Salidroside Alleviates Cartilage Degeneration Through NF-κB Pathway in Osteoarthritis Rats

Natural products in osteoarthritis treatment: bridging basic research to clinical applications

Osteoarthritis (OA) is the most prevalent degenerative musculoskeletal disease, severely impacting the function of patients and potentially leading to disability, especially among the elderly population. Natural products (NPs), obtained from components or metabolites of plants, animals, microorganisms etc., have gained significant attention as important conservative treatments for various diseases. Recently, NPs have been well studied in preclinical and clinical researches, showing promising potential in the treatment of OA. In this review, we summed up the main signaling pathways affected by NPs in OA treatment, including NF-κB, MAPKs, PI3K/AKT, SIRT1, and other pathways, which are related to inflammation, anabolism and catabolism, and cell death. In addition, we described the therapeutic effects of NPs in different OA animal models and the current clinical studies in OA patients. At last, we discussed the potential research directions including in-depth analysis of the mechanisms and new application strategies of NPs for the OA treatment, so as to promote the basic research and clinical transformation in the future. We hope that this review may allow us to get a better understanding about the potential bioeffects and mechanisms of NPs in OA therapy, and ultimately improve the effectiveness of NPs-based clinical conservative treatment for OA patients.

Salidroside suppresses cell growth and inflammatory response of fibroblast-like synoviocytes via inhibition of phosphoinositol-3 kinase/threonine kinase signaling in rheumatoid arthritis

BACKGROUND

Salidroside (Sal) is a natural product commonly isolated from Rhodiola rosea L., which has been found to have numerous pharmacological activities (e.g., ameliorating apoptosis and inflammation, and acting as an antioxidant) in various diseases, but its concrete function in rheumatoid arthritis (RA) has not been revealed yet. Here, we aimed to explore the specific role and underlying mechanisms of Sal in RA-fibroblast-like synoviocytes (RA-FLSs).

METHODS

Cell counting kit 8 (CCK-8) was used to assess the viability of normal-FLSs and RA-FLSs. Cell apoptosis in RA-FLSs was evaluated by flow cytometry. Western blotting was prepared to examine the levels of apoptosis- and signaling-related proteins. Wound-healing and Transwell assays were conducted to examine RA-FLSs migration and invasion. Enzyme-linked immunosorbent assay (ELISA) was used to assess the effect of Sal on tumor necrosis factor-alpha (TNF-α)-induced inflammation in RA-FLSs. RA animal model was established through complete Freund's adjuvant (CFA) induction, and the histopathological changes in synovial tissues of the rat model were analyzed by H&E staining.

RESULTS

RA-FLSs were treated with 200 μM Sal for 24 h, and cell viability was significantly suppressed. Sal promoted RA-FLSs apoptosis. The migratory and invasive abilities of RA-FLSs were markedly inhibited by Sal. Sal incubation reduced the levels of inflammatory cytokines interleukin‑8 (IL-8), IL-1β, and IL‑6 in RA-FLSs under the stimulation of TNF‑α. Subsequently, Sal downregulated phosphorylated phosphatidylinositol‑3 kinase (p-PI3K) and protein kinase (p-AKT) expression in RA-FLSs. After the treatment with pathway activator 740Y‑P (20 μM) in RA-FLSs, the promotive effect of Sal on cell apoptosis was reversed, and inhibitory effects of it on cell viability, migration, invasion, and inflammatory response were abolished. Sal inhibited RA development in the CFA-induced rat model.

CONCLUSION

Sal suppressed cell growth and inflammation in RA-FLSs by inactivating PI3K/AKT-signaling pathways.

IL-17 in osteoarthritis: A narrative review

Osteoarthritis (OA) is a painful joint disease that is common among the middle-aged and elderly populations, with an increasing prevalence. Therapeutic options for OA are limited, and the pathogenic mechanism of OA remains unclear. The roles of cytokines and signaling pathways in the development of OA is a current research hot spot. Interleukin (IL)-17 is a pleiotropic inflammatory cytokine produced mainly by T helper 17 cells that has established roles in host defense, tissue repair, lymphoid tissue metabolism, tumor progression, and pathological processes of immune diseases, and studies in recent years have identified an important role for IL-17 in the progression of OA. This narrative review focuses on the mechanisms by which IL-17 contributes to articular cartilage degeneration and synovial inflammation in OA and discusses how IL-17 and the IL-17 signaling pathway affect the pathological process of OA. Additionally, therapeutic targets that have been proposed in recent years based on IL-17 and its pathway in OA are summarized as well as recent advances in the study of IL-17 pathway inhibitors and the potential challenges of their use for OA treatment.

Albiflorin alleviation efficacy in osteoarthritis injury using in-vivo and in-vitro models

OBJECTIVES

Osteoarthritis seriously affects the daily life of people. Albiflorin (AF) has anti-inflammatory and antioxidant functions in various human diseases. This study aimed to clarify the function and mechanism of AF in osteoarthritis.

METHODS

The functions of AF on rat chondrocyte proliferation and apoptosis, inflammatory response, oxidative stress and extracellular matrix (ECM) degradation in rat chondrocytes induced by interleukin-1beta (IL-1β) were evaluated by Western blot, immunofluorescence, flow cytometry and enzyme-linked immunosorbent assay. The mechanism of AF on the IL-1β induced rat chondrocyte injury was investigated by multiple experiments in vitro. Meanwhile, the AF function in vivo was assessed using haematoxylin-eosin staining, Alcian blue, Safranin O/Fast green staining, immunohistochemical analysis and TUNEL assay.

KEY FINDINGS

Functionally, AF accelerated the rat chondrocyte proliferation and repressed cell apoptosis. Meanwhile, AF reduced the inflammatory response, oxidative stress and ECM degradation in rat chondrocytes caused by IL-1β. Mechanistically, the receptor activator of the NF-kappaB ligand (RANKL), an activator for the NF-κB signalling pathway, partially reversed the alleviating effect of AF on IL-1β-induced chondrocyte injury. Furthermore, the in-vitro results confirmed that AF exerted protective properties against osteoarthritis injury in vivo.

CONCLUSION

Albiflorin relieved osteoarthritis injury in rats by inactivating the NF-κB pathway.

Natural anti-inflammatory products for osteoarthritis: From molecular mechanism to drug delivery systems and clinical trials

Osteoarthritis (OA) is a degenerative joint disease that affects millions globally. The present nonsteroidal anti-inflammatory drug treatments have different side effects, leading researchers to focus on natural anti-inflammatory products (NAIPs). To review the effectiveness and mechanisms of NAIPs in the cellular microenvironment, examining their impact on OA cell phenotype and organelles levels. Additionally, we summarize relevant research on drug delivery systems and clinical randomized controlled trials (RCTs), to promote clinical studies and explore natural product delivery options. English-language articles were searched on PubMed using the search terms "natural products," "OA," and so forth. We categorized search results based on PubChem and excluded "natural products" which are mix of ingredients or compounds without the structure message. Then further review was separately conducted for molecular mechanisms, drug delivery systems, and RCTs later. At present, it cannot be considered that NAIPs can thoroughly prevent or cure OA. Further high-quality studies on the anti-inflammatory mechanism and drug delivery systems of NAIPs are needed, to determine the appropriate drug types and regimens for clinical application, and to explore the combined effects of different NAIPs to prevent and treat OA.

Salidroside attenuates HALI via IL-17A-mediated ferroptosis of alveolar epithelial cells by regulating Act1-TRAF6-p38 MAPK pathway

BACKGROUND AND PURPOSE

Hyperoxia-induced acute lung injury (HALI) is a critical life-threatening disorder characterized by severe infiltration immune cells and death of type II alveolar epithelial cells (AECII). However, little is known about the relations between immune cells and AECII in HALI. IL-17A is a pro-inflammatory cytokine mainly secreted by Th17 cells, contributing to the pathogenesis of various inflammatory diseases. The present study investigated the role of IL-17A in cell-cell communication between immune cells and AECII in HALI, and explored the therapeutic effect of salidroside (Sal, a natural anti-inflammatory agents) on HALI.

METHODS

Mice with HALI were induced by exposure to hyperoxia over 90% for 12 h, 24 h, 48 h or 72 h, and the optimal timing was detected by H&E and Masson staining. Ferroptosis was confirmed by detecting the levels of MDA, Fe²⁺ and GPX4, and the morphological alterations of AECII under transmission electron microscopy. The expression of pro-inflammatory cytokine, including IL-6, TGF-β1, IL-17A and IL-17A receptor (IL-17RA) were measured by Western blotting and immunohistochemical stanning. The ferroptosis-related Act1/TRAF6/p38 MAPK pathway was detected by Western blotting. The role of pro-inflammatory cytokine IL-17A for AECII ferroptosis, and the effect of Sal on HALI were investigated by administration of Y-320 (IL-17 inhibitor) and Sal respectively 3 days before mice exposed to hyperoxia.

RESULTS

Mice exposed to hyperoxia for 24 h suffered sufficient HALI with inflammatory cell infiltration and collagen deposition, and exhibited features of ferroptosis under TME. Meanwhile, compared with sham mice, mice exposed to hyperoxia showed down-regulation of GPX4, and up-regulation of IL-6, TGF-β1, IL-17A, IL-17RA, Act1, TRAF6, p38 MAPK and p-p38 MAPK. Moreover, inhibition of IL-17A with Y-320 or administration with Sal could reverse the effect caused by hyperoxia respectively.

CONCLUSIONS

IL-17A is associated with immune cells infiltration in HALI, and contributes to ferroptosis of AECII that related to Act1/TRAF6/p38 MAPK pathway. Additionally, Sal protects against HALI throughout the whole pathogenic process. Video Abstract.

Tibetan medicine salidroside improves host anti-mycobacterial response by boosting inflammatory cytokine production in zebrafish

The treatment for tuberculosis (TB), especially multidrug-resistant TB (MDR-TB), has a prolonged cycle which can last up to a year. This is partially due to the lack of effective therapies. The development of novel anti-TB drugs from the perspective of host immune regulation can provide an important supplement for conventional treatment strategies. Salidroside (SAL), a bioactive component from the Tibetan medicine Rhodiola rosea, has been used in the treatment of TB, although its mechanism remains unclear. Here, the bacteriostatic effect of SAL in vivo was first demonstrated using a zebrafish–M. marinum infection model. To further investigate the underlying mechanism, we then examined the impact of SAL on immune cell recruitment during wound and infection. Increased macrophage and neutrophil infiltrations were found both in the vicinity of the wound and infection sites after SAL treatment compared with control, which might be due to the elevated chemokine expression levels after SAL treatment. SAL treatment alone was also demonstrated to improve the survival of infected zebrafish larvae, an effect that was amplified when combining SAL treatment with isoniazid or rifampicin. Interestingly, the reduced bacterial burden and improved survival rate under SAL treatment were compromised in tnfα-deficient embryos which suggests a requirement of Tnfα signaling on the anti-mycobacterial effects of SAL. In summary, this study provides not only the cellular and molecular mechanisms for the host anti-mycobacterial effects of the Tibetan medicine SAL but also proof of concept that combined application of SAL with traditional first-line anti-TB drugs could be a novel strategy to improve treatment efficacy.

Salidroside alleviates hepatic ischemia-reperfusion injury during liver transplant in rat through regulating TLR-4/NF-κB/NLRP3 inflammatory pathway

Salidroside has anti-inflammatory, antioxidant and hepatoprotective properties. However, its effect on hepatic ischemia–reperfusion injury (IRI), an unavoidable side effect associated with liver transplantation, remains undefined. Here, we aimed to determine whether salidroside alleviates hepatic IRI and elucidate its potential mechanisms. We used both in vivo and in vitro assays to assess the effect and mechanisms of salidroside on hepatic IRI. Hepatic IRI rat models were pretreated with salidroside (5, 10 or 20 mg/kg/day) for 7 days following liver transplantation while hypoxia/reoxygenation (H/R) model of RAW 264.7 macrophages were pretreated with salidroside (1, 10 or 50 μM). The effect of salidroside on hepatic IRI was assessed using hematoxylin–eosin staining, terminal deoxynucleotidyl transferase dUTP nick-end labeling staining, qRT-PCR, immunosorbent assay and western blotting. Our in vivo assays showed that salidroside significantly reduced pathological liver damage, serum aminotransferase levels and serum levels of IL-1, IL-18 and TNF-α. Besides, salidroside reduced the expression of TLR-4/NF-κB/NLRP3 inflammatory pathway associated proteins (TLR-4, MyD88, p-IKKα, p-IKKβ, p-IKK, p-IκBα, p-P65, NLRP3, ASC, Cleaved caspase-1, IL-1β, IL-18, TNF-α and IL-6) in rats after liver transplantation. On the other hand, data from the in vitro analysis demonstrated that salidroside blocks expression of TLR-4/NF-κB/NLRP3 inflammatory pathway related proteins in the RAW264.7 cells treated with H/R. The salidroside-specific anti-inflammatory effects were partially inhibited by the TLR-4 agonist lipopolysaccharide. Taken together, our study showed that salidroside inhibits hepatic IRI following liver transplantation by modulating the TLR-4/NF-κB/NLRP3 inflammatory pathway.

Antiviral Role of Phenolic Compounds against Dengue Virus: A Review

Phenolic compounds have been related to multiple biological activities, and the antiviral effect of these compounds has been demonstrated in several viral models of public health concern. In this review, we show the antiviral role of phenolic compounds against dengue virus (DENV), the most widespread arbovirus globally that, after its re-emergence, has caused multiple epidemic outbreaks, especially in the last two years. Twenty phenolic compounds with anti-DENV activity are discussed, including the multiple mechanisms of action, such as those directed against viral particles or viral proteins, host proteins or pathways related to the productive replication viral cycle and the spread of the infection.

Small molecule compounds promote the proliferation of chondrocytes and chondrogenic differentiation of stem cells in cartilage tissue engineering

The application of tissue engineering to generate cartilage is limited because of low proliferative ability and unstable phenotype of chondrocytes. The sources of cartilage seed cells are mainly chondrocytes and stem cells. A variety of methods have been used to obtain large numbers of chondrocytes, including increasing chondrocyte proliferation and stem cell chondrogenic differentiation via cytokines, genes, and proteins. Natural or synthetic small molecule compounds can provide a simple and effective method to promote chondrocyte proliferation, maintain a stable chondrocyte phenotype, and promote stem cell chondrogenic differentiation. Therefore, the study of small molecule compounds is of great importance for cartilage tissue engineering. Herein, we review a series of small molecule compounds and their mechanisms that can promote chondrocyte proliferation, maintain chondrocyte phenotype, or induce stem cell chondrogenesis. The studies in this field represent significant contributions to the research in cartilage tissue engineering and regenerative medicine.

LncRNA MIR4435-2HG inhibits the progression of osteoarthritis through miR-510-3p sponging

Osteoarthritis (OA) is a disorder of diarthrodial joints that can have multiple causes. Long non-coding RNAs (lncRNAs) participate in multiple diseases, including OA. It has recently been reported that the lncRNA microRNA 4435-2HG (MIR4435-2HG) is downregulated in OA tissues; however, the biological role of MIR4435-2HG during OA progression remains unclear. In the present study, interleukin (IL)-1β was used to establish an in vitro model of OA. Protein expressions of matrix metallopeptidase (MMP) 1, MMP13, collagen II, interleukin (IL)-17A, p65, phosphorylated (p)-p65, IκB and p-IκB in CHON-001 cells were detected by western blotting. Gene expressions of IL-17A, MIR4435-2HG and miR-510-3p in tissues or CHON-001 cells were measured by reverse transcription-quantitative PCR and western blotting, respectively. Cell Counting Kit-8 assay and immunofluorescence staining were used to investigate cell proliferation, and cell apoptosis was detected by flow cytometry. The association between MIR4435-2HG, miR-510-3p and IL-17A was investigated using the dual luciferase report assay. MIR4435-2HG and miR-510-3p overexpression were transfected into CHON-001 cells. The results demonstrated that miR4435-2HG overexpression significantly increased proliferation and inhibited apoptosis of CHON-001 cells. In addition, miR-510-3p was identified as the downstream target of MIR4435-2HG, and miR-510-3p directly targeted IL-17A. The results from the present study suggested that MIR4435-2HG could mediate the progression of OA by inactivating the NF-κB signaling pathway. In addition, miR4435-2HG overexpression inhibited OA progression, suggesting that miR4435-2HG may be considered as a potential therapeutic target in OA.