And Metalloproteinase With Thrombospondin Motifs Research Articles

Expression and Activity of TRPA1 and TRPV1 in the Intervertebral Disc: Association with Inflammation and Matrix Remodeling.

Transient receptor potential (TRP) channels have emerged as potential sensors and transducers of inflammatory pain. The aims of this study were to investigate (1) the expression of TRP channels in intervertebral disc (IVD) cells in normal and inflammatory conditions and (2) the function of Transient receptor potential ankyrin 1 (TRPA1) and Transient receptor potential vanilloid 1 (TRPV1) in IVD inflammation and matrix homeostasis. RT-qPCR was used to analyze human fetal, healthy, and degenerated IVD tissues for the gene expression of TRPA1 and TRPV1. The primary IVD cell cultures were stimulated with either interleukin-1 beta (IL-1β) or tumor necrosis factor alpha (TNF-α) alone or in combination with TRPA1/V1 agonist allyl isothiocyanate (AITC, 3 and 10 µM), followed by analysis of calcium flux and the expression of inflammation mediators (RT-qPCR/ELISA) and matrix constituents (RT-qPCR). The matrix structure and composition in caudal motion segments from TRPA1 and TRPV1 wild-type (WT) and knock-out (KO) mice was visualized by FAST staining. Gene expression of other TRP channels (A1, C1, C3, C6, V1, V2, V4, V6, M2, M7, M8) was also tested in cytokine-treated cells. TRPA1 was expressed in fetal IVD cells, 20% of degenerated IVDs, but not in healthy mature IVDs. TRPA1 expression was not detectable in untreated cells and it increased upon cytokine treatment, while TRPV1 was expressed and concomitantly reduced. In inflamed IVD cells, 10 µM AITC activated calcium flux, induced gene expression of IL-8, and reduced disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) and collagen 1A1, possibly via upregulated TRPA1. TRPA1 KO in mice was associated with signs of degeneration in the nucleus pulposus and the vertebral growth plate, whereas TRPV1 KO did not show profound changes. Cytokine treatment also affected the gene expression of TRPV2 (increase), TRPV4 (increase), and TRPC6 (decrease). TRPA1 might be expressed in developing IVD, downregulated during its maturation, and upregulated again in degenerative disc disease, participating in matrix homeostasis. However, follow-up studies with larger sample sizes are needed to fully elucidate the role of TRPA1 and other TRP channels in degenerative disc disease.

Tenascin-C promotes the repair of cartilage defects in mice

BackgroundThe effects of tenascin-C (TNC) on cartilage repair were examined in cartilage defect model mice. An in vitro study was also performed to determine the mechanism of cartilage repair with TNC. MethodsFull-thickness osteochondral defects were filled with TNC (group A: 100 μg/ml, group B: 10 μg/ml, group C: empty). Mice were sacrificed at 1, 2, 3, and 6 weeks postoperatively. Cartilage repair was histologically evaluated using the modified WAKITANI score. Chondrocytes were isolated and cultured, and they were treated with TNC. The expressions of various mRNAs including TNC, inflammatory cytokines, and anabolic and catabolic factors for cartilage were compared by real-time polymerase chain reaction. ResultsThe defects in group A were covered with hyaline-like cartilage after 3 weeks. Average modified WAKITANI scores were significantly better in group A than in groups B and C at 3 and 6 weeks. TNC upregulated the expressions of endogenous TNC, inflammatory cytokines, and anabolic and catabolic factors for cartilage. TNC downregulated the expression of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 5. ConclusionsIntra-articular injection of full-length TNC repaired cartilage in murine models of full-thickness osteochondral defects. TNC upregulated the expression of ADAMTS4, but downregulated the expression of ADAMTS5 that contributed to cartilage degradation.

Lixisenatide attenuates advanced glycation end products (AGEs)-induced degradation of extracellular matrix in human primary chondrocytes

Osteoarthritis (OA) poses a growing threat to the health of the global population. Accumulation of advanced glycation end-products (AGEs) has been shown to upregulate expression of degradative enzymes such as matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) in chondrocytes, which leads to excessive degradation of type II collagen and aggrecan in the articular extracellular matrix (ECM). In the present study we investigated the effects of the GLP-1 agonist lixisenatide, a widely used type II diabetes medication, on AGEs-induced decreased mitochondrial membrane potential (MMP), degradation of ECM, oxidative stress, expression of cytokines including interleukin (IL)-1β and IL-6, and activation of nuclear factor kappa B (NF-κB). Our findings indicate that lixisenatide significantly ameliorated the deleterious effects of AGEs in a dose-dependent manner. Thus, lixisenatide has potential as a safe and effective treatment for OA and other AGEs-induced inflammatory diseases.

Peimine suppresses interleukin‑1β‑induced inflammation via MAPK downregulation in chondrocytes.

Osteoarthritis (OA) is the most common type of degenerative joint disease and secreted inflammatory molecules serve a pivotal role in it. Peimine has been reported to have anti‑inflammatory activity. In order to investigate the potential therapeutic role of Peimine in OA, mouse articular chondrocytes were treated with IL‑1β and different doses of Peimine in vitro. The data revealed that Peimine not only suppressed IL‑1β‑induced production of nitric oxide (NO) and prostaglandin E2, but also reduced the protein levels of inducible NO synthase (iNOS) and cyclooxygenase‑2 (COX‑2). In addition, Peimine inhibited the IL‑1β‑induced mRNA expression of matrix metalloproteinase (MMP)‑1, MMP‑3, MMP‑9, MMP‑13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)‑4 and ADAMTS‑5. Furthermore, Peimine inhibited IL‑1β‑induced activation of the mitogen‑activated protein kinase (MAPK) pathway. The protective effect of Peimine on IL‑1β‑treated chondrocytes was attenuated following activation of the MAPK pathway, as demonstrated by the increased expression levels of MMP‑3, MMP‑13, ADAMTS‑5, iNOS and COX‑2 compared with the Peimine group. The in vivo data suggested that Peimine limited the development of OA in the mouse model. In general, the data indicate that Peimine suppresses IL‑1β‑induced inflammation in mouse chondrocytes by inhibiting the MAPK pathway, suggesting a promising therapeutic role for Peimine in the treatment of OA.

Salmon calcitonin exerts better preventive effects than celecoxib on lumbar facet joint degeneration and long-term tactile allodynia in rats.

To evaluate and compare the effects of salmon calcitonin (sCT) and celecoxib (CLX) on cartilage, subchondral bone and tactile allodynia in a rat model of lumbar facet joint (FJ) osteoarthritis (OA). Forty 3-month-old male Sprague-Dawley rats were randomly divided into four groups: 30 received surgical collagenase (type II) injections in the right L3-L6 facet joints followed by 8 weeks of treatment with normal saline, CLX or sCT, and the other 10 received sham surgery. Tactile allodynia, changes of cartilage and subchondral bone of the L4-L5 FJs, and serum biomarkers were analyzed for all rats. Both sCT and CLX ameliorated cartilage lesions, significantly increased aggrecan expression and decreased caspase-3 expression. sCT also decreased the expression of a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS-4). According to the micro-computed tomography (micro-CT) analysis, sCT significantly improved microarchitecture parameters of subchondral bone and micro-CT score; and inhibited articular process hypertrophy. CLX showed better antihyperalgesic effects than sCT on days 3 and 7 postoperatively despite no statistical differences, whereas sCT possessed better analgesic effects than CLX on days 42 and 56. Besides, the sCT treatment reduced the elevated cartilage oligomeric matrix protein (COMP) concentration in rats injected with collagenase (type II). Both sCT and CLX exerted preventive effects on FJ OA caused by collagenase (type II), but sCT showed more protective effects, particularly on maintaining cartilage metabolism, restraining the deterioration of the subchondral bone microarchitecture and tactile allodynia, and reducing serum COMP concentrations.

Effects of AURKA-mediated degradation of SOD2 on mitochondrial dysfunction and cartilage homeostasis in osteoarthritis.

This study aimed to investigate the mechanism of the ubiquitinase Aurora kinase A (AURKA) in the occurrence of osteoarthritis (OA) by mediating mitochondrial stress. Bioinformatic predictions revealed 2247 differentially expressed genes (DEGs) in the normal and OA tissues. According to the UbiNet database, 39 DEGs that code for ubiquitination enzymes was screened. AURKA was highly expressed in OA tissues and cells. AURKA interference inhibited the elevation of matrix metalloproteinase-13 (MMP-13). (MMP13), sex determining region Y-box 9 (Sox9), and a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS5) expression and the reduction of collagen type IIα (Col2a1) and Aggrecan expression in interleukin-1 β (IL-1β) induced chondrocytes. The animal experiments proved that depleting AURKA could repress the occurrence of OA. Superoxide dismutase 2 (SOD2) was determined to be AURKA ubiquitination substrate via AURKA expression and bioinformatic prediction experiments. SOD2 expression was lower in OA tissues, but higher in normal joint tissues. AURKA interference activates SOD2. Meanwhile, the IP results confirmed that AURKA could bind to SOD2 and degrade it through K48 ubiquitination. Modification and overexpression of AURKA reduce SOD2 levels. AURKA interference can reverse the reactive oxygen species elevation caused by SOD2 overexpression or lysine-48 (K48) mutation, respectively, leading to mitochondrial dysfunction. Furthermore, AURKA silencing suppressed the occurrence of OA induced by mitochondrial activation. These findings suggest that ubiquitination of AURKA lowers SOD2 expression and affects mitochondrial dysfunction to repress the occurrence of OA. The results of the current study reveal that AURKA ubiquitination influences mitochondrial dysfunction and suppresses the occurrence of OA via degradation of SOD2. These data reveal novel potential targets for OA treatment.

Associations between second-trimester amniotic fluid levels of ADAMTS4, ADAMTS5, IL-6, and TNF-α and spontaneous preterm delivery in singleton pregnancies.

Background We investigated the roles of inflammatory cytokines and the A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family in the etiopathogenesis of spontaneous preterm delivery by comparing the ADAMTS4, ADAMTS5, interleukin (IL)-6, and tumor necrosis factor-α (TNF-α) levels in second-trimester amniotic fluid between pregnant women with preterm birth and term controls. Methods All pregnant women who underwent second-trimester amniocentesis for genetic analysis between January 1, 2016, and January 1, 2018, were enrolled in this study. From this cohort, 22 patients who subsequently experienced spontaneous preterm delivery before 34 weeks of pregnancy formed the study group, and 22 age- and body mass index (BMI)-matched patients without preterm birth constituted the control group. Results No significant differences were observed between the preterm birth and control groups in terms of age, BMI, obstetric history of preterm delivery, gestational age at amniocentesis, or indication for amniocentesis. The mean amniotic fluid levels of ADAMTS4 and ADAMTS5 were significantly increased in the preterm birth group compared to the control group (248.3±22.6 and 182.4±19.8 pg/mL, P=0.012; and 198.6±21.6 and 159.1±21.7 pg/mL, P=0.035, respectively). Significantly increased IL-6 and TNF-α levels were also detected in the amniotic fluid of women who experienced spontaneous preterm delivery, relative to controls (142.1±16.2 and 95.8±16.4 pg/mL, P<0.001; and 139.4±12.5 and 89.6±11.2 pg/mL, P<0.001, respectively). Conclusion The results of this study imply that increased mid-trimester amniotic fluid levels of ADAMTS4, ADAMTS5, IL-6, and TNF-α play an important role in the pathophysiology of spontaneous preterm delivery.

An ADAMTS Sol narae is required for cell survival in Drosophila

Cell survival is essential for all living organisms to cope against multiple environmental insults. Intercellular signaling between dying and surviving cells plays an important role to ensure compensatory proliferation, preventing tissue loss after environmental stresses. Here, we show that Sol narae (Sona), a Disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) in Drosophila is required for cell survival. sona exhibited a positive genetic interaction with Death-associated inhibitor of apoptosis 1 (Diap1), and a negative genetic interaction with reaper (rpr). Transcription patterns of sona, Diap1, and rpr genes in the pouch region of wing discs were coordinately changed after irradiation. Interestingly, there was a negative correlation in the expression levels of Sona and DIAP1, and both cell types, one with high Sona level and the other with high Diap1 level, were resistant to irradiation-induced cell death. The sona-expressing cells rarely entered into cell cycle themselves but promoted the nearby cells to proliferate in irradiation conditions. We found that these sona-expressing cells are able to upregulate Cyclin D (Cyc D) and increase tissue size. Furthermore, transient Sona overexpression increased survival rate and promoted development of flies in irradiation conditions. We propose that the two types of radiation-resistant cells, one with high Sona level and the other with high Diap1 level, communicate with dying cells and between each other for cell survival and proliferation in response to irradiation.

ADAMTS-9 in Mouse Cartilage Has Aggrecanase Activity That Is Distinct from ADAMTS-4 and ADAMTS-5.

A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5 are the principal aggrecanases in mice and humans; however, mice lacking the catalytic domain of both enzymes (TS-4/5∆cat) have no skeletal phenotype, suggesting there is an alternative aggrecanase for modulating normal growth and development in these mice. We previously identified aggrecanase activity that (a) cleaved at E↓G rather than E↓A bonds in the aggrecan core protein, and (b) was upregulated by retinoic acid but not IL-1α. The present study aimed to identify the alternative aggrecanase. Femoral head cartilage explants from TS-4/5∆cat mice were stimulated with IL-1α or retinoic acid and total RNA was analysed by microarray. In addition to ADAMTS-5 and matrix metalloproteinase (MMP)-13, which are not candidates for the novel aggrecanase, the microarray analyses identified MMP-11, calpain-5 and ADAMTS-9 as candidate aggrecanases upregulated by retinoic acid. When calpain-5 and MMP-11 failed to meet subsequent criteria, ADAMTS-9 emerged as the most likely candidate for the novel aggrecanase. Immunohistochemistry revealed ADAMTS-9 expression throughout the mouse growth plate and strong expression, particularly in the proliferative zone of the TS-4/5-∆cat mice. In conclusion, ADAMTS-9 has a novel specificity for aggrecan, cleaving primarily at E↓G rather than E↓A bonds in mouse cartilage. ADAMTS-9 might have more important roles in normal skeletal development compared with ADAMTS-4 and ADAMTS-5, which have key roles in joint pathology.

Does butein affect adipogenesis?

ABSTRACT Butein is a plant flavonoid chalcone, with presumed anti-adipogenic properties. It was reported to impair preadipocyte differentiation, limit adipose tissue (AT) development and enhance white AT browning in rodents. In this study, we investigated the hypothesis that these effects of butein may occur via reduction of ADAMTS5 (A Disintegrin And Metalloproteinase with ThromboSpondin motifs 5) expression. Murine 3T3-L1 or 3T3-F442A preadipocytes were differentiated into mature adipocytes in the presence of butein or vehicle. At regular time intervals RNA was collected for gene expression studies. Male hemizygous mice for Tg(Ucp1-luc2,-tdTomato)1Kajim (ThermoMouse) were exposed to butein or vehicle, after which ATs were analyzed for Adamts5 and uncoupling protein-1 (Ucp-1) mRNA level changes. During preadipocyte differentiation, butein (25 – 50 mM) did not affect Adamts5 or Ucp-1 expression. Oil Red O analysis and monitoring of differentiation markers failed to demonstrate effects of butein on the differentiation extent. Furthermore, butein administration to the ThermoMouse (10 or 20 mg/kg, 4 days) or to the C57BL6/Rj mice (20 mg/kg, 4 weeks) did not enhance Adamts5 or Ucp-1 expression. Thus, we could not demonstrate marked effects of butein on the preadipocyte differentiation extent or AT development and browning, nor on Adamts5 or Ucp-1 gene expression during these processes.

LncRNA MALAT1/MiR-145 Adjusts IL-1β-Induced Chondrocytes Viability and Cartilage Matrix Degradation by Regulating ADAMTS5 in Human Osteoarthritis.

PurposeAccumulating evidence suggests that microRNA-145 (miR-145) plays an important role in osteoarthritis (OA), which is a chronic progressive joint disease. Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) promotes metastasis in cancers and functions as a sponge for miR-145. However, the role of MALAT1/miR-145 in OA pathogenesis has not yet been elucidated.Materials and MethodsThe expression of MALAT1 and miR-145 was examined by quantitative real-time PCR; the interaction between miR-145, MALAT1 and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) 5 was verified by luciferase reporter assay. Correlations among MALAT1, miR-145, and ADAMTS5 were analyzed by Spearman rank analysis. Chondrocytes viability and cartilage extracellular matrix (ECM) degradation were investigated with cell viability assay and Western blotting analyzing expression of ADAMTS5, collagen type 2 alpha 1 (COL2A1), aggrecan (ACAN), and cartilage oligomeric matrix protein (COMP).ResultsMALAT1 was upregulated, and miR-145 was downregulated in OA samples and IL-1β-induced chondrocytes. Mechanically, miR-145 could directly bind to MALAT1 and ADAMTS5. Moreover, miR-145 expression was negatively correlated with MALAT1 and ADAMTS5 expression in OA patients, whereas MALAT1 and ADAMTS5 expression was positively correlated. Functionally, overexpression of MALAT1 inhibited chondrocyte viability and promoted cartilage ECM degradation in IL-1β-induced chondrocytes. In support thereof, MALAT1 silencing and miR-145 upregulation exerted the opposite effect in IL-1β-induced chondrocytes. Moreover, the effect of MALAT1 was counteracted by miR-145 upregulation, and ADAMTS5 restoration could abate miR-145 effects.ConclusionAn MALAT1/miR-145 axis contributes to ECM degradation in IL-1β-induced chondrocytes through targeting ADAMTS5, suggesting that MALAT1/miR-145/ADAMTS5 signaling may underlie human OA pathogenesis.

HnRNPK a Possible Mechanosensitive Gene: Its Function in Chondrocytes and Osteoarthritis

Mechanical stimulation contributes to the development, homeostasis, integrity and functionality of the articular cartilage by modulating several cellular activities including production and remodeling of extracellular matrix (ECM), chondrocyte differentiation, proliferation and apoptosis. On the other hand, abnormal mechanical strain play a critical role in osteoarthritis (OA) pathogenesis by inducing ECM degradation and chondrocyte apoptosis. Furthermore, deleterious mechanical loading can also stimulates the production of pro-inflammatory mediators such as interleukin 1β (IL-1β) that promote to cartilage degradation, chondrocyte hypertrophy and inflammation [1]. Heterogeneous nuclear ribonucleoprotein K (hnRNPK), a member of the hnRNP family, is implicated in the expression, stabilization and organization of the cytoskeleton in neurons and fibroblast, suggesting that it might be involved in the regulation of cellular mechanical properties and mechanotransduction[2, 3]. However, it is still unclear whether hnRNPK participates in chondrocyte response to mechanical stimuli and osteoarthritis progression. The current study aimed to investigate the role of hnRNPK in chondrocyte mechanotransduction and establish its link in osteoarthritis development and progression. Here, we used cyclic tensile stress (CTS) method to examine the hypothesis that mechanical stimulation of chondrocytes alters the expression of hnRNPK. Furthermore, we studied the effect of hnRNPK siRNA on chondrocyte response to IL-1β and mechanical stimulation in chondrocytes. To validate its involvement in osteoarthritis, hnRNPK expression in chondrocytes isolated from normal and osteoarthritis cartilage was also investigated. hnRNPK is differentially expressed in normal and osteoarthritis chondrocytes and its expression is altered following CTS loading and IL-1β exposure. Chondrocyte cytoskeleton proteins (F-actin and vimentin), chondrogenic markers (type II collagen and aggrecan) and proteinase (matrix metalloproteinase 13(MMP-13) and A disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS4)) were identified as hnRNPK- regulated genes. Furthermore, downregulation of hnRNPK increased chondrocyte sensitivity to IL-1β, which was demonstrated by increased chondrocyte apoptosis and the expression of catabolic and hypertrophic markers. In conclusion, hnRNPK plays an essential role in maintaining chondrocyte phenotype and survival, and the regulation of ECM production and remodeling. Finally, mechanical loading and inflammation might promote osteoarthritis progression through the downregulation of hnRNPK.

ADAMTS18 Deficiency Affects Neuronal Morphogenesis and Reduces the Levels of Depression-like Behaviors in Mice

The ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) enzymes are secreted, multi-domain matrix-associated zinc metalloendopeptidases that modify extracellular matrix components and play crucial roles in development and numerous diseases. ADAMTS18 is a member of the ADAMTS family, and genome-wide association studies made an initial association of ADAMTS18 with white matter integrity in healthy people of 72–74 years old. However, the potential roles of ADAMTS18 in central nervous system remain unclear. In this study, we showed that Adamts18 mRNA is highly abundant in developing brains, especially in the cerebellum granular cell layer and the hippocampus dentate gyrus (DG) granular cell layer. Adamts18 knockout (KO) mice displayed higher dendritic branching complexity and spine density on hippocampal DG granular cells. Behavioral tests showed that Adamts18 KO mice had reduced levels of depression-like behaviors compared to their wild-type (WT) littermates. The increased neurite formation could be attributed in part to reduced phosphorylation levels of the collapsin response mediator protein-2 (CRMP2) due to activation of the laminin/PI3K/AKT/GSK-3β signaling pathway. Our findings revealed a critical role of ADAMTS18 in neuronal morphogenesis and emotional control in mice.

Fibrin-hyaluronic acid hydrogel-based delivery of antisense oligonucleotides for ADAMTS5 inhibition in co-delivered and resident joint cells in osteoarthritis

To date no disease-modifying drugs for osteoarthritis (OA) are available, with treatment limited to the use of pain killers and prosthetic replacement. The ADAMTS (A Disintegrin and Metallo Proteinase with Thrombospondin Motifs) enzyme family is thought to be instrumental in the loss of proteoglycans during cartilage degeneration in OA, and their inhibition was shown to reverse osteoarthritic cartilage degeneration. Locked Nucleic Acid (LNA)-modified antisense oligonucleotides (gapmers) released from biomaterial scaffolds for specific and prolonged ADAMTS inhibition in co-delivered and resident chondrocytes, is an attractive therapeutic strategy. Here, a gapmer sequence identified from a gapmer screen showed 90% ADAMTS5 silencing in a monolayer culture of human OA chondrocytes. Incorporation of the gapmer in a fibrin-hyaluronic acid hydrogel exhibited a sustained release profile up to 14 days. Gapmers loaded in hydrogels were able to transfect both co-embedded chondrocytes and chondrocytes in a neighboring gapmer-free hydrogel, as demonstrated by flow cytometry and confocal microscopy. Efficient knockdown of ADAMTS5 was shown up to 14 days in both cell populations, i.e. the gapmer-loaded and gapmer-free hydrogel. This work demonstrates the use applicability of a hydrogel as a platform for combined local delivery of chondrocytes and an ADAMTS-targeting gapmer for catabolic gene modulation in OA.

The inhibitory effects of rosmarinic acid on catabolism induced by IL-1β in rat chondrocyte.

The effects of rosmarinic acid (RosA) on osteoarthritis (OA) was investigated in rat chondrocytes. Chondrocytes were isolated from rat cartilage, incubated with RosA in the presence of interleukin-1beta (IL-1β) (10 ng/ml). The production of IL-6, as well as the mRNA level of aggrecan (ACAN) and collagen 2 (COL2), were assessed. The gene and protein expression of A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, ADAMTS-5 were also measured. RosA inhibited the production of IL-6 as well as the gene and protein expression of ADAMTS-4 and ADAMTS-5, in addition, RosA abolished IL-1β-induced inhibition of ACAN and COL2 gene expression. Our results suggest that RosA can inhibit extracellular matrix (ECM) degradation in OA, thus, RosA may be a possible agent in the treatment of OA.

Ivabradine abrogates TNF-α-induced degradation of articular cartilage matrix

Ivabradine is most commonly used for the treatment of worsening cardiac failure in patients who cannot tolerate the maximum dose of β-blockers or in whom treatment with β-blockers is contraindicated. While ivabradine is regarded as a highly selective “funny current” (If) inhibitor, the molecular mechanism behind the effect of this drug remains poorly understood. In the present study, we applied ivabradine in the context of osteoarthritis by treating primary human chondrocytes with tumor necrosis factor-α (TNF-α) and measuring degradation of the articular cartilage matrix as well as the expression of various enzymes and pro-inflammatory cytokines. Our results indicate that ivabradine significantly abrogated TNF-α-induced up-regulation of matrix metalloproteinase-3 (MMP-3), MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, and ADAMTS-5 at both the gene and protein levels. Notably, ivabradine attenuated TNF-α-induced reduction of type II collagen and aggrecan at both the mRNA and protein levels. Also, we found that ivabradine inhibited the expression and secretion of interleukin-6 (IL-6) and interleukin-1β (IL-1β) as well as the production of reactive oxygen species (ROS). Mechanistically, our results indicate that ivabradine abolished the activation of nuclear factor (NF-κB) by inhibiting nuclear translocation of NF-κB p65. Knockdown of HCN2 enhanced the protective effects of ivabradine against TNF-α- induced degradation of both type II collagen and aggrecan, suggesting that the inhibitory effects of ivabradine in ECM degradation might be mediated by HCN2. Our findings demonstrate that ivabradine may indeed have a potential application in preventing excessive degradation of the articular cartilage matrix, thereby preventing the pathological development and progression of osteoarthritis.

Vascular Proteomics Reveals Critical Roles of ADAMTS18 in Stroke Associated with Imbalanced Level of Von Willebrand Factor Versus ADAMTS13

Background and Purpose-Stroke is the second leading cause of death worldwide. Acute ischemic stroke (AIS) is frequently induced by internal carotid artery thrombosis. Clinically, most arterial thrombus formation is initiated by platelets adhering to the damaged vessel wall. The adherent platelets become activated and bind with fibrinogen and von Willebrand factor (vWF), allowing formation of a platelet aggregate or mural thrombus. Identifying new mechanism involved in this pathogenesis is critical for understanding the molecular basis of thrombus formation and ultimately developing new therapeutic interventions for stroke. The ADAMTS (A disintegrin and metalloproteinase with thrombospondin motifs) family comprises 19 secreted metalloproteinases that cleave extracellular matrix components and have diverse functions in numerous disease and physiological contexts. Several ADAMTS genes (ADAMTS -7,-8, 12, and 13) have been shown to be involved in cardiovascular disease and pediatric stroke. ADAMTS18 remains “orphan” protease. We have previously shown that ADAMTS18 deficiency causes abnormal remodeling of the common carotid artery (CCA) and an increase in carotid thrombosis and size of cerebral infarct in mice. Thus, the stroke-prone Adamts18 KO mice could be valuable for identification of molecular signatures of accelerated carotid thrombosis related to stroke. One of the major steps yet to be taken by the field is the widespread use of proteomics to uncover the critical molecular events and signaling pathway involved in ADAMTS gene-related stroke.Methods and Results-Here, we carried out the first proteomics comparison of protein expression patterns in CCA and abdominal artery (AA) between Adamts18 knockout (KO) mice and their wild-type (WT) littermates. A total of 1654 proteins were identified in four separate CCA samples (0.4-1 mg/wet weight each), and 1810 proteins were detected in four separate AA samples (2.3-3.6 mg/wet weight each). The abundances of 154 proteins in CCA and 55 proteins in AA were significantly different between KO and WT mice. Ingenuity® Pathway Analysis revealed that ADAMTS18 deficiency predisposes mice to stroke by altering the abundance of many proteins related to cytoskeleton, prothrombotic activity, coagulation, angiogenesis, oxidative homeostasis, and energy metabolism. Western blotting and qRT-PCR analyses further revealed the imbalanced level of von Willebrand factor and ADAMTS13, the pivotal pathogenic factors of ischemic stroke, in CCA of KO mice.Conclusion and Significance-Results of this first vascular proteomic study of Adamts18 KO mice establish a substantial new resource for investigation of how ADAMTS gene affects cellular phenotypes of stroke. These new findings contribute to inform novel prevention strategies and direct therapeutic development for stroke. DisclosuresNo relevant conflicts of interest to declare.

Vildagliptin reduced extracellular matrix degradation in human primary chondrocytes

In the present study, we investigated the effects of the specific DPP-4 inhibitor vildagliptin on degradation of type II collagen and aggrecan, the main components of the articular extracellular matrix, in primary human chondrocytes. The results of our study reveal that vildagliptin reduced degradation of the articular extracellular matrix (ECM) by downregulating IL-1β-induced expression of matrix metalloproteinases-3 (MMP-3), matrix metalloproteinases-13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4) and a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5). We also found that vildagliptin ameliorated IL-1β-induced activation of the JNK/AP-1 and nuclear factor-κB (NF-κB) pro-inflammatory signaling pathways by downregulating phosphorylation of JNK and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor α (IκBα), activation of c-Fos/c-Jun, and nuclear translocation of p65. Our findings suggest that vildagliptin may serve as a novel treatment for excessive degradation of the articular ECM in osteoarthritis (OA).

The metalloprotease ADAMTS4 generates N-truncated Aβ4-x species and marks oligodendrocytes as a source of amyloidogenic peptides in Alzheimer's disease.

Brain accumulation and aggregation of amyloid-β (Aβ) peptides is a critical step in the pathogenesis of Alzheimer's disease (AD). Full-length Aβ peptides (mainly Aβ1-40 and Aβ1-42) are produced through sequential proteolytic cleavage of the amyloid precursor protein (APP) by β- and γ-secretases. However, studies of autopsy brain samples from AD patients have demonstrated that a large fraction of insoluble Aβ peptides are truncated at the N-terminus, with Aβ4-x peptides being particularly abundant. Aβ4-x peptides are highly aggregation prone, but their origin and any proteases involved in their generation are unknown. We have identified a recognition site for the secreted metalloprotease ADAMTS4 (a disintegrin and metalloproteinase with thrombospondin motifs 4) in the Aβ peptide sequence, which facilitates Aβ4-x peptide generation. Inducible overexpression of ADAMTS4 in HEK293 cells resulted in the secretion of Aβ4-40 but unchanged levels of Aβ1-x peptides. In the 5xFAD mouse model of amyloidosis, Aβ4-x peptides were present not only in amyloid plaque cores and vessel walls, but also in white matter structures co-localized with axonal APP. In the ADAMTS4-/- knockout background, Aβ4-40 levels were reduced confirming a pivotal role of ADAMTS4 in vivo. Surprisingly, in the adult murine brain, ADAMTS4 was exclusively expressed in oligodendrocytes. Cultured oligodendrocytes secreted a variety of Aβ species, but Aβ4-40 peptides were absent in cultures derived from ADAMTS4-/- mice indicating that the enzyme was essential for Aβ4-x production in this cell type. These findings establish an enzymatic mechanism for the generation of Aβ4-x peptides. They further identify oligodendrocytes as a source of these highly amyloidogenic Aβ peptides.

Efficiency of dual siRNA-mediated gene therapy for intervertebral disc degeneration (IVDD)

BACKGROUND CONTEXTOne of the common causes of low back pain is intervertebral disc degeneration. The pathophysiology of disc degeneration involves apoptosis of nucleus pulposes cells and degradation of extra cellular matrix (ECM). Caspase 3 plays a central role in apoptosis and the ADAMTS5 (A Disintegrin and Metalloproteinase with Thrombospondin motifs 5) gene plays a critical role in ECM degradation. Hence, we hypothesized that if one can silence these two genes, both apoptosis and ECM degradation can be prevented, thereby preventing the progression and even reverse disc degeneration. PURPOSEThe purpose of this study is to demonstrate the regenerative potential of small interfering RNA (siRNA) designed against Caspase 3 and ADAMTS5 genes in an in vitro and animal model of disc degeneration. STUDY DESIGNIn vitro study followed by in vivo study in a rabbit model. METHODSIn vitro studies were done using the human hepatocellular carcinoma (Hep G2) cell line for validating the efficacy of liposomal siRNA in controlling the expression of genes (Caspase 3 and ADAMTS5). Later, siRNA's validation was done in a rabbit annular punctured model by administering siRNA's individually (Caspase 3 and ADAMTS5) and in combination Caspase3-ADAMTS5) for assessing their synergistic effect in down regulating the gene expression in the degenerative discs. Annular punctured intervertebral discs of the rabbit were injected with siRNA formulations (single and dual) and phosphate buffer saline, one week after initial puncture. Magnetic resonance imaging (MRI) scans were done before and after siRNA treatment (1, 4 and 8 weeks) for assessing the progression of disc degeneration. The histopathology and real time polymerase chain reaction (RT-PCR) studies were done for evaluating their efficacy. We did not receive any funding for conducting the study, and we do not have a conflict of interest with any researchers or scientific groups. RESULTSThe observations made from both in vitro and in vivo studies indicate the beneficial effects of siRNA formulation in down regulating the expression of Caspase 3 and ADAMTS5 genes. The MRI and histopathological evaluation showed that the disc degeneration was progressive in phosphate buffer saline and AT5-siRNA injected discs but the discs that received Caspase 3-siRNA and dual siRNA (Cas3-AT5-siRNA) formulation showed signs of recovery and regeneration 4 and 8 weeks after injection. The efficacy of siRNA designed against Cas3 and AT5 was also assessed in both in vitro and in vivo experiments by using RT-PCR analysis and the results showed downregulation of Caspase 3 gene in Caspase 3-siRNA group, but there was no significant downregulation of ADAMTS5 gene in ADAMTS5-siRNA group (ie, indicated by fold change). Synergistic effect was observed in the group that received dual siRNA (Cas3-AT5 siRNA) formulation. CONCLUSIONSThis experiment suggests that intervention by siRNA treatment significantly reduced the extent of apoptosis in the discs. CLINICAL SIGNIFICANCEDelivery of siRNA directly into spinal discs has a potential in treating disc degeneration nonsurgically.