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Maiti G, Ashworth S, Choi T, Chakravarti S. Molecular cues for immune cells from small leucine-rich repeat proteoglycans in their extracellular matrix-associated and free forms. Matrix Biol 2023; 123:48-58. [PMID: 37793508 PMCID: PMC10841460 DOI: 10.1016/j.matbio.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/14/2023] [Accepted: 10/01/2023] [Indexed: 10/06/2023]
Abstract
In this review we highlight emerging immune regulatory functions of lumican, keratocan, fibromodulin, biglycan and decorin, which are members of the small leucine-rich proteoglycans (SLRP) of the extracellular matrix (ECM). These SLRPs have been studied extensively as collagen-fibril regulatory structural components of the skin, cornea, bone and cartilage in homeostasis. However, SLRPs released from a remodeling ECM, or synthesized by activated fibroblasts and immune cells contribute to an ECM-free pool in tissues and circulation, that may have a significant, but poorly understood foot print in inflammation and disease. Their molecular interactions and the signaling networks they influence also require investigations. Here we present studies on the leucine-rich repeat (LRR) motifs of SLRP core proteins, their evolutionary and functional relationships with other LRR pathogen recognition receptors, such as the toll-like receptors (TLRs) to bring some molecular clarity in the immune regulatory functions of SLRPs. We discuss molecular interactions of fragments and intact SLRPs, and how some of these interactions are likely modulated by glycosaminoglycan side chains. We integrate findings on molecular interactions of these SLRPs together with what is known about their presence in circulation and lymph nodes (LN), which are important sites of immune cell regulation. Recent bulk and single cell RNA sequencing studies have identified subsets of stromal reticular cells that express these SLRPs within LNs. An understanding of the cellular source, molecular interactions and signaling consequences will lead to a fundamental understanding of how SLRPs modulate immune responses, and to therapeutic tools based on these SLRPs in the future.
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Affiliation(s)
- George Maiti
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, United States
| | - Sean Ashworth
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, United States
| | - Tansol Choi
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, United States
| | - Shukti Chakravarti
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY, United States; Department of Pathology, NYU Grossman School of Medicine, New York, NY, United States.
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2
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Schwend T. Wiring the ocular surface: A focus on the comparative anatomy and molecular regulation of sensory innervation of the cornea. Differentiation 2023:S0301-4681(23)00010-5. [PMID: 36997455 DOI: 10.1016/j.diff.2023.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/23/2023] [Indexed: 01/29/2023]
Abstract
The cornea is richly innervated with sensory nerves that function to detect and clear harmful debris from the surface of the eye, promote growth and survival of the corneal epithelium and hasten wound healing following ocular disease or trauma. Given their importance to eye health, the neuroanatomy of the cornea has for many years been a source of intense investigation. Resultantly, complete nerve architecture maps exist for adult human and many animal models and these maps reveal few major differences across species. Interestingly, recent work has revealed considerable variation across species in how sensory nerves are acquired during developmental innervation of the cornea. Highlighting such species-distinct key differences, but also similarities, this review provides a full, comparative anatomy analysis of sensory innervation of the cornea for all species studied to date. Further, this article comprehensively describes the molecules that have been shown to guide and direct nerves toward, into and through developing corneal tissue as the final architectural pattern of the cornea's neuroanatomy is established. Such knowledge is useful for researchers and clinicians seeking to better understand the anatomical and molecular basis of corneal nerve pathologies and to hasten neuro-regeneration following infection, trauma or surgery that damage the ocular surface and its corneal nerves.
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Miller MC, Cai C, Wichapong K, Bhaduri S, Pohl NLB, Linhardt RJ, Gabius HJ, Mayo KH. Structural insight into the binding of human galectins to corneal keratan sulfate, its desulfated form and related saccharides. Sci Rep 2020; 10:15708. [PMID: 32973213 PMCID: PMC7515912 DOI: 10.1038/s41598-020-72645-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/11/2020] [Indexed: 02/08/2023] Open
Abstract
Glycosaminoglycan chains of keratan sulfate proteoglycans appear to be physiologically significant by pairing with tissue lectins. Here, we used NMR spectroscopy and molecular dynamics (MD) simulations to characterize interactions of corneal keratan sulfate (KS), its desulfated form, as well as di-, tetra- (N-acetyllactosamine and lacto-N-tetraose) and octasaccharides with adhesion/growth-regulatory galectins, in particular galectin-3 (Gal-3). The KS contact region involves the lectin canonical binding site, with estimated KD values in the low µM range and stoichiometry of ~ 8 to ~ 20 galectin molecules binding per polysaccharide chain. Compared to Gal-3, the affinity to Gal-7 is relatively low, signaling preferences among galectins. The importance of the sulfate groups was delineated by using desulfated analogs that exhibit relatively reduced affinity. Binding studies with two related di- and tetrasaccharides revealed a similar decrease that underscores affinity enhancement by repetitive arrangement of disaccharide units. MD-based binding energies of KS oligosaccharide-loaded galectins support experimental data on Gal-3 and -7, and extend the scope of KS binding to Gal-1 and -9N. Overall, our results provide strong incentive to further probe the relevance of molecular recognition of KS by galectins in terms of physiological processes in situ, e.g. maintaining integrity of mucosal barriers, intermolecular (lattice-like) gluing within the extracellular meshwork or synaptogenesis.
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Affiliation(s)
- Michelle C Miller
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Chao Cai
- Biocatalysis and Metabolic Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Kanin Wichapong
- Department of Biochemistry and the Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Sayantan Bhaduri
- Department of Chemistry, Indiana University, Bloomington, IN, 47405, USA
| | - Nicola L B Pohl
- Department of Chemistry, Indiana University, Bloomington, IN, 47405, USA
| | - Robert J Linhardt
- Biocatalysis and Metabolic Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Hans-Joachim Gabius
- Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximillians-University Munich, 80539, Munich, Germany
| | - Kevin H Mayo
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
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4
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Hao R, Zheng Z, Wang Q, Du X, Deng Y, Huang R. Molecular and functional analysis of PmCHST1b in nacre formation of Pinctada fucata martensii. Comp Biochem Physiol B Biochem Mol Biol 2018; 225:13-20. [PMID: 29981452 DOI: 10.1016/j.cbpb.2018.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 06/27/2018] [Accepted: 06/27/2018] [Indexed: 11/27/2022]
Abstract
Keratan sulfate possesses considerable amounts of negatively charged sulfonic acid groups and participates in biomineralization. In the present study, we investigated characteristics and functions of a CHST1 gene identified from the pearl oyster Pinctada fucata martensii (PmCHST1b) which participated in the synthesis of keratan sulfate. PmCHST1b amino acid sequence carried a typical sulfotransferase-3 domain (sulfotransfer-3 domain) and belonged to membrane-associated sulfotransferases. Homologous analysis of CHST1 from different species showed the conserved motif (5' PSB motif and 3' PB motif) which interacted with 3'-phosphoadenosine-5'-phosphosulfate (PAPS). Structure analysis of sulfotransferase domain indicted that PmCHST1b showed the conserved catalytic structure character and the relationships presented in the phylogenetic tree conformed to that of traditional taxonomy. Expression pattern of PmCHST1b in different tissues and development stages showed that PmCHST1b widely expressed in all the detected tissues and development stages and showed the highest expression level in the central zone of mantle (MC). PmCHST1b expressed highly in the trochophore, D-stage larvae and spat which corresponded to prodissoconch and dissoconch shell formation, respectively. RNA interference (RNAi) successfully inhibited expression level of PmCHST1b in MC (P<0.05), and sulfate polymer content in the extrapallial fluid significantly reduced (P<0.05). Crystallization of shell nacre became irregular. Results above indicated that PmCHST1b may affect nacre formation by participating in synthesis of keratan sulfate in extrapallial fluid. This study provided fundamental materials for further research on the role of sulfotransferases and keratan sulfate in nacre formation.
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Affiliation(s)
- Ruijuan Hao
- Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Zhe Zheng
- Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Qingheng Wang
- Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China; Pearl Breeding and Processing Engineering Technology Research Centre of Guangdong Province, Zhanjiang 524088, China.
| | - Xiaodong Du
- Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China; Pearl Breeding and Processing Engineering Technology Research Centre of Guangdong Province, Zhanjiang 524088, China.
| | - Yuewen Deng
- Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China; Pearl Breeding and Processing Engineering Technology Research Centre of Guangdong Province, Zhanjiang 524088, China
| | - Ronglian Huang
- Fisheries College, Guangdong Ocean University, Zhanjiang, 524088, China; Pearl Breeding and Processing Engineering Technology Research Centre of Guangdong Province, Zhanjiang 524088, China
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Caterson B, Melrose J. Keratan sulfate, a complex glycosaminoglycan with unique functional capability. Glycobiology 2018; 28:182-206. [PMID: 29340594 PMCID: PMC5993099 DOI: 10.1093/glycob/cwy003] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Revised: 12/20/2017] [Accepted: 01/08/2018] [Indexed: 12/19/2022] Open
Abstract
From an evolutionary perspective keratan sulfate (KS) is the newest glycosaminoglycan (GAG) but the least understood. KS is a sophisticated molecule with a diverse structure, and unique functional roles continue to be uncovered for this GAG. The cornea is the richest tissue source of KS in the human body but the central and peripheral nervous systems also contain significant levels of KS and a diverse range of KS-proteoglycans with essential functional roles. KS also displays important cell regulatory properties in epithelial and mesenchymal tissues and in bone and in tumor development of diagnostic and prognostic utility. Corneal KS-I displays variable degrees of sulfation along the KS chain ranging from non-sulfated polylactosamine, mono-sulfated and disulfated disaccharide regions. Skeletal KS-II is almost completely sulfated consisting of disulfated disaccharides interrupted by occasional mono-sulfated N-acetyllactosamine residues. KS-III also contains highly sulfated KS disaccharides but differs from KS-I and KS-II through 2-O-mannose linkage to serine or threonine core protein residues on proteoglycans such as phosphacan and abakan in brain tissue. Historically, the major emphasis on the biology of KS has focused on its sulfated regions for good reason. The sulfation motifs on KS convey important molecular recognition information and direct cell behavior through a number of interactive proteins. Emerging evidence also suggest functional roles for the poly-N-acetyllactosamine regions of KS requiring further investigation. Thus further research is warranted to better understand the complexities of KS.
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Affiliation(s)
- Bruce Caterson
- Connective Tissue Biology Laboratories, School of Biosciences, College of Biological & Life Sciences, Cardiff University, Cardiff, Wales, UK
| | - James Melrose
- Raymond Purves Bone and Joint Research Laboratory, Kolling Institute of Medical Research, Northern Sydney Local Health District, St. Leonards, NSW, Australia
- Sydney Medical School, Northern, The University of Sydney, Royal North Shore Hospital, St. Leonards, NSW, Australia
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
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6
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Corneal Development: Different Cells from a Common Progenitor. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:43-59. [PMID: 26310148 DOI: 10.1016/bs.pmbts.2015.04.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Development of the vertebrate cornea is a multistep process that involves cellular interactions between various ectodermal-derived tissues. Bilateral interactions between the neural ectoderm-derived optic vesicles and the cranial ectoderm give rise to the presumptive corneal epithelium and other epithelia of the ocular surface. Interactions between the neural tube and the adjacent ectoderm give rise to the neural crest cells, a highly migratory and multipotent cell population. Neural crest cells migrate between the lens and presumptive corneal epithelium to form the corneal endothelium and the stromal keratocytes. The sensory nerves that abundantly innervate the corneal stroma and epithelium originate from the neural crest- and ectodermal placode-derived trigeminal ganglion. Concomitant with corneal innervation is the formation of the limbal vascular plexus and the establishment of corneal avascularity. This review summarizes historical and current research to provide an overview of the genesis of the cellular layers of the cornea, corneal innervation, and avascularity.
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7
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Nairn AV, Aoki K, dela Rosa M, Porterfield M, Lim JM, Kulik M, Pierce JM, Wells L, Dalton S, Tiemeyer M, Moremen KW. Regulation of glycan structures in murine embryonic stem cells: combined transcript profiling of glycan-related genes and glycan structural analysis. J Biol Chem 2012; 287:37835-56. [PMID: 22988249 DOI: 10.1074/jbc.m112.405233] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The abundance and structural diversity of glycans on glycoproteins and glycolipids are highly regulated and play important roles during vertebrate development. Because of the challenges associated with studying glycan regulation in vertebrate embryos, we have chosen to study mouse embryonic stem (ES) cells as they differentiate into embryoid bodies (EBs) or into extraembryonic endodermal (ExE) cells as a model for cellular differentiation. We profiled N- and O-glycan structures isolated from these cell populations and examined transcripts encoding the corresponding enzymatic machinery for glycan biosynthesis in an effort to probe the mechanisms that drive the regulation of glycan diversity. During differentiation from mouse ES cells to either EBs or ExE cells, general trends were detected. The predominance of high mannose N-glycans in ES cells shifted to an equal abundance of complex and high mannose structures, increased sialylation, and increased α-Gal termination in the differentiated cell populations. Whereas core 1 O-glycan structures predominated in all three cell populations, increased sialylation and increased core diversity characterized the O-glycans of both differentiated cell types. Increased polysialylation was also found in both differentiated cell types. Differences between the two differentiated cell types included greater sialylation of N-glycans in EBs, whereas α-Gal-capped structures were more prevalent in ExE cells. Changes in glycan structures generally, but not uniformly, correlated with alterations in transcript abundance for the corresponding biosynthetic enzymes, suggesting that transcriptional regulation contributes significantly to the regulation of glycan expression. Knowledge of glycan structural diversity and transcript regulation should provide greater understanding of the roles of protein glycosylation in vertebrate development.
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Affiliation(s)
- Alison V Nairn
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, USA
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8
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Koudouna E, Veronesi G, Patel II, Cotte M, Knupp C, Martin FL, Quantock AJ. Chemical composition and sulfur speciation in bulk tissue by x-ray spectroscopy and x-ray microscopy: corneal development during embryogenesis. Biophys J 2012; 103:357-64. [PMID: 22853914 DOI: 10.1016/j.bpj.2012.05.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 04/30/2012] [Accepted: 05/02/2012] [Indexed: 10/28/2022] Open
Abstract
The chemical composition and sulfur (S) speciation of developing chick corneas at embryonic days 12, 14, and 16 were investigated using synchrotron scanning x-ray fluorescence microscopy and x-ray absorption near-edge structure spectroscopy. The aim was to develop techniques for the analysis of bulk tissue and identify critical physicochemical variations that correlate with changes in corneal structure-function relationships. Derived data were subjected to principal component analysis and linear discriminant analysis, which highlighted differences in the elemental and S species composition at different stages of embryonic growth. Notably, distinct elemental compositions of chlorine, potassium, calcium, phosphorus, and S altered with development during the transition of the immature opaque cornea to a mature transparent tissue. S structure spectroscopy revealed developmentally regulated alterations in thiols, organic monosulfides, ester sulfate, and inorganic sulfate species. The transient molecular structures and compositional changes reported here provide a deeper understanding of the underlying basis of corneal development during the acquisition of transparency. The experimental and analytical approach is new, to our knowledge, and has wide potential applicability in the life sciences.
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Affiliation(s)
- Elena Koudouna
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Wales, United Kingdom
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9
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Dellett M, Hu W, Papadaki V, Ohnuma SI. Small leucine rich proteoglycan family regulates multiple signalling pathways in neural development and maintenance. Dev Growth Differ 2012; 54:327-40. [DOI: 10.1111/j.1440-169x.2012.01339.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Margaret Dellett
- University College London (UCL) Institute of Ophthalmology; UCL; London; UK
| | - Wanzhou Hu
- University College London (UCL) Institute of Ophthalmology; UCL; London; UK
| | - Vasiliki Papadaki
- University College London (UCL) Institute of Ophthalmology; UCL; London; UK
| | - Shin-ichi Ohnuma
- University College London (UCL) Institute of Ophthalmology; UCL; London; UK
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10
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Ko JA, Chikama TI, Sonoda KH, Kiuchi Y. Up-regulation of matrix metalloproteinase-1 and interleukin-6 expression in cocultures of corneal fibroblasts and neural cells. Biochem Biophys Res Commun 2012; 419:537-42. [DOI: 10.1016/j.bbrc.2012.02.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 02/10/2012] [Indexed: 10/28/2022]
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Quantock AJ, Young RD, Akama TO. Structural and biochemical aspects of keratan sulphate in the cornea. Cell Mol Life Sci 2010; 67:891-906. [PMID: 20213925 PMCID: PMC11115788 DOI: 10.1007/s00018-009-0228-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 12/02/2009] [Accepted: 12/04/2009] [Indexed: 12/13/2022]
Abstract
Keratan sulphate (KS) is the predominant glycosaminoglycan (GAG) in the cornea of the eye, where it exists in proteoglycan (PG) form. KS-PGs have long been thought to play a pivotal role in the establishment and maintenance of the array of regularly-spaced and uniformly- thin collagen fibrils which make up the corneal stroma. This characteristic arrangement of fibrils allows light to pass through the cornea. Indeed, perturbations to the synthesis of KS-PG core proteins in genetically altered mice lead to structural matrix alterations and corneal opacification. Similarly, mutations in enzymes responsible for the sulphation of KS-GAG chains are causative for the inherited human disease, macular corneal dystrophy, which is manifested clinically by progressive corneal cloudiness starting in young adulthood.
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Quantock AJ, Young RD. Development of the corneal stroma, and the collagen-proteoglycan associations that help define its structure and function. Dev Dyn 2008; 237:2607-21. [PMID: 18521942 DOI: 10.1002/dvdy.21579] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The cornea of the eye is a unique, transparent connective tissue. It is comprised predominantly of collagen fibrils, remarkably uniform in diameter and regularly spaced, organized into an intricate lamellar array. Its establishment involves a precisely controlled sequence of developmental events in which the embryonic cornea undergoes major structural transformations that ultimately determine tissue form and function. In this article, we will review corneal developmental dynamics from a structural perspective, consider the roles and interrelationships of collagens and proteoglycans, and comment on contemporary concepts and current challenges pertinent to developmental processes that result in an optically clear, mature cornea.
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Affiliation(s)
- Andrew J Quantock
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Wales, United Kingdom.
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13
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Gealy EC, Kerr BC, Young RD, Tudor D, Hayes AJ, Hughes CE, Caterson B, Quantock AJ, Ralphs JR. Differential expression of the keratan sulphate proteoglycan, keratocan, during chick corneal embryogenesis. Histochem Cell Biol 2007; 128:551-5. [PMID: 17851677 DOI: 10.1007/s00418-007-0332-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2007] [Indexed: 10/22/2022]
Abstract
Keratan sulphate (KS) proteoglycans (PGs) are key molecules in the connective tissue matrix of the cornea of the eye, where they are believed to have functional roles in tissue organisation and transparency. Keratocan, is one of the three KS PGs expressed in cornea, and is the only one that is primarily cornea-specific. Work with the developing chick has shown that mRNA for keratocan is present in early corneal embryogenesis, but there is no evidence of protein synthesis and matrix deposition. Here, we investigate the tissue distribution of keratocan in the developing chick cornea as it becomes compacted and transparent in the later stages of development. Indirect immunofluorescence using a new monoclonal antibody (KER-1) which recognises a protein epitope on the keratocan core protein demonstrated that keratocan was present at all stages investigated (E10-E18), with distinct differences in localisation and organisation observed between early and later stages. Until E13, keratocan appeared both cell-associated and in the stromal extracellular matrix, and was particularly concentrated in superficial tissue regions. By E14 when the cornea begins to become transparent, keratocan was located in elongate arrays, presumably associated along collagen fibrils in the stroma. This fibrillar label was still concentrated in the anterior stroma, and persisted through E15-E18. Presumptive Bowman's layer was evident as an unlabelled subepithelial zone at all stages. Thus, in embryonic chick cornea, keratocan, in common with sulphated KS chains in the E12-E14 developmental period, exhibits a preferential distribution in the anterior stroma. It undergoes a striking reorganisation of structure and distribution consistent with a role in relation to stromal compaction and corneal transparency.
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Affiliation(s)
- E Claire Gealy
- Connective Tissue Biology Laboratories, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3US, Wales, UK
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Oguma T, Tomatsu S, Okazaki O. Analytical method for determination of disaccharides derived from keratan sulfates in human serum and plasma by high-performance liquid chromatography/turbo-ionspray ionization tandem mass spectrometry. Biomed Chromatogr 2007; 21:356-62. [PMID: 17236248 DOI: 10.1002/bmc.760] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We established a highly sensitive LC/MS/MS method for the analysis of the disaccharides produced from keratan sulfates (KS). It was revealed that the disaccharides produced by keratanase II enzymatic digestion of KS could be determined with high sensitivity by negative ion mode of multiple reaction monitoring. Furthermore, monosulfated and disulfated disaccharides can be separated using a Hypercarb (2.0 mm i.d. x 150 mm, 5 microm) with a gradient elution of acetonitrile-0.01 m ammonium bicarbonate (pH 10). This method was applied to the determination of KS in serum and plasma of control subjects. The intra-day precision expressed as %CV was within 6.8% for five replicate analyses with three different control serum. The inter-day (overall, n = 15) precision was within 7.3% for three days. This method is sensitive, reproducible and would be useful for clinical analysis.
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Affiliation(s)
- Toshihiro Oguma
- Drug Metabolism and Physicochemistry Research Laboratory, Daiichi Pharmaceutical Co. Ltd, 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan.
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15
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Lwigale PY, Cressy PA, Bronner-Fraser M. Corneal keratocytes retain neural crest progenitor cell properties. Dev Biol 2005; 288:284-93. [PMID: 16263107 DOI: 10.1016/j.ydbio.2005.09.046] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 09/27/2005] [Accepted: 09/30/2005] [Indexed: 11/25/2022]
Abstract
Corneal keratocytes have a remarkable ability to heal the cornea throughout life. Given their developmental origin from the cranial neural crest, we asked whether this regenerative ability was related to the stem cell-like properties of their neural crest precursors. To this end, we challenged corneal stromal keratocytes by injecting them into a new environment along cranial neural crest migratory pathways. The results show that injected stromal keratocytes change their phenotype, proliferate and migrate ventrally adjacent to host neural crest cells. They then contribute to the corneal endothelial and stromal layers, the musculature of the eye, mandibular process, blood vessels and cardiac cushion tissue of the host. However, they fail to form neurons in cranial ganglia or branchial arch cartilage, illustrating that they are at least partially restricted progenitors rather than stem cells. The data show that, even at late embryonic stages, corneal keratocytes are not terminally differentiated, but maintain plasticity and multipotentiality, contributing to non-neuronal cranial neural crest derivatives.
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16
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Connon CJ, Meek KM, Kinoshita S, Quantock AJ. Spatial and temporal alterations in the collagen fibrillar array during the onset of transparency in the avian cornea. Exp Eye Res 2004; 78:909-15. [PMID: 15051472 DOI: 10.1016/j.exer.2004.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2003] [Accepted: 01/20/2004] [Indexed: 11/15/2022]
Abstract
In the latter stages of development, the embryonic avian cornea undergoes significant changes in structure, composition and transparency. The rearrangement of stromal collagen fibrils at this time is important because it is believed to play a key role in the acquisition of corneal transparency. Here, we investigate spatial alterations in the internal fine structure of the avian cornea during development. Chicken corneas at developmental days 14, 16 and 18 were examined by transmission electron microscopy and quantitative image analysis. For anterior and posterior regions we determined fibril number densities, two-dimensional distribution functions, and, where appropriate, radial distribution functions. Stromal collagen fibrils became more closely spaced over the developmental range studied here. Changes in fibril number density indicated that fibrils became compacted first in the anterior stroma, and later (i.e. after day 16) in the posterior stroma. By day 18 collagen fibril number densities were essentially the same in superficial and deep tissue regions. At day 14, two-dimensional distribution functions of collagen fibrils in the posterior stroma pointed to a fibrillar array that was unlike that in the anterior stroma because there was no clear radial symmetry. Rather, in the deep stroma at day 14 there was evidence of different nearest neighbour spacings in two orthogonal directions. By day 18, fibril distributions in the anterior and posterior stroma were spatially homogeneous and radially symmetric, with radial distribution functions typical of those ordinarily found in mature cornea. Corneal transparency requires the stromal matrix to have some degree of regularity in the arrangement of its uniformly thin collagen fibrils. The chicken cornea becomes progressively transparent between days 14 and 18 of development as the stroma dehydrates and thins. We show that over this time period collagen fibrils in the anterior stroma become configured in advance of fibrils in deeper stromal regions, leading to questions over the potential roles of sulphated proteoglycans in different regions of the corneal stroma during morphogenesis.
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Affiliation(s)
- Che J Connon
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Akama TO, Misra AK, Hindsgaul O, Fukuda MN. Enzymatic synthesis in vitro of the disulfated disaccharide unit of corneal keratan sulfate. J Biol Chem 2002; 277:42505-13. [PMID: 12218059 DOI: 10.1074/jbc.m207412200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Among the enzymes of the carbohydrate sulfotransferase family, human corneal GlcNAc 6-O-sulfotransferase (hCGn6ST, also known as human GlcNAc6ST-5/GST4beta) and human intestinal GlcNAc 6-O-sulfotransferase (hIGn6ST or human GlcNAc6ST-3/GST4alpha) are highly homologous. In the mouse, intestinal GlcNAc 6-O-sulfotransferase (mIGn6ST or mouse GlcNAc6ST-3/GST4) is the only orthologue of hCGn6ST and hIGn6ST. In the previous study, we found that hCGn6ST and mIGn6ST, but not hIGn6ST, have sulfotransferase activity to produce keratan sulfate (Akama, T. O., Nakayama, J., Nishida, K., Hiraoka, N., Suzuki, M., McAuliffe, J., Hindsgaul, O., Fukuda, M., and Fukuda, M. N. (2001) J. Biol. Chem. 276, 16271-16278). In this study, we analyzed the substrate specificities of these sulfotransferases in vitro using synthetic carbohydrate substrates. We found that all three sulfotransferases can transfer sulfate to the nonreducing terminal GlcNAc of short carbohydrate substrates. Both hCGn6ST and mIGn6ST, but not hIGn6ST, transfer sulfate to longer carbohydrate substrates that have poly-N-acetyllactosamine structures, suggesting the involvement of hCGn6ST and mIGn6ST in production of keratan sulfate. To clarify further the involvement of hCGn6ST in biosynthesis of keratan sulfate, we reconstituted the biosynthetic pathway in vitro by sequential enzymatic treatment of a synthetic carbohydrate substrate. Using four enzymes, beta1,4-galactosyltransferase-I, beta1,3-N-acetylglucosaminyltransferase-2, hCGn6ST, and keratan sulfate Gal 6-O-sulfotransferase, we were able to synthesize in vitro a product that conformed to the basic structural unit of keratan sulfate. Based on these results, we propose a biosynthetic pathway for N-linked keratan sulfate on corneal proteoglycans.
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Affiliation(s)
- Tomoya O Akama
- Glycobiology Program, The Burnham Institute, La Jolla, California 92037, USA.
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Ogata N, Takahashi I, Nakazawa K. Purification and characterization of chick corneal beta-D-glucuronyltransferase involved in chondroitin sulfate biosynthesis. Biol Pharm Bull 2002; 25:1282-8. [PMID: 12392079 DOI: 10.1248/bpb.25.1282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Beta-D-Glucuronyltransferase, which transfers D-glucuronic acid (GlcA) from UDP-GlcA to N-acetyl-D-galactosamine (GalNAc) at the nonreducing end of chondro-pentasaccharide-PA (pyridylamino-), GalNAcbeta1-(4GlcAbeta1-3GalNAcbeta1)2-PA, was purified 339-fold with an 11.0% yield from 2-d-old chick corneas by chromatography on DEAE-Sepharose, WGA-agarose, heparin-Sepharose, and 1st and 2nd UDP-GlcA-agarose (in the presence of Gal) columns. The activity was detected by fluorescence of PA residues of the product. The purified enzyme has an optimum pH of 7.0 (Mes buffer), and much higher activity toward chondro-heptasaccharide-PA than toward the chondro-pentasaccharide-PA, but no activity toward p-nitrophenyl-beta-GalNAc. The enzyme activity was almost completely inhibited by GalNAc (20 mm). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the purified enzyme fraction showed one band of 38 kDa with many other bands. The amino acid sequence was determined for the tryptic digests of the 38 kDa band protein. The sequences determined showed no homology to those of several beta-glucuronyltransferases reported previously. It seems that the enzyme is involved in the elongation of chondroitin sulfate chains in vivo.
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Affiliation(s)
- Nana Ogata
- Section of Radiochemistry, Meijo University, Nagoya, Japan
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19
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Abstract
The detection of microquantities of glycosaminoglycans (GAGs) in biological samples has been hampered by the lack of sensitive methods. In this paper we describe the modification and development of three sensitive assays capable of detecting nanogram quantities of GAGs in biological samples. The first assay detects total GAGs. It is a modified Alcian blue dye precipitation assay in which the dye binds to the negatively charged GAGs in CsCl-fractionated extracts from chicken tendons. This assay compares favorably with the widely used uronic acid assay in terms of its sensitivity and ability to detect all classes of GAGs, including keratan sulfate (KS). Two other assays, dot-blotting and immunoblotting, detect KS in complex mixtures and can be easily adapted for the detection of other GAGs. Both take advantage of binding of carboxyl and sulfate groups of GAGs to trivalent neodymium. In dot-blotting, samples were directly blotted onto nitrocellulose membrane soaked in Nd(2)(SO(4))(3) buffer, and KS was detected with the monoclonal anti-KS 5-D-4 antibody and an avidin-biotin complex detection system. In immunoblotting, the samples were first separated in 28% polyacrylamide gels, transferred onto a Nd(2)(SO(4))(3)-soaked nitrocellulose membrane using a phosphate buffer system, and stained and developed using the same protocol as in dot-blotting. Whereas dot-blotting allows the use of very low quantities of samples because of its high sensitivity (lower detection limit was 5 ng), immunoblotting provides more specificity.
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Affiliation(s)
- Jung Hae Yoon
- The Soft Tissue Center, Department of Pathology, College of Veterinary Medicine, The University of Georgia, Athens 30602, USA.
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Oguma T, Toyoda H, Toida T, Imanari T. Analytical method for keratan sulfates by high-performance liquid chromatography/turbo-ionspray tandem mass spectrometry. Anal Biochem 2001; 290:68-73. [PMID: 11180938 DOI: 10.1006/abio.2000.4940] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We established a highly sensitive LC/MS/MS method for the analysis of the disaccharides produced from keratan sulfates (KS). It was revealed that the disaccharides produced by keratanase II enzymatic digestion of KS could be determined with high sensitivity by the negative-ion mode of multiple reaction monitoring. Furthermore, monosulfated and disulfated disaccharides can be separated using a short column of Capcell Pak NH2 UG80 (35 mm x 2 mm i.d.). The complete analysis of one sample can be performed within 5 min. The assay method was validated and showed satisfactory sensitivity, precision, and accuracy, which enabled quantitation at subpicomole levels. From the results of analyses of KS obtained from cornea, nasal cartilage, and brain, it was found that the degree of sulfation at the C-6 position of the galactose residues differed among those samples in the following order: nasal cartilage > cornea > brain. Our analytical method is very useful for the analyses of KS in various biological materials and for comparison of the degree of sulfation of KS from various biological samples.
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Affiliation(s)
- T Oguma
- Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi, Inage, Chiba, 263-8522,
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21
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Corpuz LM, Dunlevy JR, Hassell JR, Conrad AH, Conrad GW. Molecular cloning and relative tissue expression of keratocan and mimecan in embryonic quail cornea. Matrix Biol 2000; 19:693-8. [PMID: 11102758 DOI: 10.1016/s0945-053x(00)00116-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have cloned and sequenced the cDNAs for quail cornea keratan sulfate proteoglycan core proteins, keratocan and mimecan. The deduced quail keratocan protein contains a single conservative amino acid difference from the chick sequence, whereas quail mimecan protein contains a 58 amino acid-long avian-unique sequence that shares no homology with mammalian mimecan. Ribonuclease protection assay of Day 16 embryonic quail tissues reveals that keratocan and lumican are expressed at highest levels in cornea, whereas mimecan mRNA is expressed at a much lower level. Keratocan is expressed only in quail cornea, whereas mimecan is expressed in many different tissues as four transcripts of different sizes. Both lumican and mimecan are expressed at lowest levels in brain, liver and sternum.
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Affiliation(s)
- L M Corpuz
- Division of Biology, Kansas State University, Manhattan, KS 66506-4901, USA
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22
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Sundarraj N, Fite D, Belak R, Sundarraj S, Rada J, Okamoto S, Hassell J. Proteoglycan distribution during healing of corneal stromal wounds in chick. Exp Eye Res 1998; 67:433-42. [PMID: 9820791 DOI: 10.1006/exer.1998.0540] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Proteoglycan distribution during corneal stromal healing in growing corneas of young chicks were histologically and immunohistochemically analysed. Single linear incisions to produce partial-thickness wounds were made in the corneas of 5 day old chicks. The corneas were harvested at different times after wounding and processed for either histochemical analyses using periodic acid-Schiff's reaction (PAS) or for indirect immunofluorescence analyses of lumican, keratocan, keratan sulfate, perlecan and laminin. Linear corneal stromal incisions were completely covered by migrated stratified epithelium by day 2 post wounding and resulted in a gaping wound with a thinner stroma. New stromal scar tissue formed between the epithelium and the original stroma that resulted in partial restoration of stromal thickness. During the first two to three weeks of healing, the stromal tissue filling the depression formed from the gaping wound, was hypercellular and PAS positive, indicating significantly higher levels of glycoprotein content but no new Bowman's membrane was formed. By four weeks, the scar tissue occupied a 2-3 mm wide region. Immunofluorescence analyses indicated that other major differences in the healing and normally growing stroma were the increased synthesis and deposition of perlecan and laminin. No differences were evident in the immunofluorescence for keratocan or keratan sulfate in the scar tissue, but the scar tissue did contain markedly decreased levels of lumican. Thus, the regulation of proteoglycan and glycoprotein synthesis is altered in the keratocytes that are recruited to the wounded regions in the growing corneal stroma of post-hatched young chicks. While synthesis and deposition of adhesive molecules including laminin and perlecan are elevated, the synthesis of one of the keratan sulfate proteoglycans, lumican, is reduced in the scar tissue as compared to the normally growing stroma.
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Affiliation(s)
- N Sundarraj
- University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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23
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Hassell JR, Rada J, Cornuet P, Vergnes JP, Kinchington PR. Gene structure of chick lumican and identification of the first exon. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1397:119-25. [PMID: 9565663 DOI: 10.1016/s0167-4781(98)00022-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Three overlapping genomic clones to chick lumican were isolated and then characterized using restriction enzyme analyses, Southern blot analyses with cDNA probes, and by DNA sequencing. The results showed chick lumican gene to consist of 3 exons with a 2.9-kb first intron and a 4.2-kb second intron. Transcription initiation sites, identified by S1 nuclease experiments using genomic fragments containing exon 1 and by primer extension analysis of RNA, indicated the first exon to be 303 b. Two TATA sequences were 31 and 49 bases upstream of the first exon. The first exon contained all 5' untranslated sequence. The second exon was 896 b and contains 20 b of untranslated sequence, and codes for the start methionine to the end of the 10th leucine rich repeat. The third exon is 880 b and codes for the remainder of the core protein, and 724 b of untranslated 3' sequence. A 1-kb genomic fragment containing a portion of exon 1 and upstream sequence in a luciferase reporter sector showed specific promotor activity in the forward, but not the reverse direction when transfected into corneal fibroblasts. These results show the chick lumican gene to consist of three exons, and that regulatory elements are present within 1 kb upstream of the first exon.
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Affiliation(s)
- J R Hassell
- Shriners Hospitals for Children-Tampa, 12502 North Pine Drive, Tampa, FL 33612, USA
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24
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Fukuta M, Inazawa J, Torii T, Tsuzuki K, Shimada E, Habuchi O. Molecular cloning and characterization of human keratan sulfate Gal-6-sulfotransferase. J Biol Chem 1997; 272:32321-8. [PMID: 9405439 DOI: 10.1074/jbc.272.51.32321] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We have previously cloned chondroitin 6-sulfotransferase (C6ST) cDNA from chick embryo chondrocytes. C6ST catalyzes sulfation of chondroitin, keratan sulfate, and sialyl N-acetyllactosamine oligosaccharides. In this study, we report the cloning and characterization of a novel sulfotransferase that catalyzes sulfation of keratan sulfate. This new sulfotransferase cDNA clone was obtained from a human fetal brain library by cross-hybridization with chick C6ST cDNA. The cDNA clone obtained contains a single open reading frame that predicts a type II transmembrane protein composed of 411 amino acid residues. When the cDNA was introduced into a eukaryotic expression vector and transfected in COS-7 cells, keratan sulfate sulfotransferase activity was overexpressed, but C6ST activity was not increased over that of the control. Structural analysis of 35S-labeled glycosaminoglycan, which was formed from keratan sulfate by the reaction with 35S-labeled 3'-phosphoadenosine 5'-phosphosulfate and the recombinant sulfotransferase, showed that keratan sulfate was sulfated at position 6 of Gal residues. On the basis of the acceptor substrate specificity, we propose keratan sulfate Gal-6-sulfotransferase (KSGal6ST) for the name of the newly cloned sulfotransferase. KSGal6ST was assigned to chromosome 11p11. 1-11.2 by fluorescence in situ hybridization. Among various human adult tissues, a 2.8-kilobase message of KSGal6ST was expressed mainly in the brain. When poly(A)+ RNAs from the chick embryo cornea and brain were probed with the human KSGal6ST cDNA in Northern hybridization, a clear band with about 2.8 kilobases was detected. These observations suggest that KSGal6ST may participate in the biosynthesis of keratan sulfate in the brain and cornea.
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Affiliation(s)
- M Fukuta
- Department of Life Science, Aichi University of Education, Kariya, Aichi 448, Japan
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25
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Ying S, Shiraishi A, Kao CW, Converse RL, Funderburgh JL, Swiergiel J, Roth MR, Conrad GW, Kao WW. Characterization and expression of the mouse lumican gene. J Biol Chem 1997; 272:30306-13. [PMID: 9374517 DOI: 10.1074/jbc.272.48.30306] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Lumican is one of the major keratan sulfate proteoglycans (KSPG) in vertebrate corneas. We previously cloned the murine lumican cDNA. This study determines the structure of murine lumican gene (Lum) and its expression during mouse embryonic developments. The mouse lumican gene was isolated from a bacterial artificial chromosome mouse genomic DNA library and characterized by polymerase chain reaction and Southern hybridization. The lumican gene spans 6.9 kilobase pairs of mouse genome. The gene consists of three exons and two introns. Exon 1 constitutes 88 bases (b) of untranslated sequence. Exon 2 is 883 b and contains most of the coding sequence of lumican mRNA, and exon 3 has 152 b of coding sequence and 659 b of 3' noncoding sequence. The mouse lumican gene has a TATCA element, a presumptive TATA box, which locates 27 b 5'-upstream from the transcription initiation site. Northern hybridization and in situ hybridization indicate that in early stages of embryonic development, day 7 post coitus the embryo expresses little or no lumican. Thereafter, different levels of lumican mRNA can be detected in various organ systems, such as cornea stroma, dermis, cartilage, heart, lung, and kidney. The cornea and heart are the two tissues that have the highest expression in adult. Immunoblotting studies found that KSPG core proteins became abundant in the cornea and sclera by postnatal day 10 but that sulfated KSPG could not be detected until after the eyes open. These results indicate that lumican is widely distributed in most interstitial connective tissues. The modification of lumican with keratan sulfates in cornea is concurrent with eye opening and may contribute to corneal transparency.
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Affiliation(s)
- S Ying
- Department of Ophthalmology, University of Cincinnati, Cincinnati, Ohio 45267, USA.
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26
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Funderburgh JL, Funderburgh ML, Mann MM, Prakash S, Conrad GW. Synthesis of corneal keratan sulfate proteoglycans by bovine keratocytes in vitro. J Biol Chem 1996; 271:31431-6. [PMID: 8940154 DOI: 10.1074/jbc.271.49.31431] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Keratan sulfate proteoglycans (KSPGs) are the major proteoglycans of the cornea and are secreted by keratocytes in the corneal stroma. Previous studies have been able to show only transient secretion of KSPG in cell culture. In this study, cultures of bovine keratocytes were found to secrete the three previously characterized KSPG proteins into culture medium. Reactivity with monoclonal antibody I22 demonstrated substitution of these proteins with keratan sulfate chains. KSPG constituted 15% of the proteoglycan metabolically labeled with [35S]sulfate in keratocyte culture medium. This labeled KSPG contained keratan sulfate chains of 4700 Da compared to 21,000 Da for bovine corneal keratan sulfate. Labeled keratan sulfate from cultures contained nonsulfated, monosulfated, and disulfated disaccharides that were released by digestion with endo-beta-galactosidase or keratanase II. Nonsulfated disaccharides were relatively more abundant in keratan sulfate from culture than in corneal keratan sulfate. These results show that cultured bovine keratocytes maintain the ability to express all three of the known KSPG proteins, modified with keratan sulfate chains and sulfated on both N-acetylglucosamine and galactose moieties. KSPG made in vitro differs from that found in vivo in the length and sulfation of its keratan sulfate chains. The availability of cell cultures secreting corneal keratan sulfate proteoglycans provides an opportunity to examine biosynthesis and control of this important class of molecules.
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Affiliation(s)
- J L Funderburgh
- Division of Biology, Ackert Hall, Kansas State University, Manhattan, Kansas 66506-4901, USA.
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27
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Gordon MK, Foley JW, Lisenmayer TF, Fitch JM. Temporal expression of types XII and XIV collagen mRNA and protein during avian corneal development. Dev Dyn 1996; 206:49-58. [PMID: 9019246 DOI: 10.1002/(sici)1097-0177(199605)206:1<49::aid-aja5>3.0.co;2-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Using immunohistochemistry and competitive PCR for collagen types XII and XIV, we have followed the expression of these fibril-associated molecules during development of the avian cornea. By immunofluorescence histochemistry, both molecules are found in the acellular primary stroma and are therefore presumably of epithelial origin. During formation and development of the secondary corneal stroma, which is populated by mesenchymal cells, the molecules generally appear to be spatially segregated from each other. Type XIV collagen is found throughout most of the stroma, and therefore is predominantly a product of stromal fibroblasts. During subsequent compaction of the cornea, an event necessary for corneal transparency, the collagen XIV mRNA level increases dramatically, suggesting that this molecule may play a role in this event. Type XII collagen is more localized, occurring mainly in regions of the secondary stroma where matrices interface, such as where Bowman's membrane and Descemet's membrane abut the orthogonally layered collagen fibrils of the stromal matrix. These interfacial regions are highly stable areas of the cornea as determined previously by protease digestion and thermal denaturation studies. Type XII collagen may be involved in this stabilization.
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Affiliation(s)
- M K Gordon
- Department of Anatomy and Cellular Biology, Tufts Medical School, Boston, Massachusetts, USA
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28
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Brown CT, Applebaum E, Banwatt R, Trinkaus-Randall V. Synthesis of stromal glycosaminoglycans in response to injury. J Cell Biochem 1995; 59:57-68. [PMID: 8530537 DOI: 10.1002/jcb.240590108] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Our goal is to examine the synthesis and deposition of corneal glycosaminoglycans (GAGs) in response to a wound created by the insertion of porous discs into stromal interlamellar pockets. The disc and the surrounding stromal tissue were assayed and compared to contralateral control stroma and to sham operated corneas at 14, 42, and 84 days. The tissue and/or discs were removed and labeled with 35S-sulfate for 18 h; GAGs were extracted with 4 M guanidine-HCl. Extracts were chromatographed on Q-Sepharose columns, bound proteoglycans were eluted with a linear salt gradient, and radioactive fractions were analyzed. Total GAG content was determined colorimetrically, using dimethylmethylene blue. Specific GAGs were determined using enzymatic digestion with selective polysaccharide lyases and protein cores were examined using SDS-PAGE. The nonbound fractions from the chromatography were assayed for TGF-beta using Western blot analysis and for hyaluronic acid using an 125I-radiometric assay. Specific GAGs were localized 42 days after the disc had been implanted in the stroma. The placement of the discs into the stroma resulted in a decrease in the total amount of GAG. However, the ratio of dermatan-chondroitin sulfate and heparan sulfate to keratan sulfate increased in the surrounding tissue and disc. Hyaluronic acid was elevated at day 14 in the surrounding tissue, and not until day 84 in the disc. Western blot analysis of surrounding tissue extracts revealed forms of TGF-beta that migrated with an apparent molecular mass of 63 and 43 kDa. The results indicate that the insertion of discs into interlamellar pockets causes changes in the sulfation and proportion of the glycosaminoglycans in the surrounding tissue and the disc. These changes are coincident with the appearance of TGF-beta. After 84 days, the population of glycosaminoglycans in the disc begins to resemble the surrounding stroma. This model will allow us to examine further the synthesis and deposition of proteins following an extensive wound in which cells must migrate to the wound site and then undergo extensive remodeling.
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Affiliation(s)
- C T Brown
- Boston University School of Medicine, Massachusetts 02118, USA
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29
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Birk DE, Nurminskaya MV, Zycband EI. Collagen fibrillogenesis in situ: fibril segments undergo post-depositional modifications resulting in linear and lateral growth during matrix development. Dev Dyn 1995; 202:229-43. [PMID: 7780173 DOI: 10.1002/aja.1002020303] [Citation(s) in RCA: 176] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Elucidating how collagen fibril growth is regulated is important in determining how tissues are assembled. Fibrils are deposited as segments. The growth of these segments is an important determinant of tissue architecture, stability, and mechanical attributes. Fibril segments were isolated from developing tendons and their structure characterized. The post-depositional changes leading to linear and lateral growth of fibrils also were examined. Segments extracted from 14-day chicken embryo tendons had a mean length of 29 microns. The segments were asymmetric, having a short and a long tapered end. Most of the segments were centrosymmetric with respect to molecular packing. Segments extracted from 12- to 16-day tendons had the same structure, but mean segment length increased incrementally due to the addition of an increasingly large population of longer segments. At 17 days of development there was a precipitous increase in segment length. The morphological data indicate that the increase in length was the result of lateral associations among adjacent segments. Analysis demonstrated that this fibril growth was associated with a significant decrease in fibril associated decorin. Using immunoelectron microscopy, decorin was seen to decrease significantly at 18 days of development. When decorin content was biochemically determined, a decrease also was observed. Decorin mRNA also decreased relative to fibrillar collagen mRNA during the same period. These data support the hypothesis that a decrease in fibril-associated decorin is necessary for fibril growth associated with tissue maturation. Growth through post-depositional fusion allows for appositional and intercalary growth and would be essential for normal development, growth, and repair.
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Affiliation(s)
- D E Birk
- Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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30
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De Lisle RC. Characterization of the major sulfated protein of mouse pancreatic acinar cells: a high molecular weight peripheral membrane glycoprotein of zymogen granules. J Cell Biochem 1994; 56:385-96. [PMID: 7876332 DOI: 10.1002/jcb.240560315] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The major sulfated protein of the mouse pancreatic acinar cell, gp300, has been identified and characterized with monoclonal and polyclonal antibodies. gp300 is a glycoprotein of M(r) = 300,000 which contains approximately 40% of metabolically incorporated [35S]sulfate in the acinar cell. Sulfate on gp300 is resistant to hot 1N HCl, but sensitive to alkaline hydrolysis, demonstrating that the sulfate is carbohydrate-linked rather than tyrosine-linked. gp300 metabolically labeled with [3H]glucosamine and [35S]sulfate was chemically and enzymatically treated followed by Bio-Gel P-10 gel filtration. Both labels were resistant to treatments which degrade glycosaminoglycans. Treatment of dual-labeled gp300 with PNGase F to cleave N-linked oligosaccharides released approximately 17% of [3H] and little [35S]. Mild alkaline borohydride treatment after removal of N-linked sugar released the remainder of both labels, indicating the presence of sulfated O-linked oligosaccharides. Biosynthesis studies and PNGase F digestion indicate that the core protein is approximately 210 kDa, with apparent contributions of approximately 35 kDa N-linked sugar, and approximately 55 kDa O-linked sugar. Lectin blotting and glycosidase digestion demonstrated the presence of Gal beta(1-3)GalNAc and sialic acid alpha(2-3)Gal in O-linked oligosaccharide, and Gal beta(1-4)GlcNAc in N-linked oligosaccharide. Immunolocalization and subcellular fractionation showed that gp300 is a peripheral membrane protein localized to the lumenal face of the zymogen granule membrane. gp300 was not secreted in response to hormone stimulation of acini, so it is not a secretory product. Immunoblot analysis showed that gp300 is present in other gastrointestinal tissues and parotid glands. Localization of this nonsecreted sulfated glycoprotein to exocrine secretory granule membranes suggests that gp300 may have a role in granule biogenesis.
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Affiliation(s)
- R C De Lisle
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City 66160
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31
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Doane KJ, Babiarz JP, Fitch JM, Linsenmayer TF, Birk DE. Collagen fibril assembly by corneal fibroblasts in three-dimensional collagen gel cultures: small-diameter heterotypic fibrils are deposited in the absence of keratan sulfate proteoglycan. Exp Cell Res 1992; 202:113-24. [PMID: 1511726 DOI: 10.1016/0014-4827(92)90410-a] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Extracellular matrix assembly is a multistep process and the various steps in collagen fibrillogenesis are thought to be influenced by a number of factors, including other noncollagenous matrix molecules. The synthesis and deposition of extracellular matrix by corneal fibroblasts grown within three-dimensional collagen gel cultures were examined to elucidate the factors important in the establishment of tissue-specific matrix architecture. Corneal fibroblasts in collagen gel cultures form layers and deposit small-diameter collagen fibrils (approximately 25 nm) typical of the mature corneal stroma. The matrix synthesized contains type VI collagen in a filamentous network and type I and type V collagen assembled as heterotypic fibrils. The amount of type V collagen synthesized is relatively high and comparable to that seen in the corneal stroma. This matrix is deposited between cell layers in a manner reminiscent of the secondary corneal stroma, but is not deposited as densely or as organized as would be found in situ. No keratan sulfate proteoglycan, a proteoglycan found only in the corneal stroma, was synthesized by the fibroblasts in the collagen gel cultures. The assembly and deposition of small-diameter fibrils with a collagen composition and structure identical to that seen in the corneal stroma in the absence of proteoglycans typical of the secondary corneal stroma imply that although proteoglycan-collagen interactions may function in the establishment of interfibrillar spacing and lamellar organization, collagen-collagen interactions are the major parameter in the regulation of fibril diameter.
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Affiliation(s)
- K J Doane
- Department of Pathology, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635
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Galbraith DB, Cutler LS, Kollar EJ. The correlation of temporal regulation of glycosaminoglycan synthesis with morphogenetic events in mouse tooth development. Arch Oral Biol 1992; 37:623-8. [PMID: 1514935 DOI: 10.1016/0003-9969(92)90124-q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The purpose of this study was to investigate the pattern of sulphated glycosaminoglycan synthesis during morphogenesis and cytodifferentiation in mouse tooth rudiments and to compare the results with those obtained in another study for salivary gland, a branched organ. Sulphated glycosaminoglycan was labelled by incubating molar rudiments from day 15 of gestation to day 1 post partum in medium containing [35S]-sodium sulphate. The rudiments were washed, homogenized and digested in pronase and then were sequentially digested by chondroitinase ABC and chemically degraded by nitrous acid oxidation. The fractions from each of these procedures were analysed by chromatography on Sephadex G-50 columns. The analysis revealed that, during morphogenesis, levels of chondroitin sulphate increased to a peak of 91% at day 18 and levels of heparan sulphate diminished to 8% during this period. As cytodifferentiation occurred, the level of chondroitin sulphate dropped to 64% and that of heparan sulphate increased to 35%. These results are similar to those reported for rat submaxillary gland, a branching organ. It appears that this pattern of sulphated glycosaminoglycan synthesis is not a unique feature of branching morphogenesis but may be one which marks the transition between morphogenesis and cytodifferentiation in non-branching rudiments as well.
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Affiliation(s)
- D B Galbraith
- Department of Biology, Trinity College, Hartford, CT 06106
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33
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Kratz-Owens KL, Hageman GS, Schanzlin DJ. An In-Vivo Technique for Monitoring Keratocyte Migration Following Lamellar Keratoplasty. J Refract Surg 1992. [DOI: 10.3928/1081-597x-19920501-10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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34
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cDNA to chick lumican (corneal keratan sulfate proteoglycan) reveals homology to the small interstitial proteoglycan gene family and expression in muscle and intestine. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)48500-6] [Citation(s) in RCA: 163] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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35
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Schrecengost PK, Blochberger TC, Hassell JR. Identification of chick corneal keratan sulfate proteoglycan precursor protein in whole corneas and in cultured corneal fibroblasts. Arch Biochem Biophys 1992; 292:54-61. [PMID: 1727651 DOI: 10.1016/0003-9861(92)90050-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The precursor protein to the chick corneal keratan sulfate proteoglycan was identified by immunoprecipitation with antiserum to its core protein from lysates of [35S]methionine-pulsed corneas and corneal fibroblasts in cell culture. Antiserum to the keratan sulfate proteoglycan immunoprecipitated a doublet of Mr 52,000 and 50,000 and minor amounts of a Mr 40,000 protein from pulsed corneas. Pulse-chase experiments, which permitted the conversion of the precursor proteins to proteoglycans and digestion of the glycosaminoglycans on immunoprecipitated proteoglycans with keratanase or chondroitinase ABC, showed that the Mr 52,000-50,000 doublet was converted to a keratan sulfate proteoglycan and the Mr 40,000 protein was converted to a chondroitin sulfate proteoglycan. Chick corneal fibroblasts in cell culture primarily produced the smaller (Mr50,000) precursor protein, and in the presence of tunicamycin the precursor protein size was reduced to Mr35,000, which indicates that the core protein contains approximately five N-linked oligosaccharides. Pulse-chase experiments with corneal fibroblasts in culture showed that the precursor protein was processed and secreted into the medium. However, its sensitivity to endo-beta-galactosidase and resistance to keratanase indicate that the precursor protein was converted to a glycoprotein with large oligosaccharides and not to a proteoglycan. This suggests that, although the precursor protein for the proteoglycan is produced in cultured corneal fibroblasts, the sulfation enzymes for keratan sulfate may be absent.
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Affiliation(s)
- P K Schrecengost
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pennsylvania
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36
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Cutler LS, Christian CP, Rendell JK. Sulphated glycosaminoglycan synthesis by developing rat submandibular gland secretory units. Arch Oral Biol 1991; 36:389-95. [PMID: 1908218 DOI: 10.1016/0003-9969(91)90010-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This study examined the profile of S-GAGs synthesized by presecretory and secretory units isolated from rats at 17, 18 and 21 days in utero and 1, 6 and 35 days after birth. The units were incubated for 2 h in medium containing [35S]-sodium sulphate and then processed and analysed. Secretory units from 17-day embryonic presecretory units produced a S-GAG profile composed of approx. 73% chondroitin sulphate and 26% heparan sulphate. When cells of the embryonic units undergo cytodifferentiation to become secretory cells (18 days in utero), there is a major change in the relative amounts of S-GAG synthesized with 54% of the S-GAG produced being heparan sulphate and 41% chondroitin sulphate. There is a progressive increase in the relative amount of heparan sulphate produced and a concomitant decline in chondroitin sulphate as the secretory compartment of the gland matures. By 35 days after birth, the secretory units produced a S-GAG profile that was greater than 85% heparan sulphate and less than 10% chondroitin sulphate. The ratio of heparan sulphate/chondroitin sulphate production was 0.36 by 17-day embryonic presecretory units and shifted to 9.1 by 35-day postnatal units.
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Affiliation(s)
- L S Cutler
- Department of Oral Diagnosis, School of Dental Medicine, University of Connecticut Health Center, Farmington 06032
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37
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Proteoglycan biosynthesis by human corneas from patients with types 1 and 2 macular corneal dystrophy. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)55489-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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38
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Dubaybo BA, Thet LA. Effect of transforming growth factor beta on synthesis of glycosaminoglycans by human lung fibroblasts. Exp Lung Res 1990; 16:389-403. [PMID: 2226352 DOI: 10.3109/01902149009068816] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The processes of lung growth, injury, and repair are characterized by alterations in fibroblast synthesis and interstitial distribution of extracellular matrix components. Transforming growth factor beta (TGF-beta), which is postulated to play a role in modulating lung repair, alters the distribution of several matrix components such as collagen and fibronectin. We studied the effect of TGF-beta on the synthesis and distribution of the various glycosaminoglycans (GAGs) and whether these effects may explain its role in lung repair. Human diploid lung fibroblasts (IMR-90) were exposed to various concentrations of TGF-beta (0-5 nM) for variable periods of time (0-18 h). Newly synthesized GAGs were labeled with either [3H]glucosamine or [35S]sulfate. Individual GAGs were separated by size exclusion chromatography after serial enzymatic and chemical digestions and quantitated using scintillation counting. There was a dose-dependent increase in total GAG synthesis with maximal levels detected after 6 h of exposure. This increase was noted in all individual GAG types measured and was observed in both the cell associated GAGs (cell-matrix fraction) as well as the GAGs released into the medium (medium fraction). In the cell-matrix fraction, TGF-beta increased the proportion of heparan sulfate that was membrane bound as well as the proportion of dermatan sulfate in the intracellular compartment. In the medium fraction, TGF-beta increased the proportion of hyaluronic acid, chondroitin sulfate and dermatan sulfate released. We conclude that the role of TGF-beta in lung growth and repair may be related to increased synthesis of GAGs by human lung fibroblasts as well as alterations in the distribution of individual GAGs.
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Affiliation(s)
- B A Dubaybo
- Veterans Administration Medical Center, Allen Park, Michigan 48101
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39
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Midura RJ, Hascall VC. Analysis of the Proteoglycans Synthesized by Corneal Explants from Embryonic Chicken. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)94204-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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40
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Midura RJ, Toledo OMS, Yanagishita M, Hascall VC. Analysis of the Proteoglycans Synthesized by Corneal Explants from Embryonic Chicken. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(18)94203-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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41
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Giacoletto KS, Rumbarger T, Schwartz BD. Glycosaminoglycan modifications of membrane proteins. Methods Cell Biol 1989; 32:207-30. [PMID: 2691851 DOI: 10.1016/s0091-679x(08)61172-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- K S Giacoletto
- Howard Hughes Medical Institute, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
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42
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Mina M, Rossomando EF. Assay of ATP-sulfurylase activity from rat liver by high-performance liquid chromatography. JOURNAL OF CHROMATOGRAPHY 1988; 433:63-72. [PMID: 2853170 DOI: 10.1016/s0378-4347(00)80585-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Alteration of proteoglycan composition is known to accompany morphogenesis. In many tissues one such alteration is the removal of hyaluronate and its replacement with a sulfated proteoglycan. Several mechanisms that could regulate this alteration have been studied leading to a hypothesis that the increase in the sulfated proteoglycan is regulated by controlling the activity of those enzymes involved in the activation of the sulfate. To measure any variations in these activities usually begins with a purification of the enzyme. However, this procedure is difficult to perform where tissue samples are difficult to obtain in large enough quantities. Therefore, the examination of an enzymatic activity when tissue samples are in short supply requires the development of methods for the assay of the specific activity after a minimum of purification. In this paper we report on the development of just such an assay for ATP-sulfurylase, the enzyme that catalyses the first step in the activation of sulfate. This method uses anion-exchange high-performance liquid chromatography and differs from a previously published procedure [F. A. Hommes and L. Moss, Anal. Biochem., 154 (1986) 100] in that the compounds are detected spectrophotometrically instead of radiometrically and also in that the ATP, ADP, AMP and their sulfated analogues, adenosine 5'-phosphosulfate and 3'-phosphoadenosine 5'-phosphosulfate, are separated isocratically. Studies performed with 35SO4(2-) were used to validate this new method. The separation of all these compounds has allowed us to develop a one-step, on-line assay procedure which can be performed on small samples of partially purified preparations. We have used this procedure to measure the activity of the ATP sulfurylase in extracts of rat liver and tongue. Our results indicated that the ATP-sulfurylase activity from rat liver was soluble with a pH optimum of 8.0. The identity of the reaction product was verified using radiolabeled sulfate as the substrate and recovering the radiolabel in the product. Preliminary kinetic studies with this method showed the sulfurylase activity to have an apparent Michaelis constant of 3 microM and a maximal velocity of 0.56 pmol/min per mg protein.
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Affiliation(s)
- M Mina
- Department of BioStructure and Function, University of Connecticut Health Center, Farmington 06032
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43
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Greve H, Cully Z, Blumberg P, Kresse H. Influence of chlorate on proteoglycan biosynthesis by cultured human fibroblasts. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37644-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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44
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Abstract
Cytochrome oxidase (CO) activity on alkali-burned rabbit corneas was investigated histochemically to determine the metabolic change in inflamed corneas during wound healing. Cryostat sections of chemically burned and mechanically scraped corneas were stained for CO activity, which is regarded as an index of metabolic activity. Following chemical injury, positive CO activity was detected initially in the vascular endothelial cells of limbal blood vessels. Numerous active polymorphonuclear leukocytes (PMNs) and monocytes were found intravascularly and perivascularly. Fibroblasts that appeared at the wound site exhibited marked CO activity around the limbus. Over a period of 13 days, PMNs gradually invaded the central cornea, followed by fibroblasts of high metabolic activity. The areas of PMN infiltration were the same areas in which fibroblasts showed intense staining, suggesting that a PMN-derived mediator or secondary products might affect the activation of fibroblasts. Epithelial resurfacing was delayed in the chemically burned corneas, although reepithelialization was completed within two to three days in the scraped corneas. Limbal epithelial cells, which recently were suggested as the source of epithelial renewal, showed a remarkable increase of metabolic activity in response to chemical inflammatory stimulation, whereas those in the scraped model did not. This suggests that epithelial cell renewal at the limbus was accelerated in the presence of disturbed reepithelialization.
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Affiliation(s)
- K Hayashi
- Cornea Unit, Massachusetts Eye and Ear Infirmary, Boston
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45
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Sugahara K, Okamoto H, Nakamura M, Shibamoto S, Yamashina I. Developmental changes in glycosaminoglycan sulfotransferase activities in animal sera. Arch Biochem Biophys 1987; 258:391-403. [PMID: 3479049 DOI: 10.1016/0003-9861(87)90360-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Glycosaminoglycan sulfotransferase activities in sera during the prenatal and postnatal development of the ox, rat, and chicken were systematically measured with chemically desulfated cartilage chondroitin 4-sulfate, cornea keratan sulfate, and kidney heparan sulfate as exogenous sulfate acceptors and with [35S]sulfate-labeled 3'-phosphoadenosine 5'-phosphosulfate as a sulfate donor. The results of specificity studies and product analyses indicated that these enzymes introduce sulfates at position 6 of the internal N-acetylgalactosamine units of chondroitin, position 6 of the galactose units of keratan sulfate, and position 2 (an amino group) of the glucosamine units of heparan sulfate, respectively. The results of the enzyme assays indicated that (1) the three activities change in a development-associated manner in each animal species, (2) generally, the activities of the former two enzymes decrease with embryonic development and aging after birth, although in chicken serum they increase transiently at the late prenatal stage and decrease thereafter, and (3) the pattern of the changes in heparan sulfate sulfotransferase activity is species-dependent: the activity increases in the rat, decreases in the ox, and does not significantly change in the chicken during prenatal or postnatal development. These alterations may reflect development-associated biosynthesis of the corresponding glycosaminoglycans or maturation of the proteoglycans in some tissues.
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Affiliation(s)
- K Sugahara
- Department of Biological Chemistry, Faculty of Pharmaceutical Sciences, Kyoto University, Japan
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46
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Cutler LS, Christian CP, Rendell JK. Glycosaminoglycan synthesis by adult rat submandibular salivary-gland secretory units. Arch Oral Biol 1987; 32:413-9. [PMID: 3118858 DOI: 10.1016/0003-9969(87)90076-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The synthesis of glycosaminoglycans (GAG) by a preparation of purified, functional submandibular-gland secretory units (acini and intercalated ducts) was examined. Such units were isolated from Sprague-Dawley rats by digestion of minced gland with hyaluronidase and collagenase followed by gentle sieving of the digest through a graded series of Teflon screens. They incorporated amino acids into exocrine proteins which could be released by stimulation with isoproterenol as in vivo, indicating their functional integrity. Secretory units, incubated for 2 h in medium containing [35S]-sodium sulphate alone or in combination with [3H]-glucosamine, were then washed, homogenized and digested in pronase. The resulting material was then sequentially digested by specific enzymic and chemical procedures and analysed by chromatography on Sephadex G-50 columns to identify the various GAG synthesized. Secretory units synthesized a GAG mixture which was 20-25 per cent hyaluronic acid, 70-75 per cent heparan sulphate, and only 3-5 per cent chondroitin or dermatan sulphates, similar to that synthesized in vivo. No GAG was present in the secretory material, suggesting that all the GAG synthesized was destined for the basement membrane or cell surface.
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Affiliation(s)
- L S Cutler
- Department of Oral Diagnosis, University of Connecticut School of Dental Medicine, Farmington 06032
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47
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Crean EV, Tyson SL, Richardson TM. Factors influencing glycosaminoglycan synthesis by calf trabecular meshwork cell cultures. Exp Eye Res 1986; 43:365-74. [PMID: 3780879 DOI: 10.1016/s0014-4835(86)80073-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
When cell or explant cultures were established from excised calf aqueous outflow pathway tissue and subsequently labeled with radioactive precursors of glycosaminoglycans [( 3H]glucosamine and [35S]sulfate), hyaluronic acid was the predominant glycosaminoglycan produced initially. As the cultures reached confluence, sulfated glycosaminoglycans became more prominent products. Further investigation revealed that the cultured trabecular cells could synthesize all of the glycosaminoglycans found in isolated calf trabecular tissue once a critical cell density had been attained. Increasing concentrations of fetal bovine serum in the culture medium stimulated glycosaminoglycan accumulation without altering the quantitative distribution of the various glycosaminoglycan products. Treatment of confluent monolayers with enzymes capable of degrading extracellular matrix molecules caused marked changes in the distribution of glycosaminoglycans produced by calf trabecular-cell cultures. The results suggest that calf trabecular cell cultures can be used to study the dynamics of extracellular matrix production and turnover under controlled experimental conditions.
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48
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Funderburgh JL, Caterson B, Conrad GW. Keratan sulfate proteoglycan during embryonic development of the chicken cornea. Dev Biol 1986; 116:267-77. [PMID: 2942429 DOI: 10.1016/0012-1606(86)90130-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Antibodies to corneal keratan sulfate proteoglycan (KSPG) were used to characterize the pattern of KSPG accumulation during differentiation of neural crest cells in the stroma of embryonic chick cornea. Immunohistochemistry with monoclonal antibody I22 to keratan sulfate found this KSPG antigen localized inside stromal cells at stage 29 (Day 6), ca. 12 hr after migration into the primary stroma. A 2- to 3-day lag then occurred before appearance of extracellular keratan sulfate, first seen on Day 9 (Stage 35) in the posterior stroma. Keratan sulfate antigen accumulated in a posterior to anterior direction during subsequent development. Uniform staining of the stroma for keratan sulfate did not occur until after Day 16. Among several tissues, only corneal stroma contained an extracellular matrix which stained for keratan sulfate, though intracellular staining of some cartilage cells was observed. Accumulation of KSPG antigens in developing cornea was measured in unfractionated guanidine extracts with a quantitative ELISA using three different antibodies against KSPG. Increases were first detected after Day 9 using monoclonal I22, and somewhat later with the other two antibodies. Assays with all three antibodies detected a sustained, exponential increase of KSPG throughout the 5 days prior to hatching. Keratan sulfate continued to accumulate after hatching, but an antibody with specificity to KSPG core protein, detected no relative increase in antigen after hatching. This suggests a modulation of KSPG primary structure late in development and after hatching. Overt differentiation of individual neural crest cells thus appears to begin ca. 12 hr after their arrival in the primary stroma; a lag of 2-3 days precedes active secretion of KSPG.
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49
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Torres CR, Hart GW. Topography and polypeptide distribution of terminal N-acetylglucosamine residues on the surfaces of intact lymphocytes. Evidence for O-linked GlcNAc. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)43295-9] [Citation(s) in RCA: 778] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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50
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Abstract
Gel chromatography, affinity chromatography, ultracentrifugation, enzymic fragmentation, and analysis of amino acids, hexosamines and neutral sugars were used to characterize a heterogeneous fraction of proteoglycans from bovine corneal stroma. The results indicate that the fraction largely consists of a mixture of the 2 main types of corneal proteoglycans described earlier, namely keratan sulfate proteoglycans and chondroitin sulfate-rich proteoglycans with covalently bound oligosaccharides. Models for the structure of proteoglycans are suggested, an it is concluded that the molecular size of corneal proteoglycans makes them appropriate as 'spacers' between the collagen fibrils, a property important for corneal transparency. Cornea is softer than cartilage because corneal proteoglycans are less underhydrated than cartilage proteoglycans.
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