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O'Connell MP, Weeraratna AT. A spoonful of sugar makes the melanoma go: the role of heparan sulfate proteoglycans in melanoma metastasis. Pigment Cell Melanoma Res 2011; 24:1133-47. [PMID: 21978367 DOI: 10.1111/j.1755-148x.2011.00918.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Heparan sulfate proteoglycans (HSPGs) have been shown to regulate signaling in many systems and are of increasing interest in cancer. While these are not the only sugars to drive melanoma metastasis, HSPGs play important roles in driving metastatic signaling cascades in melanoma. The ability of these proteins to modulate ligand-receptor interactions in melanoma has been quite understudied. Recent data from several groups indicate the importance of these ligands in modulating key signaling pathways including Wnt and fibroblast growth factor (FGF) signaling. In this review, we summarize the current knowledge regarding the structure and function of these proteoglycans and their role in melanoma. Understanding how HSPGs modulate signaling in melanoma could lead to new therapeutic approaches via the dampening or heightening of key signaling pathways.
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Affiliation(s)
- M P O'Connell
- Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, PA, USA.
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52
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Topczewski J, Dale RM, Sisson BE. Planar cell polarity signaling in craniofacial development. Organogenesis 2011; 7:255-9. [PMID: 22134372 DOI: 10.4161/org.7.4.18797] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Out of the several signaling pathways controlling craniofacial development, the role of planar cell polarity (PCP) signaling is relatively poorly understood. This pathway, originally identified as a mechanism to maintain cell polarity within the epithelial cells of the Drosophila wing, has been linked to the proper development of a wide variety of tissues in vertebrates and invertebrates. While many of the pathway members are conserved, it appears that some of the members of the pathway act in a tissue-specific manner. Here, we discuss the role of this pathway in vertebrate craniofacial development, highlighting cranial neural crest migration, skull and palate formation and the role of non-traditional modulators of PCP signaling within this developmental process.
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Affiliation(s)
- Jacek Topczewski
- Northwestern University, Feinberg School of Medicine, Department of Pediatrics, Children’s Memorial Research Center, Chicago, IL, USA.
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53
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Freeze HH, Ng BG. Golgi glycosylation and human inherited diseases. Cold Spring Harb Perspect Biol 2011; 3:a005371. [PMID: 21709180 DOI: 10.1101/cshperspect.a005371] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Golgi factory receives custom glycosylates and dispatches its cargo to the correct cellular locations. The process requires importing donor substrates, moving the cargo, and recycling machinery. Correctly glycosylated cargo reflects the Golgi's quality and efficiency. Genetic disorders in the specific equipment (enzymes), donors (nucleotide sugar transporters), or equipment recycling/reorganization components (COG, SEC, golgins) can all affect glycosylation. Dozens of human glycosylation disorders fit these categories. Many other genes, with or without familiar names, well-annotated pedigrees, or likely homologies will join the ranks of glycosylation disorders. Their broad and unpredictable case-by-case phenotypes cross the traditional medical specialty boundaries. The gene functions in patients may be elusive, but their common feature may include altered glycosylation that provide clues to Golgi function. This article focuses on a group of human disorders that affect protein or lipid glycosylation. Readers may find it useful to generalize some of these patient-based, translational observations to their own research.
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Affiliation(s)
- Hudson H Freeze
- Genetic Disease Program, Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA.
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54
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Eames BF, Yan YL, Swartz ME, Levic DS, Knapik EW, Postlethwait JH, Kimmel CB. Mutations in fam20b and xylt1 reveal that cartilage matrix controls timing of endochondral ossification by inhibiting chondrocyte maturation. PLoS Genet 2011; 7:e1002246. [PMID: 21901110 PMCID: PMC3161922 DOI: 10.1371/journal.pgen.1002246] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Accepted: 07/01/2011] [Indexed: 11/18/2022] Open
Abstract
Differentiating cells interact with their extracellular environment over time. Chondrocytes embed themselves in a proteoglycan (PG)-rich matrix, then undergo a developmental transition, termed "maturation," when they express ihh to induce bone in the overlying tissue, the perichondrium. Here, we ask whether PGs regulate interactions between chondrocytes and perichondrium, using zebrafish mutants to reveal that cartilage PGs inhibit chondrocyte maturation, which ultimately dictates the timing of perichondral bone development. In a mutagenesis screen, we isolated a class of mutants with decreased cartilage matrix and increased perichondral bone. Positional cloning identified lesions in two genes, fam20b and xylosyltransferase1 (xylt1), both of which encode PG synthesis enzymes. Mutants failed to produce wild-type levels of chondroitin sulfate PGs, which are normally abundant in cartilage matrix, and initiated perichondral bone formation earlier than their wild-type siblings. Primary chondrocyte defects might induce the bone phenotype secondarily, because mutant chondrocytes precociously initiated maturation, showing increased and early expression of such markers as runx2b, collagen type 10a1, and ihh co-orthologs, and ihha mutation suppressed early perichondral bone in PG mutants. Ultrastructural analyses demonstrated aberrant matrix organization and also early cellular features of chondrocyte hypertrophy in mutants. Refining previous in vitro reports, which demonstrated that fam20b and xylt1 were involved in PG synthesis, our in vivo analyses reveal that these genes function in cartilage matrix production and ultimately regulate the timing of skeletal development.
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Affiliation(s)
- B Frank Eames
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America.
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Secondary peripheral chondrosarcoma evolving from osteochondroma as a result of outgrowth of cells with functional EXT. Oncogene 2011; 31:1095-104. [PMID: 21804604 DOI: 10.1038/onc.2011.311] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Secondary peripheral chondrosarcoma is the result of malignant transformation of a pre-existing osteochondroma, the most common benign bone tumor. Osteochondromas are caused by genetic abnormalities in EXT1 or EXT2: homozygous deletion of EXT1 characterizes sporadic osteochondromas (non-familial/solitary), and germline mutations in EXT1 or EXT2 combined with loss of heterozygosity define hereditary multiple osteochondromas. While cells with homozygous inactivation of EXT and wild-type cells shape osteochondromas, the cellular composition of secondary peripheral chondrosarcomas and the role of EXT in their formation have remained unclear. We report using a targeted-tiling-resolution oligo-array-CGH (array comparative genomic hybridization) that homozygous deletions of EXT1 or EXT2 are much less frequently detected (2/17, 12%) in sporadic secondary peripheral chondrosarcomas than expected based on the assumption that they originate in sporadic osteochondromas, in which homozygous inactivation of EXT1 is found in ~80% of our cases. FISH with an EXT1 probe confirmed that, unlike sporadic osteochondromas, cells from sporadic secondary peripheral chondrosarcomas predominantly retained one (hemizygous deleted loci) or both copies (wild-type) of the EXT1 locus. By immunohistochemistry, we confirm the presence of cells with dysfunctional EXT1 in sporadic osteochondromas and show cells with functional EXT1 in sporadic secondary peripheral chondrosarcomas. These immuno results were verified in osteochondromas and secondary peripheral chondrosarcomas in the setting of hereditary multiple osteochondromas. Our data therefore point to a model of oncogenesis in which the osteochondroma creates a niche in which wild-type cells with functional EXT are predisposed to acquire other mutations giving rise to secondary peripheral chondrosarcoma, indicating that EXT-independent mechanisms are involved in the pathogenesis of secondary peripheral chondrosarcoma.
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56
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Zak BM, Schuksz M, Koyama E, Mundy C, Wells DE, Yamaguchi Y, Pacifici M, Esko JD. Compound heterozygous loss of Ext1 and Ext2 is sufficient for formation of multiple exostoses in mouse ribs and long bones. Bone 2011; 48:979-87. [PMID: 21310272 PMCID: PMC3335264 DOI: 10.1016/j.bone.2011.02.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 01/29/2011] [Accepted: 02/01/2011] [Indexed: 12/27/2022]
Abstract
Multiple Hereditary Exostoses (MHE) syndrome is caused by haploinsufficiency in Golgi-associated heparan sulfate polymerases EXT1 or EXT2 and is characterized by formation of exostoses next to growing long bones and other skeletal elements. Recent mouse studies have indicated that formation of stereotypic exostoses requires a complete loss of Ext expression, suggesting that a similar local loss of EXT function may underlie exostosis formation in patients. To further test this possibility and gain greater insights into pathogenic mechanisms, we created heterozygous Ext1(+/-) and compound Ext1(+/-)/Ext2(+/-) mice. Like Ext2(+/-) mice described previously (Stickens et al. Development 132:5055), Ext1(+/-) mice displayed rib-associated exostosis-like outgrowths only. However, compound heterozygous mice had nearly twice as many outgrowths and, more importantly, displayed stereotypic growth plate-like exostoses along their long bones. Ext1(+/-)Ext2(+/-) exostoses contained very low levels of immuno-detectable heparan sulfate, and Ext1(+/-)Ext2(+/-) chondrocytes, endothelial cells and fibroblasts in vitro produced shortened heparan sulfate chains compared to controls and responded less vigorously to exogenous factors such as FGF-18. We also found that rib outgrowths formed in Ext1(f/+)Col2Cre and Ext1(f/+)Dermo1Cre mice, suggesting that ectopic skeletal tissue can be induced by conditional Ext ablation in local chondrogenic and/or perichondrial cells. The study indicates that formation of stereotypic exostoses requires a significant, but not complete, loss of Ext expression and that exostosis incidence and phenotype are intimately sensitive to, and inversely related to, Ext expression. The data also indicate that the nature and organization of ectopic tissue may be influenced by site-specific anatomical cues and mechanisms.
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Affiliation(s)
- Beverly M Zak
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA.
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57
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de Andrea CE, Prins FA, Wiweger MI, Hogendoorn PCW. Growth plate regulation and osteochondroma formation: insights from tracing proteoglycans in zebrafish models and human cartilage. J Pathol 2011; 224:160-8. [PMID: 21506131 DOI: 10.1002/path.2886] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 02/01/2011] [Accepted: 02/26/2011] [Indexed: 12/18/2022]
Abstract
Proteoglycans are secreted into the extracellular matrix of virtually all cell types and function in several cellular processes. They consist of a core protein onto which glycosaminoglycans (e.g., heparan or chondroitin sulphates), are attached. Proteoglycans are important modulators of gradient formation and signal transduction. Impaired biosynthesis of heparan sulphate glycosaminoglycans causes osteochondroma, the most common bone tumour to occur during adolescence. Cytochemical staining with positively charged dyes (e.g., polyethyleneimine-PEI) allows, visualisation of proteoglycans and provides a detailed description of how proteoglycans are distributed throughout the cartilage matrix. PEI staining was studied by electron and reflection contrast microscopy in human growth plates, osteochondromas and five different proteoglycan-deficient zebrafish mutants displaying one of the following skeletal phenotypes: dackel (dak/ext2), lacking heparan sulphate and identified as a model for human multiple osteochondromas; hi307 (β3gat3), deficient for most glycosaminoglycans; pinscher (pic/slc35b2), presenting with defective sulphation of glycosaminoglycans; hi954 (uxs1), lacking most glycosaminoglycans; and knypek (kny/gpc4), missing the protein core of the glypican-4 proteoglycan. The panel of genetically well-characterized proteoglycan-deficient zebrafish mutants serves as a convincing and comprehensive study model to investigate proteoglycan distribution and the relation of this distribution to the model mutation status. They also provide insight into the distributions and gradients that can be expected in the human homologue. Human growth plate, wild-type zebrafish and fish mutants with mild proteoglycan defects (hi307 and kny) displayed proteoglycans distributed in a gradient throughout the matrix. Although the mutants pic and hi954, which had severely impaired proteoglycan biosynthesis, showed no PEI staining, dak mutants demonstrated reduced PEI staining and no gradient formation. Most chondrocytes from human osteochondromas showed normal PEI staining. However, approximately 10% of tumour chondrocytes were similar to those found in the dak mutant (e.g., lack of PEI gradients). The cells in the reduced PEI-stained areas are likely associated with loss-of-function mutations in the EXT genes, and they might contribute to tumour initiation by disrupting the gradients.
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Affiliation(s)
- Carlos E de Andrea
- Department of Pathology, Leiden University Medical Centre, Leiden, The Netherlands
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58
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Baas S, Sharrow M, Kotu V, Middleton M, Nguyen K, Flanagan-Steet H, Aoki K, Tiemeyer M. Sugar-free frosting, a homolog of SAD kinase, drives neural-specific glycan expression in the Drosophila embryo. Development 2011; 138:553-63. [PMID: 21205799 PMCID: PMC3014640 DOI: 10.1242/dev.055376] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2010] [Indexed: 01/10/2023]
Abstract
Precise glycan structures on specific glycoproteins impart functionalities essential for neural development. However, mechanisms controlling embryonic neural-specific glycosylation are unknown. A genetic screen for relevant mutations in Drosophila generated the sugar-free frosting (sff) mutant that reveals a new function for protein kinases in regulating substrate flux through specific Golgi processing pathways. Sff is the Drosophila homolog of SAD kinase, which regulates synaptic vesicle tethering and neuronal polarity in nematodes and vertebrates. Our Drosophila sff mutant phenotype has features in common with SAD kinase mutant phenotypes in these other organisms, but we detect altered neural glycosylation well before the initiation of embryonic synaptogenesis. Characterization of Golgi compartmentation markers indicates altered colocalization that is consistent with the detected shift in glycan complexity in sff mutant embryos. Therefore, in analogy to synaptic vesicle tethering, we propose that Sff regulates vesicle tethering at Golgi membranes in the developing Drosophila embryo. Furthermore, neuronal sff expression is dependent on transcellular signaling through a non-neural toll-like receptor, linking neural-specific glycan expression to a kinase activity that is induced in response to environmental cues.
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Affiliation(s)
- Sarah Baas
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602-4712, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, B122 Life Sciences Building, Green Street, Athens, GA, 30602-4712, USA
| | - Mary Sharrow
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602-4712, USA
| | - Varshika Kotu
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602-4712, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, B122 Life Sciences Building, Green Street, Athens, GA, 30602-4712, USA
| | - Meg Middleton
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602-4712, USA
| | - Khoi Nguyen
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602-4712, USA
| | - Heather Flanagan-Steet
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602-4712, USA
| | - Kazuhiro Aoki
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602-4712, USA
| | - Michael Tiemeyer
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA, 30602-4712, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, B122 Life Sciences Building, Green Street, Athens, GA, 30602-4712, USA
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59
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Wu ZL, Prather B, Ethen CM, Kalyuzhny A, Jiang W. Detection of specific glycosaminoglycans and glycan epitopes by in vitro sulfation using recombinant sulfotransferases. Glycobiology 2010; 21:625-33. [DOI: 10.1093/glycob/cwq204] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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60
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Chaudhuri P, Harfouche R, Sengupta S. The Bittersweet Promise of Glycobiology. Biomarkers 2010. [DOI: 10.1002/9780470918562.ch5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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61
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Matsumoto K, Irie F, Mackem S, Yamaguchi Y. A mouse model of chondrocyte-specific somatic mutation reveals a role for Ext1 loss of heterozygosity in multiple hereditary exostoses. Proc Natl Acad Sci U S A 2010; 107:10932-7. [PMID: 20534475 PMCID: PMC2890731 DOI: 10.1073/pnas.0914642107] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Multiple hereditary exostoses (MHE) is one of the most common skeletal dysplasias, exhibiting the formation of multiple cartilage-capped bony protrusions (osteochondroma) and characteristic bone deformities. Individuals with MHE carry heterozygous loss-of-function mutations in Ext1 or Ext2, genes which together encode an enzyme essential for heparan sulfate synthesis. Despite the identification of causative genes, the pathogenesis of MHE remains unclear, especially with regard to whether osteochondroma results from loss of heterozygosity of the Ext genes. Hampering elucidation of the pathogenic mechanism of MHE, both Ext1(+/-) and Ext2(+/-) heterozygous mutant mice, which mimic the genetic status of human MHE, are highly resistant to osteochondroma formation, especially in long bones. To address these issues, we created a mouse model in which Ext1 is stochastically inactivated in a chondrocyte-specific manner. We show that these mice develop multiple osteochondromas and characteristic bone deformities in a pattern and a frequency that are almost identical to those of human MHE, suggesting a role for Ext1 LOH in MHE. Surprisingly, however, genotyping and fate mapping analyses reveal that chondrocytes constituting osteochondromas are mixtures of mutant and wild-type cells. Moreover, osteochondromas do not possess many typical neoplastic properties. Together, our results suggest that inactivation of Ext1 in a small fraction of chondrocytes is sufficient for the development of osteochondromas and other skeletal defects associated with MHE. Because the observed osteochondromas in our mouse model do not arise from clonal growth of chondrocytes, they cannot be considered true neoplasms.
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Affiliation(s)
- Kazu Matsumoto
- Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037; and
| | - Fumitoshi Irie
- Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037; and
| | - Susan Mackem
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD 21702
| | - Yu Yamaguchi
- Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037; and
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62
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Ezra N, Tetteh B, Diament M, Jonas AJ, Dickson P. Hereditary multiple exostoses with spine involvement in a 4-year-old boy. Am J Med Genet A 2010; 152A:1264-7. [DOI: 10.1002/ajmg.a.33345] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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63
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Matsumoto Y, Matsumoto K, Irie F, Fukushi JI, Stallcup WB, Yamaguchi Y. Conditional ablation of the heparan sulfate-synthesizing enzyme Ext1 leads to dysregulation of bone morphogenic protein signaling and severe skeletal defects. J Biol Chem 2010; 285:19227-34. [PMID: 20404326 DOI: 10.1074/jbc.m110.105338] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Increasing evidence indicates that heparan sulfate (HS) is an integral component of many morphogen signaling pathways. However, its mechanisms of action appear to be diverse, depending on the type of morphogen and the developmental contexts. To define the function of HS in skeletal development, we conditionally ablated Ext1, which encodes an essential glycosyltransferase for HS synthesis, in limb bud mesenchyme using the Prx1-Cre transgene. These conditional Ext1 mutant mice display severe limb skeletal defects, including shortened and malformed limb bones, oligodactyly, and fusion of joints. In developing limb buds of mutant mice, chondrogenic differentiation of mesenchymal condensations is delayed and impaired, whereas the area of differentiation is diffusely expanded. Correspondingly, the distribution of both bone morphogenic protein (BMP) signaling domains and BMP2 immunoreactivity in the mutant limb mesenchyme is broadened and diffuse. In micromass cultures, chondrogenic differentiation of mutant chondrocytes is delayed, and the responsiveness to exogenous BMPs is attenuated. Moreover, the segregation of the pSmad1/5/8-expressing chondrocytes and fibronectin-expressing perichondrium-like cells surrounding chondrocyte nodules is disrupted in mutant micromass cultures. Together, our results show that HS is essential for patterning of limb skeletal elements and that BMP signaling is one of the major targets for the regulatory role of HS in this developmental context.
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Affiliation(s)
- Yoshihiro Matsumoto
- Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA
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64
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Wong AW, Baginski TK, Reilly DE. Enhancement of DNA uptake in FUT8-deleted CHO cells for transient production of afucosylated antibodies. Biotechnol Bioeng 2010; 106:751-63. [DOI: 10.1002/bit.22749] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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65
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Dziedzic D, Węgrzyn G, Jakóbkiewicz-Banecka J. Impairment of glycosaminoglycan synthesis in mucopolysaccharidosis type IIIA cells by using siRNA: a potential therapeutic approach for Sanfilippo disease. Eur J Hum Genet 2010; 18:200-5. [PMID: 19690584 PMCID: PMC2987185 DOI: 10.1038/ejhg.2009.144] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 06/09/2009] [Accepted: 07/09/2009] [Indexed: 01/29/2023] Open
Abstract
Mucopolysaccharidoses (MPS) are severe inherited metabolic disorders from the group of lysosomal storage diseases. They are caused by deficiency in the activity of enzymes involved in the degradation of glycosaminoglycans (GAGs) and resultant accumulation of these compounds in the cells of patients. Although enzyme replacement therapy has become available for some MPS types (MPS I, MPS II and MPS VI), this treatment is not efficient when neurological symptoms occur, especially in MPS III (Sanfilippo disease). Recent studies indicated that substrate reduction therapy (SRT) may be an effective option for the treatment of neurodegenerative lysosomal storage diseases, including MPS III. However, previous attempts to SRT for MPS III focused on the use of non-specific inhibitors of GAG synthesis. Thus, we aimed to use the small interfering RNA (siRNA) procedure to control expression of particular genes, whose products are involved in GAG synthesis. In this report we show that, in MPS IIIA fibroblasts, we were able to reduce mRNA levels of four genes, XYLT1, XYLT2, GALTI and GALTII, whose products are involved in GAG synthesis. This decrease in levels of transcripts corresponded to a decrease in levels of proteins encoded by them. Moreover, efficiency of GAG production in these fibroblasts was considerably reduced after treatment of the cells with siRNA. These results indicate that efficient reduction of GAG synthesis may be achieved by the use of siRNA.
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Affiliation(s)
- Dariusz Dziedzic
- Department of Molecular Biology, University of Gdańsk, Kładki 24, Gdańsk, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk, Kładki 24, Gdańsk, Poland
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66
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Roles of heparan sulfate in mammalian brain development current views based on the findings from Ext1 conditional knockout studies. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 93:133-52. [PMID: 20807644 DOI: 10.1016/s1877-1173(10)93007-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Development of the mammalian central nervous system proceeds roughly in four major steps, namely the patterning of the neural tube, generation of neurons from neural stem cells and their migration to genetically predetermined destinations, extension of axons and dendrites toward target neurons to form neural circuits, and formation of synaptic contacts. Earlier studies on spatiotemporal expression patterns and in vitro function of heparan sulfate (HS) suggested that HS is functionally involved in various aspects of neural development. Recent studies using knockout of genes involved in HS biosynthesis have provided more physiologically relevant information as to the role of HS in mammalian neural development. This chapter reviews the current understanding of the in vivo function of HS deduced from the phenotypes of conditional Ext1 knockout mice.
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Duelli A, Rönnberg E, Waern I, Ringvall M, Kolset SO, Pejler G. Mast cell differentiation and activation is closely linked to expression of genes coding for the serglycin proteoglycan core protein and a distinct set of chondroitin sulfate and heparin sulfotransferases. THE JOURNAL OF IMMUNOLOGY 2009; 183:7073-83. [PMID: 19915053 DOI: 10.4049/jimmunol.0900309] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Serglycin (SG) proteoglycan consists of a small core protein to which glycosaminoglycans of chondroitin sulfate or heparin type are attached. SG is crucial for maintaining mast cell (MC) granule homeostasis through promoting the storage of various basic granule constituents, where the degree of chondroitin sulfate/heparin sulfation is essential for optimal SG functionality. However, the regulation of the SG core protein expression and of the various chondroitin sulfate/heparin sulfotransferases during MC differentiation and activation are poorly understood. Here we addressed these issues and show that expression of the SG core protein, chondroitin 4-sulfotransferase (C4ST)-1, and GalNAc(4S)-6-O-sulfotransferase (GalNAc4S6ST) are closely linked to MC maturation. In contrast, the expression of chondroitin 6-sulfotransferase correlated negatively with MC maturation. The expression of N-deacetylase/N-sulfotransferase (NDST)-2, a key enzyme in heparin synthesis, also correlated strongly with MC maturation, whereas the expression of the NDST-1 isoform was approximately equal at all stages of maturation. MC activation by either calcium ionophore or IgE ligation caused an up-regulated expression of the SG core protein, C4ST-1, and GalNAc4S6ST, accompanied by increased secretion of chondroitin sulfate as shown by biosynthetic labeling experiments. In contrast, NDST-2 was down-regulated after MC activation, suggesting that MC activation modulates the nature of the glycosaminoglycan chains attached to the SG core protein. Taken together, these data show that MC maturation is associated with the expression of a distinct signature of genes involved in SG proteoglycan synthesis, and that MC activation modulates their expression.
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Affiliation(s)
- Annette Duelli
- Department of Anatomy, Swedish University of Agricultural Sciences, Uppsala 75123, Sweden
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68
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Vanita V, Sperling K, Sandhu HS, Sandhu PS, Singh JR. Novel EXT1 and EXT2 mutations in hereditary multiple exostoses families of Indian origin. Genet Test Mol Biomarkers 2009; 13:43-9. [PMID: 19309273 DOI: 10.1089/gtmb.2008.0055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Hereditary multiple exostosis (HME) is an autosomal dominant bone disorder, characterized by short stature and the presence of multiple benign tumors mainly at the ends of long bones. HME is genetically heterogeneous with two known genes on 8q24 (EXT1) and 11p11 (EXT2), and a third minor locus mapped to 19p (EXT3). The majority of EXT1 and EXT2 mutations result in premature protein truncation and loss of function. MATERIALS AND METHODS We analyzed two autosomal dominant HME families of Indian origin. Linkage analysis using fluorescently labeled microsatellite markers at the candidate gene regions was performed. Mutation analysis was carried out by bidirectional sequencing of purified PCR products. RESULTS We found linkage in one family to EXT1 and in the other family to EXT2. Mutation screening in the EXT1 gene revealed a novel frameshift mutation, a single base deletion in exon 1 (c.142delC). This mutation segregated in all affected members and was absent in the unaffected family members and 60 unrelated controls. In the second family, a previously unreported stop mutation, the substitution c.817C>T, was observed in the EXT2 gene in all affected members and in none of the unaffected family members and 90 unrelated controls. CONCLUSIONS Our findings expand the mutation spectrum of EXT1 and EXT2 and highlight the genetic and phenotypic heterogeneity of HME.
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Affiliation(s)
- Vanita Vanita
- Centre for Genetic Disorders, Guru Nanak Dev University, Amritsar, India.
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Narvid J, Gorno-Tempini ML, Slavotinek A, Dearmond SJ, Cha YH, Miller BL, Rankin K. Of brain and bone: the unusual case of Dr. A. Neurocase 2009; 15:190-205. [PMID: 20183548 PMCID: PMC2997763 DOI: 10.1080/13554790802632967] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Frontotemporal dementia (FTD) is a clinical syndrome characterized by progressive decline in social conduct and a focal pattern of frontal and temporal lobe damage. Its biological basis is still poorly understood but the focality of the brain degeneration provides a powerful model to study the cognitive and anatomical basis of social cognition. Here, we present Dr. A, a patient with a rare hereditary bone disease (hereditary multiple exostoses) and FTD (pathologically characterized as Pick's disease), who presented with a profound behavioral disturbance characterized by acquired sociopathy. We conducted a detailed genetic, pathological, neuroimaging and cognitive study, including a battery of tests designed to investigate Dr. A's abilities to understand emotional cues and to infer mental states and intentions to others (theory of mind). Dr. A's genetic profile suggests the possibility that a mutation causing hereditary multiple exostoses, Ext2, may play a role in the pattern of neurodegeneration in frontotemporal dementia since knockout mice deficient in the Ext gene family member, Ext1, show severe CNS defects including loss of olfactory bulbs and abnormally small cerebral cortex. Dr. A showed significant impairment in emotion comprehension, second order theory of mind, attribution of intentions, and empathy despite preserved general cognitive abilities. Voxel-based morphometry on structural MRI images showed significant atrophy in the medial and right orbital frontal and anterior temporal regions with sparing of dorsolateral frontal cortex. This case demonstrates that social and emotional dysfunction in FTD can be dissociated from preserved performance on classic executive functioning tasks. The specific pattern of anatomical damage shown by VBM emphasizes the importance of the network including the superior medial frontal gyrus as well as temporal polar areas, in regulation of social cognition and theory of mind. This case provides new evidence regarding the neural basis of social cognition and suggests a possible genetic link between bone disease and FTD.
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Affiliation(s)
- J Narvid
- Department of Neurology, Memory and Aging Center, University of California, San Francisco, CA 94143, USA
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70
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Molecular analysis of heparan sulfate biosynthetic enzyme machinery and characterization of heparan sulfate structure in Nematostella vectensis. Biochem J 2009; 419:585-93. [DOI: 10.1042/bj20082081] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
HS (heparan sulfate) proteoglycans are key regulators of vital processes in the body. HS chains with distinct sequences bind to various protein ligands, such as growth factors and morphogens, and thereby function as important regulators of protein gradient formation and signal transduction. HS is synthesized through the concerted action of many different ER (endoplasmic reticulum) and Golgi-resident enzymes. In higher organisms, many of these enzymes occur in multiple isoforms that differ in substrate specificity and spatial and temporal expression. In order to investigate how the structural complexity of HS has evolved, in the present study we focused on the starlet sea anemone (Nematostella vectensis), which belongs to the Anthozoa, which are considered to have retained many ancestral features. Members of all of the enzyme families involved in the generation and modification of HS were identified in Nematostella. Our results show that the enzymes are highly conserved throughout evolution, but the number of isoforms varies. Furthermore, the HS polymerases [Ext (exostosin) enzymes Ext1, Ext2 and Ext-like3] represent distinct subgroups, indicating that these three genes have already been present in the last common ancestor of Cnidaria and Bilateria. In situ hybridization showed up-regulation of certain enzymes in specific areas of the embryo at different developmental stages. The specific mRNA expression pattern of particular HS enzymes implies that they may play a specific role in HS modifications during larval development. Finally, biochemical analysis of Nematostella HS demonstrates that the sea anemone synthesizes a polysaccharide with a unique structure.
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71
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Takahashi I, Noguchi N, Nata K, Yamada S, Kaneiwa T, Mizumoto S, Ikeda T, Sugihara K, Asano M, Yoshikawa T, Yamauchi A, Shervani NJ, Uruno A, Kato I, Unno M, Sugahara K, Takasawa S, Okamoto H, Sugawara A. Important role of heparan sulfate in postnatal islet growth and insulin secretion. Biochem Biophys Res Commun 2009; 383:113-8. [PMID: 19336225 DOI: 10.1016/j.bbrc.2009.03.140] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2009] [Accepted: 03/24/2009] [Indexed: 01/08/2023]
Abstract
Heparan sulfate (HS) binds with several signaling molecules and regulates ligand-receptor interactions, playing an essential role in embryonic development. Here we showed that HS was intensively expressed in pancreatic islet beta-cells after 1 week of age in mice. The enzymatic removal of HS in isolated islets resulted in attenuated glucose-induced insulin secretion with a concomitant reduction in gene expression of several key components in the insulin secretion machinery. We further depleted islet HS by inactivating the exostosin tumor-like 3 gene specifically in beta-cells. These mice exhibited abnormal islet morphology with reduced beta-cell proliferation after 1 week of age and glucose intolerance due to defective insulin secretion. These results demonstrate that islet HS is involved in the regulation of postnatal islet maturation and required to ensure normal insulin secretion.
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Affiliation(s)
- Iwao Takahashi
- Department of Advanced Biological Sciences for Regeneration, Tohoku University Graduate School of Medicine, Sendai, Japan
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72
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Bret C, Hose D, Reme T, Sprynski AC, Mahtouk K, Schved JF, Quittet P, Rossi JF, Goldschmidt H, Klein B. Expression of genes encoding for proteins involved in heparan sulphate and chondroitin sulphate chain synthesis and modification in normal and malignant plasma cells. Br J Haematol 2009; 145:350-68. [PMID: 19298595 DOI: 10.1111/j.1365-2141.2009.07633.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Syndecan-1 is a proteoglycan that concentrates heparin-binding factors on the surface of multiple myeloma cells, and probably plays a major role in multiple myeloma biology. As heparan sulphate and chondroitin sulphate are the bioactive components of syndecan-1, we analysed the signature of genes encoding 100 proteins involved in synthesis of these chains, i.e. from precursor uptake to post-translational modifications, using Affymetrix microarrays. The expression of enzymes required for heparan sulphate and chondroitin sulphate biosynthesis was shown to increase in parallel with syndecan-1 expression, throughout the differentiation of memory B cells into plasmablasts and normal bone marrow plasma cells. Sixteen genes were significantly different between normal and malignant plasma cells, nine of these genes -EXT2, CHSY3, CSGALNACT1, HS3ST2, HS2ST1, CHST11, CSGALNACT2, HPSE, SULF2 - encode proteins involved in glycosaminoglycan chain synthesis or modifications. Kaplan-Meier analysis was performed in two independent series of patients: B4GALT7, CSGALNACT1, HS2ST1 were associated with a good prognosis whereas EXT1 was linked to a bad prognosis. This study provides an overall picture of the major genes encoding for proteins involved in heparan sulphate and chondroitin sulphate synthesis and modifications that can be implicated in normal and malignant plasma cells.
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Affiliation(s)
- Caroline Bret
- INSERM U847, Equipe Labellisée LIGUE 2006, Université Montpellier, UFR Méldecine, Montpellier, France
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73
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Glycosylation diseases: quo vadis? Biochim Biophys Acta Mol Basis Dis 2008; 1792:925-30. [PMID: 19061954 DOI: 10.1016/j.bbadis.2008.11.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 11/03/2008] [Accepted: 11/06/2008] [Indexed: 12/29/2022]
Abstract
About 250 to 500 glycogenes (genes that are directly involved in glycan assembly) are in the human genome representing about 1-2% of the total genome. Over 40 human congenital diseases associated with glycogene mutations have been described to date. It is almost certain that the causative glycogene mutations for many more congenital diseases remain to be discovered. Some glycogenes are involved in the synthesis of only a specific protein and/or a specific class of glycan whereas others play a role in the biosynthesis of more than one glycan class. Mutations in the latter type of glycogene result in complex clinical phenotypes that present difficult diagnostic problems to the clinician. In order to understand in biochemical terms the clinical signs and symptoms of a patient with a glycogene mutation, one must understand how the glycogene works. That requires, first of all, determination of the target protein or proteins of the glycogene followed by an understanding of the role, if any, of the glycogene-dependent glycan in the functions of the protein. Many glycogenes act on thousands of glycoproteins. There are unfortunately no general methods to identify all the potentially large number of glycogene target proteins and which of these proteins are responsible for the mutant phenotypes. Whereas biochemical methods have been highly successful in the discovery of glycogenes responsible for many congenital diseases, it has more recently been necessary to use other methods such as homozygosity mapping. Accurate diagnosis of many recently discovered diseases has become difficult and new diagnostic procedures must be developed. Last but not least is the lack of effective treatment for most of these children and of animal models that can be used to test new therapies.
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Abstract
Increasing evidence indicates that many signaling pathways involve not only ligands and receptors but also various types of coreceptors and matrix components as additional layers of regulation. Signaling by Eph receptors and their ephrin ligands plays a key role in a variety of biological processes, such as axon guidance and topographic map formation, synaptic plasticity, angiogenesis, and cancer. Little is known about whether the ephrin-Eph receptor signaling system is subject to such additional layers of regulation. Here, we show that ephrin-A3 binds to heparan sulfate, and that the presence of cell surface heparan sulfate is required for the full biological activity of ephrin-A3. Among the ephrins tested, including ephrin-A1, -A2, -A5, -B1, and -B2, only ephrin-A3 binds heparin or heparan sulfate. Ephrin-A3-dependent EphA receptor activation is reduced in mutant cells that are defective in heparan sulfate synthesis, in wild-type cells from which cell surface heparan sulfate has been removed, and in the hippocampus of conditional knockout mice defective in heparan sulfate synthesis. Ephrin-A3-dependent cell rounding is impaired in CHO cells lacking heparan sulfate, and cortical neurons lacking heparan sulfate exhibit impaired growth cone collapse. In contrast, cell rounding and growth cone collapse in response to ephrin-A5, which does not bind heparan sulfate, are not affected by the absence of heparan sulfate. These results show that heparan sulfate modulates ephrin/Eph signaling and suggest a physiological role for heparan sulfate proteoglycans in the regulation of ephrin-A3-dependent biological processes.
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75
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Expression of the novel Golgi protein GoPro49 is developmentally regulated during mesenchymal differentiation. Dev Dyn 2008; 237:2243-55. [DOI: 10.1002/dvdy.21646] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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76
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Clément A, Wiweger M, von der Hardt S, Rusch MA, Selleck SB, Chien CB, Roehl HH. Regulation of zebrafish skeletogenesis by ext2/dackel and papst1/pinscher. PLoS Genet 2008; 4:e1000136. [PMID: 18654627 PMCID: PMC2453328 DOI: 10.1371/journal.pgen.1000136] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Accepted: 06/20/2008] [Indexed: 11/28/2022] Open
Abstract
Mutations in human Exostosin genes (EXTs) confer a disease called Hereditary Multiple Exostoses (HME) that affects 1 in 50,000 among the general population. Patients with HME have a short stature and develop osteochondromas during childhood. Here we show that two zebrafish mutants, dackel (dak) and pinscher (pic), have cartilage defects that strongly resemble those seen in HME patients. We have previously determined that dak encodes zebrafish Ext2. Positional cloning of pic reveals that it encodes a sulphate transporter required for sulphation of glycans (Papst1). We show that although both dak and pic are required during cartilage morphogenesis, they are dispensable for chondrocyte and perichondral cell differentiation. They are also required for hypertrophic chondrocyte differentiation and osteoblast differentiation. Transplantation analysis indicates that dak−/− cells are usually rescued by neighbouring wild-type chondrocytes. In contrast, pic−/− chondrocytes always act autonomously and can disrupt the morphology of neighbouring wild-type cells. These findings lead to the development of a new model to explain the aetiology of HME. Hereditary Multiple Exostoses is a disease that causes the formation of benign bone tumours in children. Besides causing severe skeletal deformity, the bone tumours can compress nerves or other tissue resulting in chronic pain. Although the tumours can usually be surgically removed, they sometimes recur or are in positions that prevent surgery. We have identified two strains of zebrafish whose offspring have skeletal defects that resemble those of patients with Hereditary Multiple Exostoses. We have found that each strain carries a mutated form of an essential gene. Importantly, these two genes are also found in humans, and thus by analysing their function in zebrafish, we may shed light on their role in humans. Our study has elucidated the roles of these genes during normal skeletal development and has allowed us to generate a model for how genetic changes give rise to bone tumours in humans.
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Affiliation(s)
- Aurélie Clément
- MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Malgorzata Wiweger
- MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | | | - Melissa A. Rusch
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Scott B. Selleck
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Chi-Bin Chien
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
- Brain Institute, University of Utah, Salt Lake City, Utah, United States of America
| | - Henry H. Roehl
- MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Sheffield, United Kingdom
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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Hydrogen peroxide as a potential mediator of the transcriptional regulation of heparan sulphate biosynthesis in keratinocytes. Cell Mol Biol Lett 2008; 13:475-92. [PMID: 18463796 PMCID: PMC6275676 DOI: 10.2478/s11658-008-0016-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Accepted: 02/07/2008] [Indexed: 11/20/2022] Open
Abstract
Ionizing radiation is one of the types of oxidative stress that has a number of damaging effects on cutaneous tissues. One of the histological features of radiation-induced cutaneous fibrosis is the accumulation of extracellular matrix (ECM) components, including heparan sulfate proteoglycan (HSPG), which are required for the repair of tissue damage, and operate by interacting with a variety of growth factors. In this study, we established a model of human HaCaT keratinocytes overexpressing anti-oxidative enzyme genes to elucidate the mechanism of oxidative stress leading to the accumulation of HSPG and the role of its accumulation. Catalase overexpression induced an increase in anti-HS antibody (10E4) epitope expression in these cells. Western blotting showed that the smeared bands of HSPG were obviously shifted to a higher molecular weight in the catalase transfectants due to glycosylation. After heparitinase I treatment, the core proteins of HSPG were expressed in the catalase transfectants to almost the same extent as in the control cells. In addition, the transcript levels of all the enzymes required for the synthesis of the heparan sulfate chain were estimated in the catalase transfectant clones. The levels of five enzyme transcripts — xylosyltransferase-II (XT-II), EXTL2, D-glucuronyl C5-epimerase (GLCE), HS2-O-sulfotransferase (HS2ST), and HS6-O-sulfotransferase (HS6ST) — were significantly increased in the transfectants. Moreover, hydrogen peroxide was found to down-regulate the levels of these enzymes. By contrast, siRNA-mediated repression of catalase decreased 10E4 epitope expression, the transcript level of HS2ST1, and the growth rate of HaCaT cells. These findings suggested that peroxide-mediated transcriptional regulation of HS metabolism-related genes modified the HS chains in the HaCaT keratinocytes.
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78
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Foroughmand AM, Galehdari H, Rasouli M, Mohammadian G, Mohammadi M. Novel mutation in the EXT-1 gene in an Iranian family affected with hereditary multiple exostoses. Pak J Biol Sci 2008; 11:1037-41. [PMID: 18810975 DOI: 10.3923/pjbs.2008.1037.1041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Identification of casual mutations in Hereditary Multiple Exostoses (HME) is important because of similar conditions in which multiple exostoses occur. Therefore mutation analysis can help to confirm the clinical diagnosis and to improve the management of therapy. HME is an inherited disorder of bone growth. HME can be referred to by various names such as Heredity Multiple Exostoses, Hereditary Multiple Osteochondromata, Multiple Carthaginous Exostoses, etc. People who have HME grow exostoses, or bony bumps, on their bones which can vary in size, location and number depending on the individual. HME is inherited in an autosomal dominant manner with an estimated prevalence of 1/50,000 in western countries. At least three loci (EXT1, EXT2 and EXT3) thought to be involved in this skeletal disease. Approximately 90% of affected families possess mutations in the coding regions of EXT1 and EXT2 genes and the majority of these mutations cause loss of function. EXT1 and EXT2 genes encode related members of a putative tumor suppressor family. In this first report from Iran we identified a frame shift mutation (1100-1101 insA) in exon 3 of EXT1 gene in a family being suspicious of HME. This mutation leads to a premature stop codon and previously not described. Additionally, we have found an unreported silent mutation in the exon six of EXT1 gene with uncertain significance.
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79
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The role of GlcNAc in formation and function of extracellular matrices. Comp Biochem Physiol B Biochem Mol Biol 2008; 149:215-26. [DOI: 10.1016/j.cbpb.2007.10.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 10/17/2007] [Accepted: 10/17/2007] [Indexed: 01/27/2023]
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80
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Busse M, Feta A, Presto J, Wilén M, Grønning M, Kjellén L, Kusche-Gullberg M. Contribution of EXT1, EXT2, and EXTL3 to heparan sulfate chain elongation. J Biol Chem 2007; 282:32802-10. [PMID: 17761672 DOI: 10.1074/jbc.m703560200] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The exostosin (EXT) family of genes encodes glycosyltransferases involved in heparan sulfate biosynthesis. Five human members of this family have been cloned to date: EXT1, EXT2, EXTL1, EXTL2, and EXTL3. EXT1 and EXT2 are believed to form a Golgi-located hetero-oligomeric complex that catalyzes the chain elongation step in heparan sulfate biosynthesis, whereas the EXTL proteins exhibit overlapping glycosyl-transferase activities in vitro, so that it is not apparent what reactions they catalyze in vivo. We used gene-silencing strategies to investigate the roles of EXT1, EXT2, and EXTL3 in heparan sulfate chain elongation. Small interfering RNAs (siRNAs) directed against the human EXT1, EXT2, or EXTL3 mRNAs were introduced into human embryonic kidney 293 cells. Compared with cells transfected with control siRNA, those transfected with EXT1 or EXT2 siRNA synthesized shorter heparan sulfate chains, and those transfected with EXTL3 siRNA synthesized longer chains. We also generated human cell lines overexpressing the EXT proteins. Overexpression of EXT1 resulted in increased HS chain length, which was even more pronounced in cells coexpressing EXT2, whereas overexpression of EXT2 alone had no detectable effect on heparan sulfate chain elongation. Mutations in either EXT1 or EXT2 are associated with hereditary multiple exostoses, a human disorder characterized by the formation of cartilage-capped bony outgrowths at the epiphyseal growth plates. To further investigate the role of EXT2, we generated human cell lines overexpressing mutant EXT2. One of the mutations, EXT2-Y419X, resulted in a truncated protein. Interestingly, the capacity of wild type EXT2 to enhance HS chain length together with EXT1 was not shared by the EXT2-Y419X mutant.
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Affiliation(s)
- Marta Busse
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, Bergen, Norway
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81
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Sismey-Ragatz AE, Green DE, Otto NJ, Rejzek M, Field RA, DeAngelis PL. Chemoenzymatic synthesis with distinct Pasteurella heparosan synthases: monodisperse polymers and unnatural structures. J Biol Chem 2007; 282:28321-28327. [PMID: 17627940 DOI: 10.1074/jbc.m701599200] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heparosan (-GlcUA-beta1,4-GlcNAc-alpha1,4-)(n) is a member of the glycosaminoglycan polysaccharide family found in the capsule of certain pathogenic bacteria as well as the precursor for the vertebrate polymers, heparin and heparan sulfate. The two heparosan synthases from the Gram-negative bacteria Pasteurella multocida, PmHS1 and PmHS2, were efficiently expressed and purified using maltose-binding protein fusion constructs. These relatively homologous synthases displayed distinct catalytic characteristics. PmHS1, but not PmHS2, was able to produce large molecular mass (100-800 kDa) monodisperse polymers in synchronized, stoichiometrically controlled reactions in vitro. PmHS2, but not PmHS1, was able to utilize many unnatural UDP-sugar analogs (including substrates with acetamido-containing uronic acids or longer acyl chain hexosamine derivatives) in vitro. Overall these findings reveal potential differences in the active sites of these two Pasteurella enzymes. In the future, these catalysts should allow the creation of a variety of heparosan and heparinoids with utility for medical applications.
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Affiliation(s)
- Alison E Sismey-Ragatz
- Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Dixy E Green
- Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Nigel J Otto
- Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Martin Rejzek
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, United Kingdom
| | - Robert A Field
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, United Kingdom
| | - Paul L DeAngelis
- Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104.
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Dasgupta U, Dixit BL, Rusch M, Selleck S, The I. Functional conservation of the human EXT1 tumor suppressor gene and its Drosophila homolog tout velu. Dev Genes Evol 2007; 217:555-61. [PMID: 17610078 DOI: 10.1007/s00427-007-0163-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Accepted: 05/16/2007] [Indexed: 11/24/2022]
Abstract
Heparan sulfate proteoglycans play a vital role in signaling of various growth factors in both Drosophila and vertebrates. In Drosophila, mutations in the tout velu (ttv) gene, a homolog of the mammalian EXT1 tumor suppressor gene, leads to abrogation of glycosaminoglycan (GAG) biosynthesis. This impairs distribution and signaling activities of various morphogens such as Hedgehog (Hh), Wingless (Wg), and Decapentaplegic (Dpp). Mutations in members of the exostosin (EXT) gene family lead to hereditary multiple exostosis in humans leading to bone outgrowths and tumors. In this study, we provide genetic and biochemical evidence that the human EXT1 (hEXT1) gene is conserved through species and can functionally complement the ttv mutation in Drosophila. The hEXT1 gene was able to rescue a ttv null mutant to adulthood and restore GAG biosynthesis.
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Affiliation(s)
- Ujjaini Dasgupta
- Program in Gene Function and Expression, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
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83
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Kobayashi T, Habuchi H, Tamura K, Ide H, Kimata K. Essential role of heparan sulfate 2-O-sulfotransferase in chick limb bud patterning and development. J Biol Chem 2007; 282:19589-97. [PMID: 17493930 DOI: 10.1074/jbc.m610707200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The interactions of heparan sulfate (HS) with heparin-binding growth factors, such as fibroblast growth factors (FGFs), depend greatly on the chain structures. O-Sulfations at various positions on the chain are major factors determining HS structure; therefore, O-sulfation patterns may play a crucial role in controlling the developmental and morphogenetic processes of various tissues and organs by spatiotemporally regulating the activities of heparin-binding growth factors. In a previous study, we found that HS-2-O-sulfotransferase is strongly expressed throughout the mesoderm of chick limb buds during the early stages of development. Here we show that inhibition of HS-2-O-sulfotransferase in the prospective limb region by small inhibitory RNA resulted in the truncation of limb buds and reduced Fgf-8 expression in the apical ectodermal ridge. The treatment also reduced Fgf-10 expression in the mesenchyme. Moreover 2-O-sulfated HS, normally abundant in the basement membranes and mesoderm under ectoderm in limb buds, was significantly reduced in the treated buds. Phosphorylation levels of ERK and Akt were up-regulated in such truncated buds. Thus, we have shown for the first time that 2-O-sulfation of HS is essential for the FGF signaling required for limb bud development and outgrowth.
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Affiliation(s)
- Takashi Kobayashi
- Institute for Molecular Science of Medicine, Aichi Medical University, Nagakute, Aichi 480-1195, Japan
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84
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Matsumoto Y, Irie F, Inatani M, Tessier-Lavigne M, Yamaguchi Y. Netrin-1/DCC signaling in commissural axon guidance requires cell-autonomous expression of heparan sulfate. J Neurosci 2007; 27:4342-50. [PMID: 17442818 PMCID: PMC6672322 DOI: 10.1523/jneurosci.0700-07.2007] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
There is increasing evidence that heparan sulfate (HS) plays an essential role in various axon guidance processes. These observations, however, have not addressed whether HS is required cell autonomously as an axonal coreceptor or as an environmental factor that modulates the localization of guidance molecules in the terrain in which growing axons navigate. Here we demonstrate that netrin-1-mediated commissural axon guidance requires cell-autonomous expression of HS in commissural neurons in vivo. We used the Wnt1-Cre transgene to drive region-specific ablation of Ext1, which encodes an enzyme essential for HS synthesis, in the dorsal part of the spinal cord. Remarkably, Wnt1-Cre-mediated ablation of Ext1 causes commissural axon pathfinding defects that share similarities with those of Netrin-1-deficient and DCC (deleted in colorectal cancer)-deficient mice. Neither Ext1-deficient dorsal spinal cord explants nor wild-type explants in which HS expression was ablated could extend axons in response to netrin-1. Intracellular signaling downstream of netrin-1 and DCC was defective in Ext1-deficient commissural neurons and in DCC-transfected HEK293T cells from which HS was removed. These results demonstrate that the expression of HS by commissural neurons is essential for these neurons to transduce netrin-1 signals, thus providing evidence for a cell-autonomous role of HS in netrin-1/DCC-mediated axon guidance.
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Affiliation(s)
| | - Fumitoshi Irie
- Developmental Neurobiology and
- Glycobiology Programs, Burnham Institute for Medical Research, La Jolla, California 92037, and
| | | | | | - Yu Yamaguchi
- Developmental Neurobiology and
- Glycobiology Programs, Burnham Institute for Medical Research, La Jolla, California 92037, and
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85
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Hameetman L, David G, Yavas A, White SJ, Taminiau AHM, Cleton-Jansen AM, Hogendoorn PCW, Bovée JVMG. Decreased EXT expression and intracellular accumulation of heparan sulphate proteoglycan in osteochondromas and peripheral chondrosarcomas. J Pathol 2007; 211:399-409. [PMID: 17226760 DOI: 10.1002/path.2127] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mutational inactivation of EXT1 or EXT2 is the cause of hereditary multiple osteochondromas. These genes function in heparan sulphate proteoglycan (HSPG) biosynthesis in the Golgi apparatus. Loss of heterozygosity of the EXT1 locus at 8q24 is frequently found in solitary osteochondromas, whereas somatic mutations are rarely found. We investigated the expression of EXT1 and EXT2 (quantitative RT-PCR) and of different HSPGs (immunohistochemistry) in solitary and hereditary osteochondromas and in cases with malignant progression to secondary peripheral chondrosarcoma, in relation to possible mutations and promoter methylation. The mutation status of patients with multiple osteochondromas correlated with decreased EXT1 or EXT2 expression found in their resected tumours. We could not show somatic point mutations or promoter hypermethylation in 17 solitary tumours; however, EXT1 expression was decreased in 15 cases, whereas EXT2 was not. Intracellular accumulation of syndecan-2 and heparan sulphate-bearing isoforms of CD44 (CD44v3) was found in most tumours, which concentrated in the Golgi apparatus as shown by confocal microscopy. This contrasted with the extracellular expression found in normal growth plates. In conclusion, mutational inactivation of either EXT1 or EXT2 leads to loss of mRNA expression of the corresponding gene. We hypothesize that loss of EXT expression disrupts the function of the EXT1/2 complex in HSPG biosynthesis, resulting in the intracellular accumulation of HSPG core proteins that we found in these tumours.
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Affiliation(s)
- L Hameetman
- Department of Pathology, Leiden University Medical Centre, Leiden, The Netherlands
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86
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Hameetman L, Szuhai K, Yavas A, Knijnenburg J, van Duin M, van Dekken H, Taminiau AHM, Cleton-Jansen AM, Bovée JVMG, Hogendoorn PCW. The role of EXT1 in nonhereditary osteochondroma: identification of homozygous deletions. J Natl Cancer Inst 2007; 99:396-406. [PMID: 17341731 DOI: 10.1093/jnci/djk067] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Multiple osteochondromas is a hereditary syndrome that is characterized by the formation of cartilage-capped bony neoplasms (osteochondromas), for which exostosis (multiple)-1 (EXT1) has been identified as a causative gene. However, 85% of all osteochondromas present as solitary (nonhereditary) lesions in which somatic mutations in EXT1 are extremely rare, but loss of heterozygosity and clonal rearrangement of 8q24 (the chromosomal locus of EXT1) are common. We examined whether EXT1 might act as a classical tumor suppressor gene for nonhereditary osteochondromas. METHODS Eight nonhereditary osteochondromas were subjected to high-resolution array-based comparative genomic hybridization (array-CGH) analysis for chromosome 8q. The array-CGH results were validated by subjecting tumor DNA to multiple ligation-dependent probe amplification (MLPA) analysis for EXT1. EXT1 locus-specific fluorescent in situ hybridization (FISH) was performed on nuclei isolated from the three tissue components of osteochondroma (cartilage cap, perichondrium, bony stalk) to examine which parts of the tumor are of clonal origin. RESULTS Array-CGH analysis of tumor DNA revealed that all eight osteochondromas had a large deletion of 8q; five tumors had an additional small deletion of the other allele of 8q that contained the EXT1 gene. MLPA analysis of tumor DNA confirmed these findings and identified two additional deletions that were smaller than the limit of resolution of array-CGH. FISH analysis of the cartilage cap, perichondrium, and bony stalk showed that these homozygous EXT1 deletions were present only in the cartilage cap of osteochondroma. CONCLUSION EXT1 functions as a classical tumor suppressor gene in the cartilage cap of nonhereditary osteochondromas.
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Affiliation(s)
- Liesbeth Hameetman
- Department of Pathology, Leiden University Medical Center, PO Box 9600 L1-Q, 2300 RC Leiden, The Netherlands
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87
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Aoki K, Perlman M, Lim JM, Cantu R, Wells L, Tiemeyer M. Dynamic developmental elaboration of N-linked glycan complexity in the Drosophila melanogaster embryo. J Biol Chem 2007; 282:9127-42. [PMID: 17264077 DOI: 10.1074/jbc.m606711200] [Citation(s) in RCA: 216] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The structural diversity of glycoprotein N-linked oligosaccharides is determined by the expression and regulation of glycosyltransferase activities and by the availability of the appropriate acceptor/donor substrates. Cells in different tissues and in different developmental stages utilize these control points to manifest unique glycan expression patterns in response to their surroundings. The activity of a Toll-like receptor, called Tollo/Toll-8, induces a pattern of incompletely defined, but neural specific, glycan expression in the Drosophila embryo. Understanding the full extent of the changes in glycan expression that result from altered Tollo/Toll-8 signaling requires characterization of the complete N-linked glycan profile of both wild-type and mutant embryos. N-Linked glycans harvested from wild-type or mutant embryos were subjected to direct structural analysis by analytic and preparative high pressure liquid chromatography, by multidimensional mass spectrometry, and by exoglycosidase digestion, revealing a predominance of high mannose and paucimannose glycans. Di-, mono-, and nonfucosylated forms of hybrid, complex biantennary, and triantennary glycans account for 12% of the total wild-type glycan profile. Two sialylated glycans bearing N-acetylneuraminic acid were detected, the first direct demonstration of this modification in Drosophila. Glycan profiles change during normal development consistent with increasing alpha-mannosidase II and core fucosyl-transferase enzyme activities, and with decreasing activity of the Fused lobes processing hexosaminidase. In tollo/toll-8 mutants, a dramatic, expected loss of difucosylated glycans is accompanied by unexpected decreases in monofucosylated and nonfucosylated hybrid glycans and increases in some nonfucosylated paucimannose and biantennary glycans. Therefore, tollo/toll-8 signaling influences flux through several processing steps that affect the maturation of N-linked glycans.
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Affiliation(s)
- Kazuhiro Aoki
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA
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88
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Jiao X, Billings PC, O'Connell MP, Kaplan FS, Shore EM, Glaser DL. Heparan Sulfate Proteoglycans (HSPGs) Modulate BMP2 Osteogenic Bioactivity in C2C12 Cells. J Biol Chem 2007; 282:1080-6. [PMID: 17020882 DOI: 10.1074/jbc.m513414200] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cell surface heparan sulfate proteoglycans (HSPGs) have been implicated in bone morphogenetic protein (BMP)-mediated morphogenesis by regulating BMP activity and gradient formation. However, the direct role of HSPGs in BMP signaling is poorly understood. Here we show that HSPGs directly regulate BMP2-mediated transdifferentiation of C2C12 myoblasts into osteoblasts. HSPGs sequester BMP2 at the cell surface and mediate BMP2 internalization. Depletion of cell surface HSPGs by heparinase III treatment or decreased glycosaminoglycan chain sulfation with sodium chlorate enhances BMP2 morpho-genetic bioactivity. The addition of exogenous heparin, a widely used anticoagulant, reduced BMP2 signaling. Our results suggest that cell surface HSPGs mediate BMP2 internalization and modulate BMP2 osteogenic activity.
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Affiliation(s)
- Xiangyang Jiao
- Center For Research in Fibrodysplasia Ossificans Progressiva (FOP) and Related Disorders and the Department of Orthopaedics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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89
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90
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Abstract
Salivary gland branching morphogenesis involves coordinated cell growth, proliferation, differentiation, migration, apoptosis, and interaction of epithelial, mesenchymal, endothelial, and neuronal cells. The ex vivo analysis of embryonic mouse submandibular glands, which branch so reproducibly and beautifully in culture, is a powerful tool to investigate the molecular mechanisms regulating epithelium-mesenchyme interactions during development. The more recent analysis of genetically modified mice provides insight into the genetic regulation of branching morphogenesis. The review begins, as did the field historically, focusing on the role of the extracellular matrix (ECM), and its components such as glycosaminoglycans, collagens, and laminins. Following sections describe the modification of the ECM by proteases and the role of cell-matrix and cell-cell receptors. The review then focuses on two major families of growth factors implicated in salivary gland development, the fibroblast growth factors (FGFs) and the epidermal growth factors (EGFs). The salivary gland phenotypes in mice with genetic modification of FGFs and their receptors highlight the central role of FGFs during salivary gland branching morphogenesis. A broader section mentions other molecules implicated from analysis of the phenotypes of genetically modified mice or organ culture experiments. The review concludes with speculation on some future areas of research.
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Affiliation(s)
- Vaishali N Patel
- Matrix and Morphogenesis Unit, Craniofacial Developmental Biology and Regeneration Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, 30 Convent Dr Bethesda, MD 20892, USA
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91
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Gomes RR, Van Kuppevelt TH, Farach-Carson MC, Carson DD. Spatiotemporal distribution of heparan sulfate epitopes during murine cartilage growth plate development. Histochem Cell Biol 2006; 126:713-22. [PMID: 16835755 DOI: 10.1007/s00418-006-0203-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2006] [Indexed: 10/24/2022]
Abstract
Heparan sulfate proteoglycans (HSPGs) are abundant in the pericellular matrix of both developing and mature cartilage. Increasing evidence suggests the action of numerous chondroregulatory molecules depends on HSPGs. In addition to specific functions attributed to their core protein, the complexity of heparan sulfate (HS) synthesis provides extraordinary structural and functional heterogeneity. Understanding the interactions of chondroregulatory molecules with HSPGs and their subsequent outcomes has been limited by the absence of a detailed analysis of HS species in cartilage. In this study, we characterize the distribution and variety of HS species in developing cartilage of normal mice. Cryo-sections of femur and tibia from normal mouse embryos were evaluated using immunostaining techniques. A panel of unique phage display antibodies specific to particular HS species were employed and visualized with secondary antibodies conjugated to Alexa-fluor dyes. Confocal microscopy demonstrates that HS species are dynamic structures within developing growth plate cartilage and the perichondrium. GlcNS6S-IdoUA2S-GlcNS6S species are down regulated and localization of GlcNS6S-IdoUA-GlcNS6S species within the hypertrophic zone of the growth plate is lost during normal development. Regional differences in HS structures are present within developing growth plates, implying that interactions with and responses to HS-binding proteins also may display regional specialization.
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Affiliation(s)
- Ronald R Gomes
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
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92
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Barré L, Venkatesan N, Magdalou J, Netter P, Fournel-Gigleux S, Ouzzine M. Evidence of calcium‐dependent pathway in the regulation of human β1,3‐glucuronosyltransferase‐1 (GlcAT‐I) gene expression: a key enzyme in proteoglycan synthesis. FASEB J 2006; 20:1692-4. [PMID: 16807373 DOI: 10.1096/fj.05-5073fje] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The importance of heparan- and chondroitin-sulfate proteoglycans in physiological and pathological processes led to the investigation of the regulation of beta1,3-glucuronosyltransferase I (GlcAT-I), responsible for the completion of glycosaminoglycan-protein linkage tetrasaccharide, a key step prior to polymerization of chondroitin- and heparan-sulfate chains. We have cloned and functionally characterized GlcAT-I 5'-flanking regulatory region. Mutation analysis and electrophoretic mobility shift assays demonstrated the importance of Sp1 motif located at -65/-56 position in promoter activity. Furthermore, we found that elevation of intracellular calcium concentration by the calcium ionophore ionomycin stimulated GlcAT-I gene expression as well as glycosaminoglycan chain synthesis in HeLa cells. Bisanthracycline, an anti-Sp1 compound, inhibited GlcAT-I basal promoter activity and suppressed ionomycin induction, suggesting the importance of Sp1 in calcium induction of GlcAT-I gene expression. Nuclear protein extracts from ionomycin-induced cells exhibited an increased DNA binding of Sp1 factor to the consensus sequence at position -65/-56. Signaling pathway analysis and MEK inhibition studies revealed the important role of p42/p44 MAPK in the stimulation of GlcAT-I promoter activity by ionomycin. The present study identifies, for the first time, GlcAT-I as a target of calcium-dependent signaling pathway and evidences the critical role of Sp1 transcription factor in the activation of GlcAT-I expression.
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Affiliation(s)
- Lydia Barré
- UMR CNRS 7561-Université Henri Poincaré Nancy 1, Faculté de Médecine, BP 184, Vandoeuvre-lès-Nancy 54505, France
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93
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Abstract
The spectrum of all glycan structures--the glycome--is immense. In humans, its size is orders of magnitude greater than the number of proteins that are encoded by the genome, one percent of which encodes proteins that make, modify, localize or bind sugar chains, which are known as glycans. In the past decade, over 30 genetic diseases have been identified that alter glycan synthesis and structure, and ultimately the function of nearly all organ systems. Many of the causal mutations affect key biosynthetic enzymes, but more recent discoveries point to defects in chaperones and Golgi-trafficking complexes that impair several glycosylation pathways. As more glycosylation disorders and patients with these disorders are identified, the functions of the glycome are starting to be revealed.
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Affiliation(s)
- Hudson H Freeze
- Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, California 92037, USA.
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94
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Sparano A, Quesnelle KM, Kumar MS, Wang Y, Sylvester AJ, Feldman M, Sewell DA, Weinstein GS, Brose MS. Genome-Wide Profiling of Oral Squamous Cell Carcinoma by Array-Based Comparative Genomic Hybridization. Laryngoscope 2006; 116:735-41. [PMID: 16652080 DOI: 10.1097/01.mlg.0000205141.54471.7f] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Array-based comparative genomic hybridization (aCGH) was used to develop a genome-wide molecular profile of oral squamous cell carcinoma (OSCC). Copy number alterations (CNAs) were identified by chromosomal region, mapped to specific genes, and compared with several previously documented CNAs associated with head and neck squamous cell carcinoma (HNSCC). The status of 512 commonly altered cancer genes was assessed and evaluated as potential correlates of tumor behavior. METHODS Tumor tissue DNA was isolated for aCGH from 21 prospectively collected fresh-frozen OSCC specimens. aCGH was performed at 0.9-Mb resolution to identify distinct regions of genomic alteration and their associated genes. Cancer genes commonly altered were then correlated with clinicopathologic tumor data. RESULTS Genomic regions most frequently amplified (>35%) were located on 3q, 5p, 8q, 9q, and 20q, although regions most frequently deleted (>40%) involved chromosomes 3p, 8p, 13q, and 18q. Minimal regions of CNA identified, by aCGH narrowed larger, previously documented CNAs associated with HNSCC to significantly smaller regions, yielding shorter lists of candidate genes. Cancer-related genes altered in greater than 25% OSCC samples were identified (22 amplified, 17 deleted). Several genes associated with the Fanconi anemia DNA-damage response pathway were frequently altered, including BRCA1, BRCA2, FANCD2, and FANCG. Other cancer-related genes linked to hereditary cancer syndromes include VHL, MLH1, XPC, and RB1. CONCLUSIONS Genome-wide aCGH can be used to detect and map CNAs in OSCC tissue specimens with high resolution. These data implicate several candidate genes and gene pathways in the tumorigenesis of sporadic OSCC.
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Affiliation(s)
- Anthony Sparano
- Department of Otorhinolaryngology, Head and Neck, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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95
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Taylor KR, Gallo RL. Glycosaminoglycans and their proteoglycans: host‐associated molecular patterns for initiation and modulation of inflammation. FASEB J 2006; 20:9-22. [PMID: 16394262 DOI: 10.1096/fj.05-4682rev] [Citation(s) in RCA: 431] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Glycosaminoglycans, linear carbohydrates such as heparan sulfate and hyaluronan, participate in a variety of biological processes including cell-matrix interactions and activation of chemokines, enzymes and growth factors. This review will discuss progress in immunology and the science of wound repair that has revealed the importance of glycosaminoglycans, and their proteoglycans, in the inflammatory process. Heparan sulfate enables growth factor function and modifies enzyme/inhibitor functions, such as antithrombin III and heparin cofactor II. Heparan sulfate also interacts with cytokines/chemokines and participates in leukocyte selectin binding to promote the recruitment of leukocytes. Chondroitin sulfate/dermatan sulfate regulates growth factor activity and is an alternate modulator of heparin cofactor II. In addition, dermatan sulfate induces ICAM-1 expression on endothelial cells and also recruits leukocytes via selectin interactions. Hyaluronan alternatively participates in leukocyte recruitment via interaction with CD44, while activating various inflammatory cells, such as macrophages, through CD44-dependent signaling. Hyaluronan also signals through Toll-like receptor 4 to induce dendritic cell maturation and promote cytokine release by dendritic cells and endothelial cells. Taken together, the field of glycosaminoglycan biology provides new clues and explanations of the process of inflammation and suggests new therapeutic approaches to human disease.
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Affiliation(s)
- Kristen R Taylor
- Division of Dermatology, University of California, San Diego and VA Medical Center, San Diego, California, USA
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96
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Collins AE, Ferriero DM. The expanding spectrum of congenital disorders of glycosylation. J Pediatr 2005; 147:728-30. [PMID: 16356420 DOI: 10.1016/j.jpeds.2005.08.064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 08/23/2005] [Indexed: 11/20/2022]
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97
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Stickens D, Zak BM, Rougier N, Esko JD, Werb Z. Mice deficient in Ext2 lack heparan sulfate and develop exostoses. Development 2005; 132:5055-68. [PMID: 16236767 PMCID: PMC2767329 DOI: 10.1242/dev.02088] [Citation(s) in RCA: 192] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hereditary multiple exostoses (HME) is a genetically heterogeneous human disease characterized by the development of bony outgrowths near the ends of long bones. HME results from mutations in EXT1 and EXT2, genes that encode glycosyltransferases that synthesize heparan sulfate chains. To study the relationship of the disease to mutations in these genes, we generated Ext2-null mice by gene targeting. Homozygous mutant embryos developed normally until embryonic day 6.0, when they became growth arrested and failed to gastrulate, pointing to the early essential role for heparan sulfate in developing embryos. Heterozygotes had a normal lifespan and were fertile; however, analysis of their skeletons showed that about one-third of the animals formed one or more ectopic bone growths (exostoses). Significantly, all of the mice showed multiple abnormalities in cartilage differentiation, including disorganization of chondrocytes in long bones and premature hypertrophy in costochondral cartilage. These changes were not attributable to a defect in hedgehog signaling, suggesting that they arise from deficiencies in other heparan sulfate-dependent pathways. The finding that haploinsufficiency triggers abnormal cartilage differentiation gives insight into the complex molecular mechanisms underlying the development of exostoses.
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Affiliation(s)
- Dominique Stickens
- Department of Anatomy, University of California, San Francisco, CA 94143-0452, USA
| | - Beverly M. Zak
- Department of Cellular and Molecular Medicine, Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093-0687, USA
| | - Nathalie Rougier
- Department of Anatomy, University of California, San Francisco, CA 94143-0452, USA
| | - Jeffrey D. Esko
- Department of Cellular and Molecular Medicine, Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093-0687, USA
| | - Zena Werb
- Department of Anatomy, University of California, San Francisco, CA 94143-0452, USA
- Author for correspondence ()
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98
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Hecht JT, Hayes E, Haynes R, Cole WG, Long RJ, Farach-Carson MC, Carson DD. Differentiation-induced loss of heparan sulfate in human exostosis derived chondrocytes. Differentiation 2005; 73:212-21. [PMID: 16026543 DOI: 10.1111/j.1432-0436.2005.00025.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An exostosis or osteochondroma is an aberrant bony growth occurring next to the growth plate either as an isolated growth abnormality or as part of the Hereditary Multiple Exostosis (HME) syndrome. Mutations in either exostosin 1 (EXT1) or exostosin 2 (EXT2) gene cause the HME syndrome and also some isolated osteochondromas. The EXT1 and EXT2 genes are glycosyltransferases that function as hetero-oligomers in the Golgi to add repeating glycosaminoglycans (GAGs) to heparan sulfate (HS) chains. Previously, we demonstrated that HS is markedly diminished in the exostosis cartilage cap and that the HS proteoglycan, perlecan, has an abnormal distribution in these caps. The present studies were undertaken to evaluate which chondrocyte-specific functions are associated with diminished HS synthesis in human chondrocytes harboring either EXT1 or EXT2 mutations. Systematic evaluation of exostosis cartilage caps and chondrocytes, both in vitro and in vivo, suggests that chondrocyte-specific cell functions account for diminished HS levels. In addition, we provide evidence that perichondrial cells give rise to chondrocytes that clonally expand and develop into an exostosis. Undifferentiated EXT chondrocytes synthesized amounts of HS similar to control chondrocytes; however, EXT chondrocytes displayed very poor survival in vitro under conditions that promote normal chondrocyte differentiation with high efficiency. Collectively, these observations suggest that loss of one copy of either the EXT1 or EXT2 gene product compromises the perichondrial chondrocytes' ability to differentiate normally and to survive in a differentiated state in vitro. In vivo, these compromised responses may lead to abnormal chondrocyte growth, perhaps from a perichondrial stem cell reserve.
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Affiliation(s)
- Jacqueline T Hecht
- Department of Pediatrics, University of Texas-Houston Medical School, 6431 Fannin St. MSB 3.136, Houston, TX 77030, USA.
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99
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Norton WHJ, Ledin J, Grandel H, Neumann CJ. HSPG synthesis by zebrafish Ext2 and Extl3 is required for Fgf10 signalling during limb development. Development 2005; 132:4963-73. [PMID: 16221725 DOI: 10.1242/dev.02084] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Heparan sulphate proteoglycans (HSPGs) are known to be crucial for signalling by the secreted Wnt, Hedgehog, Bmp and Fgf proteins during invertebrate development. However, relatively little is known about their effect on developmental signalling in vertebrates. Here, we report the analysis of daedalus, a novel zebrafish pectoral fin mutant. Positional cloning identified fgf10 as the gene disrupted in daedalus. We find that fgf10 mutants strongly resemble zebrafish ext2 and extl3 mutants, which encode glycosyltransferases required for heparan sulphate biosynthesis. This suggests that HSPGs are crucial for Fgf10 signalling during limb development. Consistent with this proposal, we observe a strong genetic interaction between fgf10 and extl3 mutants. Furthermore, application of Fgf10 protein can rescue target gene activation in fgf10, but not in ext2 or extl3 mutants. By contrast, application of Fgf4 protein can activate target genes in both ext2 and extl3 mutants, indicating that ext2 and extl3 are differentially required for Fgf10, but not Fgf4, signalling during limb development. This reveals an unexpected specificity of HSPGs in regulating distinct vertebrate Fgfs.
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Affiliation(s)
- William H J Norton
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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100
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Affiliation(s)
- Erik A Eklund
- The Burnham Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
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