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Borroto-Escuela D, Serrano-Castro P, Sánchez-Pérez JA, Barbancho-Fernández MA, Fuxe K, Narváez M. Enhanced neuronal survival and BDNF elevation via long-term co-activation of galanin 2 (GALR2) and neuropeptide Y1 receptors (NPY1R): potential therapeutic targets for major depressive disorder. Expert Opin Ther Targets 2024; 28:295-308. [PMID: 38622072 DOI: 10.1080/14728222.2024.2342517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 04/05/2024] [Indexed: 04/17/2024]
Abstract
BACKGROUND Major Depressive Disorder (MDD) is a prevalent and debilitating condition, necessitating novel therapeutic strategies due to the limited efficacy and adverse effects of current treatments. We explored how galanin receptor 2 (GALR2) and Neuropeptide Y1 Receptor (NPYY1R) agonists, working together, can boost brain cell growth and increase antidepressant-like effects in rats. This suggests new ways to treat Major Depressive Disorder (MDD). RESEARCH DESIGN AND METHODS In a controlled laboratory setting, adult naive Sprague-Dawley rats were administered directly into the brain's ventricles, a method known as intracerebroventricular (ICV) administration, with GALR2 agonist (M1145), NPYY1R agonist, both, or in combination with a GALR2 antagonist (M871). Main outcome measures included long-term neuronal survival, differentiation, and behavioral. RESULTS Co-administration of M1145 and NPYY1R agonist significantly enhanced neuronal survival and maturation in the ventral dentate gyrus, with a notable increase in Brain-Derived Neurotrophic Factor (BDNF) expression. This neurogenic effect was associated with an antidepressant-like effect, an outcome partially reversed by M871. CONCLUSIONS GALR2 and NPYY1R agonists jointly promote hippocampal neurogenesis and exert antidepressant-like effects in rats without adverse outcomes, highlighting their therapeutic potential for MDD. The study's reliance on an animal model and intracerebroventricular delivery warrants further clinical exploration to confirm these promising results.
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MESH Headings
- Animals
- Male
- Rats
- Antidepressive Agents/pharmacology
- Antidepressive Agents/administration & dosage
- Brain-Derived Neurotrophic Factor/metabolism
- Cell Survival/drug effects
- Depressive Disorder, Major/drug therapy
- Depressive Disorder, Major/physiopathology
- Disease Models, Animal
- Neurons/drug effects
- Neurons/metabolism
- Peptides
- Rats, Sprague-Dawley
- Receptor, Galanin, Type 2/metabolism
- Receptors, G-Protein-Coupled
- Receptors, Neuropeptide
- Receptors, Neuropeptide Y/metabolism
- Receptors, Neuropeptide Y/antagonists & inhibitors
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Affiliation(s)
- Dasiel Borroto-Escuela
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Receptomics and Brain Disorders Lab, Edificio Lopez-Peñalver, Instituto de Investigación Biomédica de Málaga, Facultad de Medicina, Universidad de Málaga, Málaga, Spain
| | - Pedro Serrano-Castro
- Instituto de Investigación Biomédica de Málaga, NeuronLab, Facultad de Medicina, Universidad de Málaga, Málaga, Spain
- Instituto de Investigación Biomédica de Málaga, Unit of Neurology, Hospital Regional Universitario de Málaga, Málaga, Spain
- Vithas Málaga, Vithas Málaga, Grupo Hospitalario Vithas, Málaga, Spain
| | - Jose Andrés Sánchez-Pérez
- Instituto de Investigación Biomédica de Málaga, NeuronLab, Facultad de Medicina, Universidad de Málaga, Málaga, Spain
- Instituto de Investigación Biomédica de Málaga, Unit of Psychiatry, Hospital Universitario Virgen de la Victoria, Málaga, Spain
| | | | - Kjell Fuxe
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Manuel Narváez
- Instituto de Investigación Biomédica de Málaga, NeuronLab, Facultad de Medicina, Universidad de Málaga, Málaga, Spain
- Instituto de Investigación Biomédica de Málaga, Unit of Neurology, Hospital Regional Universitario de Málaga, Málaga, Spain
- Vithas Málaga, Vithas Málaga, Grupo Hospitalario Vithas, Málaga, Spain
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Galanin and Neuropeptide Y Interaction Enhances Proliferation of Granule Precursor Cells and Expression of Neuroprotective Factors in the Rat Hippocampus with Consequent Augmented Spatial Memory. Biomedicines 2022; 10:biomedicines10061297. [PMID: 35740319 PMCID: PMC9219743 DOI: 10.3390/biomedicines10061297] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 05/27/2022] [Accepted: 05/28/2022] [Indexed: 02/04/2023] Open
Abstract
Dysregulation of hippocampal neurogenesis is linked to several neurodegenereative diseases, where boosting hippocampal neurogenesis in these patients emerges as a potential therapeutic approach. Accumulating evidence for a neuropeptide Y (NPY) and galanin (GAL) interaction was shown in various limbic system regions at molecular-, cellular-, and behavioral-specific levels. The purpose of the current work was to evaluate the role of the NPY and GAL interaction in the neurogenic actions on the dorsal hippocampus. We studied the Y1R agonist and GAL effects on: hippocampal cell proliferation through the proliferating cell nuclear antigen (PCNA), the expression of neuroprotective and anti-apoptotic factors, and the survival of neurons and neurite outgrowth on hippocampal neuronal cells. The functional outcome was evaluated in the object-in-place task. We demonstrated that the Y1R agonist and GAL promote cell proliferation and the induction of neuroprotective factors. These effects were mediated by the interaction of NPYY1 (Y1R) and GAL2 (GALR2) receptors, which mediate the increased survival and neurites’ outgrowth observed on neuronal hippocampal cells. These cellular effects are linked to the improved spatial-memory effects after the Y1R agonist and GAL co-injection at 24 h in the object-in-place task. Our results suggest the development of heterobivalent agonist pharmacophores, targeting Y1R–GALR2 heterocomplexes, therefore acting on the neuronal precursor cells of the DG in the dorsal hippocampus for the novel therapy of neurodegenerative cognitive-affecting diseases.
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Habuchi O. Functions of chondroitin/dermatan sulfate containing GalNAc4,6-disulfate. Glycobiology 2022; 32:664-678. [PMID: 35552694 DOI: 10.1093/glycob/cwac030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/05/2022] [Accepted: 05/05/2022] [Indexed: 11/13/2022] Open
Abstract
Chondroitin sulfate (CS) and dermatan sulfate (DS) containing GalNAc4,6-disulfate (GalNAc4S6S) were initially discovered in marine animals. Following the discovery, these glycosaminoglycans have been found in various animals including human. In the biosynthesis of CS/DS containing GalNAc4S6S, three groups of sulfotransferases are involved; chondroitin 4-sulfotransferases (C4STs), dermatan 4-sulfotransferase-1 (D4ST-1) and GalNAc 4-sulfate 6-O-sulfotransferase (GalNAc4S-6ST). GalNAc4S-6ST and its products have been shown to play important roles in the abnormal pathological conditions such as central nervous system injury, cancer development, abnormal tissue fibrosis, development of osteoporosis, and infection with viruses or nematodes. CS/DS containing GalNAc4S6S has been shown to increase with the functional differentiation of mast cells, macrophages and neutrophils. Genetic approaches using knockout or knockdown of GalNAc4S-6ST, blocking of the epitopes containing GalNAc4S6S by specific antibodies and chemical technology that enabled the synthesis of oligosaccharides with defined sulfation patterns have been applied successfully to these investigations. These studies contributed significantly to the basic understanding of the functional roles of CS/DS containing GalNAc4S6S in various abnormal conditions, and appear to provide promising clues to the development of possible measures to treat them.
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Affiliation(s)
- Osami Habuchi
- Multidisciplinary Pain Center, Aichi Medical University, Nagakute, Aichi 480-1195, Japan.,Department of Chemistry, Aichi University of Education, Igayacho, Kariya, Aichi 448-8542, Japan
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Li P, Wen S, Sun K, Zhao Y, Chen Y. Structure and Bioactivity Screening of a Low Molecular Weight Ulvan from the Green Alga Ulothrix flacca. Mar Drugs 2018; 16:md16080281. [PMID: 30111709 PMCID: PMC6117715 DOI: 10.3390/md16080281] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/03/2018] [Accepted: 08/09/2018] [Indexed: 12/31/2022] Open
Abstract
A water-soluble low molecular–weight polysaccharide named UP2-1 was isolated and purified from the marine green algae Ulothrixflacca using ion-exchange and size-exclusion chromatography. Composition and characteristics analyses showed that UP2-1 was a sulfated glucuronorhamnan consisting of rhamnose and glucuronic acid in a ratio of 2:1 with 21% sulfate content and a molecular weight of 5.0 kDa. Structural properties were determined using desulfation and methylation analyses combined with infrared spectrum (IR), gas chromatography-mass spectrometer (GC-MS) and nuclear magnetic resonance (NMR). The results showed that UP2-1 was a type of ulvan composed of alternate 4-linked-α-L-rhamnose residues (→4)-α-L-Rha(1→) and 4-linked-β-D-glucouronoc acid residues. The sulfate groups were mainly present in the O-3 position of →4)-α-L-Rha(1→. Most (70%) of the rhamnose was sulfated. UP2-1 also had a small amount of →4)-α-L-Rha(1→ branch at the O-2 position of the →4)-α-L-Rha(1→. UP2-1 exhibited significant anticoagulant and immunomodulating activity in vitro. This study demonstrated that the green algae Ulothrix flacca, which is used as a food and traditional marine herb in China, could also be considered as a source of bioactive ulvan.
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Affiliation(s)
- Peipei Li
- Marine School, Ningbo University, 315000 Ningbo, China.
- Zhejiang Mariculture Research Institute, Zhoushan 316000, China.
| | - Songsong Wen
- Shandong Institute of Food and Drug Control, Jinan 250000, China.
| | - Kunlai Sun
- College of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316000, China.
| | - Yuqin Zhao
- College of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316000, China.
| | - Yin Chen
- College of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316000, China.
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Yu P, Pearson CS, Geller HM. Flexible Roles for Proteoglycan Sulfation and Receptor Signaling. Trends Neurosci 2018; 41:47-61. [PMID: 29150096 PMCID: PMC5748001 DOI: 10.1016/j.tins.2017.10.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 10/19/2017] [Accepted: 10/25/2017] [Indexed: 11/25/2022]
Abstract
Proteoglycans (PGs) in the extracellular matrix (ECM) play vital roles in axon growth and navigation, plasticity, and regeneration of injured neurons. Different classes of PGs may support or inhibit cell growth, and their functions are determined in part by highly specific structural features. Among these, the pattern of sulfation on the PG sugar chains is a paramount determinant of a diverse and flexible set of outcomes. Recent studies of PG sulfation illustrate the challenges of attributing biological actions to specific sulfation patterns, and suggest ways in which highly similar molecules may exert opposing effects on neurons. The receptors for PGs, which have yet to be fully characterized, display a similarly nuanced spectrum of effects. Different classes of PG function via overlapping families of receptors and signaling pathways. This enables them to control axon growth and guidance with remarkable specificity, but it poses challenges for determining the precise binding interactions and downstream effects of different PGs and their assorted sulfated epitopes. This review examines existing and emerging evidence for the roles of PG sulfation and receptor interactions in determining how these complex molecules influence neuronal development, growth, and function.
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Affiliation(s)
- Panpan Yu
- Guangdong-Hongkong-Macau Institute of CNS Regeneration; Ministry of Education Joint International Research Laboratory of CNS Regeneration, Jinan University, Guangzhou 510632, China.
| | - Craig S Pearson
- Laboratory of Developmental Neurobiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA; Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Herbert M Geller
- Laboratory of Developmental Neurobiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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The cartilage matrix molecule components produced by human foetal cartilage rudiment cells within scaffolds and the role of exogenous growth factors. Biomaterials 2012; 33:4078-88. [DOI: 10.1016/j.biomaterials.2012.02.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 02/14/2012] [Indexed: 11/18/2022]
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Elucidating glycosaminoglycan-protein-protein interactions using carbohydrate microarray and computational approaches. Proc Natl Acad Sci U S A 2011; 108:9747-52. [PMID: 21628576 DOI: 10.1073/pnas.1102962108] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Glycosaminoglycan polysaccharides play critical roles in many cellular processes, ranging from viral invasion and angiogenesis to spinal cord injury. Their diverse biological activities are derived from an ability to regulate a remarkable number of proteins. However, few methods exist for the rapid identification of glycosaminoglycan-protein interactions and for studying the potential of glycosaminoglycans to assemble multimeric protein complexes. Here, we report a multidisciplinary approach that combines new carbohydrate microarray and computational modeling methodologies to elucidate glycosaminoglycan-protein interactions. The approach was validated through the study of known protein partners for heparan and chondroitin sulfate, including fibroblast growth factor 2 (FGF2) and its receptor FGFR1, the malarial protein VAR2CSA, and tumor necrosis factor-α (TNF-α). We also applied the approach to identify previously undescribed interactions between a specific sulfated epitope on chondroitin sulfate, CS-E, and the neurotrophins, a critical family of growth factors involved in the development, maintenance, and survival of the vertebrate nervous system. Our studies show for the first time that CS is capable of assembling multimeric signaling complexes and modulating neurotrophin signaling pathways. In addition, we identify a contiguous CS-E-binding site by computational modeling that suggests a potential mechanism to explain how CS may promote neurotrophin-tyrosine receptor kinase (Trk) complex formation and neurotrophin signaling. Together, our combined microarray and computational modeling methodologies provide a general, facile means to identify new glycosaminoglycan-protein-protein interactions, as well as a molecular-level understanding of those complexes.
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Suwan K, Hatano S, Kongtawelert P, Pothacharoen P, Watanabe H. Alteration of chondroitin sulfate composition on proteoglycan produced by knock-in mouse embryonic fibroblasts whose versican lacks the A subdomain. Ups J Med Sci 2009; 114:73-81. [PMID: 19396693 PMCID: PMC2852754 DOI: 10.1080/03009730902761722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Versican/proteoglycan-mesenchymal (PG-M) is a large chondroitin sulfate (CS) proteoglycan of the extracellular matrix (ECM) that is constitutively expressed in adult tissues such as dermis and blood vessels. It serves as a structural macromolecule of the ECM, while in embryonic tissue it is transiently expressed at high levels and regulates cell adhesion, migration, proliferation, and differentiation. Knock-in mouse embryonic (Cspg2(Delta3/Delta3)) fibroblasts whose versican lack the A subdomain of the G1 domain exhibit low proliferation rates and acquire senescence. It was suspected that chondroitin sulfate on versican core protein would be altered when the A subdomain was disrupted, so fibroblasts were made from homozygous Cspg2(Delta3/Delta3) mouse embryos to investigate the hypothesis. Analysis of the resulting versican deposition demonstrated that the total versican deposited in the Cspg2(Delta3/Delta3) fibroblasts culture was approximately 50% of that of the wild type (WT), while the versican deposited in the ECM of Cspg2(Delta3/Delta3) fibroblasts culture was 35% of that of the WT, demonstrating the lower capacity of mutant (Cspg2(Delta3/Delta3)) versican deposited in the ECM. The analysis of CS expression in the Cspg2(Delta3/Delta3) fibroblasts culture compared with wild-type fibroblasts showed that the composition of the non-sulfate chondroitin sulfate isomer on the versican core protein increased in the cell layer but decreased in the culture medium. Interestingly, chondroitin sulfate E isomer was found in the culture medium. The amount of CS in the Cspg2(Delta3/Delta3) cell layer of fibroblasts with mutant versican was dramatically decreased, contrasted to the amount in the culture medium, which increased. It was concluded that the disruption of the A subdomain of the versican molecule leads to lowering of the amount of versican deposited in the ECM and the alteration of the composition and content of CS on the versican molecule.
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Affiliation(s)
- Keittisak Suwan
- 1Thailand Excellence Center for Tissue Engineering, Department of Biochemistry, Faculty of Medicine, Chiang Mai UniversityChiang MaiThailand
| | - Sonoko Hatano
- 2Institute for Molecular Science of Medicine, Aichi Medical UniversityAichiJapan
| | - Prachya Kongtawelert
- 1Thailand Excellence Center for Tissue Engineering, Department of Biochemistry, Faculty of Medicine, Chiang Mai UniversityChiang MaiThailand
| | - Peraphan Pothacharoen
- 1Thailand Excellence Center for Tissue Engineering, Department of Biochemistry, Faculty of Medicine, Chiang Mai UniversityChiang MaiThailand
| | - Hideto Watanabe
- 2Institute for Molecular Science of Medicine, Aichi Medical UniversityAichiJapan
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Hayes AJ, Tudor D, Nowell MA, Caterson B, Hughes CE. Chondroitin sulfate sulfation motifs as putative biomarkers for isolation of articular cartilage progenitor cells. J Histochem Cytochem 2007; 56:125-38. [PMID: 17938280 DOI: 10.1369/jhc.7a7320.2007] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Osteoarthritis is a chronic, debilitating joint disease characterized by progressive destruction of articular cartilage. Recently, a number of studies have identified a chondroprogenitor cell population within articular cartilage with significant potential for repair/regeneration. As yet, there are few robust biomarkers of these cells. In this study, we show that monoclonal antibodies recognizing novel chondroitin sulfate sulfation motif epitopes in glycosaminoglycans on proteoglycans can be used to identify metabolically distinct subpopulations of cells specifically within the superficial zone of the tissue and that flow cytometric analysis can recognize these cell subpopulations. Fluorochrome co-localization analysis suggests that the chondroitin sulfate sulphation motifs are associated with a range of cell and extracellular matrix proteoglycans within the stem cell niche that include perlecan and aggrecan but not versican. The unique distributions of these sulphation motifs within the microenvironment of superficial zone chondrocytes, seems to designate early stages of stem/progenitor cell differentiation and is consistent with these molecules playing a functional role in regulating aspects of chondrogenesis. The isolation and further characterization of these cells will lead to an improved understanding of the role novel chondroitin sulfate sulfation plays in articular cartilage development and may contribute significantly to the field of articular cartilage repair.
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Affiliation(s)
- Anthony J Hayes
- Connective Tissue Biology Laboratory and Cardiff Institute of Tissue Engineering and Repair, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3US, Wales, United Kingdom
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Brandl N, Holzmann J, Schabus R, Huettinger M. Effects of chondroitin sulfate on the cellular metabolism. ADVANCES IN PHARMACOLOGY 2007; 53:433-47. [PMID: 17239779 DOI: 10.1016/s1054-3589(05)53021-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- N Brandl
- Medical University Vienna, Center Physiology and Pathophysiology, 1090 Vienna, Währingerstrasse 10 Austria
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Holzmann J, Brandl N, Zemann A, Schabus R, Marlovits S, Cowburn R, Huettinger M. Assorted effects of TGFbeta and chondroitinsulfate on p38 and ERK1/2 activation levels in human articular chondrocytes stimulated with LPS. Osteoarthritis Cartilage 2006; 14:519-25. [PMID: 16503173 DOI: 10.1016/j.joca.2005.12.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Accepted: 12/17/2005] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Inadequate cellular response of chondrocytes to stress frequently terminates in osteoarthritis (OA). Adequate response is fundamentally modulated by concerted cytokine signaling events, directing degradation and synthesis of cartilage on articular surfaces where and whenever necessary. Transforming growth factor (TGF)beta is a prominent mediator in cartilage anabolism, although particular catabolic activities are occasionally reported. Clearly, before the TGFbeta signal gets through to the gene regulatory machinery, cross talk with modulators occurs. METHOD We tested the hypothesis whether chondroitinsulfate (CS) modulates cell signaling. TGFbeta and/or soluble CS was added to human articular chondrocytes (HACs) and activation of p38 and extracellular signal related kinase (ERK)1/2 was determined by immunoblot analysis. Expression levels of mRNA of matrix metalloproteinase (MMP)-2, -3 and -13 were determined by real-time polymerase chain reaction (PCR). RESULTS No significant effects were observed unless cells were stimulated with lipopolysaccharide (LPS), invigorating catabolic metabolism in chondrocytes. LPS effects, however, were profoundly modulated by TGFbeta, CS and both applied in combination. Most prominent, the silencing of p38 stress signal by CS was superimposable to that of TGFbeta. Phospho-ERK1/2 levels were raised by TGFbeta three-fold over LPS induced levels. In contrast, CS treatment, alone or combined with TGFbeta, reduced phosphorylation significantly below LPS induced levels. Finally, suppression of LPS induced MMP-13 mRNA levels resulted with CS. CONCLUSION Soluble CS modulates signaling events in chondrocytes concurrent with MMP-13 down regulation. The effects observed suggest a feedback signaling mechanism cross talking with TGFbeta-signal pathways and may serve an explanation, on the cellular level, for the beneficial effects found in clinical studies with pharmacologic application of CS.
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Affiliation(s)
- J Holzmann
- Zentrum Physiology and Pathophysiology, A-1090 Wien, Währingerstr. 10/13, Austria
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Abstract
Proteoglycans (PGs) have been suggested to work as receptors in lipoprotein uptake mechanisms. An interaction between apolipoprotein E (apoE) and glucosaminoglycans (GAG), polysaccharides linked to proteoglycans, has been proposed in this pathway. At the same time, proteoglycans, apoE as well as lipoprotein receptors have been reported to be constituents of amyloid plaques, one hallmark of Alzheimer's disease. With this study, we are the first to investigate the interaction between beta very low density lipoprotein (beta-VLDL) and a neuronal highly abundant GAG, chondroitin sulphate (CS), comparing hippocampal neurons, expressing high levels of low density lipoprotein receptor related protein (LRP) and U373 astrocytoma cells, highly positive for the low density lipoprotein receptor (LDLR). We were able demonstrate that degradation of chondroitin sulphate proteoglycans (CSPGs) with chondroitinase ABC resulted in reduced (125)I-beta-VLDL uptake. We showed that externally added CSs compete with internalization of beta-VLDL. The effect was found to be dose-dependent, but was influenced neither by cell type, nor receptor type. The position of sulphation of added CSs showed only a slight influence. The data generated suggested an interaction between apolipoproteins and soluble CSs; therefore, 3H-cholesterol linked to apoE was coadministered with CSs to the cells. The results revealed that apoE bound, but no unbound cholesterol, was reduced in cellular internalization, suggesting that CSPGs may be involved in lipoprotein uptake in the intact brain, mediated, at least in part, by apoE.
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Affiliation(s)
- Alfred Rapp
- MedUniWien, Center of Physiology and Pathophysiology, Department of Medical Chemistry, Währingerstrasse 10, 1090 Vienna, Austria.
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