Project description:Osteoarthritis (OA) is a degenerative joint disease characterized by progressive cartilage loss, bone remodeling, synovial inflammation, and significant joint pain, often resulting in disability. Injury to the synovial joint such as the anterior cruciate ligament (ACL) tear is the major cause of OA in young adults. Currently, there are no approved therapies available to prevent joint degeneration or rebuild articular cartilage destroyed by OA, primarily because our understanding of the cellular and molecular changes that contribute to joint damage is very limited. The synovial joint is a complex structure composed of several tissues including articular cartilage, subchondral bone, synovium, synovial fluid, and tensile tissues including tendons and ligaments. In the present study, using single-cell RNA sequencing (scRNA-seq), we examined the cellular heterogeneity in articular cartilage from mouse knee joints and determined the knee joint injury-induced early molecular changes in the chondrocytes that could contribute to OA.
Project description:Induced pluripotent stem cells (iPSCs) are a promising resource for allogeneic cartilage transplantation to treat articular cartilage defects that do not heal spontaneously and often progress to debilitating conditions, such as osteoarthritis. However, to the best of our knowledge, allogeneic cartilage transplantation into primate models has never been assessed. Here, we show that allogeneic iPSC-derived cartilage organoids survive and integrate as well as function as articular cartilage in a primate model of chondral defects in the knee joints. Histological analysis revealed that allogeneic iPSC-derived cartilage organoids in chondral defects elicited no immune reaction and directly contributed to the tissue repair for at least four months. iPSC-derived cartilage organoids integrated with the host native articular cartilage and prevented degeneration of the surrounding cartilage. Single-cell RNA-sequence analysis indicated that iPSC-derived cartilage organoids differentiated after transplantation, acquiring expression of PRG4 that is crucial for joint lubrication. Pathway analysis suggested the involvement of SIK3 inactivation, verified through molecular experiments. Our study outcomes suggest that allogeneic transplantation of iPSC-derived cartilage organoids may be clinically applicable for the treatment of patients with chondral defects of the articular cartilage.
Project description:The aim of the current study was to identify molecular markers for articular cartilage that can be used for the quality control of tissue engineered cartilage. Therefore a genom-wide expression analysis was performed using RNA isolated from articular and growth plate cartilage, both extracted from the knee joints of minipigs. Keywords: Native material or primary cells isolated from articular cartilage and growth plate cartilage Articular and growth plate cartilage were taken for RNA extraction and hybridization on Affymetrix microarrays. Furthermore chondrocytes from each type of cartilage were isolated and cell culture was started and terminated at day 10 or day 20. Total RNA from cultivated cells was extracted, and hybridization on Affymetrix microarrays was performed.
Project description:The aim of the current study was to identify molecular markers for articular cartilage that can be used for the quality control of tissue engineered cartilage. Therefore a genom-wide expression analysis was performed using RNA isolated from articular and growth plate cartilage, both extracted from the knee joints of minipigs. Keywords: Native material or primary cells isolated from articular cartilage and growth plate cartilage
Project description:Chondrocyte gene expression was analyzed to study mechanisms involved in the structural and functional adaptation of articular cartilage during postnatal maturation. Transcriptional profiling was used to compare articular chondrocytes between four neonatal and four adult horses. Expressional differences featured matrix proteins and matrix-modifying enzymes reflecting the transition from cartilage growth to cartilage homeostasis. Keywords: articular cartilage, maturation, horse, cDNA microarray
Project description:Articular cartilage is deprived of blood vessels and nerves, and the only cells residing in this tissue are chondrocytes. The molecular properties of the articular cartilage and the architecture of the extracellular matrix demonstrate a complex structure that differentiates on the depth of tissue. Osteoarthritis (OA) is a degenerative joint disease, the most common form of arthritis, affecting the whole joint. It is associated with ageing and affects the joints that have been continually stressed throughout life including the knees, hips, fingers, and lower spine region. OA is a multifactorial condition of joint characterised by articular cartilage loss, subchondral bone sclerosis, and inflammation leading to progressive joint degradation, structural alterations, loss of mobility and pain. Articular cartilage biology is well studied with a focus on musculoskeletal diseases and cartilage development. However, there are relatively few studies focusing on zonal changes in the cartilage during osteoarthritis.
Project description:Osteoarthritis (OA) is the most common form of arthritis worldwide. It is a complex disease affecting the whole joint but is generally characterized by progressive degradation of articular cartilage. Recent genome-wide association screens have implicated distinct DNA methylation signatures in OA patients. We show that the de novo DNA methyltransferase (Dnmt) 3b, but not Dnmt3a, is present in healthy murine and human articular chondrocytes and expression decreases in OA mouse models and in chondrocytes from human OA patients. Targeted deletion of Dnmt3b in murine articular chondrocytes results in an early onset and progressive post-natal OA-like pathology. RNA-seq and MethylC-seq analyses of Dnmt3b loss-of-function chondrocytes shows that cellular metabolic processes are affected. Specifically, TCA metabolites and mitochondrial respiration are elevated. Importantly, a chondroprotective effect was found following Dnmt3b gain-of-function in murine articular chondrocytes in vitro and in vivo. This study shows that Dnmt3b plays a significant role in regulating post-natal articular cartilage homeostasis. Cellular pathways regulated by Dnmt3b in chondrocytes may provide novel targets for therapeutic approaches to treat OA.