Baicalin mitigated IL-1β-Induced osteoarthritis chondrocytes damage through activating mitophagy

USP14 promotes osteoarthritis progression by deubiquitinating FZD8 to activate the Wnt/β-catenin signaling pathway

BACKGROUND

Osteoarthritis (OA) is a chronic degenerative disease and associated with multiple pathogenic factors, such as old age, heredity, obesity, mechanical damage and inflammatory gene mutation. In this study, we aimed to explore the functions of ubiquitin specific peptidase 14 (USP14) in OA development.

METHODS

The in vitro model of OA was constructed by stimulating chondrocytes with IL-1β. qRT-PCR and western blot assays were used for gene expression. MTT assay and EdU assay were manipulated to evaluate cell proliferation. Flow cytometry analysis was conducted for cell apoptosis. ELISA kits were utilized to determine the concentrations of inflammatory cytokines. Co-immunoprecipitation (Co-IP) assay and GST pull-down assay were manipulated to estimate the interaction between USP14 and Frizzled 8 (FZD8). Ubiquitination assay was used to evaluate the deubiquitination of FZD8.

RESULTS

USP14 was highly expression in OA cartilage tissues and IL-1β-triggered chondrocytes. USP14 silencing aggravated the proliferation and repressed the apoptosis, inflammation and extracellular matrix (ECM) degradation of IL-1β-treated chondrocytes. USP14 could interact with FZD8 and regulate FZD8 expression through FZD8 deubiquitination. Moreover, FZD8 overexpression alleviated the effects of UPS14 silencing on IL-1β-treated chondrocyte proliferation, apoptosis, inflammation and ECM degradation. Additionally, USP14 knockdown inhibited Wnt/β-catenin signal pathway via the deubiquitination of FZD8.

CONCLUSION

USP14 repressed IL-1β-treated chondrocyte proliferation and promoted apoptosis, inflammation and ECM degradation by regulating FZD8 expression and Wnt/β-catenin signal pathway.

A Baicalin-Based Functional Polymer in Dynamic Reversible Networks Alleviates Osteoarthritis by Cellular Interactions

Osteoarthritis (OA) is increasingly recognized as a whole-organ disease predominantly affecting the elderly, characterized by typical alterations in subchondral bone and cartilage, along with recurrent synovial inflammation. Despite the availability of various therapeutics and medications, a complete resolution of OA remains elusive. In this study, novel functional hydrogels are developed by integrating natural bioactive molecules for OA treatment. Specifically, baicalin (Bai) is combined with 2-hydroxyethyl acrylate (HEA) to form a polymerizable monomer (HEA-Bai) through esterification, which is subjected to reversible addition-fragmentation chain transfer (RAFT) polymerization to produce Bai-based polymer (Pm). These macromolecules are incorporated into Schiff-base hydrogels, which demonstrate excellent mechanical properties and self-healing performance. Notably, the Bai-based formulations are taken up by fibroblast-like synoviocytes (FLSs), where they regulate glycolysis. Mechanistically, inhibition of yes-associated protein 1 (YAP1) by the formulations suppressed the FLSs glycolysis and reduced the secretion of inflammatory factors, including interleukin 1β (IL-1β), IL-6, and IL-8. Furthermore, the functional hydrogel (AG-Pm)-OC, severing as a lubricant and nutrient, prolonged joint retention of Bai, thereby reducing cartilage degradation and synovial inflammation. Meanwhile, (AG-Pm)-OC alleviated joint pain by targeting the YAP1 signaling and inhibiting macrophage recruitment and polarization. Taken together, this flavonoid-based injectable hydrogel exhibits enhanced biocompatibility and efficacy against OA.

Baicalin attenuates corticosterone-induced hippocampal neuronal injury by activating mitophagy in an AMPK-dependent manner

Defective mitophagy is closely related to the neuronal dysfunction and major depressive disorder (MDD). Our previous study found that baicalin could enhance nip-like protein (NIX)-mediated mitophagy and exhibit antidepressant effects, and predicted that AMPK may be the pharmacological target of baicalin. However, validated experiments are lacking. In the present study, we first demonstrated the effect of baicalin on hippocampal NIX-mediated mitophagy in CORT-induced depressive mice. Secondly, we transfected siRNA to knockdown AMPK, PGC-1α, and NIX respectively in HT22 cells, and detected the effects of baicalin on mitochondrial function, AMPK/PGC-1α/NIX pathway protein expression and mitophagy levels. Finally, AAV-shAMPKα was injected into hippocampal CA3 to knockdown AMPK in mice to validate the antidepressant effects of baicalin in vivo. The results showed that CORT induced depressive-like behaviors, accompanied with neuronal damage, mitochondrial injury, and inhibited mitophagy in the hippocampus, which were prevented by baicalin (20 mg/kg) treatment. In HT22 cells, baicalin remarkably ameliorated mitochondrial dysfunction and mitophagy disturbance induced by CORT, and these protective effects of baicalin were blocked by knockdown of AMPK, PGC-1α and NIX. Moreover, the beneficial effects of baicalin on depressive-like behaviors and NIX-mediated mitophagy were suppressed by knockdown of AMPKα in mice. Our present results further demonstrated that baicalin promotes NIX-mediated mitophagy and improves depression in an AMPK-dependent manner.

Evaluation the protective role of baicalin against H2O2-driven oxidation, inflammation and apoptosis in bovine mammary epithelial cells

Mastitis is one of the most common diseases in dairy farms. During the perinatal period, the bovine mammary epithelial cells (BMECs) of High-yielding dairy cows accelerate metabolism and produce large amounts of reactive oxygen species (ROS). It is one of the primary causes of mastitis and will lead to the breakdown of redox balance, which will induce oxidative stress, inflammation, and apoptosis. Baicalin is a flavonoid substance extracted from the root of natural plant Scutellaria baicalensis, which has anti-inflammatory, anti-oxidant, anti-viral and other biological functions. In this research, hydrogen peroxide (H2O2) was used to construct a mastitis oxidative stress model, and relevant mechanisms were analyzed by immunofluorescence techniques, qRT-PCR and Western Blot to explore how baicalin affects BMECs' oxidative stress and inflammation caused by H2O2, as well as to provide new perspectives on the combined application of baicalin in the prevention and treatment of mastitis. The results demonstrated that baicalin treatment could reduce the accumulation of H2O2-induced intracellular ROS and decrease the expression of inflammatory cytokines Tumor Necrosis Factor-α (TNF-α), interleukin 6 (IL-6), interleukin-1β (IL-1β) and the apoptosis rate. The inhibitory effect of baicalin on H2O2-induced intracellular ROS accumulation and the expression of inflammatory cytokines and apoptotic factors in BMECs was blocked by pretreatment with the Nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor retinoic acid (RA) prior to H2O2 and/or baicalin treatment. In summary, baicalin could served as a natural antioxidant agent to regulate cell apoptosis through its anti-inflammatory, antioxidant and anti-apoptotic effects to combat BMECs damage caused by H2O2.

ENO1 regulates IL-1β-induced chondrocyte inflammation, apoptosis and matrix degradation possibly through the potential binding to CRLF1

In this study, we aim to investigate the role of enolase 1 (ENO1) in osteoarthritis (OA) pathogenic process and to uncover the underlying mechanism. To this end, we used IL-1β to induce an in vitro OA‑like chondrocyte model in human immortalized chondrocyte C-28/I2 cells. We manipulated the expression of ENO1 and cytokine receptor-like factor 1 (CRLF1) in IL-1β-induced C-28/I2 cells using siRNA and/or overexpression and tested their effects on IL-1β-induced pathologies including cell viability, apoptosis and inflammatory cytokine levels (IL-6 and TNF-α), and the expression of extracellular matrix-related enzymes and major mediators in the NF-κB signaling pathway (p-p65, p65, p-IκBα and IκBα). We used co-immunoprecipitation and immunofluorescence imaging to study a possible binding between ENO1 and CRLF1. Our data showed that IL-1β induction elevated ENO1 and CRLF1 expression in C-28/I2 cells. Silencing ENO1 or CRLF1 inhibited the IL-1β-induced cell viability damage, apoptosis, inflammation, and extracellular matrix degradation. The inhibitory effect of silencing ENO1 was reversed by CRLF1 overexpression, suggesting a functional connection between ENO1 and CRLF1, which could be attributed to a binding between these two partners. Our study could help validate the role of ENO1 in OA pathogenies and identify novel therapeutic targets for OA treatment.

Gentiana decoction inhibits liver fibrosis and the activation of hepatic stellate cells via upregulating the expression of Parkin

Liver fibrosis is a wound-healing process. It can be induced by various chronic liver diseases. Liver fibrosis is characterized by the activation of hepatic stellate cells (HSCs), a key event. However, no effective treatment strategies to cure or alleviate liver fibrosis-induced pathologic changes have yet been developed. Traditional Chinese medicine (TCM) exhibits a good anti-fibrosis action, with few side effects. Gentiana decoction, a TCM also called Longdan Xiegan Tang (LXT), is used for purging the liver in clinical settings. However, the role of LXT in preventing liver fibrosis and the underlying regulatory mechanism have not yet been investigated. This study demonstrates that LXT treatment can protect the liver from the injuries resulting from CCl4-induced liver fibrosis in mice and suppress the activation of HSCs. The mice in the LXT group exhibit litter collagen I and HSC activation marker α-smooth muscle actin (α-SMA) expression. Transcriptome sequencing of the mouse liver tissue reveals that the level of Parkin, a mitophagy marker, decreased in CCl4-induced liver fibrosis. Further study shows that the injection of Parkin-overexpression adeno-associated virus (Parkin-AAV) via the tail vein can reduce CCl4-induced liver fibrogenesis in mice. We conducted a mechanistic study also, which suggests that LXT treatment suppresses the activation of HSCs by upregulating the expression of Parkin. Hence, it can be suggested that LXT inhibits liver fibrosis by activating the Parkin signaling pathway.

WITHDRAWN: The dysregulated autophagy in osteoarthritis: Revisiting molecular profile

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PDK4 inhibits osteoarthritis progression by activating the PPAR pathway

BACKGROUND

Osteoarthritis (OA) is a degenerative joint disease caused by the deterioration of cartilage. However, the underlying mechanisms of OA pathogenesis remain elusive.

METHODS

Hub genes were screened by bioinformatics analysis based on the GSE114007 and GSE169077 datasets. The Sprague-Dawley (SD) rat model of OA was constructed by intra-articular injection of a mixture of papain and L-cysteine. Hematoxylin-eosin (HE) staining was used to detect pathological changes in OA rat models. Inflammatory cytokine levels in serum were measured employing the enzyme-linked immunosorbent assay (ELISA). The reverse transcription quantitative PCR (RT-qPCR) was implemented to assess the hub gene expressions in OA rat models. The roles of PDK4 and the mechanism regulating the PPAR pathway were evaluated through western blot, cell counting kit-8 (CCK-8), ELISA, and flow cytometry assays in C28/I2 chondrocytes induced by IL-1β.

RESULTS

Six hub genes were identified, of which COL1A1, POSTN, FAP, and CDH11 expressions were elevated, while PDK4 and ANGPTL4 were reduced in OA. Overexpression of PDK4 inhibited apoptosis, inflammatory cytokine levels (TNF-α, IL-8, and IL-6), and extracellular matrix (ECM) degradation protein expressions (MMP-3, MMP-13, and ADAMTS-4) in IL-1β-induced chondrocytes. Further investigation revealed that PDK4 promoted the expression of PPAR signaling pathway-related proteins: PPARA, PPARD, and ACSL1. Additionally, GW9662, an inhibitor of the PPAR pathway, significantly counteracted the inhibitory effect of PDK4 overexpression on IL-1β-induced chondrocytes.

CONCLUSION

PDK4 inhibits OA development by activating the PPAR pathway, which provides new insights into the OA management.

Astragaloside IV Protects Against IL-1β-Induced Chondrocyte Damage via Activating Autophagy

BACKGROUND

Osteoarthritis (OA) is a chronic inflammatory condition that affects the articular cartilage. Astragaloside IV (AS-IV) constitutes the primary active component of the Chinese herbal medicine Huangqi (Radix Astragali Mongolici). AS-IV demonstrates anti-inflammatory and anti-apoptotic attributes, exhibiting therapeutic potential across various inflammatory and apoptosis-related disorders. Nevertheless, its pharmaceutical effects in OA are yet to be fully defined.

OBJECTIVES

This study aimed to investigate the protective impact of AS-IV on rat chondrocytes treated with IL-1β and ascertain whether autophagy plays a role in this effect.

METHODS

Chondrocytes were isolated and cultivated from the knee joints of neonatal SD mice. The study included the blank control group, the model group, and the AS-IV concentration gradient group (50, 100, 200 μmol/L) to intervene with chondrocytes. The MTT assay was employed to assess cell viability at varying culture periods, enabling the determination of suitable concentration and duration. Subsequently, chondrocytes were treated with the optimal AS-IV concentration and divided into three groups: the model group replicated IL-1β-induced inflammatory chondrocyte injury, the AS-IV group received a co-culture of AS-IV and IL-1β, and a blank control group was established. Changes in cell morphology and structure were observed using ghost pen cyclic peptide staining. ELISA was used to measure TNF-α and GAG levels in cell supernatants. RT-qPCR assessed p62 and LC3 mRNA expression, while Western Blot evaluated p62 and LC3Ⅱ/Ⅰ protein expression.

RESULTS

AS-IV promoted chondrocyte proliferation and concurrently inhibited cell apoptosis. An optimal AS-IV dose of 200 μmol/L and a suitable reaction time of 48 h were identified. Ghost pen cyclic peptide staining indicated that the model group's cytoskeleton exhibited fusiform changes with reduced immunofluorescence intensity, as opposed to the blank control group. The AS-IV group displayed more polygonal cytoskeletal morphology with increased immunofluorescence intensity. AS-IV reduced TNF-α levels and elevated GAG levels in the culture supernatant. Additionally, AS-IV lowered p62 mRNA and protein expression while increasing LC3 mRNA expression in cultured chondrocytes.

CONCLUSION

Our findings suggest that AS-IV mitigates inflammatory chondrocyte injury, safeguarding chondrocytes through a potential autophagy suppression mechanism. These results imply that AS-IV could offer preventive advantages for OA.

Osteoarthritis in the Elderly Population: Preclinical Evidence of Nutrigenomic Activities of Flavonoids

Osteoarthritis (OA) is a degenerative joint disease that is age-related and progressive. It causes the destruction of articular cartilage and underlying bone, often aggravated by inflammatory processes and oxidative stresses. This pathology impairs the quality of life of the elderly, causing pain, reduced mobility, and functional disabilities, especially in obese patients. Phytochemicals with anti-inflammatory and antioxidant activities may be used for long-term treatment of OA, either in combination with current anti-inflammatories and painkillers, or as an alternative to other products such as glucosamine and chondroitin, which improve cartilage structure and elasticity. The current systematic review provides a comprehensive understanding of the use of flavonoids. It highlights chondrocyte, cartilage, and subchondral bone activities, with a particular focus on their nutrigenomic effects. The molecular mechanisms of these molecules demonstrate how they can be used for the prevention and treatment of OA in the elderly population. However, clinical trials are still needed for effective use in clinical practice.

New insight of the pathogenesis in osteoarthritis: the intricate interplay of ferroptosis and autophagy mediated by mitophagy/chaperone-mediated autophagy

Ferroptosis, characterized by iron accumulation and lipid peroxidation, is a form of iron-driven cell death. Mitophagy is a type of selective autophagy, where degradation of damaged mitochondria is the key mechanism for maintaining mitochondrial homeostasis. Additionally, Chaperone-mediated autophagy (CMA) is a biological process that transports individual cytoplasmic proteins to lysosomes for degradation through companion molecules such as heat shock proteins. Research has demonstrated the involvement of ferroptosis, mitophagy, and CMA in the pathological progression of Osteoarthritis (OA). Furthermore, research has indicated a significant correlation between alterations in the expression of reactive oxygen species (ROS), adenosine monophosphate (AMP)-activated protein kinase (AMPK), and hypoxia-inducible factors (HIFs) and the occurrence of OA, particularly in relation to ferroptosis and mitophagy. In light of these findings, our study aims to assess the regulatory functions of ferroptosis and mitophagy/CMA in the pathogenesis of OA. Additionally, we propose a mechanism of crosstalk between ferroptosis and mitophagy, while also examining potential pharmacological interventions for targeted therapy in OA. Ultimately, our research endeavors to offer novel insights and directions for the prevention and treatment of OA.

Sanhuang decoction inhibits autophagy of periodontal ligament fibroblasts during orthodontic tooth movement by activating PI3K-Akt-mTOR pathway

BACKGROUND

Orthodontic tooth movement (OTM) is a typical treatment that corrects malaligned teeth by applying mechanical forces. However, mechanical overload often leads to damage of PDL fibroblasts. Sanhuang decoction (SHD) is commonly used to inhibit inflammation and oxidative stress. However, the mechanism of SHD for OTM treatment is still unclear. Therefore, this study attempts to explore the underlying mechanism through relevant experiments.

METHODS

In the present paper, we established a OTM rat model and further explored the effects of SHD on the PDL of OTM rats. The OTM model and effects of SHD were determined by micro-CT, and the PDL pathological changes, PDL width and capillaries in PDL were observed by H&E staining. Subsequently, the ROS levels in PDL was determined using flow cytometry analysis with DCFH-DA staining, MDA contents and antioxidative enzymes activities were also measured using commercial kits. Furthermore, the autophagy of PDL fibroblasts and proteins in the PI3K/Akt/mTOR pathway were detected using immunoluminescence, qPCR and western blotting assays.

RESULTS

The results showed SHD treatment can alleviate the decrease of PDL cells and capillaries induced by OTM, and improve the MDA and ROS levels in PDL, as well as enhance the activities of SOD and GSH-Px. Further experiments indicated SHD decreased the autophagy levels of PDL fibroblasts via promoting the phosphorylation levels of mTOR, PI3K and Akt proteins.

CONCLUSION

SHD inhibited autophagy of periodontal ligament fibroblasts during orthodontic tooth movement by inhibiting oxidative stress via activating PI3K-Akt-mTOR pathway. Our present findings suggested SHD treatment would be useful for management of the possible disorders occurs in orthodontic tooth movement therapy.

The emerging role of lncRNAs in osteoarthritis development and potential therapy

Osteoarthritis impairs the functions of various joints, such as knees, hips, hands and spine, which causes pain, swelling, stiffness and reduced mobility in joints. Multiple factors, including age, joint injuries, obesity, and mechanical stress, could contribute to osteoarthritis development and progression. Evidence has demonstrated that genetics and epigenetics play a critical role in osteoarthritis initiation and progression. Noncoding RNAs (ncRNAs) have been revealed to participate in osteoarthritis development. In this review, we describe the pivotal functions and molecular mechanisms of numerous lncRNAs in osteoarthritis progression. We mention that long noncoding RNAs (lncRNAs) could be biomarkers for osteoarthritis diagnosis, prognosis and therapeutic targets. Moreover, we highlight the several compounds that alleviate osteoarthritis progression in part via targeting lncRNAs. Furthermore, we provide the future perspectives regarding the potential application of lncRNAs in diagnosis, treatment and prognosis of osteoarthritis.

MATN3 delivered by exosome from synovial mesenchymal stem cells relieves knee osteoarthritis: Evidence from in vitro and in vivo studies

Background

Synovial mesenchymal stem cell (SMSC) exerts chondroprotective effects in osteoarthritis (OA) clinical models. However, the regulatory potentials of SMSC-derived exosomes (SMSC-Exo) in OA still need to be discovered, which attracted our attention.

Methods

The destabilization of the medial meniscus surgery was performed on the knee joints of a mouse OA model, followed by injection of SMSC-Exo. In addition, SMSC-Exo was administrated to mouse chondrocytes to observe the functional and molecular alterations.

Results

Both of SMSC-Exo and overexpression of Matrilin-3 (MATN3) alleviated cartilage destruction and suppressed degradation of extracellular matrix (ECM) in the OA rat model. In addition, assays concerning the in vitro OA model induced by IL-1β showed that SMSC-Exo could promote chondrocyte viability and inhibit autophagy defects. Furthermore, SMSC-Exo achieved the chondroprotective effects through the delivery of MATN3/IL-17A, and MATN3 could suppress the activation of PI3K/AKT/mTOR signaling through IL-17A.

Conclusion

SMSC-Exo exerts beneficial therapeutic effects on OA by preventing ECM degradation and autophagy defects by delivering MATN3/IL-17A.

The Translational Potential of this Article

The translational potential of this study is not only limited to the treatment of knee osteoarthritis but also provides new insights for the treatment of other joint diseases by exploring the mechanism of MATN3. In addition, SMSCExo, as a novel drug carrier, has great potential for treating and diagnosing other diseases. With further research, these findings will provide new directions for developing personalized and innovative treatment options.