Expression and pathological effects of periostin in human osteoarthritis cartilage

Suppressive Activity of Boiogito, a Japanese Traditional Kampo Medicine, on Periostin Secretion in Human Fibroblast-Like Synoviocytes In Vitro

Background Knee osteoarthritis (KOA) is a prevalent degenerative disease that affects the knee joints, particularly among individuals aged over 40 years. It leads to pain, stiffness, and reduced quality of life; affects approximately 300 million individuals worldwide; and is increasing, particularly in developed nations. Although treatments for KOA range from conservative measures to surgical interventions, such as total knee arthroplasty (TKA), the financial burden of TKA in many countries underscores the urgent need for effective conservative therapies. The pathophysiology of KOA involves articular cartilage degeneration, increased subchondral bone turnover, synovitis, and periarticular soft tissue contracture. Abnormal bone turnover, intensified by factors, such as weight gain and knee injury, precedes cartilage degeneration. Synovitis, characterized by inflammation in the synovial tissue, plays a crucial role in perpetuating the disease by triggering a cascade of catabolic and proinflammatory mediators, including cytokines, such as interleukin (IL)-1 beta, tumor necrosis factor-alpha, and IL-13. Periostin, an extracellular matrix protein, is implicated in KOA progression, with its levels increasing with disease severity. Materials & methods In this study, the preventive effect of boiogito (BOT), a traditional herbal medicine, on periostin secretion in human fibroblast-like synoviocytes (hFLS) stimulated by IL-13 was investigated. Synoviocyte Growth Medium and recombinant human IL-13 were used for cell culture and stimulation. BOT was dissolved in phosphate-buffered saline and applied to cell cultures. Periostin secretion and mRNA expression were measured using enzyme-linked immunosorbent assay and quantitative reverse transcription polymerase chain reaction, respectively. Cell viability was assessed using an MTT assay, and signal transducer and activator of transcription factor 6 (STAT6) phosphorylation was examined using Western blotting. Results IL-13 stimulation of hFLS significantly increased periostin secretion, with levels rising above 20 ng/mL after 72 h of stimulation. Pretreatment with BOT dose-dependently suppressed periostin secretion, with doses of 1,000 μg/mL significantly reducing periostin levels. Furthermore, BOT inhibited periostin mRNA expression and STAT6 phosphorylation in IL-13-stimulated hFLS, suggesting its potential in modulating IL-13-mediated inflammatory pathways in KOA. Conclusion This study demonstrated the preventive effect of BOT on periostin secretion in IL-13-stimulated hFLS, highlighting its potential as a therapeutic agent for KOA. By inhibiting periostin production and downstream signaling pathways, BOT may offer a promising conservative treatment option for KOA, addressing the inflammatory cascade implicated in disease progression. Further research is warranted to elucidate the specific herbal components responsible for the therapeutic effects of BOT and to validate its efficacy in clinical settings.

IL-6 induces periostin production in human ACL remnants: a possible mechanism causing post-traumatic osteoarthritis

OBJECTIVE

Perostin (POSTN) and IL-6 consistently elevated after ACL injury, and ACL has been proposed as the major source of POSTN. However, there is a lack of evidence whether IL-6 induces ACL remnants to produce POSTN. This study aimed to investigate the effect of IL-6 on POSTN production in ACL fibroblasts, which may help us understand more about the mechanism of PTOA after ACL injury and ACL reconstruction.

METHODS

ACL remnants were harvested from 27 patients undergoing ACL reconstruction. Quantitative real-time polymerase chain reaction (PCR) was performed to examine the POSTN gene expression of ACL fibroblasts after treatment of different concentrations of IL-6. The POSTN protein production of ACL fibroblasts was determined using western blot analysis. The blockers of possible signaling pathways, including PI3K/Akt, Ras/MAPK, and JAK/STAT pathways, were added to test whether the effect of IL-6 on ACL fibroblast could be attenuated. ACL fibroblast and chondrocyte co-culture was carried out to determine the influence of ACL and IL-6 on chondrocytes.

RESULTS

Quantitative real-time PCR showed that IL-6 time-dependently and dose-dependently increased POSTN gene expression of ACL fibroblast. Western blot analysis also revealed that IL-6 dose-dependently induced POSTN protein production. Regarding the chronicity of ACL injury, the POSTN protein production was comparable between ACL remnants which were derived within 3 months of injury and at least 6 months after injury. PI3K/Akt blockers could attenuate the effect of IL-6 on ACL remnants, whereas Ras/MAPK and JAK/STAT did not decrease POSTN production. The coexistence of ACL and IL-6 induced more MMP-13 and ADAMTS-4 by chondrocytes.

CONCLUSIONS

IL-6 induced ACL remnants to produce POSTN. This effect could be attenuated by the PI3K/Akt blocker. Coexistence of IL-6 and ACL remnants may accelerate post-traumatic arthritis.

Mechanisms of tissue degeneration mediated by periostin in spinal degenerative diseases and their implications for pathology and diagnosis: a review

Periostin (POSTN) serves a dual role as both a matricellular protein and an extracellular matrix (ECM) protein and is widely expressed in various tissues and cells. As an ECM protein, POSTN binds to integrin receptors, transduces signals to cells, enabling cell activation. POSTN has been linked with various diseases, including atopic dermatitis, asthma, and the progression of multiple cancers. Recently, its association with orthopedic diseases, such as osteoporosis, osteoarthritis resulting from cartilage destruction, degenerative diseases of the intervertebral disks, and ligament degenerative diseases, has also become apparent. Furthermore, POSTN has been shown to be a valuable biomarker for understanding the pathophysiology of orthopedic diseases. In addition to serum POSTN, synovial fluid POSTN in joints has been reported to be useful as a biomarker. Risk factors for spinal degenerative diseases include aging, mechanical stress, trauma, genetic predisposition, obesity, and metabolic syndrome, but the cause of spinal degenerative diseases (SDDs) remains unclear. Studies on the pathophysiological effects of POSTN may significantly contribute toward the diagnosis and treatment of spinal degenerative diseases. Therefore, in this review, we aim to examine the mechanisms of tissue degeneration caused by mechanical and inflammatory stresses in the bones, cartilage, intervertebral disks, and ligaments, which are crucial components of the spine, with a focus on POSTN.

Synovial Fluid Proteomics From Serial Aspirations of ACL-Injured Knees Identifies Candidate Biomarkers

BACKGROUND

Anterior cruciate ligament (ACL) tears often result in knee effusion and an increased risk for developing knee osteoarthritis (OA) in the long run. The molecular profile of these effusions could be informative regarding initial steps in the development of posttraumatic OA after an ACL tear.

HYPOTHESIS

The proteomics of knee synovial fluid changes over time after ACL injury.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Synovial fluid was collected from patients with an acute traumatic ACL tear presenting to the office for evaluation (18.31 ± 19.07 days from injury) (aspiration 1) and again at the time of surgery (35.41 ± 58.15 days after aspiration 1 (aspiration 2). High-resolution liquid chromatography mass spectrometry was used to assess the quantitative protein profile of synovial fluid, and differences in protein profile between the 2 aspirations were determined computationally.

RESULTS

A total of 58 synovial fluid samples collected from 29 patients (12 male, 17 female; 12 isolated ACL tear, 17 combined ACL and meniscal tear) with a mean age and body mass index of 27.01 ± 12.78 years and 26.30 ± 4.93, respectively, underwent unbiased proteomics analysis. The levels of 130 proteins in the synovial fluid changed over time (87 high, 43 low). Proteins of interest that were significantly higher in aspiration 2 included CRIP1, S100A11, PLS3, POSTN, and VIM, which represent catabolic/inflammatory activities in the joint. Proteins with a known role in chondroprotection and joint homeostasis such as CHI3L2 (YKL-39), TNFAIP6/TSG6, DEFA1, SPP1, and CILP were lower in aspiration 2.

CONCLUSION

Synovial fluid from knees with ACL tears exhibits an increased burden of inflammatory (catabolic) proteins relevant to OA with reduced levels of chondroprotective (anabolic) proteins.

CLINICAL RELEVANCE

This study identified a set of novel proteins that provide new biological insights into the aftermath of ACL tears. Elevated inflammation and decreased chondroprotection could represent initial disruption of homeostasis, potentially initiating the development of OA. Longitudinal follow-up and mechanistic studies are necessary to assess the functional role of these proteins in the joint. Ultimately, these investigations could lead to better approaches to predict and possibly improve patient outcomes.

Gene Expression in Glenoid Articular Cartilage Varies Across Acute Instability, Chronic Instability, and Osteoarthritis

BACKGROUND

Shoulder instability is a common pathology associated with an elevated risk of osteoarthritis (OA). Little is known about gene expression in the cartilage of the glenohumeral joint after dislocation events, particularly as it relates to the risk of posttraumatic OA. This study tested the hypothesis that gene expression in glenoid cartilage varies among acute instability (<3 dislocations), chronic instability (≥3 dislocations), and OA.

METHODS

Articular cartilage was collected from the anteroinferior glenoid of consenting patients undergoing shoulder stabilization surgery (n = 17) or total shoulder arthroplasty (n = 16). Digital quantitative polymerase chain reaction was used to assess the relative expression of 57 genes (36 genes from OA risk allele studies, 21 genes from differential expression studies), comparing (1) OA versus instability (acute and chronic combined), (2) acute versus chronic instability, (3) OA versus acute instability, and (4) OA versus chronic instability.

RESULTS

The expression of 11 genes from OA risk allele studies and 9 genes from differential expression studies was significantly different between cartilage from patients with instability and those with OA. Pro-inflammatory genes from differential expression studies and genes from OA risk allele studies were more highly expressed in cartilage in the OA group compared with the instability group, which expressed higher levels of extracellular matrix and pro-anabolic genes. The expression of 14 genes from OA risk allele studies and 4 genes from differential expression studies, including pro-inflammatory genes, anti-anabolic genes, and multiple genes from OA risk allele studies, was higher in the acute instability group compared with the chronic instability group. Cartilage in the OA group displayed higher expression of CCL3, CHST11, GPR22, PRKAR2B, and PTGS2 than cartilage in the group with acute or chronic instability. Whereas cartilage in both the acute and chronic instability groups had higher expression of collagen genes, cartilage in the OA group had expression of a subset of genes from OA risk allele studies or from differential expression studies that was lower than in the acute group and higher than in the chronic group.

CONCLUSIONS

Glenoid cartilage has an inflammatory and catabolic phenotype in shoulders with OA but an anabolic phenotype in shoulders with instability. Cartilage from shoulders with acute instability displayed greater (cellular) metabolic activity compared with shoulders with chronic instability.

CLINICAL RELEVANCE

This exploratory study identified genes of interest, such as CCL3, CHST11, GPR22, PRKAR2B, and PTGS2, that have elevated expression in osteoarthritic glenoid cartilage. These findings provide new biological insight into the relationship between shoulder instability and OA, which could lead to strategies to predict and potentially modify patients' risk of degenerative arthritis due to shoulder instability.

Periostin regulation and cartilage degradation early after anterior cruciate ligament reconstruction

OBJECTIVE AND DESIGN

The purpose of this study was to explore pathological processes during the first 4 weeks after anterior cruciate ligament reconstruction (ACLR).

SUBJECTS

Sixteen ACL-injured patients (8 females/8 males, mean age = 19.1, mean BMI = 28.6).

METHODS

Arthrocentesis was performed 1 and 4 weeks after ACLR. Proteins in the synovial fluid were identified using nanoLC-ESI-MS/MS. Differentially up- or down-regulated proteins were identified and quantified, and a pathway analysis was performed. All identified proteins were mapped into a protein-protein interaction (PPI) network, and networks of PPIs with a combined score > 0.9 were then visualized.

RESULTS

Seven pathways were upregulated after ACLR: PI3K-AKT signaling pathway, extracellular matrix (ECM)-receptor interaction, focal adhesion, protein digestion and absorption, ameobiasis, and platelet activation. Network analyses identified 8 proteins that were differentially upregulated with strong PPI interactions (periostin and 7 collagen-related proteins). Increases in periostin moderately correlated with increases in a synovial fluid biomarker of type II cartilage degradation (ρ = 0.51, p = 0.06).

CONCLUSION

Pro-inflammatory pathways and periostin were upregulated after ACLR. Periostin demonstrated strong network connections with markers of collagen breakdown, and future work is needed to determine whether periostin may offer a biomarker of early cartilage degradation after ACLR and/or play an active role in early post-traumatic osteoarthritis (PTOA) progression.

Periostin splice variants affect craniofacial growth by influencing chondrocyte hypertrophy

INTRODUCTION

Periostin, an extracellular matrix protein, plays an important role in osteogenesis and is also known to activate several signals that contribute to chondrogenesis. The absence of periostin in periostin knockout mice leads to several disorders such as craniosynostosis and periostitis. There are several splice variants with different roles in heart disease and myocardial infarction. However, little is known about each variant's role in chondrogenesis, followed by bone formation. Therefore, the aim of this study is to investigate the role of several variants in chondrogenesis differentiation and bone formation in the craniofacial region. Periostin splice variants included a full-length variant (Control), a variant lacking exon 17 (ΔEx17), a variant lacking exon 21 (ΔEx21), and another variant lacking both exon 17 and 21 ***(ΔEx17&21).

MATERIALS AND METHODS

We used C56BL6/N mice (n = 6) for the wild type (Control)*** and the three variant type mice (n = 6 each) to identify the effect of each variant morphologically and histologically. Micro-computed tomography demonstrated a smaller craniofacial skeleton in ΔEx17s, ΔEx21s, and ΔEx17&21s compared to Controls, especially the mandibular bone. We, thus, focused on the mandibular condyle.

RESULTS

The most distinctive histological observation was that each defected mouse appeared to have more hypertrophic chondrocytes than Controls. Real-time PCR demonstrated the differences among the group. Moreover, the lack of exon 17 or exon 21 in periostin leads to inadequate chondrocyte differentiation and presents in a diminutive craniofacial skeleton.

DISCUSSION

Therefore, these findings suggested that each variant has a significant role in chondrocyte hypertrophy, leading to suppression of bone formation.

Periostin increased by mechanical stress upregulates interleukin-6 expression in the ligamentum flavum

Ligamentum flavum (LF) hypertrophy is a major cause of lumbar spinal canal stenosis. Although mechanical stress is thought to be a major factor involved in LF hypertrophy, the exact mechanism by which it causes hypertrophy has not yet been fully elucidated. Here, changes in gene expression due to long-term mechanical stress were analyzed using RNA-seq in a rabbit LF hypertrophy model. In combination with previously reported analysis results, periostin was identified as a molecule whose expression fluctuates due to mechanical stress. The expression and function of periostin were further investigated using human LF tissues and primary LF cell cultures. Periostin was abundantly expressed in human hypertrophied LF tissues, and periostin gene expression was significantly correlated with LF thickness. In vitro, mechanical stress increased gene expressions of periostin, transforming growth factor-β1, α-smooth muscle actin, collagen type 1 alpha 1, and interleukin-6 (IL-6) in LF cells. Periostin blockade suppressed the mechanical stress-induced gene expression of IL-6 while periostin treatment increased IL-6 gene expression. Our results suggest that periostin is upregulated by mechanical stress and promotes inflammation by upregulating IL-6 expression, which leads to LF degeneration and hypertrophy. Periostin may be a pivotal molecule for LF hypertrophy and a promising therapeutic target for lumbar spinal stenosis.

Prediction and analysis of osteoarthritis hub genes with bioinformatics

Background

Osteoarthritis (OA) is the most common type of arthritis. OA can cause joint pain, stiffness, and loss of function. The pathogenesis of OA is not completely clear. Moreover, there is no effective treatment, and clinical management is limited to symptomatic relief or joint surgery. This study utilized bioinformatics to analyze normal and OA articular cartilage samples to find biomarkers and therapeutic targets for OA.

Methods

The GSE169077 gene chip dataset was downloaded from the public gene chip data platform of the National Biotechnology Information Center. The dataset included 6 samples of OA tissues and 5 samples of healthy cartilage tissues. Differentially expressed genes (DEGs) were screened using the R language "limma" function package under the threshold of log₂[fold change (FC)] ≥2 and a P value <0.05. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) signal pathways of the target genes were enriched and analyzed using the database for annotation, visualization, and integrated discovery (DAVID), and a protein-protein interaction (PPI) network was further constructed using the search tool for the retrieval of interacting genes/proteins (STRING) database. The coexpression relationship of the genes in the module was visualized and screened with Cytoscape.

Results

A total of 27 DEGs were identified, including 9 downregulated genes and 18 upregulated genes. GO signal pathway enrichment analysis showed involvement in hypoxic response, fibrous collagen trimer, and extracellular matrix structural components. KEGG analysis demonstrated associations with protein digestion and absorption, extracellular matrix receptor interaction, and the peroxisome proliferator-activated receptor signal pathway, among several other pathways. A PPI network was obtained through STRING analysis, and the results were imported into Cytoscape software. The 27 DEGs were sequenced by the cytoHubba plug-in by various calculation methods, and 5 hub genes (COL1A1, COL1A2, POSTN, BMP1, and MMP13) were finally selected. These genes were analyzed by PPI again and annotated with GO and KEGG in different colors.

Conclusions

Bioinformatics technology effectively identified differential genes in the knee cartilage tissue of healthy controls and patients with OA, providing opportunities to further explore the mechanism and treatment of OA on a transcriptional level.

The Multiple Roles of Periostin in Non-Neoplastic Disease

Periostin, identified as a matricellular protein and an ECM protein, plays a central role in non-neoplastic diseases. Periostin and its variants have been considered to be normally involved in the progression of most non-neoplastic diseases, including brain injury, ocular diseases, chronic rhinosinusitis, allergic rhinitis, dental diseases, atopic dermatitis, scleroderma, eosinophilic esophagitis, asthma, cardiovascular diseases, lung diseases, liver diseases, chronic kidney diseases, inflammatory bowel disease, and osteoarthrosis. Periostin interacts with protein receptors and transduces signals primarily through the PI3K/Akt and FAK two channels as well as other pathways to elicit tissue remodeling, fibrosis, inflammation, wound healing, repair, angiogenesis, tissue regeneration, bone formation, barrier, and vascular calcification. This review comprehensively integrates the multiple roles of periostin and its variants in non-neoplastic diseases, proposes the utility of periostin as a biological biomarker, and provides potential drug-developing strategies for targeting periostin.

Periostin: an emerging activator of multiple signaling pathways

Matricellular proteins are responsible for regulating the microenvironment, the behaviors of surrounding cells, and the homeostasis of tissues. Periostin (POSTN), a non-structural matricellular protein, can bind to many extracellular matrix proteins through its different domains. POSTN usually presents at low levels in most adult tissues but is highly expressed in pathological sites such as in tumors and inflamed organs. POSTN can bind to diverse integrins to interact with multiple signaling pathways within cells, which is one of its core biological functions. Increasing evidence shows that POSTN can activate the TGF-β, the PI3K/Akt, the Wnt, the RhoA/ROCK, the NF-κB, the MAPK and the JAK pathways to promote the occurrence and development of many diseases, especially cancer and inflammatory diseases. Furthermore, POSTN can interact with some pathways in an upstream and downstream relationship, forming complicated crosstalk. This article focuses on the interactions between POSTN and different signaling pathways in diverse diseases, attempting to explain the mechanisms of interaction and provide novel guidelines for the development of targeted therapies.

Serum periostin level is not sufficient to serve as a clinically applicable biomarker of osteoarthritis

BACKGROUND

Emerging knowledge has highlighted the role of periostin (POSTN) in osteoarthritis (OA) process; however, whether POSTN is suitable as a biomarker of OA remains unclear. This study aimed to investigate the potential value of POSTN as a biomarker of OA.

METHODS

Ten 6-month-old female Sprague-Dawley (SD) rats were used in this study. Five rats underwent ovariectomy (OVX) operation and the others were carried out sham operation. Thirty-two patients with OA and eighteen patients who had meniscus injuries or ligament injuries but with intact articular cartilages were recruited in this study from January to July 2019 at the Peking University International Hospital. We first detected the expression of POSTN in the cartilage of OVX induced OA rats and different compartments of the knee joint in patients with OA using immunohistochemistry. Besides, serum POSTN levels in patients with or without OA were examined using enzyme-linked immunosorbent assay (ELISA). The associations among serum POSTN levels, clinical symptoms, and radiological severity were assessed according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and, Kellgren-Lawrence (KL) grading, respectively. Finally, multivariable cumulative link models were established to evaluate the validity of serum POSTN level as a predictor of knee OA.

RESULTS

The significantly higher POSTN expression was found in OVX-OA rats than Sham rats, while, the expression of POSTN was significantly higher in the torn cartilage of patients with OA. However, the serum POSTN level did not differ significantly between patients with and without OA. Additionally, we found no remarkable associations between serum POSTN level and WOMAC scores and KL grading. Subsequent analysis revealed that serum POSTN was not a significant predictor of OA.

CONCLUSION

Thus, although POSTN may be involved OA process and local POSTN is valuable in disease diagnosis and distinguishing of the severity of disease, its serum level is not sufficient to serve as a candidate biomarker of OA given the current analysis technology.

Self-amplifying loop of NF-κB and periostin initiated by PIEZO1 accelerates mechano-induced senescence of nucleus pulposus cells and intervertebral disc degeneration

Abnormal mechanical load is a main risk factor of intervertebral disc degeneration (IDD), and cellular senescence is a pathological change in IDD. In addition, extracellular matrix (ECM) stiffness promotes human nucleus pulposus cells (hNPCs) senescence. However, the molecular mechanism underlying mechano-induced cellular senescence and IDD progression is not yet fully elucidated. First, we demonstrated that mechano-stress promoted hNPCs senescence via NF-κB signaling. Subsequently, we identified periostin as the main mechano-responsive molecule in hNPCs through unbiased sequencing, which was transcriptionally upregulated by NF-κB p65; moreover, secreted periostin by senescent hNPCs further promoted senescence and upregulated the catabolic process in hNPCs through activating NF-κB, forming a positive loop. Both Postn (encoding periostin) knockdown via siRNA and periostin inactivation via neutralizing antibodies alleviated IDD and NPCs senescence. Furthermore, we found that mechano-stress initiated the positive feedback of NF-κB and periostin via PIEZO1. PIEZO1 activation by Yoda1 induced severe IDD in rat tails without compression, and Postn knockdown alleviated the Yoda1-induced IDD in vivo. Here, we reported for the first time that self-amplifying loop of NF-κB and periostin initiated via PIEZO1 under mechano-stress accelerated NPCs senescence, leading to IDD. Furthermore, periostin neutralizing antibodies, which may serve as potential therapeutic agents for IDD, interrupted this loop.

Reduced dynamic loads due to hip dislocation induce acetabular cartilage degeneration by IL-6 and MMP3 via the STAT3/periostin/NF-κB axis

Developmental dysplasia of the hip (DDH) is characterized by anatomical abnormalities of the hip joint, ranging from mild acetabular dysplasia to hip subluxation and eventually dislocation. The mechanism underlying the cartilage degeneration of the hip joints exposed to reduced dynamic loads due to hip dislocation remains unknown. We established a rodent hip dislocation (disarticulation; DA) model of DDH (DA-DDH rats and mice) by swaddling. Expression levels of periostin (Postn) and catabolic factors, such as interleukin-6 (IL-6) and matrix metalloproteinase 3 (Mmp3), increased and those of chondrogenic markers decreased in the acetabular cartilage of the DA-DDH models. Postn induced IL-6 and Mmp3 expression in chondrocytes through integrin αVβ3, focal adhesion kinase, Src, and nuclear factor-κB (NF-κB) signaling. The microgravity environment created by a random positioning machine induced Postn expression in chondrocytes through signal transducer and activator of transcription 3 (STAT3) signaling. IL-6 stimulated Postn expression via STAT3 signaling. Furthermore, cartilage degeneration was suppressed in the acetabulum of Postn^−/− DA-DDH mice compared with that in the acetabulum of wild type DA-DDH mice. In summary, reduced dynamic loads due to hip dislocation induced acetabular cartilage degeneration via IL-6 and MMP3 through STAT3/periostin/NF-κB signaling in the rodent DA-DDH models.

Periostin promotes nucleus pulposus cells apoptosis by activating the Wnt/β-catenin signaling pathway

Intervertebral disc (IVD) degeneration (IVDD) is closely linked to degenerative spinal disease, resulting in disability, poor quality of life, and financial burden. Apoptosis of nucleus pulposus (NP) cells (NPCs) is a key pathological basis of IVDD. Periostin (POSTN), an extracellular matrix protein, is expressed in many tissues, whereas its abnormal expression is associated with IVDD. The conventional Wnt/β-catenin pathway is also involved in IVDD and contributes to NPCs apoptosis. However, research on the mechanisms of POSTN in IVDD is lacking. This study investigated the relationship between POSTN and β-catenin expression in degenerated IVDs. We detected the expression of POSTN, β-catenin, and cleaved-caspase-3 (C-caspase3) in degenerated and non-degenerated IVD tissues of different grades (n = 8) using RT-qPCR, immunohistochemical staining, and western blotting analysis. Next, we explored the effects of recombinant periostin (rPOSTN) and isoquercitrin (Iso), an inhibitor of the Wnt/β-catenin pathway, on NPCs apoptosis. Finally, we inhibited the expression of POSTN in degenerated NPCs in vivo and investigated the anti-apoptotic effect. The expression of β-catenin, POSTN, and C-caspase3 in severe degenerative IVDs was significantly higher than that in mild degenerative IVDs. These findings were confirmed in rat and cell-based degenerative models. When treated with rPOSTN, the Wnt/β-catenin pathway activity and cell apoptosis were time- and dose-dependent. However, rPOSTN-induced NPCs apoptosis decreased after iso-induced inhibition of the Wnt/β-catenin pathway. POSTN inhibition reduced apoptosis but was restored by rPOSTN re-addition. Lastly, POSTN inhibition ameliorated puncture-induced IVDD in vivo. Overall, our study demonstrated that POSTN promotes NPCs apoptosis and aggravates degeneration by activating the Wnt/β-catenin pathway.

Identification of Adamts4 as a novel adult cardiac injury biomarker with therapeutic implications in patients with cardiac injuries

Pathological cardiac remodeling as an aftermath of a severe cardiac injury can lead to ventricular dysfunction and subsequent heart failure. Adamts4, a metalloproteinase, and disintegrin with thrombospondin-like motif, involved in the turnover of certain extracellular matrix molecules and pathogenesis of osteoarthritis, also plays a role in cardiac remodeling although little is presently known about its expression and function in the heart. Here, we have investigated the dynamic expression pattern of Adamts4 during cardiogenesis and also in the adult heart. To our surprise, adult cardiac injury reactivated Adamts4 expression concomitant with fibrosis induction. To better understand the mechanism, cultured H9c2 cardiomyocyte cells were subjected to ROS injury and Hypoxia. Moreover, through combinatorial treatment with SB431542 (an inhibitor of Tgf-β1), and Adamts4 siRNA mediated gene knockdown, we were able to decipher a regulatory hierarchy to the signal cascade being at the heart of Tgf-β regulation. Besides the hallmark expression of Adamts4 and Tgf-β1, expression of other fibrosis-related markers like Collagen-III, alpha-SMA and Periostin were also assessed. Finally, increased levels of Adamts4 and alpha-SMA proteins in cardiac patients also resonated well with our animal and cell culture studies. Overall, in this study, we highlight, Adamts4 as a novel biomarker of adult cardiac injury.

Identification of mechanics-responsive osteocyte signature in osteoarthritis subchondral bone

Aims

Osteoarthritis (OA) is a common degenerative joint disease. The osteocyte transcriptome is highly relevant to osteocyte biology. This study aimed to explore the osteocyte transcriptome in subchondral bone affected by OA.

Methods

Gene expression profiles of OA subchondral bone were used to identify disease-relevant genes and signalling pathways. RNA-sequencing data of a bone loading model were used to identify the loading-responsive gene set. Weighted gene co-expression network analysis (WGCNA) was employed to develop the osteocyte mechanics-responsive gene signature.

Results

A group of 77 persistent genes that are highly relevant to extracellular matrix (ECM) biology and bone remodelling signalling were identified in OA subchondral lesions. A loading responsive gene set, including 446 principal genes, was highly enriched in OA medial tibial plateaus compared to lateral tibial plateaus. Of this gene set, a total of 223 genes were identified as the main contributors that were strongly associated with osteocyte functions and signalling pathways, such as ECM modelling, axon guidance, Hippo, Wnt, and transforming growth factor beta (TGF-β) signalling pathways. We limited the loading-responsive genes obtained via the osteocyte transcriptome signature to identify a subgroup of genes that are highly relevant to osteocytes, as the mechanics-responsive osteocyte signature in OA. Based on WGCNA, we found that this signature was highly co-expressed and identified three clusters, including early, late, and persistently responsive genes.

Conclusion

In this study, we identified the mechanics-responsive osteocyte signature in OA-lesioned subchondral bone.

Cite this article: Bone Joint Res 2022;11(6):362–370.

Molecular signaling in temporomandibular joint osteoarthritis

Objective

Temporomandibular joint (TMJ) osteoarthritis (OA) is a type of TMJ disorders with clinical symptoms of pain, movement limitation, cartilage degeneration and joint dysfunction. This review article is aiming to summarize recent findings on signaling pathways involved in TMJ OA development and progression.

Methods

Most recent findings in TMJ OA studies have been reviewed and cited.

Results

TMJ OA is caused by inflammation, abnormal mechanical loading and genetic abnormalities. The molecular mechanisms related to TMJ OA have been determined using different genetic mouse models. Recent studies demonstrated that several signaling pathways are involved in TMJ OA pathology, including Wnt/β-catenin, TGF-β and BMP, Indian Hedgehog, FGF, NF-κB, and Notch pathways, which are summarized in this review article. Alterations of these signaling pathways lead to the pathological changes in TMJ tissues, affecting cartilage matrix degradation, catabolic metabolism and chondrocyte apoptosis.

Conclusion

Multiple signaling pathways were involved in the pathological process of TMJ OA. New therapeutic strategies, such as stem cell application, gene editing and other techniques may be utilized for TMJ OA treatment.

The translational potential of this article

TMJ OA is a most important subtype of TMJ disorders and may lead to substantial joint pain, dysfunction, dental malocclusion, and reduced health-related quality of life. This review article summarized current findings of signaling pathways involved in TMJ OA, including Wnt/β-catenin, TGF-β and BMP, Indian Hedgehog, FGF, NF-κB, and Notch pathways, to better understand the pathological mechanisms of TMJ OA and define the molecular targets for TMJ OA treatment.

Serum Periostin Level Reflects Progression of Ossification of the Posterior Longitudinal Ligament

Background:

Ossification of the posterior longitudinal ligament (OPLL), characterized by ectopic new bone formation in the spinal ligament, causes neurological impairment due to narrowing of the spinal canal. However, the etiology has not been fully elucidated yet. Several biomarkers may be related to the pathogenesis of OPLL. The present study focused on the serum level of periostin, which is recognized as an important bone formation regulator.

Methods:

This study included 92 patients with OPLL and 54 control patients without OPLL. For the case-control analysis, 54 age and sex-matched patients were randomly included in the OPLL group. The serum fibroblast growth factor-23 (FGF-23), creatinine, inorganic phosphate, calcium, alkaline phosphatase, and periostin levels were assessed. Furthermore, the calcium, creatinine, and inorganic phosphate levels in urine and the percentage of tubular reabsorption of phosphate were also analyzed. Moreover, the relationship between the biomarkers and the extent of OPLL was analyzed. The data were compared between patients with OPLL progression (the progression group) and without OPLL progression (the non-progression group).

Results:

The mean serum FGF-23 and periostin levels in the OPLL group were higher than that in the control group. The serum inorganic phosphate level in the OPLL group was lower than that in the control group. No correlation was found between any of the biomarkers and the extent of ossification. The serum periostin level in the progression group was higher than that in the non-progression group. No significant difference in the serum FGF-23 level was noted between the progression and non-progression groups. Moreover, no correlation was found between serum periostin and FGF-23 levels.

Conclusions:

The serum periostin level is related to OPLL progression.

Level of Evidence:

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Review of early circulating biomolecules associated with diabetes nephropathy - Ideal candidates for early biomarker array test for DN

BACKGROUND

Diabetic nephropathy (DN) is one of the catastrophic complications of type 2 diabetes mellitus (T2DM). 45% of DN patients progressed to End Stage Renal Disease (ESRD) which robs casualties of the quality of live. The challenge in early diagnosis of DN is it is asymptomatic in the early phase. Current gold standard test for screening and diagnosis of DN are nonspecific and are not sensitive in detecting DN early enough and subsequently monitor renal function during management and intervention plans. Recent studies reported various biomolecules which are associated with the onset of DN in T2DM using cutting-edge technologies. These biomolecules could be potential early biomarkers for DN. This review selectively identified potential early serum biomolecules which are potential candidates for developing an Early Biomarker Array Test for DN.

METHODS

An advanced literature search was conducted on 4 online databases. Search terms used were "Diabetes Mellitus, Type 2", "Diabetic nephropathy", "pathogenesis" and "early biomarker. Filters were applied to capture articles published from 2010 to 2020, written in English, human or animal models and focused on serum biomolecules associated with DN.

RESULTS

Five serum biomolecules have been evidently described as contributing pivotal roles in the pathophysiology of DN. MiR-377, miR-99b, CYP2E1, TGF-β1 and periostin are potential candidates for designing an early biomarker array for screening and diagnosis of early stages of DN. The five shortlisted biomolecules originates from endogenous biochemical processes which are specific to the progressive pathophysiology of DN.

CONCLUSION

miR-377, miR-99b, CYP2E1, TGF-β1 and periostin are potential candidate biomolecules for diagnosing DN at the early phases and can be developed into a panel of endogenous biomarkers for early detection of DN in patients with T2DM. The outcomes of this study will be a stepping stone towards planning and developing an early biomarker array test for diabetic nephropathy. The proposed panel of early biomarkers for DN has potential of stratifying the stages of DN because each biomolecule appears at distinct stages in the pathophysiology of DN.

Early detection of diabetic nephropathy in patient with type 2 diabetes mellitus: A review of the literature

Type 2 diabetes mellitus is a pathology of heterogeneous etiology characterized by hyperglycemia resulting from lack of insulin action, insulin secretion, or both, and the population with diabetes mellitus is predicted to be about 439 million worldwide by 2030. Prolong diabetes has been related with microvascular complications especially diabetic nephropathy. DN is the most common complication of type 2 diabetes mellitus, and it is the leading cause of end-stage renal disease worldwide. It is crucial to diagnose patients who are more sensible to develop DN for better control of the process of disease. Several factors and mechanisms contribute to the development and outcome of diabetic nephropathy. Microalbuminuria is an early marker of DN and use it as a routine for screening, but the renal damages may be happening even without microalbuminuria. There are several significant kidney damage and disease biomarkers which helps in early detection of DN. An early biomarker may allow earlier diagnosis, treatment reduces DN prevalence and slows DN progression. Therefore, this review focuses on laboratory biomarkers that are earlier, more validation of an early and specific biomarker could potentially make it possible for early diagnosis, treatment, and retardation of progression of diabetic nephropathy.

Periostin: An Emerging Molecule With a Potential Role in Spinal Degenerative Diseases

Periostin, an extracellular matrix protein, is widely expressed in a variety of tissues and cells. It has many biological functions and is related to many diseases: for example, it promotes cell proliferation and differentiation in osteoblasts, which are closely related to osteoporosis, and mediates cell senescence and apoptosis in chondrocytes, which are involved in osteoarthritis. Furthermore, it also plays an important role in mediating inflammation and reconstruction during bronchial asthma, as well as in promoting bone development, reconstruction, repair, and strength. Therefore, periostin has been explored as a potential biomarker for various diseases. Recently, periostin has also been found to be expressed in intervertebral disc cells as a component of the intervertebral extracellular matrix, and to play a crucial role in the maintenance and degeneration of intervertebral discs. This article reviews the biological role of periostin in bone marrow-derived mesenchymal stem cells, osteoblasts, osteoclasts, chondrocytes, and annulus fibrosus and nucleus pulposus cells, which are closely related to spinal degenerative diseases. The study of its pathophysiological effects is of great significance for the diagnosis and treatment of spinal degeneration, although additional studies are needed.

Periostin in Allergy and Inflammation

Matricellular proteins are involved in the crosstalk between cells and their environment and thus play an important role in allergic and inflammatory reactions. Periostin, a matricellular protein, has several documented and multi-faceted roles in health and disease. It is differentially expressed, usually upregulated, in allergic conditions, a variety of inflammatory diseases as well as in cancer and contributes to the development and progression of these diseases. Periostin has also been shown to influence tissue remodelling, fibrosis, regeneration and repair. In allergic reactions periostin is involved in type 2 immunity and can be induced by IL-4 and IL-13 in bronchial cells. A variety of different allergic diseases, among them bronchial asthma and atopic dermatitis (AD), have been shown to be connected to periostin expression. Periostin is commonly expressed in fibroblasts and acts on epithelial cells as well as fibroblasts involving integrin and NF-κB signalling. Also direct signalling between periostin and immune cells has been reported. The deposition of periostin in inflamed, often fibrotic, tissues is further fuelling the inflammatory process. There is increasing evidence that periostin is also expressed by epithelial cells in several of the above-mentioned conditions as well as in cancer. Augmented periostin expression has also been associated with chronic inflammation such as in inflammatory bowel disease (IBD). Periostin can be expressed in a variety of different isoforms, whose functions have not been elucidated yet. This review will discuss potential functions of periostin and its different isoforms in allergy and inflammation.

Vitamin K-Dependent Proteins in Skeletal Development and Disease

Vitamin K and Vitamin K-dependent proteins (VKDPs) are best known for their pivotal role in blood coagulation. Of the 14 VKPDs identified in humans to date, 6 play also important roles in skeletal biology and disease. Thus, osteocalcin, also termed bone Gla-protein, is the most abundant non-collagenous protein in bone. Matrix Gla protein and Ucma/GRP on the other hand are highly abundant in cartilage. Furthermore, periostin, protein S, and growth arrest specific 6 protein (GAS 6) are expressed in skeletal tissues. The roles for these VKDPs are diverse but include the control of calcification and turnover of bone and cartilage. Vitamin K plays an important role in osteoporosis and serum osteocalcin levels are recognized as a promising marker for osteoporosis. On the other hand, matrix Gla protein and Ucma/GRP are associated with osteoarthritis. This review focuses on the roles of these three VKDPs, osteocalcin, matrix Gla protein and Ucma/GRP, in skeletal development and disease but will also summarize the roles the other skeletal VKDPs (periostin, protein S and GAS6) in skeletal biology.

Osteocyte Dysfunction in Joint Homeostasis and Osteoarthritis

Structural disturbances of the subchondral bone are a hallmark of osteoarthritis (OA), including sclerotic changes, cystic lesions, and osteophyte formation. Osteocytes act as mechanosensory units for the micro-cracks in response to mechanical loading. Once stimulated, osteocytes initiate the reparative process by recruiting bone-resorbing cells and bone-forming cells to maintain bone homeostasis. Osteocyte-expressed sclerostin is known as a negative regulator of bone formation through Wnt signaling and the RANKL pathway. In this review, we will summarize current understandings of osteocytes at the crossroad of allometry and mechanobiology to exploit the relationship between osteocyte morphology and function in the context of joint aging and osteoarthritis. We also aimed to summarize the osteocyte dysfunction and its link with structural and functional disturbances of the osteoarthritic subchondral bone at the molecular level. Compared with normal bones, the osteoarthritic subchondral bone is characterized by a higher bone volume fraction, a larger trabecular bone number in the load-bearing region, and an increase in thickness of pre-existing trabeculae. This may relate to the aberrant expressions of sclerostin, periostin, dentin matrix protein 1, matrix extracellular phosphoglycoprotein, insulin-like growth factor 1, and transforming growth factor-beta, among others. The number of osteocyte lacunae embedded in OA bone is also significantly higher, yet the volume of individual lacuna is relatively smaller, which could suggest abnormal metabolism in association with allometry. The remarkably lower percentage of sclerostin-positive osteocytes, together with clustering of Runx-2 positive pre-osteoblasts, may suggest altered regulation of osteoblast differentiation and osteoblast-osteocyte transformation affected by both signaling molecules and the extracellular matrix. Aberrant osteocyte morphology and function, along with anomalies in molecular signaling mechanisms, might explain in part, if not all, the pre-osteoblast clustering and the uncoupled bone remodeling in OA subchondral bone.

Intra-articular silencing of periostin via nanoparticle-based siRNA ameliorates post-traumatic osteoarthritis in mice

OBJECTIVE

Recent evidence delineates an emerging role of Periostin (Postn) in osteoarthritis (OA) as its expression subsequent to knee injury is detrimental to the articular cartilage. We hypothesize that intra-articular knockdown of Postn in a murine model of post-traumatic OA would ameliorate OA.

METHODS

Post-traumatic OA was induced in 10-week-old male C57BL/6J mice (n=24) by destabilization of the medial meniscus (DMM) and analyzed 8-week post-surgery. Intra-articular Postn was inhibited by siRNA using a novel peptide-nucleotide polyplex. Cartilage degeneration (OARSI score) and synovitis were assessed histologically. Bone changes were measured by μCT. The effect and mechanism of Postn silencing were investigated in human chondrocytes treated with IL-1β with or without IKK2 inhibitor, SC-514.

RESULTS

Peptide-siRNA nanoplatform significantly abolished Postn expression. OARSI score was significantly less in mice receiving Postn siRNA (10.94±0.66) compared to both untreated (22.38±1.30,P=0.002) and scrambled siRNA (22.69±0.87,P=0.002) treatment. No differences were observed in synovitis. Subchondral bone sclerosis, BV/TV, vBMD, and heterotopic ossification were significantly low in Postn siRNA treatment. Immunostaining of cartilage revealed that Postn knockdown reduced the DMM-induced MMP-13 intensity, phosphorylation of p65, and immunoreactivity of aggrecan neoepitope, DIPEN. Postn knockdown also suppressed IL-1β-induced MMP-13 and ADAMTS-4 in chondrocytes. Mechanistically, Postn-induced MMP-13 was abrogated by SC-514 demonstrating a link between Postn and NF-κB.

CONCLUSION

Intra-articular delivery of Postn siRNA nanocomplex represents a promising clinical approach to mitigate the severity of joint degeneration and provides an unequivocal scientific rationale for longitudinal studies. Employing a cartilage-specific gene knockout strategy will further illuminate the functional role of Postn in OA.

Periostin Short Fragment with Exon 17 via Aberrant Alternative Splicing Is Required for Breast Cancer Growth and Metastasis

BACKGROUND

Periostin (POSTN) is a 93 kDa matrix protein that helps to regulate collagen gene expression in the extracellular matrix. POSTN overexpression is a prognostic factor in malignant cancers; however, some researchers have observed it in the stroma, whereas others have reported it on tumors.

OBJECTIVE

This study aimed to investigate the function of POSTN on tumors.

METHODS AND RESULTS

We found that POSTN in cancer cells can be detected by using an antibody against the POSTN C-terminal region exon 17 (Ex17 antibody), but not with an antibody against the POSTN N-terminal region exon 12 (Ex12 antibody) in patients with breast cancer. In a fraction secreted from fibroblasts, LC-MS/MS analysis revealed a short fragment of POSTN of approximately 40 kDa with exon 17. In addition, molecular interaction analysis showed that POSTN with exon 17, but not POSTN without exon 17, bound specifically to wnt3a, and the Ex17 antibody inhibited the binding.

CONCLUSION

A short fragment of POSTN with exon 17, which originates in the fibroblasts, is transported to cancer cells, whereas POSTN fragments without exon 17 are retained in the stroma. The Ex17 antibody inhibits the binding between POSTN exon 17 and wnt3a.

Periostin loss-of-function protects mice from post-traumatic and age-related osteoarthritis

Background

Elevated levels of periostin (Postn) in the cartilage and bone are associated with osteoarthritis (OA). However, it remains unknown whether Postn loss-of-function can delay or prevent the development of OA. In this study, we sought to better understand the role of Postn in OA development and assessed the functional impact of Postn deficiency on post-traumatic and age-related OA in mice.

Methods

The effects of Postn deficiency were studied in two murine experimental OA models using Postn^−/− (n = 32) and littermate wild-type (wt) mice (n = 36). Post-traumatic OA was induced by destabilization of the medial meniscus (DMM) in 10-week-old mice (n = 20); age-related OA was analyzed in 24-month-old mice (n = 13). Cartilage degeneration was assessed histologically using the OARSI scoring system, and synovitis was evaluated by measuring the synovial lining cell layer and the cells density in the synovial stroma. Bone changes were measured by μCT analysis. Serum levels of Postn were determined by ELISA. Expression of Postn and collagenase-3 (MMP-13) was measured by immunostaining. RNA-seq was performed on chondrocytes isolated from 21-day old Postn^−/− (n = 3) and wt mice (n = 3) to discover genes and pathways altered by Postn knockout.

Results

Postn^−/− mice exhibited significantly reduced cartilage degeneration and OARSI score relative to wt mice in post-traumatic OA after 8 weeks (maximum: 2.37 ± 0.74 vs. 4.00 ± 1.20, P = 0.011; summed: 9.31 ± 2.52 vs. 21.44 ± 6.01, P = 0.0002) and spontaneous OA (maximum: 1.93 ± 0.45 vs. 3.58 ± 1.16, P = 0.014; summed: 6.14 ± 1.57 vs. 11.50 ± 3.02, P = 0.003). Synovitis was significantly lower in Postn^−/− mice than wt only in the DMM model (1.88 ± 1.01 vs. 3.17 ± 0.63; P = 0.039). Postn^−/− mice also showed lower trabecular bone parameters such as BV/TV, vBMD, Tb.Th, and Tb.N and high Tb. Sp in both models. Postn^−/− mice had negligible levels of serum Postn compared with wt. Immunofluorescent studies of cartilage indicated that Postn^−/− mice expressed lower MMP-13 levels than wt mice. RNA-seq revealed that cell-cell-adhesion and cell-differentiation processes were enriched in Postn^−/− mice, while those related to cell-cycle and DNA-repair were enriched in wt mice.

Conclusions

Postn deficiency protects against DMM-induced post-traumatic and age-related spontaneous OA. RNA-seq findings warrant further investigations to better understand the mechanistic role of Postn and its potential as a therapeutic target in OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02477-z.

Periostin Mediates Condylar Resorption via the NF-κB-ADAMTS5 Pathway

Although the up-regulation of periostin in osteoarthritic (OA) is found, its function on OA condyle caused by disc displacement is not clear. Our objective was to explore whether periostin has any effect on condylar resorption. We initially identified periostin-positive cells in temporomandibular joint osteoarthritic (TMJ-OA) cartilage. Furthermore, the vitro analysis confirmed that the expression of periostin in chondrocytes treated with a static pressure of 150 kpa and 200 kpa for 3 h by an in-house-designed pressure chamber. To explore the underlying mechanism, we found that periostin can induce IκBα phosphorylation and its subsequent degradation, leading to consequent p65 nuclear translocation and subsequent induction of ADAMTS5 expression, which is known to be detrimental to cartilage extracellular matrix production. Importantly, inhibiting NF-κB signaling, by BAY 11-7082 treatment, rescued periostin-induced ADAMTS5 up-regulation. This study elucidated the direct role of periostin in condylar resorption, which was found to occur via NF-κB-ADAMTS5 signaling. Inhibition of this pathway might provide a new strategy for TMJ-OA treatment.

Preventive Effect of the Japanese Traditional Herbal Medicine Boiogito on Posttraumatic Osteoarthritis in Rats

Background: Considering the anti-inflammatory properties of the Japanese traditional Kampo medicine Boiogito (BO), we aimed to investigate the therapeutic effect of BO to prevent the development of knee osteoarthritis (KOA) in rats with surgically induced KOA. Methods: Destabilization of the medial meniscus (DMM) was performed to induce osteoarthritis in the right knees of 12-week-old Wistar rats under general anesthesia. The rats were orally administered 3% BO in standard powder chow for 4 weeks after surgery (controls: n = 6; sham group: n = 6; DMM group: n = 5; DMM + BO group: n = 5). During this period, the rotarod test was performed to monitor locomotive function. After 4 weeks, histological assessment was performed on the right knee. Results: Oral administration of BO improved locomotive function in the rotarod test. Walking time on postoperative days 1, 14, or later was significantly longer in the DMM + BO group than in the DMM group. Histologically, the DMM group showed significant progression of KOA, which, in the DMM + BO group, was strongly suppressed, as assessed by the Osteoarthritis Research Society International score. Conclusions: Our results showed that oral administration of BO had a clinically preventive effect on early stage posttraumatic KOA.

The effect of non-surgical periodontal treatment on gingival crevicular fluid periostin levels in patients with gingivitis and periodontitis

OBJECTIVE

The objective of the study was to evaluate the effect of non-surgical periodontal treatment on gingival crevicular fluid (GCF) periostin levels in patients with gingivitis (G) and periodontitis (P).

SUBJECTS AND METHODS

A total of 90 subjects, 30 patients with P, 30 with G, and 30 periodontally healthy (H) subjects were included. Patients with periodontal disease received non-surgical periodontal treatment. GCF periostin levels were assessed at baseline, at the 6th week, and the 3rd month after treatment.

RESULTS

It was found that GCF periostin level was the lowest in the H group (89.31[47.12] pg/30 sec), followed by the G group (132.82[145.14] pg/30 sec), and the highest in the P group (207.75[189.45] pg/30 sec). These differences were statistically significant between H and the other groups (p < .001). After treatment, GCF periostin levels significantly decreased at the 6th week and the 3rd month in the G group, at the 3rd month in the P group compared to baseline values (p < .05).

CONCLUSION

The results of this study suggest that GCF periostin plays a role as a reliable biological marker in the pathogenesis of periodontal disease and non-surgical periodontal treatment is effective in decreasing GCF periostin levels.

Perlecan Knockdown Significantly Alters Extracellular Matrix Composition and Organization During Cartilage Development

Perlecan is a critical proteoglycan found in the extracellular matrix (ECM) of cartilage. In healthy cartilage, perlecan regulates cartilage biomechanics and we previously demonstrated perlecan deficiency leads to reduced cellular and ECM stiffness in vivo This change in mechanics may lead to the early onset osteoarthritis seen in disorders resulting from perlecan knockdown such as Schwartz-Jampel syndrome (SJS). To identify how perlecan knockdown affects the material properties of developing cartilage, we used imaging and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to study the ECM in a murine model of SJS, Hspg2C1532Y-Neo Perlecan knockdown led to defective pericellular matrix formation, whereas the abundance of bulk ECM proteins, including many collagens, increased. Post-translational modifications and ultrastructure of collagens were not significantly different; however, LC-MS/MS analysis showed more protein was secreted by Hspg2C1532Y-Neo cartilage in vitro, suggesting that the incorporation of newly synthesized ECM was impaired. In addition, glycosaminoglycan deposition was atypical, which may explain the previously observed decrease in mechanics. Overall, these findings provide insight into the influence of perlecan on functional cartilage assembly and the progression of osteoarthritis in SJS.

Periostin interaction with discoidin domain receptor-1 (DDR1) promotes cartilage degeneration

Osteoarthritis (OA) is characterized by progressive loss of articular cartilage accompanied by the new bone formation and, often, a synovial proliferation that culminates in pain, loss of joint function, and disability. However, the cellular and molecular mechanisms of OA progression and the relative contributions of cartilage, bone, and synovium remain unclear. We recently found that the extracellular matrix (ECM) protein periostin (Postn, or osteoblast-specific factor, OSF-2) is expressed at high levels in human OA cartilage. Multiple groups have also reported elevated expression of Postn in several rodent models of OA. We have previously reported that in vitro Postn promotes collagen and proteoglycan degradation in human chondrocytes through AKT/β-catenin signaling and downstream activation of MMP-13 and ADAMTS4 expression. Here we show that Postn induces collagen and proteoglycan degradation in cartilage by signaling through discoidin domain receptor-1 (DDR1), a receptor tyrosine kinase. The genetic deficiency or pharmacological inhibition of DDR1 in mouse chondrocytes blocks Postn-induced MMP-13 expression. These data show that Postn is signaling though DDR1 is mechanistically involved in OA pathophysiology. Specific inhibitors of DDR1 may provide therapeutic opportunities to treat OA.

Proteomic analysis of synovial fluid identifies periostin as a biomarker for anterior cruciate ligament injury

OBJECTIVE

Emerging evidence suggests that injury to the anterior cruciate ligament (ACL) typically initiates biological changes that contribute to the development of osteoarthritis (OA). The molecular biomarkers or mediators of these biological events remain unknown. The goal of this exploratory study was to identify novel synovial fluid biomarkers associated with early biological changes following ACL injury distinct from findings in end-stage OA.

METHODS

Synovial fluid was aspirated from patients with acute (≤30 days) and subacute (31-90 days) ACL tears and from patients with advanced OA and probed via tandem mass spectrometry for biomarkers to distinguish OA from ACL injury. Periostin (POSTN) was identified as a potential candidate. Further analyses of POSTN were performed in synovial fluid, OA cartilage, torn ACL remnants, and cultured cells and media by Western blot, PCR, immunostaining and ELISA.

RESULTS

Synovial fluid analysis revealed that POSTN exhibited higher expression in subacute ACL injury than OA. POSTN expression was relatively low in cartilage/chondrocytes suggesting it is also produced by other intra-articular tissues. Conversely, high and time-dependent expression of POSTN in ACL tear remnants and isolated cells was consistent with the synovial fluid results.

CONCLUSIONS

Elevated POSTN may provide a synovial fluid biomarker of subacute ACL injury setting separate from OA. Increased expression of POSTN in ACL suggests that the injured ACL may play a pivotal role in POSTN production, which is sensitive to time from injury. Previous studies have shown potential catabolic effects of POSTN, raising the possibility that POSTN contributes to the initiation of joint degeneration and may offer a window of opportunity to intervene in the early stages of post-traumatic OA.

NF-κB Signaling Pathways in Osteoarthritic Cartilage Destruction

Osteoarthritis (OA) is a type of joint disease associated with wear and tear, inflammation, and aging. Mechanical stress along with synovial inflammation promotes the degradation of the extracellular matrix in the cartilage, leading to the breakdown of joint cartilage. The nuclear factor-kappaB (NF-κB) transcription factor has long been recognized as a disease-contributing factor and, thus, has become a therapeutic target for OA. Because NF-κB is a versatile and multi-functional transcription factor involved in various biological processes, a comprehensive understanding of the functions or regulation of NF-κB in the OA pathology will aid in the development of targeted therapeutic strategies to protect the cartilage from OA damage and reduce the risk of potential side-effects. In this review, we discuss the roles of NF-κB in OA chondrocytes and related signaling pathways, including recent findings, to better understand pathological cartilage remodeling and provide potential therapeutic targets that can interfere with NF-κB signaling for OA treatment.

E-cadherin and periostin in early detection and progression of diabetic nephropathy: epithelial-to-mesenchymal transition

BACKGROUND

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus (DM). Many mechanisms are involved in its development; one of these mechanisms is epithelial-to-mesenchymal transition (EMT). During EMT, losing of the epithelial biomarkers like E-cadherin and increasing of mesenchymal biomarkers like periostin are very characteristic.

METHODS

The study included 19 healthy controls and 71 DN patients categorized according to their urinary albumin-to-creatinine ratio (UACR) into 19 normoalbuminuric (UACR < 30 mg/g), 37 microalbuminuric (UACR 30-300 mg/g), and 15 macroalbuminuric (UACR > 300 mg/g) patients. Fasting plasma glucose (FPG), glycated hemoglobin (HbA_1C%), serum creatinine (Cr), and urea were measured. E-cadherin and periostin were measured by ELISA and compared among groups.

RESULTS

Concerning E-cadherin levels, in comparison to control group, there were significantly decreased in all groups (0.94, 0.52, and 0.14 ng/mL in normoalbuminuria, microalbuminuria, and macroalbuminuria groups; respectively). For periostin levels, nonsignificant increase in normoalbuminuria (0.32 ng/mL) than control group (0.3 ng/mL) was observed. There was a significant increase in other groups with the highest values in macroalbuminuria group (1.66 ng/mL). E-cadherin and periostin were correlated with each other (r = - 0.353, P < 0.001). UACR was negatively correlated with E-cadherin and positively correlated with periostin. ROC curve analyses showed that the AUC to diagnose established microalbuminuria using E-cadherin was 0.998 (95% CI 0. 932-1), and using periostin was 0.833 (95% CI 0.709-0.919).

CONCLUSION

Serum E-cadherin and periostin could be considered as reliable biomarkers involved in DN pathogenesis and linked to its stages.

Distinct expression pattern of periostin splice variants in chondrocytes and ligament progenitor cells

Periostin (POSTN), a secretory matricellular matrix protein, plays a multitude of biologic functions. Various splice variants of POSTN have been described; however, their expression pattern and functional implications are not completely understood. This study was undertaken to decipher the differential expression pattern of POSTN and its splice variants in various tissues and cell types. We show that POSTN was more highly expressed in anterior cruciate ligament (ACL) remnants compared with articular cartilage at the cellular and tissue level. Isoforms 1 and 8 were highly expressed only in articular chondrocytes, suggesting their splice-specific regulation in chondrocytes. To discern the role of total POSTN and full-length human POSTN isoform 1 (hPOSTN-001), we stably transfected human chondrosarcoma 1 (hCh-1) cell line with hPOSTN-001 using a pcDNA3.1-hPOSTN-001 construct. RNA-sequencing analysis of hCh-1 cells identified differentially expressed genes with a known role in chondrocyte function and osteoarthritis. Similar expression of a subset of candidate genes was revealed in ACL progenitor cells and chondrocytes as well as in ACL progenitor cells in which POSTN activity was altered by overexpression and by small interfering RNA gene knockdown. Cells expressing total POSTN, not isoform 1, exhibited increased cell adhesion potential. These findings suggest an important role for POSTN in the knee.-Cai, L., Brophy, R. H., Tycksen, E. D., Duan, X., Nunley, R. M., Rai, M. F. Distinct expression pattern of periostin splice variants in chondrocytes and ligament progenitor cells.

CEMIP (KIAA1199) induces a fibrosis-like process in osteoarthritic chondrocytes

CEMIP (for "Cell migration-inducing protein" also called KIAA1199 and Hybid for "Hyaluronan-binding protein") expression is increased in cancers and described as a regulator of cell survival, growth and invasion. In rheumatoid arthritis, CEMIP is referred to as an angiogenic marker and participates in hyaluronic acid degradation. In this study, CEMIP expression is investigated in healthy and osteoarthritis (OA) cartilage from human and mouse. Its role in OA physiopathology is deciphered, specifically in chondrocytes proliferation and dedifferentiation and in the extracellular matrix remodeling. To this end, CEMIP, αSMA and types I and III collagen expressions were assessed in human OA and non-OA cartilage. CEMIP expression was also investigated in a mouse OA model. CEMIP expression was studied in vitro using a chondrocyte dedifferentiation model. High-throughput RNA sequencing was performed on chondrocytes after CEMIP silencing. Results showed that CEMIP was overexpressed in human and murine OA cartilage and along chondrocytes dedifferentiation. Most of genes deregulated in CEMIP-depleted cells were involved in cartilage turnover (e.g., collagens), mesenchymal transition and fibrosis. CEMIP regulated β-catenin protein level. Moreover, CEMIP was essential for chondrocytes proliferation and promoted αSMA expression, a fibrosis marker, and TGFβ signaling towards the p-Smad2/3 (Alk5/PAI-1) pathway. Interestingly, CEMIP was induced by the pSmad1/5 (Alk1) pathway. αSMA and type III collagen expressions were overexpressed in human OA cartilage and along chondrocytes dedifferentiation. Finally, CEMIP was co-expressed in situ with αSMA in all OA cartilage layers. In conclusion, CEMIP was sharply overexpressed in human and mouse OA cartilage and along chondrocytes dedifferentiation. CEMIP-regulated transdifferentiation of chondrocytes into "chondro-myo-fibroblasts" expressing α-SMA and type III collagen, two fibrosis markers. Moreover, these "chondro-myo-fibroblasts" were found in OA cartilage but not in healthy cartilage.

Protective effects of quercetin against inflammation and oxidative stress in a rabbit model of knee osteoarthritis

Hit, Lead & Candidate Discovery This study investigated the effects of a natural phenolic compound quercetin on surgical-induced osteoarthritis (OA) in rabbits. Forty-eight New Zealand White rabbits were used to establish OA model by Hulth modified method, and subsequently randomized into untreated OA group (treatment was drinking water), celecoxib treated group (celecoxib 100 mg kg^-1 by gavage), and quercetin treated group (25 mg kg^-1 by gavage). Sixteen nonoperated rabbits served as the normal controls (drinking water was given). The treatment (length: 4 weeks) started on the 5th week postoperation when the OA pathological changes were manifested. Expressions of superoxide dismutase (SOD), matrix metalloproteinase-13 (MMP-13) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in serum, synovial fluid, and synovial tissue were measured at 8 and 12 weeks postoperation. Pathological analysis was performed with synovial tissue section and Osteoarthritis Research Society International histopathology grading and staging scores were determined. The quercetin treated group showed higher SOD and TIMP-1 expressions but lower MMP-13 expression than untreated OA group in the serum, synovial fluid and synovial tissues (p < .05). There was no significant difference in the SOD, MMP-13 and TIMP-1 expressions between the quercetin-treated and celecoxib-treated groups. The MMP-13/TIMP-1 ratio of the quercetin treated group was significantly lower than that of the untreated OA group (p < .05). Quercetin can up-regulate SOD and TIMP-1, down-regulate MMP-13, and improve the degeneration of OA through weakening the oxidative stress responses and inhibiting the degradation of cartilage extracellular matrix.

Periostin in Bone Biology

Periostin is specifically expressed in periosteum that functions in bone modeling and remodeling and bone repair, and is sensitive to mechanical stress. Thus periostin has been expected for controlling these crucial systems in bone. The results from periostin deficient mice demonstrate that periostin acts on bone remodeling though detailed mechanisms are unknown. Recent findings have revealed that periostin is essential for bone repair. In this chapter, I introduce expression and function of periostin in bone.

Periostin Mediates Right Ventricular Failure through Induction of Inducible Nitric Oxide Synthase Expression in Right Ventricular Fibroblasts from Monocrotaline-Induced Pulmonary Arterial Hypertensive Rats

Pulmonary arterial hypertension (PAH) leads to lethal right ventricular failure (RVF). Periostin (POSTN) mRNA expression is increased in right ventricles (RVs) of monocrotaline (MCT)-induced PAH model rats. However, the pathophysiological role of POSTN in RVF has not been clarified. We investigated the effects of POSTN on inducible nitric oxide (NO) synthase (iNOS) expression and NO production, which causes cardiac dysfunction, in right ventricular fibroblasts (RVFbs). Male Wistar rats were intraperitoneally injected with MCT (60 mg/kg) or saline. Three weeks after injection, RVFbs were isolated from RVs of MCT- or saline-injected rats (MCT-RVFb or CONT-RVFb). In MCT-RVFb, iNOS expression and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and nuclear factor-kappa B (NF-κB) were higher than those in CONT-RVFb. Recombinant POSTN increased iNOS expression and NO production, which were prevented by a pharmacological inhibition of ERK1/2, JNK or NF-κB in RVFbs isolated from normal rats. Culture medium of POSTN-stimulated RVFbs suppressed Ca²⁺ inflow through l-type Ca²⁺ channel (LTCC) in H9c2 cardiomyoblasts. We demonstrated that POSTN enhances iNOS expression and subsequent NO production via ERK1/2, JNK, and NF-κB signaling pathways in RVFbs. POSTN might mediate RVF through the suppression of LTCC activity of cardiomyocytes by producing NO from RVFbs in PAH model rats.

Dose-Dependent Effect of Mesenchymal Stromal Cell Recruiting Chemokine CCL25 on Porcine Tissue-Engineered Healthy and Osteoarthritic Cartilage

Thymus-expressed chemokine (CCL25) is a potent cell attractant for mesenchymal stromal cells, and therefore it is a candidate for in situ cartilage repair approaches focusing on the recruitment of endogenous repair cells. However, the influence of CCL25 on cartilage is unknown. Accordingly, in this study, we investigated the effect of CCL25 on tissue-engineered healthy and osteoarthritic cartilage. Porcine chondrocytes were cultured in a three-dimensional (3D) micromass model that has been proven to mimic key-aspects of human cartilage and osteoarthritic alterations upon stimulation with tumor necrosis factor-α (TNF-α). Micromass cultures were stimulated with CCL25 (0, 0.05, 0.5, 5, 50, 500 nmol/L) alone or in combination with 0.6 nmol/L TNF-α for seven days. Effects were evaluated by life/dead staining, safranin O staining, histomorphometrical analysis of glycosaminoglycans (GAGs), collagen type II (COL2A1) real-time RT-PCR and Porcine Genome Array analysis. 500 nmol/L CCL25 led to a significant reduction of GAGs and COL2A1 expression and induced the expression of matrix metallopeptidases (MMP) 1, MMP3, early growth response protein 1 (EGR1), and superoxide dismutase 2 (SOD2). In concentrations lower than 500 nmol/L, CCL25 seems to be a candidate for in situ cartilage repair therapy approaches.

Molecular influence of anterior cruciate ligament tear remnants on chondrocytes: a biologic connection between injury and osteoarthritis

OBJECTIVE

Anterior cruciate ligament (ACL) injury initiates a cascade of events often leading to osteoarthritis (OA). ACL reconstruction does not alter the course of OA, suggesting that heightened OA risk is likely due to factors in addition to the joint instability. We showed that torn ACL remnants express periostin (POSTN) in the acute phase of injury. Considering that ACL injury predisposes to OA and that POSTN is associated with cartilage metabolism, we hypothesize that ACL injury affects chondrocytes via POSTN.

DESIGN

Cartilage was obtained from osteoarthritic patients and ACL remnants were collected from patients undergoing ACL reconstruction. Crosstalk between ACL remnants and chondrocytes was studied in a transwell co-culture system. Expression of POSTN and other anabolic and catabolic genes was assessed via real-time polymerase chain reaction (PCR). Immunostaining for periostin was performed in human and mouse cartilage. The impact of exogenous periostin and siRNA-mediated ablation of periostin on matrix metabolism and cell migration was examined. Furthermore, the effect of anabolic (transforming growth factor beta 1 [TGF-β1]) and catabolic (interleukin 1 beta [IL-1β]) factors on POSTN expression was investigated.

RESULTS

ACL remnants induced expression of POSTN, MMP13 and ADAMTS4. Periostin levels were significantly higher in osteoarthritic compared to normal cartilage. Exogenous periostin induced MMP13 expression and cell migration, and repressed COL1A1 expression while POSTN knockdown inhibited expression of both anabolic and catabolic genes and impeded cell migration. TGF-β1 and IL-1β treatment did not alter POSTN expression but influenced chondrocyte metabolism as determined by quantification of anabolic and catabolic genes via real-time PCR.

CONCLUSIONS

ACL remnants can exert paracrine effects on cartilage, altering cellular homeostasis. Over time, this metabolic imbalance could contribute to OA development.

Transcriptome comparison of meniscus from patients with and without osteoarthritis

OBJECTIVE

To assess the impact of osteoarthritis (OA) on the meniscus by comparing transcripts and biological processes in the meniscus between patients with and without OA.

DESIGN

RNA microarrays were used to identify transcripts differentially expressed (DE) in meniscus obtained from 12 OA and 12 non-OA patients. The non-OA specimens were obtained at the time of arthroscopic partial meniscectomy. Real-time PCR was performed on selected transcripts. Biological processes and gene-networking was examined computationally. Transcriptome signatures were mapped with 37 OA-related transcripts to evaluate how meniscus gene expression relates to that of OA cartilage.

RESULTS

We identified 168 transcripts significantly DE between OA (75 elevated, 93 repressed) and non-OA samples (≥1.5-fold). Among these, CSN1S1, COL10A1, WIF1, and SPARCL1 were the most prominent transcripts elevated in OA meniscus, POSTN and VEGFA were most highly repressed in OA meniscus. Transcripts elevated in OA meniscus represented response to external stimuli, cell migration and cell localization while those repressed in OA meniscus represented histone deacetylase activity (related to epigenetics) and skeletal development. Numerous long non-coding RNAs (lncRNAs) were DE between the two groups. When segregated by OA-related transcripts, two distinct clustering patterns appeared: OA meniscus appeared to be more inflammatory while non-OA meniscus exhibited a "repair" phenotype.

CONCLUSIONS

Numerous transcripts with potential relevance to the pathogenesis of OA are DE in OA and non-OA meniscus. These data suggest an involvement of epigenetically regulated histone deacetylation in meniscus tears as well as expression of lncRNAs. Patient clustering based on transcripts related to OA in articular cartilage confirmed distinct phenotypes between injured (non-OA) and OA meniscus.

Advantages of RNA-seq compared to RNA microarrays for transcriptome profiling of anterior cruciate ligament tears

Microarrays and RNA-seq are at the forefront of high throughput transcriptome analyses. Since these methodologies are based on different principles, there are concerns about the concordance of data between the two techniques. The concordance of RNA-seq and microarrays for genome-wide analysis of differential gene expression has not been rigorously assessed in clinically derived ligament tissues. To demonstrate the concordance between RNA-seq and microarrays and to assess potential benefits of RNA-seq over microarrays, we assessed differences in transcript expression in anterior cruciate ligament (ACL) tissues based on time-from-injury. ACL remnants were collected from patients with an ACL tear at the time of ACL reconstruction. RNA prepared from torn ACL remnants was subjected to Agilent microarrays (N = 24) and RNA-seq (N = 8). The correlation of biological replicates in RNA-seq and microarrays data was similar (0.98 vs. 0.97), demonstrating that each platform has high internal reproducibility. Correlations between the RNA-seq data and the individual microarrays were low, but correlations between the RNA-seq values and the geometric mean of the microarrays values were moderate. The cross-platform concordance for differentially expressed transcripts or enriched pathways was linearly correlated (r = 0.64). RNA-Seq was superior in detecting low abundance transcripts and differentiating biologically critical isoforms. Additional independent validation of transcript expression was undertaken using microfluidic PCR for selected genes. PCR data showed 100% concordance (in expression pattern) with RNA-seq and microarrays data. These findings demonstrate that RNA-seq has advantages over microarrays for transcriptome profiling of ligament tissues when available and affordable. Furthermore, these findings are likely transferable to other musculoskeletal tissues where tissue collection is challenging and cells are in low abundance. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:484-497, 2018.

Do immune cells lead the way in subchondral bone disturbance in osteoarthritis?

Osteoarthritis (OA) is a whole-joint disorder, and non-cartilage articular pathologies, e.g. subchondral bone disturbance, contribute substantially to the onset and progression of the disease. In the early stage of OA, abnormal mechanical loading leads to micro-cracks or micro-fractures that trigger a reparative process with angiogenesis and inflammatory response. With the progression of disease, cystic lesion, sclerosis and osteophytosis occur at tissue level, and osteoblast dysfunction at cellular level. Osteoblasts derived from OA sclerotic bone produce increased amount of type I collagen with aberrant Col1A1/A2 ratio and poor mineralization capability. The coupling mechanism of bone resorption with formation is also impaired with elevated osteoclastic activities. All these suggest a view that OA subchondral bone presents a defective fracture repair process in a chronic course. It has been found that T and B cells, the major effectors in the adaptive immunity, take part in the hard callus formation at fracture site in addition to the initial phase of haematoma and inflammation. Infiltration of lymphocytes could interplay with osteoclasts and osteoblasts via a direct physical cell-to-cell contact. Several lines of evidence have consistently shown the involvement of T and B cells in osteoclastogenesis and bone erosion in arthritic joints. Yet the biological link between immune cells and osteoblastic function remains ambiguous. This review will discuss the current knowledge regarding the role of immune cells in bone remodelling, and address its implications in emerging basic and clinical investigations into the pathogenesis and management of subchondral bone pathologies in OA.

Hypoxia and Redox Signaling on Extracellular Matrix Remodeling: From Mechanisms to Pathological Implications

SIGNIFICANCE

The extracellular matrix (ECM) is an essential modulator of cell behavior that influences tissue organization. It has a strong relevance in homeostasis and translational implications for human disease. In addition to ECM structural proteins, matricellular proteins are important regulators of the ECM that are involved in a myriad of different pathologies. Recent Advances: Biochemical studies, animal models, and study of human diseases have contributed to the knowledge of molecular mechanisms involved in remodeling of the ECM, both in homeostasis and disease. Some of them might help in the development of new therapeutic strategies. This review aims to review what is known about some of the most studied matricellular proteins and their regulation by hypoxia and redox signaling, as well as the pathological implications of such regulation.

CRITICAL ISSUES

Matricellular proteins have complex regulatory functions and are modulated by hypoxia and redox signaling through diverse mechanisms, in some cases with controversial effects that can be cell or tissue specific and context dependent. Therefore, a better understanding of these regulatory processes would be of great benefit and will open new avenues of considerable therapeutic potential.

FUTURE DIRECTIONS

Characterizing the specific molecular mechanisms that modulate matricellular proteins in pathological processes that involve hypoxia and redox signaling warrants additional consideration to harness the potential therapeutic value of these regulatory proteins. Antioxid. Redox Signal. 27, 802-822.

Integrative epigenomics, transcriptomics and proteomics of patient chondrocytes reveal genes and pathways involved in osteoarthritis

Osteoarthritis (OA) is a common disease characterized by cartilage degeneration and joint remodeling. The underlying molecular changes underpinning disease progression are incompletely understood. We investigated genes and pathways that mark OA progression in isolated primary chondrocytes taken from paired intact versus degraded articular cartilage samples across 38 patients undergoing joint replacement surgery (discovery cohort: 12 knee OA, replication cohorts: 17 knee OA, 9 hip OA patients). We combined genome-wide DNA methylation, RNA sequencing, and quantitative proteomics data. We identified 49 genes differentially regulated between intact and degraded cartilage in at least two -omics levels, 16 of which have not previously been implicated in OA progression. Integrated pathway analysis implicated the involvement of extracellular matrix degradation, collagen catabolism and angiogenesis in disease progression. Using independent replication datasets, we showed that the direction of change is consistent for over 90% of differentially expressed genes and differentially methylated CpG probes. AQP1, COL1A1 and CLEC3B were significantly differentially regulated across all three -omics levels, confirming their differential expression in human disease. Through integration of genome-wide methylation, gene and protein expression data in human primary chondrocytes, we identified consistent molecular players in OA progression that replicated across independent datasets and that have translational potential.