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Lünemann JD, von Gunten S, Neumann H. Targeting sialylation to treat central nervous system diseases. Trends Pharmacol Sci 2021; 42:998-1008. [PMID: 34607695 DOI: 10.1016/j.tips.2021.09.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 02/03/2023]
Abstract
Sialic acid-binding immunoglobulin-type lectins (SIGLECs) are membrane receptors that are preferentially expressed on immune cells and recognize sialylated proteins, lipids, and RNA. Sialic acids and signaling through SIGLECs are increasingly recognized for their essential roles in immune system homeostasis as well as nervous system development, plasticity, and repair. Dysregulated sialylation and SIGLEC dysfunctions contribute to several chronic diseases of the central nervous system (CNS) in which current therapeutic options are very limited. While only a few therapies targeting SIGLECs are currently being tested in clinical trials, the area emerged as one of the most dynamic and active fields in glycobiology and drug development. This review highlights recent insights into sialic acid and SIGLEC function in CNS pathologies and illustrates opportunities and challenges for the development of sialic acid-based and SIGLEC-targeted therapies for neurological diseases.
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Affiliation(s)
- Jan D Lünemann
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster, Münster, Germany.
| | | | - Harald Neumann
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
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2
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Saini V, Kaur T, Kalotra S, Kaur G. The neuroplasticity marker PSA-NCAM: Insights into new therapeutic avenues for promoting neuroregeneration. Pharmacol Res 2020; 160:105186. [DOI: 10.1016/j.phrs.2020.105186] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 08/25/2020] [Accepted: 08/30/2020] [Indexed: 02/06/2023]
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3
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Wielgat P, Rogowski K, Niemirowicz-Laskowska K, Car H. Sialic Acid-Siglec Axis as Molecular Checkpoints Targeting of Immune System: Smart Players in Pathology and Conventional Therapy. Int J Mol Sci 2020; 21:ijms21124361. [PMID: 32575400 PMCID: PMC7352527 DOI: 10.3390/ijms21124361] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/17/2020] [Accepted: 06/17/2020] [Indexed: 12/11/2022] Open
Abstract
The sialic acid-based molecular mimicry in pathogens and malignant cells is a regulatory mechanism that leads to cross-reactivity with host antigens resulting in suppression and tolerance in the immune system. The interplay between sialoglycans and immunoregulatory Siglec receptors promotes foreign antigens hiding and immunosurveillance impairment. Therefore, molecular targeting of immune checkpoints, including sialic acid-Siglec axis, is a promising new field of inflammatory disorders and cancer therapy. However, the conventional drugs used in regular management can interfere with glycome machinery and exert a divergent effect on immune controlling systems. Here, we focus on the known effects of standard therapies on the sialoglycan-Siglec checkpoint and their importance in diagnosis, prediction, and clinical outcomes.
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Affiliation(s)
- Przemyslaw Wielgat
- Department of Clinical Pharmacology, Medical University of Bialystok, Waszyngtona 15A, 15-274 Bialystok, Poland;
- Correspondence: ; Tel.: +48-85-7450-647
| | - Karol Rogowski
- Department of Experimental Pharmacology, Medical University of Bialystok, Szpitalna 37, 15-295 Bialystok, Poland; (K.R.); (K.N.-L.)
| | - Katarzyna Niemirowicz-Laskowska
- Department of Experimental Pharmacology, Medical University of Bialystok, Szpitalna 37, 15-295 Bialystok, Poland; (K.R.); (K.N.-L.)
| | - Halina Car
- Department of Clinical Pharmacology, Medical University of Bialystok, Waszyngtona 15A, 15-274 Bialystok, Poland;
- Department of Experimental Pharmacology, Medical University of Bialystok, Szpitalna 37, 15-295 Bialystok, Poland; (K.R.); (K.N.-L.)
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Janesch B, Baumann L, Mark A, Thompson N, Rahmani S, Sim L, Withers SG, Wakarchuk WW. Directed evolution of bacterial polysialyltransferases. Glycobiology 2020; 29:588-598. [PMID: 30976781 DOI: 10.1093/glycob/cwz021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/15/2019] [Accepted: 03/18/2019] [Indexed: 01/30/2023] Open
Abstract
Polysialyltransferases (polySTs) are glycosyltransferases that synthesize polymers of sialic acid found in vertebrates and some bacterial pathogens. Bacterial polySTs have utility in the modification of therapeutic proteins to improve serum half-life, and the potential for tissue engineering. PolySTs are membrane-associated proteins and as recombinant proteins suffer from inherently low solubility, low expression levels and poor thermal stability. To improve their physicochemical and biochemical properties, we applied a directed evolution approach using a FACS-based ultrahigh-throughput assay as a simple, robust and reliable screening method. We were able to enrich a large mutant library and, in combination with plate-based high-throughput secondary screening, we discovered mutants with increased enzymatic activity and improved stability compared to the wildtype enzyme. This work presents a powerful strategy for the screening of directed evolution libraries of bacterial polySTs to identify better catalysts for in vitro polysialylation of therapeutics.
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Affiliation(s)
- Bettina Janesch
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Lars Baumann
- Departments of Chemistry and Biochemistry, and Michael Smith Laboratory, University of British Columbia, Vancouver, BC, Canada
| | - Alison Mark
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Nicole Thompson
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Sadia Rahmani
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Lyann Sim
- Departments of Chemistry and Biochemistry, and Michael Smith Laboratory, University of British Columbia, Vancouver, BC, Canada
| | - Stephen G Withers
- Departments of Chemistry and Biochemistry, and Michael Smith Laboratory, University of British Columbia, Vancouver, BC, Canada
| | - Warren W Wakarchuk
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
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Sapoń K, Janas T, Janas T. Biophysical Characterization of Polysialic Acid—Membrane Nanosystems. SERIES IN BIOENGINEERING 2019. [DOI: 10.1007/978-981-13-0989-2_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abstract
Simple and complex carbohydrates (glycans) have long been known to play major metabolic, structural and physical roles in biological systems. Targeted microbial binding to host glycans has also been studied for decades. But such biological roles can only explain some of the remarkable complexity and organismal diversity of glycans in nature. Reviewing the subject about two decades ago, one could find very few clear-cut instances of glycan-recognition-specific biological roles of glycans that were of intrinsic value to the organism expressing them. In striking contrast there is now a profusion of examples, such that this updated review cannot be comprehensive. Instead, a historical overview is presented, broad principles outlined and a few examples cited, representing diverse types of roles, mediated by various glycan classes, in different evolutionary lineages. What remains unchanged is the fact that while all theories regarding biological roles of glycans are supported by compelling evidence, exceptions to each can be found. In retrospect, this is not surprising. Complex and diverse glycans appear to be ubiquitous to all cells in nature, and essential to all life forms. Thus, >3 billion years of evolution consistently generated organisms that use these molecules for many key biological roles, even while sometimes coopting them for minor functions. In this respect, glycans are no different from other major macromolecular building blocks of life (nucleic acids, proteins and lipids), simply more rapidly evolving and complex. It is time for the diverse functional roles of glycans to be fully incorporated into the mainstream of biological sciences.
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Affiliation(s)
- Ajit Varki
- Departments of Medicine and Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California at San Diego, La Jolla, CA 92093-0687, USA
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Stepp MA, Tadvalkar G, Hakh R, Pal-Ghosh S. Corneal epithelial cells function as surrogate Schwann cells for their sensory nerves. Glia 2016; 65:851-863. [PMID: 27878997 DOI: 10.1002/glia.23102] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 10/30/2016] [Accepted: 11/02/2016] [Indexed: 12/13/2022]
Abstract
The eye is innervated by neurons derived from both the central nervous system and peripheral nervous system (PNS). While much is known about retinal neurobiology and phototransduction, less attention has been paid to the innervation of the eye by the PNS and the roles it plays in maintaining a functioning visual system. The ophthalmic branch of the trigeminal ganglion contains somas of neurons that innervate the cornea. These nerves provide sensory functions for the cornea and are referred to as intraepithelial corneal nerves (ICNs) consisting of subbasal nerves and their associated intraepithelial nerve terminals. ICNs project for several millimeters within the corneal epithelium without Schwann cell support. Here, we present evidence for the hypothesis that corneal epithelial cells function as glial cells to support the ICNs. Much of the data supporting this hypothesis is derived from studies of corneal development and the reinnervation of the ICNs in the rodent and rabbit cornea after superficial wounds. Corneal epithelial cells activate in response to injury via mechanisms similar to those induced in Schwann cells during Wallerian Degeneration. Corneal epithelial cells phagocytize distal axon fragments within hours of ICN crush wounds. During aging, the proteins, lipids, and mitochondria within the ICNs become damaged in a process exacerbated by UV light. We propose that ICNs shed their aged and damaged termini and continuously elongate to maintain their density. Available evidence points to new unexpected roles for corneal epithelial cells functioning as surrogate Schwann cells for the ICNs during homeostasis and in response to injury. GLIA 2017;65:851-863.
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Affiliation(s)
- Mary Ann Stepp
- Department of Anatomy and Regenerative Biology, George Washington University Medical School, Washington, DC
| | - Gauri Tadvalkar
- Department of Anatomy and Regenerative Biology, George Washington University Medical School, Washington, DC
| | - Raymond Hakh
- Department of Anatomy and Regenerative Biology, George Washington University Medical School, Washington, DC
| | - Sonali Pal-Ghosh
- Department of Anatomy and Regenerative Biology, George Washington University Medical School, Washington, DC
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Mehrabian M, Hildebrandt H, Schmitt-Ulms G. NCAM1 Polysialylation: The Prion Protein's Elusive Reason for Being? ASN Neuro 2016; 8:8/6/1759091416679074. [PMID: 27879349 PMCID: PMC5122176 DOI: 10.1177/1759091416679074] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 09/08/2016] [Accepted: 10/02/2016] [Indexed: 01/06/2023] Open
Abstract
Much confusion surrounds the physiological function of the cellular prion protein (PrPC). It is, however, anticipated that knowledge of its function will shed light on its contribution to neurodegenerative diseases and suggest ways to interfere with the cellular toxicity central to them. Consequently, efforts to elucidate its function have been all but exhaustive. Building on earlier work that uncovered the evolutionary descent of the prion founder gene from an ancestral ZIP zinc transporter, we recently investigated a possible role of PrPC in a morphogenetic program referred to as epithelial-to-mesenchymal transition (EMT). By capitalizing on PrPC knockout cell clones in a mammalian cell model of EMT and using a comparative proteomics discovery strategy, neural cell adhesion molecule-1 emerged as a protein whose upregulation during EMT was perturbed in PrPC knockout cells. Follow-up work led us to observe that PrPC regulates the polysialylation of the neural cell adhesion molecule NCAM1 in cells undergoing morphogenetic reprogramming. In addition to governing cellular migration, polysialylation modulates several other cellular plasticity programs PrPC has been phenotypically linked to. These include neurogenesis in the subventricular zone, controlled mossy fiber sprouting and trimming in the hippocampal formation, hematopoietic stem cell renewal, myelin repair and maintenance, integrity of the circadian rhythm, and glutamatergic signaling. This review revisits this body of literature and attempts to present it in light of this novel contextual framework. When approached in this manner, a coherent model of PrPC acting as a regulator of polysialylation during specific cell and tissue morphogenesis events comes into focus.
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Affiliation(s)
- Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Herbert Hildebrandt
- Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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Saini V, Lutz D, Kataria H, Kaur G, Schachner M, Loers G. The polysialic acid mimetics 5-nonyloxytryptamine and vinorelbine facilitate nervous system repair. Sci Rep 2016; 6:26927. [PMID: 27324620 PMCID: PMC4914991 DOI: 10.1038/srep26927] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 04/07/2016] [Indexed: 02/05/2023] Open
Abstract
Polysialic acid (PSA) is a large negatively charged glycan mainly attached to the neural cell adhesion molecule (NCAM). Several studies have shown that it is important for correct formation of brain circuitries during development and for synaptic plasticity, learning and memory in the adult. PSA also plays a major role in nervous system regeneration following injury. As a next step for clinical translation of PSA based therapeutics, we have previously identified the small organic compounds 5-nonyloxytryptamine and vinorelbine as PSA mimetics. Activity of 5-nonyloxytryptamine and vinorelbine had been confirmed in assays with neural cells from the central and peripheral nervous system in vitro and shown to be independent of their function as serotonin receptor 5-HT1B/1D agonist or cytostatic drug, respectively. As we show here in an in vivo paradigm for spinal cord injury in mice, 5-nonyloxytryptamine and vinorelbine enhance regain of motor functions, axonal regrowth, motor neuron survival and remyelination. These data indicate that 5-nonyloxytryptamine and vinorelbine may be re-tasked from their current usage as a 5-HT1B/1D agonist or cytostatic drug to act as mimetics for PSA to stimulate regeneration after injury in the mammalian nervous system.
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Affiliation(s)
- Vedangana Saini
- Department of Biotechnology, Guru Nanak Dev University, GT Road, 143005 Amritsar, India
- Center for Molecular Neurobiology, University Hospital Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
| | - David Lutz
- Center for Molecular Neurobiology, University Hospital Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
| | - Hardeep Kataria
- Center for Molecular Neurobiology, University Hospital Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
| | - Gurcharan Kaur
- Department of Biotechnology, Guru Nanak Dev University, GT Road, 143005 Amritsar, India
| | - Melitta Schachner
- Keck Center for Collaborative Neurosciences, Rutgers University, Piscataway, NJ 08854, USA
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, People’s Republic of China
| | - Gabriele Loers
- Center for Molecular Neurobiology, University Hospital Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
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Loers G, Saini V, Mishra B, Gul S, Chaudhury S, Wallqvist A, Kaur G, Schachner M. Vinorelbine and epirubicin share common features with polysialic acid and modulate neuronal and glial functions. J Neurochem 2016; 136:48-62. [PMID: 26443186 PMCID: PMC4904230 DOI: 10.1111/jnc.13383] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/21/2015] [Accepted: 10/02/2015] [Indexed: 02/05/2023]
Abstract
Polysialic acid (PSA), a large, linear glycan composed of 8 to over 100 α2,8-linked sialic acid residues, modulates development of the nervous system by enhancing cell migration, axon pathfinding, and synaptic targeting and by regulating differentiation of progenitor cells. PSA also functions in developing and adult immune systems and is a signature of many cancers. In this study we identified vinorelbine, a semi-synthetic third generation vinca alkaloid, and epirubicin, an anthracycline and 4'-epimer of doxorubicin, as PSA mimetics. Similar to PSA, vinorelbine and epirubicin bind to the PSA-specific monoclonal antibody 735 and compete with the bacterial analog of PSA, colominic acid in binding to monoclonal antibody 735. Vinorelbine and epirubicin stimulate neurite outgrowth of cerebellar neurons via the neural cell adhesion molecule, via myristoylated alanine-rich C kinase substrate, and via fibroblast growth factor receptor, signaling through Erk pathways. Furthermore, the two compounds enhance process formation of Schwann cells and migration of cerebellar neurons in culture, and reduce migration of astrocytes after injury. These novel results show that the structure and function of PSA can be mimicked by the small organic compounds vinorelbine and epirubicin, thus raising the possibility to re-target drugs used in treatment of cancers to nervous system repair. Vinorelbine and epirubicin, identified as PSA mimetics, enhance, like PSA, neuronal migration, neuritogenesis, and formation of Schwann cell processes, and reduce astrocytic migration. Ablating NCAM, inhibiting fibroblast growth factor (FGFR) receptor, or adding the effector domain of myristoylated alanine-rich C kinase substrate (MARCKS) minimize the vinorelbine and epirubicin effects, indicating that they are true PSA mimetics triggering PSA-mediated functions.
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Affiliation(s)
- Gabriele Loers
- Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
| | - Vedangana Saini
- Department of Biotechnology, Guru Nanak Dev University, GT Road, 143005 Amritsar, India
| | - Bibhudatta Mishra
- Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
| | - Sheraz Gul
- Fraunhofer Institute for Molecular Biology and Applied Ecology ScreeningPort (Fraunhofer-IME SP), Schnackenburgalle114, D-22525 Hamburg, Germany
| | - Sidhartha Chaudhury
- DoD Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, US Army Medical Research and Materiel Command, Fort Detrick, MD 21702 (USA)
| | - Anders Wallqvist
- DoD Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, US Army Medical Research and Materiel Command, Fort Detrick, MD 21702 (USA)
| | - Gurcharan Kaur
- Department of Biotechnology, Guru Nanak Dev University, GT Road, 143005 Amritsar, India
| | - Melitta Schachner
- Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
- Keck Center for Collaborative Neuroscience and Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854, USA
- Center for Neuroscience, Shantou University Medical College, 22 Xin Ling Road, Shantou, Guangdong 515041, China
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Mehrabian M, Brethour D, Wang H, Xi Z, Rogaeva E, Schmitt-Ulms G. The Prion Protein Controls Polysialylation of Neural Cell Adhesion Molecule 1 during Cellular Morphogenesis. PLoS One 2015; 10:e0133741. [PMID: 26288071 PMCID: PMC4546001 DOI: 10.1371/journal.pone.0133741] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 06/19/2015] [Indexed: 01/06/2023] Open
Abstract
Despite its multi-faceted role in neurodegenerative diseases, the physiological function of the prion protein (PrP) has remained elusive. On the basis of its evolutionary relationship to ZIP metal ion transporters, we considered that PrP may contribute to the morphogenetic reprogramming of cells underlying epithelial-to-mesenchymal transitions (EMT). Consistent with this hypothesis, PrP transcription increased more than tenfold during EMT, and stable PrP-deficient cells failed to complete EMT in a mammalian cell model. A global comparative proteomics analysis identified the neural cell adhesion molecule 1 (NCAM1) as a candidate mediator of this impairment, which led to the observation that PrP-deficient cells fail to undergo NCAM1 polysialylation during EMT. Surprisingly, this defect was caused by a perturbed transcription of the polysialyltransferase ST8SIA2 gene. Proteomics data pointed toward β-catenin as a transcriptional regulator affected in PrP-deficient cells. Indeed, pharmacological blockade or siRNA-based knockdown of β-catenin mimicked PrP-deficiency in regards to NCAM1 polysialylation. Our data established the existence of a PrP-ST8SIA2-NCAM signaling loop, merged two mature fields of investigation and offer a simple model for explaining phenotypes linked to PrP.
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Affiliation(s)
- Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Dylan Brethour
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Hansen Wang
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Zhengrui Xi
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Ekaterina Rogaeva
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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12
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Koulaxouzidis G, Reutter W, Hildebrandt H, Stark GB, Witzel C. In vivo stimulation of early peripheral axon regeneration by N-propionylmannosamine in the presence of polysialyltransferase ST8SIA2. J Neural Transm (Vienna) 2015; 122:1211-9. [PMID: 25850639 DOI: 10.1007/s00702-015-1397-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Accepted: 03/25/2015] [Indexed: 01/19/2023]
Abstract
The key enzyme of sialic acid (Sia) biosynthesis is the bifunctional UDP-N-acetylglucosamine 2-epimerase/ManNAc kinase (GNE/MNK). It metabolizes the physiological precursor ManNAc and N-acyl modified analogues such as N-propionylmannosamine (ManNProp) to the respective modified sialic acid. Polysialic acid (polySia) is a crucial compound for several functions in the nervous system and is synthesized by the polysialyltransferases ST8SIA2 and ST8SIA4. PolySia can be modified in vitro and in vivo by metabolic glycoengineering of the N-acyl side chain of Sia. In vitro studies show that the application of ManNProp increases neurite outgrowth and accelerates the re-establishment of functional synapses. In this study, we investigate in vivo how ManNProp application might benefit peripheral nerve regeneration. In mice expressing axonal fluorescent proteins (thy-1-YFP), we transected the sciatic nerve and then replaced part of it with a sciatic nerve graft from non-expressing mice (wild-type mice or St8sia2(-/-) mice). Analyses conducted 5 days after grafting showed that systemic application of ManNProp (200 mg/kg, twice a day, i.p.), but not of physiological ManNAc (1 g/kg, twice a day, i.p.), significantly increased the extent of axonal elongation, the number of arborizing axons and the number of branches per regenerating axon within the grafts from wild-type mice, but not in those from St8sia2(-/-) mice. The results demonstrate that the application of ManNProp has beneficial effects on early peripheral nerve regeneration and indicate that the stimulation of axon growth depends on ST8SIA2 activity in the nerve graft.
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Affiliation(s)
- Georgios Koulaxouzidis
- Klinik für Plastische und Handchirurgie, Universitätsklinikum Freiburg, Freiburg, Germany,
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13
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Pan HC, Shen YQ, Loers G, Jakovcevski I, Schachner M. Tegaserod, a small compound mimetic of polysialic acid, promotes functional recovery after spinal cord injury in mice. Neuroscience 2014; 277:356-66. [PMID: 25014876 DOI: 10.1016/j.neuroscience.2014.06.069] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 06/08/2014] [Accepted: 06/26/2014] [Indexed: 02/05/2023]
Abstract
In a previous study, we have shown that the small organic compound tegaserod, a drug approved for clinical application in an unrelated condition, is a mimic of the regeneration-beneficial glycan polysialic acid (PSA) in a mouse model of femoral nerve injury. Several independent observations have shown positive effects of PSA and its mimetic peptides in different paradigms of injury of the central and peripheral mammalian nervous systems. Since small organic compounds generally have advantages over metabolically rapidly degraded glycans and the proteolytically vulnerable mimetic peptides, a screen for a small PSA mimetic compound was successfully carried out, and the identified molecule proved to be beneficial in neurite outgrowth in vitro, independent of its originally described function as a 5-HT4 receptor agonist. In the present study, a mouse spinal cord compression device was used to elicit severe compression injury. We show that tegaserod promotes hindlimb motor function at 6 weeks after spinal cord injury compared to the control group receiving vehicle only. Immunohistology of the spinal cord rostral and caudal to the lesion site showed increased numbers of neurons, and a reduced area and intensity of glial fibrillary acidic protein immunoreactivity. Quantification of regrowth/sprouting of axons immunoreactive for tyrosine hydroxylase and serotonin showed increased axonal density rostral and caudal to the injury site in the ventral horns of mice treated with tegaserod. The combined observations suggest that tegaserod has the potential for treatment of spinal cord injuries in higher vertebrates.
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Affiliation(s)
- H-C Pan
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Y-Q Shen
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, China; Jiangnan University Medical School, Wuxi, Jiangsu 214122, China
| | - G Loers
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, University of Hamburg, Hamburg D-20246, Germany
| | - I Jakovcevski
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, University of Hamburg, Hamburg D-20246, Germany
| | - M Schachner
- Center for Neuroscience, Shantou University Medical College, Shantou, Guangdong 515041, China.
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Tegaserod mimics the neurostimulatory glycan polysialic acid and promotes nervous system repair. Neuropharmacology 2013; 79:456-66. [PMID: 24067923 PMCID: PMC4618794 DOI: 10.1016/j.neuropharm.2013.09.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 08/30/2013] [Accepted: 09/11/2013] [Indexed: 11/21/2022]
Abstract
Glycans attached to the cell surface via proteins or lipids or exposed in the extracellular matrix affect many cellular processes, including neuritogenesis, cell survival and migration, as well as synaptic activity and plasticity. These functions make glycans attractive molecules for stimulating repair of the injured nervous system. Yet, glycans are often difficult to synthesize or isolate and have the disadvantage to be unstable in a complex tissue environment. To circumvent these issues, we have screened a library of small organic compounds to search for structural and functional mimetics of the neurostimulatory glycan polysialic acid (PSA) and identified the 5-HT4 receptor agonist tegaserod as a PSA mimetic. The PSA mimicking activity of tegaserod was shown in cultures of central and peripheral nervous system cells of the mouse and found to be independent of its described function as a serotonin (5-HT4) receptor agonist. In an in vivo model for peripheral nerve regeneration, mice receiving tegaserod at the site of injury showed enhanced recovery compared to control mice receiving vehicle control as evidenced by functional measurements and histology. These data indicate that tegaserod could be repurposed for treatment of nervous system injuries and underscores the potential of using small molecules as mimetics of neurostimulatory glycans.
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