MicroRNA-15a-5p Regulates the Development of Osteoarthritis by Targeting PTHrP in Chondrocytes

Unraveling the molecular landscape of osteoarthritis: A comprehensive review focused on the role of non-coding RNAs

Osteoarthritis (OA) poses a significant global health challenge, with its prevalence anticipated to increase in the coming years. This review delves into the emerging molecular biomarkers in OA pathology, focusing on the roles of various molecules such as metabolites, noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Advances in omics technologies have transformed biomarker identification, enabling comprehensive analyses of the complex pathways involved in OA pathogenesis. Notably, ncRNAs, especially miRNAs and lncRNAs, exhibit dysregulated expression patterns in OA, presenting promising opportunities for diagnosis and therapy. Additionally, the intricate interplay between epigenetic modifications and OA progression highlights the regulatory role of epigenetics in gene expression dynamics. Genome-wide association studies have pinpointed key genes undergoing epigenetic changes, providing insights into the inflammatory processes and chondrocyte hypertrophy typical of OA. Understanding the molecular landscape of OA, including biomarkers and epigenetic mechanisms, holds significant potential for developing innovative diagnostic tools and therapeutic strategies for OA management.

Screening of miR-15a-5p as a potential biomarker for intervertebral disc degeneration through RNA-sequencing

Low back pain (LBP) is a prevalent clinical condition that imposes substantial economic burdens on society. Intervertebral disc degeneration (IVDD) is recognized as a major contributing factor to LBP. Recent studies have highlighted the pivotal role of microRNAs (miRNAs) in regulating the onset and progression of IVDD. Understanding the involvement of miRNAs in IVDD will expand our knowledge of the underlying mechanisms and potentially identify novel therapeutic targets for managing LBP. However, the pathological process of IVDD and the miRNA-mediated pathomechanism in IVDD remain unclear. Herein, we comprehensively analyzed and divided the pathological process of IVDD into three stages based on the analysis by Risbud and colleagues. Results showed that IVDD was especially associated with cell death, oxidative stress, inflammatory and immune response, and extracellular matrix (ECM) metabolism. Subsequently, we obtained human normal and degenerative nucleus pulposus tissues, which were visually confirmed through histological staining techniques such as HE and TUNEL staining. RNA sequencing was then performed on these tissue samples. Additionally, miRNA (GSE116726) and mRNA (GSE56081/GSE70362/GSE23130/GSE34095) datasets were collected from the GEO database. Our analysis revealed that miR-15a-5p was significantly upregulated IVDD, as validated by both RNA sequencing and qRT-PCR experiments. To further refine our findings, bioinformatics analysis was conducted, merging the targets of miR-15a-5p and multiple mRNA datasets, ultimately identifying the overlapping IVDD-associated mRNAs. Notably, many cuproptosis-related genes (CRGs), ferroptosis-related genes, oxidative stress-related genes, and immunity-related genes were potential targets of miR-15a-5p. The miR-15a-5p-mRNA network was constructed using Cytoscape software. Additionally, PPI, functional, and pathway enrichment analyses of the CRGs were also performed. We found that MTF1, one of the CRGs, was highly expressed in IVDD and primarily localized in the nucleus of nucleus pulposus cells. These findings suggest that miR-15a-5p is a potential biomarker in IVDD, and targeting the miR-15a-5p-mRNA signaling pathway may be a promising strategy for treating IVDD diseases.

MicroRNA-15a/β1,4-GalT-I axis contributes to cartilage degeneration via NF-κB signaling in osteoarthritis

OBJECTIVE

Osteoarthritis is a condition characterized by articular cartilage degradation. The increased expression of β1,4-Galactosyltransferase-I (β1,4-GalT-I) in the articular cartilage of osteoarthritis patients was related to an inflammatory response. The aim of this study was to elucidate the role of β1,4-GalT-I in osteoarthritis. This study aimed to determine the function of 1,4-GalT-I in osteoarthritis.

METHODS

The osteoarthritis mouse model with the destabilization of the medial meniscus was established by microsurgical technique. Pathological changes in articular cartilage were observed by hematoxylin and eosin staining and safranin O-fast green staining. Quantitative real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assays were used to observe mRNA and protein expression, respectively. RNA interactions were verified by a luciferase reporter assay. SA-β-Gal staining was used to assess chondrocyte senescence. Immunofluorescence staining was conducted to observe the localization of Nuclear Factor-kappaB (NF-κB).

RESULTS

β1,4-GalT-I and microRNA-15a (miR-15a) show high and low expression in the articular cartilage of osteoarthritis, respectively. MiR-15a inhibits the mRNA translation of β1,4-GalT-I. β1,4-GalT-I promotes extracellular matrix degradation, senescence, and NF-κB activation in IL-1β-stimulated chondrocytes, which can be reversed by overexpression of miR-15a. Intra-articular injection of microRNA-15a ameliorates cartilage degeneration by inhibiting β1,4-GalT-I and phosphorylation of NF-κB in vivo.

CONCLUSION

The authors clarified that the miR-15a/β1,4-GalT-I axis inhibits the phosphorylation of NF-κB thereby inhibiting extracellular matrix degradation and senescence in chondrocytes to alleviate cartilage degeneration in osteoarthritis. MiR-15a and β1,4-GalT-I may serve as potentially effective targets for the future treatment of osteoarthritis.

Osteoarthritis and microRNAs: Do They Provide Novel Insights into the Pathophysiology of This Degenerative Disorder?

Osteoarthritis (OA) is one of the most prevalent degenerative joint diseases in older adults and a leading cause of disability. Recent research studies have evidenced the importance of mi-croRNAs (miRs) in the pathogenesis of OA. In the present review, we focused on current literature findings on dysregulated miRs involved in the pathophysiology of OA. From the 35 case-control studies including OA patients compared to healthy controls, a total of 54 human miRs were identified to be dysregulated in OA. In total, 41 miRs were involved in the pathophysiological processes of OA, including apoptosis, inflammation, and proliferation, having either a protective or a progressive role in OA. The discovery of altered miR levels in OA patients compared to healthy controls determines a better understanding of the molecular mechanisms involved in the pathophysiology of OA and could open novel horizons in the field of orthopedics.

SEMA6D, Negatively Regulated by miR-7, Contributes to C28/I2 chondrocyte's Catabolic and Anabolic Activities via p38 Signaling Pathway

MiR-7 has been recognized as an osteoarthritis (OA-)-promoting factor, but the specific downstream pathway of miR-7 still remains unknown. Further investigation of the molecular regulatory mechanism of miR-7 might help develop a novel therapeutic method for OA. In this study, we revealed that Semaphorin 6D (SEMA6D) was a direct target gene of miR-7 and presented a negative regulatory relation with SEMA6D in vitro and in vivo. SEMA6D could improve OA in rat OA models, as indicated by H&E and Safranin O-Fast green staining, and also μCT analysis. Further evaluation of SEMA6D suggested that SEMA6D promotes the anabolism and reduces the catabolism of C28/I2 chondrocytes via inhibiting the activation of the p38 pathway. The present research illustrated that SEMA6D is a negatively regulatory factor of miR-7 and a pivotal mediator of catabolism and anabolism in C28/I2 chondrocytes. SEMA6D exerts its function via inhibiting the activation of the p38 pathway.

Crosstalk Among circRNA/lncRNA, miRNA, and mRNA in Osteoarthritis

Osteoarthritis (OA) is a joint disease that is pervasive in life, and the incidence and mortality of OA are increasing, causing many adverse effects on people's life. Therefore, it is very vital to identify new biomarkers and therapeutic targets in the clinical diagnosis and treatment of OA. ncRNA is a nonprotein-coding RNA that does not translate into proteins but participates in protein translation. At the RNA level, it can perform biological functions. Many studies have found that miRNA, lncRNA, and circRNA are closely related to the course of OA and play important regulatory roles in transcription, post-transcription, and post-translation, which can be used as biological targets for the prevention, diagnosis, and treatment of OA. In this review, we summarized and described the various roles of different types of miRNA, lncRNA, and circRNA in OA, the roles of different lncRNA/circRNA-miRNA-mRNA axis in OA, and the possible prospects of these ncRNAs in clinical application.

MicroRNA-15a-5p plays a role in osteogenic MC3T3-E1 cells differentiation by targeting PDCD4 (programmed cell death 4) via Wnt/β-catenin dependent signaling pathway

Osteoporosis is defined as a bone condition characterized by bone mass reduction, bone micro-architectural and quality deterioration, leading to compromised strength and increased chances of fracture. Evidence have shown an essential role of microRNAs (miRNAs) in various osteogenic differentiation processes. However, the function of miR-15a-5p in the differentiation of osteogenic cells and possible mechanisms remains unclear. The present study explored the expression of miR-15a-5p in human osteoporosis specimens and during the osteogenic differentiation of MC3T3-E1 cells. Functions of miR-15a-5p were determined using miR-15a-5p mimics and inhibitors. Luciferase assay was used to verify the binding of miR-15a-5p and PDCD4 3ʹUTR. Alizarin Red Staining (ARS) and Alkaline phosphatase (ALP) activity were used to determine the miR-15a-5p role in osteogenic differentiation. Finally, Wnt pathway inhibitor was used to determine the miR-15a-5p/PDCD4/Wnt signaling pathway in regulating osteogenic differentiation. We found miR-15a-5p expression was increased in human osteoporosis specimens and during differentiation of MC3T3-E1 cells. PDCD4 was also identified as a target of miR-15a-5p and was found to be involved in osteogenic differentiation. Further, miR-15a-5p mimics attenuated the effects of PDCD4 overexpression. Finally, use of XAV939 (Wnt pathway inhibitor) downregulated osteogenic differentiation in miR-15a5p/PDCD4/Wnt-dependent signaling pathway. In conclusion, miR-15a-5p induced differentiation of osteoblasts and mineralization by modulating osteoblast differentiation factors, mainly OSX, ALP, OCN, and RUNX2, by inhibiting PDCD4 and Wnt signaling pathways. This study provides a modality for the future use of miR-15a-5p in the treatment and prevention of osteoporosis.

Effects of photobiomodulation and a physical exercise program on the expression of inflammatory and cartilage degradation biomarkers and functional capacity in women with knee osteoarthritis: a randomized blinded study

BACKGROUND

The knee osteoarthritis (OA) is a joint disease characterized by degradation of articular cartilage that leads to chronic inflammation. Exercise programs and photobiomodulation (PBM) are capable of modulating the inflammatory process of minimizing functional disability related to knee OA. However, their association on the concentration of biomarkers related to OA development has not been studied yet. The aim of the present study is to investigate the effects of PBM (via cluster) with a physical exercise program in functional capacity, serum inflammatory and cartilage degradation biomarkers in patients with knee OA.

METHODS

Forty-two patients were randomly allocated in 3 groups: ESP: exercise + sham PBM; EAP: exercise + PBM and CG: control group. Six patients were excluded before finished the experimental period. The analyzed outcomes in baseline and 8-week were: the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) and the evaluation of serum biomarkers concentration (IL-1β, IL-6, IL-8, IL-10 e TNF-α, and CTX-II).

RESULTS

An increase in the functional capacity was observed in the WOMAC total score for both treated groups (p < 0.001) and ESP presents a lower value compared to CG (p < 0.05) the 8-week post-treatment. In addition, there was a significant increase in IL-10 concentration of EAP (p < 0.05) and higher value compared to CG (p < 0.001) the 8-week post-treatment. Moreover, an increase in IL-1β concentration was observed for CG (p < 0.05). No other difference was observed comparing the other groups.

CONCLUSION

Our data suggest that the physical exercise therapy could be a strategy for increasing functional capacity and in association with PBM for increasing IL-10 levels in OA knee individuals.

TRIAL REGISTRATION

ReBEC (RBR-7t6nzr).

The JAK inhibitor Tofacitinib inhibits structural damage in osteoarthritis by modulating JAK1/TNF-alpha/IL-6 signaling through Mir-149-5p

BACKGROUND

Osteoarthritis (OA), a common articular bone degenerative disease, is exacerbated by proinflammatory cytokine signaling. Mounting evidence suggests that epigenetic modifiers, namely microRNAs (miRs), are dysregulated in articular chondrocytes (ACs) during OA.

METHODS

An initial database search led to the identification of miR-149-5p, which was downregulated in clinical OA samples and contributed to chronic inflammation, by increasing TNF-α/IL-6 signaling within the synovium, and OA progression.

RESULTS

We overexpressed miR-149-5p in the human chondrocyte cell lines C20A4 and C28/I2 to examine its role in chondrocyte hypertrophy and osteoclastogenesis and found a significant decrease in IL-6 expression, an increase in SOX9 expression, and a reduction in chondrocyte hypertrophy. We evaluated the therapeutic effects of tofacitinib (JAK inhibitor) by suppressing inflammation and restoring miR-149-5p expression. Tofacitinib-treated C20A4 and C28/I2 cells had a significantly lower expression of JAK/IL-6/TNF-α and an increased level of miR-149-5p. Notably, tofacitinib treatment reduced AC hypertrophy and secretion of RANKL and IL-6. Finally, an OA mouse model was used to evaluate the therapeutic potential of tofacitinib. Intra-articular injection of tofacitinib significantly lowered arthritis scores and bone degradation in treated mice compared with their control counterparts.

CONCLUSION

We show for the first time that tofacitinib suppresses the expression level of JAK1/TNF-α/IL-6 by upregulating miR-149-5p level. Our findings revealed the functional association between proinflammatory JAK1/TNF-α/IL-6 signaling and ACs development and highlight the therapeutic potential of tofacitinib in OA.

Cyclooxygenase-2 regulates PTHrP transcription in human articular chondrocytes and is involved in the pathophysiology of osteoarthritis in rats

Background

Cyclooxygenase-2 (COX-2) inhibitors are prescribed for the management of osteoarthritis (OA)-associated pain and inflammation. However, the role of COX-2 in normal and osteoarthritic articular chondrocytes has not been well investigated. We hypothesize that COX-2 plays a role in articular chondrocytes under normal conditions and during OA progression.

Methods

In vivo COX-2 levels in articular cartilage of normal and papain-induced osteoarthritic rats were compared. The role of COX-2 in human articular chondrocytes (HACs) was tested in vitro by COX-2 overexpression or activity inhibition. The levels of COX-2 and marker gene for normal function or articular cartilage degeneration were evaluated: mRNA by qRT-PCR; proteins by western blotting or immunohistochemistry; and glycosaminoglycan (GAG) by Safranin O-fast green staining. Parathyroid hormone-related protein (PTHrP) promoter activity was detected with luciferase reporter assays.

Results

In the OA rat study, COX-2 and PTHrP were simultaneously increased in osteoarthritic rat chondrocytes, while increased PTHrP levels were reduced by celecoxib, a COX-2 selective inhibitor. The levels of normal cartilage matrices, GAG and type II collagen decreased, while markers of degeneration, collagen type X and MMP13 were elevated in osteoarthritic articular chondrocytes. Celecoxib rescued the loss of GAG and the increased collagen type X and MMP13 levels. In vitro, COX-2 overexpression in HACs significantly increased Col2a1, Col10a1, PTHrP and MMP13 mRNA expression, which was decreased when COX-2 activity was suppressed. More importantly, COX-2 overexpression upregulated the PTHrP transcription, mRNA expression and protein levels.

Conclusion

COX-2 plays a pathophysiological role by preventing terminal differentiation of articular chondrocytes by upregulating PTHrP expression at the early stage of OA progression.

The Translational potential of this article

COX2 up-regulates PTHrP expression in normal and OA articular chondrocytes.

MicroRNA-197 regulates chondrocyte proliferation, migration, and inflammation in pathogenesis of osteoarthritis by targeting EIF4G2

Recent studies have demonstrated that microRNAs (miRNAs) are involved in many pathological conditions including osteoarthritis (OA). In the present study, we aimed to investigate the role of miR-197 in OA and the potential molecular mechanism. The expression levels of miR-197 were detected by quantitative real-time PCR analysis. Cell proliferation and migration abilities were performed by 3-(4,5-dimethylthiazol-2-yl)-2,5-di-phenyltetrazolium bromide and transwell assays. The concentrations of inflammatory cytokines, including IL-1β, IL-6, and TNF-α, were detect using ELISA assay. Furthermore, luciferase reporter and rescue assays were applied to identify the functional target gene of miR-197 in OA. The results showed that miR-197 expression was significantly down-regulated in the OA cartilage tissues compared with normal cartilage tissues, accompanied by up-regulation of EIF4G2 expression. An inverse correlation was found between EIF4G2 and miR-197 expressions in OA cartilage tissues. Treatment with miR-197 mimics promoted the growth and migration abilities of chondrocytes, while miR-197 inhibitors induced the opposite effects. Furthermore, restoration of miR-197 significantly decreased IL-1β, IL-6, and TNF-α expression, whereas knockdown of miR-197 led to a induction in these inflammatory mediators. Moreover, EIF4G2 was predicted and confirmed as a directly target of miR-197. Overexpressed miR-197 could down-regulate EIF4G2 expression in chondrocytes, while miR-197 knockdown could elevate EIF4G2 expression. Additionally, EIF4G2 overexpression reversed the effects of miR-197 mimics on chondrocytes proliferation, migration, and inflammation. Taken together, our study demonstrated that miR-197 promotes chondrocyte proliferation, increases migration, and inhibits inflammation in the pathogenesis of OA by targeting EIF4G2, indicating the potential therapeutic targets of the miR-197/EIF4G2 axis for OA treatment.

Down-regulation of protease-activated receptor 2 ameliorated osteoarthritis in rats through regulation of MAPK/NF-κB signaling pathway in vivo and in vitro

Recently, protease-activated receptor 2 (PAR2) has been proved to be involved in the inflammatory response including osteoarthritis (OA). In the present study, we found that PAR2 antagonist could remarkably improve the pathological condition of OA rats in vivo. In addition, we also found that PAR2 antagonist could suppress the production of inflammatory factors (TNF-α and Cox-2), decrease the levels of MMP-1 and MMP-13, and restrain the levels of P62 proteins and aggravate the expression of LC3-II both in vivo and in vitro. Besides, in vitro, PAR2 antagonist could increase the proliferation and colony formation of chondrocytes induced with IL-1β. Moreover, PAR2 antagonist could decrease the expression of expressions of p-p38, p-IκBα and p-NF-κB in vitro. However, PAR2 agonist exhibited the opposite effects. Furthermore, SB203580, a p38 MAPK inhibitor, could remarkably promote the proliferation of chondrocytes induced with IL-1β, could alleviate the production of TNF-α and Cox-2, could down-regulate the protein expressions of MMP-1 and MMP-13, and could decrease the expression of P62 and increase the expressions of LC3-II of chondrocytes induced with IL-1β. Importantly, SB203580 could reverse the effects of PAR2 agonist on the functions of chondrocytes induced with IL-1β. Taken together, the present data suggest that down-regulation of PAR2 can ameliorate OA through inducing autophagy via regulation of MAPK/NF-κB signaling pathway in vivo and in vitro, and PAR2 can be considered as a potential candidate to treat OA.

Circular RNAs in osteoarthritis: indispensable regulators and novel strategies in clinical implications

Over the past decades, circular RNAs (circRNAs) have emerged as a hot spot and sparked intensive interest. Initially considered as the transcriptional noises, further studies have indicated that circRNAs are crucial regulators in multiple cellular biological processes, and thus engage in the development and progression of many diseases including osteoarthritis (OA). OA is a prevalent disease that mainly affects those aging, obese and post-traumatic population, posing as a major source of socioeconomic burden. Recently, numerous circRNAs have been found aberrantly expressed in OA tissues compared with counterparts. More importantly, circRNAs have been demonstrated to interplay with components in OA microenvironments, such as chondrocytes, synoviocytes and macrophages, by regulation of their proliferation, apoptosis, autophagy, inflammation, or extracellular matrix reorganization. Herein, in this review, we extensively summarize the roles of circRNAs in OA microenvironment, progression, and putative treatment, as well as envision the future directions for circRNAs research in OA, with the aim to provide a novel insight into this field.

Osteopontin inhibits osteoarthritis progression via the OPN/CD44/PI3K signal axis

Chondrocyte degeneration and extracellular matrix component loss are the primary causes of osteoarthritis (OA). OA can be treated by inhibiting chondrocyte degeneration and increasing extracellular matrix component secretion. Osteopontin (OPN), a multifunctional protein, has gained immense attention with regard to its involvement in OA. This study aimed to explore the therapeutic value and mechanism of action of OPN in OA treatment. Results of the histomorphological analysis revealed a worn-off OA cartilage tissue surface, cartilage matrix layer deterioration, and calcium salt deposition. Compared to that in normal chondrocytes, in OA chondrocytes, the OPN, CD44, and PI3K protein and mRNA expression was upregulated. Further, siOPN, rhOPN, and rhOPN plus LS-C179404 interfered with OA chondrocytes. As verified in mice, OPN directly inhibited the expression level of PI3K in OA chondrocytes by binding with CD44. Morphological analysis of the knee joints demonstrated that OPN effectively inhibited OA progression via the OPN/CD44/PI3K signal axis. In conclusion, OPN activates intracellular PI3K signaling molecules by binding to CD44 on the cell surface to cause downstream cascading effects, thereby delaying chondrocyte degeneration and reducing cartilage matrix component loss; therefore, OPN is a potential therapeutic agent for OA.

The Emerging Role of Exosomal Non-coding RNAs in Musculoskeletal Diseases

Exosomes are phospholipid bilayer-enclosed membrane vesicles derived and constitutively secreted by various metabolically active cells. They are capable of mediating hetero- and homotypic intercellular communication by transferring multiple cargos from donor cells to recipient cells. Nowadays, non-coding RNAs (ncRNAs) have emerged as novel potential biomarkers or disease-targeting agents in a variety of diseases. However, the lack of effective delivery systems may impair their clinical application. Recently, accumulating evidence demonstrated that ncRNAs could be efficiently delivered to recipient cells using exosomes as a carrier, and therefore can exert a critical role in musculoskeletal diseases including osteoarthritis, rheumatoid arthritis, osteoporosis, muscular dystrophies, osteosarcoma and other diseases. Herein, we present an extensive review of biogenesis, physiological relevance and clinical implication of exosome-derived ncRNAs in musculoskeletal diseases.

microRNA-1236 promotes chondrocyte apoptosis in osteoarthritis via direct suppression of PIK3R3

AIMS

Chondrocyte degeneration is the main cause of osteoarthritis (OA) and increased evidence suggests that miRNAs could have vital roles in the pathology of various cartilage illnesses. miR-1236 has been found to contribute to inflammation in diseases such as pneumonia. However, the exact role of miR-1236 in OA is poorly understood.

MATERIALS AND METHODS

H&E staining and saffron fixation experiments were employed to determine OA tissues. qRT-PCR and immunohistochemistry were used to detect the expression levels of miR-1236 and PIK3R3. Western blot was performed to detect the expression levels of proteins. Luciferase reporter assays were utilized to investigate the interaction between miR-1236 and PIK3R3. Cell counting assays and AO/EB were used to quantify cell growth and apoptosis.

KEY FINDINGS

miR-1236 was up-regulated in OA knee cartilage compared to normal cartilage. Up-regulated expression of miR-1236 suppressed cell proliferation as well as induced apoptosis in chondrocytes. Bioinformatics identified PIK3R3 as a target of miR-1236. Co-transfection with miR-1236 and PIK3R3 could reverse cell apoptosis induced by the miR-1236 mimic.

SIGNIFICANCE

These data enhance our understanding on the role of miR-1236 in OA and identifies miR-1236 as a potential biomarker or possible treatment target within OA.

LncRNA SNHG1 exerts a protective role in cardiomyocytes hypertrophy via targeting miR-15a-5p/HMGA1 axis

Heart failure preceded by pathological cardiac hypertrophy is a leading cause of death. Long noncoding RNA small nucleolar RNA host gene 1 (SNHG1) was reported to inhibit cardiomyocytes apoptosis, but the role and underlying mechanism of SNHG1 in pathological cardiac hypertrophy have not yet been understood. This study was designed to investigate the role and molecular mechanism of SNHG1 in regulating cardiac hypertrophy. We found that SNHG1 was upregulated during cardiac hypertrophy both in vivo (transverse aortic constriction treatment) and in vitro (phenylephrine [PE] treatment). SNHG1 overexpression attenuated the cardiomyocytes hypertrophy induced by PE, while SNHG1 inhibition promoted hypertrophic response of cardiomyocytes. Furthermore, SNHG1 and high-mobility group AT-hook 1 (HMGA1) were confirmed to be targets of miR-15a-5p. SNHG1 promoted HMGA1 expression by sponging miR-15a-5p, eventually attenuating cardiomyocytes hypertrophy. There data revealed a novel protective mechanism of SNHG1 in cardiomyocytes hypertrophy. Thus, targeting of SNHG1-related pathway may be therapeutically harnessed to treat cardiac hypertrophy.

Adiponectin receptor agonist AdipoRon attenuates calcification of osteoarthritis chondrocytes by promoting autophagy

Cartilage calcification contributes to the development and progression of osteoarthritis (OA). It has been well-investigated adiponectin regulates vascular calcification. The purpose of this study is to investigate the therapeutic value and the molecular mechanism of AdipoRon, an adiponectin receptor agonist, on the chondrocytes calcification. Primary chondrocytes were isolated and cultured from normal cartilage and OA cartilage. The calcification in tissues was evaluated by inductively coupled plasma/atomic emission spectroscopy and alizarin red S staining. The calcification in chondrocytes was determined using the alkaline phosphatase (ALP) staining and an ALP assay kit. The cellular effects of AdipoRon were assessed by immunofluorescence staining and Western blot analysis. We found that calcification was significantly increased in OA cartilage tissues and cells. Importantly, the degree of calcification and ALP activity of the OA chondrocytes was decreased upon the treatment with AdipoRon. The AdipoRon-induced cellular effects, including the reduction of the calcification of chondrocytes and improvement of autophagy, were blocked by dorsomorphin, an 5'-adenosine monophosphate-activated protein kinase (AMPK) inhibitor. Moreover, autophagy activation by AdipoRon was mediated by the AMPK-mammalian target of rapamycin (mTOR) signaling pathway. Our results suggest that AdipoRon significantly alleviates the calcification of OA chondrocytes via activating AMPK-mTOR signaling to promote autophagy. Therefore, AdipoRon could be a potential therapeutic agent for the prevention and treatment of OA.

Tanshinone I Inhibits IL-1β-Induced Apoptosis, Inflammation And Extracellular Matrix Degradation In Chondrocytes CHON-001 Cells And Attenuates Murine Osteoarthritis

Background

Osteoarthritis (OA) is a prevalent degenerative joint disease, which was characterized by inflammation and cartilage degradation. Accumulating evidence has demonstrated that Tanshinone I has an anti-inflammatory effect in various diseases. However, the efficacy of Tanshinone I as an anti-inflammatory agent in OA remains unclear. This study aimed to explore the role of Tanshinone I on OA both in vitro and in vivo.

Methods

CHON-001 cells were treated with IL-1β (10 ng/mL) for 72 hrs to induce OA model in vitro. Meanwhile, CHON-001 cells were pre-treated with 20 μM Tanshinone I for 24 hrs and then stimulated with IL-1β (10 ng/mL) for 72 hrs. CCK-8, immunofluorescence and flow cytometry assays were used to detect the viability, proliferation and apoptosis in CHON-001 cells, respectively. Western blotting assay was used to detect the levels of collagen II, aggrecan, MMP-13, cleaved caspase 1, Gasdermin D, SOX11 and p-NF-κB in CHON-001 cells. In addition, the mouse model of OA was built by anterior cruciate ligament transection (ACLT) in the right knee. Meanwhile, the mice were administrated with 10 or 30 mg/kg Tanshinone I for 8 weeks. Safranin-O/Fast Green staining was used to assess cartilage destruction in a mouse model of OA.

Results

In this study, IL-1β significantly induced apoptosis, extracellular matrix degradation and inflammatory response in CHON-001 cells. Tanshinone I significantly inhibited IL-1β-induced apoptosis in CHON-001 cells. In addition, the IL-1β-induced collagen II, aggrecan degradation, SOX11 downregulation, and MMP-13 and p-NF-κB upregulation in CHON-001 cells were notably reversed by Tanshinone I treatment. Moreover, Tanshinone I alleviated cartilage destruction and synovitis and reduced OARSI scores and subchondral bone thickness in a mouse model of OA.

Conclusion

Our findings showed that Tanshinone I could alleviate the progression of OA in vitro and in vivo. These results demonstrated that Tanshinone I might be regarded as a promising therapeutic agent for the treatment of OA.