Project description:<p>The Osteoarthritis Initiative (OAI) is a publicly and privately funded prospective longitudinal cohort with a primary objective of identifying risk factors for incidence and progression of tibiofemoral knee OA. The OAI utilized a focused population-based recruitment to enroll 4,674 men and women between the ages of 45-79 years who either had radiographic symptomatic knee OA or who were without radiographic symptomatic OA in both knees but were considered high risk for OA because they had two or more known risk factors for knee OA. Subjects were recruited into the baseline phase of the OAI at multiple sites throughout the US between 2004 and 2006. All subjects were invited back for follow-up examinations to assess incidence or progression of OA annually, for up to 5 years.</p> <p>Phenotype data from the baseline and follow-up examinations are available for public access from the Osteoarthritis Initiative (OAI) database at <a href="http://www.oai.ucsf.edu/">http://www.oai.ucsf.edu/</a>. </p> <p>The Genetic Components of Knee Osteoarthritis (GeCKO) Study was initiated in 2009 as a genetic ancillary study to perform a genome-wide association study to identify genetic variants associated with radiographic osteoarthritis. This study included 4,482 individuals participating in the parent OAI study. Following sample cleaning (e.g., removal of duplicates, sex mismatches, poor sample quality, etc.), the final sample set included 4,129 individuals.</p>
Project description:Objective: we aimed to identify circulating microRNAs associated with fast-progressing knee osteoarthritis (OA) as compared to slow-progressing knee OA and non-progressing knee OA using sujects from the Osteoarthritis Initiative (OAI) cohort. MicroRNA libraries were prepared from plasma using the QIAseq miRNA Library Kit (QIAGEN) and sequenced on the Illumina NextSeq550 using a single-end 75-base read protocol to an average depth of 11.6 ± 2.6 SD million reads per sample.
Project description:The evolution of human bipedalism exposed the knee to unique biomechanical challenges, requiring changes in knee anatomy giving rise to the modern-day configuration. In order to better understand the relationship between derived knee morphology and the genetic factors associated with osteoarthritis risk, we performed epigenetic profiling of murine forelimb/hindlimb growth plates to identify regulatory elements shaping formation of specific knee structures, identifying signals of ancient positive selection upon which more recent genetic drift overlaps risk-associated loci. Our functional analyses of an osteoarthritis-risk variant within a reproducibly-associated locus establishes a novel model for studying this degenerative disease.
Project description:Patients with anterior cruciate ligament (ACL) tears have a significantly increased risk for developing knee osteoarthritis. These injuries often result in a knee effusion in response to the injury. Early changes in these effusions could be informative regarding initial steps in the development of post traumatic osteoarthritis. The purpose of this study was to test the hypothesis that the proteomics of knee synovial fluid changes over time following ACL injury.
Project description:Osteoarthritis is characterized by degeneration of cartilage and bone in the synovial joints. Recent findings suggest that inflammation may play a role in osteoarthritis, with synovitis being associated with the clinical symptoms of osteoarthritis. Furthermore, we have found that levels of inflammatory complement components are abnormally high in the synovial fluid of individuals with osteoarthritis. To determine whether synovial membranes could be a source of complement and other inflammatory molecules in osteoarthritic joints, we characterized the expression of genes in synovial membranes from patients with early-stage or end-stage osteoarthritis. Samples of synovial membrane were obtained from the suprapatellar pouch of patients with osteoarthritis who were treated at the Hospital for Special Surgery. Specifically, samples were from 10 patients with early-stage knee osteoarthritis who were undergoing arthroscopic procedures for degenerative meniscal tears (with documented cartilage degeneration but no full-thickness cartilage loss, Kellgren Lawrence score </=2), and from 9 patients with end-stage knee osteoarthritis ( diffuse full thickness cartilage erosion) who were undergoing total knee joint replacement. Raw data from microarray analysis of healthy synovial membranes, which were run on the same platform and array as our osteoarthritic samples, were downloaded from the NCBI Gene Expression Omnibus (accession number GSE12021) and used for comparison. The 19 new Samples of this Series were analyzed (RMA) together with 7 previously submitted healthy individual Samples (GSM175810, GSM175812, GSM176290, GSM176291, GSM176292, GSM176268, GSM176269). The complete RMA data are provided as a supplementary file on the Series record. The GSE12021 reanalyzed data are also provided as a supplementary file on the Series record. GSE32317_12genes.txt includes data from figure 1 of the paper.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.