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Roessner R, Michelarakis N, Gräter F, Aponte-Santamaría C. Mechanical forces control the valency of the malaria adhesin VAR2CSA by exposing cryptic glycan binding sites. PLoS Comput Biol 2023; 19:e1011726. [PMID: 38117828 PMCID: PMC10786402 DOI: 10.1371/journal.pcbi.1011726] [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] [Received: 08/02/2023] [Revised: 01/12/2024] [Accepted: 12/02/2023] [Indexed: 12/22/2023] Open
Abstract
Plasmodium falciparum (Pf) is responsible for the most lethal form of malaria. VAR2CSA is an adhesin protein expressed by this parasite at the membrane of infected erythrocytes for attachment to the placenta, leading to pregnancy-associated malaria. VAR2CSA is a large 355 kDa multidomain protein composed of nine extracellular domains, a transmembrane helix, and an intracellular domain. VAR2CSA binds to Chondroitin Sulphate A (CSA) of the proteoglycan matrix of the placenta. Shear flow, as the one occurring in blood, has been shown to enhance the (VAR2CSA-mediated) adhesion of Pf-infected erythrocytes on the CSA-matrix. However, the underlying molecular mechanism governing this enhancement has remained elusive. Here, we address this question by using equilibrium, force-probe, and docking-based molecular dynamics simulations. We subjected the VAR2CSA protein-CSA sugar complex to a force mimicking the tensile force exerted on this system due to the shear of the flowing blood. We show that upon this force exertion, VAR2CSA undergoes a large opening conformational transition before the CSA sugar chain dissociates from its main binding site. This preferential order of events is caused by the orientation of the molecule during elongation, as well as the strong electrostatic attraction of the sugar to the main protein binding site. Upon opening, two additional cryptic CSA binding sites get exposed and a functional dodecameric CSA molecule can be stably accommodated at these force-exposed positions. Thus, our results suggest that mechanical forces increase the avidity of VAR2CSA by turning it from a monovalent to a multivalent state. We propose this to be the molecular cause of the observed shear-enhanced adherence. Mechanical control of the valency of VAR2CSA is an intriguing hypothesis that can be tested experimentally and which is of relevance for the understanding of the malaria infection and for the development of anti placental-malaria vaccines targeting VAR2CSA.
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Affiliation(s)
- Rita Roessner
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Nicholas Michelarakis
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Frauke Gräter
- Molecular Biomechanics Group, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
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2
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Noborn F, Nilsson J, Larson G. Site-specific glycosylation of proteoglycans: a revisited frontier in proteoglycan research. Matrix Biol 2022; 111:289-306. [PMID: 35840015 DOI: 10.1016/j.matbio.2022.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 06/11/2022] [Accepted: 07/11/2022] [Indexed: 11/29/2022]
Abstract
Proteoglycans (PGs), a class of carbohydrate-modified proteins, are present in essentially all metazoan organisms investigated to date. PGs are composed of glycosaminoglycan (GAG) chains attached to various core proteins and are important for embryogenesis and normal homeostasis. PGs exert many of their functions via their GAG chains and understanding the details of GAG-ligand interactions has been an essential part of PG research. Although PGs are also involved in many diseases, the number of GAG-related drugs used in the clinic is yet very limited, indicating a lack of detailed structure-function understanding. Structural analysis of PGs has traditionally been obtained by first separating the GAG chains from the core proteins, after which the two components are analyzed separately. While this strategy greatly facilitates the analysis, it precludes site-specific information and introduces either a "GAG" or a "core protein" perspective on the data interpretation. Mass-spectrometric (MS) glycoproteomic approaches have recently been introduced, providing site-specific information on PGs. Such methods have revealed a previously unknown structural complexity of the GAG linkage regions and resulted in identification of several novel CSPGs and HSPGs in humans and in model organisms, thereby expanding our view on PG complexity. In light of these findings, we discuss here if the use of such MS-based techniques, in combination with various functional assays, can also be used to expand our functional understanding of PGs. We have also summarized the site-specific information of all human PGs known to date, providing a theoretical framework for future studies on site-specific functional analysis of PGs in human pathophysiology.
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Affiliation(s)
- Fredrik Noborn
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; Department of Laboratory Medicine, Sundsvall County Hospital, Sweden.
| | - Jonas Nilsson
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; Proteomics Core Facility, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Göran Larson
- Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
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3
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Spliid CB, Toledo AG, Sanderson P, Mao Y, Gatto F, Gustavsson T, Choudhary S, Saldanha AL, Vogelsang RP, Gögenur I, Theander TG, Leach FE, Amster IJ, Esko JD, Salanti A, Clausen TM. The specificity of the malarial VAR2CSA protein for chondroitin sulfate depends on 4-O-sulfation and ligand accessibility. J Biol Chem 2021; 297:101391. [PMID: 34762909 DOI: 10.1016/j.jbc.2021.101391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 10/19/2022] Open
Abstract
Placental malaria infection is mediated by the binding of the malarial VAR2CSA protein to the placental glycosaminoglycan, chondroitin sulfate. Recombinant sub-fragments of VAR2CSA (rVAR2) have also been shown to bind specifically and with high affinity to cancer cells and tissues, suggesting the presence of a shared type of oncofetal chondroitin sulfate (ofCS) in the placenta and in tumors. However, the exact structure of ofCS and what determines the selective tropism of VAR2CSA remains poorly understood. In this study, ofCS was purified by affinity chromatography using rVAR2 and subjected to detailed structural analysis. We found high levels of N-acetylgalactosamine 4-O-sulfation (∼80-85%) in placenta- and tumor-derived ofCS. This level of 4-O-sulfation was also found in other tissues that do not support parasite sequestration, suggesting that VAR2CSA tropism is not exclusively determined by placenta- and tumor-specific sulfation. Here, we show that both placenta and tumors contain significantly more chondroitin sulfate moieties of higher molecular weight than other tissues. In line with this, CHPF and CHPF2, which encode proteins required for chondroitin polymerization, are significantly upregulated in most cancer types. CRISPR/Cas9 targeting of CHPF and CHPF2 in tumor cells reduced the average molecular weight of cell-surface chondroitin sulfate and resulted in a marked reduction of rVAR2 binding. Finally, utilizing a cell-based glycocalyx model, we showed that rVAR2 binding correlates with the length of the chondroitin sulfate chains in the cellular glycocalyx. These data demonstrate that the total amount and cellular accessibility of chondroitin sulfate chains impact rVAR2 binding and thus malaria infection.
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Affiliation(s)
- Charlotte B Spliid
- Department of Cellular and Molecular Medicine, and Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA, USA; Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Disease, Copenhagen University Hospital, 2200 Copenhagen, Denmark
| | - Alejandro Gomez Toledo
- Department of Cellular and Molecular Medicine, and Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA, USA; Department of Clinical Sciences, Division of Infection Medicine, Lund University, Sweden
| | | | - Yang Mao
- School of Pharmaceutical Sciences, Sun Yat-sen University, 510006 Guangzhou, China and Guangdong Provincial Key Laboratory of Drug Non-Clinical Evaluation and Research, 510990 Guangzhou, China
| | - Francesco Gatto
- Department of Biology and Biological Engineering, Chalmers University of Technology, 42196 Gothenburg, Sweden
| | - Tobias Gustavsson
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Disease, Copenhagen University Hospital, 2200 Copenhagen, Denmark
| | - Swati Choudhary
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Disease, Copenhagen University Hospital, 2200 Copenhagen, Denmark
| | - Ana L Saldanha
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Disease, Copenhagen University Hospital, 2200 Copenhagen, Denmark
| | - Rasmus P Vogelsang
- Center for Surgical Science, Department of Surgery, Zealand University Hospital, DK-4600 Koege, Denmark
| | - Ismail Gögenur
- Center for Surgical Science, Department of Surgery, Zealand University Hospital, DK-4600 Koege, Denmark
| | - Thor G Theander
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Disease, Copenhagen University Hospital, 2200 Copenhagen, Denmark
| | - Franklin E Leach
- Department of Environmental Health Science, University of Georgia, Athens, GA 30602
| | | | - Jeffrey D Esko
- Department of Cellular and Molecular Medicine, and Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA, USA
| | - Ali Salanti
- Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Disease, Copenhagen University Hospital, 2200 Copenhagen, Denmark
| | - Thomas Mandel Clausen
- Department of Cellular and Molecular Medicine, and Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA, USA; Centre for Medical Parasitology at Department for Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen and Department of Infectious Disease, Copenhagen University Hospital, 2200 Copenhagen, Denmark.
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4
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Gyapon-Quast F, Goicoechea de Jorge E, Malik T, Wu N, Yu J, Chai W, Feizi T, Liu Y, Pickering MC. Defining the Glycosaminoglycan Interactions of Complement Factor H-Related Protein 5. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2021; 207:534-541. [PMID: 34193601 PMCID: PMC8313009 DOI: 10.4049/jimmunol.2000072] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 05/06/2021] [Indexed: 01/09/2023]
Abstract
Complement activation is an important mediator of kidney injury in glomerulonephritis. Complement factor H (FH) and FH-related protein 5 (FHR-5) influence complement activation in C3 glomerulopathy and IgA nephropathy by differentially regulating glomerular complement. FH is a negative regulator of complement C3 activation. Conversely, FHR-5 in vitro promotes C3 activation either directly or by competing with FH for binding to complement C3b. The FH-C3b interaction is enhanced by surface glycosaminoglycans (GAGs) and the FH-GAG interaction is well-characterized. In contrast, the contributions of carbohydrates to the interaction of FHR-5 and C3b are unknown. Using plate-based and microarray technologies we demonstrate that FHR-5 interacts with sulfated GAGs and that this interaction is influenced by the pattern and degree of GAG sulfation. The FHR-5-GAG interaction that we identified has functional relevance as we could show that the ability of FHR-5 to prevent binding of FH to surface C3b is enhanced by surface kidney heparan sulfate. Our findings are important in understanding the molecular basis of the binding of FHR-5 to glomerular complement and the role of FHR-5 in complement-mediated glomerular disease.
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Affiliation(s)
- Frederick Gyapon-Quast
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom;,Centre for Inflammatory Disease, Department of Immunology and Inflammation, Imperial College London, London, United Kingdom; and
| | - Elena Goicoechea de Jorge
- Department of Immunology, Complutense University and Research Institute Hospital 12 de Octubre, Madrid, Spain
| | - Talat Malik
- Centre for Inflammatory Disease, Department of Immunology and Inflammation, Imperial College London, London, United Kingdom; and
| | - Nian Wu
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Jin Yu
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Wengang Chai
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Ten Feizi
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Yan Liu
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Matthew C. Pickering
- Centre for Inflammatory Disease, Department of Immunology and Inflammation, Imperial College London, London, United Kingdom; and
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5
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Tomlinson A, Semblat JP, Gamain B, Chêne A. VAR2CSA-Mediated Host Defense Evasion of Plasmodium falciparum Infected Erythrocytes in Placental Malaria. Front Immunol 2021; 11:624126. [PMID: 33633743 PMCID: PMC7900151 DOI: 10.3389/fimmu.2020.624126] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/23/2020] [Indexed: 12/04/2022] Open
Abstract
Over 30 million women living in P. falciparum endemic areas are at risk of developing malaria during pregnancy every year. Placental malaria is characterized by massive accumulation of infected erythrocytes in the intervillous space of the placenta, accompanied by infiltration of immune cells, particularly monocytes. The consequent local inflammation and the obstruction of the maternofetal exchanges can lead to severe clinical outcomes for both mother and child. Even if protection against the disease can gradually be acquired following successive pregnancies, the malaria parasite has developed a large panel of evasion mechanisms to escape from host defense mechanisms and manipulate the immune system to its advantage. Infected erythrocytes isolated from placentas of women suffering from placental malaria present a unique phenotype and express the pregnancy-specific variant VAR2CSA of the Plasmodium falciparum Erythrocyte Membrane Protein (PfEMP1) family at their surface. The polymorphic VAR2CSA protein is able to mediate the interaction of infected erythrocytes with a variety of host cells including placental syncytiotrophoblasts and leukocytes but also with components of the immune system such as non-specific IgM. This review summarizes the described VAR2CSA-mediated host defense evasion mechanisms employed by the parasite during placental malaria to ensure its survival and persistence.
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Affiliation(s)
- Alice Tomlinson
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Jean-Philippe Semblat
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Benoît Gamain
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Arnaud Chêne
- Université de Paris, Biologie Intégrée du Globule Rouge, UMR_S1134, BIGR, INSERM, Paris, France.,Institut National de la Transfusion Sanguine, Paris, France.,Laboratory of Excellence GR-Ex, Paris, France
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6
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Lan Y, Liu Y, He Y, Liu F, Xv H, Feng K, Zhang Z, Shi Z, Zhang X, Zhang L. A single injection of bleomycin reduces glycosaminoglycan sulfation up to 30 days in the C57BL/6 mouse model of lung fibrosis. Int J Biol Macromol 2020; 160:319-327. [PMID: 32422263 DOI: 10.1016/j.ijbiomac.2020.05.087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 04/06/2020] [Accepted: 05/10/2020] [Indexed: 12/13/2022]
Abstract
Bleomycin is a clinically used anticancer drug, but it induces lung fibrosis in certain cancer patients with unknown mechanism. Glycosaminoglycans (GAGs) are required for lung morphogenesis during animal development. In current study, GAG disaccharides including heparan sulfate (HS) and chondroitin sulfate (CS) from bleomycin-induced and control lung tissues in lung fibrosis mouse model were tagged with 1-phenyl-3-methyl-5-pyrazolone (PMP) and deuterated PMP, respectively. The differentially isotope-tagged disaccharides were quantitatively compared by LC-MS. At day 10, the amount of CS disaccharides (U0a0, U0a6, and U0a4) and non-sulfated HS disaccharide (U0A0) were increased by 1.3-, 1.6-, 11.7-, and 2.2-fold, respectively, whereas the amount of CS disaccharide (U0a2), hyaluranan disaccharide (UβA0), and six HS disaccharides (U0A6, U2A0, U0H6, U0S0, U2S0, and U2S6) were decreased from1.1- to 14.3-fold compared to that of the controls. At day 15, under-sulfation of both HS and CS disaccharides was persisted. At day 30, the CS disaccharide compositions were recovered to that of the control levels whereas the HS were still remarkably under-sulfated. In conclusion, GAGs, especially HS, from fibrotic lungs induced by a single injection of bleomycin were significantly under-sulfated up to 30 days, suggesting GAGs might be another class of defective signaling molecules involved in bleomycin-induced lung fibrosis.
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Affiliation(s)
- Ying Lan
- Systems Biology and Medicine Center for Complex Diseases, the Affiliated Hospital of Qingdao University, Qingdao 266003, China; College of Food Science and engineering, Northwest A&F University, 712100, China
| | - Yong Liu
- Systems Biology and Medicine Center for Complex Diseases, the Affiliated Hospital of Qingdao University, Qingdao 266003, China; School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Yanli He
- Systems Biology and Medicine Center for Complex Diseases, the Affiliated Hospital of Qingdao University, Qingdao 266003, China
| | - Feng Liu
- School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China; Weifang Medical College, Weifang 261031, China
| | - Huixin Xv
- School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Kun Feng
- School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Zhenkun Zhang
- School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Zhaoyu Shi
- School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Xiaolei Zhang
- School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Lijuan Zhang
- Systems Biology and Medicine Center for Complex Diseases, the Affiliated Hospital of Qingdao University, Qingdao 266003, China.
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7
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Clark RL. Genesis of placental sequestration in malaria and possible targets for drugs for placental malaria. Birth Defects Res 2019; 111:569-583. [PMID: 30919596 PMCID: PMC7432169 DOI: 10.1002/bdr2.1496] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 01/11/2023]
Abstract
Malaria during pregnancy results in intrauterine growth restriction, fetal anemia, and infant mortality. Women are more susceptible to malaria during pregnancy due to malaria‐induced inflammation and the sequestration of infected red blood cells in the placenta, which bind to the chondroitin sulfate portion of syndecan‐1 on the syncytiotrophoblast and in the intervillous space. Syndecan‐1 is a dimeric proteoglycan with an extracellular ectodomain that is cleaved from the transmembrane domain (referred to as “shedding”) by matrix metalloproteinases (MMPs), likely the secreted MMP‐9. The ectodomain includes four binding sites for chondroitin sulfate, which are proximal to the transmembrane domain, and six distal binding sites primarily for heparan sulfate. This “shedding” of syndecan‐1 is inhibited by the presence of the heparan sulfate chains, which can be removed by heparanase. The intervillous space contains fibrin strands and syndecan‐1 ectodomains free of heparan sulfate. The following is proposed as the sequence of events that leads to and is primarily responsible for sequestration in the intervillous space of the placenta. Inflammation associated with malaria triggers increased heparanase activity that degrades the heparan sulfate on the membrane‐bound syndecan‐1. Inflammation also upregulates MMP‐9 and the removal of heparan sulfate gives MMP‐9 access to cleave syndecan‐1, thereby releasing dimeric syndecan‐1 ectodomains with at least four chondroitin sulfate chains attached. These multivalent ectodomains bind infected RBCs together leading to their aggregation and entrapment in intervillous fibrin. This mechanism suggests possible new targets for anti‐placental malaria drugs such as the inhibition of MMP‐9. Doxycycline is an antimalarial drug which inhibits MMP‐9.
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8
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Xu L, Tang L, Zhang L. Proteoglycans as miscommunication biomarkers for cancer diagnosis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 162:59-92. [DOI: 10.1016/bs.pmbts.2018.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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9
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Identification of Heparin Modifications and Polysaccharide Inhibitors of Plasmodium falciparum Merozoite Invasion That Have Potential for Novel Drug Development. Antimicrob Agents Chemother 2017; 61:AAC.00709-17. [PMID: 28893781 DOI: 10.1128/aac.00709-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 09/03/2017] [Indexed: 11/20/2022] Open
Abstract
Despite recent successful control efforts, malaria remains a leading global health burden. Alarmingly, resistance to current antimalarials is increasing and the development of new drug families is needed to maintain malaria control. Current antimalarials target the intraerythrocytic developmental stage of the Plasmodium falciparum life cycle. However, the invasive extracellular parasite form, the merozoite, is also an attractive target for drug development. We have previously demonstrated that heparin-like molecules, including those with low molecular weights and low anticoagulant activities, are potent and specific inhibitors of merozoite invasion and blood-stage replication. Here we tested a large panel of heparin-like molecules and sulfated polysaccharides together with various modified chemical forms for their inhibitory activity against P. falciparum merozoite invasion. We identified chemical modifications that improve inhibitory activity and identified several additional sulfated polysaccharides with strong inhibitory activity. These studies have important implications for the further development of heparin-like molecules as antimalarial drugs and for understanding merozoite invasion.
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10
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Molecular dissection of placental malaria protein VAR2CSA interaction with a chemo-enzymatically synthesized chondroitin sulfate library. Glycoconj J 2016; 33:985-994. [DOI: 10.1007/s10719-016-9685-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 05/20/2016] [Accepted: 05/24/2016] [Indexed: 12/27/2022]
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11
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Shioiri T, Tsuchimoto J, Watanabe H, Sugiura N. Sequence determination of synthesized chondroitin sulfate dodecasaccharides. Glycobiology 2016; 26:592-606. [PMID: 26791444 DOI: 10.1093/glycob/cww008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/15/2016] [Indexed: 11/14/2022] Open
Abstract
Chondroitin sulfate (CS) is a linear acidic polysaccharide composed of repeating disaccharide units of glucuronic acid and N-acetyl-d-galactosamine. The polysaccharide is modified with sulfate groups at different positions by a variety of sulfotransferases. CS chains exhibit various biological and pathological functions by interacting with cytokines and growth factors and regulating their signal transduction. The fine structure of the CS chain defines its specific biological roles. However, structural analysis of CS has been restricted to disaccharide analysis, hampering the understanding of the structure-function relationship of CS chains. Here, we chemo-enzymatically synthesized CS dodecasaccharides having various sulfate modifications using a bioreactor system of bacterial chondroitin polymerase mutants and various CS sulfotransferases. We developed a sequencing method for CS chains using the CS dodecasaccharides. The method consists of (i) labeling a reducing end with 2-aminopyridine (PA), (ii) partial digestion of CS with testicular hyaluronidase, followed by separation of PA-conjugated oligosaccharides with different chain lengths, (iii) limited digestion of these oligosaccharides with chondroitin lyase AC II into disaccharides, followed by labeling with 2-aminobenzamide, (iv) CS disaccharide analysis using a dual-fluorescence HPLC system (reversed-phase ion-pair and ion-exchange chromatography), and (v) estimation of the composition by calculating individual disaccharide ratios. This CS chain sequencing allows characterization of CS-modifying enzymes and provides a useful tool toward understanding the structure-function relationship of CS chains.
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Affiliation(s)
- Tatsumasa Shioiri
- Institute for Molecular Science of Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi 480-1195, Japan
| | - Jun Tsuchimoto
- Institute for Molecular Science of Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi 480-1195, Japan
| | - Hideto Watanabe
- Institute for Molecular Science of Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi 480-1195, Japan
| | - Nobuo Sugiura
- Institute for Molecular Science of Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi 480-1195, Japan
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12
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Suits MDL, Pluvinage B, Law A, Liu Y, Palma AS, Chai W, Feizi T, Boraston AB. Conformational analysis of the Streptococcus pneumoniae hyaluronate lyase and characterization of its hyaluronan-specific carbohydrate-binding module. J Biol Chem 2014; 289:27264-27277. [PMID: 25100731 PMCID: PMC4175358 DOI: 10.1074/jbc.m114.578435] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
For a subset of pathogenic microorganisms, including Streptococcus pneumoniae, the recognition and degradation of host hyaluronan contributes to bacterial spreading through the extracellular matrix and enhancing access to host cell surfaces. The hyaluronate lyase (Hyl) presented on the surface of S. pneumoniae performs this role. Using glycan microarray screening, affinity electrophoresis, and isothermal titration calorimetry we show that the N-terminal module of Hyl is a hyaluronan-specific carbohydrate-binding module (CBM) and the founding member of CBM family 70. The 1.2 Å resolution x-ray crystal structure of CBM70 revealed it to have a β-sandwich fold, similar to other CBMs. The electrostatic properties of the binding site, which was identified by site-directed mutagenesis, are distinct from other CBMs and complementary to its acidic ligand, hyaluronan. Dynamic light scattering and solution small angle x-ray scattering revealed the full-length Hyl protein to exist as a monomer/dimer mixture in solution. Through a detailed analysis of the small angle x-ray scattering data, we report the pseudoatomic solution structures of the monomer and dimer forms of the full-length multimodular Hyl.
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Affiliation(s)
- Michael D L Suits
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
| | - Benjamin Pluvinage
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
| | - Adrienne Law
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
| | - Yan Liu
- Glycosciences Laboratory, Imperial College London, Burlington Danes Building, Du Cane Road, London W12 0NN, United Kingdom, and
| | - Angelina S Palma
- Glycosciences Laboratory, Imperial College London, Burlington Danes Building, Du Cane Road, London W12 0NN, United Kingdom, and; REQUIMTE, Department of Chemistry, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Wengang Chai
- Glycosciences Laboratory, Imperial College London, Burlington Danes Building, Du Cane Road, London W12 0NN, United Kingdom, and
| | - Ten Feizi
- Glycosciences Laboratory, Imperial College London, Burlington Danes Building, Du Cane Road, London W12 0NN, United Kingdom, and
| | - Alisdair B Boraston
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada,.
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13
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Cerqueira C, Liu Y, Kühling L, Chai W, Hafezi W, van Kuppevelt TH, Kühn JE, Feizi T, Schelhaas M. Heparin increases the infectivity of Human Papillomavirus type 16 independent of cell surface proteoglycans and induces L1 epitope exposure. Cell Microbiol 2013; 15:1818-36. [PMID: 23601855 PMCID: PMC4731924 DOI: 10.1111/cmi.12150] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Revised: 03/20/2013] [Accepted: 04/11/2013] [Indexed: 12/15/2022]
Abstract
Human Papillomaviruses (HPVs) are the etiological agents of cervical cancer, and HPV-16 is the most prevalent type. Several HPVs require heparan sulfate proteoglycans (HSPGs) for cell binding. Here, we analyse the phenomenon that preincubation of HPV-16 with increasing concentrations of heparin results in partial restoration rather than more efficient inhibition of infection. While corroborating that the HSPGs are cell-binding receptors for HPV-16, heparin-preincubated virus bound to the extracellular matrix (ECM) via laminin-332. Furthermore, the interaction of virions with heparin, a representative of the highly sulfated S-domains of heparan sulfate (HS) chains of HSPGs, allowed HPV-16 infection in the absence of cell surface HSPGs. Therefore, we concluded that specific glycan moieties but not specific HSPG protein backbones are required for infection. The increased binding of an epitope-specific antibody to the viral capsid after heparin binding suggested that initial conformational changes in the HPV-16 virion occur during infection by interaction with'heparin-like' domains of cellular HSPGs. We propose that HS sequences with specific sulfation patterns are required to facilitate HPV-16 infection.
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Affiliation(s)
- Carla Cerqueira
- Emmy-Noether Group ‘Virus Endocytosis’, Institutes of Molecular Virology and Medical Biochemistry, University of Münster, Münster, Germany
| | - Yan Liu
- Glycosciences Laboratory, Imperial College London, United Kingdom
| | - Lena Kühling
- Emmy-Noether Group ‘Virus Endocytosis’, Institutes of Molecular Virology and Medical Biochemistry, University of Münster, Münster, Germany
| | - Wengang Chai
- Glycosciences Laboratory, Imperial College London, United Kingdom
| | - Wali Hafezi
- University Hospital Münster, Institute of Medical Microbiology – Clinical Virology, Münster, Germany
| | - Toin H. van Kuppevelt
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joachim E. Kühn
- University Hospital Münster, Institute of Medical Microbiology – Clinical Virology, Münster, Germany
| | - Ten Feizi
- Glycosciences Laboratory, Imperial College London, United Kingdom
| | - Mario Schelhaas
- Emmy-Noether Group ‘Virus Endocytosis’, Institutes of Molecular Virology and Medical Biochemistry, University of Münster, Münster, Germany
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14
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Eller S, Collot M, Yin J, Hahm HS, Seeberger PH. Automated Solid-Phase Synthesis of Chondroitin Sulfate Glycosaminoglycans. Angew Chem Int Ed Engl 2013; 52:5858-61. [DOI: 10.1002/anie.201210132] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Indexed: 11/09/2022]
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15
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Eller S, Collot M, Yin J, Hahm HS, Seeberger PH. Automatisierte Festphasensynthese von Chondroitinsulfatglycosaminoglycanen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201210132] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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16
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Micale N. Recent advances and perspectives on tropical diseases: Malaria. World J Transl Med 2012; 1:4-19. [DOI: 10.5528/wjtm.v1.i2.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Malaria remains a major health problem in the world. It is a neglected disease because it occurs almost exclusively in poor developing countries, which offer negligible marketable and profitable opportunities. Malaria (together with Tuberculosis), is responsible for an unprecedented global health crisis with devastating effects in developing countries. The 2011 Word Malaria Report indicated that 106 countries showed endemic malaria. Malaria control depends mainly on drug treatment, which is increasingly difficult due to the spread of drug resistant parasites and requires expensive drug combinations. Part of the inability to combat this disease is attributed to an incomplete understanding of its pathogenesis and pathophysiology. Improving the knowledge of the underlying pathogenic mechanisms of malaria transmission and of the exclusive metabolic pathways of the parasites (protozoa of the genus Plasmodium), should promote efficient treatment of disease and help the identification of novel targets for potential therapeutic interventions. Moreover, the elucidation of determinants involved in the spread of malaria will provide important information for efficient planning of strategies for targeted control.
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17
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Clausen TM, Christoffersen S, Dahlbäck M, Langkilde AE, Jensen KE, Resende M, Agerbæk MØ, Andersen D, Berisha B, Ditlev SB, Pinto VV, Nielsen MA, Theander TG, Larsen S, Salanti A. Structural and functional insight into how the Plasmodium falciparum VAR2CSA protein mediates binding to chondroitin sulfate A in placental malaria. J Biol Chem 2012; 287:23332-45. [PMID: 22570492 DOI: 10.1074/jbc.m112.348839] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Malaria is a major global health problem. Pregnant women are susceptible to infection regardless of previously acquired immunity. Placental malaria is caused by parasites capable of sequestering in the placenta. This is mediated by VAR2CSA, a parasite antigen that interacts with chondroitin sulfate A (CSA). One vaccine strategy is to block this interaction with VAR2CSA-specific antibodies. It is a priority to define a small VAR2CSA fragment that can be used in an adhesion blocking vaccine. In this, the obvious approach is to define regions of VAR2CSA involved in receptor binding. It has been shown that full-length recombinant VAR2CSA binds specifically to CSA with nanomolar affinity, and that the CSA-binding site lies in the N-terminal part of the protein. In this study we define the minimal binding region by truncating VAR2CSA and analyzing CSA binding using biosensor technology. We show that the core CSA-binding site lies within the DBL2X domain and parts of the flanking interdomain regions. This is in contrast to the idea that single domains do not possess the structural requirements for specific CSA binding. Small-angle x-ray scattering measurements enabled modeling of VAR2CSA and showed that the CSA-binding DBL2X domain is situated in the center of the structure. Mutating classic sulfate-binding sites in VAR2CSA, along with testing dependence of ionic interactions, suggest that the CSA binding is not solely dependent on the sulfated CSA structure. Based on these novel PfEMP1 structure-function studies, we have constructed a small VAR2CSA antigen that has the capacity to induce highly adhesion-blocking antibodies.
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Affiliation(s)
- Thomas M Clausen
- Department of Infectious Diseases, Centre for Medical Parasitology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.
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18
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Abstract
Background Plasmodium vivax infections seldom kill directly but do cause indirect mortality by reducing birth weight and causing abortion. Cytoadherence and sequestration in the microvasculature are central to the pathogenesis of severe Plasmodium falciparum malaria, but the contribution of cytoadherence to pathology in other human malarias is less clear. Methodology The adherence properties of P. vivax infected red blood cells (PvIRBC) were evaluated under static and flow conditions. Principal Findings P. vivax isolates from 33 patients were studied. None adhered to immobilized CD36, ICAM-1, or thrombospondin, putative ligands for P. falciparum vascular cytoadherence, or umbilical vein endothelial cells, but all adhered to immobilized chondroitin sulphate A (CSA) and hyaluronic acid (HA), the receptors for adhesion of P. falciparum in the placenta. PvIRBC also adhered to fresh placental cells (N = 5). Pre-incubation with chondroitinase prevented PvIRBC adherence to CSA, and reduced binding to HA, whereas preincubation with hyaluronidase prevented adherence to HA, but did not reduce binding to CSA significantly. Pre-incubation of PvIRBC with soluble CSA and HA reduced binding to the immobilized receptors and prevented placental binding. PvIRBC adhesion was prevented by pre-incubation with trypsin, inhibited by heparin, and reduced by EGTA. Under laminar flow conditions the mean (SD) shear stress reducing maximum attachment by 50% was 0.06 (0.02) Pa but, having adhered, the PvIRBC could then resist detachment by stresses up to 5 Pa. At 37°C adherence began approximately 16 hours after red cell invasion with maximal adherence at 30 hours. At 39°C adherence began earlier and peaked at 24 hours. Significance Adherence of P. vivax-infected erythrocytes to glycosaminoglycans may contribute to the pathogenesis of vivax malaria and lead to intrauterine growth retardation.
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19
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Engelhardt BE, Jordan MI, Srouji JR, Brenner SE. Genome-scale phylogenetic function annotation of large and diverse protein families. Genome Res 2011; 21:1969-80. [PMID: 21784873 PMCID: PMC3205580 DOI: 10.1101/gr.104687.109] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Accepted: 07/11/2011] [Indexed: 11/25/2022]
Abstract
The Statistical Inference of Function Through Evolutionary Relationships (SIFTER) framework uses a statistical graphical model that applies phylogenetic principles to automate precise protein function prediction. Here we present a revised approach (SIFTER version 2.0) that enables annotations on a genomic scale. SIFTER 2.0 produces equivalently precise predictions compared to the earlier version on a carefully studied family and on a collection of 100 protein families. We have added an approximation method to SIFTER 2.0 and show a 500-fold improvement in speed with minimal impact on prediction results in the functionally diverse sulfotransferase protein family. On the Nudix protein family, previously inaccessible to the SIFTER framework because of the 66 possible molecular functions, SIFTER achieved 47.4% accuracy on experimental data (where BLAST achieved 34.0%). Finally, we used SIFTER to annotate all of the Schizosaccharomyces pombe proteins with experimental functional characterizations, based on annotations from proteins in 46 fungal genomes. SIFTER precisely predicted molecular function for 45.5% of the characterized proteins in this genome, as compared with four current function prediction methods that precisely predicted function for 62.6%, 30.6%, 6.0%, and 5.7% of these proteins. We use both precision-recall curves and ROC analyses to compare these genome-scale predictions across the different methods and to assess performance on different types of applications. SIFTER 2.0 is capable of predicting protein molecular function for large and functionally diverse protein families using an approximate statistical model, enabling phylogenetics-based protein function prediction for genome-wide analyses. The code for SIFTER and protein family data are available at http://sifter.berkeley.edu.
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Affiliation(s)
- Barbara E Engelhardt
- Electrical Engineering and Computer Science Department, University of California, Berkeley, California 94720, USA.
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20
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Bielik AM, Zaia J. Multistage Tandem Mass Spectrometry of Chondroitin Sulfate and Dermatan Sulfate. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2011; 305:131-137. [PMID: 21860601 PMCID: PMC3158619 DOI: 10.1016/j.ijms.2010.10.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Chondroitin/dermatan sulfate (CS/DS) is a glycosaminoglycan (GAG) found in abundance in extracellular matrices. In connective tissue, CS/DS proteoglycans play structural roles in maintaining viscoelasticity through the large number of immobilized sulfate groups on CS/DS chains. CS/DS chains also bind protein families including growth factors and growth factor receptors. Through such interactions, CS/DS chains play important roles in neurobiochemical processes, connective tissue homeostasis, coagulation, and cell growth regulation. Expression of DS has been observed to increase in cancerous tissue relative to controls. In earlier studies, MS(2) was used to compare the types of CS/DS isomers present in biological samples. The results demonstrated that product ion abundances reflect the types of CS/DS repeats present and can be used quantitatively. It was not clear, however, to which of the CS/DS repeats the product ions abundances were sensitive. The present work explores the utility of MS(3) for structural characterization of CS/DS oligosaccharides. The data show that MS(3) product ion abundances correlate with the presence of DS-like repeats in specific positions on the oligosaccharide chains.
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Affiliation(s)
- Alicia M. Bielik
- Center for Biomedical Mass Spectrometry, Dept. of Biochemistry, Boston University, Boston, MA
| | - Joseph Zaia
- Center for Biomedical Mass Spectrometry, Dept. of Biochemistry, Boston University, Boston, MA
- Corresponding author, address: Boston University Medical Campus, 670 Albany St., Rm. 509, Boston, MA 02118, USA, (v) 1-617-638-6762, (f) 1-617-638-6761, (e)
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21
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Goel S, Gowda DC. How specific is Plasmodium falciparum adherence to chondroitin 4-sulfate? Trends Parasitol 2011; 27:375-81. [PMID: 21507719 DOI: 10.1016/j.pt.2011.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/16/2011] [Accepted: 03/19/2011] [Indexed: 11/16/2022]
Abstract
Plasmodium falciparum infection during pregnancy results in the sequestration of infected red blood cells (IRBCs) in the placenta, contributing to pregnancy associated malaria (PAM). IRBC adherence is mediated by the binding of a variant Plasmodium falciparum erythrocyte binding protein 1 named VAR2CSA to the low sulfated chondroitin 4-sulfate (C4S) proteoglycan (CSPG) present predominantly in the intervillous space of the placenta. IRBC binding is highly specific to the level and distribution of 4-sulfate groups in C4S. Given the strict specificity of IRBC-C4S interactions, it is better to use either placental CSPG or CSPGs bearing structurally similar C4S chains in defining VAR2CSA structural architecture that interact with C4S, evaluating VAR2CSA constructs for vaccine development or studying structure-based inhibitors as therapeutics for PAM.
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Affiliation(s)
- Suchi Goel
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, USA
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22
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Abstract
The glycosaminoglycans (GAGs) are linear polysaccharides expressed on animal cell surfaces and in extracellular matrices. Their biosynthesis is under complex control and confers a domain structure that is essential to their ability to bind to protein partners. Key to understanding the functions of GAGs are methods to determine accurately and rapidly patterns of sulfation, acetylation and uronic acid epimerization that correlate with protein binding or other biological activities. Mass spectrometry (MS) is particularly suitable for the analysis of GAGs for biomedical purposes. Using modern ionization techniques it is possible to accurately determine molecular weights of GAG oligosaccharides and their distributions within a mixture. Methods for direct interfacing with liquid chromatography have been developed to permit online mass spectrometric analysis of GAGs. New tandem mass spectrometric methods for fine structure determination of GAGs are emerging. This review summarizes MS-based approaches for analysis of GAGs, including tissue extraction and chromatographic methods compatible with LC/MS and tandem MS.
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Affiliation(s)
- Gregory O. Staples
- Center for Biomedical Mass Spectrometry, Dept. of Biochemistry, Boston University School of Medicine
| | - Joseph Zaia
- Center for Biomedical Mass Spectrometry, Dept. of Biochemistry, Boston University School of Medicine
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23
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Structural insights into chondroitin sulfate binding in pregnancy-associated malaria. Biochem Soc Trans 2010; 38:1337-41. [DOI: 10.1042/bst0381337] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Malaria during pregnancy is caused when parasite-infected erythrocytes accumulate within the placenta through interactions between the VAR2CSA protein on the infected erythrocyte surface and placental CSPGs (chondroitin sulfate proteoglycans). This interaction is the major target for therapeutics to treat or prevent pregnancy-associated malaria. Here we review the structural characterization of CSPG-binding DBL (Duffy-binding like) domains from VAR2CSA and summarize the growing evidence that the exquisite ligand specificity of VAR2CSA results from the adoption of higher-order architecture in which these domains fold together to form a ligand-binding pocket.
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24
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Ndam NT, Deloron P. Molecular aspects of Plasmodium falciparum Infection during pregnancy. J Biomed Biotechnol 2010; 2007:43785. [PMID: 17641725 PMCID: PMC1906705 DOI: 10.1155/2007/43785] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Accepted: 03/21/2007] [Indexed: 11/17/2022] Open
Abstract
Cytoadherence of Plasmodium-falciparum-parasitized red blood cells (PRBCs) to host receptors is the key phenomenon in the pathological process of the malaria disease. Some of these interactions can originate poor outcomes responsible for 1 to 3 million annual deaths mostly occurring among children in sub-Saharan Africa. Pregnancy-associated malaria (PAM) represents an important exception of the disease occurring at adulthood in malaria endemic settings. Consequences of this are shared between the mother (maternal anemia) and the baby (low birth weight and infant mortality). Demonstrating that parasites causing PAM express specific variant surface antigens (VSA(PAM)), including the P. falciparum erythrocyte membrane protein 1 (P f EMP1) variant VAR2CSA, that are targets for protective immunity has strengthened the possibility for the development of PAM-specific vaccine. In this paper, we review the molecular basis of malaria pathogenesis attributable to the erythrocyte stages of the parasites, and findings supporting potential anti-PAM vaccine components evidenced in PAM.
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Affiliation(s)
- Nicaise Tuikue Ndam
- UR 010, Laboratoire de Parasitologie, Institut de Recherche pour le Développement, Université Paris Descartes, IFR 71, 4 avenue de l'Observatoire, 75006 Paris, France
- *Nicaise Tuikue Ndam:
| | - Philippe Deloron
- UR 010, Laboratoire de Parasitologie, Institut de Recherche pour le Développement, Université Paris Descartes, IFR 71, 4 avenue de l'Observatoire, 75006 Paris, France
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25
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Singh K, Gitti RK, Diouf A, Zhou H, Gowda DC, Miura K, Ostazeski SA, Fairhurst RM, Garboczi DN, Long CA. Subdomain 3 of Plasmodium falciparum VAR2CSA DBL3x is identified as a minimal chondroitin sulfate A-binding region. J Biol Chem 2010; 285:24855-62. [PMID: 20529864 DOI: 10.1074/jbc.m110.118612] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Molecular interactions between the VAR2CSA protein, expressed on the surface of Plasmodium falciparum-infected erythrocytes, and placental chondroitin sulfate A (CSA) are primarily responsible for pregnancy-associated malaria (PAM). Interrupting these interactions may prevent or ameliorate the severity of PAM. Several of the Duffy binding-like (DBL) domains of VAR2CSA, including the DBL3x domain, have been shown to bind CSA in vitro, but a more detailed understanding of how DBL domains bind CSA is needed. In this study, we demonstrate that subdomain 3 (S3), one of the three subdomains of VAR2CSA DBL3x by itself, is the major contributor toward CSA binding. NMR spectroscopy and flow cytometry analyses show that S3 and the intact DBL3x domain bind CSA similarly. Mutations within the S3 portion of DBL3x markedly affect CSA binding. Both recombinant molecules, S3 and DBL3x, are recognized by antibodies in the plasma of previously pregnant women living in malaria-endemic regions of Mali, but much less so by plasma from men of the same regions. As the S3 sequence is highly conserved in all known VAR2CSA proteins expressed by different parasite isolates obtained from various malaria endemic areas of the world, the identification of S3 as an independent CSA-binding region provides a compelling molecular basis for designing interventions against PAM.
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Affiliation(s)
- Kavita Singh
- Structural Biology Section, Research Technologies Branch, NIAID, National Institutes of Health, Rockville, Maryland 20852, USA.
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26
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Kakizaki I, Ibori N, Kojima K, Yamaguchi M, Endo M. Mechanism for the hydrolysis of hyaluronan oligosaccharides by bovine testicular hyaluronidase. FEBS J 2010; 277:1776-86. [DOI: 10.1111/j.1742-4658.2010.07600.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Khunrae P, Philip JMD, Bull DR, Higgins MK. Structural comparison of two CSPG-binding DBL domains from the VAR2CSA protein important in malaria during pregnancy. J Mol Biol 2009; 393:202-13. [PMID: 19695262 PMCID: PMC3778748 DOI: 10.1016/j.jmb.2009.08.027] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 08/11/2009] [Indexed: 11/26/2022]
Abstract
Severe malaria during pregnancy is associated with accumulation of parasite-infected erythrocytes in the placenta due to interactions between VAR2CSA protein, expressed on the surface of infected-erythrocytes, and placental chondroitin sulfate proteoglycans (CSPG). VAR2CSA contains multiple CSPG-binding domains, including DBL3X and DBL6ɛ. Previous structural studies of DBL3X suggested CSPG to bind to a positively charged patch and sulfate-binding site on the concave surface of the domain. Here we present the structure of the DBL6ɛ domain from VAR2CSA. This domain displays the same overall architecture and secondary structure as that of DBL3X but differs in loop structures, disulfide bond positions and surface charge distribution. In particular, despite binding to CSPG, DBL6ɛ lacks the key features of the CSPG-binding site of DBL3X. Instead DBL6ɛ binds to CSPG through a positively charged surface on the distal side of subdomain 2 that is exposed in intact VAR2CSA on the erythrocyte surface. Finally, unlike intact VAR2CSA, both DBL3X and DBL6ɛ bind to various carbohydrates, with greatest affinity for ligands with high sulfation and negative charge. These studies provide further insight into the structure of DBL domains and suggest a model for the role of individual domains in CSPG binding by VAR2CSA in placental malaria.
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Affiliation(s)
- Pongsak Khunrae
- Department of Biochemistry, University of Cambridge, 80, Tennis Court Road, Cambridge CB2 1GA, UK
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28
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Goyal A, Goel S, Gowda DC. Plasmodium falciparum: Assessment of parasite-infected red blood cell binding to placental chondroitin proteoglycan and bovine tracheal chondroitin sulfate A. Exp Parasitol 2009; 123:105-10. [PMID: 19508868 DOI: 10.1016/j.exppara.2009.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Revised: 05/19/2009] [Accepted: 06/04/2009] [Indexed: 11/25/2022]
Abstract
In pregnant women infected with Plasmodium falciparum, the infected red blood cells (IRBCs) sequester in placenta by binding to the chondroitin 4-sulfate (C4S) chains of low sulfated chondroitin sulfate proteoglycan (CSPG). Placental CSPG, the natural receptor for IRBC adherence in the placenta, is the ideal molecule for studying structural interactions in IRBC adhesion to C4S, adhesion inhibitory antibody responses, and identification of parasite adhesive protein(s). However, because of difficulty involved in purifying placental CSPG, the commercially available bovine tracheal chondroitin sulfate A (bCSA), a copolymer having structural features of both C4S and C6S, has been widely used. To determine the validity of bCSA for C4S-IRBC interaction studies, we comparatively evaluated the characteristics of IRBC binding to placental CSPG and bCSA using three commonly used parasite strains. The results indicate that, in all three parasites studied, the characteristics of IRBC binding to placental CSPG and bCSA are qualitatively similar, but the binding capacity with respect to both the number of IRBCs bound per unit area of coated surface and binding strength is significantly higher for CSPG than bCSA regardless of whether parasites were selected on CSPG or bCSA. These results demonstrate that placental CSPG is best suited for studying interactions between parasite adhesive protein(s) and C4S, and have implications in understanding C4S-IRBC structural interactions.
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Affiliation(s)
- Atul Goyal
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, 17033, USA
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29
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Achur RN, Kakizaki I, Goel S, Kojima K, Madhunapantula SV, Goyal A, Ohta M, Kumar S, Takagaki K, Gowda DC. Structural interactions in chondroitin 4-sulfate mediated adherence of Plasmodium falciparum infected erythrocytes in human placenta during pregnancy-associated malaria. Biochemistry 2009; 47:12635-43. [PMID: 18975976 DOI: 10.1021/bi801643m] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Infection with Plasmodium falciparum during pregnancy results in the adherence of infected red blood cells (IRBCs) in placenta, causing pregnancy-associated malaria with severe health complications in mothers and fetuses. The chondroitin 4-sulfate (C4S) chains of very low sulfated chondroitin sulfate proteoglycans (CSPGs) in placenta mediate the IRBC adherence. While it is known that partially sulfated but not fully sulfated C4S effectively binds IRBCs, structural interactions involved remain unclear and are incompletely understood. In this study, structurally defined C4S oligosaccharides of varying sulfate contents and sizes were evaluated for their ability to inhibit the binding of IRBCs from different P. falciparum strains to CSPG purified from placenta. The results clearly show that, with all parasite strains studied, dodecasaccharide is the minimal chain length required for the efficient adherence of IRBCs to CSPG and two 4-sulfated disaccharides within this minimal structural motif are sufficient for maximal binding. Together, these data demonstrate for the first time that the C4S structural requirement for IRBC adherence is parasite strain-independent. We also show that the carboxyl group on nonreducing end glucuronic acid in dodecasaccharide motif is important for IRBC binding. Thus, in oligosaccharides containing terminal 4,5-unsaturated glucuronic acid, the nonreducing end disaccharide moiety does not interact with IRBCs due to the altered spatial orientation of carboxyl group. In such C4S oligosaccharides, 14-mer but not 12-mer constitutes the minimal motif for inhibition of IRBC binding to placental CSPG. These data have important implications for the development and evaluation of therapeutics and vaccine for placental malaria.
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Affiliation(s)
- Rajeshwara N Achur
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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30
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Hot, sweet and sticky: the glycobiology of Plasmodium falciparum. Trends Parasitol 2008; 24:210-8. [DOI: 10.1016/j.pt.2008.02.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 02/02/2008] [Accepted: 02/05/2008] [Indexed: 11/22/2022]
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31
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Hitchcock AM, Yates KE, Costello CE, Zaia J. Comparative glycomics of connective tissue glycosaminoglycans. Proteomics 2008; 8:1384-97. [PMID: 18318007 DOI: 10.1002/pmic.200700787] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Homeostasis of connective joint tissues depends on the maintenance of an extracellular matrix, consisting of an integrated assembly of collagens, glycoproteins, proteoglycans, and glycosaminoglycans (GAGs). Isomeric chondroitin sulfate (CS) glycoforms differing in position and degree of sulfation and uronic acid epimerization play specific and distinct functional roles during development and disease onset. This work profiles the CS epitopes expressed by different joint tissues as a function of age and osteoarthritis. GAGs were extracted from joint tissues (cartilage, tendon, ligment, muscle, and synovium) and partially depolymerized using chondroitinase enzymes. The oligosaccharide products were differentially stable isotope labeled by reductive amination using 2-anthranilic acid-d(0) or -d(4) and subjected to amide-hydrophilic interaction chromatography (HILIC) online LC-MS/MS. The analysis presented herein enables simultaneous profiling of the expression of nonreducing end, linker region, and Delta-unsaturated interior oligosaccharide domains of the CS chains among the different joint tissues. The results provide important new information on the changes to the expression of CS GAG chains during disease and development.
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Affiliation(s)
- Alicia M Hitchcock
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
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Achur RN, Muthusamy A, Madhunapantula SV, Gowda DC. Binding affinity of Plasmodium falciparum-infected erythrocytes from infected placentas and laboratory selected strains to chondroitin 4-sulfate. Mol Biochem Parasitol 2008; 159:79-84. [PMID: 18359524 DOI: 10.1016/j.molbiopara.2008.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 02/05/2008] [Accepted: 02/07/2008] [Indexed: 11/26/2022]
Abstract
The adherence of Plasmodium falciparum-infected red blood cells (IRBCs) in human placenta is mediated by chondroitin 4-sulfate (C4S). The C4S-adherent parasites selected from laboratory strains have been widely used for determining the C4S structural elements involved in IRBC binding and for the identification of parasite adhesive protein(s). However, as far as we know, the relative binding strength of the placental versus laboratory-selected parasites has not been reported. In this study, we show that IRBCs from the infected placentas bind to C4S about 3-fold higher than those selected for C4S adherence from laboratory strains. Although adherent parasites selected from several laboratory strains have comparable binding strengths, the one obtained from 3D7 parasites designated as 3D7N61 used for malaria genome sequencing, exhibits markedly lower binding strength. Furthermore, 3D7N61-CSA parasites lose most of the binding capacity by tenth generation in continuous culture.
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Affiliation(s)
- Rajeshwara N Achur
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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Beeson JG, Andrews KT, Boyle M, Duffy MF, Choong EK, Byrne TJ, Chesson JM, Lawson AM, Chai W. Structural Basis for Binding of Plasmodium falciparum Erythrocyte Membrane Protein 1 to Chondroitin Sulfate and Placental Tissue and the Influence of Protein Polymorphisms on Binding Specificity. J Biol Chem 2007; 282:22426-36. [PMID: 17562715 DOI: 10.1074/jbc.m700231200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chondroitin sulfate (CS) A is a key receptor for adhesion of Plasmodium falciparum-infected erythrocytes (IEs) in the placenta and can also mediate adhesion to microvascular endothelial cells. IEs that adhere to CSA express var2csa-type genes, which encode specific variants of the IE surface antigen P. falciparum erythrocyte membrane protein 1 (PfEMP1). We report direct binding of native PfEMP1, isolated from IEs and encoded by var2csa, to immobilized CSA. Binding of PfEMP1 was dependent on 4-O-sulfated disaccharides and glucuronic acid rather than iduronic acid, consistent with the specificity of intact IEs. Using immobilized CS oligosaccharides as neoglycolipid probes, the minimum chain length for direct binding of PfEMP1 was eight monosaccharide units. Similarly for IE adhesion to placental tissue there was a requirement for 4-O-sulfated GalNAc and glucuronic acid mixed with non-sulfated disaccharides; 6-O-sulfation interfered with the interaction between placental CSA and IEs. The minimum chain length for maximal inhibition of adhesion was 10 monosaccharide residues. Partially 4-O-sulfated CS oligosaccharides (45-55% sulfation) were highly effective inhibitors of placental adhesion (IC(50), 0.15 microg/ml) and may have potential for therapeutic development. We used defined P. falciparum isolates expressing different variants of var2csa in adhesion assays and found that there were isolate-specific differences in the preferred structural motifs for adhesion to CSA that correlated with polymorphisms in PfEMP1 encoded by var2csa-type genes. This may influence sites of IE sequestration or parasite virulence. These findings have significant implications for understanding the pathogenesis and biology of malaria, particularly during pregnancy, and the development of targeted interventions.
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Affiliation(s)
- James G Beeson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3050, Australia.
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Muthusamy A, Achur RN, Valiyaveettil M, Botti JJ, Taylor DW, Leke RF, Gowda DC. Chondroitin sulfate proteoglycan but not hyaluronic acid is the receptor for the adherence of Plasmodium falciparum-infected erythrocytes in human placenta, and infected red blood cell adherence up-regulates the receptor expression. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:1989-2000. [PMID: 17525266 PMCID: PMC1899447 DOI: 10.2353/ajpath.2007.061238] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A low-sulfated chondroitin sulfate proteoglycan (CSPG) has been shown to be the receptor for the adherence of Plasmodium falciparum-infected red blood cells (IRBCs) in human placenta. Recently, hyaluronic acid (HA) has been suggested as an additional receptor even though IRBC binding to HA and the presence of HA at locations where IRBCs adhere in the placenta have not been established. In this study, we investigated whether HA is also a receptor for IRBC binding. IRBCs from infected placentas as well as those from different laboratory strains could bind to CSPG but not to HA. In a cell depletion assay, IRBCs from infected placentas could bind quantitatively to CSPG. Although CSPG is present both in the intervillous space and on the syncytiotrophoblast surface, HA is absent in these locations. These data conclusively demonstrate that CSPG, but not HA, is a receptor for IRBC adherence in the placenta. Our data also show, for the first time, that the IRBC-binding CSPG in the placenta is of fetal origin and that, in P. falciparum-infected placentas, the CSPG level is significantly increased, which could exacerbate IRBC adherence and placental pathogenesis. These results have important implications for the development of anti-IRBC adhesion-based vaccine for pregnancy-associated malaria.
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Affiliation(s)
- Arivalagan Muthusamy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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Abstract
In the century since the discovery of the ABO blood groups, numerous associations between ABO groups and disease have been noted. However, the selection pressures defining the ABO distributions remain uncertain. We review published information on Plasmodium falciparum infection and ABO blood groups. DNA sequence information dates the emergence and development of the group O allele to a period of evolution before human migration out of Africa, concomitant with P falciparum's activity. The current geographic distribution of group O is also consistent with a selection pressure by P falciparum in favor of group O individuals in malaria-endemic regions. We critically review clinical reports of ABO and P falciparum infection, documenting a correlation between disease severity and ABO group. Finally, we review published data on the pathogenesis of P falciparum infection, and propose a biologic model to summarize the role of ABO blood groups in cytoadherence biology. Such ABO-related mechanisms also point to a new hypothesis to account for selection of the Le(a-b-) phenotype. Taken together, a broad range of available evidence suggests that the origin, distribution, and relative proportion of ABO blood groups in humans may have been directly influenced by selective genetic pressure from P falciparum infection.
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Affiliation(s)
- Christine M Cserti
- University Health Network, Toronto General Hospital (Blood Transfusion Laboratory), Toronto, Ontario, Canada.
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36
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Gowda DC. Role of chondroitin-4-sulfate in pregnancy-associated malaria. ADVANCES IN PHARMACOLOGY 2007; 53:375-400. [PMID: 17239776 DOI: 10.1016/s1054-3589(05)53018-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- D Channe Gowda
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine Hershey, Pennsylvania 17033, USA
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Sugiura N, Shimokata S, Watanabe H, Kimata K. MS analysis of chondroitin polymerization: effects of Mn2+ ions on the stability of UDP-sugars and chondroitin synthesis. Anal Biochem 2007; 365:62-73. [PMID: 17395146 DOI: 10.1016/j.ab.2007.02.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 02/12/2007] [Accepted: 02/19/2007] [Indexed: 12/01/2022]
Abstract
Chondroitin polymerase from Escherichia coli strain K4 (K4CP) synthesizes chondroitin (CH) polysaccharides by the alternate addition of N-acetyl-D-galactosamine (GalNAc) and D-glucuronic acid (GlcA) to acceptor CH oligosaccharides in the presence of Mn(2+) ions. In this study, we applied matrix-assisted laser desorption ionization and time-of-flight mass spectrometry (MALDI-TOF MS) for the further characterization of the products synthesized by K4CP from CH hexasaccharide as an initial acceptor and UDP-GalNAc and UDP-GlcA as donors. The analysis identified individual CH chains of various lengths and enabled the calculation of their average molecular weights. The ion peaks of the CH chains synthesized in the short-time reactions demonstrated not only the alternate addition of GlcA and GalNAc but also the more frequent transfer of GlcA and GalNAc, consistent with our previous kinetic data. In contrast, the MS spectra of the chains synthesized in the long-time reaction showed that CH chains containing GalNAc at the nonreducing ends were more abundant than those containing GlcA. We found that this inconsistency was due to the preferential decomposition of UDP-GlcA by Mn(2+) ions. We defined the optimal conditions to yield further elongation of the CH chains that have nearly equal numbers of GlcA and GalNAc residues at the nonreducing ends.
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Affiliation(s)
- Nobuo Sugiura
- Institute for Molecular Science of Medicine, Aichi Medical University, Yazako, Nagakute, Aichi 480-1195, Japan
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38
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Baratin M, Roetynck S, Pouvelle B, Lemmers C, Viebig NK, Johansson S, Bierling P, Scherf A, Gysin J, Vivier E, Ugolini S. Dissection of the role of PfEMP1 and ICAM-1 in the sensing of Plasmodium-falciparum-infected erythrocytes by natural killer cells. PLoS One 2007; 2:e228. [PMID: 17311092 PMCID: PMC1794133 DOI: 10.1371/journal.pone.0000228] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Accepted: 01/25/2007] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Host innate immunity contributes to malaria clinical outcome by providing protective inflammatory cytokines such as interferon-gamma, and by shaping the adaptive immune response. Plasmodium falciparum (Pf) is the etiologic agent of the most severe forms of human malaria. Natural Killer (NK) cells are lymphocytes of the innate immune system that are the first effectors to produce interferon-gamma in response to Pf. However, the molecular bases of Pf-NK cell recognition events are unknown. Our study focuses on the role of Pf erythrocyte membrane protein 1 (PfEMP1), a major Pf virulence factor. PfEMP1 is expressed on parasitized-erythrocytes and participates to vascular obstruction through the binding to several host receptors. PfEMP1 is also a pivotal target for host antibody response to Pf infection. METHODOLOGY/PRINCIPAL FINDINGS Using genetically-engineered parasite mutant strains, a human genetic deficiency, and blocking antibodies, we identified two receptor-ligand pairs involved in two uncoupled events occurring during the sensing of Pf infection by NK cells. First, PfEMP1 interaction with one of its host receptor, chondroitin sulfate A, mediates the cytoadhesion of Pf-infected erythrocytes to human NK cell lines, but is not required for primary NK cell activation. Second, intercellular adhesion molecule-1 (ICAM-1), another host receptor for PfEMP1, is mandatory for NK cell interferon-gamma response. In this case, ICAM-1 acts via its engagement with its host ligand, LFA-1, and not with PfEMP1, consistent with the obligatory cross-talk of NK cells with macrophages for their production of interferon-gamma. CONCLUSION/SIGNIFICANCE PfEMP1-independent but ICAM-1/LFA-1-dependent events occurring during NK cell activation by Pf highlight the fundamental role of cellular cooperation during innate immune response to malaria.
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Affiliation(s)
- Myriam Baratin
- Aix-Marseille Université, Faculté des Sciences de Luminy, Centre d'Immunologie de Marseille-Luminy (CIML), Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, Marseille, France
- Centre National de la Recherche Scientifique (CNRS), UMR6102, Marseille, France
| | - Sophie Roetynck
- Aix-Marseille Université, Faculté des Sciences de Luminy, Centre d'Immunologie de Marseille-Luminy (CIML), Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, Marseille, France
- Centre National de la Recherche Scientifique (CNRS), UMR6102, Marseille, France
| | - Bruno Pouvelle
- Unité de Parasitologie Expérimentale, Université de la Méditerranée, Marseille, France
| | - Céline Lemmers
- Aix-Marseille Université, Faculté des Sciences de Luminy, Centre d'Immunologie de Marseille-Luminy (CIML), Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, Marseille, France
- Centre National de la Recherche Scientifique (CNRS), UMR6102, Marseille, France
| | - Nicola K. Viebig
- Institut Pasteur and Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Sofia Johansson
- Aix-Marseille Université, Faculté des Sciences de Luminy, Centre d'Immunologie de Marseille-Luminy (CIML), Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, Marseille, France
- Centre National de la Recherche Scientifique (CNRS), UMR6102, Marseille, France
| | | | - Artur Scherf
- Institut Pasteur and Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Jürg Gysin
- Unité de Parasitologie Expérimentale, Université de la Méditerranée, Marseille, France
| | - Eric Vivier
- Aix-Marseille Université, Faculté des Sciences de Luminy, Centre d'Immunologie de Marseille-Luminy (CIML), Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, Marseille, France
- Centre National de la Recherche Scientifique (CNRS), UMR6102, Marseille, France
- Hôpital de la Conception, Assistance Publique – Hôpitaux de Marseille, France
- * To whom correspondence should be addressed. E-mail: (SU); (EV)
| | - Sophie Ugolini
- Aix-Marseille Université, Faculté des Sciences de Luminy, Centre d'Immunologie de Marseille-Luminy (CIML), Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, Marseille, France
- Centre National de la Recherche Scientifique (CNRS), UMR6102, Marseille, France
- * To whom correspondence should be addressed. E-mail: (SU); (EV)
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Gowda ASP, Madhunapantula SV, Achur RN, Valiyaveettil M, Bhavanandan VP, Gowda DC. Structural basis for the adherence of Plasmodium falciparum-infected erythrocytes to chondroitin 4-sulfate and design of novel photoactivable reagents for the identification of parasite adhesive proteins. J Biol Chem 2006; 282:916-28. [PMID: 17085451 DOI: 10.1074/jbc.m604741200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A dodecasaccharide motif of the low-sulfated chondroitin 4-sulfate (C4S) mediate the binding of Plasmodium falciparum-infected red blood cells (IRBCs) in human placenta. Here we studied the detailed C4S structural requirements by assessing the ability of chemically modified C4S to inhibit IRBC binding to the placental chondroitin sulfate proteoglycan. Replacement of the N-acetyl groups with bulky N-acyl or N-benzoyl substituents had no effect on the inhibitory activity of C4S, whereas reduction of the carboxyl groups abrogated the activity. Dermatan sulfates showed approximately 50% inhibitory activity when compared with C4Ss with similar sulfate contents. These data demonstrate that the C4S carboxyl groups and their equatorial orientation but not the N-acetyl groups are critical for IRBC binding. Conjugation of bulky substituents to the reducing end N-acetylgalactosamine residues of C4S dodecasaccharide had no effect on its inhibitory activity. Based on these results, we prepared photoaffinity reagents for the identification of the parasite proteins involved in C4S binding. Cross-linking of the IRBCs with a radioiodinated photoactivable C4S dodecasaccharide labeled a approximately 22-kDa novel parasite protein, suggesting strongly for the first time that a low molecular weight IRBC surface protein rather than a 200-400-kDa PfEMP1 is involved in C4S binding. Conjugation of biotin to the C4S dodecasaccharide photoaffinity probe afforded a strategy for the isolation of the labeled protein by avidin affinity precipitation, facilitating efforts to identify the C4S-adherent IRBC protein(s). Our results also have broader implications for designing oligosaccharide-based photoaffinity probes for the identification of proteins involved in glycosaminoglycan-dependent attachment of microbes to hosts.
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Affiliation(s)
- A S Prakasha Gowda
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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40
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Achur RN, Agbor-Enoh ST, Gowda DC. Rat spongiotrophoblast-specific protein is predominantly a unique low sulfated chondroitin sulfate proteoglycan. J Biol Chem 2006; 281:32327-34. [PMID: 16954212 DOI: 10.1074/jbc.m605841200] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have previously demonstrated that the human placenta contains a uniquely low sulfated extracellular aggrecan family chondroitin sulfate proteoglycan (CSPG). This CSPG is a major receptor for the adherence of Plasmodium falciparum-infected red blood cells (IRBCs) in placentas, causing pregnancy-specific malaria. However, it is not known whether such low sulfated CSPGs occur in placentas of other animals and, if so, whether IRBCs bind to those CSPGs. In this study, we show that rat placenta contains a uniquely low sulfated extracellular CSPG bearing chondroitin sulfate (CS) chains, which comprise only approximately 2% 4-sulfated and the remainder nonsulfated disaccharides. Surprisingly, the core protein of the rat placental CSPG, unlike that of the human placental CSPG, is a spongiotrophoblast-specific protein (SSP), which is expressed in a pregnancy stage-dependent manner. The majority of rat placental SSP is present in the CSPG form, and only approximately 10% occurs without CS chain substitution. Of the total SSP-CSPG in rat placenta, approximately 57% is modified with a single CS chain, and approximately 43% carries two CS chains. These data together with the previous finding on human placental CSPG suggest that the expression of low sulfated CSPG is a common feature of animal placentas. Our data also show that the unique species-specific difference in the biology of the rat and human placentas is reflected in the occurrence of completely different CSPG core protein types. Furthermore, the rat SSP-CSPG binds P. falciparum IRBCs in a CS chain-dependent manner. Since IRBCs have been reported to accumulate in the placentas of malaria parasite-infected rodents, our results have important implications for exploiting pregnant rats as a model for studying chondroitin 4-sulfate-based therapeutics for human placental malaria.
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Affiliation(s)
- Rajeshwara N Achur
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033-0850, USA
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41
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Lucchi NW, Koopman R, Peterson DS, Moore JM. Plasmodium falciparum-infected Red Blood Cells Selected for Binding to Cultured Syncytiotrophoblast Bind to Chondroitin Sulfate A and Induce Tyrosine Phosphorylation in the Syncytiotrophoblast. Placenta 2006; 27:384-94. [PMID: 16009422 DOI: 10.1016/j.placenta.2005.04.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2005] [Revised: 04/24/2005] [Accepted: 04/25/2005] [Indexed: 11/23/2022]
Abstract
An important pathogenic complication of malaria during human pregnancy is sequestration of Plasmodium-infected red blood cells (iRBCs) in the placental intervillous spaces. This sequestration is thought to be mediated in part by binding of the iRBCs to receptors expressed on the syncytiotrophoblast (ST) membrane. We report here the use of a dynamic system to study the consequences of this cytoadherence on ST function using human syncytiotrophoblast and the choriocarcinoma cell line, BeWo. Laboratory isolates of Plasmodium falciparum were selected for their ability to bind to ST and used to investigate binding-induced cellular changes in the ST. Treatment of the ST cells with chondroitinase ABC suggested that the selected parasites bind predominantly to chondroitin sulfate A, but other receptors for parasite binding may be involved. Intracellular signaling in the ST induced by iRBCs binding was investigated by assessing tyrosine phosphorylation of ST proteins following iRBC binding. We demonstrate for the first time that iRBC cytoadherence to syncytiotrophoblast enhances tyrosine phosphorylation of a series of proteins in these cells. This approach will be useful in further studies of ST function in the malaria-infected placenta, the dynamics of selection of syncytiotrophoblast-binding parasites, and the identification of new receptors for parasite cytoadherence in the placenta.
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Affiliation(s)
- N W Lucchi
- Department of Infectious Diseases, College of Veterinary Medicine and Center for Tropical and Emerging Global Diseases, Medical Microbiology and Parasitology, 501 DW Brooks Dr, University of Georgia, Athens, GA 30602, USA
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Miller MJC, Costello CE, Malmström A, Zaia J. A tandem mass spectrometric approach to determination of chondroitin/dermatan sulfate oligosaccharide glycoforms. Glycobiology 2006; 16:502-13. [PMID: 16489125 PMCID: PMC2577607 DOI: 10.1093/glycob/cwj093] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Dermatan sulfate (DS) chains are variants of chondroitin sulfate (CS) that are expressed in mammalian extracellular matrices and are particularly prevalent in skin. DS has been implicated in varied biological processes including wound repair, infection, cardiovascular disease, tumorigenesis, and fibrosis. The biological activities of DS have been attributed to its high content of IdoA(alpha1-3)GalNAc4S(beta1-4) disaccharide units. Mature CS/DS chains consist of blocks with high and low GlcA/IdoA ratios, and sulfation may occur at the 4- and/or 6-position of GalNAc and 2-position of IdoA. Traditional methods for the analysis of CS/DS chains involve differential digestion with specific chondroitinases followed by steps of chromatographic isolation of the products and di-saccharide analysis on the individual fraction. This work reports the use of tandem mass spectrometry to determine the patterns of sulfation and epimerization of CS/DS oligosaccharides in a single step. The approach is first validated and then applied to a series of skin DS samples and to decorins from three different tissues. DS samples ranged from 74 to 99% of CSB-like repeats, using this approach. Decorin samples ranged from 30% CSB-like repeats for those samples from articular cartilage to 75% for those from sclera. These values agree with known levels of glucuronyl C5-epimerase in these tissues.
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Affiliation(s)
- May Joy C Miller
- Department of Biochemistry, Boston University School of Medicine, 715 Albany Street, R-806, Boston, MA 02118, USA
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Beeson JG, Duffy PE. The immunology and pathogenesis of malaria during pregnancy. Curr Top Microbiol Immunol 2006; 297:187-227. [PMID: 16265906 DOI: 10.1007/3-540-29967-x_6] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Women in endemic areas become highly susceptible to malaria during first and second pregnancies, despite immunity acquired after years of exposure. Recent insights have advanced our understanding of pregnancy malaria caused by Plasmodium falciparum, which is responsible for the bulk of severe disease and death. Accumulation of parasitized erythrocytes in the blood spaces of the placenta is a key feature of maternal infection with P. falciparum. Placental parasites express surface ligands and antigens that differ from those of other P. falciparum variants, facilitating evasion of existing immunity, and mediate adhesion to specific molecules, such as chondroitin sulfate A, in the placenta. The polymorphic and clonally variant P. falciparum erythrocyte membrane protein 1, encoded by var genes, binds to placental receptors in vitro and may be the target of protective antibodies. An intense infiltration of immune cells, including macrophages, into the placental intervillous spaces, and the production of pro-inflammatory cytokines often occur in response to infection, and are associated with low birth weight and maternal anemia. Expression of alpha and beta chemokines may initiate or facilitate this cellular infiltration during placental malaria. Specific immunity against placental-binding parasites may prevent infection or facilitate clearance of parasites prior to the influx of inflammatory cells, thereby avoiding a cascade of events leading to disease and death. Much less is known about pathogenic processes in P. vivax infections, and corresponding immune responses. Emerging knowledge of the pathogenesis and immunology of malaria in pregnancy will increasingly lead to new opportunities for the development of therapeutic and preventive interventions and new tools for diagnosis and monitoring.
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Affiliation(s)
- J G Beeson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
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Prabhakar V, Sasisekharan R. The biosynthesis and catabolism of galactosaminoglycans. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2006; 53:69-115. [PMID: 17239763 DOI: 10.1016/s1054-3589(05)53005-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Vikas Prabhakar
- Division of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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45
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Andrews KT, Klatt N, Adams Y, Mischnick P, Schwartz-Albiez R. Inhibition of chondroitin-4-sulfate-specific adhesion of Plasmodium falciparum-infected erythrocytes by sulfated polysaccharides. Infect Immun 2005; 73:4288-94. [PMID: 15972521 PMCID: PMC1168624 DOI: 10.1128/iai.73.7.4288-4294.2005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Adhesion of Plasmodium falciparum-infected erythrocytes to placental chondroitin 4-sulfate (CSA) has been linked to the severe disease outcome of pregnancy-associated malaria. Soluble polysaccharides that release mature-stage parasitized erythrocytes into the peripheral circulation may help elucidate these interactions and have the potential to aid in developing therapeutic strategies. We have screened a panel of 11 sulfated polysaccharides for their capacities to inhibit adhesion of infected erythrocytes to CSA expressed on CHO-K1 cells and ex vivo human placental tissue. Two carrageenans and a cellulose sulfate (CS10) were able to inhibit adhesion to CSA and to cause already bound infected erythrocytes to de-adhere in a dose-dependent manner. CS10, like CSA and in contrast to all other compounds tested, remained bound to infected erythrocytes after washing and continued to inhibit binding. Both carrageenans and CS10 inhibited adhesion to placental tissue. Although highly sulfated dextran sulfate can inhibit CSA-mediated adhesion to CHO cells, this polysaccharide amplified adhesion to placental tissue severalfold, demonstrating the importance of evaluating inhibitory compounds in systems as close to in vivo as possible. Interestingly, and in contrast to all other compounds tested, which had a random distribution of sulfate groups, CS10 exhibited a clustered sulfate pattern along the polymer chain, similar to that of the undersulfated placental CSA preferred by placental-tissue-binding infected erythrocytes. Therefore, the specific anti-adhesive capacity observed here seems to depend not only on the degree of charge and sulfation but also on a particular pattern of sulfation.
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Affiliation(s)
- Katherine T Andrews
- The Australian Centre for International and Tropical Health and Nutrition, Infectious Diseases and Immunology Division, Queensland Institute of Medical Research, Royal Brisbane Hospital, Herston, Australia.
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Achur RN, Muthusamy A, Madhunapantula SV, Bhavanandan VP, Seudieu C, Channe Gowda D. Chondroitin sulfate proteoglycans of bovine cornea: structural characterization and assessment for the adherence of Plasmodium falciparum-infected erythrocytes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1701:109-19. [PMID: 15450180 DOI: 10.1016/j.bbapap.2004.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2004] [Revised: 05/27/2004] [Accepted: 06/17/2004] [Indexed: 10/26/2022]
Abstract
The structures of the bovine corneal chondroitin sulfate (CS) chains and the nature of core proteins to which these chains are attached have not been studied in detail. In this study, we show that structurally diverse CS chains are present in bovine cornea and that they are mainly linked to decorin core protein. DEAE-Sephacel chromatography fractionated the corneal chondroitin sulfate proteoglycans (CSPGs) into three distinct fractions, CSPG-I, CSPG-II, and CSPG-III. These CSPGs markedly differ in their CS and dermatan sulfate (DS) contents, and in particular the CS structure-the overall sulfate content and 4- to 6-sulfate ratio. In general, the CS chains of the corneal CSPGs have low to moderate levels (15-64%) of sulfated disaccharides and 0-30% DS content. Structural analysis indicated that the DS disaccharide units in the CS chains are segregated as large blocks. We have also assessed the suitability of the corneal CSPGs as an alternative to placental CSPG or the widely used bovine tracheal chondroitin sulfate A (CSA) for studying the structural interactions involved in the adherence of Plasmodium falciparum-infected red blood cells (IRBCs) to chondroitin 4-sulfate. The data demonstrate that the corneal CSPGs efficiently bind IRBCs, and that the binding strength is either comparable or significantly higher than the placental CSPG. In contrast, the IRBC binding strength of bovine tracheal CSA is markedly lower than the human placental and bovine corneal CSPGs. Thus, our data demonstrate that the bovine corneal CSPG but not tracheal CSA is suitable for studying structural interactions involved in IRBC-C4S binding.
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Affiliation(s)
- Rajeshwara N Achur
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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Muthusamy A, Achur RN, Valiyaveettil M, Gowda DC. Plasmodium falciparum: adherence of the parasite-infected erythrocytes to chondroitin sulfate proteoglycans bearing structurally distinct chondroitin sulfate chains. Exp Parasitol 2004; 107:183-8. [PMID: 15363944 DOI: 10.1016/j.exppara.2004.05.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2003] [Revised: 05/13/2004] [Accepted: 05/19/2004] [Indexed: 11/21/2022]
Abstract
Infection with Plasmodium falciparum during pregnancy leads to the selective adherence of infected red blood cells (IRBCs) in the placenta causing placental malaria. The IRBC adherence is mediated through the chondroitin 4-sulfate (C4S) chains of unusually low-sulfated chondroitin sulfate proteoglycans (CSPGs) in the placenta. To study the structural interactions involved in C4S-IRBC adherence, various investigators have used CSPGs from different sources. Since the structural characteristics of the polysaccharide chains in CSPGs from various sources differ substantially, the CSPGs are likely to differentially bind IRBCs. In this study, the CSPG purified from bovine trachea, a CSPG form of human recombinant thrombomodulin (TM-CSPG), two CSPG fractions from bovine cornea, and the CSPGs of human placenta, the natural receptor, were studied in parallel for their IRBC binding characteristics. The TM-CSPG and corneal CSPG fractions could bind IRBCs at significantly higher density compared to the placental CSPGs. However, the avidity of IRBC binding by TM-CSPG was considerably low compared to placental CSPGs. The corneal CSPGs have substantially higher binding strengths. The bovine tracheal CSPG bound IRBCs at much lower density and exhibited significantly lower avidity than the placental CSPGs. These data demonstrated that the bovine tracheal CSPG and TM-CSPG are not ideal for studying the fine structural interactions involved in the IRBC adherence to the placental C4S, whereas the bovine corneal CSPGs are better alternatives to the placental CSPGs for determining these interactions.
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Affiliation(s)
- Arivalagan Muthusamy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey 17033, USA
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Götting C, Müller S, Schöttler M, Schön S, Prante C, Brinkmann T, Kuhn J, Kleesiek K. Analysis of the DXD motifs in human xylosyltransferase I required for enzyme activity. J Biol Chem 2004; 279:42566-73. [PMID: 15294915 DOI: 10.1074/jbc.m401340200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human xylosyltransferase I (XT-I) is the initial enzyme involved in the biosynthesis of the glycosaminoglycan linker region in proteoglycans. Here, we tested the importance of the DXD motifs at positions 314-316 and 745-747 for enzyme activity and the nucleotide binding capacity of human XT-I. Mutations of the 314DED316 motif did not have any effect on enzyme activity, whereas alterations of the 745DWD747 motif resulted in reduced XT-I activity. Loss of function was observed after exchange of the highly conserved aspartic acid at position 745 with glycine. However, mutation of Asp745 to glutamic acid retained full enzyme activity, indicating the importance of an acidic amino acid at this position. Reduced substrate affinity was observed for mutants D747G (Km=6.9 microm) and D747E (Km=4.4 microm) in comparison with the wild-type enzyme (Km=0.9 microm). Changing the central tryptophan to a neutral, basic, or acidic amino acid resulted in a 6-fold lower Vmax, with Km values comparable with those of the wild-type enzyme. Despite the major effect of the DWD motif on XT-I activity, nucleotide binding was not abolished in the D745G and D747G mutants, as revealed by UDP-bead binding assays. Ki values for inhibition by UDP were determined to be 1.9-24.6 microm for the XT-I mutants. The properties of binding of XT-I to heparin-beads, the Ki constants for noncompetitive inhibition by heparin, and the activation by protamine were not altered by the generated mutations.
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Affiliation(s)
- Christian Götting
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Georgstrasse 11, 32545 Bad Oeynhausen, Germany.
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Muthusamy A, Achur RN, Bhavanandan VP, Fouda GG, Taylor DW, Gowda DC. Plasmodium falciparum-infected erythrocytes adhere both in the intervillous space and on the villous surface of human placenta by binding to the low-sulfated chondroitin sulfate proteoglycan receptor. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:2013-25. [PMID: 15161637 PMCID: PMC1615783 DOI: 10.1016/s0002-9440(10)63761-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In pregnant women infected with Plasmodium falciparum, the parasite-infected red blood cells (IRBCs) sequester in the placenta through chondroitin 4-sulfate (C4S)-mediated adherence. The pattern of IRBC adherence in P. falciparum-infected placenta has been controversial. Moreover, the identity of the chondroitin sulfate proteoglycan (CSPG) receptor, that mediates IRBC adherence, and its location in the placenta have not been established. This study, using immunohistochemical techniques, clearly shows, for the first time, that the low-sulfated CSPGs of the placenta are localized predominantly in the intervillous space. Ex vivo IRBC adherence analyses demonstrate that the IRBCs are adhered to the CSPG receptors in the placenta in a C4S-dependent manner. This IRBC binding pattern was similar to that observed in P. falciparum-infected placentas. These data and the results of dual-fluorescence staining of the endogenous RBCs and syncytiotrophoblasts, and co-localization of CSPG and IRBC adherence unequivocally establish that the low-sulfated CSPGs are the major natural receptors for IRBC adherence in the placenta. Further, it was found that IRBCs adhere mainly in the intervillous space and also at significant levels to the syncytiotrophoblasts. Finally, the ex vivo IRBC adherence method described herein provides a reliable procedure for future studies for the assessment of the efficacy of C4S inhibitors and adhesion inhibitory antibodies.
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Affiliation(s)
- Arivalagan Muthusamy
- Department of Biochemistry and Molecular Biology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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Abstract
Glycosylation is a common post-translational modification to cell surface and extracellular matrix (ECM) proteins as well as to lipids. As a result, cells carry a dense coat of carbohydrates on their surfaces that mediates a wide variety of cell-cell and cell-matrix interactions that are crucial to development and function. Because of the historical difficulties with the analysis of complex carbohydrate structures, a detailed understanding of their roles in biology has been slow to develop. Just as mass spectrometry has proven to be the core technology behind proteomics, it stands to play a similar role in the study of functional implications of carbohydrate expression, known as glycomics. This review summarizes the state of knowledge for the mass spectrometric analysis of oligosaccharides with regard to neutral, sialylated, and sulfated compound classes. Mass spectrometric techniques for the ionization and fragmentation of oligosaccharides are discussed so as to give the reader the background to make informed decisions to solve structure-activity relations in glycomics.
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Affiliation(s)
- Joseph Zaia
- Department of Biochemistry, Boston University School of Medicine, 715 Albany St., R-806, Boston, Massachusetts 02118, USA.
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