Hyperbaric oxygen inhibits the HMGB1/RAGE signaling pathway by upregulating Mir-107 expression in human osteoarthritic chondrocytes

Management of laryngeal chondroradionecrosis: A single-center experience

BACKGROUND

Laryngeal chondroradionecrosis (LCRN) is a rare but severe complication of radiation therapy. The study aimed to review the management of LCRN and evaluate the clinical benefit of hyperbaric oxygen therapy (HBOT).

METHODS

We retrospectively analyzed all radiation-induced LCRN patients between 2006 and 2019 at a tertiary medical center. Diagnosis was based on signs and symptoms of Chandler's classification, imaging, and/or histopathology report. The primary outcome was improvement in Chandler's grade after HBOT.

RESULTS

Of 678 irradiated laryngeal cancer patients, 29 (4.3%) were diagnosed with LCRN. The most common primary management was tracheostomy with intravenous steroids and antibiotics (59%). Ten patients received HBOT (34.5%), and six underwent total laryngectomy (21%). In HBOT-treated patients, Chandler's grade significantly improved from a median of 4 (range 2-4) to 2.5 (range 1-4; p = 0.005).

CONCLUSIONS

HBOT may benefit in the management of patients with persistence and unresponsive symptoms of LCRN following radiation therapy for laryngeal SCC.

Mechanism of KDM5A-mediated H3K4me3 modification in the osteogenic differentiation of mesenchymal stem cells in steroid-induced osteonecrosis of the femoral head

OBJECTIVES

Steroid-induced osteonecrosis of the femoral head (SONFH) is characterized by impaired osteogenesis in bone marrow mesenchymal stem cells (BMSCs). This study investigates the role of lysine-specific demethylase 5A (KDM5A) in SONFH to identify potential therapeutic targets.

METHODS

Human BMSCs were isolated and characterized for cell surface markers and differentiation capacity. A SONFH cell model was established using dexamethasone treatment. BMSCs were transfected with KDM5A overexpression vectors or si-KDM5A, and the expression of KDM5A, miR-107, runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and osteopontin (OPN) was assessed. Alizarin red staining was used to observe mineralization nodules, while alkaline phosphatase activity and cell viability were measured. The enrichment of KDM5A and histone 3 lysine 4 trimethylation (H3K4me3) on the promoters of RUNX2, OCN, and OPN was analyzed. The binding between miR-107 and KDM5A 3'UTR was validated, and the combined effect of miR-107 overexpression and KDM5A overexpression on BMSC osteogenic differentiation was evaluated.

RESULTS

KDM5A was upregulated in BMSCs from SONFH. Inhibition of KDM5A promoted osteogenic differentiation of BMSCs, associated with increased RUNX2, OCN, and OPN promoters. KDM5A bound to the promoters of RUNX2, OCN, and OPN, leading to reduced H3K4me3 levels and downregulation of their expression. Overexpression of miR-107 inhibited KDM5A and enhanced BMSC osteogenic differentiation.

CONCLUSION

KDM5A negatively regulates BMSC osteogenic differentiation by modulating H3K4me3 levels on the promoters of key osteogenic genes. miR-107 overexpression counteracts the inhibitory effect of KDM5A on osteogenic differentiation. These findings highlight the potential of targeting the KDM5A/miR-107 axis for SONFH therapy.

n-3 polyunsaturated fatty acids alleviate the progression of obesity-related osteoarthritis and protect cartilage through inhibiting the HMGB1-RAGE/TLR4 signaling pathway

Osteoarthritis (OA) is a common joint degenerative disease. There is currently no cure for OA. Dietary fatty acids have potential value in the prevention and treatment of OA. n-3 polyunsaturated fatty acids (PUFAs) have anti-inflammatory effects, but their anti-OA mechanism remains unclear. High-mobility group box 1 (HMGB1) promotes inflammation and participates the pathogenesis of OA. The purpose of this study was to investigate the protective effect of n-3 PUFAs on cartilage and whether n-3 PUFAs could exert an anti-OA effect through inhibiting HMGB1-RAGE/TLR4 signaling pathway. We established an obesity-related post-traumatic OA mice model and an in vitro study was conducted to explore the regulatory mechanism of n-3 PUFAs on HMGB1 and its signal pathway against OA. We found that diet rich in n-3 PUFAs alleviated OA-like lesions of articular cartilage with the decrease of HMGB1-RAGE/TLR4 signaling protein in mice. In SW1353 cells, DHA significantly reduced the expression of HMGB1-RAGE/TLR4 signaling protein which was up-regulated by IL-1β stimulation. HMGB1 overexpression reversed the inhibitory effect of DHA on HMGB1-RAGE/TLR4 signaling pathway. The activation of SIRT1 may participate the inhibitory effect of DHA on HMGB1-RAGE/TLR4 signaling pathway. In conclusion, n-3 PUFAs could attenuate the progression of obesity-related OA and exert protective effect on cartilage by inhibiting HMGB1-RAGE/TLR4 signaling pathway, which may be associated with the activation of SIRT1. Dietary n-3 PUFAs supplements can be considered as a potential therapeutic substance for OA.

Involvement of TLRs/NF-κB/ESE-1 signaling pathway in T-2 toxin-induced cartilage matrix degradation

T-2 toxin, a highly toxic type A monotrichothecene mycotoxin, has been found in many different types of cereals and is considered to be one of the most dangerous naturally occurring forms of food contamination. Globally, consuming grain-based food tainted with T-2 toxin poses significant risks to animal and human health. Prior research has indicated that the presence of T-2 toxin may lead to the demise of chondrocytes and the deterioration of the extracellular matrix of cartilage in degenerative bone and joint conditions, such as Kashin-Beck disease. However, the mechanisms by which T-2 toxin exerts its biological toxicity on the degradation of the extracellular matrix in cartilage are not well understood. In the current study, we found original results that demonstrate an upregulation of Toll-Like Receptors (TLR-2, TLR-4) and ESE-1 expression levels in the articular cartilage of a rat model subjected to T-2 toxin exposure. Furthermore, it was revealed that the exposure to T-2 toxin resulted in an increase in the expression of TLR-2, TLR-4, and ESE-1 in human C28/I2 chondrocytes. The findings of this study indicate that the increased expression of TLR-2, TLR-4, and ESE-1 may contribute to the development of degenerative osteoarthritic disease caused by T-2 toxin. Consistent with our hypotheses, we discovered that T-2 toxin increased the expression of MMP-1 and MMP-13 in human C28/I2 chondrocytes. We used a luciferase reporter gene assay to measure the activity of the ESE-1 promoter and transfected cells with plasmids encoding TLR-2 and TLR-4 to investigate their effects on this activity. TLR-2 and TLR-4 can activate ESE-1 transcriptional gene expression, and this expression is mediated through the NF-κB pathway, additional evidence is provided for the participation of the TLRs/NF-κB/ESE-1 signaling pathway in T-2 toxin-induced cartilage matrix degradation. Together, the findings indicated that the TLRs/NF-κB/ESE-1 signaling pathway played an essential part in T-2 toxin-induced cartilage matrix degradation.

The Role of Alarmins in Osteoarthritis Pathogenesis: HMGB1, S100B and IL-33

Osteoarthritis (OA) is a multifactorial disease in which genetics, aging, obesity, and trauma are well-known risk factors. It is the most prevalent joint disease and the largest disability problem worldwide. Recent findings have described the role of damage-associated molecular patterns (DAMPs) in the course of the disease. In particular, alarmins such as HMGB1, IL-33, and S100B, appear implicated in enhancing articular inflammation and favouring a catabolic switch in OA chondrocytes. The aims of this review are to clarify the molecular signalling of these three molecules in OA pathogenesis, to identify their possible use as staging biomarkers, and, most importantly, to find out whether they could be possible therapeutic targets. Osteoarthritic cartilage expresses increased levels of all three alarmins. HMGB1, in particular, is the most studied alarmin with increased levels in cartilage, synovium, and synovial fluid of OA patients. High levels of HMGB1 in synovial fluid of OA joints are positively correlated with radiological and clinical severity. Counteracting HMGB1 strategies have revealed improving results in articular cells from OA patients and in OA animal models. Therefore, drugs against this alarmin, such as anti-HMGB1 antibodies, could be new treatment possibilities that can modify the disease course since available medications only alleviate symptoms.

Revisiting the role of hyperbaric oxygen therapy in knee injuries: Potential benefits and mechanisms

Knee injury negatively impacts routine activities and quality of life of millions of people every year. Disruption of tendons, ligaments, and articular cartilage are major causes of knee lesions, leading to social and economic losses. Besides the attempts for an optimal recovery of knee function after surgery, the joint healing process is not always adequate given the nature of intra-articular environment. Based on that, different therapeutic methods attempt to improve healing capacity. Hyperbaric oxygen therapy (HBOT) is an innovative biophysical approach that can be used as an adjuvant treatment post-knee surgery, to potentially prevent chronic disorders that commonly follows knee injuries. Given the well-recognized role of HBOT in improving wound healing, further research is necessary to clarify the benefits of HBOT in damaged musculoskeletal tissues, especially knee disorders. Here, we review important mechanisms of action for HBOT-induced healing including the induction of angiogenesis, modulation of inflammation and extracellular matrix components, and activation of parenchyma cells-key events to restore knee function after injury. This review discusses the basic science of the healing process in knee injuries, the role of oxygen during cicatrization, and shed light on the promising actions of HBOT in treating knee disorders, such as tendon, ligament, and cartilage injuries.

Hyperbaric Oxygen Therapy and Tissue Regeneration: A Literature Survey

By addressing the mechanisms involved in transcription, signaling, stress reaction, apoptosis and cell-death, cellular structure and cell-to-cell contacts, adhesion, migration as well as inflammation; HBO upregulates processes involved in repair while mechanisms perpetuating tissue damage are downregulated. Many experimental and clinical studies, respectively, cover wound healing, regeneration of neural tissue, of bone and cartilage, muscle, and cardiac tissue as well as intestinal barrier function. Following acute injury or in chronic healing problems HBO modulates proteins or molecules involved in inflammation, apoptosis, cell growth, neuro- and angiogenesis, scaffolding, perfusion, vascularization, and stem-cell mobilization, initiating repair by a variety of mechanisms, some of them based on the modulation of micro-RNAs. HBO affects the oxidative stress response via nuclear factor erythroid 2-related factor 2 (Nrf2) or c-Jun N-terminal peptide and downregulates inflammation by the modulation of high-mobility group protein B1 (HMGB-1), toll-like receptor 4 and 2 (TLR-4, TLR-2), nuclear factor kappa-B (NFκB), hypoxia-inducible factor (HIF-1α) and nitric oxide (NO•). HBO enhances stem-cell homeostasis via Wnt glycoproteins and mammalian target of rapamycin (mTOR) and improves cell repair, growth, and differentiation via the two latter but also by modulation of extracellular-signal regulated kinases (ERK) and the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) pathway. The HBO-induced downregulation of matrix metalloproteinases-2 and 9 (MMP-2/-9), rho-associated protein kinase (ROCK) and integrins improve healing by tissue remodeling. Interestingly, the action of HBO on single effector proteins or molecules may involve both up- or downregulation, respectively, depending on their initial level. This probably mirrors a generally stabilizing potential of HBO that tends to restore the physiological balance rather than enhancing or counteracting single mechanisms.

Inhibition of HMGB1 suppresses inflammation and catabolism in temporomandibular joint osteoarthritis <em>via</em> NF-κB signaling pathway

HMGB1 is a highly conserved nuclear protein that is rapidly released into the extracellular environment during infection or tissue damage. In osteoarthritis, HMGB1 acts as a pro-inflammatory cytokine inducing a positive feedback loop for synovial inflammation and cartilage degradation. The aim of this study was to explore the role of HMGB1 in inflammation and catabolism of temporomandibular joint osteoarthritis (TMJOA) and whether inhibition of HMGB1 affects TMJOA. Human synovial fibroblasts were incubated with HMGB1, the expression of pro-inflammatory cytokines and catabolic mediators were measured by Western blot and ELISA. NF-κB signaling pathway involvement was studied by the NF-κB inhibitor and detected by Western blotting and immunofluorescence staining. TMJOA was induced by an injection of complete Freund’s adjuvant (CFA) into anterosuperior compartment of rat’s joint. An anti-HMGB1 antibody was used to assess the effect to HMGB1 in the synovium and cartilage of the CFA-induced TMJOA rats by hematoxylin and eosin, Safranin O, Masson trichrome staining, immunohistochemistry and immunofluorescence. HMGB1 markedly increased the production of MMP13, ADAMTS5, IL-1β and IL-6 through activating NF-κB signaling pathway in human synovial fibroblasts. In vivo, application of the HMGB1 neutralizing antibody effectively ameliorated the detrimental extent of TMJOA. Furthermore, the HMGB1 neutralizing antibody reduced the expression of NF-κB, pro-inflammatory cytokines and catabolic mediators in the synovium and cartilage of CFA-induced TMJOA rats. HMGB1 inhibition alleviates TMJOA by reducing synovial inflammation and cartilage catabolism possibly through suppressing the NF-κB signaling pathway and may become a therapeutic method against TMJOA.

HMGB1 Promotes Lymphangiogenesis through the Activation of RAGE on M2 Macrophages in Laryngeal Squamous Cell Carcinoma

Background. Receptor for advanced glycation end products (RAGE) is implicated in tumor biology. Released high mobility group box protein 1 (HMGB1) ligand binding to RAGE receptor in tumor cells promotes tumor progression. The mechanisms of HMGB1-RAGE signaling in M2 macrophages involved in lymphangiogenesis in laryngeal carcinoma remain poorly understood. Here, we assessed the effect of HMGB1-RAGE signaling on M2 macrophages in lymphangiogenesis. Methods. HMGB1, CD163, and D2-40 in laryngeal squamous cell carcinoma (LSCC, $n=123$ ), laryngeal precursor lesions (LPLs, $n=102$ ), and vocal polyp (VP, $n=55$ ) were analyzed by immunohistochemistry. THP-1 cell-expressed RAGE gene was knocked down and then polarized to M0 macrophages and M2 macrophages. IL-23, TNF-α, TGF-β, and IL-10 were measured by ELISA; IL-1β, IL-12, IL-10, and CCL-13 were evaluated by RT-qPCR, and CD206, CD163, and RAGE were evaluated by western blot to evaluate whether classical M2 macrophages were obtained. Conditioned media from RAGE+/- M0 macrophages and RAGE+/- M2 macrophages incubated in the presence or absence of HMGB1, anti-Toll-like receptor (TLR)2, anti-TLR4 antibodies, and anti-VEGF-C antibodies were collected separately for human dermal lymphatic endothelial cells (HDLEC) for proliferation, migration, lymphangiogenesis assay, and VEGF-C concentration analysis. Results. HMGB1 and M2 macrophage densities were increased in LSCC ( $P<0.01$ ). HMGB1 and M2 macrophage densities were significantly correlated with lymphatic vessel density (LVD) in LSCC ( $P<0.01$ ). The HMGB1 overexpression and higher M2 macrophage density were involved in lymph node metastasis ( $P<0.01$ ) and poor prognosis ( $P<0.05$ ). In vitro, conditioned medium from HMGB1-stimulated RAGE+ M2 macrophages activated lymphangiogenesis by upregulating the VEGF compared to controls ( $P<0.05$ ). On the contrary, RAGE knockdown obviously decreased the corresponding effects of HMGB1-preconditioned M2 macrophages upon HDLEC ( $P<0.05$ ). HMGB1-TLR pathway does not significantly increase HDLEC proliferation, migration, and lymphangiogenesis on M2 macrophages. Conclusions. HMGB1 promotes lymphangiogenesis by activation of RAGE on M2 macrophages. Targeting RAGE may provide an effective therapeutic strategy against M2 macrophages in LSCC patients with lymph node metastasis.

A review of non-coding RNA related to NF-κB signaling pathway in the pathogenesis of osteoarthritis

Osteoarthritis (OA), often called as "wear and tear" arthritis, is the most common form of degenerative joint arthritis and is a leading cause of disability. The nuclear factor-kappaB (NF-κB) transcription factor has long been recognized as a disease-contributing factor for OA. More and more evidences show that targeting NF-κB signaling could offer novel potential therapeutic options for OA damage and reduce the risk of potential side-effects. In recent years, it has been shown that non-coding RNAs(ncRNAs) can trigger the expression of an array of genes and widely activate NF-κB signaling pathway, which induces destruction of the articular joint, leading to OA onset and progression. In this review, we discuss the involvement of NF-κB in OA pathogenesis and how ncRNAs attend and affect OA incidence and evolution, offering novel potential therapeutic options for OA treatment.

Recent Advances in Pharmacological Intervention of Osteoarthritis: A Biological Aspect

Osteoarthritis (OA) is a degenerative joint disease in the musculoskeletal system with a relatively high incidence and disability rate in the elderly. It is characterized by the degradation of articular cartilage, inflammation of the synovial membrane, and abnormal structure in the periarticular and subchondral bones. Although progress has been made in uncovering the molecular mechanism, the etiology of OA is still complicated and unclear. Nevertheless, there is no treatment method that can effectively prevent or reverse the deterioration of cartilage and bone structure. In recent years, in the field of pharmacology, research focus has shifted to disease prevention and early treatment rather than disease modification in OA. Biologic agents become more and more attractive as their direct or indirect intervention effects on the initiation or development of OA. In this review, we will discuss a wide spectrum of biologic agents ranging from DNA, noncoding RNA, exosome, platelet-rich plasma (PRP), to protein. We searched for key words such as OA, DNA, gene, RNA, exosome, PRP, protein, and so on. From the pharmacological aspect, stem cell therapy is a very special technique, which is not included in this review. The literatures ranging from January 2016 to August 2021 were included and summarized. In this review, we aim to help readers have a complete and precise understanding of the current pharmacological research progress in the intervention of OA from the biological aspect and provide an indication for the future translational studies.

Exosomal microRNA-107 reverses chemotherapeutic drug resistance of gastric cancer cells through HMGA2/mTOR/P-gp pathway

Background

RNA cargo in exosomes, especially microRNAs (miRNAs), play an important role in the chemotherapy drug resistance of human cancers. However, the role and mechanism of exosomal miR-107 on multidrug resistance of gastric cancer cells was still not clear. In this study, we sought to explore whether exosomal miR-107 could reverse the resistance of gastric cancer cells to the chemotherapy drugs.

Methods

We extracted exosomes from sensitive (SGC-7901, MGC-803) and resistant (SGC-7901/5-FU) gastric cancer cells by ultracentrifugation and the isolated exosomes were identified using transmission electron microscopy (TEM) and dynamic light scattering analysis (DLS). The expression of miR-107 and high mobility group A2 (HMGA2) were detected by real-time quantitative PCR (RT-qPCR). MTT assay was used to investigate the effect of exosomes on gastric cancer cells growth in vitro. The uptake of exosomes by recipient cells were observed using a fluorescence microscope. The predicted target relationship between miR-107 and HMGA2 was verified by gauss-luciferase reporter assay. The expression of HMGA2, p-mTOR/mTOR, P-gp and other exosomal indicated marker proteins was detected by western blot.

Results

Our results indicated that the isolated exosomes were typically cup-like lipid bilayer membranes structure. SGC-7901/5-FU cells were cross-resistant to chemotherapy drug cisplatin (CDDP), and the sensitive cells-secreted exosomes drastically reversed the resistance of the resistant GC cells to the chemotherapeutic drugs, which was verified by exosomal inhibitor GW4896. Mechanistically, the reversal effect was mainly mediated by exosome-secreted miR-107 through downregulating the expression of target molecular HMGA2 and inhibiting HMGA2/mTOR/P-gp pathway, which were supported by results from luciferase reporter assay and rescue assay.

Conclusions

These findings demonstrated that exosome-transmitted miR-107 significantly enhanced the sensitivity of resistant gastric cancer cells to chemotherapeutic agents by mediating the HMGA2/mTOR/P-gp axis and exosomal miR-107 may be a novel target in gastric cancers treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09020-y.

[Mechanism of high expression of high mobility group protein 1 in a rat model of knee osteoarthritis]

OBJECTIVE

To investigate the molecular mechanism triggering pyroptosis of synovial fibroblast-like synoviocytes(FLSs)and the release of high mobility group protein 1(HMGB1)in a rat model of knee osteoarthritis(KOA).

METHODS

Twelve SD rats were randomized equally into blank control group without any treatment and KOA group with anterior cruciate ligament amputation (ACLT) to induce KOA.HE staining and Mankin score were used to evaluate the damage of knee cartilage.Western blotting was used to detect the expression of pyroptosis-related proteins and HMGB1 in the synovial tissue.In the cell experiment, rat FLSs were treated with PBS (control group), LPS+ATP (to induce cell pyroptosis), or LPS+ATP+siRNAs (to inhibit pyroptosis of the FLSs), and the cellular expressions of apoptosis-related proteins and HMGB1 were detected using Western blotting; the level of HMGB1 in the culture supernatant was detected with ELISA.

RESULTS

In the rat models of KOA, the expressions of pyroptosis-related proteins and HMGB1 in the synovial tissue and Mankin score were significantly increased as compared with those in the control group(P < 0.05).In cultured rat FLSs, the expressions of apoptosis related proteins and HMGB1 were significantly higher in the pyroptosis group than in the control group and in cells transfected with the siRNAs targeting NLRP1, NLRP3, ASC and caspase-1(P < 0.05).The protein level of HMGB1 in the culture supernatant was significantly higher in pyroptosis group than in the control and siRNA groups (P < 0.05).

CONCLUSION

In the pathological process of KOA, NLRPs inflammasome-mediated FLS pyroptosis causes massive release of HMGB1, which is associated with the activation of the downstream molecule caspase-1.

Downregulation of high mobility group box 1 enhances the radiosensitivity of non-small cell lung cancer by acting as a crucial target of microRNA-107

High mobility group box 1 (HMGB1) has been reported to regulate the sensitivity of several types of cancer cell to chemoradiotherapy. The present study aimed to investigate the changes in HMGB1 expression after radiotherapy, as well as its regulatory role in the radiosensitivity of non-small cell lung cancer (NSCLC) cells. The expression levels of HMGB1 in the serum of 73 patients with NSCLC were analyzed by ELISA. HMGB1 mRNA and microRNA (miR)-107 expression in NSCLC cells were assessed using reverse transcription-quantitative PCR. Receiver operating characteristic analysis was used to evaluate the diagnostic value of HMGB1. Cell counting kit-8, Transwell invasion and clonogenic assays were used to determine cellular viability, invasiveness and colony formation ability, respectively. Following radiotherapy, the levels of HMGB1 were significantly decreased in the serum of patients with NSCLC, and lower serum levels had relatively high diagnostic accuracy in radiosensitive patients. Furthermore, HMGB1-knockdown retarded cellular proliferation and invasion with or without irradiation, and enhanced NSCLC cell radiosensitivity. Furthermore, knocking down miR-107 reversed the decreases in cellular proliferation and invasiveness both with and without irradiation, and reduced the survival fractions induced by sh-HMGB1. HMGB1-knockdown leads to radiosensitivity that may result from suppression of the Toll-like receptor 4 (TLR4)/NF-κB signaling pathway. Collectively, decreased expression of HMGB1 was found to be a putative diagnostic predictor of radiosensitivity in patients with NSCLC. HMGB1-knockdown inhibited the proliferation and enhanced the radiosensitivity of NSCLC cells, which may be regulated via miR-107 by mediating the TLR4/NF-κB signaling pathway. Thus, HMGB1 may be a potential regulator of radioresistance in NSCLC, and the HMGB1/miR-107 axis may represent a promising therapeutic target.

miR-107 affects cartilage matrix degradation in the pathogenesis of knee osteoarthritis by regulating caspase-1

Background

Knee osteoarthritis (KOA) seriously affects the quality of life of KOA patients. This study aimed to investigate whether miR-107 could regulate KOA through pyroptosis to affect collagen protein secreted by chondrocytes through IL-1β.

Methods

The proliferation of chondrocytes was detected by CCK-8 assay. RT-qPCR analysis was used to identify miR-107 expression and transfection effects. The expression of Col II, IL-1β, IL-18, and MMP13 in supernatant of chondrocytes or chondrocytes was detected by ELISA assay and western blot analysis. The pyroptosis of chondrocytes was analyzed by TUNEL assay and the expression of pyroptosis-related proteins was analyzed by western blot. Luciferase reporter assay confirmed the relation of miR-107 to caspase-1.

Results

The proliferation of chondrocytes was decreased after LPS induction and further decreased by treatment of ATP. Single LPS treatment for chondrocytes downregulated the Col II expression while upregulated the expression of IL-1β, IL-18, and MMP-13, which was further changed by ATP treatment. miR-107 expression was decreased in chondrocytes induced by LPS and further decreased in chondrocytes induced by LPS and ATP. In addition, miR-107 overexpression increased the proliferation and decreased the pyroptosis of chondrocytes induced by LPS and ATP. miR-107 overexpression upregulated the Col II expression while down-regulated the expression of IL-1β, IL-18, and MMP-13 in supernatant of chondrocytes or chondrocytes induced by LPS and ATP. miR-107 overexpression down-regulated the expression of caspase-1, c-caspase-1, GSDMD-N, and TLR4 in chondrocytes induced by LPS and ATP. Furthermore, miR-107 directly targeted caspase-1.

Conclusions

miR-107 can protect against KOA by downregulating caspase-1 to decrease pyroptosis, thereby promoting collagen protein secreted by chondrocytes by down-regulating IL-1β.

MiR-129-5p shuttled by human synovial mesenchymal stem cell-derived exosomes relieves IL-1β induced osteoarthritis via targeting HMGB1

AIMS

To explore the therapeutic effect of miR-129-5p carried by exosomes from Human Synovial Mesenchymal Stem Cell (HS-MSC) on osteoarthritis(OA).

MATERIALS AND METHODS

The levels of miR-129-5p and high mobility group protein -1 (HMGB1) and interleukin-1β (IL-1β) in the joint fluid of OA patients were respectively detected via real-time quantitative reverse transcription-PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). IL-1β was taken to act on chondrocytes for the establishment of OA model in vitro. Ultracentrifugation was conducted to isolate HS-MSC exosomes (HS-MSC-Exo) from the supernatant. Western blot and ELISA were carried out to measure the expression of iNOS, COX2, MMP13, Collagen 2, TLR4, NF-κB, Caspase3, Bcl-2, HMGB1 in chondrocytes. Flow cytometry was conducted to detect the apoptosis of chondrocytes. Besides, bioinformatics was employed to predict the targeted relationship between miR-129-5p and HMGB1, which was further verified via dual luciferase activity experiments.

KEY FINDINGS

The results illustrated that miR-129-5p was decreased in OA patients and IL-1β-induced chondrocytes, while HMGB1 was notably upregulated. HS-MSC-Exo rich in miR-129-5p remarkably declined the inflammatory response and apoptosis of chondrocytes, while HS-MSC-Exo deficient in miR-129-5p increased the IL-1β-mediated inflammatory response and apoptosis of chondrocytes. In terms of mechanism, miR-129-5p targets the 3'UTR end of HMGB1 and inhibits IL-1β-mediated upregulation of HMGB1.

SIGNIFICANCE

In a word, this paper proved that miR-129-5p, existing in HS-MSC-Exo, can suppress the IL-1β-mediated OA by inhibiting HMGB1 release.

Relationship between the pyroptosis of fibroblast‑like synoviocytes and HMGB1 secretion in knee osteoarthritis

High mobility group box 1 (HMGB1) is an important downstream product of pyroptosis in macrophages, and it serves a vital role in numerous inflammatory diseases. Previous studies have reported that HMGB1 is released by fibroblast-like synoviocytes (FLSs) that are activated by inflammatory cytokines in knee osteoarthritis (KOA); however, the mechanism via which FLS promotes HMGB1 secretion in KOA remains unknown. According to our previous study, pyroptosis occurs in FLSs of patients with KOA and is mediated by Nod-like receptor protein (NLRP)1 or NLRP3 inflammasomes. However, the specific relationship between HMGB1 secretion and FLS pyroptosis requires further investigation. In the present study, the association between HMGB1 secretion and FLS pyroptosis was investigated in vitro and in vivo. In this study, western blotting, ELISA and reverse transcription-quantitative PCR were used to measure expression levels of proteins and mRNA. Caspase-1 activity assay and Hoechst 33342/PI double staining were used to observe the pyroptosis of FLSs. Hematoxylin and eosin staining was used to observe the destruction of cartilage in KOA. Increased expression levels of pyroptosis-related proteins and HMGB1 in the synovium of rat anterior cruciate ligament transection-induced KOA models were identified, and these changes were significantly mitigated via the intra-articular injection of a caspase-1 inhibitor. In vitro, FLSs were treated with lipopolysaccharide (LPS) + ATP to induce pyroptosis, and HMGB1 secretion was subsequently measured. LPS + ATP significantly increased the expression levels of pyroptosis-related proteins and HMGB1 in FLSs, and these effects were significantly mitigated by small interfering RNAs targeting NLRP1, NLRP3, apoptosis-associated speck-like protein with a caspase-recruitment domain or caspase-1. Therefore, the present results indicated that NLRP1/NLRP3 inflammasome-mediated and caspase-1-dependent FLS pyroptosis increased HMGB1 secretion in KOA. These findings may provide a therapeutic strategy to decrease synovial inflammatory responses during KOA progression.

Neutrophil Extracellular Traps (NETs) and Damage-Associated Molecular Patterns (DAMPs): Two Potential Targets for COVID-19 Treatment

COVID-19 is a pandemic disease caused by the new coronavirus SARS-CoV-2 that mostly affects the respiratory system. The consequent inflammation is not able to clear viruses. The persistent excessive inflammatory response can build up a clinical picture that is very difficult to manage and potentially fatal. Modulating the immune response plays a key role in fighting the disease. One of the main defence systems is the activation of neutrophils that release neutrophil extracellular traps (NETs) under the stimulus of autophagy. Various molecules can induce NETosis and autophagy; some potent activators are damage-associated molecular patterns (DAMPs) and, in particular, the high-mobility group box 1 (HMGB1). This molecule is released by damaged lung cells and can induce a robust innate immunity response. The increase in HMGB1 and NETosis could lead to sustained inflammation due to SARS-CoV-2 infection. Therefore, blocking these molecules might be useful in COVID-19 treatment and should be further studied in the context of targeted therapy.

Role of MicroRNA, LncRNA, and Exosomes in the Progression of Osteoarthritis: A Review of Recent Literature

Osteoarthritis (OA) is a common clinical degenerative disease characterized by the destruction of articular cartilage, which has an increasing impact on people's lives and social economy. The pathogenesis of OA is complex and unclear, and there is no effective way to block its progress. The study of the pathogenesis of OA is the prerequisite for the early diagnosis and effective treatment of OA. To define the pathogenesis of OA, this review considers the pathological mechanism of OA that involves microRNA, lncRNA, and exosomes. More and more evidence shows that microRNA, lncRNA, and exosomes are closely related to OA. MicroRNA inhibits the target gene by binding to the 3'- untranslated region of the targets. LncRNA usually competes with microRNA to regulate the expression level of downstream genes, while exosomes, as a carrier of intercellular information transfer, transmit the biological information of mother cells to target cells, and the effect of exosomes secreted by different cells on OA are different. In this review, we emphasized that different microRNA, lncRNA, and exosomes have different regulatory effects on chondrocyte proliferation and apoptosis, extracellular matrix degradation and inflammation. Besides, we classified and analyzed these molecules according to their effects on the progress of OA. Based on the analysis of the reported literature, this review reveals some pathogenesis of OA, and emphasizes that microRNA, lncRNA, and exosomes have great potential to assist early diagnosis and effective treatment of OA.

Scaffold-Based Gene Therapeutics for Osteochondral Tissue Engineering

Significant progress in osteochondral tissue engineering has been made for biomaterials designed to deliver growth factors that promote tissue regeneration. However, due to diffusion characteristics of hydrogels, the accurate delivery of signaling molecules remains a challenge. In comparison to the direct delivery of growth factors, gene therapy can overcome these challenges by allowing the simultaneous delivery of growth factors and transcription factors, thereby enhancing the multifactorial processes of tissue formation. Scaffold-based gene therapy provides a promising approach for tissue engineering through transfecting cells to enhance the sustained expression of the protein of interest or through silencing target genes associated with bone and joint disease. Reports of the efficacy of gene therapy to regenerate bone/cartilage tissue regeneration are widespread, but reviews on osteochondral tissue engineering using scaffold-based gene therapy are sparse. Herein, we review the recent advances in gene therapy with a focus on tissue engineering scaffolds for osteochondral regeneration.