Project description:Objective: To Identify gene changes in the medial tibial plateau of articular cartilage at 2, 4 and 8 weeks after destabilisation of the medial meniscus (DMM) in mice and compare our data set with previously published sets to ascertain dysregulated pathways and genes in osteoarthritis. Materials and methods: RNA was extracted from the ipsilateral and contralateral medial tibial plateaus, amplified, labelled and hybridized on Illumina WG_v2 microarrays. Results were confirmed by RT-PCR for selected genes. Results: Transcriptional analysis and network reconstruction revealed changes in extracellular matrix (ECM) and cytoskeletal genes induced by DMM. TGFalpha signalling pathway and complement and coagulation cascade genes were regulated at 2 weeks. Fibronectin (FN1) is a hub in a reconstructed network of potential protein-protein interactions at 2 weeks. Regulated genes decrease over time and by eight weeks fibromodulin (FMOD) and tenascin N (TNN) are the only dysregulated genes present in the DMM operated knees. Comparison with human and rodent published gene sets discovered genes overlapping between our array and 6 others. Conclusions: Cartilage contributes a minute percentage to the RNA extracted from the whole joint (>0.2%), yet is sensitive to changes in gene expression post-DMM. The post-DMM transcriptional reprogramming wanes over time and dissipates by 8 weeks. Common pathways between published gene sets include focal adhesion, regulation of actin cytoskeleton and TGFalpha. Common genes include Jagged 1 (Jag1), Tetraspanin 2 (Tspan2), neuroblastoma, suppression of tumourigenicity 1 (Nbl1) and N-myc downstream regulated gene 2 (Ndrg2). The concomitant genes and pathways we identify are novel and warrant further investigation as biomarkers or modulators of osteoarthritis. In total 18 samples. Each sample was a pool of the medial tibial plateau of 8 mice. Two categories (Treated and untreated) with three biological replicates each and three time points (2, 4 and 8 weeks post-surgery).

Project description:Background: Meniscus tears are the most common injury in the knee and are associated with an increased risk of osteoarthritis (OA). The molecular profile of knees with meniscus tears is not well-studied. Therefore, to advance our understanding of the early response of the knee to injury, we compared the gene expression profile of meniscus and articular cartilage within the same knees following meniscus injury. Hypothesis/Purpose: To identify differences between the molecular signatures of meniscus and articular cartilage from knees with intact articular cartilage undergoing arthroscopic partial meniscectomy. Study Design: Descriptive laboratory study Methods: Patients (n=12) with a known isolated medial meniscus tear without any knee chondrosis or radiographic OA were consented prior to surgery. During arthroscopic partial meniscectomy, a sample of their injured meniscus and a sample of their articular cartilage off the medial femoral condyle were procured. The transcriptome signatures, as measured through Affymetrix microarray, were compared between the two tissues and underlying biological processes were explored computationally. Results: 3566 gene transcripts were differentially expressed between meniscus and articular cartilage. Gene transcripts down-regulated in articular cartilage were associated with extracellular matrix organization, wound healing, cell adhesion, and chemotaxis. Gene transcripts up-regulated in articular cartilage were associated with blood vessels morphogenesis and angiogenesis. Examples of individual genes with significant differences in expression between the two tissues include IBSP (23.76 fold; P < 0.001), upregulated in meniscus, and TREM1 (3.23 fold; P = 0.006), upregulated in meniscus. Conclusion: The meniscus and articular cartilage have distinct gene expression profiles in knees with meniscus tears and intact articular cartilage. Total RNA obtained from injured meniscus and normal articular cartilage from patients undergoing partial meniscectomy.

Project description:The purpose of this study was to characterize the histologic development of OA in a mouse model where OA is induced by destabilization of the medial meniscus (DMM model) and to identify genes regulated during different stages of the disease, using RNA isolated from the joint M-bM-^@M-^\organM-bM-^@M-^] and analyzed using microarrays.427 genes from the microarrays passed consistency and significance filters. There was an initial up-regulation at 2 and 4 weeks of genes involved in morphogenesis, differentiation, and development, including growth factor and matrix genes, as well as transcription factors including Atf2, Creb3l1, and Erg. Most genes were off or down-regulated at 8 weeks with the most highly down-regulated genes involved in cell division and the cytoskeleton. Gene expression increased at 16 weeks, in particular extracellular matrix genes including Prelp, Col3a1 and fibromodulin.The results support a phasic development of OA with early matrix remodelling and transcriptional activity followed by a more quiescent period that is not maintained. A group of 9 mice was used for collection of RNA at time 0 (before surgery) when the animals were 12 weeks old. For the other time points, 9 DMM and 9 sham controls were sacrificed at 2, 4, 8, and 16 weeks after surgery for RNA isolation. The tissue included tibial plateau and femoral condyle articular cartilage, subchondral bone with any osteophytes, meniscus, and the joint capsule with synovium was used for RNA isolation. The tissue was treated with RNAlaterM-BM-. (Invitrogen) prior to freezing and storage at -800 C. RNA was extracted by homogenization using the Precellys 24 tissue homogenizer (Bertin Technologies purchased from MO BIO) and the amount and quality of the RNA was determined using an Agilent 2100 Bioanalyzer. RNA was pooled prior to microarray analysis such that 3 randomly selected samples from each surgical group and time point were pooled to create each biological replicate. Because 9 mice were used for each experimental group, a total of three biological replicates per group were analyzed using the Affymetrix Mouse Genome 430 2.0 oligonucleotide arrays as described. One replicate pool, which was from week two DMM mice, did not meet the RNA integrity level needed for microarray analysis; thus, this pool was not analyzed further, leaving two pools for the week two DMM mice.

Project description:Objective Animal models of post-traumatic osteoarthritis (PTOA) recapitulate the pathological changes observed in human PTOA. Here we aimed to compare the cartilage transcriptome responses of a non-surgical, mechanically induced rupture of the anterior cruciate ligament (ACL) model and the surgical destabilisation of the medial meniscus (DMM) model. Methods Skeletally mature male C57Bl6 mice were subjected to either the non-surgical, mechanical ACL rupture or surgical DMM models and transcriptome profiling performed on micro-dissected cartilage at day 7 and 42 post-procedure, respectively; in general, naïve animals served as controls. MicroRNA profiling was also performed on the ACL rupture model. Expression levels of a miRNA of interest, miR-199-5p, were inhibited in primary human articular chondrocytes (HAC) with RNA-seq and 3’UTR assays used to identify and valid potential target genes. Results The number of differentially expressed genes between the two models were comparable and highly correlative (Spearman R =0.8, P<2.2E-16). Gene ontology enrichment analysis identified similarly enriched pathways, containing anabolic terms including ‘extracellular matrix organisation’ enriched for the upregulated genes. Within the ACL rupture miRNA transcriptome, miR-199-5p family members were amongst the most abundantly, and differentially expressed, which was replicated in the DMM cartilage by qRT-PCR. Inhibition of miR-199-5p in HAC led to a comparable transcriptome response to that observed in both human OA damaged vs intact cartilage and murine DMM cartilage datasets. Several genes, including GIT1, NCEH1, SOS2 and ECE1 were all experimentally verified as targets. Conclusion For the first time, we have characterised both the mRNA and miRNA articular cartilage signature in the ACL rupture model and demonstrated highly correlative responses with the DMM PTOA model. These data support the use of the ACL rupture model as a non-invasive alternative to DMM.

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RNA-seq of superficial-zone articular cartilage in a DMM-induced osteoarthritis mouse model

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