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Alan C. Rapraeger - One of the best experts on this subject based on the ideXlab platform.
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Syndecan 1 and Syndecan 4 capture epidermal growth factor receptor family members and the α3β1 integrin via binding sites in their ectodomains novel synstatins prevent kinase capture and inhibit α6β4 integrin dependent epithelial cell motility
Journal of Biological Chemistry, 2015Co-Authors: Haiyao Wang, Alan C. RapraegerAbstract:Abstract The α6β4 integrin is known to associate with receptor tyrosine kinases when engaged in epithelial wound healing and in carcinoma invasion and survival. Prior work has shown that HER2 associates with α6β4 integrin and Syndecan-1 (Sdc1), in which Sdc1 engages the cytoplasmic domain of the β4 integrin subunit allowing HER2-dependent motility and carcinoma cell survival. In contrast, EGFR associates with Sdc4 and the α6β4 integrin, and EGFR-dependent motility depends on cytoplasmic engagement of β4 integrin with Sdc4. However, how HER2 and EGFR assimilate into a complex with the Syndecans and integrin, and why kinase capture is Syndecan-specific has remained unknown. In the present study, we demonstrate that HER2 is captured via a site, comprised of amino acids 210-240, in the extracellular domain of human Sdc1, and EGFR is captured via an extracellular site comprised of amino acids 87-131 in human Sdc4. Binding assays using purified recombinant proteins demonstrates that the interaction between the EGFR family members and the Syndecans is direct. The α3β1 integrin, which is responsible for the motility of the cells, is captured at these sites as well. Peptides based on the interaction motifs in Sdc1 and Sdc4, called synstatins (SSTN210-240 and SSTN87-131) competitively displace the receptor tyrosine kinase and α3β1 integrin from the Syndecan with an IC50 of 100-300 nM. The Syndecans remain anchored to the α6β4 integrin via its cytoplasmic domain, but the activation of cell motility is disrupted. These novel SSTN peptides are potential therapeutics for carcinomas that depend on these HER2- and EGFR-coupled mechanism for their invasion and survival.
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cytoplasmic domain interactions of Syndecan 1 and Syndecan 4 with α6β4 integrin mediate human epidermal growth factor receptor her1 and her2 dependent motility and survival
Journal of Biological Chemistry, 2014Co-Authors: Haiyao Wang, Deannalee M Beauvais, Alan C. RapraegerAbstract:Epithelial cells are highly dependent during wound healing and tumorigenesis on the α6β4 integrin and its association with receptor tyrosine kinases. Previous work showed that phosphorylation of the β4 subunit upon matrix engagement depends on the matrix receptor Syndecan (Sdc)-1 engaging the cytoplasmic domain of the β4 integrin and coupling of the integrin to human epidermal growth factor receptor-2 (HER2). In this study, HER2-dependent migration activated by matrix engagement is compared with migration stimulated by EGF. We find that whereas HER2-dependent migration depends on Sdc1, EGF-dependent migration depends on a complex consisting of human epidermal growth factor receptor-1 (HER1, commonly known as EGFR), α6β4, and Sdc4. The two Syndecans recognize distinct sites at the extreme C terminus of the β4 integrin cytoplasmic domain. The binding motif in Sdc1 is QEEXYX, composed in part by its Syndecan-specific variable (V) region and in part by the second conserved (C2) region that it shares with other Syndecans. A cell-penetrating peptide containing this sequence competes for HER2-dependent epithelial migration and carcinoma survival, although it is without effect on the EGFR-stimulated mechanism. β4 mutants bearing mutations specific for Sdc1 and Sdc4 recognition act as dominant negative mutants to block cell spreading or cell migration that depends on HER2 or EGFR, respectively. The interaction of the α6β4 integrin with the Syndecans appears critical for it to be utilized as a signaling platform; migration depends on α3β1 integrin binding to laminin 332 (LN332; also known as laminin 5), whereas antibodies that block α6β4 binding are without effect. These findings indicate that specific Syndecan family members are likely to have key roles in α6β4 integrin activation by receptor tyrosine kinases.
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synstatin a selective inhibitor of the Syndecan 1 coupled igf1r αvβ3 integrin complex in tumorigenesis and angiogenesis
FEBS Journal, 2013Co-Authors: Alan C. RapraegerAbstract:The Syndecans are a family of heparan-sulfate-decorated cell surface proteoglycans, matrix receptors with roles in cell adhesion and growth factor signaling. Their heparan sulfate chains recognize “heparin-binding” motifs ubiquitously present in the extracellular matrix (ECM), providing the means for Syndecans to constitutively bind and cluster to sites of cell-matrix adhesion. Emerging evidence suggests that specialized docking sites in the Syndecan extracellular domains may serve to localize other receptors to these sites as well, including integrins and growth factor receptor tyrosine kinases. A prototypic example of this mechanism is the capture of the αvβ3 integrin and insulin-like growth factor-1 receptor (IGF1R) by Syndecan-1 (Sdc1) – forming a ternary receptor complex in which signaling downstream of IGF1R activates the integrin. This Sdc1-coupled ternary receptor complex is especially prevalent on tumor cells and activated endothelial cells undergoing angiogenesis, reflecting the upregulated expression of αvβ3 integrin in such cells. As such, much effort has focused on developing therapeutics that target this integrin in various cancers. Along these lines, the site in the Sdc1 ectodomain responsible for capture and activation of the αvβ3 or αvβ5 integrins by IGF1R can be mimicked by a short peptide called “synstatin” (SSTN), which competitively displaces the integrin and IGF1R kinase from the Syndecan and inactivates the complex. This review summarizes our current knowledge of the Sdc1-coupled ternary receptor complex and the efficacy of SSTN as an emerging therapeutic to target this signaling mechanism.
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The Syndecan-1 ectodomain regulates αvβ3 integrin activity in human mammary carcinoma cells
Journal of Cell Biology, 2004Co-Authors: Deannalee M Beauvais, Brandon J. Burbach, Alan C. RapraegerAbstract:The αvβ3 integrin participates in cell morphogenesis, growth factor signaling, and cell survival. Activation of the integrin is central to these processes and is influenced by specific ECM components, which engage both integrins and Syndecans. This paper demonstrates that the αvβ3 integrin and Syndecan-1 (S1) are functionally coupled. The integrin is dependent on the Syndecan to become activated and to mediate signals required for MDA-MB-231 and MDA-MB-435 human mammary carcinoma cell spreading on vitronectin or S1-specific antibody. Coupling of the Syndecan to αvβ3 requires the S1 ectodomain (ED), as ectopic expression of glycosylphosphatidylinositol-linked S1ED enhances αvβ3 recognition of vitronectin; and treatments that target this domain, including competition with recombinant S1ED protein or anti-S1ED antibodies, mutation of the S1ED, or down-regulation of S1 expression by small-interfering RNAs, disrupt αvβ3-dependent cell spreading and migration. Thus, S1 is likely to be a critical regulator of many cellular behaviors that depend on activated αvβ3 integrins.
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Syndecan 1 mediated cell spreading requires signaling by αvβ3 integrins in human breast carcinoma cells
Experimental Cell Research, 2003Co-Authors: Deannalee M Beauvais, Alan C. RapraegerAbstract:Abstract Syndecans are cell surface heparan sulfate proteoglycans with regulatory roles in cell adhesion, proliferation, and differentiation [Annu. Rev. Biochem. 68 (1999) 729]. While the Syndecan heparan sulfate chains are essential for matrix binding, less is known about the signaling role of their core proteins. To mimic Syndecan-specific adhesion, MDA-MB-231 mammary carcinoma cells were plated on antibodies against Syndecan-4 or Syndecan-1. While cells adherent via Syndecan-4 spread, cells adherent via Syndecan-1 do not. However, cells adherent via Syndecan-1 can be induced to spread by Mn2+, suggesting that activation of a β1 or β3 integrin partner is required. Surprisingly, pretreatment of cells with a function-activating β1 antibody does not induce spreading, whereas function-blocking β1 integrin antibodies do, suggesting involvement of a β1-to-β3 integrin cross-talk. Indeed, blockade of β1 integrin activation induces αvβ3 integrin activation detectable by soluble fibrinogen binding. Spreading in response to Syndecan-1 is independent of integrin-ligand binding. Furthermore, competition with soluble murine Syndecan-1 ectodomain, which does not disrupt cell adhesion, nonetheless blocks the spreading mechanism. These data suggest that the ectodomain of the Syndecan-1 core protein directly participates in the formation of a signaling complex that signals in cooperation with αvβ3 integrins; signaling via this complex is negatively regulated by β1 integrins.
John R Couchman - One of the best experts on this subject based on the ideXlab platform.
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cell surface heparan sulfate proteoglycans control adhesion and invasion of breast carcinoma cells
Molecular Cancer, 2015Co-Authors: Hinke A B Multhaupt, Hooi Ching Lim, John R CouchmanAbstract:Background Cell surface proteoglycans interact with numerous regulators of cell behavior through their glycosaminoglycan chains. The Syndecan family of transmembrane proteoglycans are virtually ubiquitous cell surface receptors that are implicated in the progression of some tumors, including breast carcinoma. This may derive from their regulation of cell adhesion, but roles for specific Syndecans are unresolved.
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mapping of matrix metalloproteinase cleavage sites on Syndecan 1 and Syndecan 4 ectodomains
FEBS Journal, 2013Co-Authors: Tina Manonjensen, Hinke A B Multhaupt, John R CouchmanAbstract:Syndecans are transmembrane heparan sulfate proteoglycans with roles in cell proliferation, differentiation, adhesion, and migration. They have been associated with multiple functions in tumour progression, through their ability to interact with a wide range of ligands as well as other receptors, which makes them key effectors in the pericellular microenvironment. Extracellular shedding of Syndecans by tumour-associated matrix metalloproteinases (MMPs) may have an important role in tumour progression. Such ectodomain shedding generates soluble ectodomains that may function as paracrine or autocrine effectors, or as competitive inhibitors of the intact proteoglycan. Tumour-associated MMPs are shown here to cleave the ectodomains of human Syndecan-1 and Syndecan-4. Two membrane proximal regions of both Syndecan-1 and Syndecan-4 are favoured MMP cleavage sites, six and 15 residues from the transmembrane domain. Other sites are 35–40 residues C-terminal from the heparan sulfate chain substitution sites in both Syndecans. The MT1-MMP cleavage sites in Syndecan-1 and Syndecan-4 were confirmed by site-directed mutagenesis. These findings provide insights into the characteristics of Syndecan shedding.
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Syndecan 1 and Syndecan 4 are independent indicators in breast carcinoma
Journal of Histochemistry and Cytochemistry, 2011Co-Authors: Maria Elisabeth Lendorf, Hinke A B Multhaupt, Tina Manonjensen, Pauliina Kronqvist, John R CouchmanAbstract:Syndecan proteoglycans may be key regulators of tumor invasion and metastasis because this four-member family of transmembrane receptors regulates cell adhesion, proliferation, and differentiation. Their expression can also serve as prognostic markers. In breast carcinomas, Syndecan-1 overexpression correlates with poor prognosis and aggressive phenotype. Syndecan-4 is expressed in most breast carcinoma cell lines, but its role in malignancy is unclear. A possible relationship between Syndecan-1 and Syndecan-4 expression and established prognostic factors in breast carcinomas was examined. Duplicate samples of 114 benign and malignant breast disease cases were stained for the two Syndecans. Clinicopathological information was available for all cases. Syndecan-1 was detected in 72.8% of cases, with significant association between its expression and histological tumor type (p<0.05) and high grade tumors (p<0.05). Syndecan-4 was expressed in 66.7% of cases; expression correlated significantly with positive estrogen (p<0.01) and progesterone (p<0.01) receptor status. Independent expression of the two Syndecans was noted from an analysis of single and double positive cases. There was a statistical relationship between Syndecan-1 presence in high-grade tumors and absence of Syndecan-4, whereas Syndecan-4 presence in cases positive for estrogen and progesterone receptor associated with Syndecan-1 absence. These Syndecans may, therefore, have distinct roles in regulating breast carcinoma cell behavior.
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proteoglycans in health and disease the multiple roles of Syndecan shedding
FEBS Journal, 2010Co-Authors: Tina Manonjensen, Yoshifumi Itoh, John R CouchmanAbstract:Proteolytic processes in the extracellular matrix are a major influence on cell adhesion, migration, survival, differentiation and proliferation. The Syndecan cell-surface proteoglycans are important mediators of cell spreading on extracellular matrix and respond to growth factors and other biologically active polypeptides. The ectodomain of each Syndecan is constitutively shed from many cultured cells, but is accelerated in response to wound healing and diverse pathophysiological events. Ectodomain shedding is an important regulatory mechanism, because it rapidly changes surface receptor dynamics and generates soluble ectodomains that can function as paracrine or autocrine effectors, or competitive inhibitors. It is known that the family of Syndecans can be shed by a variety of matrix proteinase, including many metzincins. Shedding is particularly active in proliferating and invasive cells, such as cancer cells, where cell-surface components are continually released. Here, recent research into the shedding of Syndecans and its physiological relevance are assessed.
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Syndecans in wound healing inflammation and vascular biology
The International Journal of Biochemistry & Cell Biology, 2007Co-Authors: Annika N Alexopoulou, Hinke A B Multhaupt, John R CouchmanAbstract:Syndecans are heparan sulphate proteoglycans consisting of a type I transmembrane core protein modified by heparan sulphate and sometimes chondroitin sulphate chains. They are major proteoglycans of many organs including the vasculature, along with glypicans and matrix proteoglycans. Heparan sulphate chains have potential to interact with a wide array of ligands, including many growth factors, cytokines, chemokines and extracellular matrix molecules relevant to growth regulation in vascular repair, hypoxia, angiogenesis and immune cell function. This is consistent with the phenotypes of Syndecan knock-out mice, which while viable and fertile, show deficits in tissue repair. Furthermore, there are potentially important changes in Syndecan distribution and function described in a variety of human vascular diseases. The purpose of this review is to describe Syndecan structure and function, consider the role of Syndecan core proteins in transmembrane signalling and also their roles as co-receptors with other major classes of cell surface molecules. Current debates include potential redundancy between Syndecan family members, the significance of multiple heparan sulphate interactions, regulation of the cytoskeleton and cell behaviour and the switch between promoter and inhibitor of important cell functions, resulting from protease-mediated shedding of Syndecan ectodomains.
Thomas H Barker - One of the best experts on this subject based on the ideXlab platform.
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dynamic catch of a thy 1 α5β1 Syndecan 4 trimolecular complex
Nature Communications, 2014Co-Authors: Vincent F Fiore, Lining Ju, Yunfeng Chen, Thomas H BarkerAbstract:Molecular details of the synergy between integrins and Syndecans are poorly understood. Here, Fiore et al. show that Syndecan-4 and α5β1 integrin form a trimolecular complex with Thy-1 that exhibits ‘dynamic catch’ behaviour, in which force strengthens the synergistic binding and modulates signalling at the focal adhesion level.
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dynamic catch of a thy 1 α5β1 Syndecan 4 trimolecular complex
Nature Communications, 2014Co-Authors: Vincent F Fiore, Yunfeng Chen, Cheng Zhu, Thomas H BarkerAbstract:Cancer cell adhesion to the vascular endothelium is a critical step of tumour metastasis. Endothelial surface molecule Thy-1 (CD90) is implicated in the metastatic process through its interactions with integrins and Syndecans. However, how Thy-1 supports cell-cell adhesion in a dynamic mechanical environment is not known. Here we show that Thy-1 supports β1 integrin- and Syndecan-4 (Syn4)-mediated contractility-dependent mechanosignalling of melanoma cells. At the single-molecule level, Thy-1 is capable of independently binding α5β1 integrin and Syndecan-4 (Syn4) receptors. However, in the presence of both α5β1 and Syn4, the two receptors bind cooperatively to Thy-1, to form a trimolecular complex. This trimolecular complex displays a unique phenomenon we coin 'dynamic catch', characterized by abrupt bond stiffening followed by the formation of catch bonds, where force prolongs the bond lifetime. Thus, we reveal a new class of trimolecular interactions where force strengthens the synergistic binding of two co-receptors and modulates downstream mechanosignalling.
Ofer Reizes - One of the best experts on this subject based on the ideXlab platform.
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Mice lacking the Syndecan-3 gene are resistant to diet-induced obesity
2020Co-Authors: April D. Strader, Stephen C. Benoit, Ofer Reizes, Stephen C. Woods, Randy J. SeeleyAbstract:The accurate matching of caloric intake to caloric expenditure involves a complex system of peripheral signals and numerous CNS neurotransmitter systems. Syndecans are a family of membrane-bound heparan sulfate proteoglycans that modulate ligand-receptor interactions. Syndecan-3 is heavily expressed in several areas of the brain, including hypothalamic nuclei, which are known to regulate energy balance. In particular, Syndecans have been implicated in modulation of the activity of the melanocortin system, which potently regulates energy intake, energy expenditure, and peripheral glucose metabolism. Our data demonstrate that Syndecan-3-null mice have reduced adipose content compared with wild-type mice. On a high-fat diet, Syndecan-3-null male and female mice exhibited a partial resistance to obesity due to reduced food intake in males and increased energy expenditure in females relative to that of wild-type mice. As a result, Syndecan-3-null mice on a high-fat diet accumulated less adipose mass and showed improved glucose tolerance compared with wild-type controls. The data implicate Syndecan-3 in the regulation of body weight and suggest that inhibition of Syndecan-3 may provide a therapeutic approach for the treatment of obesity resulting from exposure to high-fat diets. Introduction Body adipose mass is regulated by matching caloric intake to caloric expenditure over time. The CNS is a critical site where signals of adipose stores are sensed and where appropriate changes in intake and/or expenditure are produced. Over the past decade, a number of proteins have been implicated in the process of sensing peripheral fuel status and the effector mechanisms that defend peripheral adipose mass (1). While most of these proteins are neurotransmitters, receptors, or intracellular signaling molecules, recent data indicate an important role for a unique family of proteins called Syndecans. Syndecans are ubiquitous cell surface heparan sulfate proteoglycans (HSPGs; proteins with covalently attached, highly acidic sugar chains), unique in their ability to bind many extracellular peptides, such as hormones and growth factors. Syndecans are found on almost every cell type (2) but are differentially expressed depending on the tissue type. Evidence for the involvement of Syndecans in the control of energy balance comes from mice that overexpress Syndecan-1 (3). Despite using the pan-selective cytomegalovirus promoter enhancer, Reizes and colleagues showed that mice overexpressing Syndecan-1 express transgenic Syndecan-1 in a highly unique and circumscribed pattern including expression in regions of the hypothalamus that have long been linked to energy balance regulation, such as the paraventricular nucleus (3, 4). Quite unexpectedly, these mice also show a profound, maturity-onset obesity and type 2 diabetes (3). Although such data indicate a potential role for Syndecans in the CNS control of energy balance, Syndecan-1 is not normally expressed in the CNS. However, other members of the Syndecan family are expressed in the CNS and, most nota
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Syndecan 3 is selectively pro inflammatory in the joint and contributes to antigen induced arthritis in mice
Arthritis Research & Therapy, 2014Co-Authors: Oksana Kehoe, Jim Middleton, Ofer Reizes, Andrew D. Eustace, Sophie King, Neena Kalia, Charlotte Boyes, Anwen Sian Williams, Angela Margaret PattersonAbstract:Syndecans are heparan sulphate proteoglycans expressed by endothelial cells. Syndecan-3 is expressed by synovial endothelial cells of rheumatoid arthritis (RA) patients where it binds chemokines, suggesting a role in leukocyte trafficking. The objective of the current study was to examine the function of Syndecan-3 in joint inflammation by genetic deletion in mice and compare with other tissues. Chemokine C-X-C ligand 1 (CXCL1) was injected in the joints of Syndecan-3−/−and wild-type mice and antigen-induced arthritis performed. For comparison chemokine was administered in the skin and cremaster muscle. Intravital microscopy was performed in the cremaster muscle. Administration of CXCL1 in knee joints of Syndecan-3−/−mice resulted in reduced neutrophil accumulation compared to wild type. This was associated with diminished presence of CXCL1 at the luminal surface of synovial endothelial cells where this chemokine clustered and bound to heparan sulphate. Furthermore, in the arthritis model Syndecan-3 deletion led to reduced joint swelling, leukocyte accumulation, cartilage degradation and overall disease severity. Conversely, CXCL1 administration in the skin of Syndecan-3 null mice provoked increased neutrophil recruitment and was associated with elevated luminal expression of E-selectin by dermal endothelial cells. Similarly in the cremaster, intravital microscopy showed increased numbers of leukocytes adhering and rolling in venules in Syndecan-3−/−mice in response to CXCL1 or tumour necrosis factor alpha. This study shows a novel role for Syndecan-3 in inflammation. In the joint it is selectively pro-inflammatory, functioning in endothelial chemokine presentation and leukocyte recruitment and cartilage damage in an RA model. Conversely, in skin and cremaster it is anti-inflammatory.
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Syndecan-3 is selectively pro-inflammatory in the joint and contributes to antigen-induced arthritis in mice
Arthritis Research & Therapy, 2014Co-Authors: Oksana Kehoe, Ofer Reizes, Andrew D. Eustace, Sophie King, Neena Kalia, Charlotte Boyes, Anwen Sian Williams, Angela Margaret Patterson, Jim MiddletonAbstract:Introduction Syndecans are heparan sulphate proteoglycans expressed by endothelial cells. Syndecan-3 is expressed by synovial endothelial cells of rheumatoid arthritis (RA) patients where it binds chemokines, suggesting a role in leukocyte trafficking. The objective of the current study was to examine the function of Syndecan-3 in joint inflammation by genetic deletion in mice and compare with other tissues.
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The role of Syndecans in the regulation of body weight and synaptic plasticity.
The International Journal of Biochemistry & Cell Biology, 2008Co-Authors: Ofer Reizes, Stephen C. Benoit, Deborah J CleggAbstract:Body weight is tightly regulated by a feedback mechanism involving peripheral adiposity signals and multiple central nervous system neurotransmitter pathways. Despite the tight regulation of body weight there is an increase in the prevalence of obesity and overweight in Western society. Obesity and overweight are conditions of excess body weight stored as fat. Syndecan-3, a member of the Syndecan family of type I transmembrane heparan sulfate proteoglycans is a novel a regulator of feeding behavior and body weight. Syndecans are extracellular matrix molecules (ECMs) that modulate cell adhesion, cell-cell interactions and ligand-receptor interactions. The finding that Syndecan-3 can regulate body weight is novel and provides a unique link between the extracellular matrix and body weight regulatory mechanisms. Uniquely, hormones such as leptin previously thought only to regulate body weight by modulating neuropeptide levels, have now been demonstrated to regulate neuronal plasticity in the hypothalamus. ECMs and Syndecans have long been recognized as regulators of plasticity. Therefore, this review will focus on highlighting the role of Syndecans and in particular Syndecan-3 in neuronal development and synaptic organization and how these processes may integrate body weight regulation. As part of this review, we will highlight how Syndecan-3 can mediate the activity of adiposity signals, such as leptin, and facilitate changes in neuronal plasticity.
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insulin promotes shedding of Syndecan ectodomains from 3t3 l1 adipocytes a proposed mechanism for stabilization of extracellular lipoprotein lipase
Biochemistry, 2006Co-Authors: Ofer Reizes, Merton Bernfield, Olga Goldberger, April C Smith, Perry E BickelAbstract:Syndecans are a family of four transmembrane heparan sulfate proteoglycans that act as coreceptors for a variety of cell-surface ligands and receptors. Receptor activation in several cell types leads to shedding of Syndecan-1 and Syndecan-4 ectodomains into the extracellular space by metalloproteinase-mediated cleavage of the Syndecan core protein. We have found that 3T3-L1 adipocytes express Syndecan-1 and Syndecan-4 and that their ectodomains are shed in response to insulin in a dose-, time-, and metalloproteinase-dependent manner. Insulin responsive shedding is not seen in 3T3-L1 fibroblasts. This shedding involves both Ras-MAP kinase and phosphatidylinositol 3-kinase pathways. In response to insulin, adipocytes are known to secrete active lipoprotein lipase, an enzyme that binds to heparan sulfate on the luminal surface of capillary endothelia. Lipoprotein lipase is transported as a stable enzyme from its site of synthesis to its site of action, but the transport mechanism is unknown. Our studies indicate that shed adipocyte Syndecans associate with lipoprotein lipase. The shed Syndecan ectodomain can stabilize active lipoprotein lipase. These data suggest that Syndecan ectodomains, shed by adipocytes in response to insulin, are physiological extracellular chaperones for lipoprotein lipase as it translocates from its site of synthesis to its site of action.
Jim Middleton - One of the best experts on this subject based on the ideXlab platform.
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Soluble Syndecan-3 binds chemokines, reduces leukocyte migration in vitro and ameliorates disease severity in models of rheumatoid arthritis
Arthritis Research & Therapy, 2019Co-Authors: Andrew D. Eustace, Emily F. Mcnaughton, Sophie King, Oksana Kehoe, Andreas J. Kungl, Derek L. Mattey, Angela H. Nobbs, Neil A. Williams, Jim MiddletonAbstract:Syndecans are heparan sulfate proteoglycans that occur in membrane-bound or soluble forms. Syndecan-3, the least well-characterised of the Syndecan family, is highly expressed on synovial endothelial cells in rheumatoid arthritis patients. Here, it binds pro-inflammatory chemokines with evidence for a role in chemokine presentation and leukocyte trafficking into the joint, promoting the inflammatory response. In this study, we explored the role of soluble Syndecan-3 as a binder of chemokines and as an anti-inflammatory and therapeutic molecule. A human monocytic cell line and CD14+ PBMCs were utilised in both Boyden chamber and trans-endothelial migration assays. Soluble Syndecan-3 was tested in antigen-induced and collagen-induced in vivo arthritis models in mice. ELISA and isothermal fluorescence titration assays assessed the binding affinities. Syndecan-3 expression was identified by flow cytometry and PCR, and levels of shedding by ELISA. Using in vitro and in vivo models, soluble Syndecan-3 inhibited leukocyte migration in vitro in response to CCL7 and its administration in murine models of rheumatoid arthritis reduced histological disease severity. Using isothermal fluorescence titration, the binding affinity of soluble Syndecan-3 to inflammatory chemokines CCL2, CCL7 and CXCL8 was determined, revealing little difference, with Kds in the low nM range. TNFα increased cell surface expression and shedding of Syndecan-3 from cultured human endothelial cells. Furthermore, soluble Syndecan-3 occurred naturally in the sera of patients with rheumatoid arthritis and periodontitis, and its levels correlated with Syndecan-1. This study shows that the addition of soluble Syndecan-3 may represent an alternative therapeutic approach in inflammatory disease.
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Syndecan 3 is selectively pro inflammatory in the joint and contributes to antigen induced arthritis in mice
Arthritis Research & Therapy, 2014Co-Authors: Oksana Kehoe, Jim Middleton, Ofer Reizes, Andrew D. Eustace, Sophie King, Neena Kalia, Charlotte Boyes, Anwen Sian Williams, Angela Margaret PattersonAbstract:Syndecans are heparan sulphate proteoglycans expressed by endothelial cells. Syndecan-3 is expressed by synovial endothelial cells of rheumatoid arthritis (RA) patients where it binds chemokines, suggesting a role in leukocyte trafficking. The objective of the current study was to examine the function of Syndecan-3 in joint inflammation by genetic deletion in mice and compare with other tissues. Chemokine C-X-C ligand 1 (CXCL1) was injected in the joints of Syndecan-3−/−and wild-type mice and antigen-induced arthritis performed. For comparison chemokine was administered in the skin and cremaster muscle. Intravital microscopy was performed in the cremaster muscle. Administration of CXCL1 in knee joints of Syndecan-3−/−mice resulted in reduced neutrophil accumulation compared to wild type. This was associated with diminished presence of CXCL1 at the luminal surface of synovial endothelial cells where this chemokine clustered and bound to heparan sulphate. Furthermore, in the arthritis model Syndecan-3 deletion led to reduced joint swelling, leukocyte accumulation, cartilage degradation and overall disease severity. Conversely, CXCL1 administration in the skin of Syndecan-3 null mice provoked increased neutrophil recruitment and was associated with elevated luminal expression of E-selectin by dermal endothelial cells. Similarly in the cremaster, intravital microscopy showed increased numbers of leukocytes adhering and rolling in venules in Syndecan-3−/−mice in response to CXCL1 or tumour necrosis factor alpha. This study shows a novel role for Syndecan-3 in inflammation. In the joint it is selectively pro-inflammatory, functioning in endothelial chemokine presentation and leukocyte recruitment and cartilage damage in an RA model. Conversely, in skin and cremaster it is anti-inflammatory.
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Syndecan-3 is selectively pro-inflammatory in the joint and contributes to antigen-induced arthritis in mice
Arthritis Research & Therapy, 2014Co-Authors: Oksana Kehoe, Ofer Reizes, Andrew D. Eustace, Sophie King, Neena Kalia, Charlotte Boyes, Anwen Sian Williams, Angela Margaret Patterson, Jim MiddletonAbstract:Introduction Syndecans are heparan sulphate proteoglycans expressed by endothelial cells. Syndecan-3 is expressed by synovial endothelial cells of rheumatoid arthritis (RA) patients where it binds chemokines, suggesting a role in leukocyte trafficking. The objective of the current study was to examine the function of Syndecan-3 in joint inflammation by genetic deletion in mice and compare with other tissues.