Project description:The aim of this study was to characterize the genome-wide DNA methylation profiles of adult baboon femur trabecular bone samples (n=28) and identify how they relate to aspects of femur bone morphology. The Illumina Infinium MethylationEPIC Array was used to assess these genome-wide methylation patterns.
Project description:Osteoarthritis (OA) is a chronic disease of the joint characterized by a progressive degradation of articular cartilage and subchondral bone. In healthy tissue, specialized cells called chondrocytes are regulating a balanced cartilage catabolism and anabolism. By contrast osteoarthritic joints are characterized by a dramatic increase of cartilage catabolism, due to changes of gene expression patterns within chondrocytes. To identify potential epigenetic differences regulating this process a genome-wide methylation screening of paired unaffected and osteoarthritic knee cartilage samples was performed. Therefore samples of macroscopic arthritic and non-arthritic cartilage areas of the femoral condyle of five female patients were collected and DNA isolation was performed. For being able to investigate methylation changes on a genome-wide scale using only limited amounts of DNA a specific amplification protocol for mainly methylated DNA has been established, based on combinations of different methylation-sensitive and M-bM-^@M-^Sindependent restriction digestions. The amplified DNA was then labeled and hybridized onto Agilent M-bM-^@M-^\Human Promoter Whole GenomeM-bM-^@M-^] microarrays. A random variance t-test for paired (per patient) samples was performed, identifying 1214 differentially methylated genetic targets between arthritic and non-arthritic samples. The biological relevance of these genes was then further investigated via Gene Ontology (GO) and KEGG pathway analysis. DNA isolated of paired arthritic and non-arthritic knee cartilage samples of five different female osteoarthritis patients (10 samples) was methylation-specifically amplified using combinations of methylation-sensitive and -insensitive restriction enzymes. Amplicons were dye labeled (Cy3) and hybridized onto 2x244k Agilent Human Promoter microarrays.
Project description:To date, all of the prior osteoarthritic microarray studies in human tissue have focused on the overlying articular cartilage, meniscus, or synovium but not the underlying subchondral bone. In our previous study, our group developed a methodology for high quality RNA isolation from site-matched cartilage and bone from human knee joints, which allowed us to perform candidate gene expression analysis on the subchohndral bone (published on Osteoarthritis and Cartilage on Dec/5/2012 (doi: 10.1016/j.joca.2012.11.016). To the best of our knowledge, the current study is the first to successfully perform whole-genome microarray profiling analyses of human osteoarthritic subchondral bone. We believe our comprehensive microarray results can improve the understanding of the pathogenesis of osteoarthritis and could further contribute to the development of new biomarker and therapeutic strategies in osteoarthritis. Following histological assessment of the integrity of overlying cartilage and the severity of bone abnormality by microcomputed tomography, we isolated total RNA from regions of interest from human OA (n=20) and non-OA (n=5) knee lateral and medial tibial plateaus (LT and MT). A whole-genome profiling study was performed on an Agilent microarray platform and analyzed using Agilent GeneSpring GX11.5. Confirmatory quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis was performed on samples from nine OA individuals to confirm differential expression of 85 genes identified by microarray. Ingenuity Pathway Analysis (IPA) was used to investigate canonical pathways and immunohistochemical staining was performed to validate protein expression levels in samples.
Project description:Osteoarthritis (OA) is a chronic disease of the joint characterized by a progressive degradation of articular cartilage and subchondral bone. In healthy tissue, specialized cells called chondrocytes are regulating a balanced cartilage catabolism and anabolism. By contrast osteoarthritic joints are characterized by a dramatic increase of cartilage catabolism, due to changes of gene expression patterns within chondrocytes. To identify potential epigenetic differences regulating this process a genome-wide methylation screening of paired unaffected and osteoarthritic knee cartilage samples was performed. Therefore samples of macroscopic arthritic and non-arthritic cartilage areas of the femoral condyle of five female patients were collected and DNA isolation was performed. For being able to investigate methylation changes on a genome-wide scale using only limited amounts of DNA a specific amplification protocol for mainly methylated DNA has been established, based on combinations of different methylation-sensitive and –independent restriction digestions. The amplified DNA was then labeled and hybridized onto Agilent “Human Promoter Whole Genome” microarrays. A random variance t-test for paired (per patient) samples was performed, identifying 1214 differentially methylated genetic targets between arthritic and non-arthritic samples. The biological relevance of these genes was then further investigated via Gene Ontology (GO) and KEGG pathway analysis.
Project description:The aim of this study was to identify DNA methylation patterns in femur trabecular bone and cartilage of adult baboons (n=28 with knee OA, n=28 without knee OA). The Illumina Infinium MethylationEPIC Array was used to assess these genome-wide methylation patterns.
Project description:This data set consists of tissue-specific RNA-seq reads from 14 different tissues from a single female adult olive baboon (Papio anubis): bone marrow, brain cerebellum, brain frontal cortex, brain pituitary, brain temporal lobe, colon, heart, kidney, liver, lymph node, spleen, lung, skeletal muscle and thymus. The data set was generated by the non-human primate reference transcriptome resource (NHPRTR) project (http://nhprtr.org/), and was first made public on 14 Jan 2014.
Project description:Osteoarthritis (OA) is the most common joint disease and this is a major cause of joint pain and disability in the aging population. Its etiology is multifactorial (i.e., age, obesity, joint injury, genetic predisposition), and the pathophysiologic process affects the entirety of the joint (Martel-Pelletier J et al. Osteoarthritis. Nature reviews Disease primers. 2016;2:16072). Although it is not yet clear if it precedes or occurs subsequently to cartilage damage, subchondral bone sclerosis is an important feature in OA pathophysiology (Goldring SR et al. Changes in the osteochondral unit during osteoarthritis: structure, function and cartilage-bone crosstalk. Nat Rev Rheumatol. 2016;12:632-44). It is characterized by local bone resorption and the accumulation of weakly mineralized osteoid substance (Bailey AJ et al. Phenotypic expression of osteoblast collagen in osteoarthritic bone: production of type I homotrimer. Int J Biochem Cell Biol. 2002;34:176-82). Subchondral bone sclerosis is suspected to be linked to cartilage degradation, not only by modifying the mechanical stresses transmitted to the cartilage, but also by releasing biochemical factors with an activity on cartilage metabolism (Sanchez C et al. Osteoblasts from the sclerotic subchondral bone downregulate aggrecan but upregulate metalloproteinases expression by chondrocytes. This effect is mimicked by interleukin-6, -1beta and oncostatin M pre-treated non-sclerotic osteoblasts. Osteoarthritis Cartilage. 2005;13:979-87; Sanchez C et al. Subchondral bone osteoblasts induce phenotypic changes in human osteoarthritic chondrocytes. Osteoarthritis Cartilage. 2005;13:988-97; Westacott CI et al J. Alteration of cartilage metabolism by cells from osteoarthritic bone. Arthritis Rheum. 1997;40:1282-91. We have previously demonstrated that osteoblasts isolated from subchondral OA bone exhibited an altered phenotype. More precisely, we showed that osteoblasts coming from the thickening (called sclerotic, SC) of subchondral bone located just below a cartilage lesion produced higher levels of alkaline phosphatase, interleukin (IL)-6, IL-8, prostaglandinE2, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-9 and transforming growth factor(TGF)-β1 and type I collagen than osteoblasts coming from the non-thickening neighboring area (called non-sclerotic area, NSC) (Sanchez C et al. Phenotypic characterization of osteoblasts from the sclerotic zones of osteoarthritic subchondral bone. Arthritis Rheum. 2008;58:442-55; Sanchez C et al. Regulation of subchondral bone osteoblast metabolism by cyclic compression. Arthritis Rheum. 2012;64:1193-203.) To compare secretome of cells living in different in vivo conditions is useful, not only to better understand the pathological mechanisms underlying changes in OA subchondral bone, but also to identify soluble biomarkers potentially reflecting these changes. Using our well-characterised human subchondral osteoblast culture model, we compared the secretome of osteoblasts coming from sclerotic and non sclerotic OA subchondral bone. This approach allowed to identify changes in secretome that contribute to explain some subchondral bone abnormalities in OA and to propose osteomodulin and fibulin-3 as potential biomarkers of OA subchondral bone remodelling.