Project description:Osteoarthritis (OA) of spine (facet joints; FJ) is one of the major causes of severe low back pain and disability worldwide. The degeneration of facet cartilage is a hallmark of FJ OA. However, endogenous mechanisms that initiate degeneration of facet cartilage are unknown and there are no disease-modifying therapies to stop FJ OA. In this study we performed microRNA array analysis to identify differentially expressed microRNAs in facet cartilage from patients with FJ OA compared to facet cartilage from patients with lumbar disc herniation (LDH).
Project description:The purpose of this study was to identify potential serum microRNA (miRNA) biomarkers of cartilage degeneration comparing preclinical mouse models of post-traumatic osteoarthritis and inflammatory arthritis.
Project description:To underly the potential downstream transcriptional regulation of HPIP that could account for cartilage and skeletal development. RNA-seq analysis were performed in HPIP knockout and control primary chondrocytes.Among the 1271 significantly differentially expressed genes, transcripts for 486 (7%) of them were upregulated while transcripts for 785 (11%) were downregulated in HPIP knockout chondrocytes compared to the controls. We found HPIP was closely correlated with the cartilage development.
Project description:To assess the direct downstream targets of HPIP, a genome-wide ChIP-seq profiling was performed. The ChIP-seq data was examined by the quality evaluation. The results demonstrated that of significant ChIP-seq peaks for HPIP, 59% of them occurred at intronic and intergenic sites We found HPIP was closely correlated with the cartilage development.
Project description:Changes in the mechanical homeostasis of the temporomandibular joint (TMJ) can lead to the initiation and progression of degenerative arthropathies such as osteoarthritis (OA). Cells sense and engage with their mechanical microenvironment through interactions with the extracellular matrix. In the mandibular condylar cartilage, the pericellular microenvironment is composed of type VI collagen. NG2/CSPG4 is a transmembrane proteoglycan that binds with type VI collagen, and has been implicated in the cell stress response through mechanical loading-sensitive signaling networks including ERK 1/2. The objective of this study is to define the role of NG2/CSPG4 in the initiation and progression of TMJ OA and to determine if NG2/CSPG4 engages ERK 1/2 in a mechanical loading dependent manner. In vivo, we induced TMJ OA in control and NG2/CSPG4 knockout mice using a surgical destabilization approach. In control mice, NG2/CSPG4 is depleted during the early stages of TMJ OA and NG2/CSPG4 knockout mice have more severe cartilage degeneration, elevated expression of key OA proteases, and suppression of OA matrix synthesis genes. In vitro, we characterized the transcriptome and protein from control and NG2/CSPG4 knockout cells and found significant dysregulation of the ERK 1/2 signaling axis. To characterize the mechanobiological response of NG2/CSPG4, we applied mechanical loads on cell-agarose-collagen scaffolds using a compression bioreactor and illustrate that NG2/CSPG4 knockout cells fail to mechanically activate ERK 1/2 and are associated with changes in the expression of the same key OA biomarkers measured in vivo. Together, these findings implicate NG2/CSPG4 in the mechanical homeostasis of TMJ cartilage and in the progression of degenerative arthropathies including OA.
Project description:Developmental dysplasia of the hip (DDH) is one of the significant risk factors for hip osteoarthritis. In order to investigate the factors that induce early articular cartilage degeneration of the hip joints that are exposed to reduced dynamic loads arising from hip dislocation , we created rodent models of hip dislocation by swaddling. Notably, expression of periostin (Postn) was increased in the acetabular articular cartilage of the DDH models; Postn was a candidate gene associated with early articular cartilage degeneration. We showed that early articular cartilage degeneration was suppressed in Postn-/- DDH mice. Furthermore, a microgravity environment induced the expression of Postn in chondrocytes through STAT3 signaling. Postn induced catabolic factors, interleukin-6 and matrix metalloproteinase 3, in articular chondrocytes through integrin-nuclear factor κB signaling. Additionally, interleukin-6 stimulated Postn expression through STAT3 signaling. Thus, Postn plays a critical role in early articular cartilage degeneration associated with hip dislocation.
Project description:The severity of osteoarthritis (OA) and cartilage degeneration are highly correlated with the development of synovitis, which is mediated by the activity of inflammatory macrophages. A better understanding of intercellular communication between inflammatory macrophages and chondrocytes should aid in the discovery of novel therapeutic targets. Here, we explored the pathological role of inflammatory macrophage-extracellular vesicles (EVs) in cartilage degeneration. Macrophages were stimulated by treatment with bacterial lipopolysaccharides to mimic the state of inflammatory macrophages and the resulting EVs (M-LPS EVs) were harvested for chondrocyte stimulation and intraarticular injection in a mouse model. This stimulation resulted in increased catabolism of chondrocytes and cartilage degeneration. Consistently, RNA-seq analyses of stimulated chondrocytes indicated that upregulated genes are mainly categorized into apoptotic process and TNF-signaling pathway which suggests the induction of apoptotic process. These chondrocytes exhibited a significant elevation in the expression of pyroptosis-related molecules that were correlated with the expression of chondrocyte catabolic factors. The disruption of caspase-11 significantly alleviated pyroptotic and catabolic processes in stimulated chondrocytes and the pathological changes in collagenase-induced OA model. Our results provide a new insight into the pathological mechanisms of OA and suggest that non-canonical pyroptosis signaling in chondrocytes represents an attractive therapeutic target for future treatment.
Project description:Articular cartilage degeneration, which may lead to osteoarthritis (OA), is a normal component of the aging process, but its underlying mechanism remains unknown. We found that chondrocytes exhibited an energy metabolism shift from glycolysis to oxidative phosphorylation (OXPHOS) during aging. Reprogrammed cartilage metabolism by parkin ablation decreased OXPHOS and increased glycolysis, with ameliorated aging-related OA. Metabolomics analysis indicated that lauroyl-L-carnitine (LLC) was decreased in aged cartilage, but increased in parkin-deficient cartilage. In vitro, LLC improved the cartilage matrix synthesis of OA chondrocytes. In vivo, intraarticular injection of LLC in mice with anterior cruciate ligament transaction (ACLT) ameliorated OA. These results suggest that metabolic changes are regulated by parkin-impaired cartilage during aging, and targeting the metabolomic changes by supplementation with LLC is a promising treatment strategy for ameliorating OA.
Project description:Articular cartilage degeneration, which may lead to osteoarthritis (OA), is a normal component of the aging process, but its underlying mechanism remains unknown. We found that chondrocytes exhibited an energy metabolism shift from glycolysis to oxidative phosphorylation (OXPHOS) during aging. Reprogrammed cartilage metabolism by parkin ablation decreased OXPHOS and increased glycolysis, with ameliorated aging-related OA. Metabolomics analysis indicated that lauroyl-L-carnitine (LLC) was decreased in aged cartilage, but increased in parkin-deficient cartilage. In vitro, LLC improved the cartilage matrix synthesis of OA chondrocytes. In vivo, intraarticular injection of LLC in mice with anterior cruciate ligament transaction (ACLT) ameliorated OA. These results suggest that metabolic changes are regulated by parkin-impaired cartilage during aging, and targeting the metabolomic changes by supplementation with LLC is a promising treatment strategy for ameliorating OA.
Project description:Osteoarthritis (OA) is a chronic degenerative disease that leads to joint failure with pain and disability. Gene regulations are implicated in driving an imbalance between the expression of catabolic and anabolic factors, leading eventually to osteoarthritic cartilage degeneration. The different stages of disease progression are described by the complex pattern of transcriptional regulations. The dynamics in pattern alterations were monitored in each individual animal during the time-course of OA progression.