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Gorsi B, Liu F, Ma X, Chico TJA, v A, Kramer KL, Bridges E, Monteiro R, Harris AL, Patient R, Stringer SE. The heparan sulfate editing enzyme Sulf1 plays a novel role in zebrafish VegfA mediated arterial venous identity. Angiogenesis 2014; 17:77-91. [PMID: 23959107 DOI: 10.1007/s10456-013-9379-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 08/05/2013] [Indexed: 11/26/2022]
Abstract
Arterial and venous specification is critical for establishing and maintaining a functioning vascular system, and defects in key arteriovenous signaling pathways including VEGF (vascular endothelial growth factor) lead to congenital arteriopathies. The activities of VEGF, are in part controlled by heparan sulfate (HS) proteoglycans, significant components of the endothelial glycocalyx. The level of 6-O sulfation on HS polysaccharide chains, that mediate the interaction between HS and VEGFA, is edited at the cell surface by the enzyme SULF1. We investigated the role of sulf1 in vascular development. In zebrafish sulf1 is expressed in the head and tail vasculature, corresponding spatially and temporally with vascular development. Targeted knockdown of sulf1 by antisense morpholinos resulted in severe vascular patterning and maturation defects. 93 % of sulf1 morphants show dysmorphogenesis in arterial development leading to occlusion of the distal aorta and lack of axial and cranial circulation. Co-injection of vegfa165 mRNA rescued circulatory defects. While the genes affecting haematopoiesis are unchanged, expression of several arterial markers downstream of VegfA signalling such as notch and ephrinB2 are severely reduced in the dorsal aorta, with a concomitant increase in expression of the venous markers flt4 in the dorsal aorta of the morphants. Furthermore, in vitro, lack of SULF1 expression downregulates VEGFA-mediated arterial marker expression, confirming that Sulf1 mediates arterial specification by regulating VegfA165 activity. This study provides the first in vivo evidence for the integral role of the endothelial glycocalyx in specifying arterial-venous identity, vascular patterning and arterial integrity, and will help to better understand congenital arteriopathies.
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van Wijk XM, Thijssen VL, Lawrence R, van den Broek SA, Dona M, Naidu N, Oosterhof A, van de Westerlo EM, Kusters LJ, Khaled Y, Jokela TA, Nowak-Sliwinska P, Kremer H, Stringer SE, Griffioen AW, van Wijk E, van Delft FL, van Kuppevelt TH. Interfering with UDP-GlcNAc metabolism and heparan sulfate expression using a sugar analogue reduces angiogenesis. ACS Chem Biol 2013; 8:2331-8. [PMID: 23972127 DOI: 10.1021/cb4004332] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Heparan sulfate (HS), a long linear polysaccharide, is implicated in various steps of tumorigenesis, including angiogenesis. We successfully interfered with HS biosynthesis using a peracetylated 4-deoxy analogue of the HS constituent GlcNAc and studied the compound's metabolic fate and its effect on angiogenesis. The 4-deoxy analogue was activated intracellularly into UDP-4-deoxy-GlcNAc, and HS expression was inhibited up to ∼96% (IC50 = 16 μM). HS chain size was reduced, without detectable incorporation of the 4-deoxy analogue, likely due to reduced levels of UDP-GlcNAc and/or inhibition of glycosyltransferase activity. Comprehensive gene expression analysis revealed reduced expression of genes regulated by HS binding growth factors such as FGF-2 and VEGF. Cellular binding and signaling of these angiogenic factors was inhibited. Microinjection in zebrafish embryos strongly reduced HS biosynthesis, and angiogenesis was inhibited in both zebrafish and chicken model systems. All of these data identify 4-deoxy-GlcNAc as a potent inhibitor of HS synthesis, which hampers pro-angiogenic signaling and neo-vessel formation.
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Affiliation(s)
| | - Victor L. Thijssen
- Angiogenesis
Laboratory, Department of Medical Oncology, VU University Medical Centre, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | | - Tiina A. Jokela
- Institute
of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Patrycja Nowak-Sliwinska
- Angiogenesis
Laboratory, Department of Medical Oncology, VU University Medical Centre, Amsterdam, The Netherlands
- Institute
of Bio-Engineering, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | | | - Sally E. Stringer
- Cardiovascular
Research Group, University of Manchester, Manchester, United Kingdom
| | - Arjan W. Griffioen
- Angiogenesis
Laboratory, Department of Medical Oncology, VU University Medical Centre, Amsterdam, The Netherlands
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Egom EE, Mamas MA, Chacko S, Stringer SE, Charlton-Menys V, El-Omar M, Chirico D, Clarke B, Neyses L, Cruickshank JK, Lei M, Fath-Ordoubadi F. Serum sphingolipids level as a novel potential marker for early detection of human myocardial ischaemic injury. Front Physiol 2013; 4:130. [PMID: 23781203 PMCID: PMC3680707 DOI: 10.3389/fphys.2013.00130] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/17/2013] [Indexed: 11/13/2022] Open
Abstract
Background: Ventricular tachyarrhythmias are the most common and often the first manifestation of coronary heart disease and lead to sudden cardiac death (SCD). Early detection/identification of acute myocardial ischaemic injury at risk for malignant ventricular arrhythmias in patients remains an unmet medical need. In the present study, we examined the sphingolipids level after transient cardiac ischaemia following temporary coronary artery occlusion during percutaneous coronary intervention (PCI) in patients and determined the role of sphingolipids level as a novel marker for early detection of human myocardial ischaemic injury. Methods and Results: Venous samples were collected from either the coronary sinus (n = 7) or femoral vein (n = 24) from 31 patients aged 40–73 years-old at 1, 5 min, and 12 h, following elective PCI. Plasma sphingolipids levels were assessed by HPLC. At 1 min coronary sinus levels of sphingosine 1-phosphate (S1P), sphingosine (SPH), and sphinganine (SA) were increased by 314, 115, and 614%, respectively (n = 7), while peripheral blood levels increased by 79, 68, and 272% (n = 24). By 5 min, coronary sinus S1P and SPH levels increased further (720%, 117%), as did peripheral levels of S1P alone (792%). Where troponin T was detectable at 12 h (10 of 31), a strong correlation was found with peak S1P (R2 = 0.818; P < 0.0001). Conclusion: For the first time, we demonstrate the behavior of plasma sphingolipids following transient cardiac ischaemia in humans. The observation supports the important role of sphingolipids level as a potential novel marker of transient or prolonged myocardial ischaemia.
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Affiliation(s)
- Emmanuel E Egom
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University Halifax, NS, Canada ; Faculty of Medicine and Human Sciences, Institute of Cardiovascular Sciences, University of Manchester Manchester, UK
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Williamson KA, Hamilton A, Reynolds JA, Sipos P, Crocker I, Stringer SE, Alexander YM. Age-related impairment of endothelial progenitor cell migration correlates with structural alterations of heparan sulfate proteoglycans. Aging Cell 2013. [PMID: 23190312 DOI: 10.1111/acel.12031] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aging poses one of the largest risk factors for the development of cardiovascular disease. The increased propensity toward vascular pathology with advancing age maybe explained, in part, by a reduction in the ability of circulating endothelial progenitor cells to contribute to vascular repair and regeneration. Although there is evidence to suggest that colony forming unit-Hill cells and circulating angiogenic cells are subject to age-associated changes that impair their function, the impact of aging on human outgrowth endothelial cell (OEC) function has been less studied. We demonstrate that OECs isolated from cord blood or peripheral blood samples from young and old individuals exhibit different characteristics in terms of their migratory capacity. In addition, age-related structural changes were discovered in OEC heparan sulfate (HS), a glycocalyx component that is essential in many signalling pathways. An age-associated decline in the migratory response of OECs toward a gradient of VEGF significantly correlated with a reduction in the relative percentage of the trisulfated disaccharide, 2-O-sulfated-uronic acid, N, 6-O-sulfated-glucosamine (UA[2S]-GlcNS[6S]), within OEC cell surface HS polysaccharide chains. Furthermore, disruption of cell surface HS reduced the migratory response of peripheral blood-derived OECs isolated from young subjects to levels similar to that observed for OECs from older individuals. Together these findings suggest that aging is associated with alterations in the fine structure of HS on the cell surface of OECs. Such changes may modulate the migration, homing, and engraftment capacity of these repair cells, thereby contributing to the progression of endothelial dysfunction and age-related vascular pathologies.
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Affiliation(s)
- Kate A. Williamson
- Cardiovascular Research Group; University of Manchester; 3rd Floor Core Technology Facility, 46 Grafton St.; Manchester; M13 9NT; UK
| | - Andrew Hamilton
- Cardiovascular Research Group; University of Manchester; 3rd Floor Core Technology Facility, 46 Grafton St.; Manchester; M13 9NT; UK
| | | | - Peter Sipos
- Maternal and Fetal Health Research Centre; University of Manchester; Manchester; UK
| | - Ian Crocker
- Maternal and Fetal Health Research Centre; University of Manchester; Manchester; UK
| | - Sally E. Stringer
- Cardiovascular Research Group; University of Manchester; 3rd Floor Core Technology Facility, 46 Grafton St.; Manchester; M13 9NT; UK
| | - Yvonne M. Alexander
- Cardiovascular Research Group; University of Manchester; 3rd Floor Core Technology Facility, 46 Grafton St.; Manchester; M13 9NT; UK
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Abstract
Age is a significant risk factor for the development of vascular diseases, such as atherosclerosis. Although pharmacological treatments, including statins and anti-hypertensive drugs, have improved the prognosis for patients with cardiovascular disease, it remains a leading cause of mortality in those aged 65 years and over. Furthermore, given the increased life expectancy of the population in developed countries, there is a clear need for alternative treatment strategies. Consequently, the relationship between aging and progenitor cell-mediated repair is of great interest. Endothelial progenitor cells (EPCs) play an integral role in the cellular repair mechanisms for endothelial regeneration and maintenance. However, EPCs are subject to age-associated changes that diminish their number in circulation and function, thereby enhancing vascular disease risk. A great deal of research is aimed at developing strategies to harness the regenerative capacity of these cells. In this review, we discuss the current understanding of the cells termed “EPCs,” examine the impact of age on EPC-mediated repair and identify therapeutic targets with potential for attenuating the age-related decline in vascular health via beneficial actions on EPCs.
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Affiliation(s)
- K Williamson
- Cardiovascular Research Group, School of Biomedicine, University of Manchester Manchester, UK
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Egom EEA, Mohamed TMA, Mamas MA, Shi Y, Liu W, Chirico D, Stringer SE, Ke Y, Shaheen M, Wang T, Chacko S, Wang X, Solaro RJ, Fath-Ordoubadi F, Cartwright EJ, Lei M. Activation of Pak1/Akt/eNOS signaling following sphingosine-1-phosphate release as part of a mechanism protecting cardiomyocytes against ischemic cell injury. Am J Physiol Heart Circ Physiol 2011; 301:H1487-95. [PMID: 21705677 PMCID: PMC3197364 DOI: 10.1152/ajpheart.01003.2010] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We investigated whether plasma long-chain sphingoid base (LCSB) concentrations are altered by transient cardiac ischemia during percutaneous coronary intervention (PCI) in humans and examined the signaling through the sphingosine-1-phosphate (S1P) cascade as a mechanism underlying the S1P cardioprotective effect in cardiac myocytes. Venous samples were collected from either the coronary sinus (n = 7) or femoral vein (n = 24) of 31 patients at 1 and 5 min and 12 h, following induction of transient myocardial ischemia during elective PCI. Coronary sinus levels of LCSB were increased by 1,072% at 1 min and 941% at 5 min (n = 7), while peripheral blood levels of LCSB were increased by 579% at 1 min, 617% at 5 min, and 436% at 12 h (n = 24). In cultured cardiac myocytes, S1P, sphingosine (SPH), and FTY720, a sphingolipid drug candidate, showed protective effects against CoCl induced hypoxia/ischemic cell injury by reducing lactate dehydrogenase activity. Twenty-five nanomolars of FTY720 significantly increased phospho-Pak1 and phospho-Akt levels by 56 and 65.6% in cells treated with this drug for 15 min. Further experiments demonstrated that FTY720 triggered nitric oxide release from cardiac myocytes is through pertussis toxin-sensitive phosphatidylinositol 3-kinase/Akt/endothelial nitric oxide synthase signaling. In ex vivo hearts, ischemic preconditioning was cardioprotective in wild-type control mice (Pak1f/f), but this protection appeared to be ineffective in cardiomyocyte-specific Pak1 knockout (Pak1cko) hearts. The present study provides the first direct evidence of the behavior of plasma sphingolipids following transient cardiac ischemia with dramatic and early increases in LCSB in humans. We also demonstrated that S1P, SPH, and FTY720 have protective effects against hypoxic/ischemic cell injury, likely a Pak1/Akt1 signaling cascade and nitric oxide release. Further study on a mouse model of cardiac specific deletion of Pak1 demonstrates a crucial role of Pak1 in cardiac protection against ischemia/reperfusion injury.
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Gorsi B, Whelan S, Stringer SE. Dynamic expression patterns of 6-O endosulfatases during zebrafish development suggest a subfunctionalisation event for sulf2. Dev Dyn 2011; 239:3312-23. [PMID: 20981828 DOI: 10.1002/dvdy.22456] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The 6-O-endosulfatase enzymes (Sulfs) edit the final sulfation pattern and function of heparan sulfate (HS) by removal of 6-O-sulfate groups from the chain. To date, two mammalian sulf genes have been identified that regulate many signalling pathways during embryonic development. In zebrafish a sulf1 ortholog and duplicate copies of the mammalian sulf2 gene, sulf2a and sulf2, have been identified, which contain conserved motifs characteristic of vertebrate sulf genes. Zebrafish sulf1 and sulf2a are broadly expressed in the central nervous system (CNS) and non-neuronal tissue including heart, somite boundaries, olfactory system, and otic vesicle, whereas sulf2 expression is almost entirely restricted to the CNS. The duplicate copies of sulf2 have distinct expression patterns, which together mirror that of mouse sulf2, suggesting duplication in the teleost lineage has been followed by subfunctionalisation, whereby both genes need to be preserved by selection to ensure the ancestral gene's expression profile and function is maintained.
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Affiliation(s)
- Bushra Gorsi
- Cardiovascular Medicine, Faculty of Medical and Human Sciences, University of Manchester, Manchester, United Kingdom
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8
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Yan J, Stringer SE, Hamilton A, Charlton-Menys V, Götting C, Müller B, Aeschlimann D, Alexander MY. Decorin GAG synthesis and TGF-β signaling mediate Ox-LDL-induced mineralization of human vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 2011; 31:608-15. [PMID: 21205989 DOI: 10.1161/atvbaha.110.220749] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Decorin and oxidized low-density lipoprotein (Ox-LDL) independently induce osteogenic differentiation of vascular smooth muscle cells (VSMCs). We aimed to determine whether decorin glycosaminoglycan (GAG) chain synthesis contributes to Ox-LDL-induced differentiation and calcification of human VSMCs in vitro. METHODS AND RESULTS Human VSMCs treated with Ox-LDL to induce oxidative stress showed increased alkaline phosphatase (ALP) activity, accelerated mineralization, and a difference in both decorin GAG chain biosynthesis and CS/DS structure compared with untreated controls. Ox-LDL increased mRNA abundance of both xylosyltransferase (XT)-I, the key enzyme responsible for GAG chain biosynthesis and Msx2, a marker of osteogenic differentiation. Furthermore, downregulation of XT-I expression using small interfering RNA blocked Ox-LDL-induced VSMC mineralization. Adenoviral-mediated overexpression of decorin, but not a mutated unglycanated form, accelerated mineralization of VSMCs, suggesting GAG chain addition on decorin is crucial for the process of differentiation. The decorin-induced VSMC osteogenic differentiation involved activation of the transforming growth factor (TGF)-β pathway, because it was attenuated by blocking of TGF-β receptor signaling and because decorin overexpression potentiated phosphorylation of the downstream signaling molecule smad2. CONCLUSIONS These studies provide direct evidence that oxidative stress-mediated decorin GAG chain synthesis triggers TGF-β signaling and mineralization of VSMCs in vitro.
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Affiliation(s)
- Jianyun Yan
- Cardiovascular Research Group, University of Manchester, United Kingdom
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9
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Reijnders CMA, Waaijer CJF, Hamilton A, Buddingh EP, Dijkstra SPD, Ham J, Bakker E, Szuhai K, Karperien M, Hogendoorn PCW, Stringer SE, Bovée JVMG. No haploinsufficiency but loss of heterozygosity for EXT in multiple osteochondromas. Am J Pathol 2010; 177:1946-57. [PMID: 20813973 DOI: 10.2353/ajpath.2010.100296] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Multiple osteochondromas (MO) is an autosomal dominant disorder caused by germline mutations in EXT1 and/or EXT2. In contrast, solitary osteochondroma (SO) is nonhereditary. Products of the EXT gene are involved in heparan sulfate (HS) biosynthesis. In this study, we investigated whether osteochondromas arise via either loss of heterozygosity (2 hits) or haploinsufficiency. An in vitro three-dimensional chondrogenic pellet model was used to compare heterozygous bone marrow-derived mesenchymal stem cells (MSCs EXT(wt/-)) of MO patients with normal MSCs and the corresponding tumor specimens (presumed EXT(-/-)). We demonstrated a second hit in EXT in five of eight osteochondromas. HS chain length and structure, in vitro chondrogenesis, and EXT expression levels were identical in both EXT(wt/-) and normal MSCs. Immunohistochemistry for HS, HS proteoglycans, and HS-dependent signaling pathways (eg, TGF-β/BMP, Wnt, and PTHLH) also showed no differences. The cartilaginous cap of osteochondroma contained a mixture of HS-positive and HS-negative cells. Because a heterozygous EXT mutation does not affect chondrogenesis, EXT, HS, or downstream signaling pathways in MSCs, our results refute the haploinsufficiency theory. We found a second hit in 63% of analyzed osteochondromas, supporting the hypothesis that osteochondromas arise via loss of heterozygosity. The detection of the second hit may depend on the ratio of HS-positive (normal) versus HS-negative (mutated) cells in the cartilaginous cap of the osteochondroma.
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10
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Gorsi B, Stringer SE. Tinkering with heparan sulfate sulfation to steer development. Trends Cell Biol 2007; 17:173-7. [PMID: 17320398 DOI: 10.1016/j.tcb.2007.02.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Revised: 01/09/2007] [Accepted: 02/08/2007] [Indexed: 12/22/2022]
Abstract
Heparan sulfate (HS) proteoglycans, at the cell surface and extracellular matrix, facilitate ligand-receptor interactions crucial to many physiological processes. The distinct sulfation patterns of HS sugar chains presented by their protein core are key to HS proteoglycan activity. Tight regulation of several Golgi complex enzyme families is crucial to produce complex tissue-specific HS sequences. Several in vivo models deficient in HS biosynthesis enzymes demonstrate that developmental abnormalities result from modified HS structure. This review will discuss the plasticity of sulfation requirements on HS for activating protein ligands, which might reflect a flexible HS biosynthetic mechanism. In addition, the latest discovery of HS acting enzymes, the Sulfs, responsible for extracellular tweaking of HS sulfation levels subsequent to biosynthesis will be considered.
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Affiliation(s)
- Bushra Gorsi
- Division of Cardiac and Endocrine Sciences, University of Manchester, UK, M13 9NT
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11
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Abstract
The presence of HS (heparan sulphate) proteoglycans on the cell surface and in the extracellular environment is critical to many physiological processes including the growth of new blood vessels from pre-existing vasculature (angiogenesis). A plethora of growth factors and their receptors, extracellular matrix molecules and enzymes bind to specific sites on the HS sugar chain. For example, HS proteoglycans have profound effects on the bioactivity of the key angiogenic factor VEGF (vascular endothelial growth factor) (VEGF165), affecting its diffusion, half-life and interaction with its tyrosine kinase receptors. A number of HS structural features that mediate the specific binding of VEGF165, including sulphation requirements, have been determined. In parallel, zebrafish embryos were used as a vertebrate model system to study the role in vascular development of the biosynthetic enzymes that create these specific binding sites on HS. It was discovered that knockdown of one of the HS 6-O-sulphotransferases in zebrafish with morpholino antisense oligonucleotides reduced vascular branching and corresponded to changes in the HS structure. The roles of the extracellular 6-O-sulphatase enzymes, the sulfs, in vascular development are now being investigated. Both oligosaccharides and small molecule biosynthetic enzyme inhibitors could be valuable HS-based strategies for controlling aberrant angiogenesis in diseases as diverse as cancer and heart disease.
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Affiliation(s)
- S E Stringer
- Division of Cardiovascular and Endocrine Sciences, School of Medicine, University of Manchester, Core Technologies Facility, UK.
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12
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Robinson CJ, Mulloy B, Gallagher JT, Stringer SE. VEGF165-binding sites within heparan sulfate encompass two highly sulfated domains and can be liberated by K5 lyase. J Biol Chem 2005; 281:1731-40. [PMID: 16258170 DOI: 10.1074/jbc.m510760200] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The vascular endothelial growth factor (VEGF) family of proteins controls the formation and growth of blood vessels. The most potent and widely expressed isoform, VEGF165, is secreted as a disulfide-linked homodimer with two identical heparin-binding sites. Interactions with heparan sulfate (HS) regulate the diffusion, half-life, and affinity of VEGF165 for its signaling receptors. We have determined a number of key HS structural features that mediate the specific binding of the VEGF165 dimer. Carboxylate groups and 2-O-, 6-O-, and N-sulfation of HS contributed to the strength of the VEGF165 interaction; however, 6-O-sulfates appeared to be particularly important. Cleavage of HS by heparinase, heparitinase, or heparanase severely reduced VEGF165 binding. In contrast, K5 lyase-cleaved HS retained significant VEGF165 affinity, suggesting that binding sites for the growth factor are present within extended stretches of sulfation. Binding studies and molecular modeling demonstrated that an oligosaccharide 6 or 7 residues long was sufficient to fully occupy the heparin-binding site of a VEGF165 monomer. The data presented are consistent with a model whereby the two heparin-binding sites of the VEGF165 dimer interact simultaneously with highly sulfated S-domain regions of the HS chain that can be linked through a stretch of transition sequence.
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Affiliation(s)
- Christopher J Robinson
- Cancer Research UK and University of Manchester Department of Medical Oncology, Christie Hospital National Health Service Trust, Wilmslow Road, Manchester M20 4BX, United Kindgom.
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Chen E, Stringer SE, Rusch MA, Selleck SB, Ekker SC. A unique role for 6-O sulfation modification in zebrafish vascular development. Dev Biol 2005; 284:364-76. [PMID: 16009360 DOI: 10.1016/j.ydbio.2005.05.032] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 05/22/2005] [Accepted: 05/25/2005] [Indexed: 10/25/2022]
Abstract
Heparan sulfate proteoglycans are important modulators of growth factor signaling in a variety of patterning processes. Secreted growth factors that play critical roles in angiogenesis bind to heparan sulfate, and this association is affected by 6-O-sulfation of the heparan sulfate chains. Addition of 6-O-sulfate is catalyzed by a family of sulfotransferases (HS6STs), and genetic manipulation of their function permits an assessment of their contribution to vascular assembly. We report on the biochemical activity and expression patterns of two zebrafish HS6ST genes. In situ hybridization reveals dynamic and distinct expression patterns of these two genes during development. Structural analysis of heparan sulfate from wild-type and morpholino antisense 'knockdown' embryos suggests that HS6ST-1 and HS6ST-2 have similar biochemical activity. HS6ST-2, but not HS6ST-1, morphants exhibit abnormalities in the branching morphogenesis of the caudal vein during embryonic development of the zebrafish. Our finding that HS6ST-2 is required for the branching morphogenesis of the caudal vein is the first in vivo evidence for an essential role of a gene encoding a heparan sulfate modifying enzyme in vertebrate angiogenesis. Our analysis of two zebrafish HS6ST genes suggests that a wide range of biological processes may be regulated by an array of sulfation-modifying enzymes in the vertebrate genome.
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Affiliation(s)
- Eleanor Chen
- Arnold and Mabel Beckman Center for Transposon Research, Department of Genetics, Cell Biology and Development, University of Minnesota, 6-160 Jackson Hall, Minneapolis, MN 55455, USA
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14
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Pan C, Nelson MS, Reyes M, Koodie L, Brazil JJ, Stephenson EJ, Zhao RC, Peters C, Selleck SB, Stringer SE, Gupta P. Functional abnormalities of heparan sulfate in mucopolysaccharidosis-I are associated with defective biologic activity of FGF-2 on human multipotent progenitor cells. Blood 2005; 106:1956-64. [PMID: 15947088 PMCID: PMC1895139 DOI: 10.1182/blood-2005-02-0657] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In mucopolysaccharidosis-I (MPS-I), alpha-L-iduronidase deficiency leads to progressive heparan sulfate (HS) and dermatan sulfate (DS) glycosaminoglycan (GAG) accumulation. The functional consequences of these accumulated molecules are unknown. HS critically influences tissue morphogenesis by binding to and modulating the activity of several cytokines (eg, fibroblast growth factors [FGFs]) involved in developmental patterning. We recently isolated a multipotent progenitor cell from postnatal human bone marrow, which differentiates into cells of all 3 embryonic lineages. The availability of multipotent progenitor cells from healthy volunteers and patients with MPS-I (Hurler syndrome) provides a unique opportunity to directly examine the functional effects of abnormal HS on cytokine-mediated stem-cell proliferation and survival. We demonstrate here that abnormally sulfated HS in Hurler multipotent progenitor cells perturb critical FGF-2-FGFR1-HS interactions, resulting in defective FGF-2-induced proliferation and survival of Hurler multipotent progenitor cells. Both the mitogenic and survival-promoting activities of FGF-2 were restored by substitution of Hurler HS by normal HS. This perturbation of critical HS-cytokine receptor interactions may represent a mechanism by which accumulated HS contributes to the developmental pathophysiology of Hurler syndrome. Similar mechanisms may operate in the pathogenesis of other diseases where structurally abnormal GAGs accumulate.
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Affiliation(s)
- Chendong Pan
- Associate Professor of Medicine, University of Minnesota Medical School, Hematology/Oncology Section (111E), VA Medical Center, One Veterans Dr, Minneapolis, MN 55417.
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15
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Lee JS, von der Hardt S, Rusch MA, Stringer SE, Stickney HL, Talbot WS, Geisler R, Nüsslein-Volhard C, Selleck SB, Chien CB, Roehl H. Axon Sorting in the Optic Tract Requires HSPG Synthesis by ext2 (dackel) and extl3 (boxer). Neuron 2004; 44:947-60. [PMID: 15603738 DOI: 10.1016/j.neuron.2004.11.029] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Revised: 09/15/2004] [Accepted: 11/01/2004] [Indexed: 10/26/2022]
Abstract
Retinal ganglion cell (RGC) axons are topographically ordered in the optic tract according to their retinal origin. In zebrafish dackel (dak) and boxer (box) mutants, some dorsal RGC axons missort in the optic tract but innervate the tectum topographically. Molecular cloning reveals that dak and box encode ext2 and extl3, glycosyltransferases implicated in heparan sulfate (HS) biosynthesis. Both genes are required for HS synthesis, as shown by biochemical and immunohistochemical analysis, and are expressed maternally and then ubiquitously, likely playing permissive roles. Missorting in box can be rescued by overexpression of extl3. dak;box double mutants show synthetic pathfinding phenotypes that phenocopy robo2 mutants, suggesting that Robo2 function requires HS in vivo; however, tract sorting does not require Robo function, since it is normal in robo2 null mutants. This genetic evidence that heparan sulfate proteoglycan function is required for optic tract sorting provides clues to begin understanding the underlying molecular mechanisms.
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Affiliation(s)
- Jeong-Soo Lee
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, Utah 84103, USA
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16
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Abstract
The CXC chemokine platelet factor 4 (PF4) appears to inhibit tumour growth through its modulation of the activity of angiogenic growth factors. We investigated the heparan sulphate-dependent mechanism of PF4 inhibition of fibroblast growth factor 2 (FGF-2). The ability of PF4 to bind simultaneously to both FGF-2 and HS was assessed using affinity gel chromatography. Thirty-three to forty-two percent more HS bound to the FGF-2 affinity gel in the presence of PF4 than with HS alone. Protection assays showed that PF4 and FGF-2 bound to adjacent or overlapping sites together covering a 12 kDa stretch of HS. This study suggests that the three components may form a ternary complex. PF4 released at sites of angiogenesis may bind to angiogenic growth factors attached to endothelial cell surface HS to disrupt or prevent them from interacting with their signalling receptors. Manipulation of this mechanism may prove useful for clinical intervention of angiogenesis.
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17
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Stringer SE, Nelson MS, Gupta P. Identification of an MIP-1alpha -binding heparan sulfate oligosaccharide that supports long-term in vitro maintenance of human LTC-ICs. Blood 2003; 101:2243-5. [PMID: 12406885 DOI: 10.1182/blood-2002-08-2588] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously showed that heparan sulfate (HS) is required for in vitro cytokine + chemokine-mediated maintenance of primitive human hematopoietic progenitors. However, HS preparations are mixtures of polysaccharide chains of varying size, structure, and protein-binding abilities. Therefore, we examined whether the long-term culture-initiating cells (LTC-IC) supportive capability of HS is attributable to an oligosaccharide of defined length and protein-binding ability. Oligosaccharides of a wide range of sizes were prepared, and their capability to support human marrow LTC-IC maintenance in the presence of low-dose cytokines and a single chemokine, macrophage inflammatory protein-1alpha (MIP-1alpha), was examined. LTC-IC supportive capability of HS oligosaccharides correlated directly with size and MIP-1alpha binding ability. A specific MIP-1alpha-binding HS oligosaccharide preparation of M(r) 10 kDa that optimally supported LTC-IC maintenance was identified. This oligosaccharide had the structure required for MIP-1alpha binding, which we have recently described. The present study defines the minimum size and structural features of LTC-IC supportive HS.
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Affiliation(s)
- Sally E Stringer
- Paterson Institute for Cancer Research, Manchester, United Kingdom
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18
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Abstract
Heparin is a highly sulfated glycosaminoglycan widely used as an anticoagulant. Modifications in its relatively uniform structure appear to be key to its recognition and modulation of serine proteases, growth factors, chemokines, and extracellular proteins, as has been most clearly demonstrated in the antithrombin binding site. We sequenced the major oligosaccharides released from mastocytoma heparin by partial nitrous acid using a highly sensitive technique tailored for sequencing of metabolically radiolabeled heparin. It utilizes partial nitrous acid cleavage to allow simultaneous sequencing of the internal components of the oligosaccharide under investigation by specific lysosomal exoenzymes. Sequencing revealed that although the majority of the heparin disaccharides are N-, 2-O-, and 6-O-sulfated, the less sulfated disaccharides (lacking 2-O- or 6-O-sulfates) seem to be spaced out along the chain. The technique may be particularly useful for characterizing heparin from novel sources, such as the glial progenitor cells and Ascidia, as well as for sequencing protein binding sites.
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Affiliation(s)
- Sally E Stringer
- Drug Development Group, Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Manchester M20 4BX, UK.
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19
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Stringer SE, Forster MJ, Mulloy B, Bishop CR, Graham GJ, Gallagher JT. Characterization of the binding site on heparan sulfate for macrophage inflammatory protein 1alpha. Blood 2002; 100:1543-50. [PMID: 12176868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
The CC chemokine macrophage inflammatory protein 1alpha (MIP1alpha) is a key regulator of the proliferation and differentiation of hematopoietic progenitor cells. The activity of MIP1alpha appears to be modulated by its binding to heparan sulfate (HS) proteoglycans, ubiquitous components of the mammalian cell surface and extracellular matrix. In this study we show that HS has highest affinity for the dimeric form of MIP1alpha. The predominantly dimeric BB10010 MIP1alpha interacts with an 8.3-kDa sequence in the HS polysaccharide chain, which it protects from degradation by heparinase enzymes. The major structural motif of this HS fragment appears to consist of 2 sulfate-rich S-domains separated by a short central N-acetylated region. The optimum lengths of these S-domains seem to be 12 to 14 saccharides. We propose that this binding fragment may wrap around the MIP1alpha dimer in a horseshoe shape, facilitating the interaction of the S-domains with the heparin-binding domains on each monomer. Molecular modeling suggests that these S-domains are likely to interact with basic residues Arg 17, Arg 45, and Arg 47 and possibly with Lys 44 on MIP1alpha and that the interconnecting N-acetylated region is of sufficient length to allow the 2 S-domains to bind to these sites on opposite faces of the dimer. Elucidation of the structure of the HS-binding site for MIP1alpha may enable us to devise ways of enhancing its myeloprotective or peripheral blood stem cell mobilization properties, which can be used to improve cancer chemotherapy treatments.
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Affiliation(s)
- Sally E Stringer
- Paterson Institute for Cancer Research, Manchester, United Kingdom.
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20
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Abstract
Vascular endothelial growth factor (VEGF) is a secreted mitogen highly specific for cultured endothelial cells. In vivo VEGF induces microvascular permeability and plays a central role in both angiogenesis and vasculogenesis. VEGF is a promising target for therapeutic intervention in certain pathological conditions that are angiogenesis dependent, most notably the neovascularisation of growing tumours. Through alternative mRNA splicing, a single gene gives rise to several distinct isoforms of VEGF, which differ in their expression patterns as well as their biochemical and biological properties. Two VEGF receptor tyrosine kinases (VEGFRs) have been identified, VEGFR-1 (Flt-1) and VEGFR-2 (KDR/Flk-1). VEGFR-2 seems to mediate almost all observed endothelial cell responses to VEGF, whereas roles for VEGFR-1 are more elusive. VEGFR-1 might act predominantly as a ligand-binding molecule, sequestering VEGF from VEGFR-2 signalling. Several isoform-specific VEGF receptors exist that modulate VEGF activity. Neuropilin-1 acts as a co-receptor for VEGF(165), enhancing its binding to VEGFR-2 and its bioactivity. Heparan sulphate proteoglycans (HSPGs), as well as binding certain VEGF isoforms, interact with both VEGFR-1 and VEGFR-2. HSPGs have a wide variety of functions, such as the ability to partially restore lost function to damaged VEGF(165) and thereby prolonging its biological activity.
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Affiliation(s)
- C J Robinson
- The Cancer Research Campaign Department of Drug Development and the CRC and University of Manchester Department of Medical Oncology, Paterson Institute for Cancer Research, Christie Hospital, Manchester, M20 4BX, UK
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21
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Abstract
The oligodendrocyte-type-2 astrocyte progenitor cells (precursors of oligodendrocytes and type-2 astrocytes) are an excellent system in which to study differentiation as they can be manipulated in vitro. Maintenance of oligodendrocyte-type-2 astrocyte progenitor cells requires basic fibroblast growth factor, a growth factor whose action normally depends on a heparan sulfate coreceptor. Biochemical analysis revealed a most surprising result: that the oligodendrocyte-type-2 astrocyte progenitors did not synthesize heparan sulfate, the near ubiquitous N-sulfated cell surface polysaccharide, but the chemically related heparin in a form that was almost completely N- and O-sulfated. The heparin was detected in the pericellular fraction of the cells and the culture medium. In contrast the differentiated glial subpopulations (oligodendrocytes and type-2 astrocytes) synthesized typical heparan sulfate but with distinctive fine structural features for each cell type. Thus heparin is a unique differentiation marker in the glial lineage. Previously heparin has been found only in a subset of mature mast cells called the connective tissue mast cells. Its presence within the developing nervous system on a precise population of progenitors may confer specific and essential recognition properties on those cells in relation to binding soluble growth and/or differentiation factors and the extracellular matrix.
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Affiliation(s)
- S E Stringer
- Cancer Research Campaign, Paterson Institute of Cancer Research, Christie Hospital, Wilmslow Road, Manchester M20 4BX, United Kingdom.
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22
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Abstract
Platelet factor 4 is a tetrameric heparin binding chemokine released from the alpha-granules of activated platelets. In this study we show that platelet factor 4 binds with high affinity and specificity to an approximately 9-kDa sequence in heparan sulfate, which it protects from degradation by heparinase enzymes. This protected fragment is enriched in N-sulfated disaccharides and iduronate 2-O-sulfate residues, the latter being important for binding to platelet factor 4. The major structural motif of the fragment appears to consist of a pair of sulfated domains positioned at both ends separated by a central mainly N-acetylated region. On the basis of these findings, we propose a model in which the heparan sulfate fragment wraps around the ring of positive charges on platelet factor 4 with the iduronate 2-O-sulfates within the sulfated domains binding strongly to lysine clusters on opposite faces of the tetramer.
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Affiliation(s)
- S E Stringer
- Cancer Research Campaign, Manchester, M20 9BX, United Kingdom
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23
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Abstract
Heparan sulphates, the N-sulphated polysaccharides components of proteoglycans, are common constituents of cell surfaces and the extracellular matrix. The heparan sulphate polysaccharide chain has a unique molecular design in the which the clusters of N- and O-sulphated sugar residues, separated by regions of low sulphation, determine specific protein binding properties. The heparan sulphate chains are attached to various protein cores, which determine the location of the proteoglycan in the cell membrane and extracellular matrix. The diverse functions of heparan sulphate, which range from the control of blood coagulation to the regulation of cell growth and adhesion, depend on the capacity of the chains to activate protein ligands, such as antithrombin III and members of the fibroblast growth factor family. These properties are currently being exploited in the development of synthetic heparan sulphates as anticoagulants and promoters of wound healing. Conversely organic mimics of growth factor activating saccharides could possibly be designed to suppress tumour growth and prevent restenosis after coronary vessel angioplasty.
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Affiliation(s)
- S E Stringer
- Department of Medical Oncology, Paterson Institute for Cancer Research, Christie Hospital, Withington, Manchester, U.K
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