine levels, and duration of disease, and negatively correlated with AMS/ht2. We found that ET-1 dose-dependently induces tumor necrosis factor-α (TNF-α) and interleukin (IL)-6β expression through the PI3K/AKT, and NF-κB signaling pathways in C2C12 cells. Also identified that TNF-α, IL-6β, and visfatin releases were found in co-cultured with conditioned medium of ET-1/C2C12 in 3T3-L1 cells. ET-1 also reduces the energy metabolism of fat and induces micro-environment inflammation which causes myopathy. ET-1 also suppresses miR-let-7g-5p expression in myocytes and adipocytes.

Conclusion: We describe a new mechanism of ET-1 triggering chronic inflammation in patients with hyperglycemia.

Effect of visfatin on KATP channel upregulation in colonic smooth muscle cells in diabetic colon dysmotility

The mechanisms of diabetes-related gastrointestinal dysmotility remains unclear. This study aimed to investigate the effect and mechanisms of proinflammatory adipokine visfatin (VF) in the contractile dysfunction of diabetic rat colonic smooth muscle. Twenty Sprague-Dawley rats were randomly divided into control and type 2 diabetes mellitus groups. VF levels in the serum and colonic muscle tissues were tested, the time of the bead ejection and contractility of colonic smooth muscle strips were measured, and the expression of ATP-sensitive potassium (K_ATP) channels in the colonic muscle tissues was analyzed. In vitro, we tested VF's effects on intracellular reactive oxygen species (ROS) levels, NF-κB's nuclear transcription, K_ATP channel expression, intracellular Ca²⁺ concentrations, and myosin light chain (MLC) phosphorylation in colonic smooth muscle cells (CSMCs). The effects of NAC (ROS inhibitor) and BAY 11-7082 (NF-κB inhibitor) on K_ATP expression were also tested. Diabetic rats showed elevated VF levels in serum and colonic muscle tissues, a delayed distal colon ejection response time, weakened contractility of colonic smooth muscle strips, and increased K_ATP channel expression in colonic muscle tissues. VF significantly inhibited the contractility of colonic smooth muscle strips from normal rats. In cultured CSMCs, VF caused ROS overload, increased NF-κB nuclear transcription activity and increased expression of Kir6.1, eventually reducing intracellular Ca²⁺ levels and MLC phosphorylation. NAC and BAY 11-7082 inhibited the VF-induced Kir6.1 upregulation. In conclusion, VF may cause contractile dysfunction of CSMCs by upregulating the expression of the Kir6.1 subunit of K_ATP channels via the ROS/NF-κB pathway and interfering with Ca²⁺ signaling.

Visfatin promotes intervertebral disc degeneration by inducing IL-6 expression through the ERK/JNK/p38 signalling pathways

Visfatin reportedly induces the expression of proinflammatory cytokines. Severe grades of intervertebral disc disease (IVDD) exhibit higher expression of visfatin than mild ones. However, the direct relationship between visfatin and IVDD remains to be elucidated. This study aimed to clarify whether stimulation of visfatin in IVDD is mediated by IL-6. To investigate the role of visfatin in IVDD, a rat model of anterior disc puncture was established by injecting visfatin or PBS using a 27-gauge needle. Results revealed an obvious aggravation of the histological morphology of IVDD in the visfatin group. On treating human NP cellswith visfatin, the levels of collagenII and aggrecan decreased and those of matrix metallopeptidase 3 and IL-6 gradually increased. A rapid increase in ERK, JNK, and p38 phosphorylation was also noted after visfatin treatment. Compared to those treated with visfatin alone, NP cells pretreated with ERK1/2, JNK, and p38 inhibitors or siRNA targeting p38, ERK, and JNK exhibited a significant suppression of IL-6. Our data represent the first evidence that visfatin promotes IL-6 expression in NP cells via the JNK/ERK/p38-MAPK signalling pathways. Further, our findings suggest epidural fat and visfatin as potential therapeutic targets for controlling IVDD-associated inflammation.

Visfatin as a Promising Marker of Cardiometabolic Risk

Adipose tissue is an endocrine organ that produces molecules with important functions in the human body called adipokines. Visfatin can be secreted from various sources, such as macrophages, chondrocytes and amniotic epithelial cells other than adipose tissue. The main effect of visfatin is to promote inflammatory processes. In addition, visfatin has pivotal effects on the entire cardiovascular system, such as endothelial dysfunction, atherosclerosis, plaque rupture and mobilization, myocardial damage, fibrosis and new vessel formation. Vascular pathologies in other tissues also mediate its effects. Visfatin changes in a similar manner to cardiac markers in acute myocardial infarction, and the most cited feature in research studies is that it may be a cardiovascular risk marker. Visfatin is therefore expected to be widely used in cardiovascular pathology in the near future. Visfatin has many target tissues and various effects that occur in relatively complex biological pathways, making it difficult to understand visfatin adequately. In this review, we provide comprehensive information about this promising molecule.

Nesfatin-1 facilitates IL-1β production in osteoarthritis synovial fibroblasts by suppressing miR-204-5p synthesis through the AP-1 and NF-κB pathways

The progression of osteoarthritis (OA) is mediated by adipokines, one of which is nesfatin-1, which is responsible for the production of inflammatory cytokines. However, how this molecule may affect the synthesis of the proinflammatory cytokine interleukin 1 beta (IL-1β) in OA is unclear. Our analyses of records from the Gene Expression Omnibus (GEO) dataset and clinical specimens of synovial tissue revealed higher levels of nesfatin-1 and IL-1β in OA samples compared with normal healthy tissue. We found that nesfatin-1 facilitates IL-1β synthesis in human OA synovial fibroblasts (OASFs) and suppresses the generation of micro-RNA (miR)-204-5p, as the miR-204-5p levels in OA patients were lower than those in healthy controls. Nesfatin-1-induced stimulation of IL-1β in human OASFs occurred via the suppression of miR-204-5p synthesis by the PI3K, Akt, AP-1 and NF-κB pathways. We suggest that nesfatin-1 is worth targeting in OA treatment.

Sex and dose-dependent antinociceptive effects of the JNK (c-Jun N-terminal kinase) inhibitor SU 3327 are mediated by CB2 receptors in female, and CB1/CB2 receptors in male mice in an inflammatory pain model

Activation of c-Jun N-terminal kinases (JNKs) has been implicated in the development and persistence of inflammatory and neuropathic pain in animal models. Moreover, JNKs have been involved in the maintenance of chronic pain, as well as development of tolerance to antinociceptive agents in the opioid and cannabinoid class of compounds. In this study, we evaluated the antinociceptive effects of the JNK inhibitor SU 3327 (0.3-30 mg/kg) in the formalin pain model with an emphasis on the sex-specific actions of this compound. In wild-type C57BL6J mice, SU 3327 produced strong antinociceptive effects in the formalin pain model which were mediated by CB₂ receptors in females, and both CB₁ and CB₂ receptors in males. SU 3327 at a dose of 10 mg/kg produced antinociception, hypothermia, motor impairment, and hypolocomotion to a similar extent in both males and females. The antinociceptive effects of SU 3327 were more potent in males at lower doses (1 and 3 mg/kg), while females were more sensitive to the hypothermic, and motor-suppression effects at lower (3 mg/kg) doses versus males. Analysis of spinal cords, using qPCR following SU 3327 administration in the formalin test, revealed changes in cannabinoid, tolerance and inflammatory markers in females only, and only in the high (10-30 mg/kg) dose conditions. Indeed, females showed an increase in mRNA levels of cannabinoid (CB₂), but a decrease in tolerance (β-arrestin 1) and inflammatory (TNF-α, IL-1β, IL-6)-associated markers. The differences between males and females, in this study, support sex as an important factor in nociception and antinociceptive responses mediated by JNK and the endocannabinoid system.

Systemic versus local adipokine expression differs in a combined obesity and osteoarthritis mouse model

Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage loss and reduced joint function. OA risk factors are age and obesity. Many adipokines are altered by obesity but also OA although systemic adipokine regulation in OA is not always clear. Therefore, metabolic effects of diet-induced obesity on OA development as well as the influence of obesity and OA progression on systemic vs. local adipokine expression in joints were compared. C57Bl/6-mice fed with HFD (high fat diet) or normal diet prior to destabilization of the medial meniscus (DMM) were sacrificed 4/6/8 weeks after surgery. Sera were evaluated for adiponectin, leptin, visfatin, cytokines. Liver grading and staging for non-alcoholic steatohepatitis (NASH) was performed and crown-like structures (CLS) in adipose tissue measured. OA progression was scored histologically. Adipokine-expressing cells and types were evaluated by immunohistochemistry. Time-dependent changes in DMM-progression were reflected by increased systemic adiponectin levels in DMM especially combined with HFD. While HFD increased serum leptin, DMM reduced systemic leptin significantly. OA scores correlated with bodyweight, leptin and hepatic scoring. Locally, increased numbers of adiponectin- and leptin-producing fibroblasts were observed in damaged menisci but visfatin was not changed. Local adipokine expression was independent from systemic levels, suggesting different mechanisms of action.

miR-let-7c-5p and miR-149-5p inhibit proinflammatory cytokine production in osteoarthritis and rheumatoid arthritis synovial fibroblasts

Osteoarthritis (OA) and rheumatoid arthritis (RA) are two of the most common types of arthritis. Both are characterized by the infiltration of a number of proinflammatory cytokines into the joint microenvironment. miRNAs play critical roles in the disease processes of arthritic disorders. However, little is known about the effects of miRNAs on critical inflammatory cytokine production with OA and RA progression. Here, we found higher levels of proinflammatory cytokines including interleukin 1 beta (IL-1β), interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) in human OA and RA synovial fibroblasts (SFs) compared with normal SFs. Searches of open-source microRNA (miRNA) software determined that miR-let-7c-5p and miR-149-5p interfere with IL-1β, IL-6 and TNF-α transcription; levels of all three proinflammatory cytokines were lower in human OA and RA patients compared with normal controls. Anti-inflammatory agents dexamethasone, celecoxib and indomethacin reduced proinflammatory cytokine production by promoting the expression of miR-let-7c-5p and miR-149-5p. Similarly, ibuprofen and methotrexate also enhanced miR-let-7c-5p and miR-149-5p expression in human SFs. The evidence suggests that increasing miR-let-7c-5p and miR-149-5p expression is a novel strategy for OA and RA.

Fargesin ameliorates osteoarthritis via macrophage reprogramming by downregulating MAPK and NF-κB pathways

Background

To investigate the role and regulatory mechanisms of fargesin, one of the main components of Magnolia fargesii, in macrophage reprogramming and crosstalk across cartilage and synovium during osteoarthritis (OA) development.

Methods

Ten-week-old male C57BL/6 mice were randomized and assigned to vehicle, collagenase-induced OA (CIOA), or CIOA with intra-articular fargesin treatment groups. Articular cartilage degeneration was evaluated using the Osteoarthritis Research Society International (OARSI) score. Immunostaining and western blot analyses were conducted to detect relative protein. Raw264.7 cells were treated with LPS or IL-4 to investigate the role of polarized macrophages. ADTC5 cells were treated with IL-1β and conditioned medium was collected to investigate the crosstalk between chondrocytes and macrophages.

Results

Fargesin attenuated articular cartilage degeneration and synovitis, resulting in substantially lower Osteoarthritis Research Society International (OARSI) and synovitis scores. In particular, significantly increased M2 polarization and decreased M1 polarization in synovial macrophages were found in fargesin-treated CIOA mice compared to controls. This was accompanied by downregulation of IL-6 and IL-1β and upregulation of IL-10 in serum. Conditioned medium (CM) from M1 macrophages treated with fargesin reduced the expression of matrix metalloproteinase-13, RUNX2, and type X collagen and increased Col2a1 and SOX9 in OA chondrocytes, but fargesin alone did not affect chondrocyte catabolic processes. Moreover, fargesin exerted protective effects by suppressing p38/ERK MAPK and p65/NF-κB signaling.

Conclusions

This study showed that fargesin switched the polarized phenotypes of macrophages from M1 to M2 subtypes and prevented cartilage degeneration partially by downregulating p38/ERK MAPK and p65/NF-κB signaling. Targeting macrophage reprogramming or blocking the crosstalk between macrophages and chondrocytes in early OA may be an effective preventive strategy.

Visfatin regulates Pg LPS-induced proinflammatory/prodegradative effects in healthy and inflammatory periodontal cells partially via NF-κB pathway

Periodontitis is a widespread chronic infectious-inflammatory disease associated with multiple systemic diseases. Visfatin is an adipokine-enzyme that can be locally produced by human periodontal ligament cells (hPDLCs) and human gingival fibroblasts (hGFs). It can upregulate proinflammatory cytokines and matrix metalloproteinases (MMPs) in various types of cells. However, the effects of visfatin on healthy and inflammatory human periodontal cells as well as the underlying molecular mechanisms remain unclear. This study firstly demonstrated visfatin expression was highly elevated in inflamed human gingiva and Pg LPS-treated hPDLCs. Moreover, recombinant visfatin significantly upregulated the expression of proinflammatory cytokines (TNF-α, IL-1β and IL-6) and prodegradative factors (EMPPRIN, MMP1, MMP3 and MMP13) in hPDLCs. Next, we found the levels of proinflammatory and prodegradative cytokines were significantly increased in visfatin-overexpressing hPDLCs, and decreased in visfatin-silencing inflammatory hGFs (iGFs) when treated with Pg LPS. In the absence of Pg LPS, visfatin silencing failed to affect the expression of these factors in iGFs, and overexpression of visfatin upregulated MMPs but no other factors in hPDLCs. Furthermore, marked NF-κB pathway activation with increased phosphorylation of p65 was observed in visfatin-overexpressing hPDLCs. BAY11-7082, a specific inhibitor of NF-κB, partially reversed the upregulation proinflammatory and prodegradative factors induced by visfatin overexpression. Taken together, this study showed that visfatin critically regulates Pg LPS-induced proinflammatory/prodegradative effects in healthy and inflammatory periodontal cells partially via NF-κB pathway. The findings suggest that visfatin is closely involved in the development of periodontitis, and may serve as a promising novel biomarker and therapeutic target for periodontitis management.

Interaction between non-coding RNAs and JNK in human disorders

Jun N-terminal Kinase (JNK) signaling pathway is a conserved cascade among species with particular roles in diverse processes during embryogenesis and normal life. These kinases regulate functions of neurons and the immune system by affecting the expression of genes, modulating the arrangement of cytoskeletal proteins, and regulating apoptosis/survival pathways. They are also involved in carcinogenesis. Several miRNAs and lncRNAs have a functional relationship with JNKs. This interaction contributes to the pathogenesis of traumatic brain injury, ulcerative colitis, hepatic ischemia/ reperfusion injury, acute myocardial infarction, and a number of other disorders. Lung cancer, hepatocellular carcinoma, gall bladder cancer, melanoma, and colon cancer are among malignant conditions in which JNK-related miRNAs/ lncRNAs contribute. The current review aims at depicting the functional interaction between JNKs and lncRNAs/ miRNAs and describing the role of these regulatory transcripts in the pathobiology of human disorders.

Exploring the Crosstalk between Hydrostatic Pressure and Adipokines: An In Vitro Study on Human Osteoarthritic Chondrocytes

Obesity is a risk factor for osteoarthritis (OA) development and progression due to an altered biomechanical stress on cartilage and an increased release of inflammatory adipokines from adipose tissue. Evidence suggests an interplay between loading and adipokines in chondrocytes metabolism modulation. We investigated the role of loading, as hydrostatic pressure (HP), in regulating visfatin-induced effects in human OA chondrocytes. Chondrocytes were stimulated with visfatin (24 h) and exposed to high continuous HP (24 MPa, 3 h) in the presence of visfatin inhibitor (FK866, 4 h pre-incubation). Apoptosis and oxidative stress were detected by cytometry, B-cell lymphoma (BCL)2, metalloproteinases (MMPs), type II collagen (Col2a1), antioxidant enzymes, miRNA, cyclin D1 expressions by real-time PCR, and β-catenin protein by western blot. HP exposure or visfatin stimulus significantly induced apoptosis, superoxide anion production, and MMP-3, -13, antioxidant enzymes, and miRNA gene expression, while reducing Col2a1 and BCL2 mRNA. Both stimuli significantly reduced β-catenin protein and increased cyclin D1 gene expression. HP exposure exacerbated visfatin-induced effects, which were counteracted by FK866 pre-treatment. Our data underline the complex interplay between loading and visfatin in controlling chondrocytes' metabolism, contributing to explaining the role of obesity in OA etiopathogenesis, and confirming the importance of controlling body weight for disease treatment.

Exosomes from IL-1β-Primed Mesenchymal Stem Cells Inhibited IL-1β- and TNF-α-Mediated Inflammatory Responses in Osteoarthritic SW982 Cells

BACKGROUND

Exosomes from mesenchymal stem cells (MSCs) show anti-inflammatory effect on osteoarthritis (OA); however, their biological effect and mechanism are not yet clearly understood. This study investigated the anti-inflammatory effect and mechanism of MSC-derived exosomes (MSC-Exo) primed with IL-1β in osteoarthritic SW982 cells.

METHODS

SW982 cells were treated with interleukin (IL)-1β and tumor necrosis factor (TNF)-α to induce the OA phenotype. The effect of exosomes without priming (MSC-Exo) or with IL-1β priming (MSC-IL-Exo) was examined on the expression of pro- or anti-inflammatory factors, and the amount of IκBα was examined in SW982 cells. Exosomes were treated with RNase to remove RNA. The role of miR-147b was examined using a mimic and an inhibitor.

RESULTS

MSC-IL-Exo showed stronger inhibitory effects on the expression of pro-inflammatory cytokines (IL-1β, IL-6, and monocyte chemoattractant protein-1) than MSC-Exo. The expression of anti-inflammatory factors (SOCS3 and SOCS6) was enhanced by MSCs-IL-Exo. Priming with IL-1β increased RNA content in MSC-IL-Exo, and pretreatment with RNase abolished anti-inflammatory effect in SW982 cells. miR-147b was found in much larger amounts in MSC-IL-Exo than in MSC-Exo. The miR-147b mimic significantly inhibited the expression of inflammatory cytokines, while the miR-147b inhibitor only partially blocked the anti-inflammatory effect of MSC-IL-Exo. MSC-IL-Exo and miR-147b mimic inhibited the reduction of IκBα, an nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) inhibitor, by IL-1β and TNF-α.

CONCLUSION

This study showed that MSC exosomes with IL-1β priming exhibit significantly enhanced anti-inflammatory activity in osteoarthritic SW982 cells. The effect of IL-1β-primed MSC exosomes is mediated by miRNAs such as miR-147b and involves inhibition of the NF-κB pathway.

Handgrip strength, tumor necrosis factor-α, interlukin-6, and visfatin levels in oldest elderly patients with cognitive impairment

INTRODUCTION

Handgrip strength is associated with mild cognitive impairment. Tumor necrosis factor [TNF]-α and interleukin [IL]-6 were pro-inflammatory cytokines influencing the severity of initial neurological deficit. Visfatin is a novel adipokine and has a strong correlation with inflammation. The relationships of TNF-α, IL-6 and visfatin are not consistent, and no study has investigated them in the elderly patients with cognitive impairment.

METHODS

This study included patients aged ≥75 years at the emergency department from August 2018 to February 2019. All patients underwent comprehensive geriatric assessment and blood tests for fasting plasma TNF-α, IL-6 and visfatin levels.

RESULTS

We enrolled 106 elderly patients with a mean age of 87.3 years, including 62 (58.4%) patients in cognitive impairment group (Mini-Mental State Examination [MMSE] < 24) and 44 (41.5%) patients in the non-cognitive impairment group. Compared to the non-cognitive impairment group, the cognitive impairment group had significantly lower handgrip strength, and significantly higher TNF-α, IL-6 and visfatin levels. TNF-α positively correlated with IL-6. Both TNF-α and IL-6 negatively correlated with Barthel index and MMSE. Handgrip strength negatively correlated with TNF-α but positively correlated with Barthel index and MMSE scores. Backward and stepwise multiple logistic regression analyses showed that the independent predictor for cognitive impairment was handgrip strength and age.

CONCLUSION

The cognitive impairment group had significantly higher serum TNF-α, IL-6, and visfatin levels. The independent predictors of cognitive impairment were handgrip strength and age. Handgrip strength negatively correlated with TNF-α and IL-6 but positively with Barthel index and MMSE scores.

[Study on visfatin-induced inflammation and necroptosis via LOX-1 in human umbilical vein endothelial cells]

The aim of the study is to identify the effects and underlying mechanisms of visfatin on inflammation and necroptosis in vascular endothelial cells. Human umbilical vein endothelial cells (HUVECs) were stimulated with visfatin or pretreated with Polyinosinic acid (LOX-1 inhibitor). By using the Western blot, RT-PCR, immunocytochemistry, enzyme-linked immunosorbent assay (ELISA), MTT and flow cytometry technique, the occurrence of inflammation and necroptosis in HUVECs were evaluated. Our results showed that 100 ng/mL visfatin significantly increased the mRNA and protein expression of monocyte chemotactic protein 1 (MCP-1) and LOX-1 after 24 hours' treatment in HUVECs. However, pretreatment with Polyinosinic acid could significantly reduce the expression of MCP-1 compared with visfatin group. Additionally, 100 ng/mL visfatin could induce the production of necrotic features and increase the mRNA expression of BMF (one of the markers of necroptosis), while pretreating with Polyinosinic acid markedly downregulated the mRNA expression of BMF gene and promoted the cell proliferation. These results indicate that visfatin might induce inflammation and necroptosis via LOX-1 in HUVECs, suggesting that visfatin plays a central role in the development of atherosclerosis.

The up-regulation of markers of adipose tissue fibrosis by visfatin in pre-adipocytes as well as obese children and adolescents

Adipocytes are surrounded by a three-dimensional network of extracellular matrix (ECM) proteins. Aberrant ECM accumulation and remodeling leads to adipose tissue fibrosis. Visfatin is one of the adipocytokines that is increased in obesity and is implicated in insulin resistance. The objective of this study was to investigate the effect of visfatin on major components of ECM remodeling. In this study, plasma levels of both endotrophin and visfatin in obese children and adolescents were significantly higher than those in control subjects and they showed a positive correlation with each other. Treatment of 3T3-L1 pre-adipocytes with visfatin caused significant up-regulation of Osteopontin (Opn), Collagen type VI (Col6), matrix metalloproteinases MMP-2 and MMP-9. By using inhibitors of major signaling pathways it was shown that visfatin exerted its effect on Col6a3 gene expression through PI3K, JNK, and NF-кB pathways, while induced Opn gene expression via PI3K, JNK, MAPK/ERK, and NOTCH1. Our conclusion is that, the relationship between visfatin, endotrophin and insulin resistance parameters in obesity as well as increased expression of ECM proteins by visfatin suggests adipose tissue fibrosis as a mechanism for devastating effects of visfatin in obesity.

Visfatin increases ICAM-1 expression and monocyte adhesion in human osteoarthritis synovial fibroblasts by reducing miR-320a expression

Pathophysiological events that modulate the progression of structural changes in osteoarthritis (OA) include monocyte adhesion and infiltration, and synovial inflammation. In particular, the adhesion protein intercellular adhesion molecule type 1 (ICAM-1) promotes monocyte recruitment into the synovial tissue. Visfatin is an adipocyte hormone that promotes the release of inflammatory cytokines during OA progression. We report that visfatin enhances ICAM-1 expression in human OA synovial fibroblasts (OASFs) and facilitates the adhesion of monocytes with OASFs. AMPK and p38 inhibitors, as well as their respective siRNAs, attenuated the effects of visfatin upon ICAM-1 synthesis and monocyte adhesion. We also describe how miR-320a negatively regulates visfatin-induced promotion of ICAM-1 expression and monocyte adhesion. We detail how visfatin affects ICAM-1 expression and monocyte adhesion with OASFs by inhibiting miR-320a synthesis via the AMPK and p38 signaling pathways.

MicroRNAs in Synovial Pathology Associated With Osteoarthritis

Osteoarthritis (OA) is the most common type of arthritis, a disease that affects the entire joint. The relative involvement of each tissue, and their interactions, add to the complexity of OA, hampering our understanding of the underlying molecular mechanisms, and the generation of a disease modifying therapy. The synovium is essential in maintaining joint homeostasis, and pathologies associated with the synovium contribute to joint destruction, pain and stiffness in OA. MicroRNAs (miRNAs) are post-transcriptional regulators dysregulated in OA tissues including the synovium. MiRNAs are important contributors to OA synovial changes that have the potential to improve our understanding of OA and to act as novel therapeutic targets. The purpose of this review is to summarize and integrate current published literature investigating the roles that miRNAs play in OA-related synovial pathologies including inflammation, matrix deposition and cell proliferation.

TGF-β1 enhances FOXO3 expression in human synovial fibroblasts by inhibiting miR-92a through AMPK and p38 pathways

Osteoarthritis (OA) is an age-related disease marked by synovial inflammation and cartilage destruction arising from synovitis, joint swelling and pain. OA therapy that targets the synovium is a promising strategy for mitigating the symptoms and disease progression. Altered activity of the transforming growth factor-β1 isoform (TGF-β1) during aging underlies OA progression. Notably, aberrant forkhead box class O 3 (FOXO3) activity is implicated in the pathogenesis of various age-related diseases, including OA. This study explored the interaction and cross-talk of TGF-β1 and FOXO3 in human osteoarthritis synovial fibroblasts (OASFs). TGF-β1 stimulated FOXO3 synthesis in OASFs, which was mitigated by blocking adenosine monophosphate-activated protein kinase (AMPK) and p38 activity. TGF-β1 also inhibited the expression of miR-92a, which suppresses FOXO3 transcription. The suppression of miR-92a was effectively reversed with the blockade of the AMPK and p38 pathways. Our study showed that TGF-β1 promotes anti-inflammatory FOXO3 expression by stimulating the phosphorylation of AMPK and p38 and suppressing the downstream expression of miR-92a. These results may help to clarify OA pathogenesis and lead to better targeted treatment.

The emerging role of fibroblast-like synoviocytes-mediated synovitis in osteoarthritis: An update

Osteoarthritis (OA), the most ubiquitous degenerative disease affecting the entire joint, is characterized by cartilage degradation and synovial inflammation. Although the pathogenesis of OA remains poorly understood, synovial inflammation is known to play an important role in OA development. However, studies on OA pathophysiology have focused more on cartilage degeneration and osteophytes, rather than on the inflamed and thickened synovium. Fibroblast-like synoviocytes (FLS) produce a series of pro-inflammatory regulators, such as inflammatory cytokines, nitric oxide (NO) and prostaglandin E₂ (PGE₂ ). These regulators are positively associated with the clinical symptoms of OA, such as inflammatory pain, joint swelling and disease development. A better understanding of the inflammatory immune response in OA-FLS could provide a novel approach to comprehensive treatment strategies for OA. Here, we have summarized recently published literatures referring to epigenetic modifications, activated signalling pathways and inflammation-associated factors that are involved in OA-FLS-mediated inflammation. In addition, the current related clinical trials and future perspectives were also summarized.

NAMPT and BMAL1 Are Independently Involved in the Palmitate-Mediated Induction of Neuroinflammation in Hypothalamic Neurons

Obesity is a prominent metabolic disease that predisposes individuals to multiple comorbidities, including type 2 diabetes mellitus, cardiovascular diseases, and cancer. Elevated circulating levels of fatty acids contribute to the development of obesity, in part, by targeting the hypothalamus. Palmitate, the most abundant circulating saturated fatty acid, has been demonstrated to dysregulate NAMPT and circadian clock proteins, as well as induce neuroinflammation. These effects ultimately result in hypothalamic dysregulation of feeding behavior and energy homeostasis. NAMPT is the rate-limiting enzyme of the NAD+ salvage pathway and its expression is under the control of the circadian clock. NAD+ produced from NAMPT can modulate the circadian clock, demonstrating bidirectional interactions between circadian and metabolic pathways. Using NPY/AgRP-expressing mHypoE-46 neurons as well as the novel mHypoA-BMAL1-WT/F and mHypoA-BMAL1-KO/F cell lines, we studied whether there were any interactions between NAMPT and the core circadian clock protein BMAL1 in the palmitate-mediated induction of neuroinflammation. We report that palmitate altered Nampt, Bmal1, Per2 and the inflammatory genes Nf-κb, IκBα, Il-6, and Tlr4. Contrary to studies performed with peripheral tissues, the palmitate-mediated induction in Nampt was independent of BMAL1, and basal Nampt levels did not appear to exhibit rhythmic expression. Palmitate-induced downregulation of Bmal1 and Per2 was independent of NAMPT. However, NAMPT and BMAL1 were both involved in the regulation of Nf-κb, IκBα, Il-6, and Tlr4, as NAMPT inhibition resulted in the repression of basal Nf-κb and IκBα and normalized palmitate-mediated increases in Il-6, and Tlr4. On the other hand, BMAL1 deletion repressed basal Nf-κb, but increased basal Il-6. We conclude that NAMPT and BMAL1 do not interact at the transcriptional level in hypothalamic neurons, but are independently involved in the expression of inflammatory genes.

Visfatin Increases VEGF-dependent Angiogenesis of Endothelial Progenitor Cells during Osteoarthritis Progression

Osteoarthritis (OA) pannus contains a network of neovascularization that is formed and maintained by angiogenesis, which is promoted by vascular endothelial growth factor (VEGF). Bone marrow-derived endothelial progenitor cells (EPCs) are involved in VEGF-induced vessel formation in OA. The adipokine visfatin stimulates the release of inflammatory cytokines during OA progression. In this study, we found significantly higher visfatin and VEGF serum concentrations in patients with OA compared with healthy controls. We describe how visfatin enhanced VEGF expression in human OA synovial fibroblasts (OASFs) and facilitated EPC migration and tube formation. Treatment of OASFs with PI3K and Akt inhibitors or siRNAs attenuated the effects of visfatin on VEGF synthesis and EPC angiogenesis. We also describe how miR-485-5p negatively regulated visfatin-induced promotion of VEGF expression and EPC angiogenesis. In our OA rat model, visfatin shRNA was capable of inhibiting visfatin and rescuing EPC angiogenesis and pathologic changes. We detail how visfatin affected VEGF expression and EPC angiogenesis in OASFs by inhibiting miR-485-5p synthesis through the PI3K and Akt signaling pathways.

Apelin enhances IL-1β expression in human synovial fibroblasts by inhibiting miR-144-3p through the PI3K and ERK pathways

Much data suggests intersecting activities between the adipokine apelin (APLN) and the pathologic processes of obesity and osteoarthritis (OA), with APLN modulating cartilage, synovium, bone, and various immune cell activities. The synovium plays an important role in the pathogenesis of OA. We investigated the crosstalk between APLN, a major OA-related adipokine, and interleukin 1 beta (IL-1β), a major proinflammatory cytokine, in human OA synovial fibroblasts (OASFs). We showed that APLN stimulated the synthesis of IL-1β in a concentration- and time-dependent manner, which was mitigated by blockade of the PI3K and ERK pathway. We also showed that APLN inhibited the expression of miRNA-144-3p, which blocks IL-1β transcription; this suppression activity was reversed via blockade of the PI3K and ERK pathway. Moreover, pathologic changes in OA cartilage were rescued when APLN was silenced by shAPLN transfection both in vitro and in vivo. Our evidence is the first to show that APLN stimulates the expression of IL-1β by activating the PI3K and ERK pathway and suppressing downstream expression of miRNA-144-3p in OASFs. We also demonstrate that knockdown of APLN expression by shAPLN transfection ameliorated changes in OA cartilage severity. These results shed light on OA pathogenesis and suggest a novel treatment pathway.

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.

S1P promotes IL-6 expression in osteoblasts through the PI3K, MEK/ERK and NF-κB signaling pathways

Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disease, in which the immune system attacks joint tissue. Interleukin (IL)-6 is a key proinflammatory cytokine in RA progression. Sphingosine-1-phosphate (S1P), a platelet-derived lysophospholipid mediator, reportedly regulates osteoimmunology. Here, we examined the effects of S1P on IL-6 expression in osteoblasts. Our results and records from the Gene Expression Omnibus (GEO) database demonstrate higher levels of IL-6 in patients with RA compared with those with osteoarthritis. Stimulation of osteoblasts with S1P increased mRNA and protein expression of IL-6. PI3K, MEK, ERK and NF-κB inhibitors and their small interfering RNAs (siRNAs) reduced S1P-promoted IL-6 expression. S1P also facilitated PI3K, MEK/ERK and NF-κB signaling cascades. Our results indicate that S1P promotes the expression of IL-6 in osteoblasts via the PI3K, MEK/ERK and NF-κB signaling pathways.

Estrogen-Related Receptor γ Induces Angiogenesis and Extracellular Matrix Degradation of Temporomandibular Joint Osteoarthritis in Rats

The main causes of cartilage destruction during temporomandibular joint osteoarthritis (TMJOA) are extracellular matrix degradation and angiogenesis, accompanied by an increased level of matrix-degrading enzymes and proangiogenic factors. Interleukin 6 and extracellular signal–regulated kinase (ERK) signaling pathways may play a critical role in these two processes simultaneously, but researchers have not clearly determined the mechanism. We hypothesized that estrogen-related receptor γ (ERRγ) is involved in both cartilage degeneration and angiogenesis in TMJOA. The interactions between ERRγ and the Mmp9 and Vegfa promoter regions were investigated using a chromatin immunoprecipitation (ChIP) assay. A chick embryo chorioallantoic membrane (CAM) assay was performed to investigate the inhibitory effects of U0126 and GSK5182 on angiogenesis. Western blotting, reverse transcription–quantitative PCR (RT-qPCR), immunofluorescence staining, toluidine blue staining, and transfection with cDNAs or small interfering RNAs (siRNAs) were performed on primary mandibular condylar chondrocytes (MCCs). Unilateral anterior crossbite–induced TMJOA models were established in rats, and Western blotting, RT-qPCR, immunohistochemistry, and Safranin O-Fast Green staining were performed to evaluate changes in vivo. ERK1/2 activated matrix metalloproteinase 9 (MMP9) and vascular endothelial growth factor A (VEGFA), which are involved in cartilage destruction, through ERRγ. Based on the ChIP assay results, ERRγ directly activated the transcription of the Mmp9 and Vegfa genes. In chick embryo CAM models, U0126 and GSK5182 significantly inhibited angiogenesis. In conclusion, ERRγ is a downstream transcription factor of ERK1/2, and its upregulation leads to extracellular matrix degradation and angiogenesis in TMJOA. This study identified a common factor between inflammation and vascularization in OA as well as a new therapeutic target for OA: ERRγ.

MicroRNA Mediate Visfatin and Resistin Induction of Oxidative Stress in Human Osteoarthritic Synovial Fibroblasts Via NF-κB Pathway

Synovial membrane inflammation actively participate to structural damage during osteoarthritis (OA). Adipokines, miRNA, and oxidative stress contribute to synovitis and cartilage destruction in OA. We investigated the relationship between visfatin, resistin and miRNA in oxidative stress regulation, in human OA synovial fibroblasts. Cultured cells were treated with visfatin and resistin. After 24 h, we evaluated various pro-inflammatory cytokines, metalloproteinases (MMPs), type II collagen (Col2a1), miR-34a, miR-146a, miR-181a, antioxidant enzymes, and B-cell lymphoma (BCL)2 by qRT-PCR, apoptosis and mitochondrial superoxide production by cytometry, p50 nuclear factor (NF)-κB by immunofluorescence. Synoviocytes were transfected with miRNA inhibitors and oxidative stress evaluation after adipokines stimulus was performed. The implication of NF-κB pathway was assessed by the use of a NF-κB inhibitor (BAY-11-7082). Visfatin and resistin significantly up-regulated gene expression of interleukin (IL)-1β, IL-6, IL-17, tumor necrosis factor (TNF)-α,MMP-1, MMP-13 and reduced Col2a1. Furthermore, adipokines induced apoptosis and superoxide production, the transcriptional levels of BCL2, superoxide dismutase (SOD)-2, catalase (CAT), nuclear factor erythroid 2 like 2 (NRF2), miR-34a, miR-146a, and miR-181a. MiRNA inhibitors counteracted adipokines modulation of oxidative stress. Visfatin and resistin effects were suppressed by BAY-11-7082. Our data suggest that miRNA may represent possible mediators of oxidative stress induced by visfatin and resistin via NF-κB pathway in human OA synoviocytes.

The cross-talk between adipokines and miRNAs in health and obesity-mediated diseases

BACKGROUND

Multiple studies have revealed a direct correlation between obesity and the development of multiple comorbidities, including metabolic diseases, cardiovascular disorders, chronic inflammatory disease, and cancers. However, the molecular mechanism underlying the link between obesity and the progression of these diseases is not completely understood. Adipokines are factors that are secreted by adipocytes and play a key role in whole body homeostasis. Collaboratively, miRNAs are suggested to have key functions in the development of obesity and obesity-related disorders. Based on recently emerging evidence, obesity leads to the dysregulation of both adipokines and obesity-related miRNAs. In the present study, we described the correlations between obesity and its related diseases that are mediated by the mutual regulatory effects of adipokines and miRNAs.

METHODS

We reviewed current knowledge of the modulatory effects of adipokines on miRNAs activity and their relevant functions in pathological conditions and vice versa.

RESULTS

Our research reveals the ability of adipokines and miRNAs to control the expression and activity of the other class of molecules, and their effects on obesity-related diseases.

CONCLUSIONS

This study may help researchers develop a roadmap for future investigations and provide opportunities to develop new therapeutic and diagnostic methods for treating obesity-related diseases.

The Adipokine Network in Rheumatic Joint Diseases

Rheumatic diseases encompass a diverse group of chronic disorders that commonly affect musculoskeletal structures. Osteoarthritis (OA) and rheumatoid arthritis (RA) are the two most common, leading to considerable functional limitations and irreversible disability when patients are unsuccessfully treated. Although the specific causes of many rheumatic conditions remain unknown, it is generally accepted that immune mechanisms and/or uncontrolled inflammatory responses are involved in their etiology and symptomatology. In this regard, the bidirectional communication between neuroendocrine and immune system has been demonstrated to provide a homeostatic network that is involved in several pathological conditions. Adipokines represent a wide variety of bioactive, immune and inflammatory mediators mainly released by adipocytes that act as signal molecules in the neuroendocrine-immune interactions. Adipokines can also be synthesized by synoviocytes, osteoclasts, osteoblasts, chondrocytes and inflammatory cells in the joint microenvironment, showing potent modulatory properties on different effector cells in OA and RA pathogenesis. Effects of adiponectin, leptin, resistin and visfatin on local and systemic inflammation are broadly described. However, more recently, other adipokines, such as progranulin, chemerin, lipocalin-2, vaspin, omentin-1 and nesfatin, have been recognized to display immunomodulatory actions in rheumatic diseases. This review highlights the latest relevant findings on the role of the adipokine network in the pathophysiology of OA and RA.

MicroRNA-34a and MicroRNA-181a Mediate Visfatin-Induced Apoptosis and Oxidative Stress via NF-κB Pathway in Human Osteoarthritic Chondrocytes

Current evidence suggests a complex interaction between adipokines and microRNA (miRNA) in osteoarthritis (OA) pathogenesis. The present study explored the role of miR-34a and miR-181a in regulating apoptosis and oxidative stress induced by visfatin in human OA chondrocytes. Chondrocytes were transfected with miR-34a and miR-181a inhibitors and stimulated with visfatin for 24 h, in the presence of nuclear factor (NF)-κB inhibitor (BAY-11-7082, 2 h pre-incubation). Apoptosis and reactive oxygen species (ROS) production were detected by cytometry, miRNA, antioxidant enzymes, nuclear factor erythroid (NRF)2 and B-cell lymphoma (BCL)2 expressions by quantitative real time polymerase chain reaction (real time PCR) and western blot. P50 NF-κB subunit was measured by immunofluorescence. Visfatin significantly induced apoptosis and superoxide anion production, increased miR-34a, miR-181a, superoxide dismutase (SOD)-2, catalase (CAT), NRF2 and decreased BCL2 gene and protein expression in OA chondrocytes. All the visfatin-caused effects were suppressed by using miR-34a and miR-181a inhibitors. Pre-incubation with BAY-11-7082 counteracted visfatin-induced expression of miRNA, BCL2, SOD-2, CAT and NRF2. Inhibition of miR-34a and miR-181a significantly reduced the activation of p50 NF-κB. Visfatin confirms its ability to induce apoptosis and oxidative stress in human OA chondrocytes; these effects appeared mediated by miR-34a and miR-181a via NF-κB pathway. We highlight the relevance of visfatin as potential therapeutic target for OA treatment.

Visfatin Connection: Present and Future in Osteoarthritis and Osteoporosis

Musculoskeletal pathologies (MSPs) such as osteoarthritis (OA) and osteoporosis (OP), are a set of disorders that cause severe pain, motion difficulties, and even permanent disability. In developed countries, the current incidence of MSPs reaches about one in four adults and keeps escalating as a consequence of aging and sedentarism. Interestingly, OA and OP have been closely related to similar risk factors, including aging, metabolic alterations, and inflammation. Visfatin, an adipokine with an inflammatory and catabolic profile, has been associated with several OA and OP metabolic risk factors, such as obesity, insulin resistance, and type II diabetes. Furthermore, visfatin has been associated with the innate immune receptor toll-like receptor 4 (TLR4), which plays a key role in cartilage and bone inflammatory and catabolic responses. Moreover, visfatin has been related to several OA and OP pathologic features. The aim of this work is to bring together basic and clinical data regarding the common role of visfatin in these pathologies and their major shared risk factors. Finally, we discuss the pitfalls of visfatin as a potential biomarker and therapeutic target in both pathologies.