1
|
Alvarez-Rodrigo I, Willnow D, Vincent JP. The logistics of Wnt production and delivery. Curr Top Dev Biol 2023; 153:1-60. [PMID: 36967191 DOI: 10.1016/bs.ctdb.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Wnts are secreted proteins that control stem cell maintenance, cell fate decisions, and growth during development and adult homeostasis. Wnts carry a post-translational modification not seen in any other secreted protein: during biosynthesis, they are appended with a palmitoleoyl moiety that is required for signaling but also impairs solubility and hence diffusion in the extracellular space. In some contexts, Wnts act only in a juxtacrine manner but there are also instances of long range action. Several proteins and processes ensure that active Wnts reach the appropriate target cells. Some, like Porcupine, Wntless, and Notum are dedicated to Wnt function; we describe their activities in molecular detail. We also outline how the cell infrastructure (secretory, endocytic, and retromer pathways) contribute to the progression of Wnts from production to delivery. We then address how Wnts spread in the extracellular space and form a signaling gradient despite carrying a hydrophobic moiety. We highlight particularly the role of lipid-binding Wnt interactors and heparan sulfate proteoglycans. Finally, we briefly discuss how evolution might have led to the emergence of this unusual signaling pathway.
Collapse
|
2
|
Mizumoto S, Yamada S. An Overview of in vivo Functions of Chondroitin Sulfate and Dermatan Sulfate Revealed by Their Deficient Mice. Front Cell Dev Biol 2021; 9:764781. [PMID: 34901009 PMCID: PMC8652114 DOI: 10.3389/fcell.2021.764781] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/09/2021] [Indexed: 12/20/2022] Open
Abstract
Chondroitin sulfate (CS), dermatan sulfate (DS) and heparan sulfate (HS) are covalently attached to specific core proteins to form proteoglycans in their biosynthetic pathways. They are constructed through the stepwise addition of respective monosaccharides by various glycosyltransferases and maturated by epimerases as well as sulfotransferases. Structural diversities of CS/DS and HS are essential for their various biological activities including cell signaling, cell proliferation, tissue morphogenesis, and interactions with a variety of growth factors as well as cytokines. Studies using mice deficient in enzymes responsible for the biosynthesis of the CS/DS and HS chains of proteoglycans have demonstrated their essential functions. Chondroitin synthase 1-deficient mice are viable, but exhibit chondrodysplasia, progression of the bifurcation of digits, delayed endochondral ossification, and reduced bone density. DS-epimerase 1-deficient mice show thicker collagen fibrils in the dermis and hypodermis, and spina bifida. These observations suggest that CS/DS are essential for skeletal development as well as the assembly of collagen fibrils in the skin, and that their respective knockout mice can be utilized as models for human genetic disorders with mutations in chondroitin synthase 1 and DS-epimerase 1. This review provides a comprehensive overview of mice deficient in CS/DS biosyntheses.
Collapse
Affiliation(s)
- Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| |
Collapse
|
3
|
Dubail J, Cormier-Daire V. Chondrodysplasias With Multiple Dislocations Caused by Defects in Glycosaminoglycan Synthesis. Front Genet 2021; 12:642097. [PMID: 34220933 PMCID: PMC8242584 DOI: 10.3389/fgene.2021.642097] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 05/04/2021] [Indexed: 11/13/2022] Open
Abstract
Chondrodysplasias with multiple dislocations form a group of severe disorders characterized by joint laxity and multiple dislocations, severe short stature of pre- and post-natal onset, hand anomalies, and/or vertebral anomalies. The majority of chondrodysplasias with multiple dislocations have been associated with mutations in genes encoding glycosyltransferases, sulfotransferases, and transporters implicated in the synthesis or sulfation of glycosaminoglycans, long and unbranched polysaccharides composed of repeated disaccharide bond to protein core of proteoglycan. Glycosaminoglycan biosynthesis is a tightly regulated process that occurs mainly in the Golgi and that requires the coordinated action of numerous enzymes and transporters as well as an adequate Golgi environment. Any disturbances of this chain of reactions will lead to the incapacity of a cell to construct correct glycanic chains. This review focuses on genetic and glycobiological studies of chondrodysplasias with multiple dislocations associated with glycosaminoglycan biosynthesis defects and related animal models. Strong comprehension of the molecular mechanisms leading to those disorders, mostly through extensive phenotypic analyses of in vitro and/or in vivo models, is essential for the development of novel biomarkers for clinical screenings and innovative therapeutics for these diseases.
Collapse
Affiliation(s)
- Johanne Dubail
- Université de Paris, INSERM UMR 1163, Institut Imagine, Paris, France
| | - Valérie Cormier-Daire
- Université de Paris, INSERM UMR 1163, Institut Imagine, Paris, France.,Service de Génétique Clinique, Centre de Référence Pour Les Maladies Osseuses Constitutionnelles, AP-HP, Hôpital Necker-Enfants Malades, Paris, France
| |
Collapse
|
4
|
Ferencz B, Condac E, Poudel N, Munteanu MC, Sivasami P, Choudhury B, Naidu NN, Zhang F, Breshears M, Linhardt RJ, Hinsdale ME. Xylosyltransferase 2 deficiency and organ homeostasis. Glycoconj J 2020; 37:755-765. [PMID: 32965647 PMCID: PMC9248025 DOI: 10.1007/s10719-020-09945-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 08/13/2020] [Accepted: 09/04/2020] [Indexed: 12/19/2022]
Abstract
In this paper we characterize the function of Xylosyltransferase 2 (XylT2) in different tissues to investigate the role XylT2 has in the proteoglycan (PG) biochemistry of multiple organs. The results show that in all organs examined there is a widespread and significant decrease in total XylT activity in Xylt2 knock out mice (Xylt2-/-). This decrease results in increased organ weight differences in lung, heart, and spleen. These findings, in addition to our previous findings of increased liver and kidney weight with loss of serum XylT activity, suggest systemic changes in organ function due to loss of XylT2 activity. The Xylt2-/- mice have splenomegaly due to enlargement of the red pulp area and enhanced pulmonary response to bacterial liposaccharide. Tissue glycosaminoglycan composition changes are also found. These results demonstrate a role of XylT2 activity in multiple organs and their PG content. Because the residual XylT activity in the Xylt2-/- is due to xylosyltransferase 1 (XylT1), these studies indicate that both XylT1 and XylT2 have important roles in PG biosynthesis and organ homeostasis.
Collapse
Affiliation(s)
- Beatrix Ferencz
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Eduard Condac
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Nabin Poudel
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | | | - Pulavendran Sivasami
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Biswa Choudhury
- Glycotechnology Core Lab, Cellular and Molecular Medicine East, University of California, San Diego, La Jolla, CA, 92093-0687, USA
| | | | - Fuming Zhang
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180-3590, USA
| | - Melanie Breshears
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Robert J Linhardt
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180-3590, USA
| | - Myron E Hinsdale
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA.
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
| |
Collapse
|
5
|
Xiong A, Spyrou A, Forsberg-Nilsson K. Involvement of Heparan Sulfate and Heparanase in Neural Development and Pathogenesis of Brain Tumors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1221:365-403. [PMID: 32274718 DOI: 10.1007/978-3-030-34521-1_14] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Brain tumors are aggressive and devastating diseases. The most common type of brain tumor, glioblastoma (GBM), is incurable and has one of the worst five-year survival rates of all human cancers. GBMs are invasive and infiltrate healthy brain tissue, which is one main reason they remain fatal despite resection, since cells that have already migrated away lead to rapid regrowth of the tumor. Curative therapy for medulloblastoma (MB), the most common pediatric brain tumor, has improved, but the outcome is still poor for many patients, and treatment causes long-term complications. Recent advances in the classification of pediatric brain tumors reveal distinct subgroups, allowing more targeted therapy for the most aggressive forms, and sparing children with less malignant tumors the side-effects of massive treatment. Heparan sulfate proteoglycans (HSPGs), main components of the neurogenic niche, interact specifically with a large number of physiologically important molecules and vital roles for HS biosynthesis and degradation in neural stem cell differentiation have been presented. HSPGs are composed of a core protein with attached highly charged, sulfated disaccharide chains. The major enzyme that degrades HS is heparanase (HPSE), an important regulator of extracellular matrix (ECM) remodeling which has been suggested to promote the growth and invasion of other types of tumors. This is of clinical interest because GBM are highly invasive and children with metastatic MB at the time of diagnosis exhibit a worse outcome. Here we review the involvement of HS and HPSE in development of the nervous system and some of its most malignant brain tumors, glioblastoma and medulloblastoma.
Collapse
Affiliation(s)
- Anqi Xiong
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
- Department of Medical Biochemistry and Biophysics, Karolinska Insitutet, Stockholm, Sweden
| | - Argyris Spyrou
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Karin Forsberg-Nilsson
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
| |
Collapse
|
6
|
Guleray N, Simsek Kiper PO, Utine GE, Boduroglu K, Alikasifoglu M. Intrafamilial variability of XYLT2-related spondyloocular syndrome. Eur J Med Genet 2019; 62:103585. [PMID: 30496831 DOI: 10.1016/j.ejmg.2018.11.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/07/2018] [Accepted: 11/22/2018] [Indexed: 12/19/2022]
Abstract
Spondyloocular syndrome is characterized by generalized osteoporosis, multiple fractures and severe ocular findings. The causative XYLT2 mutations have recently been identified with the use of whole exome sequencing. We report on two siblings with spondyloocular syndrome who presented with varying clinical severity. A novel XYLT2 missense mutation was detected in a region evolutionary conserved across the species. This report along with the previous reports demonstrates that variable expressivity may be possible even within the same family. These two siblings with a novel mutation further expand the clinical and mutational spectrum of spondyloocular syndrome.
Collapse
Affiliation(s)
- Naz Guleray
- Department of Medical Genetics, Hacettepe University Faculty of Medicine, Ankara, Turkey.
| | - Pelin Ozlem Simsek Kiper
- Division of Pediatric Genetics, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Gulen Eda Utine
- Division of Pediatric Genetics, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Koray Boduroglu
- Department of Medical Genetics, Hacettepe University Faculty of Medicine, Ankara, Turkey; Division of Pediatric Genetics, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Mehmet Alikasifoglu
- Department of Medical Genetics, Hacettepe University Faculty of Medicine, Ankara, Turkey; Division of Pediatric Genetics, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| |
Collapse
|
7
|
Sivasami P, Poudel N, Munteanu MC, Hudson J, Lovern P, Liu L, Griffin T, Hinsdale ME. Adipose tissue loss and lipodystrophy in xylosyltransferase II deficient mice. Int J Obes (Lond) 2019; 43:1783-1794. [PMID: 30778123 PMCID: PMC7067554 DOI: 10.1038/s41366-019-0324-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 10/21/2018] [Accepted: 11/22/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND/OBJECTIVES The cellular and extracellular matrix (ECM) interactions that regulate adipose tissue homeostasis are incompletely understood. Proteoglycans (PGs) and their sulfated glycosaminoglycans (GAGs) provide spatial and temporal signals for ECM organization and interactions with resident cells by impacting growth factor and cytokine activity. Therefore, PGs and their GAGs could be significant to adipose tissue homeostasis. The purpose of this study was to determine the role of ECM sulfated GAGs in adipose tissue homeostasis. METHODS Adipose tissue and metabolic homeostasis in mice deficient in xylosyltransferase 2 (Xylt2-/-) were examined by histologic analyses, gene expression analyses, whole body fat composition measurements, and glucose tolerance test. Adipose tissue inflammation and adipocyte precursors were characterized by flow cytometry and in vitro culture of mesenchymal stem cells. RESULTS Xylt2-/- mice have low body weight due to overall reductions in abdominal fat deposition. Histologically, the adipocytes are reduced in size and number in both gonadal and mesenteric fat depots of Xylt2-/- mice. In addition, these mice are glucose intolerant, insulin resistant, and have increased serum triglycerides as compared to Xylt2 + / + control mice. Furthermore, the adipose tissue niche has increased inflammatory cells and enrichment of proinflammatory factors IL6 and IL1β, and these mice also have a loss of adipose tissue vascular endothelial cells. Lastly, xylosyltransferease-2 (XylT2) deficient mesenchymal stem cells from gonadal adipose tissue and bone marrow exhibit impaired adipogenic differentiation in vitro. CONCLUSIONS Decreased GAGs due to the loss of the key GAG assembly enzyme XylT2 causes reduced steady state adipose tissue stores leading to a unique lipodystrophic model. Accumulation of an adipocytic precursor pool of cells is discovered indicating an interruption in differentiation. Therefore, adipose tissue GAGs are important in the homeostasis of adipose tissue by mediating control of adipose precursor development, tissue inflammation, and vascular development.
Collapse
Affiliation(s)
- Pulavendran Sivasami
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Nabin Poudel
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | | | - Joanna Hudson
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Pamela Lovern
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Lin Liu
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Tim Griffin
- Aging and Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Myron E Hinsdale
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK, 74078, USA.
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
| |
Collapse
|
8
|
Paganini C, Costantini R, Superti-Furga A, Rossi A. Bone and connective tissue disorders caused by defects in glycosaminoglycan biosynthesis: a panoramic view. FEBS J 2019; 286:3008-3032. [PMID: 31286677 DOI: 10.1111/febs.14984] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 05/22/2019] [Accepted: 07/04/2019] [Indexed: 02/06/2023]
Abstract
Glycosaminoglycans (GAGs) are a heterogeneous family of linear polysaccharides that constitute the carbohydrate moiety covalently attached to the protein core of proteoglycans, macromolecules present on the cell surface and in the extracellular matrix. Several genetic disorders of bone and connective tissue are caused by mutations in genes encoding for glycosyltransferases, sulfotransferases and transporters that are responsible for the synthesis of sulfated GAGs. Phenotypically, these disorders all reflect alterations in crucial biological functions of GAGs in the development, growth and homoeostasis of cartilage and bone. To date, up to 27 different skeletal phenotypes have been linked to mutations in 23 genes encoding for proteins involved in GAG biosynthesis. This review focuses on recent genetic, molecular and biochemical studies of bone and connective tissue disorders caused by GAG synthesis defects. These insights and future research in the field will provide a deeper understanding of the molecular pathogenesis of these disorders and will pave the way for developing common therapeutic strategies that might be targeted to a range of individual phenotypes.
Collapse
Affiliation(s)
- Chiara Paganini
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Italy
| | - Rossella Costantini
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Italy
| | - Andrea Superti-Furga
- Division of Genetic Medicine, Lausanne University Hospital, University of Lausanne, Switzerland
| | - Antonio Rossi
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Italy
| |
Collapse
|
9
|
Briggs DC, Hohenester E. Structural Basis for the Initiation of Glycosaminoglycan Biosynthesis by Human Xylosyltransferase 1. Structure 2018; 26:801-809.e3. [PMID: 29681470 PMCID: PMC5992326 DOI: 10.1016/j.str.2018.03.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/15/2018] [Accepted: 03/20/2018] [Indexed: 01/10/2023]
Abstract
Proteoglycans (PGs) are essential components of the animal extracellular matrix and are required for cell adhesion, migration, signaling, and immune function. PGs are composed of a core protein and long glycosaminoglycan (GAG) chains, which often specify PG function. GAG biosynthesis is initiated by peptide O-xylosyltransferases, which transfer xylose onto selected serine residues in the core proteins. We have determined crystal structures of human xylosyltransferase 1 (XT1) in complex with the sugar donor, UDP-xylose, and various acceptor peptides. The structures reveal unique active-site features that, in conjunction with functional experiments, explain the substrate specificity of XT1. A constriction within the peptide binding cleft requires the acceptor serine to be followed by glycine or alanine. The remainder of the cleft can accommodate a wide variety of sequences, but with a general preference for acidic residues. These findings provide a framework for understanding the selectivity of GAG attachment.
Collapse
Affiliation(s)
- David C Briggs
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
| | - Erhard Hohenester
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK.
| |
Collapse
|
10
|
Umair M, Eckstein G, Rudolph G, Strom T, Graf E, Hendig D, Hoover J, Alanay J, Meitinger T, Schmidt H, Ahmad W. Homozygous XYLT2 variants as a cause of spondyloocular syndrome. Clin Genet 2018; 93:913-918. [PMID: 29136277 DOI: 10.1111/cge.13179] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/27/2017] [Accepted: 10/29/2017] [Indexed: 12/20/2022]
Abstract
Spondyloocular syndrome (SOS) is a rare autosomal recessive, skeletal disorder. Two recent studies have shown that it is the result of biallelic sequence variants in the XYLT2 gene with pleiotropic effects in multiple organs, including retina, heart muscle, inner ear, cartilage, and bone. The XYLT2 gene encodes xylosyltransferase 2, which catalyzes the transfer of xylose (monosaccharide) to the core protein of proteoglycans (PGs) leading to initiating the process of PG assembly. SOS was originally characterized in 2 families A and B of Iraqi and Turkish origin, respectively. Using DNA from affected members of the same 2 families, we performed whole exome sequencing, which revealed 2 novel homozygous missense variants (c.1159C > T, p.Arg387Trp) and (c.2548G > C, p.Asp850His). Our findings extend the body of evidence that SOS is caused by homozygous variants in the XYLT2 gene. In addition, this report has extended the phenotypic description of SOS by adding follow-up data from 5 affected individuals in one of the two families, presented here.
Collapse
Affiliation(s)
- M Umair
- Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
- Institute of Human Genetics, Technische Universitat, Munchen, Germany
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - G Eckstein
- Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
| | - G Rudolph
- University Eye Hospital, Ludwig Maximilians University, Munich, Germany
| | - T Strom
- Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
| | - E Graf
- Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
| | - D Hendig
- Institute for Laboratory and Transfusion Medicine, Heart and Diabetes, Center North Rhine-Westphalia, University Hospital of the Ruhr University, Ruhr, Germany
| | - J Hoover
- University Children's Hospital, Division of Endocrinology and Diabetology, Munich, Germany
| | - J Alanay
- Institute of Human Genetics, Technische Universitat, Munchen, Germany
| | - T Meitinger
- Institute of Human Genetics, Helmholtz Zentrum Munchen, Neuherberg, Germany
- Institute of Human Genetics, Technische Universitat, Munchen, Germany
| | - H Schmidt
- University Eye Hospital, Ludwig Maximilians University, Munich, Germany
| | - W Ahmad
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| |
Collapse
|
11
|
Six2creFrs2α knockout mice are a novel model of renal cystogenesis. Sci Rep 2016; 6:36736. [PMID: 27853247 PMCID: PMC5113122 DOI: 10.1038/srep36736] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 10/14/2016] [Indexed: 01/06/2023] Open
Abstract
Six2cre-mediated deletion of Frs2α (Six2creFrs2αKO), a major fibroblast growth factor receptor (Fgfr) docking protein in mouse nephron progenitors results in perinatal renal hypoplasia; however, postnatal Six2creFrs2αKO kidneys develop cysts. We sought to determine the pathogenesis of Six2creFrs2αKO cyst formation. We performed histological assays, Western blots, and quantitative PCR (qPCR). While embryonic day (E) 18.5 Six2Frs2αKO kidneys were hypoplastic and not cystic, postnatal day (P) 7 mutants had proximal tubular-derived cysts that nearly replaced the renal parenchyma by P21. Mutants had high proximal tubular proliferation rates and interstitial fibrosis, similar to known polycystic kidney disease (PKD) models. Six2creFrs2αKO kidneys also had upregulation of Wnt/βcatenin signaling, macrophage infiltration and chemokine production (e.g. ectopic Ccl2 in non-dilated proximal tubules), and augmented hedgehog signaling, features also seen in other PKD models. We saw increased Gli1 (hedgehog readout) in postnatal Six2creFrs2αKO interstitium and ectopic sonic hedgehog (Shh) in subsets of non-dilated P7 mutant proximal tubules (likely driving the stromal Gli expression). As ectopic tubular Shh and Ccl2 expression is seen after acute kidney injury (AKI), we interrogated another bone fide AKI marker, Kim1 and noted ectopic expression in P7 non-dilated proximal tubules. These observations suggest that aberrantly activated “AKI” pathways may drive pathogenesis in PKD.
Collapse
|
12
|
Li JP, Kusche-Gullberg M. Heparan Sulfate: Biosynthesis, Structure, and Function. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 325:215-73. [PMID: 27241222 DOI: 10.1016/bs.ircmb.2016.02.009] [Citation(s) in RCA: 182] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Heparan sulfate (HS) proteoglycans (PGs) are ubiquitously expressed on cell surfaces and in the extracellular matrix of most animal tissues, having essential functions in development and homeostasis, as well as playing various roles in disease processes. The functions of HSPGs are mainly dependent on interactions between the HS-side chains with a variety of proteins including cytokines, growth factors, and their receptors. In a given HS polysaccharide, negatively charged sulfate and carboxylate groups are arranged in various types of domains, generated through strictly regulated biosynthetic reactions and with enormous potential for structural variability. The mode of HS-protein interactions is assessed through binding experiments using saccharides of defined composition in vitro, signaling assays in cell models where HS structures are manipulated, and targeted disruption of genes for biosynthetic enzymes in animals (mouse, zebrafish, Drosophila, and Caenorhabditis elegans) followed by phenotype analysis. Whereas some protein ligands appear to require strictly defined HS structure, others bind to variable saccharide domains without apparent dependence on distinct saccharide sequence. These findings raise intriguing questions concerning the functional significance of regulation in HS biosynthesis and the potential for development of therapeutics targeting HS-protein interactions.
Collapse
Affiliation(s)
- J-P Li
- Department of Medical Biochemistry and Microbiology, University of Uppsala, Uppsala, Sweden; SciLifeLab, University of Uppsala, Uppsala, Sweden.
| | | |
Collapse
|
13
|
Pintaudi M, Veneselli E, Voci A, Vignoli A, Castiglione D, Calevo MG, Grasselli E, Ragazzoni M, Cogliati F, Calzari L, Scornavacca GF, Russo S, Vergani L. Blood oxidative stress and metallothionein expression in Rett syndrome: Probing for markers. World J Biol Psychiatry 2016; 17:198-209. [PMID: 26469135 DOI: 10.3109/15622975.2015.1077990] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Oxidative stress seems to be involved in Rett syndrome (RTT). The aim of this study was to assess the antioxidant status in RTT children with MECP2 gene mutations with respect to healthy controls, and to explore novel blood antioxidant markers for RTT severity. METHODS In erythrocytes from RTT females aged 2-14 years (n = 27) and age-matched controls (n = 27), we measured the levels of malonaldehyde and the activity of two antioxidant enzymes, Cu/Zn-superoxide dismutase and catalase, by spectrophotometric assays. In leukocytes, the expression of metallothioneins, the main non-enzymatic antioxidants, was assessed by real-time RT-PCR. In nine selected RTT children, methylome analysis was also performed. RESULTS Blood of RTT patients showed increased lipid peroxidation and a dysregulated pattern of MT expression, while enzymatic activities did not change significantly with respect to controls. Moreover, we observed no epigenetic dysregulation in CpG-enriched promoter regions of the analysed genes but significant hypomethylation in the random loci. CONCLUSIONS As the haematic level of MT-1A directly correlates with the phenotype severity, this metallothionein can represent a marker for RTT severity. Moreover, the attempt to link the level of blood oxidative stress with MECP2 mutation and specific clinical features led us to draw some interesting conclusions.
Collapse
Affiliation(s)
- Maria Pintaudi
- a DINOGMI, Dipartimento Di Neuroscienze , Riabilitazione, Oftalmologia, Genetica E Scienze Materno-Infantili, Università Di Genova , Genova , Italy .,b Unità Di Neuropsichiatria Infantile, Istituto Giannina Gaslini , Genova , Italy
| | - Edvige Veneselli
- a DINOGMI, Dipartimento Di Neuroscienze , Riabilitazione, Oftalmologia, Genetica E Scienze Materno-Infantili, Università Di Genova , Genova , Italy .,b Unità Di Neuropsichiatria Infantile, Istituto Giannina Gaslini , Genova , Italy
| | - Adriana Voci
- c DISTAV, Dipartimento Di Scienze Della Terra , Dell'ambiente E Della Vita, Università Di Genova , Genova , Italy
| | - Aglaia Vignoli
- d Centro Epilessia, Azienda Ospedaliera San Paolo, Dipartimento Di Scienze Della Salute , Università Degli Studi Di Milano , Milano , Italy
| | | | - Maria Grazia Calevo
- b Unità Di Neuropsichiatria Infantile, Istituto Giannina Gaslini , Genova , Italy .,f Unità Di Epidemiologia E Biostatistica, Istituto Giannina Gaslini , Genova , Italy , and
| | - Elena Grasselli
- c DISTAV, Dipartimento Di Scienze Della Terra , Dell'ambiente E Della Vita, Università Di Genova , Genova , Italy
| | - Milena Ragazzoni
- c DISTAV, Dipartimento Di Scienze Della Terra , Dell'ambiente E Della Vita, Università Di Genova , Genova , Italy
| | - Francesca Cogliati
- g Laboratorio Di Citogenetica E Genetica Molecolare, I.R.C.C.S. Istituto Auxologico Italiano , Milano
| | - Luciano Calzari
- g Laboratorio Di Citogenetica E Genetica Molecolare, I.R.C.C.S. Istituto Auxologico Italiano , Milano
| | - Giulia Federica Scornavacca
- d Centro Epilessia, Azienda Ospedaliera San Paolo, Dipartimento Di Scienze Della Salute , Università Degli Studi Di Milano , Milano , Italy
| | - Silvia Russo
- g Laboratorio Di Citogenetica E Genetica Molecolare, I.R.C.C.S. Istituto Auxologico Italiano , Milano
| | - Laura Vergani
- c DISTAV, Dipartimento Di Scienze Della Terra , Dell'ambiente E Della Vita, Università Di Genova , Genova , Italy
| |
Collapse
|
14
|
Munns CF, Fahiminiya S, Poudel N, Munteanu MC, Majewski J, Sillence DO, Metcalf JP, Biggin A, Glorieux F, Fassier F, Rauch F, Hinsdale ME. Homozygosity for frameshift mutations in XYLT2 result in a spondylo-ocular syndrome with bone fragility, cataracts, and hearing defects. Am J Hum Genet 2015; 96:971-8. [PMID: 26027496 PMCID: PMC4457947 DOI: 10.1016/j.ajhg.2015.04.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 04/24/2015] [Indexed: 01/05/2023] Open
Abstract
Heparan and chondroitin/dermatan sulfated proteoglycans have a wide range of roles in cellular and tissue homeostasis including growth factor function, morphogen gradient formation, and co-receptor activity. Proteoglycan assembly initiates with a xylose monosaccharide covalently attached by either xylosyltransferase I or II. Three individuals from two families were found that exhibited similar phenotypes. The index case subjects were two brothers, individuals 1 and 2, who presented with osteoporosis, cataracts, sensorineural hearing loss, and mild learning defects. Whole exome sequence analyses showed that both individuals had a homozygous c.692dup mutation (GenBank: NM_022167.3) in the xylosyltransferase II locus (XYLT2) (MIM: 608125), causing reduced XYLT2 mRNA and low circulating xylosyltransferase (XylT) activity. In an unrelated boy (individual 3) from the second family, we noted low serum XylT activity. Sanger sequencing of XYLT2 in this individual revealed a c.520del mutation in exon 2 that resulted in a frameshift and premature stop codon (p.Ala174Profs(∗)35). Fibroblasts from individuals 1 and 2 showed a range of defects including reduced XylT activity, GAG incorporation of (35)SO4, and heparan sulfate proteoglycan assembly. These studies demonstrate that human XylT2 deficiency results in vertebral compression fractures, sensorineural hearing loss, eye defects, and heart defects, a phenotype that is similar to the autosomal-recessive disorder spondylo-ocular syndrome of unknown cause. This phenotype is different from what has been reported in individuals with other linker enzyme deficiencies. These studies illustrate that the cells of the lens, retina, heart muscle, inner ear, and bone are dependent on XylT2 for proteoglycan assembly in humans.
Collapse
Affiliation(s)
- Craig F Munns
- Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia
| | - Somayyeh Fahiminiya
- Department of Human Genetics, Faculty of Medicine, McGill University and Genome Quebec Innovation Center, Montréal, QC H3A 1B1, Canada
| | - Nabin Poudel
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | | | - Jacek Majewski
- Department of Human Genetics, Faculty of Medicine, McGill University and Genome Quebec Innovation Center, Montréal, QC H3A 1B1, Canada
| | - David O Sillence
- Discipline of Genetic Medicine, The Children's Hospital at Westmead Clinical School, Sydney Medicine, Westmead, NSW 2145, Australia
| | - Jordan P Metcalf
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73126, USA
| | - Andrew Biggin
- Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia
| | | | | | - Frank Rauch
- Shriners Hospital for Children, Montréal, QC H3G 1A6, Canada
| | - Myron E Hinsdale
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA; Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73126, USA.
| |
Collapse
|
15
|
Kuhn J, Götting C, Beahm BJ, Bertozzi CR, Faust I, Kuzaj P, Knabbe C, Hendig D. Xylosyltransferase II is the predominant isoenzyme which is responsible for the steady-state level of xylosyltransferase activity in human serum. Biochem Biophys Res Commun 2015; 459:469-74. [PMID: 25748573 PMCID: PMC6598695 DOI: 10.1016/j.bbrc.2015.02.129] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 02/22/2015] [Indexed: 01/13/2023]
Abstract
In mammals, two active xylosyltransferase isoenzymes (EC 2.4.2.16) exist. Both xylosyltransferases I and II (XT-I and XT-II) catalyze the transfer of xylose from UDP-xylose to select serine residues in the proteoglycan core protein. Altered XT activity in human serum was found to correlate directly with various diseases such as osteoarthritis, systemic sclerosis, liver fibrosis, and pseudoxanthoma elasticum. To interpret the significance of the enzyme activity alteration observed in disease states it is important to know which isoenzyme is responsible for the XT activity in serum. Until now it was impossible for a specific measurement of XT-I or XT-II activity, respectively, because of the absence of a suitable enzyme substrate. This issue has now been solved and the following experimental study demonstrates for the first time, via the enzyme activity that XT-II is the predominant isoenzyme responsible for XT activity in human serum. The proof was performed using natural UDP-xylose as the xylose donor, as well as the artificial compound UDP-4-azido-4-deoxyxylose, which is a selective xylose donor for XT-I.
Collapse
Affiliation(s)
- Joachim Kuhn
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Georgstraße 11, 32545 Bad Oeynhausen, Germany.
| | - Christian Götting
- MVZ Labor Limbach Nürnberg, Lina-Ammon-Strasse 28, 90471 Nürnberg, Germany
| | - Brendan J Beahm
- Department of Chemistry and Molecular and Cell Biology Howard Hughes Medical Institute University of California, Berkeley, CA 94720, USA
| | - Carolyn R Bertozzi
- Department of Chemistry and Molecular and Cell Biology Howard Hughes Medical Institute University of California, Berkeley, CA 94720, USA
| | - Isabel Faust
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Georgstraße 11, 32545 Bad Oeynhausen, Germany
| | - Patricia Kuzaj
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Georgstraße 11, 32545 Bad Oeynhausen, Germany
| | - Cornelius Knabbe
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Georgstraße 11, 32545 Bad Oeynhausen, Germany
| | - Doris Hendig
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Georgstraße 11, 32545 Bad Oeynhausen, Germany
| |
Collapse
|
16
|
Xiong A, Kundu S, Forsberg-Nilsson K. Heparan sulfate in the regulation of neural differentiation and glioma development. FEBS J 2014; 281:4993-5008. [DOI: 10.1111/febs.13097] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 09/17/2014] [Accepted: 10/02/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Anqi Xiong
- Department of Immunology, Genetics and Pathology, and Science for Life Laboratory; Rudbeck Laboratory; Uppsala University; Uppsala Sweden
| | - Soumi Kundu
- Department of Immunology, Genetics and Pathology, and Science for Life Laboratory; Rudbeck Laboratory; Uppsala University; Uppsala Sweden
| | - Karin Forsberg-Nilsson
- Department of Immunology, Genetics and Pathology, and Science for Life Laboratory; Rudbeck Laboratory; Uppsala University; Uppsala Sweden
| |
Collapse
|
17
|
Lee K, Boctor S, Barisoni LMC, Gusella GL. Inactivation of integrin-β1 prevents the development of polycystic kidney disease after the loss of polycystin-1. J Am Soc Nephrol 2014; 26:888-95. [PMID: 25145933 DOI: 10.1681/asn.2013111179] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Dysregulation of polycystin-1 (PC1) leads to autosomal dominant polycystic kidney disease (ADPKD), a disorder characterized by the formation of multiple bilateral renal cysts, the progressive accumulation of extracellular matrix (ECM), and the development of tubulointerstitial fibrosis. Correspondingly, cystic epithelia express higher levels of integrins (ECM receptors that control various cellular responses, such as cell proliferation, migration, and survival) that are characteristically altered in cystic cells. To determine whether the altered expression of ECM and integrins could establish a pathologic autostimulatory loop, we tested the role of integrin-β1 in vitro and on the cystic development of ADPKD in vivo. Compared with wild-type cells, PC1-depleted immortalized renal collecting duct cells had higher levels of integrin-β1 and fibronectin and displayed increased integrin-mediated signaling in the presence of Mn(2+). In mice, conditional inactivation of integrin-β1 in collecting ducts resulted in a dramatic inhibition of Pkd1-dependent cystogenesis with a concomitant suppression of fibrosis and preservation of normal renal function. Our data provide genetic evidence that a functional integrin-β1 is required for the early events leading to renal cystogenesis in ADPKD and suggest that the integrin signaling pathway may be an effective therapeutic target for slowing disease progression.
Collapse
Affiliation(s)
- Kyung Lee
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; and
| | - Sylvia Boctor
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; and
| | | | - G Luca Gusella
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; and
| |
Collapse
|
18
|
Mizumoto S, Yamada S, Sugahara K. Human genetic disorders and knockout mice deficient in glycosaminoglycan. BIOMED RESEARCH INTERNATIONAL 2014; 2014:495764. [PMID: 25126564 PMCID: PMC4122003 DOI: 10.1155/2014/495764] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 06/08/2014] [Indexed: 12/20/2022]
Abstract
Glycosaminoglycans (GAGs) are constructed through the stepwise addition of respective monosaccharides by various glycosyltransferases and maturated by epimerases and sulfotransferases. The structural diversity of GAG polysaccharides, including their sulfation patterns and sequential arrangements, is essential for a wide range of biological activities such as cell signaling, cell proliferation, tissue morphogenesis, and interactions with various growth factors. Studies using knockout mice of enzymes responsible for the biosynthesis of the GAG side chains of proteoglycans have revealed their physiological functions. Furthermore, mutations in the human genes encoding glycosyltransferases, sulfotransferases, and related enzymes responsible for the biosynthesis of GAGs cause a number of genetic disorders including chondrodysplasia, spondyloepiphyseal dysplasia, and Ehlers-Danlos syndromes. This review focused on the increasing number of glycobiological studies on knockout mice and genetic diseases caused by disturbances in the biosynthetic enzymes for GAGs.
Collapse
Affiliation(s)
- Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan
| | - Kazuyuki Sugahara
- Laboratory of Proteoglycan Signaling and Therapeutics, Frontier Research Center for Post-Genomic Science and Technology, Graduate School of Life Science, Hokkaido University, West-11, North-21, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
| |
Collapse
|
19
|
Wills ES, Roepman R, Drenth JPH. Polycystic liver disease: ductal plate malformation and the primary cilium. Trends Mol Med 2014; 20:261-70. [PMID: 24506938 DOI: 10.1016/j.molmed.2014.01.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 01/03/2014] [Accepted: 01/07/2014] [Indexed: 02/06/2023]
Abstract
Polycystic livers are found in autosomal dominant polycystic kidney disease (ADPKD), caused by polycystic kidney disease (PKD)1 and PKD2 mutations in virtually all cases, and in isolated polycystic liver disease (PCLD), where 20% of cases are caused by mutations in Protein kinase C substrate 80K-H (PRKCSH) or SEC63. Loss of heterozygosity in single hepatoblasts leads to underlying cystogenic ductal plate malformations. Crucially, actual components driving this development remain elusive. Recent advances have unraveled the roles of transforming growth factor (TGF)-β, Notch and Wnt signaling, transcriptional regulators such as hepatocyte nuclear factor (HNF)6 and HNF1β, as well as cilium function in hepatobiliary organogenesis. In polycystic liver disease, mutation or defective co-translational processing of key elements required for primary cilium formation have been implicated. This review recapitulates liver patterning factors in hepatobiliary development and extracts molecular players in hepatic cystogenesis.
Collapse
Affiliation(s)
- Edgar S Wills
- Department of Medicine, Division of Gastroenterology and Hepatology, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Ronald Roepman
- Department of Human Genetics, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands; Radboud Institute of Molecular Life Sciences, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Joost P H Drenth
- Department of Medicine, Division of Gastroenterology and Hepatology, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands.
| |
Collapse
|
20
|
Superina S, Borovina A, Ciruna B. Analysis of maternal-zygotic ugdh mutants reveals divergent roles for HSPGs in vertebrate embryogenesis and provides new insight into the initiation of left-right asymmetry. Dev Biol 2014; 387:154-66. [PMID: 24462977 DOI: 10.1016/j.ydbio.2014.01.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/20/2013] [Accepted: 01/14/2014] [Indexed: 11/25/2022]
Abstract
Growth factors and morphogens regulate embryonic patterning, cell fate specification, cell migration, and morphogenesis. The activity and behavior of these signaling molecules are regulated in the extracellular space through interactions with proteoglycans (Bernfield et al., 1999; Perrimon and Bernfield 2000; Lander and Selleck 2000; Selleck 2000). Proteoglycans are high molecular-weight proteins consisting of a core protein with covalently linked glycosaminoglycan (GAG) side chains, which are thought to mediate ligand interaction. Drosophila mutant embryos deficient for UDP-glucose dehydrogenase activity (Ugdh, required for GAG synthesis) exhibit abnormal Fgf, Wnt and TGFß signaling and die during gastrulation, indicating a broad and critical role for proteoglycans during early embryonic development (Lin et al., 1999; Lin and Perrimon 2000) (Hacker et al., 1997). Mouse Ugdh mutants also die at gastrulation, however, only Fgf signaling appears disrupted (Garcia-Garcia and Anderson, 2003). These findings suggested a possible divergence in the requirement for proteoglycans during Drosophila and mouse embryogenesis, and that mammals may have evolved alternative means of regulating Wnt and TGFß activity. To further examine the function of proteoglycans in vertebrate development, we have characterized zebrafish mutants devoid of both maternal and zygotic Ugdh/Jekyll activity (MZjekyll). We demonstrate that MZjekyll mutant embryos display abnormal Fgf, Shh, and Wnt signaling activities, with concomitant defects in central nervous system patterning, cardiac ventricular fate specification and axial morphogenesis. Furthermore, we uncover a novel role for proteoglycans in left-right pattern formation. Our findings resolve longstanding questions into the evolutionary conservation of Ugdh function and provide new mechanistic insights into the initiation of left-right asymmetry.
Collapse
Affiliation(s)
- Simone Superina
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ont., Canada M5G 1X8; Department of Molecular Genetics, The University of Toronto, Toronto, Ont., Canada M5S 1A8
| | - Antonia Borovina
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ont., Canada M5G 1X8; Department of Molecular Genetics, The University of Toronto, Toronto, Ont., Canada M5S 1A8
| | - Brian Ciruna
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, Ont., Canada M5G 1X8; Department of Molecular Genetics, The University of Toronto, Toronto, Ont., Canada M5S 1A8.
| |
Collapse
|
21
|
Schreml J, Durmaz B, Cogulu O, Keupp K, Beleggia F, Pohl E, Milz E, Coker M, Ucar SK, Nürnberg G, Nürnberg P, Kuhn J, Ozkinay F. The missing "link": an autosomal recessive short stature syndrome caused by a hypofunctional XYLT1 mutation. Hum Genet 2014; 133:29-39. [PMID: 23982343 DOI: 10.1007/s00439-013-1351-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 08/10/2013] [Indexed: 12/31/2022]
Abstract
Proteoglycan (PG) synthesis begins with the sequential addition of a "linker chain", made up of four sugar residues, to a specific region of a core protein. Defects in the enzymes catalyzing steps two to four of the linker chain synthesis have been shown to cause autosomal recessive human phenotypes while no mutation has yet been reported in humans for the xylosyltransferases 1 and 2 (XT1 and XT2), the initiating enzymes in the linker chain formation. Here, we present a consanguineous Turkish family with two affected individuals presenting with short stature, distinct facial features, alterations of fat distribution, and moderate intellectual disability. X-rays showed only mild skeletal changes in the form of a short femoral neck, stocky and plump long bones and thickened ribs. Using a combination of whole-exome sequencing (WES), determination of homozygous stretches by WES variants, and classical linkage analysis, we identified the homozygous missense mutation c.C1441T in XYLT1, encoding XT1, within a large homozygous stretch on chromosome 16p13.12-p12.1. The mutation co-segregated with the phenotype in the family, is not found in over 13,000 alleles in the exome variant server and is predicted to change a highly conserved arginine at position 481 (p.R481W) located in the putative catalytical domain. Immunostaining of primary patient fibroblasts showed a loss of predominance of Golgi localization in mutant cells. Moreover, western blot analysis of decorin in cell culture supernatant demonstrated glycosylation differences between patient and control cells. Our data provide evidence that functional alterations of XT1 cause an autosomal recessive short stature syndrome associated with intellectual disability.
Collapse
Affiliation(s)
- Julia Schreml
- Institute of Human Genetics, University of Cologne, Cologne, Germany,
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Mis EK, Liem KF, Kong Y, Schwartz NB, Domowicz M, Weatherbee SD. Forward genetics defines Xylt1 as a key, conserved regulator of early chondrocyte maturation and skeletal length. Dev Biol 2014; 385:67-82. [PMID: 24161523 PMCID: PMC3895954 DOI: 10.1016/j.ydbio.2013.10.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 10/11/2013] [Accepted: 10/14/2013] [Indexed: 12/12/2022]
Abstract
The long bones of the vertebrate body are built by the initial formation of a cartilage template that is later replaced by mineralized bone. The proliferation and maturation of the skeletal precursor cells (chondrocytes) within the cartilage template and their replacement by bone is a highly coordinated process which, if misregulated, can lead to a number of defects including dwarfism and other skeletal deformities. This is exemplified by the fact that abnormal bone development is one of the most common types of human birth defects. Yet, many of the factors that initiate and regulate chondrocyte maturation are not known. We identified a recessive dwarf mouse mutant (pug) from an N-ethyl-N-nitrosourea (ENU) mutagenesis screen. pug mutant skeletal elements are patterned normally during development, but display a ~20% length reduction compared to wild-type embryos. We show that the pug mutation does not lead to changes in chondrocyte proliferation but instead promotes premature maturation and early ossification, which ultimately leads to disproportionate dwarfism. Using sequence capture and high-throughput sequencing, we identified a missense mutation in the Xylosyltransferase 1 (Xylt1) gene in pug mutants. Xylosyltransferases catalyze the initial step in glycosaminoglycan (GAG) chain addition to proteoglycan core proteins, and these modifications are essential for normal proteoglycan function. We show that the pug mutation disrupts Xylt1 activity and subcellular localization, leading to a reduction in GAG chains in pug mutants. The pug mutant serves as a novel model for mammalian dwarfism and identifies a key role for proteoglycan modification in the initiation of chondrocyte maturation.
Collapse
Affiliation(s)
- Emily K. Mis
- Department of Genetics, Yale University, New Haven, CT 06520
| | - Karel F. Liem
- Department of Pediatrics, Yale University, New Haven, CT 06520
| | - Yong Kong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
- W.M. Keck Foundation Biotechnology Resource Laboratory, Yale University, New Haven, CT 06520
| | | | - Miriam Domowicz
- Department of Pediatrics, University of Chicago, Chicago, IL 60637
| | | |
Collapse
|
23
|
Müller B, Prante C, Knabbe C, Kleesiek K, Götting C. First identification and functional analysis of the human xylosyltransferase II promoter. Glycoconj J 2013; 30:237-45. [PMID: 22886070 DOI: 10.1007/s10719-012-9439-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 07/25/2012] [Accepted: 07/27/2012] [Indexed: 12/26/2022]
Abstract
Recently, we demonstrated that the human xylosyltransferase II (XT-II) has enzymatic activity and is able to catalyze the initial and rate-limiting step in the biosynthesis of glycosaminoglycans (GAGs) like chondroitin and dermatan sulfate, as well as heparan sulfate and heparin. Therefore, this enzyme also very likely assumes a crucial regulatory role in the biosynthesis of proteoglycans (PGs). In this study, we identified and characterized for the first time the XYLT2 gene promoter region and transcription factors involved in its regulation. Several binding sites for members of the Sp1 family of transcription factors were identified as being necessary for transcriptional regulation of the XYLT2 gene. This was determined by mithramycin A treatment, electrophoretic mobility shift and supershift assays, as well as numerous site-directed mutagenesis experiments. Different 5' and 3' deletion constructs of the predicted GC rich promoter region, which lacks a canonical TATA and CAAT box, revealed that a 177 nts proximal promoter element is sufficient and indispensable to drive the constitutive transcription in full strength in HepG2 hepatoma cells. In addition, we also detected the transcriptional start site using 5'-RACE (rapid amplification of cDNA ends). Our results provide an insight into transcriptional regulation of the XYLT2 gene and may contribute to understanding the manifold GAG-involving processes in health and disease.
Collapse
Affiliation(s)
- Benjamin Müller
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum NRW, Universitätsklinik der Ruhr-Universität Bochum, Bad Oeynhausen, Germany.
| | | | | | | | | |
Collapse
|
24
|
Schjoldager KTBG, Clausen H. Site-specific protein O-glycosylation modulates proprotein processing - deciphering specific functions of the large polypeptide GalNAc-transferase gene family. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1820:2079-94. [PMID: 23022508 DOI: 10.1016/j.bbagen.2012.09.014] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 09/17/2012] [Accepted: 09/19/2012] [Indexed: 01/18/2023]
Abstract
BACKGROUND Posttranslational modifications (PTMs) greatly expand the function and regulation of proteins, and glycosylation is the most abundant and diverse PTM. Of the many different types of protein glycosylation, one is quite unique; GalNAc-type (or mucin-type) O-glycosylation, where biosynthesis is initiated in the Golgi by up to twenty distinct UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts). These GalNAc-Ts are differentially expressed in cells and have different (although partly overlapping) substrate specificities, which provide for both unique functions and considerable redundancy. Recently we have begun to uncover human diseases associated with deficiencies in GalNAc-T genes (GALNTs). Thus deficiencies in individual GALNTs produce cell and protein specific effects and subtle distinct phenotypes such as hyperphosphatemia with hyperostosis (GALNT3) and dysregulated lipid metabolism (GALNT2). These phenotypes appear to be caused by deficient site-specific O-glycosylation that co-regulates proprotein convertase (PC) processing of FGF23 and ANGPTL3, respectively. SCOPE OF REVIEW Here we summarize recent progress in uncovering the interplay between human O-glycosylation and protease regulated processing and describes other important functions of site-specific O-glycosylation in health and disease. MAJOR CONCLUSIONS Site-specific O-glycosylation modifies pro-protein processing and other proteolytic events such as ADAM processing and thus emerges as an important co-regulator of limited proteolytic processing events. GENERAL SIGNIFICANCE Our appreciation of this function may have been hampered by our sparse knowledge of the O-glycoproteome and in particular sites of O-glycosylation. New strategies for identification of O-glycoproteins have emerged and recently the concept of SimpleCells, i.e. human cell lines made deficient in O-glycan extension by zinc finger nuclease gene targeting, was introduced for broad O-glycoproteome analysis.
Collapse
|
25
|
Seeger-Nukpezah T, Golemis EA. The extracellular matrix and ciliary signaling. Curr Opin Cell Biol 2012; 24:652-61. [PMID: 22819513 DOI: 10.1016/j.ceb.2012.06.002] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 05/29/2012] [Accepted: 06/11/2012] [Indexed: 12/24/2022]
Abstract
The primary cilium protrudes like an antenna from the cell surface, sensing mechanical and chemical cues provided in the cellular environment. In some tissue types, ciliary orientation to lumens allows response to fluid flow; in others, such as bone, ciliary protrusion into the extracellular matrix allows response to compression forces. The ciliary membrane contains receptors for Hedgehog, Wnt, Notch, and other potent growth factors, and in some instances also harbors integrin and cadherin family members, allowing receipt of a robust range of signals. A growing list of ciliopathies, arising from deficient formation or function of cilia, includes both developmental defects and chronic, progressive disorders such as polycystic kidney disease (PKD); changes in ciliary function have been proposed to support cancer progression. Recent findings have revealed extensive signaling dialog between cilia and extracellular matrix (ECM), with defects in cilia associated with fibrosis in multiple contexts. Further, a growing number of proteins have been determined to possess multiple roles in control of cilia and focal adhesion interactions with the ECM, further coordinating functionality. We summarize and discuss these recent findings.
Collapse
Affiliation(s)
- Tamina Seeger-Nukpezah
- Program in Developmental Therapeutics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | | |
Collapse
|
26
|
Bennett EP, Mandel U, Clausen H, Gerken TA, Fritz TA, Tabak LA. Control of mucin-type O-glycosylation: a classification of the polypeptide GalNAc-transferase gene family. Glycobiology 2012; 22:736-56. [PMID: 22183981 PMCID: PMC3409716 DOI: 10.1093/glycob/cwr182] [Citation(s) in RCA: 592] [Impact Index Per Article: 49.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 12/14/2011] [Accepted: 12/14/2011] [Indexed: 12/15/2022] Open
Abstract
Glycosylation of proteins is an essential process in all eukaryotes and a great diversity in types of protein glycosylation exists in animals, plants and microorganisms. Mucin-type O-glycosylation, consisting of glycans attached via O-linked N-acetylgalactosamine (GalNAc) to serine and threonine residues, is one of the most abundant forms of protein glycosylation in animals. Although most protein glycosylation is controlled by one or two genes encoding the enzymes responsible for the initiation of glycosylation, i.e. the step where the first glycan is attached to the relevant amino acid residue in the protein, mucin-type O-glycosylation is controlled by a large family of up to 20 homologous genes encoding UDP-GalNAc:polypeptide GalNAc-transferases (GalNAc-Ts) (EC 2.4.1.41). Therefore, mucin-type O-glycosylation has the greatest potential for differential regulation in cells and tissues. The GalNAc-T family is the largest glycosyltransferase enzyme family covering a single known glycosidic linkage and it is highly conserved throughout animal evolution, although absent in bacteria, yeast and plants. Emerging studies have shown that the large number of genes (GALNTs) in the GalNAc-T family do not provide full functional redundancy and single GalNAc-T genes have been shown to be important in both animals and human. Here, we present an overview of the GalNAc-T gene family in animals and propose a classification of the genes into subfamilies, which appear to be conserved in evolution structurally as well as functionally.
Collapse
Affiliation(s)
- Eric P Bennett
- Department of Odontology, Copenhagen Center for Glycomics, University of Copenhagen, Nørre Alle 20, DK-2200 Copenhagen N, Denmark.
| | | | | | | | | | | |
Collapse
|
27
|
Strazzabosco M, Fabris L. Development of the bile ducts: essentials for the clinical hepatologist. J Hepatol 2012; 56:1159-1170. [PMID: 22245898 PMCID: PMC3328609 DOI: 10.1016/j.jhep.2011.09.022] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 09/08/2011] [Accepted: 09/13/2011] [Indexed: 02/07/2023]
Abstract
Several cholangiopathies result from a perturbation of developmental processes. Most of these cholangiopathies are characterised by the persistence of biliary structures with foetal configuration. Developmental processes are also relevant in acquired liver diseases, as liver repair mechanisms exploit a range of autocrine and paracrine signals transiently expressed in embryonic life. We briefly review the ontogenesis of the intra- and extrahepatic biliary tree, highlighting the morphogens, growth factors, and transcription factors that regulate biliary development, and the relationships between developing bile ducts and other branching biliary structures. Then, we discuss the ontogenetic mechanisms involved in liver repair, and how these mechanisms are recapitulated in ductular reaction, a common reparative response to many forms of biliary and hepatocellular damage. Finally, we discuss the pathogenic aspects of the most important primary cholangiopathies related to altered biliary development, i.e. polycystic and fibropolycystic liver diseases, Alagille syndrome.
Collapse
Affiliation(s)
- Mario Strazzabosco
- Section of Digestive Diseases, Yale University, New Haven, CT, USA; Department of Clinical Medicine, University of Milan-Bicocca, Milan, Italy.
| | - Luca Fabris
- Department of Clinical Medicine, University of Milan-Bicocca, Milan, Italy,Department of Surgical and Gastroenterological Sciences, University of Padova, Italy
| |
Collapse
|
28
|
McCarthy KJ, Wassenhove-McCarthy DJ. The glomerular basement membrane as a model system to study the bioactivity of heparan sulfate glycosaminoglycans. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:3-21. [PMID: 22258721 PMCID: PMC3351113 DOI: 10.1017/s1431927611012682] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The glomerular basement membrane and its associated cells are critical elements in the renal ultrafiltration process. Traditionally the anionic charge associated with several carbohydrate moieties in the glomerular basement membrane are thought to form a charge selective barrier that restricts the transmembrane flux of anionic proteins across the glomerular basement membrane into the urinary space. The charge selective function, along with the size selective component of the basement membrane, serves to limit the efflux of plasma proteins from the capillary lumen. Heparan sulfate glycosaminoglycans are anionically charged carbohydrate structures attached to proteoglycan core proteins and have a role in establishing the charge selective function of the glomerular basement membrane. Although there are a large number of studies in the literature that support this concept, the results of several recent studies using molecular genetic approaches to minimize the anionic charge of the glomerular basement membrane would suggest that the role of heparan sulfate glycosaminoglycans in the glomerular capillary wall are still not yet entirely resolved, suggesting that this research area still requires new and novel exploration.
Collapse
Affiliation(s)
- Kevin J McCarthy
- Department of Pathology, LSU Health Sciences Center-Shreveport, 1501 Kings Highway, Shreveport, LA 71130-3932, USA.
| | | |
Collapse
|
29
|
Abstract
Proteoglycans (PGs) impact many aspects of kidney health and disease. Models that permit genetic dissection of PG core protein and glycosaminoglycan (GAG) function have been instrumental to understanding their roles in the kidney. Matrix-associated PGs do not serve critical structural roles in the organ, nor do they contribute significantly to the glomerular barrier under normal conditions, but their abnormal expression influences fibrosis, inflammation, and progression of kidney disease. Most core proteins are dispensable for nephrogenesis (glypican-3 being an exception) and for maintenance of function in adult life, but their loss alters susceptibility to experimental kidney injury. In contrast, kidney development is exquisitely sensitive to GAG expression and fine structure as evidenced by the severe phenotypes of mutants for genes involved in GAG biosynthesis. This article reviews PG expression in normal kidney and the abnormalities caused by their disruption in mice and man.
Collapse
Affiliation(s)
- Scott J Harvey
- INSERM Avenir U983, Hôpital Necker-Enfants Malades, Paris, France
| |
Collapse
|
30
|
Weinstein T, Evron Z, Trebicz-Geffen M, Aviv M, Robinson D, Kollander Y, Nevo Z. β-D-xylosides stimulate GAG synthesis in chondrocyte cultures due to elevation of the extracellular GAG domains, accompanied by the depletion of the intra-pericellular GAG pools, with alterations in the GAG profiles. Connect Tissue Res 2011; 53:169-79. [PMID: 22149722 DOI: 10.3109/03008207.2011.620190] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The familial disease of hereditary multiple exostoses is characterized by abnormal skeletal deformities requiring extensive surgical procedures. In hereditary multiple exostoses patients there is a shortage in the pericellular glycosaminoglycan (GAG) of heparan sulfate (HS), related to defective activity of HS glycosyltransferases, mainly in the pericellular regions of chondrocytes. This study searched for a novel approach employing xylosides with different aglycone groups priming a variety of GAG chains, in attempting to alter the GAG compositional profile. Cell cultures of patients with osteochondroma responded to p-nitrophenyl β-D-xyloside by a significant increase in total GAG synthesis, expressed mainly in the extracellular domains, limited to chondroitin sulfate). The different β-D-xylosides, in addition to increasing the synthesis of extracellular GAGs, led to a significant depletion of the intracellular GAG domains. In mouse chondrocyte cultures, β-D-xylosides with different aglycones created a unique distribution of the GAG pools. Of special interest was the finding that the naphthalene methanol β-D-xyloside showed the highest absolute levels of HS-GAGs in both extracellular and intra-pericellular moieties compared with other β-D-xylosides and with controls without xyloside. In summary, β-D-xylosides can be utilized in chondrocyte cultures to modify the distribution of GAGs between the extracellular and intracellular compartments. In addition, xylosides may alter the profile of specific GAG chains in each moiety.
Collapse
Affiliation(s)
- Talia Weinstein
- Department of Nephrology, Tel Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | | | | | | | | | | | | |
Collapse
|
31
|
Miyake K, Hirasawa T, Soutome M, Itoh M, Goto YI, Endoh K, Takahashi K, Kudo S, Nakagawa T, Yokoi S, Taira T, Inazawa J, Kubota T. The protocadherins, PCDHB1 and PCDH7, are regulated by MeCP2 in neuronal cells and brain tissues: implication for pathogenesis of Rett syndrome. BMC Neurosci 2011; 12:81. [PMID: 21824415 PMCID: PMC3160964 DOI: 10.1186/1471-2202-12-81] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 08/08/2011] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Rett syndrome is a neurodevelopmental and autistic disease caused by mutations of Methyl-CpG-binding protein 2 (MECP2) gene. MeCP2 protein is mainly expressed in neurons and binds to methylated gene promoters to suppress their expression, indicating that Rett syndrome is caused by the deregulation of target genes in neurons. However, it is likely that there are more unidentified neuronal MeCP2-targets associated with the neurological features of RTT. RESULTS Using a genome-microarray approach, we found 22 genomic regions that contain sites potentially regulated by MeCP2 based on the features of MeCP2 binding, DNA methylation, and repressive histone modification in human cell lines. Within these regions, Chromatin immunoprecipitation (ChIP) analysis revealed that MeCP2 binds to the upstream regions of the protocadherin genes PCDHB1 and PCDH7 in human neuroblastoma SH-SY5Y cells. PCDHB1 and PCDH7 promoter activities were down-regulated by MeCP2, but not by MBD-deleted MeCP2. These gene expression were up-regulated following MeCP2 reduction with siRNA in SH-SY5Y cells and in the brains of Mecp2-null mice. Furthermore, PCDHB1 was up-regulated in postmortem brains from Rett syndrome patients. CONCLUSIONS We identified MeCP2 target genes that encode neuronal adhesion molecules using ChIP-on-BAC array approach. Since these protocadherin genes are generally essential for brain development, aberrant regulation of these molecules may contribute to the pathogenesis of the neurological features observed in Rett syndrome.
Collapse
Affiliation(s)
- Kunio Miyake
- Department of Epigenetic Medicine, University of Yamanashi, Chuo, Yamanashi, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Eames BF, Yan YL, Swartz ME, Levic DS, Knapik EW, Postlethwait JH, Kimmel CB. Mutations in fam20b and xylt1 reveal that cartilage matrix controls timing of endochondral ossification by inhibiting chondrocyte maturation. PLoS Genet 2011; 7:e1002246. [PMID: 21901110 PMCID: PMC3161922 DOI: 10.1371/journal.pgen.1002246] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Accepted: 07/01/2011] [Indexed: 11/18/2022] Open
Abstract
Differentiating cells interact with their extracellular environment over time. Chondrocytes embed themselves in a proteoglycan (PG)-rich matrix, then undergo a developmental transition, termed "maturation," when they express ihh to induce bone in the overlying tissue, the perichondrium. Here, we ask whether PGs regulate interactions between chondrocytes and perichondrium, using zebrafish mutants to reveal that cartilage PGs inhibit chondrocyte maturation, which ultimately dictates the timing of perichondral bone development. In a mutagenesis screen, we isolated a class of mutants with decreased cartilage matrix and increased perichondral bone. Positional cloning identified lesions in two genes, fam20b and xylosyltransferase1 (xylt1), both of which encode PG synthesis enzymes. Mutants failed to produce wild-type levels of chondroitin sulfate PGs, which are normally abundant in cartilage matrix, and initiated perichondral bone formation earlier than their wild-type siblings. Primary chondrocyte defects might induce the bone phenotype secondarily, because mutant chondrocytes precociously initiated maturation, showing increased and early expression of such markers as runx2b, collagen type 10a1, and ihh co-orthologs, and ihha mutation suppressed early perichondral bone in PG mutants. Ultrastructural analyses demonstrated aberrant matrix organization and also early cellular features of chondrocyte hypertrophy in mutants. Refining previous in vitro reports, which demonstrated that fam20b and xylt1 were involved in PG synthesis, our in vivo analyses reveal that these genes function in cartilage matrix production and ultimately regulate the timing of skeletal development.
Collapse
Affiliation(s)
- B Frank Eames
- Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America.
| | | | | | | | | | | | | |
Collapse
|
33
|
Sarrazin S, Lamanna WC, Esko JD. Heparan sulfate proteoglycans. Cold Spring Harb Perspect Biol 2011; 3:cshperspect.a004952. [PMID: 21690215 DOI: 10.1101/cshperspect.a004952] [Citation(s) in RCA: 1018] [Impact Index Per Article: 78.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Heparan sulfate proteoglycans are found at the cell surface and in the extracellular matrix, where they interact with a plethora of ligands. Over the last decade, new insights have emerged regarding the mechanism and biological significance of these interactions. Here, we discuss changing views on the specificity of protein-heparan sulfate binding and the activity of HSPGs as receptors and coreceptors. Although few in number, heparan sulfate proteoglycans have profound effects at the cellular, tissue, and organismal level.
Collapse
Affiliation(s)
- Stephane Sarrazin
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California 92093, USA
| | | | | |
Collapse
|
34
|
Abstract
Heparan sulfate proteoglycans are found at the cell surface and in the extracellular matrix, where they interact with a plethora of ligands. Over the last decade, new insights have emerged regarding the mechanism and biological significance of these interactions. Here, we discuss changing views on the specificity of protein-heparan sulfate binding and the activity of HSPGs as receptors and coreceptors. Although few in number, heparan sulfate proteoglycans have profound effects at the cellular, tissue, and organismal level.
Collapse
Affiliation(s)
- Stephane Sarrazin
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California 92093, USA
| | | | | |
Collapse
|
35
|
Gmeiner WH, Reinhold WC, Pommier Y. Genome-wide mRNA and microRNA profiling of the NCI 60 cell-line screen and comparison of FdUMP[10] with fluorouracil, floxuridine, and topoisomerase 1 poisons. Mol Cancer Ther 2011; 9:3105-14. [PMID: 21159603 DOI: 10.1158/1535-7163.mct-10-0674] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A profile of microRNA (miRNA) and mRNA expression patterns across the NCI-60 cell-line screen was analyzed to identify expression signatures that correlate with sensitivity to FdUMP[10], fluorouracil (5FU), floxuridine (FdU), topotecan, and irinotecan. Genome-wide profile analyses revealed FdUMP[10] resembles FdU most closely and shows dissimilarities with 5FU. FdUMP[10] had the largest dynamic range of any of these drugs across the NCI-60 indicative of cancer cell-specific activity. Genes involved in endocytosis, such as clathrin (CLTC), SNF8, annexin A6 (ANXA6), and amyloid protein-binding 2 (APPBP2) uniquely correlated with sensitivity to FdUMP[10], consistent with a protein-mediated cellular uptake of FdUMP[10]. Genes involved in nucleotide metabolism were enriched for the three fluoropyrimidine drugs, with the expression profile for 5FU correlated to an RNA-mediated cytotoxic mechanism, whereas expression of glycosyltransferases (XYLT2) that use UDP sugars as substrates and the nucleoside diphosphatase and metastasis suppressor NM23 (NME1) were associated with FdUMP[10] sensitivity. Topotecan and irinotecan had significant negative correlations with miR-24, a miRNA with a high aggregate P(CT) score for topoisomerase 1 (Top1). Our results reveal significant new correlations between FdUMP[10] and Top1 poisons, as well as new information on the unique cytotoxic mechanism and genomic signature of FdUMP[10].
Collapse
Affiliation(s)
- William H Gmeiner
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
| | | | | |
Collapse
|
36
|
|
37
|
Roch C, Kuhn J, Kleesiek K, Götting C. Differences in gene expression of human xylosyltransferases and determination of acceptor specificities for various proteoglycans. Biochem Biophys Res Commun 2010; 391:685-91. [PMID: 19944077 DOI: 10.1016/j.bbrc.2009.11.121] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Accepted: 11/19/2009] [Indexed: 10/20/2022]
Abstract
The xylosyltransferase (XT) isoforms XT-I and XT-II initiate the posttranslational glycosaminoglycan (GAG) synthesis. Here, we determined the relative expression of both isoforms in 33 human cell lines. The majority of tested cell lines showed dominant XYLT2 gene expression, while only in 23132/87, JAR, NCI-H510A and THP-1 was the XT-I mRNA expression higher. Nearly equal expression levels were detected in six cell lines. Additionally, to shed light on putative differences in acceptor specificities the acceptor properties of potential acceptor sequences were determined. Peptides were expressed as glutathione-S-transferase fusion proteins containing putative or known GAG attachment sites of in vivo proteoglycans. Kinetic analysis showed that K(m) and V(max) values for XT-I mediated xylosylation were slightly higher than those for XT-II, and that XT-I showed a lesser stringency concerning the acceptor sequence. Mutagenesis of the bikunin peptide sequence in the G-S-G attachment site and flanking regions generated potential acceptor molecules. Here, mutations on the N-terminal side and the attachment site were found to be more susceptible to a loss of acceptor function than mutations in the C-terminus. Altogether the known consensus sequence a-a-a-a-G-S-G-a-a/G-a ('a' representing Asp or Glu) for XT-I mediated xylosylation could be approved and additionally extended to apply to XT-II as well.
Collapse
Affiliation(s)
- Christina Roch
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum NRW, Universitätsklinik der Ruhr-Universität Bochum, 32545 Bad Oeynhausen, Germany
| | | | | | | |
Collapse
|
38
|
Kuhn J, Gressner OA, Götting C, Gressner AM, Kleesiek K. Increased serum xylosyltransferase activity in patients with liver fibrosis. Clin Chim Acta 2009; 409:123-6. [PMID: 19755118 DOI: 10.1016/j.cca.2009.09.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Revised: 09/04/2009] [Accepted: 09/04/2009] [Indexed: 01/06/2023]
Abstract
BACKGROUND We investigated the xylosyltransferase (XT) activity in the serum of liver fibrotic patients with hepatitis C virus induced liver fibrosis at different stages as determined according to the scoring system of Desmet and Scheuer. METHODS Measurement of XT activity was performed by liquid chromatography-tandem mass spectrometry. RESULTS We found that serum XT activity in males (n=59, median+/-SD, 27.2+/-2.8 mU/L, p<0.001) and females (n=54, 23.6+/-3.0 mU/L, p<0.01) with liver fibrosis is significantly elevated in comparison to a corresponding healthy control cohort of males (n=50, 23.9+/-2.8 mU/L) and females (n=52, 21.5+/-3.7 mU/L), respectively. Of note, independent from gender, serum XT activity positively correlated with the stage of fibrosis but declined again in patients with histologically proven cirrhosis. CONCLUSIONS XT activity is increased in the serum of patients with liver fibrosis at different stages, pointing to a possible pathogenetic role in elevated proteoglycan biosynthesis in fibrotic remodeling of this organ during chronic injury.
Collapse
Affiliation(s)
- Joachim Kuhn
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Georgstrasse 11, 32545 Bad Oeynhausen, Germany.
| | | | | | | | | |
Collapse
|
39
|
Condac E, Dale GL, Bender-Neal D, Ferencz B, Towner R, Hinsdale ME. Xylosyltransferase II is a significant contributor of circulating xylosyltransferase levels and platelets constitute an important source of xylosyltransferase in serum. Glycobiology 2009; 19:829-33. [PMID: 19389916 PMCID: PMC2704898 DOI: 10.1093/glycob/cwp058] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 03/24/2009] [Accepted: 04/15/2009] [Indexed: 11/13/2022] Open
Abstract
Circulating glycosyltransferases including xylosyltransferases I (XylT1) and II (XylT2) are potential serum biomarkers for various diseases. Understanding what influences the serum activity of these enzymes as well as the sources of these enzymes is important to interpreting the significance of alterations in enzyme activity during disease. This article demonstrates that in the mouse and human the predominant XylT in serum is XylT2. Furthermore, that total XylT levels in human serum are approximately 200% higher than those in plasma due in part to XylT released by platelets during blood clotting in vitro. In addition, the data from Xylt2 knock-out mice and mice with liver neoplasia show that liver is a significant source of serum XylT2 activity. The data presented suggest that serum XylT levels may be an informative biomarker in patients who suffer from diseases affecting platelet and/or liver homeostasis.
Collapse
Affiliation(s)
- Eduard Condac
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078
| | - George L Dale
- Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Diane Bender-Neal
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599
| | - Beatrix Ferencz
- Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078
| | - Rheal Towner
- Advanced Magnetic Resonance Center, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Myron E Hinsdale
- To whom correspondence should be addressed: Tel: +1-405-744-8103; Fax: +1-405-744-6263; e-mail
| |
Collapse
|
40
|
Lindahl U, Li JP. Interactions between heparan sulfate and proteins-design and functional implications. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 276:105-59. [PMID: 19584012 DOI: 10.1016/s1937-6448(09)76003-4] [Citation(s) in RCA: 206] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Heparan sulfate (HS) proteoglycans at cell surfaces and in the extracellular matrix of most animal tissues are essential in development and homeostasis, and variously implicated in disease processes. Functions of HS polysaccharide chains depend on ionic interactions with a variety of proteins including growth factors and their receptors. Negatively charged sulfate and carboxylate groups are arranged in various types of domains, generated through strictly regulated biosynthetic reactions and with enormous potential for structural variability. The level of specificity of HS-protein interactions is assessed through binding experiments in vitro using saccharides of defined composition, signaling assays in cell culture, and targeted disruption of genes for biosynthetic enzymes followed by phenotype analysis. While some protein ligands appear to require strictly defined HS structure, others bind to variable saccharide domains without any apparent dependence on distinct saccharide sequence. These findings raise intriguing questions concerning the functional significance of regulation in HS biosynthesis.
Collapse
Affiliation(s)
- Ulf Lindahl
- Department of Medical Biochemistry and Microbiology, University of Uppsala, Uppsala, Sweden
| | | |
Collapse
|
41
|
Abstract
PURPOSE OF REVIEW Clearance of triglyceride-rich lipoprotein remnants by the liver is a key step in preventing hypertriglyceridemia, an independent risk factor for cardiovascular disease. We review recent genetic evidence that heparan sulfate proteoglycans work in concert with the LDL receptor in the liver to facilitate binding and clearance of both triglyceride and cholesterol-rich lipoproteins from the circulation. RECENT FINDINGS Partial reduction of sulfation of liver heparan sulfate using the Cre-loxP system caused accumulation of hepatic and dietary triglyceride-rich lipoprotein particles due to delayed clearance. Compounding the mutation with LDL receptor deficiency caused enhanced accumulation of both cholesterol and triglyceride-rich particles compared with mice lacking only LDL receptors. These findings provide the first genetic evidence that hepatic heparan sulfate proteoglycans play a central role in the clearance of lipoproteins by the liver and work independently of LDL receptors. SUMMARY A role for hepatocyte heparan sulfate in lipoprotein metabolism has now been genetically established in mice. Given this finding, mild, but clinically relevant, hyperlipidemias in human patients may be a result of alterations in heparan sulfate structure or possible genetic polymorphisms in the relevant biosynthetic genes.
Collapse
Affiliation(s)
- Joseph R Bishop
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093-0687, USA
| | | | | |
Collapse
|
42
|
Mans DA, Voest EE, Giles RH. All along the watchtower: is the cilium a tumor suppressor organelle? Biochim Biophys Acta Rev Cancer 2008; 1786:114-25. [PMID: 18343234 DOI: 10.1016/j.bbcan.2008.02.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 02/10/2008] [Accepted: 02/14/2008] [Indexed: 01/09/2023]
Abstract
Cilia or flagella have been around since almost the beginning of life, and have now developed specialized cell-type specific functions from locomotion to acting as environmental sensors participating in cell signalling. Genetic defects affecting cilia result in a myriad of pathological instances, including infertility, obesity, blindness, deafness, skeletal malformations, and lung problems. However, the consistency in which the common kidney cyst is coupled with cilia dysfunction has raised interest in the possibility that ciliary dysfunction might contribute to other neoplasms as well. A suite of recent papers convincingly linking cilia to hedgehog signalling, platelet-derived growth factor signalling, Wnt signalling and the von Hippel-Lindau tumor suppressor protein has rapidly expanded the knowledge base connecting cilia to cancer. We propose that these data support the notion of the cilium as a cellular Watchtower, whose absence can be an initiating event in neoplastic growth. Furthermore, we predict that we are just now seeing the tip of the iceberg, and that the list of cancers associated with altered ciliary signalling will grow exponentially in the next few years.
Collapse
Affiliation(s)
- Dorus A Mans
- Department of Medical Oncology, University Medical Center Utrecht, The Netherlands
| | | | | |
Collapse
|
43
|
Journal Club. Kidney Int 2007. [DOI: 10.1038/sj.ki.5002463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|