Galectin-1 couples glycobiology to inflammation in osteoarthritis through the activation of an NF-κB-regulated gene network
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ABSTRACT: Osteoarthritis is a degenerative joint disease that ranks among the leading causes of pain, adult disability, shortening of working life, and socioeconomic costs worldwide. The mechanisms underlying osteoarthritis pathogenesis are yet to be fully elucidated, thus limiting current disease management and treatment. Galectin-1 is an endogenous carbohydrate-binding protein central to adhesion via glycan-bridging, glycoconjugate-mediated signaling, cell proliferation, differentiation, apoptosis, cancers, and host-pathogen interactions. The chondrocyte glycophenotype, which can act as a system of counter-receptors for galectin binding, is compromised in osteoarthritis. We here investigated Galectin-1 and associated gene network's role in human osteoarthritis pathogenesis. Immunohistochemical analysis showed that Galectin-1 associates with osteoarthritic cartilage and subchondral bone histopathology and severity (p<0.0001, n=29 patients). Glycan-dependent Galectin-1 binding to osteoarthritic chondrocytes' cell surface led to marked upregulation of matrix metalloproteinases and activation of NF-κB. Biochemical, molecular and genome-wide analyses showed that Galectin-1 strongly activates a large inflammatory gene network (p<10-16). Bioinformatic analyses of gene promoters up-regulated by Galectin-1 unveiled an overwhelming NF-κB signaling signature. Inhibition of any of several components of the NF-κB pathway using dedicated inhibitors led to dose-dependent impairment of Galectin-1-mediated transcriptional activation. This study identifies for the first time Galectin-1 as an activator of clinically relevant inflammatory-response genes co-regulated by NF-κB. Since inflammation is critical to cartilage degeneration in osteoarthritis, this report is also first to put glycobiology at the center-stage of osteoarthritic cartilage degeneration. Finally, this is the first report to uncover a Galectin-1 gene signature and associated gene network in any biological setting or species. For microarray experiments, osteoarthritic chondrocytes were isolated from five male patients (47-78 years). Following starvation, cells were incubated in the presence of 50 µg/ml recombinant Galectin-1 for 24 h. For each donor population, untreated cells were included as control. In total, 10 samples were analyzed.
ORGANISM(S): Homo sapiens
SUBMITTER: Markus Jeitler
PROVIDER: E-GEOD-68760 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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