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Chandra N, Liu Y, Liu JX, Frängsmyr L, Wu N, Silva LM, Lindström M, Chai W, Pedrosa Domellöf F, Feizi T, Arnberg N. Sulfated Glycosaminoglycans as Viral Decoy Receptors for Human Adenovirus Type 37. Viruses 2019; 11:E247. [PMID: 30871026 PMCID: PMC6466042 DOI: 10.3390/v11030247] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/07/2019] [Accepted: 03/09/2019] [Indexed: 12/13/2022] Open
Abstract
Glycans on plasma membranes and in secretions play important roles in infection by many viruses. Species D human adenovirus type 37 (HAdV-D37) is a major cause of epidemic keratoconjunctivitis (EKC) and infects target cells by interacting with sialic acid (SA)-containing glycans via the fiber knob domain of the viral fiber protein. HAdV-D37 also interacts with sulfated glycosaminoglycans (GAGs), but the outcome of this interaction remains unknown. Here, we investigated the molecular requirements of HAdV-D37 fiber knob:GAG interactions using a GAG microarray and demonstrated that fiber knob interacts with a broad range of sulfated GAGs. These interactions were corroborated in cell-based assays and by surface plasmon resonance analysis. Removal of heparan sulfate (HS) and sulfate groups from human corneal epithelial (HCE) cells by heparinase III and sodium chlorate treatments, respectively, reduced HAdV-D37 binding to cells. Remarkably, removal of HS by heparinase III enhanced the virus infection. Our results suggest that interaction of HAdV-D37 with sulfated GAGs in secretions and on plasma membranes prevents/delays the virus binding to SA-containing receptors and inhibits subsequent infection. We also found abundant HS in the basement membrane of the human corneal epithelium, which may act as a barrier to sub-epithelial infection. Collectively, our findings provide novel insights into the role of GAGs as viral decoy receptors and highlight the therapeutic potential of GAGs and/or GAG-mimetics in HAdV-D37 infection.
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Affiliation(s)
- Naresh Chandra
- Section of Virology, Department of Clinical Microbiology, Umeå University, SE-90185 Umeå, Sweden.
| | - Yan Liu
- Glycosciences Laboratory, Faculty of Medicine, Imperial College of London, Hammersmith Campus, London W12 0NN, UK.
| | - Jing-Xia Liu
- Department of Integrative Medical Biology, Umeå University, SE-90185 Umeå, Sweden.
- Department of Clinical Science, Ophthalmology, Umeå University, SE-90185 Umeå, Sweden.
| | - Lars Frängsmyr
- Section of Virology, Department of Clinical Microbiology, Umeå University, SE-90185 Umeå, Sweden.
| | - Nian Wu
- Glycosciences Laboratory, Faculty of Medicine, Imperial College of London, Hammersmith Campus, London W12 0NN, UK.
| | - Lisete M Silva
- Glycosciences Laboratory, Faculty of Medicine, Imperial College of London, Hammersmith Campus, London W12 0NN, UK.
| | - Mona Lindström
- Department of Integrative Medical Biology, Umeå University, SE-90185 Umeå, Sweden.
- Department of Clinical Science, Ophthalmology, Umeå University, SE-90185 Umeå, Sweden.
| | - Wengang Chai
- Glycosciences Laboratory, Faculty of Medicine, Imperial College of London, Hammersmith Campus, London W12 0NN, UK.
| | - Fatima Pedrosa Domellöf
- Department of Integrative Medical Biology, Umeå University, SE-90185 Umeå, Sweden.
- Department of Clinical Science, Ophthalmology, Umeå University, SE-90185 Umeå, Sweden.
| | - Ten Feizi
- Glycosciences Laboratory, Faculty of Medicine, Imperial College of London, Hammersmith Campus, London W12 0NN, UK.
| | - Niklas Arnberg
- Section of Virology, Department of Clinical Microbiology, Umeå University, SE-90185 Umeå, Sweden.
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Andrade AL, Campos MQ, Gomes JAP, Berto AGA, Michelacci YM. Effect of Amniotic Membrane Transplantation on Corneal Healing and Proteoglycan Expression in an Experimental Model of Limbal Deficiency in Rabbits. Eur J Ophthalmol 2018; 20:290-9. [DOI: 10.1177/112067211002000206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Alexandre L. Andrade
- Department of Clinical Surgery and Animal Reproduction, Universidade Estadual Paulista, Araçatuba
| | - Mauro Q. Campos
- Department of Ophthalmology, Universidade Federal de São Paulo, São Paulo - Brazil
| | - José A. P. Gomes
- Department of Ophthalmology, Universidade Federal de São Paulo, São Paulo - Brazil
| | | | - Yara M. Michelacci
- Department of Biochemistry, Universidade Federal de São Paulo, São Paulo - Brazil
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da Cunha AL, Aguiar JA, Correa da Silva FS, Michelacci YM. Do chondroitin sulfates with different structures have different activities on chondrocytes and macrophages? Int J Biol Macromol 2017; 103:1019-1031. [DOI: 10.1016/j.ijbiomac.2017.05.123] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/08/2017] [Accepted: 05/19/2017] [Indexed: 01/22/2023]
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Massoudi D, Malecaze F, Galiacy SD. Collagens and proteoglycans of the cornea: importance in transparency and visual disorders. Cell Tissue Res 2015. [PMID: 26205093 DOI: 10.1007/s00441-015-2233-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The cornea represents the external part of the eye and consists of an epithelium, a stroma and an endothelium. Due to its curvature and transparency this structure makes up approximately 70% of the total refractive power of the eye. This function is partly made possible by the particular organization of the collagen extracellular matrix contained in the corneal stroma that allows a constant refractive power. The maintenance of such an organization involves other molecules such as type V collagen, FACITs (fibril-associated collagens with interrupted triple helices) and SLRPs (small leucine-rich proteoglycans). These components play crucial roles in the preservation of the correct organization and function of the cornea since their absence or modification leads to abnormalities such as corneal opacities. Thus, the aim of this review is to describe the different corneal collagens and proteoglycans by highlighting their importance in corneal transparency as well as their implication in corneal visual disorders.
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Affiliation(s)
| | - Francois Malecaze
- EA4555, Université Toulouse III Paul Sabatier, Toulouse, France
- CHU Toulouse, Hôpital Purpan, Service d'Ophtalmologie, Toulouse, France
| | - Stephane D Galiacy
- EA4555, Université Toulouse III Paul Sabatier, Toulouse, France.
- CHU Toulouse, Hôpital Purpan, Service d'Ophtalmologie, Toulouse, France.
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Iwatsuka K, Iwamoto H, Kinoshita M, Inada K, Yasueda SI, Kakehi K. Comparative Studies ofN-Glycans and Glycosaminoglycans Present in SIRC (Statens Seruminstitut Rabbit Cornea) Cells and Corneal Epithelial Cells from Rabbit Eyes. Curr Eye Res 2014; 39:686-94. [DOI: 10.3109/02713683.2013.863940] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Dyrlund TF, Poulsen ET, Scavenius C, Nikolajsen CL, Thøgersen IB, Vorum H, Enghild JJ. Human cornea proteome: identification and quantitation of the proteins of the three main layers including epithelium, stroma, and endothelium. J Proteome Res 2012; 11:4231-9. [PMID: 22698189 PMCID: PMC3411198 DOI: 10.1021/pr300358k] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Diseases of the cornea are common and refer to conditions like infections, injuries and genetic defects. Morphologically, many corneal diseases affect only certain layers of the cornea and separate analysis of the individual layers is therefore of interest to explore the basic molecular mechanisms involved in corneal health and disease. In this study, the three main layers including, the epithelium, stroma and endothelium of healthy human corneas were isolated. Prior to analysis by LC-MS/MS the proteins from the different layers were either (i) separated by SDS-PAGE followed by in-gel trypsinization, (ii) in-solution digested without prior protein separation or, (iii) in-solution digested followed by cation exchange chromatography. A total of 3250 unique Swiss-Prot annotated proteins were identified in human corneas, 2737 in the epithelium, 1679 in the stroma, and 880 in the endothelial layer. Of these, 1787 proteins have not previously been identified in the human cornea by mass spectrometry. In total, 771 proteins were quantified, 157 based on in-solution digestion and 770 based on SDS-PAGE separation followed by in-gel digestion of excised gel pieces. Protein analysis showed that many of the identified proteins are plasma proteins involved in defense responses.
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Affiliation(s)
- Thomas F Dyrlund
- Interdisciplinary Nanoscience Center (iNANO) and Department of Molecular Biology, Aarhus University, and Department of Ophthalmology, Aalborg Hospital, Denmark
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de Lima CR, de Arimatéa dos Santos Junior J, Nazário ACP, Michelacci YM. Changes in glycosaminoglycans and proteoglycans of normal breast and fibroadenoma during the menstrual cycle. Biochim Biophys Acta Gen Subj 2012; 1820:1009-19. [PMID: 22542782 DOI: 10.1016/j.bbagen.2012.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 04/10/2012] [Accepted: 04/11/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND Fibroadenoma is the most common breast tumor in young women, and its growth and metabolism may be under hormonal control. In the present paper we described the proteoglycan (PG) composition and synthesis rate of normal breast and fibroadenoma during the menstrual cycle. METHODS Samples of fibroadenoma and adjacent normal breast tissue were obtained at surgery. PGs were characterized by agarose gel electrophoresis and enzymatic degradation with glycosaminoglycan (GAG) lyases, and immunolocalized by confocal microscopy. To assess the synthesis rate, PGs were metabolic labeled by 35S-sulfate. RESULTS The concentration of PGs in normal breast was higher during the secretory phase. Fibroadenoma contained and synthesized more PGs than their paired controls, but the PG concentrations varied less with the menstrual cycle and, in contrast to normal tissue, peaked in the proliferative phase. The main mammary GAGs are heparan sulfate (HS, 71%-74%) and dermatan sulfate (DS, 26%-29%). The concentrations of both increased in fibroadenoma, but DS increased more, becoming 35%-37% of total. The DS chains contained more β-d-glucuronic acid (IdoUA/GlcUA ratios were >10 in normal breast and 2-7 in fibroadenoma). The 35S-sulfate incorporation rate revealed that the in vitro synthesis rate of DS was higher than HS. Decorin was present in both tissues, while versican was found only in fibroadenoma. CONCLUSIONS In normal breast, the PG concentration varied with the menstrual cycle. It was increased in fibroadenoma, especially DS. GENERAL SIGNIFICANCE PGs are increased in fibroadenoma, but their concentrations may be less sensitive to hormonal control.
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Affiliation(s)
- Cilene Rebouças de Lima
- Disciplina de Biologia Molecular, Departamento de Bioquímica, Escola Paulista de Medicina, Universidade Federal de São Paulo-UNIFESP, São Paulo, SP, Brazil
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Borges F, Dalboni M, Michelacci Y, Schor N. Noncrystalline uric acid inhibits proteoglycan and glycosaminoglycan synthesis in distal tubular epithelial cells (MDCK). Braz J Med Biol Res 2010; 43:957-63. [DOI: 10.1590/s0100-879x2010007500095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 08/19/2010] [Indexed: 11/21/2022] Open
Affiliation(s)
| | | | | | - N. Schor
- Universidade Federal de São Paulo
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Meek KM, Boote C. The use of X-ray scattering techniques to quantify the orientation and distribution of collagen in the corneal stroma. Prog Retin Eye Res 2009; 28:369-92. [PMID: 19577657 DOI: 10.1016/j.preteyeres.2009.06.005] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The bulk of the corneal stroma is comprised of a layered network of fibrillar collagen. Determining the architecture of this unique structure may help us to better understand the cornea's biomechanical and optical function. The analysis of diffraction patterns obtained when X-rays are passed through the regularly arranged collagen molecules and fibrils of the stromal matrix yields quantitative data on fibrillar organisation, including the orientation and distribution of collagen lamellae within the corneal plane. In recent years, by exploiting the radiation from powerful synchrotron sources, techniques have been developed to enable the mapping of collagen fibril, and therefore lamellar, directions across whole corneas. This article aims to summarise the use of X-ray diffraction to map the orientation and distribution of collagen in the corneal stroma. The implications of the knowledge gained so far are discussed in relation to the optical and biomechanical properties of the cornea, and their alteration due to disease and surgical intervention.
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Affiliation(s)
- Keith M Meek
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.
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Hornof M, de la Fuente M, Hallikainen M, Tammi RH, Urtti A. Low molecular weight hyaluronan shielding of DNA/PEI polyplexes facilitates CD44 receptor mediated uptake in human corneal epithelial cells. J Gene Med 2008; 10:70-80. [PMID: 18044795 DOI: 10.1002/jgm.1125] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
AIM It was the aim of this study to prepare purified DNA/PEI polyplexes, which are coated with hyaluronan to facilitate CD44 receptor mediated uptake of the DNA/PEI polyplex and to reduce unspecific interactions of the complex with negatively charged extracellular matrix components on the ocular surface. METHODS Hyaluronans of different molecular weights (<10 kDa, 10-30 kDa and 30-50 kDa) were isolated after enzymatic degradation of high molecular weight hyaluronan via ultrafiltration by centrifugation. The influence of the different hyaluronans used for coating on the stability and transfection efficiency of the complexes was evaluated in vitro. Transfection and uptake studies were performed in human corneal epithelial (HCE) cells. CD44 receptor expression of this cell model was evaluated by immunohistochemistry. RESULTS Coating of purified DNA/PEI polyplexes with low molecular weight hyaluronan (<10 kDa) facilitated receptor-mediated uptake via the CD44 receptor in HCE cells, increased complex stability in vitro, and effectively shielded the positive surface charges of the polyplex without decreasing its transfection efficiency. Higher molecular weights and larger amounts of hyaluronan in the complexes resulted in lesser improvements in the stability and transfection efficacy of the complexes. CONCLUSIONS Coating of polyplexes with low molecular weight hyaluronan is a promising strategy for gene delivery to the ocular surface, where CD44 receptor mediated uptake decreased cytotoxicity and reduced non-specific interactions with the negatively charged extracellular matrix components are considered beneficial for increased transfection efficiency of non-viral vectors.
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Affiliation(s)
- Margit Hornof
- Drug Discovery and Development Technology Center DDTC, University of Helsinki, Finland
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Borges F, Garofalo A, Dalboni M, Abreu N, Michelacci Y, Schor N. The Effects of Lipopolysaccharide-Induced Reactive Oxygen Species Were Blunted by Calcium Oxalate in Renal Tubular Epithelial Cells. ACTA ACUST UNITED AC 2008; 108:e35-44. [DOI: 10.1159/000115027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Accepted: 11/07/2007] [Indexed: 11/19/2022]
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Borges FT, Michelacci YM, Aguiar JAK, Dalboni MA, Garófalo AS, Schor N. Characterization of glycosaminoglycans in tubular epithelial cells: calcium oxalate and oxalate ions effects. Kidney Int 2005; 68:1630-42. [PMID: 16164640 DOI: 10.1111/j.1523-1755.2005.00577.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The interaction between tubular epithelial cells and calcium oxalate crystals or oxalate ions is a very precarious event in the lithogenesis. Urine contains ions, glycoproteins and glycosaminoglycans that inhibit the crystallization process and may protect the kidney against lithogenesis. We examined the effect of oxalate ions and calcium oxalate crystals upon the synthesis of glycosaminoglycans in distal [Madin-Darby canine kidney (MDCK)] and proximal (LLC-PK1) tubular cell lines. METHODS Glycosaminoglycan synthesis was analyzed by metabolic labeling with (35)S-sulfate and enzymatic digestion with specific mucopolysaccharidases. Cell death was assessed by fluorescent dyes and crystal endocytosis was analised by flow cytometry. RESULTS The main glycosaminoglycans synthesized by both cells were chondroitin sulfate and heparan sulfate most of them secreted to the culture medium or present at cellular surface. Exposition of MDCK cells to oxalate ions increased apoptosis rate and the incorporation of (35)S-sulfate in chondroitin sulfate and heparan sulfate, while calcium oxalate crystals were endocyted by LLC-PK1, induced necrotic cell death, and increased (35)S-sulfate incorporation in glycosaminoglycans. These effects seem to be specific and due to increased biosynthesis, since hydroxyapatite and other carboxylic acid did not induced cellular death or glycosaminoglycan synthesis and no changes in sulfation degree or molecular weight of glycosaminoglycans could be detected. Thapsigargin inhibited the glycosaminoglycan synthesis induced by calcium oxalate in LLC-PK1, suggesting that this effect was sensitive to the increase in cytosolic calcium. CONCLUSION Tubular cells may increase the synthesis of glycosaminoglycans to protect from the toxic insult of calcium oxalate crystals and oxalate ions, what could partially limit the lithogenesis.
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Affiliation(s)
- Fernanda T Borges
- Departamento de Medicina, Disciplina de Nefrologia, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brasil
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Abstract
The cornea is a curved and transparent structure that provides the initial focusing of a light image into the eye. It consists of a central stroma that constitutes 90% of the corneal depth, covered anteriorly with epithelium and posteriorly with endothelium. Its transparency is the result of the regular spacing of collagen fibers with remarkably uniform diameter and interfibrillar space. Corneal collagen is composed of heterotypic fibrils consisting of type I and type V collagen molecules. The cornea also contains unusually high amounts of type VI collagen, which form microfibrillar structures, FACIT collagens (XII and XIV), and other nonfibrillar collagens (XIII and XVIII). FACIT collagens and other molecules, such as leucine-rich repeat proteoglycans, play important roles in modifying the structure and function of collagen fibrils.Proteoglycans are macromolecules composed of a protein core with covalently linked glycosaminoglycan side chains. Four leucine-rich repeat proteoglycans are present in the extracellular matrix of corneal stroma: decorin, lumican, mimecan and keratocan. The first is a dermatan sulfate proteoglycan, and the other three are keratan sulfate proteoglycans. Experimental evidence indicates that the keratan sulfate proteoglycans are involved in the regulation of collagen fibril diameter, and dermatan sulfate proteoglycan participates in the control of interfibrillar spacing and in the lamellar adhesion properties of corneal collagens. Heparan sulfate proteoglycans are minor components of the cornea, and are synthesized mainly by epithelial cells. The effect of injuries on proteoglycan synthesis is discussed.
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Affiliation(s)
- Y M Michelacci
- Departamento de Bioquímica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil.
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Berto AGA, Sampaio LO, Franco CRC, Cesar RM, Michelacci YM. A comparative analysis of structure and spatial distribution of decorin in human leiomyoma and normal myometrium. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1619:98-112. [PMID: 12495820 DOI: 10.1016/s0304-4165(02)00446-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Leiomyoma is a benign smooth muscle tumor of the uterus that affects many women in active reproductive life. It is composed by bundles of smooth muscle cells surrounded by extracellular matrix. We have recently shown that the glycosylation of extracellular matrix proteoglycans is modified in leiomyoma: increased amounts of galactosaminoglycans with structural modifications are present. The data here presented show that decorin is present in both normal myometrium and leiomyoma but tumoral decorin is glycosylated with longer galactosaminoglycan side chains. Furthermore, these chains contain a higher ratio D-glucuronate/L-iduronate, as compared to normal tissue. To determine if these changes in proteoglycan glycosylation correlates with modifications in the extracellular matrix organization, we compared the general structural architecture of leiomyoma to normal myometrium. By histochemical and immunofluorescence methods, we found a reorganization of muscle fibers and extracellular matrix, with changes in the distribution of glycoproteins, proteoglycans, and collagen. Thin reticular fibers, possibly composed by types I and III collagen, were replaced by thick fibers, possibly richer in type I collagen. Type I collagen colocalized with decorin both in leiomyoma and normal myometrium, in contrast to type IV collagen that did not. The relative amount of decorin was increased and the distribution of decorin and collagen was totally modified in the tumor, as compared to the normal myometrium. These findings reveal that not only decorin structure is modified in leiomyoma but also the tissue architecture changed, especially concerning extracellular matrix.
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Affiliation(s)
- Alessandra G A Berto
- Disciplina de Biologia Molecular, Departamento de Bioquímica, Universidade Federal de São Paulo/Escola Paulista de Medicina (UNIFESP/EPM), Brazil
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Plaas AH, West LA, Thonar EJ, Karcioglu ZA, Smith CJ, Klintworth GK, Hascall VC. Altered fine structures of corneal and skeletal keratan sulfate and chondroitin/dermatan sulfate in macular corneal dystrophy. J Biol Chem 2001; 276:39788-96. [PMID: 11514545 DOI: 10.1074/jbc.m103227200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The content and fine structure of keratan and chondroitin/dermatan sulfate in normal human corneas and corneas affected by macular corneal dystrophies (MCD) types I and II were examined by fluorophore-assisted carbohydrate electrophoresis. Normal tissues (n = 11) contained 15 microg of keratan sulfate and 8 microg of chondroitin/dermatan sulfate per mg dry weight. Keratan sulfates consisted of approximately 4% unsulfated, 42% monosulfated, and 54% disulfated disaccharides with number of average chain lengths of approximately 14 disaccharides. Chondroitin/dermatan sulfates were significantly longer, approximately 40 disaccharides per chain, and consisted of approximately 64% unsulfated, 28% 4-sulfated, and 8% 6-sulfated disaccharides. The fine structural parameters were altered in all diseased tissues. Keratan sulfate chain size was reduced to 3-4 disaccharides; chain sulfation was absent in MCD type I corneas and cartilages, and sulfation of both GlcNAc and Gal was significantly reduced in MCD type II. Chondroitin/dermatan sulfate chain sizes were also decreased in all diseased corneas to approximately 15 disaccharides, and the contents of 4- and 6-sulfated disaccharides were proportionally increased. Tissue concentrations (nanomole of chains per mg dry weight) of all glycosaminoglycan types were affected in the disease types. Keratan sulfate chain concentrations were reduced by approximately 24 and approximately 75% in type I corneas and cartilages, respectively, and by approximately 50% in type II corneas. Conversely, chondroitin/dermatan sulfate chain concentrations were increased by 60-70% in types I and II corneas. Such changes imply a modified tissue content of individual proteoglycans and/or an altered efficiency of chain substitution on the core proteins. Together with the finding that hyaluronan, not normally present in healthy adult corneas, was also detected in both disease subtypes, the data support the conclusion that a wide range of keratocyte-specific proteoglycan and glycosaminoglycan remodeling processes are activated during degeneration of the stromal matrix in the macular corneal dystrophies.
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Affiliation(s)
- A H Plaas
- Shriners Hospital for Children, 12502 N. Pine Drive, Tampa, FL 33612, USA.
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Soriano ES, Campos MS, Aguiar JA, Michelacci YM. Effect of epithelial debridement on human cornea proteoglycans. Braz J Med Biol Res 2001; 34:325-31. [PMID: 11262582 DOI: 10.1590/s0100-879x2001000300005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Corneal transparency is attributed to the regular spacing and diameter of collagen fibrils, and proteoglycans may play a role in fibrillogenesis and matrix assembly. Corneal scar tissue is opaque and this opacity is explained by decreased ultrastructural order that may be related to proteoglycan composition. Thus, the objectives of the present study were to characterize the proteoglycans synthesized by human corneal explants and to investigate the effect of mechanical epithelial debridement. Human corneas unsuitable for transplants were immersed in F-12 culture medium and maintained under tissue culture conditions. The proteoglycans synthesized in 24 h were labeled metabolically by the addition of (35)S-sulfate to the medium. These compounds were extracted by 4 M GuHCl and identified by a combination of agarose gel electrophoresis, enzymatic degradation with protease and mucopolysaccharidases, and immunoblotting. Decorin was identified as the main dermatan sulfate proteoglycan and keratan sulfate proteoglycans were also prominent components. When the glycosaminoglycan side chains were analyzed, only keratan sulfate and dermatan sulfate were detected (approximately 50% each). Nevertheless, when these compounds were (35)S-labeled metabolically, the label in dermatan sulfate was greater than in keratan sulfate, suggesting a lower synthesis rate for keratan sulfate. (35)S-Heparan sulfate also appeared. The removal of the epithelial layer caused a decrease in heparan sulfate labeling and induced the synthesis of dermatan sulfate by the stroma. The increased deposit of dermatan sulfate proteoglycans in the stroma suggests a functional relationship between epithelium and stroma that could be related to the corneal opacity that may appear after epithelial cell debridement.
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Affiliation(s)
- E S Soriano
- Departamento de Bioquímica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brasil
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