Gene expression in the femur hip joint articular cartilage of 12-week-old Gnptg-KO mice
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ABSTRACT: Mucolipidosis type III is a rare disease caused by mutations in the GNPTG gene, encoding the gamma-subunit of GlcNAc-1-phosphotransferase. Since osteoarthritis and joint stiffness are typical symptoms of the disease, we aimed to investigate the role of the gamma-subunit on cartilage homeostasis. We used microarray analysis to compare the global gene expression in the articular cartilage of Gnptg-KO and wild-type mice.
Project description:Mucolipidosis III gamma (MLIII) is clinically characterized by onset of first symptoms at an average of 5 years such as stiffness of hands and shoulders, claw hand deformities, scoliosis and progressive destruction of hip joints. The disease is caused by mutations in GNPTG encoding the gamma-subunit of the GlcNAc-1-phosphotransferase complex. This enzyme is responsible for the generation of mannose 6-phosphate (M6P) targeting signals on 70 soluble lysosomal enzymes that are required for their efficient receptor-mediated transport to lysosomes. In fibroblasts from Gnptg-KO mice the GlcNAc-1-phosphotransferase activity is reduced leading to low amounts of M6P-containing proteins. M6P affinity chromatography-assisted and mass spectrometry-based secretome analysis of Gnptg-KO fibroblasts revealed a distinct set of lysosomal enzymes modified with M6P residues.
Project description:Mucolipidosis III gamma (MLIII) is clinically characterized by onset of first symptoms at an average of 5 years such as stiffness of hands and shoulders, claw hand deformities, scoliosis and progressive destruction of hip joints. The disease is caused by mutations in GNPTG encoding the gamma-subunit of the GlcNAc-1-phosphotransferase complex. This enzyme is responsible for the generation of mannose 6-phosphate (M6P) targeting signals on 70 soluble lysosomal enzymes that are required for their efficient receptor-mediated transport to lysosomes. In fibroblasts from Gnptg-KO mice the GlcNAc-1-phosphotransferase activity is reduced leading to low amounts of M6P-containing proteins. M6P affinity chromatography-assisted and mass spectrometry-based secretome analysis of Gnptg-KO fibroblasts revealed a distinct set of lysosomal enzymes modified with M6P residues.
Project description:Mucolipidosis III gamma (MLIII) is clinically characterized by onset of first symptoms at an average of 5 years such as stiffness of hands and shoulders, claw hand deformities, scoliosis and progressive destruction of hip joints. The disease is caused by mutations in GNPTG encoding the gamma-subunit of the GlcNAc-1-phosphotransferase complex. This enzyme is responsible for the generation of mannose 6-phosphate (M6P) targeting signals on 70 soluble lysosomal enzymes that are required for their efficient receptor-mediated transport to lysosomes. Complementary SILAC-based lysosomal proteomics revealed decreased amounts of several lysosomal enzymes in Gnptg-KO fibroblasts involved in the degradation of lipids, glycans and proteins.
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:Groin pain is a common problem that is known to be a complex issue. The wide variety of possible pathologies in numerous anatomical structures contributes to this complexity. For patients who have anterior hip pain in Patrick's test and tenderness at Scarpa's triangle, we perform periarticular debridement based on the hypothesis that rectus femoris tendinosis, subacute/chronic fibrosis of the anterior inferior iliac spine fat pad, and gluteal muscle adhesion are responsible for such anterior hip pain. This Technical note illustrates the surgical procedure of periarticular debridement for extra-articular pathology-associated anterior hip pain. Repair of the injured labrum and correction of femoroacetabular impingement deformity have never been performed in this cohort. Arthroscopic periarticular debridement is a reliable surgical technique that can relieve anterior hip pain and provide a rapid to return to normal activities.
Project description:While prior work has established that articular cartilage arises from Prg4-expressing perichondrial cells, it is not clear how this process is specifically restricted to the perichondrium of synovial joints. We document that the transcription factor Creb5 is necessary to initiate the expression of signaling molecules that both direct the formation of synovial joints and guide perichondrial tissue to form articular cartilage instead of bone. Creb5 promotes the generation of articular chondrocytes from perichondrial precursors in part by inducing expression of Wif1, which blocks a Wnt5a autoregulatory loop in the perichondrium. Postnatal deletion of Creb5 in the articular cartilage leads to loss of both flat superficial zone articular chondrocytes coupled with a loss of both Prg4 and Wif1 expression; and a non-cell autonomous up-regulation of Ctgf. Our findings indicate that Creb5 promotes both joint formation and the subsequent development of articular chondrocytes by disrupting a Wnt5a positive-feedback loop in the perichondrium.
Project description:Full thickness articular cartilage lesions with penetration into the subchondral bone fill with fibrocartilage-like repair tissue. However, the repair tissue has compromised structural and biomechanical properties relative to normal articular cartilage. The objective of this study was to evaluate transcriptome differences between normal articular cartilage and repair tissue. Bilateral one-cm2 full-thickness lesions were made in the articular surface of the distal femurs of four adult horses followed by subchondral microfracture. Four months postoperatively, repair tissue from the lesion site and grossly normal articular cartilage from each stifle were collected. Total RNA was isolated from tissue samples, linearly amplified, and applied to a 9367-probeset equine-specific cDNA microarray. Eight paired comparisons matched by limb and horse were made with a dye-swap experimental design. Comparisons were validated by histological analysis and quantitative real-time polymerase chain reaction (qPCR). Statistical analysis revealed 3,327 (35.2%) differentially expressed probesets. Biomarkers typically associated with normal articular cartilage and fibrocartilage repair tissue corroborate earlier studies. Other changes in gene expression previously unassociated with cartilage repair were also revealed and validated by qPCR. The magnitude of divergence in transcriptional profiles between normal chondrocytes and the cells that populate repair tissue reveal substantial functional differences between these two cell populations. At the four-month postoperative time point, the relative deficiency within repair tissue of transcripts from genes which typically define articular cartilage indicate that while cells occupying the lesion might be of mesenchymal origin, they have not recapitulated differentiation to the chondrogenic phenotype of normal articular chondrocytes.
Project description:ObjectivesIt is currently poorly known how different structural and compositional components in human articular cartilage are related to their specific functional properties at different stages of osteoarthritis (OA). The objective of this study was to characterize the structure-function relationships of articular cartilage obtained from osteoarthritic human hip joints.MethodsArticular cartilage samples with their subchondral bone (n = 15) were harvested during hip replacement surgeries from human femoral necks. Stress-relaxation tests, Mankin scoring, spectroscopic and microscopic methods were used to determine the biomechanical properties, OA grade, and the composition and structure of the samples. In order to obtain the mechanical material parameters for the samples, a fibril-reinforced poroviscoelastic model was fitted to the experimental data obtained from the stress-relaxation experiments.ResultsThe strain-dependent collagen network modulus (E(f)(ε)) and the collagen orientation angle exhibited a negative linear correlation (r = -0.65, P < 0.01), while the permeability strain-dependency factor (M) and the collagen content exhibited a positive linear correlation (r = 0.56, P < 0.05). The nonfibrillar matrix modulus (E(nf)) also exhibited a positive linear correlation with the proteoglycan content (r = 0.54, P < 0.05).ConclusionThe study suggests that increased collagen orientation angle during OA primarily impairs the collagen network and the tensile stiffness of cartilage in a strain-dependent manner, while the decreased collagen content in OA facilitates fluid flow out of the tissue especially at high compressive strains. Thus, the results provide interesting and important information of the structure-function relationships of human hip joint cartilage and mechanisms during the progression of OA.
Project description:The cartilage degeneration that accompanies subchondral bone necrosis plays an important role in the development of osteonecrosis of femoral head (ONFH). To better understand the molecular basis of cartilage degradation in ONFH, we compared the proteomics profile of ONFH cartilage with that of normal controls