Expression of CD44 in human neoplastic and normal hyaline cartilage (original) (raw)
Related papers
International journal of molecular medicine, 2009
The purpose of this study was to investigate the expression of different CD44 and hyaluronan synthase isoforms in cartilage, their alterations during the chondrocyte dedifferentiation process in monolayer culture and during the redifferentiation process on 3D scaffolds. Chondrocytes isolated from human articular cartilage were cultured as a monolayer for up to 36 days and were seeded on two different 3D scaffolds (HYAFF 11 and Bio-Gide). Expression levels of CD44s, CD44-lt, CD44-st, HAS1, HAS2, HAS3 and UDPGD were determined by real-time RT-PCR at different time points. At the protein level CD44 and CD90 were analyzed by flow cytometry. HAS2 was found to be the predominantly expressed hyaluronan synthase in chondrocytes and was not subjected to any regulation during the dedifferentiation process. CD44s, CD44-lt, CD44-st and UDPGD, however, were upregulated immediately after cell isolation. In addition, a high cell density was found to significantly increase CD44-st and CD44-lt expre...
Histopathology, 1997
Histopathology 31, 451-459 CD44 expression is up-regulated in the deep zone of osteoarthritic cartilage from human femoral heads Aims: The objective of this study was to detail the topographical and zonal distribution of the cell adhesion molecule CD44 in normal and osteoarthritic cartilage. Methods and results: Immunohistochemistry utilizing well characterized anti-CD44 antibodies (clones A3D8, Bric 235, 2C5) was performed on cryostat and paraffin sections of human articular cartilage from macroscopically normal (n ¼ 18) and osteoarthritic (n ¼ 11) femoral heads. Samples for cryostat sections were obtained from 12 topographically different sites. Sections were divided into zones (superficial, middle, deep) and the CD44 staining scored. Chondrocytes in normal articular cartilage and cartilage from osteoarthritic femoral heads stained positive for CD44 in both cryostat and paraffin sections. Normal cartilage showed a significant decrease in CD44 staining in the deep zone as compared to the superficial zone (P < 0.05). However, cryostat sections of residual cartilage from osteoarthritic femoral heads showed increased CD44 staining in the deep zone as compared to normal articular cartilage. The CD44 staining showed no topographical variation in either the normal cartilage or the osteoarthritic residual cartilage. Conclusions: CD44 expression displays a distinct zonal variation in normal articular cartilage which is lost in osteoarthritic cartilage due to an up-regulated expression in the deep zone. CD44 expression does not exhibit topographical variation.
Arthritis & Rheumatism, 2003
Objective. To investigate the mechanism of induction of matrix metalloproteinases (MMPs) by a 40-kd COOH-terminal heparin-binding fibronectin fragment (HBFN-f) containing III12-14 and IIICS domains in human articular cartilage in culture. Methods. Human articular cartilage was removed from macroscopically normal femoral heads and cultured with HBFN-f. MMP secretion into conditioned media was analyzed by immunoblotting (MMPs 1 and 13) and by gelatin zymography (MMPs 2 and 9). Type II collagen cleavage by collagenase was monitored in culture by immunoassay. Involvement of specific peptidebinding domains in HBFN-f and the involvement of CD44 were assessed with synthetic peptides and an anti-CD44 antibody. Immunofluorescence histochemistry was performed using fluorescein isothiocyanateconjugated anti-CD44 antibody. Results. HBFN-f stimulated production of MMPs 1, 2, 9, and 13 in association with type II collagen cleavage by collagenase in human articular cartilage. Peptide V (WQPPRARI) of HBFN-f, which can bind cell surface heparan sulfate proteoglycan (HSPG), blocked MMP induction by HBFN-f, while the scrambled peptide V (RPQIPWAR) had no effect. Peptide CS-1 of 25 amino acids in IIICS of HBFN-f caused no significant effect. Treatment of cartilage with anti-CD44 antibody or HSPG resulted in significant inhibition of HBFN-fstimulated MMP production. Preincubation with peptide V blocked binding of the anti-CD44 antibody to chondrocytes in cartilage. Conclusion. Interaction of the peptide V sequence in HBFN-f with glycosaminoglycans, such as those in CD44, plays an important role in HBFN-f-stimulated MMP production in articular cartilage. Because CD44 is up-regulated in osteoarthritic and rheumatoid arthritic cartilage, the role of the interaction between CD44 and HBFN-f in these pathologies should be of relevance and should be studied further.
Identification of CD44 Residues Important for Hyaluronan Binding and Delineation of the Binding Site
Journal of Biological Chemistry, 1998
CD44 is a widely distributed cell surface protein that plays a role in cell adhesion and migration. As a proteoglycan, CD44 is also implicated in growth factor and chemokine binding and presentation. The extracellular region of CD44 is variably spliced, giving rise to multiple CD44 isoforms. All isoforms contain an amino-terminal domain, which is homologous to cartilage link proteins. The cartilage link protein-like domain of CD44 is important for hyaluronan binding. The structure of the link protein domain of TSG-6 has been determined by NMR. Based on this structure, a molecular model of the linkhomologous region of CD44 was constructed. This model was used to select residues for site-specific mutagenesis in an effort to identify residues important for ligand binding and to outline the hyaluronan binding site. Twentyfour point mutants were generated and characterized, and eight residues were identified as critical for binding or to support the interaction. In the model, these residues form a coherent surface the location of which approximately corresponds to the carbohydrate binding sites in two functionally unrelated calcium-dependent lectins, mannose-binding protein and E-selectin (CD62E).
Molecular mechanisms regulating the hyaluronan binding activity of the adhesion protein CD44
Journal of Neuro-Oncology, 1995
In the present study, we describe the isolation and characterization of a cDNA clone designated B6F1.3, that appears to 'activate' the hyaluronan-binding capacity of CD44 upon transfection into the murine fibroblastoid cell line MOP8. Sequence analysis indicates that the putative regulatory molecule encoded by this clone is identical to the murine interleukin-2 receptor ? chain (mIL-2Ry), a recently described type i transmembrane protein that constitutes an integral component of the cell surface receptors that bind a number of cytokines including IL-2, IL-4, IL-7, IL-9, IL-15 and perhaps also IL-13. Mutations in this molecule have been shown to be responsible for X-linked severe combined immunodeficiency (XSCID) in humans. With the exception of bone marrow, the mIL-2Ry chain was found to be expressed at high levels on all hemopoietic cell lines and tissue types examined. Non-hemopoietic tissues are generally negative. FACS analysis and Western blot analysis indicated respectively that B6F1.3 does not mediate its effects by upregulating the expression of CD44 or by altering the alternative splicing of the molecule. Removal of the cytoplasmic tail of the mIL-2R? chain, including a Src homology region 2 (SH2) subdomain, abolished its ability to enhance CD44-mediated binding to hyaluronan suggesting the involvement of signal transduction events triggered via the cytoplasmic domain in the 'activation' process. Determining whether activating molecules such as B6F1.3 are co-expressed within tumor cells may help improve the potential value of CD44 as a diagnostic marker of metastatic disease.
Neoplasia, 1999
Soluble CD44 proteins generated by proteolytic cleavage or aberrant intron retention have been shown to antagonize the ligand binding activity of the corresponding cell surface receptor, inducing apoptosis and inhibiting tumor growth. Interestingly, such findings appear to contradict recent studies demonstrating a correlation between the presence of high levels of soluble CD44 in the serum of cancer patients and poor prognosis. In the present study, we report the cloning of a novel, naturally occurring, differentially expressed, soluble CD44 isoform, designated CD44RC, which, in contrast to previously described soluble CD44 proteins, can dramatically enhance the hyaluronan binding activity of cell surface CD44. Sequence analysis suggests that CD44RC is generated by an alternative splicing event in which the 3 H end of CD44 exon 2 is spliced into an internal splice acceptor site present within exon 18, altering reading frame and giving rise to a soluble protein with a unique COOH terminus. Functional studies suggest that CD44RC enhances hyaluronan binding by adhering to chondroitin sulfate side-chains attached to cell surface CD44, generating a multivalent complex with increased avidity for hyaluronan.
CD44 binds a chondroitin sulfate proteoglycan, aggrecan
International Immunology, 2001
Here we report that CD44 binds a chondroitin sulfate (CS) proteoglycan, aggrecan, a major component of cartilage. Soluble CD44-IgG and CD44 ⍣ cells bound to aggrecan from rat chondrosarcoma and bovine cartilage, immobilized on microtiter plates. In both cases, binding was blocked by a neutralizing anti-CD44 mAb or by the pretreatment of aggrecan with chondroitinase, but not hyaluronidase or keratanase, indicating that CD44 binds aggrecan in a manner dependent on CS side chains of aggrecan and that hyaluronic acid is not involved in the binding. Structural analysis showed that glycosaminoglycans of aggrecan from rat chondrosarcoma and bovine articular cartilage consist of mainly CS A and a mixture of CS A and C respectively. When immobilized on microtiter plates, both CS A and C bound CD44-IgG, and the reaction was specifically inhibited by an anti-CD44 mAb. In addition, aggrecan augmented apoptosis in cells expressing CD44-Fas chimeric molecules in synergy with a non-blocking anti-CD44 mAb IRAWB14.4, suggesting that CD44-aggrecan interaction can induce oligomerization of the chimeric molecules. These results suggest that aggrecan interacts with CD44 to mediate cell adhesion and to trigger oligomerization of CD44 molecules, which may lead to intracellular signaling.
Cytokines regulate the affinity of soluble CD44 for hyaluronan
FEBS Letters, 2004
CD44, a receptor for the extracellular matrix glycosaminoglycan hyaluronan, has been implicated in many adhesion-dependent cellular processes including tumor growth and metastasis. Soluble CD44 has been identi¢ed in the serum of normal individuals. Furthermore, tumor progression is often associated with marked increases in plasma levels of soluble CD44. Release of soluble CD44 by proteolytic cleavage (shedding) of membrane-anchored CD44 is likely to alter cellular responses to the environment due to modi¢cation of the cell surface and the potential for soluble CD44 to in£uence CD44mediated hyaluronan binding to cell surfaces. Cellular activation is typically required to induce hyaluronan binding to cell surface CD44 but the a⁄nity of endogenous soluble CD44 for hyaluronan remains unknown. In this study, we demonstrate that oncostatin M and transforming growth factor L L1 (TGF-L L1) which stimulate hyaluronan binding to HTB58 lung epithelial-derived tumor cells, also induce the release of soluble CD44. Interestingly, soluble CD44 released by oncostatin M-treated cells retained the ligand-binding properties of the membrane-anchored receptor. In contrast, soluble CD44 released from TGF-L L1treated HTB58 cells di¡ered in its hyaluronan-binding capacity from cell surface CD44 expressed on TGF-L L1-stimulated cells. These data indicate that the mechanisms that regulate the generation of soluble CD44 may also govern the binding of the released receptor to hyaluronan and therefore determine the impact on CD44-dependent physiologic and pathologic processes. .pl (J. Cichy).
Hyaluronan and CD44 control of cell fate
2016
Fibrosis can be charactorised as abberent wound healing resulting from an increased presence of α-smooth muscle actin (αSMA)-rich, myofibroblasts and a continued influx of immune cell mediators. The pro-fibrotic and pro-inflammatory cytokines TGF-β1 and IL-1β, respectivley, have been implicated in fibrotic progression by activating hyaluronan (HA)/CD44-mediated pathways. CD44, the principal HA receptor, exists as multiple spliced variants which mediate multiple celluar functions through their association with HA. The aim of this Thesis was to investigate the expression and interactions of CD44 variants asociated with fibroblast activation induced by TGF-β1 or IL-1β. Multiple forms of CD44 spliced variants were identified in fibroblasts. Stimulation with TGF-β1 decreased the expression of all variants, whereas IL-1β-increased global CD44 expression. CD44s was the variant identified as essential for both TGF-β1 induction of myofibroblasts and IL-1β-induced monocyte binding to fibrobla...