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Hunter C, Derksen T, Makhsous S, Doll M, Perez SR, Scott NE, Willis LM. Site-specific immobilization of the endosialidase reveals QSOX2 is a novel polysialylated protein. Glycobiology 2024; 34:cwae026. [PMID: 38489772 PMCID: PMC11031136 DOI: 10.1093/glycob/cwae026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 03/04/2024] [Accepted: 03/13/2024] [Indexed: 03/17/2024] Open
Abstract
Polysialic acid (polySia) is a linear polymer of α2,8-linked sialic acid residues that is of fundamental biological interest due to its pivotal roles in the regulation of the nervous, immune, and reproductive systems in healthy human adults. PolySia is also dysregulated in several chronic diseases, including cancers and mental health disorders. However, the mechanisms underpinning polySia biology in health and disease remain largely unknown. The polySia-specific hydrolase, endoneuraminidase NF (EndoN), and the catalytically inactive polySia lectin EndoNDM, have been extensively used for studying polySia. However, EndoN is heat stable and remains associated with cells after washing. When studying polySia in systems with multiple polysialylated species, the residual EndoN that cannot be removed confounds data interpretation. We developed a strategy for site-specific immobilization of EndoN on streptavidin-coated magnetic beads. We showed that immobilizing EndoN allows for effective removal of the enzyme from samples, while retaining hydrolase activity. We used the same strategy to immobilize the polySia lectin EndoNDM, which enabled the enrichment of polysialylated proteins from complex mixtures such as serum for their identification via mass spectrometry. We used this methodology to identify a novel polysialylated protein, QSOX2, which is secreted from the breast cancer cell line MCF-7. This method of site-specific immobilization can be utilized for other enzymes and lectins to yield insight into glycobiology.
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Affiliation(s)
- Carmanah Hunter
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Tahlia Derksen
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Sogand Makhsous
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Matt Doll
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Samantha Rodriguez Perez
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, VIC 3000, Australia
| | - Lisa M Willis
- Department of Biological Sciences, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
- Department of Medical Microbiology and Immunology, University of Alberta, 116 St & 85 Ave, Edmonton, AB, T6G 2R3, Canada
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2
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Peterson SL, Krishnan A, Patel D, Khanehzar A, Lad A, Shaughnessy J, Ram S, Callanan D, Kunimoto D, Genead MA, Tolentino MJ. PolySialic Acid Nanoparticles Actuate Complement-Factor-H-Mediated Inhibition of the Alternative Complement Pathway: A Safer Potential Therapy for Age-Related Macular Degeneration. Pharmaceuticals (Basel) 2024; 17:517. [PMID: 38675477 PMCID: PMC11053938 DOI: 10.3390/ph17040517] [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: 03/06/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
The alternative pathway of the complement system is implicated in the etiology of age-related macular degeneration (AMD). Complement depletion with pegcetacoplan and avacincaptad pegol are FDA-approved treatments for geographic atrophy in AMD that, while effective, have clinically observed risks of choroidal neovascular (CNV) conversion, optic neuritis, and retinal vasculitis, leaving room for other equally efficacious but safer therapeutics, including Poly Sialic acid (PSA) nanoparticle (PolySia-NP)-actuated complement factor H (CFH) alternative pathway inhibition. Our previous paper demonstrated that PolySia-NP inhibits pro-inflammatory polarization and cytokine release. Here, we extend these findings by investigating the therapeutic potential of PolySia-NP to attenuate the alternative complement pathway. First, we show that PolySia-NP binds CFH and enhances affinity to C3b. Next, we demonstrate that PolySia-NP treatment of human serum suppresses alternative pathway hemolytic activity and C3b deposition. Further, we show that treating human macrophages with PolySia-NP is non-toxic and reduces markers of complement activity. Finally, we describe PolySia-NP-treatment-induced decreases in neovascularization and inflammatory response in a laser-induced CNV mouse model of neovascular AMD. In conclusion, PolySia-NP suppresses alternative pathway complement activity in human serum, human macrophage, and mouse CNV without increasing neovascularization.
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Affiliation(s)
- Sheri L. Peterson
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Anitha Krishnan
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Diyan Patel
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Ali Khanehzar
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Amit Lad
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA; (J.S.); (S.R.)
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA; (J.S.); (S.R.)
| | - David Callanan
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Derek Kunimoto
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Mohamed A. Genead
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
| | - Michael J. Tolentino
- Aviceda Therapeutics Inc., Cambridge, MA 02142, USA; (A.K.); (A.L.); (D.C.); (D.K.); (M.A.G.)
- Department of Ophthalmology, University of Central Florida School of Medicine, Orlando, FL 32827, USA
- Department of Ophthalmology, Orlando College of Osteopathic Medicine, Orlando, FL 34787, USA
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3
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Krishnan A, Callanan DG, Sendra VG, Lad A, Christian S, Earla R, Khanehzar A, Tolentino AJ, Vailoces VAS, Greene MK, Scott CJ, Kunimoto DY, Hassan TS, Genead MA, Tolentino MJ. Comprehensive Ocular and Systemic Safety Evaluation of Polysialic Acid-Decorated Immune Modulating Therapeutic Nanoparticles (PolySia-NPs) to Support Entry into First-in-Human Clinical Trials. Pharmaceuticals (Basel) 2024; 17:481. [PMID: 38675441 PMCID: PMC11054942 DOI: 10.3390/ph17040481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 03/27/2024] [Accepted: 04/02/2024] [Indexed: 04/28/2024] Open
Abstract
An inflammation-resolving polysialic acid-decorated PLGA nanoparticle (PolySia-NP) has been developed to treat geographic atrophy/age-related macular degeneration and other conditions caused by macrophage and complement over-activation. While PolySia-NPs have demonstrated pre-clinical efficacy, this study evaluated its systemic and intraocular safety. PolySia-NPs were evaluated in vitro for mutagenic activity using Salmonella strains and E. coli, with and without metabolic activation; cytotoxicity was evaluated based on its interference with normal mitosis. PolySia-NPs were administered intravenously in CD-1 mice and Sprague Dawley rats and assessed for survival and toxicity. Intravitreal (IVT) administration in Dutch Belted rabbits and non-human primates was assessed for ocular or systemic toxicity. In vitro results indicate that PolySia-NPs did not induce mutagenicity or cytotoxicity. Intravenous administration did not show clastogenic activity, effects on survival, or toxicity. A single intravitreal (IVT) injection and two elevated repeat IVT doses of PolySia-NPs separated by 7 days in rabbits showed no signs of systemic or ocular toxicity. A single IVT inoculation of PolySia-NPs in non-human primates demonstrated no adverse clinical or ophthalmological effects. The demonstration of systemic and ocular safety of PolySia-NPs supports its advancement into human clinical trials as a promising therapeutic approach for systemic and retinal degenerative diseases caused by chronic immune activation.
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Affiliation(s)
- Anitha Krishnan
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
| | - David G. Callanan
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
| | - Victor G. Sendra
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
| | - Amit Lad
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
| | - Sunny Christian
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
| | - Ravinder Earla
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
| | - Ali Khanehzar
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
| | - Andrew J. Tolentino
- Department of Biology, University of California Berkeley, Berkeley, CA 94720, USA;
| | | | - Michelle K. Greene
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
- The Patrick G. Johnston Centre for Cancer Research, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast BT9 7AE, UK
| | - Christopher J. Scott
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
- The Patrick G. Johnston Centre for Cancer Research, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast BT9 7AE, UK
| | - Derek Y. Kunimoto
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
| | - Tarek S. Hassan
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
- Oakland University William Beaumont School of Medicine, Royal Oaks, MI 48067, USA
| | - Mohamed A. Genead
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
| | - Michael J. Tolentino
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (D.G.C.); (A.L.); (S.C.); (R.E.); (A.K.); (M.K.G.); (C.J.S.); (D.Y.K.); (T.S.H.); (M.A.G.)
- Department of Ophthalmology, University of Central Florida School of Medicine, Orlando, FL 32827, USA
- Department of Ophthalmology, Orlando College of Osteopathic Medicine, Orlando, FL 34787, USA
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4
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Wißfeld J, Abou Assale T, Cuevas-Rios G, Liao H, Neumann H. Therapeutic potential to target sialylation and SIGLECs in neurodegenerative and psychiatric diseases. Front Neurol 2024; 15:1330874. [PMID: 38529039 PMCID: PMC10961342 DOI: 10.3389/fneur.2024.1330874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 02/21/2024] [Indexed: 03/27/2024] Open
Abstract
Sialic acids, commonly found as the terminal carbohydrate on the glycocalyx of mammalian cells, are pivotal checkpoint inhibitors of the innate immune system, particularly within the central nervous system (CNS). Sialic acid-binding immunoglobulin-like lectins (SIGLECs) expressed on microglia are key players in maintaining microglial homeostasis by recognizing intact sialylation. The finely balanced sialic acid-SIGLEC system ensures the prevention of excessive and detrimental immune responses in the CNS. However, loss of sialylation and SIGLEC receptor dysfunctions contribute to several chronic CNS diseases. Genetic variants of SIGLEC3/CD33, SIGLEC11, and SIGLEC14 have been associated with neurodegenerative diseases such as Alzheimer's disease, while sialyltransferase ST8SIA2 and SIGLEC4/MAG have been linked to psychiatric diseases such as schizophrenia, bipolar disorders, and autism spectrum disorders. Consequently, immune-modulatory functions of polysialic acids and SIGLEC binding antibodies have been exploited experimentally in animal models of Alzheimer's disease and inflammation-induced CNS tissue damage, including retinal damage. While the potential of these therapeutic approaches is evident, only a few therapies to target either sialylation or SIGLEC receptors have been tested in patient clinical trials. Here, we provide an overview of the critical role played by the sialic acid-SIGLEC axis in shaping microglial activation and function within the context of neurodegeneration and synaptopathies and discuss the current landscape of therapies that target sialylation or SIGLECs.
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Affiliation(s)
- Jannis Wißfeld
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Tawfik Abou Assale
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital Bonn, University of Bonn, Bonn, Germany
| | - German Cuevas-Rios
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Huan Liao
- Florey Institute of Neuroscience and Mental Health, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital Bonn, University of Bonn, Bonn, Germany
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5
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Tsioti I, Steiner BL, Escher P, Zinkernagel MS, Benz PM, Kokona D. Systemic Lipopolysaccharide Exposure Exacerbates Choroidal Neovascularization in Mice. Ocul Immunol Inflamm 2024; 32:19-30. [PMID: 36441988 DOI: 10.1080/09273948.2022.2147547] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 11/08/2022] [Indexed: 11/29/2022]
Abstract
This study aims to investigate the effect of a systemic lipopolysaccharide (LPS) stimulus in the course of laser-induced choroidal neovascularization (CNV) in C57BL/6 J mice. A group of CNV-subjected mice received 1 mg/kg LPS via the tail vein immediately after CNV induction. Mouse eyes were monitored in vivo with fluorescein angiography for 2 weeks. In situ hybridization and flow cytometry were performed in the retina at different time points. LPS led to increased fluorescein leakage 3 days after CNV, correlated with a large influx of monocyte-derived macrophages and increase of pro-inflammatory microglia/macrophages in the retina. Additionally, LPS enhanced Vegfα mRNA expression by Glul-expressing cells but not Aif1 positive microglia/macrophages in the laser lesion. These findings suggest that systemic LPS exposure has transient detrimental effects in the course of CNV through activation of microglia/macrophages to a pro-inflammatory phenotype and supports the important role of these cells in the CNV course.
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Affiliation(s)
- Ioanna Tsioti
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Beatrice L Steiner
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Pascal Escher
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Martin S Zinkernagel
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
| | - Peter M Benz
- Department of CardioMetabolic Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Despina Kokona
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
- Department of BioMedical Research, University of Bern, Bern, Switzerland
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6
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Tolentino MJ, Tolentino AJ, Tolentino EM, Krishnan A, Genead MA. Sialic Acid Mimetic Microglial Sialic Acid-Binding Immunoglobulin-like Lectin Agonism: Potential to Restore Retinal Homeostasis and Regain Visual Function in Age-Related Macular Degeneration. Pharmaceuticals (Basel) 2023; 16:1735. [PMID: 38139861 PMCID: PMC10747662 DOI: 10.3390/ph16121735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/29/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Age-related macular degeneration (AMD), a leading cause of visual loss and dysfunction worldwide, is a disease initiated by genetic polymorphisms that impair the negative regulation of complement. Proteomic investigation points to altered glycosylation and loss of Siglec-mediated glyco-immune checkpoint parainflammatory and inflammatory homeostasis as the main determinant for the vision impairing complications of macular degeneration. The effect of altered glycosylation on microglial maintained retinal para-inflammatory homeostasis and eventual recruitment and polarization of peripheral blood monocyte-derived macrophages (PBMDMs) into the retina can explain the phenotypic variability seen in this clinically heterogenous disease. Restoring glyco-immune checkpoint control with a sialic acid mimetic agonist targeting microglial/macrophage Siglecs to regain retinal para-inflammatory and inflammatory homeostasis is a promising therapeutic that could halt the progression of and improve visual function in all stages of macular degeneration.
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Affiliation(s)
- Michael J. Tolentino
- Department of Ophthalmology, University of Central Florida College of Medicine, Orlando, FL 32827, USA
- Department of Ophthalmology, Orlando College of Osteopathic Medicine, Orlando, FL 34787, USA
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (M.A.G.)
| | - Andrew J. Tolentino
- Department of Biology, University of California Berkeley, Berkeley, CA 94720, USA;
| | | | - Anitha Krishnan
- Aviceda Therapeutics, Cambridge, MA 02142, USA; (A.K.); (M.A.G.)
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7
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Krishnan A, Sendra VG, Patel D, Lad A, Greene MK, Smyth P, Gallaher SA, Herron ÚM, Scott CJ, Genead M, Tolentino M. PolySialic acid-nanoparticles inhibit macrophage mediated inflammation through Siglec agonism: a potential treatment for age related macular degeneration. Front Immunol 2023; 14:1237016. [PMID: 38045700 PMCID: PMC10690618 DOI: 10.3389/fimmu.2023.1237016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 10/23/2023] [Indexed: 12/05/2023] Open
Abstract
Age-related macular degeneration (AMD) is a chronic, progressive retinal disease characterized by an inflammatory response mediated by activated macrophages and microglia infiltrating the inner layer of the retina. In this study, we demonstrate that inhibition of macrophages through Siglec binding in the AMD eye can generate therapeutically useful effects. We show that Siglecs-7, -9 and -11 are upregulated in AMD associated M0 and M1 macrophages, and that these can be selectively targeted using polysialic acid (PolySia)-nanoparticles (NPs) to control dampen AMD-associated inflammation. In vitro studies showed that PolySia-NPs bind to macrophages through human Siglecs-7, -9, -11 as well as murine ortholog Siglec-E. Following treatment with PolySia-NPs, we observed that the PolySia-NPs bound and agonized the macrophage Siglecs resulting in a significant decrease in the secretion of IL-6, IL-1β, TNF-α and VEGF, and an increased secretion of IL-10. In vivo intravitreal (IVT) injection of PolySia-NPs was found to be well-tolerated and safe making it effective in preventing thinning of the retinal outer nuclear layer (ONL), inhibiting macrophage infiltration, and restoring electrophysiological retinal function in a model of bright light-induced retinal degeneration. In a clinically validated, laser-induced choroidal neovascularization (CNV) model of exudative AMD, PolySia-NPs reduced the size of neovascular lesions with associated reduction in macrophages. The PolySia-NPs described herein are therefore a promising therapeutic strategy for repolarizing pro-inflammatory macrophages to a more anti-inflammatory, non-angiogenic phenotype, which play a key role in the pathophysiology of non-exudative AMD.
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Affiliation(s)
| | | | - Diyan Patel
- Aviceda Therapeutics Inc., Cambridge, MA, United States
| | - Amit Lad
- Aviceda Therapeutics Inc., Cambridge, MA, United States
| | - Michelle K. Greene
- Aviceda Therapeutics Inc., Cambridge, MA, United States
- The Patrick G Johnston Centre for Cancer Research, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Peter Smyth
- Aviceda Therapeutics Inc., Cambridge, MA, United States
- The Patrick G Johnston Centre for Cancer Research, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Samantha A. Gallaher
- The Patrick G Johnston Centre for Cancer Research, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Úna M. Herron
- Aviceda Therapeutics Inc., Cambridge, MA, United States
- The Patrick G Johnston Centre for Cancer Research, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Christopher J. Scott
- Aviceda Therapeutics Inc., Cambridge, MA, United States
- The Patrick G Johnston Centre for Cancer Research, School of Medicine, Dentistry & Biomedical Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | | | - Michael Tolentino
- Aviceda Therapeutics Inc., Cambridge, MA, United States
- Department of Ophthalmology, University of Central Florida School of Medicine, Orlando, FL, United States
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8
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Schröder LJ, Thiesler H, Gretenkort L, Möllenkamp TM, Stangel M, Gudi V, Hildebrandt H. Polysialic acid promotes remyelination in cerebellar slice cultures by Siglec-E-dependent modulation of microglia polarization. Front Cell Neurosci 2023; 17:1207540. [PMID: 37492129 PMCID: PMC10365911 DOI: 10.3389/fncel.2023.1207540] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 06/21/2023] [Indexed: 07/27/2023] Open
Abstract
Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system. Spontaneous restoration of myelin after demyelination occurs, but its efficiency declines during disease progression. Efficient myelin repair requires fine-tuning inflammatory responses by brain-resident microglia and infiltrating macrophages. Accordingly, promising therapeutic strategies aim at controlling inflammation to promote remyelination. Polysialic acid (polySia) is a polymeric glycan with variable chain lengths, presented as a posttranslational modification on select protein carriers. PolySia emerges as a negative regulator of inflammatory microglia and macrophage activation and has been detected on oligodendrocyte precursors and reactive astrocytes in multiple sclerosis lesions. As shown recently, polySia-modified proteins can also be released by activated microglia, and the intrinsically released protein-bound and exogenously applied free polySia were equally able to attenuate proinflammatory microglia activation via the inhibitory immune receptor Siglec-E. In this study, we explore polySia as a candidate substance for promoting myelin regeneration by immunomodulation. Lysophosphatidylcholine-induced demyelination of organotypic cerebellar slice cultures was used as an experimental model to analyze the impact of polySia with different degrees of polymerization (DP) on remyelination and inflammation. In lysophosphatidylcholine-treated cerebellar slice cultures, polySia-positive cells were abundant during demyelination but largely reduced during remyelination. Based on the determination of DP24 as the minimal polySia chain length required for the inhibition of inflammatory BV2 microglia activation, pools with short and long polySia chains (DP8-14 and DP24-30) were generated and applied to slice cultures during remyelination. Unlike DP8-14, treatment with DP24-30 significantly improved remyelination, increased arginase-1-positive microglia ratios, and reduced the production of nitric oxide in wildtype, but not in Siglec-E-deficient slice cultures. In vitro differentiation of oligodendrocytes was not affected by DP24-30. Collectively, these results suggest a beneficial effect of exogenously applied polySia DP24-30 on remyelination by Siglec-E-dependent microglia regulation.
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Affiliation(s)
- Lara-Jasmin Schröder
- Clinic for Neurology, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience Hannover, Hannover, Germany
| | - Hauke Thiesler
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Lina Gretenkort
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | | | - Martin Stangel
- Center for Systems Neuroscience Hannover, Hannover, Germany
- Translational Medicine, Novartis Institute for Biomedical Research, Novartis, Basel, Switzerland
| | - Viktoria Gudi
- Clinic for Neurology, Hannover Medical School, Hannover, Germany
| | - Herbert Hildebrandt
- Center for Systems Neuroscience Hannover, Hannover, Germany
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
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9
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Gretenkort L, Thiesler H, Hildebrandt H. Neuroimmunomodulatory properties of polysialic acid. Glycoconj J 2023; 40:277-294. [PMID: 37171513 DOI: 10.1007/s10719-023-10120-z] [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: 11/15/2022] [Revised: 11/16/2022] [Accepted: 05/02/2023] [Indexed: 05/13/2023]
Abstract
Polymeric sialic acid (polysialic acid, polySia) is a remarkable posttranslational modification of only few select proteins. The major, and most prominent polySia protein carrier is the neural cell adhesion molecule NCAM. Here, the key functions of polySia are to regulate interactions of NCAM and to balance cellular interactions in brain development and plasticity. During recent years, however, increasing evidence points towards a role of polySia in the modulation of immune responses. These immunomodulatory functions can be mediated by polySia on proteins other than NCAM, presented either on the cell surface or released into the extracellular space. This perspective review summarizes our current knowledge and addresses major open questions on polySia and polySia receptors in modulating innate immune responses in the brain.
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Affiliation(s)
- Lina Gretenkort
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
| | - Hauke Thiesler
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
| | - Herbert Hildebrandt
- Institute of Clinical Biochemistry, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
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10
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Siew JJ, Chern Y, Khoo KH, Angata T. Roles of Siglecs in neurodegenerative diseases. Mol Aspects Med 2023; 90:101141. [PMID: 36089405 DOI: 10.1016/j.mam.2022.101141] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 02/08/2023]
Abstract
Microglia are resident myeloid cells in the central nervous system (CNS) with a unique developmental origin, playing essential roles in developing and maintaining the CNS environment. Recent studies have revealed the involvement of microglia in neurodegenerative diseases, such as Alzheimer's disease, through the modulation of neuroinflammation. Several members of the Siglec family of sialic acid recognition proteins are expressed on microglia. Since the discovery of the genetic association between a polymorphism in the CD33 gene and late-onset Alzheimer's disease, significant efforts have been made to elucidate the molecular mechanism underlying the association between the polymorphism and Alzheimer's disease. Furthermore, recent studies have revealed additional potential associations between Siglecs and Alzheimer's disease, implying that the reduced signal from inhibitory Siglec may have an overall protective effect in lowering the disease risk. Evidences suggesting the involvement of Siglecs in other neurodegenerative diseases are also emerging. These findings could help us predict the roles of Siglecs in other neurodegenerative diseases. However, little is known about the functionally relevant Siglec ligands in the brain, which represents a new frontier. Understanding how microglial Siglecs and their ligands in CNS contribute to the regulation of CNS homeostasis and pathogenesis of neurodegenerative diseases may provide us with a new avenue for disease prevention and intervention.
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Affiliation(s)
- Jian Jing Siew
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yijuang Chern
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Kay-Hooi Khoo
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
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11
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Zhou W, Zhou Y, He J, Rao Y, Fei P, Li J. TREM2 deficiency in microglia accelerates photoreceptor cell death and immune cell infiltration following retinal detachment. Cell Death Dis 2023; 14:219. [PMID: 36977680 PMCID: PMC10050330 DOI: 10.1038/s41419-023-05735-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/03/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023]
Abstract
Retinal detachment (RD) occurs in several major retinal conditions and often causes irreversible vision loss due to photoreceptor cell death. Retinal residential microglial cells are activated following RD and participate in photoreceptor cell death via direct phagocytosis and the regulation of inflammatory responses. Triggering receptor expressed on myeloid cells 2 (TREM2) is an innate immune receptor exclusively expressed on microglial cells in the retina, and has been reported to affect microglial cell homeostasis, phagocytosis and inflammatory responses in the brain. In this study, increased expression of multiple cytokines and chemokines in the neural retina was observed starting at 3 h following RD. Trem2 knockout (Trem2-/-) mice exhibited significantly more photoreceptor cell death than wild-type controls at 3 days after RD, and the number of TUNEL positive photoreceptor cells progressively decreased from day 3 to day 7 post-RD. A significant thinning of the outer nuclear layer (ONL), with multiple folds was observed in the Trem2-/- mice at 3 days post-RD. Trem2 deficiency reduced microglial cell infiltration and phagocytosis of stressed photoreceptors. There were more neutrophils in Trem2-/- retina following RD than in controls. Using purified microglial cells, we found Trem2 knockout is associated with increased CXCL12 expression. The aggravated photoreceptor cell death was largely reversed by blocking the CXCL12-CXCR4 mediated chemotaxis in Trem2-/- mice after RD. Our findings suggested that retinal microglia are protective in preventing further photoreceptor cell death following RD by phagocytosing presumably stressed photoreceptor cells and by regulating inflammatory responses. TREM2 is largely responsible for such protective effect and CXCL12 plays an important role in regulating neutrophil infiltration after RD. Collectively, our study pinpointed TREM2 as a potential target of microglial cells to ameliorate RD-induced photoreceptor cell death.
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Affiliation(s)
- Wenchuan Zhou
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China
| | - Yutong Zhou
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China
| | - Jincan He
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China
| | - Yuqing Rao
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China
| | - Ping Fei
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.
| | - Jing Li
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.
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12
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John MC, Quinn J, Hu ML, Cehajic-Kapetanovic J, Xue K. Gene-agnostic therapeutic approaches for inherited retinal degenerations. Front Mol Neurosci 2023; 15:1068185. [PMID: 36710928 PMCID: PMC9881597 DOI: 10.3389/fnmol.2022.1068185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/12/2022] [Indexed: 01/11/2023] Open
Abstract
Inherited retinal diseases (IRDs) are associated with mutations in over 250 genes and represent a major cause of irreversible blindness worldwide. While gene augmentation or gene editing therapies could address the underlying genetic mutations in a small subset of patients, their utility remains limited by the great genetic heterogeneity of IRDs and the costs of developing individualised therapies. Gene-agnostic therapeutic approaches target common pathogenic pathways that drive retinal degeneration or provide functional rescue of vision independent of the genetic cause, thus offering potential clinical benefits to all IRD patients. Here, we review the key gene-agnostic approaches, including retinal cell reprogramming and replacement, neurotrophic support, immune modulation and optogenetics. The relative benefits and limitations of these strategies and the timing of clinical interventions are discussed.
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Affiliation(s)
- Molly C. John
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Joel Quinn
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Monica L. Hu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Kanmin Xue
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
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13
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Musolf AM, Haarman AEG, Luben RN, Ong JS, Patasova K, Trapero RH, Marsh J, Jain I, Jain R, Wang PZ, Lewis DD, Tedja MS, Iglesias AI, Li H, Cowan CS, Biino G, Klein AP, Duggal P, Mackey DA, Hayward C, Haller T, Metspalu A, Wedenoja J, Pärssinen O, Cheng CY, Saw SM, Stambolian D, Hysi PG, Khawaja AP, Vitart V, Hammond CJ, van Duijn CM, Verhoeven VJM, Klaver CCW, Bailey-Wilson JE. Rare variant analyses across multiethnic cohorts identify novel genes for refractive error. Commun Biol 2023; 6:6. [PMID: 36596879 PMCID: PMC9810640 DOI: 10.1038/s42003-022-04323-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/30/2022] [Indexed: 01/05/2023] Open
Abstract
Refractive error, measured here as mean spherical equivalent (SER), is a complex eye condition caused by both genetic and environmental factors. Individuals with strong positive or negative values of SER require spectacles or other approaches for vision correction. Common genetic risk factors have been identified by genome-wide association studies (GWAS), but a great part of the refractive error heritability is still missing. Some of this heritability may be explained by rare variants (minor allele frequency [MAF] ≤ 0.01.). We performed multiple gene-based association tests of mean Spherical Equivalent with rare variants in exome array data from the Consortium for Refractive Error and Myopia (CREAM). The dataset consisted of over 27,000 total subjects from five cohorts of Indo-European and Eastern Asian ethnicity. We identified 129 unique genes associated with refractive error, many of which were replicated in multiple cohorts. Our best novel candidates included the retina expressed PDCD6IP, the circadian rhythm gene PER3, and P4HTM, which affects eye morphology. Future work will include functional studies and validation. Identification of genes contributing to refractive error and future understanding of their function may lead to better treatment and prevention of refractive errors, which themselves are important risk factors for various blinding conditions.
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Affiliation(s)
- Anthony M Musolf
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Annechien E G Haarman
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Robert N Luben
- MRC Epidemiology, University of Cambridge School of Clinical Medicine, Cambridge, UK
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Jue-Sheng Ong
- Statistical Genetics Laboratory, Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Karina Patasova
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - Rolando Hernandez Trapero
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Joseph Marsh
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Ishika Jain
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Riya Jain
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Paul Zhiping Wang
- Institute for Biomedical Sciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Deyana D Lewis
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA
| | - Milly S Tedja
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Adriana I Iglesias
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Hengtong Li
- Data Science Unit, Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Cameron S Cowan
- Institute for Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
| | - Ginevra Biino
- Institute of Molecular Genetics, National Research Council of Italy, Pavia, Italy
| | - Alison P Klein
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Priya Duggal
- The Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - David A Mackey
- Centre for Ophthalmology and Visual Science, Lions Eye Institute, University of Western Australia, Perth, WA, Australia
| | - Caroline Hayward
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Toomas Haller
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Andres Metspalu
- Estonian Genome Center, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Juho Wedenoja
- Department of Ophthalmology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Department of Public Health, University of Helsinki, Helsinki, Finland
| | - Olavi Pärssinen
- Department of Ophthalmology, Central Hospital of Central Finland, Jyväskylä, Finland
- Gerontology Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Ching-Yu Cheng
- Centre for Quantitative Medicine, DUKE-National University of Singapore, Singapore, Singapore
- Ocular Epidemiology Research Group, Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Seang-Mei Saw
- Saw Swee Hock School of Public Health, National University Health Systems, National University of Singapore, Singapore, Singapore
- Myopia Research Group, Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Dwight Stambolian
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Pirro G Hysi
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - Anthony P Khawaja
- MRC Epidemiology, University of Cambridge School of Clinical Medicine, Cambridge, UK
- NIHR Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Veronique Vitart
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Western General Hospital, Edinburgh, UK
| | - Christopher J Hammond
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | | | - Virginie J M Verhoeven
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands.
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.
| | - Caroline C W Klaver
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands.
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
- Institute for Molecular and Clinical Ophthalmology Basel, Basel, Switzerland.
- Department of Ophthalmology, Radboud University Medical Centre, Nijmegen, The Netherlands.
| | - Joan E Bailey-Wilson
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Baltimore, MD, USA.
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14
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Zhou Z, Jing Y, Niu Y, Chang T, Sun J, Guo C, Wang Y, Dou G. Distinguished Functions of Microglia in the Two Stages of Oxygen-Induced Retinopathy: A Novel Target in the Treatment of Ischemic Retinopathy. LIFE (BASEL, SWITZERLAND) 2022; 12:life12101676. [PMID: 36295111 PMCID: PMC9604577 DOI: 10.3390/life12101676] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/17/2022]
Abstract
Microglia is the resident immune cell in the retina, playing the role of immune surveillance in a traditional concept. With the heated focus on the mechanisms of microglia in pathological conditions, more and more functions of microglia have been discovered. Although the regulating role of microglia has been explored in ischemic retinopathy, little is known about its mechanisms in the different stages of the pathological process. Here, we removed microglia in the oxygen-induced retinopathy model by PLX5622 and revealed that the removal of activated microglia reduced pathological angiogenesis in the early stage after ischemic insult and alleviated the over-apoptosis of photoreceptors in the vessel remodeling phase. Our results indicated that microglia might play distinguished functions in the angiogenic and remodeling stages, and that the inhibition of microglia might be a promising target in the future treatment of ischemic retinopathy.
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Affiliation(s)
| | | | | | | | | | | | - Yusheng Wang
- Correspondence: (Y.W.); (G.D.); Tel.: +86-029-84775371 (Y.W.); +86-029-84771273 (G.D.)
| | - Guorui Dou
- Correspondence: (Y.W.); (G.D.); Tel.: +86-029-84775371 (Y.W.); +86-029-84771273 (G.D.)
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15
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Tabel M, Wolf A, Szczepan M, Xu H, Jägle H, Moehle C, Chen M, Langmann T. Genetic targeting or pharmacological inhibition of galectin-3 dampens microglia reactivity and delays retinal degeneration. J Neuroinflammation 2022; 19:229. [PMID: 36115971 PMCID: PMC9482176 DOI: 10.1186/s12974-022-02589-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 09/07/2022] [Indexed: 11/15/2022] Open
Abstract
Background Dysfunctional humoral and cellular innate immunity are key components in the development and progression of age-related macular degeneration (AMD). Specifically, chronically activated microglia and their disturbed regulatory system contribute to retinal degeneration. Galectin-3, a β-galactose binding protein, is a potent driver of macrophage and microglia activation and has been implicated in neuroinflammation, including neurodegenerative diseases of the brain. Here, we hypothesized that genetic deficiency of galectin-3 or its modulation via TD139 dampens mononuclear phagocyte reactivity and delays retinal degeneration. Methods Galectin-3 expression in AMD patients was analyzed by immunohistochemical stainings. Galectin-3 knockout and BALB/cJ mice were exposed to white bright light with an intensity of 15,000 lux for 1 h and Cx3cr1GFP/+ mice to focal blue light of 50,000 lux for 10 min. BALB/cJ and Cx3cr1GFP/+ mice received intraperitoneal injections of 15 mg/kg TD139 or vehicle for five consecutive days, starting one day prior to light exposure. The effects of galectin-3 deficiency or inhibition on microglia were analyzed by immunohistochemical stainings and in situ hybridization of retinal sections and flat mounts. Pro-inflammatory cytokine levels in the retina and retinal pigment epithelium (RPE) were quantified by qRT-PCR and transcriptomic changes were analyzed by RNA-sequencing. Retinal thickness and structure were evaluated by optical coherence tomography. Results We found that galectin-3 expression was strongly upregulated in reactive retinal mononuclear phagocytes of AMD patients and in the two related mouse models of light-induced retinal degeneration. The experimental in vivo data further showed that specific targeting of galectin-3 by genetic knockout or administration of the small-molecule inhibitor TD139 reduced microglia reactivity and delayed retinal damage in both light damage conditions. Conclusion This study defines galectin-3 as a potent driver of retinal degeneration and highlights the protein as a drug target for ocular immunomodulatory therapies. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02589-6.
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16
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Tolentino MJ, Tolentino AJ. Investigational drugs in clinical trials for macular degeneration. Expert Opin Investig Drugs 2022; 31:1067-1085. [PMID: 35962560 DOI: 10.1080/13543784.2022.2113375] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Intravitreal anti-vascular endothelial growth factor (VEGF) injections for exudative age-related macular degeneration (eAMD) are effective and safe but require frequent injections and have nonresponding patients. Geographic atrophy/dry AMD (gaAMD) remains an unmet medical need . New therapies are needed to address this leading cause of blindness in the increasing aged population. AREAS COVERED This paper reviews the pathogenesis of macular degeneration, current and failed therapeutics, therapies undergoing clinical trials and a rationale for why certain AMD therapies may succeed or fail . EXPERT OPINION VEGF- inhibitors reduce both vascular leakage and neovascularization. Experimental therapies that only address neovascularization or leakage will unlikely supplant anti-VEGF therapies. The most promising future therapies for eAMD, are those that target, more potently inhibit and have a more sustained effect on the VEGF pathway such as KSI-301, RGX-314, CLS-AX, EYEP-1901, OTX-TKI. GaAMD is a phenotype of phagocytic retinal cell loss. Inhibiting phagocytic activity of retinal microglial/macrophages at the border of GA and reducing complement derived activators of microglial/macrophage is the most promising strategy. Complement inhibitors (Pegcetacoplan and Avacincaptad pegol) will likely obtain FDA approval but will serve to pave the way for combined complement and direct phagocytic inhibitors such as AVD-104.
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Affiliation(s)
- Michael J Tolentino
- University of Central Florida, FL, USA.,Blue Ocean Clinical Research, Lakeland, FL, USA.,Aviceda Therapeutics, Cambridge, MA, USA
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17
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Dhodapkar RM, Martell D, Hafler BP. Glial-mediated neuroinflammatory mechanisms in age-related macular degeneration. Semin Immunopathol 2022; 44:673-683. [PMID: 35513496 DOI: 10.1007/s00281-022-00939-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 04/14/2022] [Indexed: 12/21/2022]
Abstract
Age-related macular degeneration (AMD) is a neurodegenerative disorder characterized by photoreceptor and retinal pigment epithelium loss often complicated by neovascularization and is one of the leading causes of irreversible vision loss worldwide. However, the precise pathophysiology of AMD remains to date unclear, and there is a dearth of effective therapies for the early stages of the disease. A growing body of evidence has identified microglia-mediated neuroinflammation as a key driver of neuronal damage in AMD, presenting a novel avenue for the development of pharmacological agents targeting this cell population. The local microglial response interacts with other glia as well as engages in crosstalk with peripheral immunological niches. This article presents a review of the current evidence regarding the involvement of glia in the pathophysiology of AMD, an overview of the key immune circuits and effector mechanisms shown to be active in AMD, and potential therapeutic avenues targeting glial involvement.
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Affiliation(s)
| | - Diego Martell
- Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, USA
| | - Brian P Hafler
- Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, USA.
- Department of Pathology, Yale University, New Haven, CT, USA.
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18
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Shahraz A, Lin Y, Mbroh J, Winkler J, Liao H, Lackmann M, Bungartz A, Zipfel PF, Skerka C, Neumann H. Low molecular weight polysialic acid binds to properdin and reduces the activity of the alternative complement pathway. Sci Rep 2022; 12:5818. [PMID: 35388026 PMCID: PMC8987038 DOI: 10.1038/s41598-022-09407-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 03/21/2022] [Indexed: 11/09/2022] Open
Abstract
Sialic acids as the terminal caps of the cellular glycocalyx play an essential role in self-recognition and were shown to modulate complement processes via interaction between α2,3-linked sialic acids and complement factor H. Previously, it was suggested that low molecular weight α2,8-linked polysialic acid (polySia avDP20) interferes with complement activation, but the exact molecular mechanism is still unclear. Here, we show that soluble polySia avDP20 (molecular weight of ~ 6 kDa) reduced the binding of serum-derived alternative pathway complement activator properdin to the cell surface of lesioned Hepa-1c1c7 and PC-12 neuroblastoma cells. Furthermore, polySia avDP20 added to human serum blocked the alternative complement pathway triggered by plate-bound lipopolysaccharides. Interestingly, no inhibitory effect was observed with monosialic acid or oligosialic acid with a chain length of DP3 and DP5. In addition, polySia avDP20 directly bound properdin, but not complement factor H. These data show that soluble polySia avDP20 binds properdin and reduces the alternative complement pathway activity. Results strengthen the previously described concept of self-recognition of sialylation as check-point control of complement activation in innate immunity.
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Affiliation(s)
- Anahita Shahraz
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Yuchen Lin
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Joshua Mbroh
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Jonas Winkler
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Huan Liao
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Marie Lackmann
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Annemarie Bungartz
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany.,Infection Biology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Harald Neumann
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
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19
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Transgenic mouse models to study the physiological and pathophysiological roles of human Siglecs. Biochem Soc Trans 2022; 50:935-950. [PMID: 35383825 DOI: 10.1042/bst20211203] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/14/2022] [Accepted: 03/18/2022] [Indexed: 12/14/2022]
Abstract
Sialic acid-binding immunoglobulin-like lectins (Siglecs) are important immunomodulatory receptors. Due to differences between human and mouse Siglecs, defining the in vivo roles for human Siglecs (hSiglecs) can be challenging. One solution is the development and use of hSiglec transgenic mice to assess the physiological roles of hSiglecs in health and disease. These transgenic mice can also serve as important models for the pre-clinical testing of immunomodulatory approaches that are based on targeting hSiglecs. Four general methods have been used to create hSiglec-expressing transgenic mice, each with associated advantages and disadvantages. To date, transgenic mouse models expressing hSiglec-2 (CD22), -3 (CD33), -7, -8, -9, -11, and -16 have been created. This review focuses on both the generation of these hSiglec transgenic mice, along with the important findings that have been made through their study. Cumulatively, hSiglec transgenic mouse models are providing a deeper understanding of the differences between human and mice orthologs/paralogs, mechanisms by which Siglecs regulate immune cell signaling, physiological roles of Siglecs in disease, and different paradigms where targeting Siglecs may be therapeutically advantageous.
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Thiesler H, Küçükerden M, Gretenkort L, Röckle I, Hildebrandt H. News and Views on Polysialic Acid: From Tumor Progression and Brain Development to Psychiatric Disorders, Neurodegeneration, Myelin Repair and Immunomodulation. Front Cell Dev Biol 2022; 10:871757. [PMID: 35617589 PMCID: PMC9013797 DOI: 10.3389/fcell.2022.871757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 03/08/2022] [Indexed: 12/15/2022] Open
Abstract
Polysialic acid (polySia) is a sugar homopolymer consisting of at least eight glycosidically linked sialic acid units. It is a posttranslational modification of a limited number of proteins with the neural cell adhesion molecule NCAM being the most prominent. As extensively reviewed before, polySia-NCAM is crucial for brain development and synaptic plasticity but also modulates tumor growth and malignancy. Functions of polySia have been attributed to its polyanionic character, its spatial expansion into the extracellular space, and its modulation of NCAM interactions. In this mini-review, we first summarize briefly, how the modulation of NCAM functions by polySia impacts tumor cell growth and leads to malformations during brain development of polySia-deficient mice, with a focus on how the latter may be linked to altered behaviors in the mouse model and to neurodevelopmental predispositions to psychiatric disorders. We then elaborate on the implications of polySia functions in hippocampal plasticity, learning and memory of mice in light of recently described polySia changes related to altered neurogenesis in the aging human brain and in neurodegenerative disease. Furthermore, we highlight recent progress that extends the range of polySia functions across diverse fields of neurobiology such as cortical interneuron development and connectivity, myelination and myelin repair, or the regulation of microglia activity. We discuss possible common and distinct mechanisms that may underlie these seemingly divergent roles of polySia, and provide prospects for new therapeutic approaches building on our improved understanding of polySia functions.
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Feng L, Weng J, Yao C, Wang R, Wang N, Zhang Y, Tanaka Y, Su L. Extracellular Vesicles Derived from SIPA1high Breast Cancer Cells Enhance Macrophage Infiltration and Cancer Metastasis through Myosin-9. BIOLOGY 2022; 11:biology11040543. [PMID: 35453742 PMCID: PMC9032110 DOI: 10.3390/biology11040543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 12/24/2022]
Abstract
Simple Summary The high expression of signal-induced proliferation-associated 1 (SIPA1) in breast cancer could aggravate cancer cell metastasis, but how the tumour microenvironment is involved in this incident is unknown. In this study, we investigated whether breast cancer cells with high SIPA1 expression recruited macrophages into the tumour microenvironment. We also found that extracellular vesicles (EVs) derived from MDA-MB-231 cells significantly enhanced macrophage migration, compared with that from SIPA1-knockdown MDA-MB-231 cells both in vitro and in vivo. In terms of the mechanism, SIPA1 in cancer cells modulated the key protein myosin-9 in EVs and promoted macrophage infiltration via EVs. We confirmed that either down-regulating SIPA1 expression or blocking myosin-9 by its inhibitor, blebbistatin, led to the suppression of macrophage infiltration. These findings contribute to a deep understanding of how SIPA1 regulates the tumour microenvironment in breast cancer to facilitate tumour metastasis and provide a basis for the development of therapeutics against breast cancer metastasis. Abstract Tumour cell metastasis can be genetically regulated by proteins contained in cancer cell-derived extracellular vesicles (EVs) released to the tumour microenvironment. Here, we found that the number of infiltrated macrophages was positively correlated with the expression of signal-induced proliferation-associated 1 (SIPA1) in invasive breast ductal carcinoma tissues and MDA-MB-231 xenograft tumours. EVs derived from MDA-MB-231 cells (231-EVs) significantly enhanced macrophage migration, compared with that from SIPA1-knockdown MDA-MB-231 cells (231/si-EVs) both in vitro and in vivo. We revealed that SIPA1 promoted the transcription of MYH9, which encodes myosin-9, and up-regulated the expression level of myosin-9 in breast cancer cells and their EVs. We also found that blocking myosin-9 by either down-regulating SIPA1 expression or blebbistatin treatment led to the suppression of macrophage infiltration. Survival analysis showed that breast cancer patients with high expression of SIPA1 and MYH9 molecules had worse relapse-free survival (p = 0.028). In summary, SIPA1high breast cancer can enhance macrophage infiltration through EVs enriched with myosin-9, which might aggravate the malignancy of breast cancer.
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Affiliation(s)
- Lingyun Feng
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China; (L.F.); (J.W.); (C.Y.); (R.W.); (N.W.)
| | - Jun Weng
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China; (L.F.); (J.W.); (C.Y.); (R.W.); (N.W.)
| | - Chenguang Yao
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China; (L.F.); (J.W.); (C.Y.); (R.W.); (N.W.)
| | - Ruyuan Wang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China; (L.F.); (J.W.); (C.Y.); (R.W.); (N.W.)
| | - Ning Wang
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China; (L.F.); (J.W.); (C.Y.); (R.W.); (N.W.)
| | - Yilei Zhang
- The Institute of Molecular and Translational Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China;
| | - Yoshimasa Tanaka
- Center for Medical Innovation, Nagasaki University, 1-7-1, Sakamoto, Nagasaki 852-8588, Japan
- Correspondence: (Y.T.); (L.S.); Tel.: +81-95-819-7063 (Y.T.); +86-27-8779-2024 (L.S.); Fax: +81-95-819-2189 (Y.T.); +86-27-8779-2072 (L.S.)
| | - Li Su
- Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China; (L.F.); (J.W.); (C.Y.); (R.W.); (N.W.)
- Correspondence: (Y.T.); (L.S.); Tel.: +81-95-819-7063 (Y.T.); +86-27-8779-2024 (L.S.); Fax: +81-95-819-2189 (Y.T.); +86-27-8779-2072 (L.S.)
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22
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Villanueva-Cabello TM, Gutiérrez-Valenzuela LD, Salinas-Marín R, López-Guerrero DV, Martínez-Duncker I. Polysialic Acid in the Immune System. Front Immunol 2022; 12:823637. [PMID: 35222358 PMCID: PMC8873093 DOI: 10.3389/fimmu.2021.823637] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 12/28/2021] [Indexed: 01/01/2023] Open
Abstract
Polysialic acid (polySia) is a highly regulated polymer of sialic acid (Sia) with such potent biophysical characteristics that when expressed drastically influences the interaction properties of cells. Although much of what is known of polySia in mammals has been elucidated from the study of its role in the central nervous system (CNS), polySia is also expressed in other tissues, including the immune system where it presents dynamic changes during differentiation, maturation, and activation of different types of immune cells of the innate and adaptive response, being involved in key regulatory mechanisms. At least six polySia protein carriers (CCR7, ESL-1, NCAM, NRP2, ST8Sia 2, and ST8Sia 4) are expressed in different types of immune cells, but there is still much to be explored in regard not only to the regulatory mechanisms that determine their expression and the structure of polySia chains but also to the identification of the cis- and trans- ligands of polySia that establish signaling networks. This review summarizes the current knowledge on polySia in the immune system, addressing its biosynthesis, its tools for identification and structural characterization, and its functional roles and therapeutic implications.
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Affiliation(s)
- Tania M. Villanueva-Cabello
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Lya D. Gutiérrez-Valenzuela
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Roberta Salinas-Marín
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | | | - Iván Martínez-Duncker
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
- *Correspondence: Iván Martínez-Duncker,
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O-Acetylation of Capsular Polysialic Acid Enables Escherichia coli K1 Escaping from Siglec-Mediated Innate Immunity and Lysosomal Degradation of E. coli-Containing Vacuoles in Macrophage-Like Cells. Microbiol Spectr 2021; 9:e0039921. [PMID: 34878295 PMCID: PMC8653822 DOI: 10.1128/spectrum.00399-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli K1 causes bacteremia and meningitis in human neonates. The K1 capsule, an α2,8-linked polysialic acid (PSA) homopolymer, is its essential virulence factor. PSA is usually partially modified by O-acetyl groups. It is known that O-acetylation alters the antigenicity of PSA, but its impact on the interactions between E. coli K1 and host cells is unclear. In this study, a phase variant was obtained by passage of E. coli K1 parent strain, which expressed a capsule with 44% O-acetylation whereas the capsule of the parent strain has only 3%. The variant strain showed significantly reduced adherence and invasion to macrophage-like cells in comparison to the parent strain. Furthermore, we found that O-acetylation of PSA enhanced the modulation of trafficking of E. coli-containing vacuoles (ECV), enabling them to avoid fusing with lysosomes in these cells. Intriguingly, by using quartz crystal microbalance, we demonstrated that the PSA purified from the parent strain interacted with human sialic acid-binding immunoglobulin-like lectins (Siglecs), including Siglec-5, Siglec-7, Siglec-11, and Siglec-14. However, O-acetylated PSA from the variant interacted much less and also suppressed the production of Siglec-mediated proinflammatory cytokines. The adherence of the parent strain to human macrophage-like cells was significantly blocked by monoclonal antibodies against Siglec-11 and Siglec-14. Furthermore, the variant strain caused increased bacteremia and higher lethality in neonatal mice compared to the parent strain. These data elucidate that O-acetylation of K1 capsule enables E. coli to escape from Siglec-mediated innate immunity and lysosomal degradation; therefore, it is a strategy used by E. coli K1 to regulate its virulence. IMPORTANCEEscherichia coli K1 is a leading cause of neonatal meningitis. The mortality and morbidity of this disease remain significantly high despite antibiotic therapy. One major limitation on advances in prevention and therapy for meningitis is an incomplete understanding of its pathogenesis. E. coli K1 is surrounded by PSA, which is observed to have high-frequency variation of O-acetyl modification. Here, we present an in-depth study of the function of O-acetylation in PSA at each stage of host-pathogen interaction. We found that a high level of O-acetylation significantly interfered with Siglec-mediated bacterial adherence to macrophage-like cells, and blunted the proinflammatory response. Furthermore, the O-acetylation of PSA modulated the trafficking of ECVs to prevent them from fusing with lysosomes, enabling them to escape degradation by lysozymes within these cells. Elucidating how subtle modification of the capsule enhances bacterial defenses against host innate immunity will enable the future development of effective drugs or vaccines against infection by E. coli K1.
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Karmakar J, Mukherjee K, Mandal C. Siglecs Modulate Activities of Immune Cells Through Positive and Negative Regulation of ROS Generation. Front Immunol 2021; 12:758588. [PMID: 34804046 PMCID: PMC8595208 DOI: 10.3389/fimmu.2021.758588] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 10/18/2021] [Indexed: 12/13/2022] Open
Abstract
Reactive oxygen species (ROS) are a group of oxygen-containing highly-reactive molecules produced from oxidative metabolic processes or in response to intracellular signals like cytokines and external stimuli like pathogen attack. They regulate a range of physiological processes and are involved in innate immune responses against infectious agents. Deregulation of ROS contributes to a plethora of disease conditions. Sialic acids are carbohydrates, present on cell surfaces or soluble proteins. Sialic acid-binding immunoglobulin-like lectins (Siglecs) recognize and bind to sialic acids. These are widely expressed on various types of immune cells. Siglecs modulate immune activation and can promote or inhibit ROS generation under different contexts. Siglecs promote ROS-dependent cell death in neutrophils and eosinophils while limiting oxidative stress associated with chronic obstructive pulmonary disease (COPD), sickle cell disease (SCD), coronavirus disease-2019 (COVID-19), etc. This review distinguishes itself in summarizing the current understanding of the role of Siglecs in moderating ROS production and their distinct effect on different immune cells; that ultimately determine the cellular response and the disease outcome. This is an important field of investigation having scope for both expansion and medical importance.
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Affiliation(s)
| | | | - Chitra Mandal
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Biology, Kolkata, India
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25
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Jarahian M, Marofi F, Maashi MS, Ghaebi M, Khezri A, Berger MR. Re-Expression of Poly/Oligo-Sialylated Adhesion Molecules on the Surface of Tumor Cells Disrupts Their Interaction with Immune-Effector Cells and Contributes to Pathophysiological Immune Escape. Cancers (Basel) 2021; 13:5203. [PMID: 34680351 PMCID: PMC8534074 DOI: 10.3390/cancers13205203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 12/28/2022] Open
Abstract
Glycans linked to surface proteins are the most complex biological macromolecules that play an active role in various cellular mechanisms. This diversity is the basis of cell-cell interaction and communication, cell growth, cell migration, as well as co-stimulatory or inhibitory signaling. Our review describes the importance of neuraminic acid and its derivatives as recognition elements, which are located at the outermost positions of carbohydrate chains linked to specific glycoproteins or glycolipids. Tumor cells, especially from solid tumors, mask themselves by re-expression of hypersialylated neural cell adhesion molecule (NCAM), neuropilin-2 (NRP-2), or synaptic cell adhesion molecule 1 (SynCAM 1) in order to protect themselves against the cytotoxic attack of the also highly sialylated immune effector cells. More particularly, we focus on α-2,8-linked polysialic acid chains, which characterize carrier glycoproteins such as NCAM, NRP-2, or SynCam-1. This characteristic property correlates with an aggressive clinical phenotype and endows them with multiple roles in biological processes that underlie all steps of cancer progression, including regulation of cell-cell and/or cell-extracellular matrix interactions, as well as increased proliferation, migration, reduced apoptosis rate of tumor cells, angiogenesis, and metastasis. Specifically, re-expression of poly/oligo-sialylated adhesion molecules on the surface of tumor cells disrupts their interaction with immune-effector cells and contributes to pathophysiological immune escape. Further, sialylated glycoproteins induce immunoregulatory cytokines and growth factors through interactions with sialic acid-binding immunoglobulin-like lectins. We describe the processes, which modulate the interaction between sialylated carrier glycoproteins and their ligands, and illustrate that sialic acids could be targets of novel therapeutic strategies for treatment of cancer and immune diseases.
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Affiliation(s)
- Mostafa Jarahian
- German Cancer Research Center, Toxicology and Chemotherapy Unit Heidelberg, 69120 Heidelberg, Germany;
| | - Faroogh Marofi
- Department of Hematology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz 5165665931, Iran;
| | - Marwah Suliman Maashi
- Stem Cells and Regenerative Medicine Unit at King Fahad Medical Research Centre, Jeddah 11211, Saudi Arabia;
| | - Mahnaz Ghaebi
- Cancer Gene Therapy Research Center (CGRC), Zanjan University of Medical Sciences, Zanjan 4513956184, Iran;
| | - Abdolrahman Khezri
- Department of Biotechnology, Inland Norway University of Applied Sciences, 2418 Hamar, Norway;
| | - Martin R. Berger
- German Cancer Research Center, Toxicology and Chemotherapy Unit Heidelberg, 69120 Heidelberg, Germany;
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26
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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: 4] [Impact Index Per Article: 1.3] [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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27
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Liao H, Winkler J, Wißfeld J, Shahraz A, Klaus C, Neumann H. Low molecular weight polysialic acid prevents lipopolysaccharide-induced inflammatory dopaminergic neurodegeneration in humanized SIGLEC11 transgenic mice. Glia 2021; 69:2845-2862. [PMID: 34406679 DOI: 10.1002/glia.24073] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 01/28/2023]
Abstract
Parkinson's disease is one of the most common neurodegenerative diseases in the elderly population, with a pathophysiology linked to neuroinflammation, complement activation, and oxidative damage. Soluble polysialic acid with an average degree of polymerization 20 (polySia avDP20) prevents inflammation and oxidative burst in human macrophages via sialic acid-binding immunoglobulin like lectin-11 (SIGLEC11) receptor and interferes with alternative complement activation. Here, we confirmed the anti-inflammatory capacity of polySia avDP20 on cultured murine embryonic stem cell-derived microglia and analyzed the effect of polySia avDP20 in a lipopolysaccharide-triggered animal model of Parkinson's disease. We demonstrated a neuroprotective effect of intraperitoneally applied polySia avDP20 in humanized SIGLEC11 transgenic mice after repeated systemic challenge with lipopolysaccharide. Pathway enrichment analysis of the brain transcriptome on day 19 after disease initiation showed that intraperitoneal application of 10 μg/g body weight polySia avDP20 prevented excessive inflammation. In line with these data, polySia avDP20 attenuated the lipopolysaccharide-triggered increase in mRNA levels of immune-related genes (Il1b, Cd14, Myd88, Fcer1g, Itgam, C4, Cybb, Iba1 and Cd68) and cell death-related genes (Casp8, Ripk1 and Ripk3) in the brains of SIGLEC11 transgenic mice on day 19, but not on day 5. Moreover, immunohistochemistry demonstrated that polySia avDP20 reduced the lipopolysaccharide-induced increase in immunoreactivity of IBA1 and CD68 in the substantia nigra pars reticulata in SIGLEC11 transgenic and wild type mice on day 19. Furthermore, treatment with polySia avDP20 prevented the loss of dopaminergic neurons in the substantia nigra pars compacta induced by lipopolysaccharide challenge in both SIGLEC11 transgenic and wild type mice on day 19. Thus, our data demonstrate that polySia avDP20 ameliorates inflammatory dopaminergic neurodegeneration and therefore is a promising drug candidate to prevent Parkinson's disease-related inflammation and neurodegeneration.
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Affiliation(s)
- Huan Liao
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Jonas Winkler
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Jannis Wißfeld
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Anahita Shahraz
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Christine Klaus
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Harald Neumann
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
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Wielgat P, Niemirowicz-Laskowska K, Wilczewska AZ, Car H. Sialic Acid-Modified Nanoparticles-New Approaches in the Glioma Management-Perspective Review. Int J Mol Sci 2021; 22:ijms22147494. [PMID: 34299113 PMCID: PMC8304714 DOI: 10.3390/ijms22147494] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/02/2021] [Accepted: 07/10/2021] [Indexed: 12/23/2022] Open
Abstract
The cell surface is covered by a dense and complex network of glycans attached to the membrane proteins and lipids. In gliomas, the aberrant sialylation, as the final stage of glycosylation, is an important regulatory mechanism of malignant cell behavior and correlates with worse prognosis. Better understanding of the role of sialylation in cellular and molecular processes opens a new way in the development of therapeutic tools for human brain tumors. According to the recent clinical observation, the cellular heterogeneity, activity of brain cancer stem cells (BCSCs), immune evasion, and function of the blood–brain barrier (BBB) are attractive targets for new therapeutic strategies. In this review, we summarize the importance of sialic acid-modified nanoparticles in brain tumor progression.
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Affiliation(s)
- Przemyslaw Wielgat
- Department of Clinical Pharmacology, Medical University of Bialystok, Waszyngtona 15A, 15-274 Bialystok, Poland;
- Correspondence: (P.W.); (K.N.-L.); Tel.: +48-85-7450647 (P.W.); +48-85-7485554 (K.N.-L.)
| | - Katarzyna Niemirowicz-Laskowska
- Department of Experimental Pharmacology, Medical University of Bialystok, Szpitalna 37, 15-265 Bialystok, Poland
- Correspondence: (P.W.); (K.N.-L.); Tel.: +48-85-7450647 (P.W.); +48-85-7485554 (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, 15-265 Bialystok, Poland
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29
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Mindler K, Ostertag E, Stehle T. The polyfunctional polysialic acid: A structural view. Carbohydr Res 2021; 507:108376. [PMID: 34273862 DOI: 10.1016/j.carres.2021.108376] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/09/2021] [Accepted: 06/09/2021] [Indexed: 12/15/2022]
Abstract
Polysialic acid (polySia), a homopolymer of α2,8-linked sialic acid residues, modifies a small number of proteins and has central functions in vertebrate signalling. Here, we review the regulatory functions of polySia in signalling processes and the immune system of adult humans, as well as functions based on their chemical properties. The main focus will be on the structure-function relationship of polySia with its interaction partners in humans. Recent studies have indicated that the degree of polymerisation is an important parameter that can guide the regulatory effect of polySia in addition to its binding to target proteins. Therefore, the structures of polySia in solution and bound to interaction partners are compared in order to identify the key factors that define binding specificity.
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Affiliation(s)
- Katja Mindler
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076, Tübingen, Germany
| | - Elena Ostertag
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076, Tübingen, Germany
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tübingen, 72076, Tübingen, Germany.
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30
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Sarver AL, Xie C, Riddle MJ, Forster CL, Wang X, Lu H, Wagner W, Tolar J, Hallstrom TC. Retinoblastoma tumor cell proliferation is negatively associated with an immune gene expression signature and increased immune cells. J Transl Med 2021; 101:701-718. [PMID: 33658609 DOI: 10.1038/s41374-021-00573-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 12/30/2022] Open
Abstract
This study focuses on gene expression differences between early retinal states that ultimately lead to normal development, late onset retinoblastoma, or rapid bilateral retinoblastoma tumors. The late-onset and early-onset retinoblastoma tumor cells are remarkably similar to normally proliferating retinal progenitor cells, but they fail to properly express differentiation markers associated with normal development. Further, early-onset retinoblastoma tumor cells express a robust immune gene expression signature followed by accumulation of dendritic, monocyte, macrophage, and T-lymphocyte cells in the retinoblastoma tumors. This characteristic was not shared by either normal retinae or late-onset retinoblastomas. Comparison of our data with other human and mouse retinoblastoma tumor gene expression significantly confirmed, that the immune signature is present in tumors from each species. Strikingly, we observed that the immune signature in both mouse and human tumors was most highly evident in those with the lowest proliferative capacity. We directly assessed this relationship in human retinoblastoma tumors by co-analyzing proliferation and immune cell recruitment by immunohistochemistry, uncovering a significant inverse relationship between increased immune-cell infiltration in tumors and reduced tumor cell proliferation. Directly inhibiting proliferation with a PI3K/mTOR inhibitor significantly increased the number of CD45+ immune cells in the retina. This work establishes an in vivo model for the rapid recruitment of immune cells to tumorigenic neural tissue.
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Affiliation(s)
- Aaron L Sarver
- Institute for Health Informatics, Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Chencheng Xie
- Department of Pediatrics, Division of Blood and Marrow Transplantation, University of Minnesota, Minneapolis, MN, USA
| | - Megan J Riddle
- Department of Pediatrics, Division of Blood and Marrow Transplantation, University of Minnesota, Minneapolis, MN, USA
| | - Colleen L Forster
- BioNet, Academic Health Center, University of Minnesota, Minneapolis, MN, USA
| | - Xiaohong Wang
- Department of Pediatrics, Division of Blood and Marrow Transplantation, University of Minnesota, Minneapolis, MN, USA
| | - Huarui Lu
- Department of Pediatrics, Division of Blood and Marrow Transplantation, University of Minnesota, Minneapolis, MN, USA
| | - Wyatt Wagner
- Department of Pediatrics, Division of Blood and Marrow Transplantation, University of Minnesota, Minneapolis, MN, USA
| | - Jakub Tolar
- Department of Pediatrics, Division of Blood and Marrow Transplantation, University of Minnesota, Minneapolis, MN, USA
| | - Timothy C Hallstrom
- Department of Pediatrics, Division of Blood and Marrow Transplantation, University of Minnesota, Minneapolis, MN, USA.
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31
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Smith BAH, Bertozzi CR. The clinical impact of glycobiology: targeting selectins, Siglecs and mammalian glycans. Nat Rev Drug Discov 2021; 20:217-243. [PMID: 33462432 PMCID: PMC7812346 DOI: 10.1038/s41573-020-00093-1] [Citation(s) in RCA: 198] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2020] [Indexed: 01/31/2023]
Abstract
Carbohydrates - namely glycans - decorate every cell in the human body and most secreted proteins. Advances in genomics, glycoproteomics and tools from chemical biology have made glycobiology more tractable and understandable. Dysregulated glycosylation plays a major role in disease processes from immune evasion to cognition, sparking research that aims to target glycans for therapeutic benefit. The field is now poised for a boom in drug development. As a harbinger of this activity, glycobiology has already produced several drugs that have improved human health or are currently being translated to the clinic. Focusing on three areas - selectins, Siglecs and glycan-targeted antibodies - this Review aims to tell the stories behind therapies inspired by glycans and to outline how the lessons learned from these approaches are paving the way for future glycobiology-focused therapeutics.
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Affiliation(s)
- Benjamin A H Smith
- Department of Chemical & Systems Biology and ChEM-H, Stanford School of Medicine, Stanford, CA, USA
| | - Carolyn R Bertozzi
- Department of Chemical & Systems Biology and ChEM-H, Stanford School of Medicine, Stanford, CA, USA.
- Department of Chemistry, Stanford University, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
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Delaveris CS, Chiu SH, Riley NM, Bertozzi CR. Modulation of immune cell reactivity with cis-binding Siglec agonists. Proc Natl Acad Sci U S A 2021; 118:e2012408118. [PMID: 33431669 PMCID: PMC7826350 DOI: 10.1073/pnas.2012408118] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Inflammatory pathologies caused by phagocytes lead to numerous debilitating conditions, including chronic pain and blindness due to age-related macular degeneration. Many members of the sialic acid-binding immunoglobulin-like lectin (Siglec) family are immunoinhibitory receptors whose agonism is an attractive approach for antiinflammatory therapy. Here, we show that synthetic lipid-conjugated glycopolypeptides can insert into cell membranes and engage Siglec receptors in cis, leading to inhibitory signaling. Specifically, we construct a cis-binding agonist of Siglec-9 and show that it modulates mitogen-activated protein kinase (MAPK) signaling in reporter cell lines, immortalized macrophage and microglial cell lines, and primary human macrophages. Thus, these cis-binding agonists of Siglecs present a method for therapeutic suppression of immune cell reactivity.
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Affiliation(s)
- Corleone S Delaveris
- Department of Chemistry, Stanford University, Stanford, CA 94305
- Stanford ChEM-H, Stanford University, Stanford, CA 94305
| | - Shannon H Chiu
- Department of Chemistry, Stanford University, Stanford, CA 94305
- Stanford ChEM-H, Stanford University, Stanford, CA 94305
| | - Nicholas M Riley
- Department of Chemistry, Stanford University, Stanford, CA 94305
| | - Carolyn R Bertozzi
- Department of Chemistry, Stanford University, Stanford, CA 94305;
- Stanford ChEM-H, Stanford University, Stanford, CA 94305
- HHMI, Stanford University, Stanford, CA 94305
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33
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Klaus C, Liao H, Allendorf DH, Brown GC, Neumann H. Sialylation acts as a checkpoint for innate immune responses in the central nervous system. Glia 2020; 69:1619-1636. [PMID: 33340149 DOI: 10.1002/glia.23945] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 12/28/2022]
Abstract
Sialic acids are monosaccharides that normally terminate the glycan chains of cell surface glyco-proteins and -lipids in mammals, and are highly enriched in the central nervous tissue. Sialic acids are conjugated to proteins and lipids (termed "sialylation") by specific sialyltransferases, and are removed ("desialylation") by neuraminidases. Cell surface sialic acids are sensed by complement factor H (FH) to inhibit complement activation or by sialic acid-binding immunoglobulin-like lectin (SIGLEC) receptors to inhibit microglial activation, phagocytosis, and oxidative burst. In contrast, desialylation of cells enables binding of the opsonins C1, calreticulin, galectin-3, and collectins, stimulating phagocytosis of such cells. Hypersialylation is used by bacteria and cancers as camouflage to escape immune recognition, while polysialylation of neurons protects synapses and neurogenesis. Insufficient lysosomal cleavage of sialylated molecules can lead to lysosomal accumulation of lipids and aggregated proteins, which if excessive may be expelled into the extracellular space. On the other hand, desialylation of immune receptors can activate them or trigger removal of proteins. Loss of inhibitory SIGLECs or FH triggers reduced clearance of aggregates, oxidative brain damage and complement-mediated retinal damage. Thus, cell surface sialylation recognized by FH, SIGLEC, and other immune-related receptors acts as a major checkpoint inhibitor of innate immune responses in the central nervous system, while excessive cleavage of sialic acid residues and consequently removing this checkpoint inhibitor may trigger lipid accumulation, protein aggregation, inflammation, and neurodegeneration.
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Affiliation(s)
- Christine Klaus
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Huan Liao
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | | | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
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Bartling B, Brüchle NC, Rehfeld JS, Boßmann D, Fiebig T, Litschko C, Fohrer J, Gerardy-Schahn R, Scheper T, Beutel S. Accelerated production of α2,8- and α2,9-linked polysialic acid in recombinant Escherichia coli using high cell density cultivation. BIOTECHNOLOGY REPORTS (AMSTERDAM, NETHERLANDS) 2020; 28:e00562. [PMID: 33304838 PMCID: PMC7711218 DOI: 10.1016/j.btre.2020.e00562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/05/2020] [Accepted: 11/17/2020] [Indexed: 11/29/2022]
Abstract
Polysialic acid (polySia) are α2,8- and/or α2,9-linked homopolymers with interesting properties for meningococcal vaccine development or the cure of human neurodegenerative disorders. With the goal to avoid large scale production of pathogenic bacteria, we compare in the current study the efficacy of conventional polySia production to recombinant approaches using the engineered laboratory safety strain E. coli BL21. High cell density cultivation (HCDC) experiments were performed in two different bioreactor systems. Increased cell densities of up to 11.3 (±0.4) g/L and polySia concentrations of up to 774 (±18) mg/L were reached in E. coli K1. However, cultivation of engineered E. coli BL21 strains delivered comparable cell densities but a maximum of only 133 mg/L polySia. Using established downstream procedures, host cell DNA and proteins were removed. All recombinant polySia products showed an identical degree of polymerization >90. Polymers with different glycosidic linkages could be successfully differentiated by nuclear magnetic resonance spectroscopy.
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Affiliation(s)
- Bastian Bartling
- Institute of Technical Chemistry, Leibniz University Hannover, D-30167 Hannover, Germany
| | - Nora C. Brüchle
- Institute of Technical Chemistry, Leibniz University Hannover, D-30167 Hannover, Germany
| | - Johanna S. Rehfeld
- Institute of Technical Chemistry, Leibniz University Hannover, D-30167 Hannover, Germany
| | - Daniel Boßmann
- Institute of Technical Chemistry, Leibniz University Hannover, D-30167 Hannover, Germany
| | - Timm Fiebig
- Institute of Clinical Biochemistry, Hannover Medical School, D-30625 Hannover, Germany
| | - Christa Litschko
- Institute of Clinical Biochemistry, Hannover Medical School, D-30625 Hannover, Germany
| | - Jörg Fohrer
- Institute of Organic Chemistry, Leibniz University Hannover, D-30167 Hannover, Germany
| | - Rita Gerardy-Schahn
- Institute of Clinical Biochemistry, Hannover Medical School, D-30625 Hannover, Germany
| | - Thomas Scheper
- Institute of Technical Chemistry, Leibniz University Hannover, D-30167 Hannover, Germany
| | - Sascha Beutel
- Institute of Technical Chemistry, Leibniz University Hannover, D-30167 Hannover, Germany
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35
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Läubli H, Kawanishi K, George Vazhappilly C, Matar R, Merheb M, Sarwar Siddiqui S. Tools to study and target the Siglec-sialic acid axis in cancer. FEBS J 2020; 288:6206-6225. [PMID: 33251699 DOI: 10.1111/febs.15647] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/18/2020] [Accepted: 11/23/2020] [Indexed: 12/16/2022]
Abstract
Siglecs are widely expressed on leucocytes and bind to ubiquitously presented glycans containing sialic acids (sialoglycans). Most Siglecs carry an immunoreceptor tyrosine-based inhibition motif (ITIM) and elicit an inhibitory intracellular signal upon ligand binding. A few Siglec receptors can, however, recruit immunoreceptor tyrosine-based activation motif (ITAM)-containing factors, which activate cells. The role of hypersialylation (the enhanced expression of sialoglycans) has recently been explored in cancer progression. Mechanistic studies have shown that hypersialylation on cancer cells can engage inhibitory Siglecs on the surface of immune cells and induce immunosuppression. These recent studies strongly suggest that the Siglec-sialic acid axis can act as a potential target for cancer immunotherapy. Moreover, the use of new tools and techniques is facilitating these studies. In this review, we summarise techniques used to study Siglecs, including different mouse models, monoclonal antibodies, Siglec fusion proteins, and sialoglycan arrays. Furthermore, we discuss the recent major developments in the study of Siglecs in cancer immunosuppression, tools, and techniques used in targeting the Siglec-sialic acid axis and the possibility of clinical intervention.
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Affiliation(s)
- Heinz Läubli
- Laboratory for Cancer Immunotherapy, Department of Biomedicine, and Medical Oncology, Department of Internal Medicine, University Hospital Basel, Switzerland
| | - Kunio Kawanishi
- Kidney and Vascular Pathology, University of Tsukuba, Ibaraki, Japan
| | | | - Rachel Matar
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), UAE
| | - Maxime Merheb
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), UAE
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36
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Polysialylation and disease. Mol Aspects Med 2020; 79:100892. [PMID: 32863045 DOI: 10.1016/j.mam.2020.100892] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 12/31/2022]
Abstract
Polysialic acid (polySia, PSA) is a unique constituent of the glycocalyx on the surface of bacterial and vertebrate cells. In vertebrates, its biosynthesis is highly regulated, not only in quantity and quality, but also in time and location, which allows polySia to be involved in various important biological phenomena. Therefore, impairments in the expression and structure of polySia sometimes relate to diseases, such as schizophrenia, bipolar disorder, and cancer. Some bacteria express polySia as a tool for protecting themselves from the host immune system during invasion. PolySia is proven to be a biosafe material; polySia, as well as polySia-recognizing molecules, are key therapeutic agents. This review first comprehensive outlines the occurrence, features, biosynthesis, and functions of polySia and subsequently focuses on the related diseases.
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37
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Hane M, Chen DY, Varki A. Human-specific microglial Siglec-11 transcript variant has the potential to affect polysialic acid-mediated brain functions at a distance. Glycobiology 2020; 31:231-242. [PMID: 32845322 DOI: 10.1093/glycob/cwaa082] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/05/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022] Open
Abstract
CD33-related Siglecs are often found on innate immune cells and modulate their reactivity by recognition of sialic acid-based "self-associated molecular patterns" and signaling via intracellular tyrosine-based cytosolic motifs. Previous studies have shown that Siglec-11 specifically binds to the brain-enriched polysialic acid (polySia/PSA) and that its microglial expression in the brain is unique to humans. Furthermore, human microglial Siglec-11 exists as an alternate splice form missing the exon encoding the last (fifth) Ig-like C2-set domain of the extracellular portion of the protein, but little is known about the functional consequences of this variation. Here, we report that the recombinant soluble human microglial form of Siglec-11 (hSiglec-11(4D)-Fc) binds endogenous and immobilized polySia better than the tissue macrophage form (hSiglec-11(5D)-Fc) or the chimpanzee form (cSiglec-11(5D)-Fc). The Siglec-11 protein is also prone to aggregation, potentially influencing its ligand-binding ability. Additionally, Siglec-11 protein can be secreted in both intact and proteolytically cleaved forms. The microglial splice variant has reduced proteolytic release and enhanced incorporation into exosomes, a process that appears to be regulated by palmitoylation of cysteines in the cytosolic tail. Taken together, these data demonstrate that human brain specific microglial hSiglec-11(4D) has different molecular properties and can be released on exosomes and/or as proteolytic products, with the potential to affect polySia-mediated brain functions at a distance.
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Affiliation(s)
- Masaya Hane
- Departments of Medicine and Cellular & Molecular Medicine, Center for Academic Research and Training in Anthropogeny, Glycobiology Research and Training Center, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Dillon Y Chen
- Departments of Medicine and Cellular & Molecular Medicine, Center for Academic Research and Training in Anthropogeny, Glycobiology Research and Training Center, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Ajit Varki
- Departments of Medicine and Cellular & Molecular Medicine, Center for Academic Research and Training in Anthropogeny, Glycobiology Research and Training Center, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
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38
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Liao H, Klaus C, Neumann H. Control of Innate Immunity by Sialic Acids in the Nervous Tissue. Int J Mol Sci 2020; 21:ijms21155494. [PMID: 32752058 PMCID: PMC7432451 DOI: 10.3390/ijms21155494] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/11/2022] Open
Abstract
Sialic acids (Sias) are the most abundant terminal sugar residues of glycoproteins and glycolipids on the surface of mammalian cells. The nervous tissue is the organ with the highest expression level of Sias. The ‘sialylation’ of glycoconjugates is performed via sialyltransferases, whereas ‘desialylation’ is done by sialidases or is a possible consequence of oxidative damage. Sialic acid residues on the neural cell surfaces inhibit complement and microglial activation, as well as phagocytosis of the underlying structures, via binding to (i) complement factor H (CFH) or (ii) sialic acid-binding immunoglobulin-like lectin (SIGLEC) receptors. In contrast, activated microglial cells show sialidase activity that desialylates both microglia and neurons, and further stimulates innate immunity via microglia and complement activation. The desialylation conveys neurons to become susceptible to phagocytosis, as well as triggers a microglial phagocytosis-associated oxidative burst and inflammation. Dysfunctions of the ‘Sia–SIGLEC’ and/or ‘Sia–complement’ axes often lead to neurological diseases. Thus, Sias on glycoconjugates of the intact glycocalyx and its desialylation are major regulators of neuroinflammation.
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Affiliation(s)
| | | | - Harald Neumann
- Correspondence: ; Tel.: +49-228-6885-500; Fax: +49-228-6885-501
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39
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Polysialic acid and Siglec-E orchestrate negative feedback regulation of microglia activation. Cell Mol Life Sci 2020; 78:1637-1653. [PMID: 32725371 PMCID: PMC7904730 DOI: 10.1007/s00018-020-03601-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 06/23/2020] [Accepted: 07/17/2020] [Indexed: 11/09/2022]
Abstract
Polysialic acid (polySia) emerges as a novel regulator of microglia activity. We recently identified polysialylated proteins in the Golgi compartment of murine microglia that are released in response to inflammatory stimulation. Since exogenously added polySia is able to attenuate the inflammatory response, we proposed that the release of polysialylated proteins constitutes a mechanism for negative feedback regulation of microglia activation. Here, we demonstrate that translocation of polySia from the Golgi to the cell surface can be induced by calcium depletion of the Golgi compartment and that polysialylated proteins are continuously released for at least 24 h after the onset of inflammatory stimulation. The latter was unexpected, because polySia signals detected by immunocytochemistry are rapidly depleted. However, it indicates that the amount of released polySia is much higher than anticipated based on immunostaining. This may be crucial for microglial responses during traumatic brain injury (TBI), as we detected polySia signals in activated microglia around a stab wound in the adult mouse brain. In BV2 microglia, the putative polySia receptor Siglec-E is internalized during lipopolysaccharide (LPS)-induced activation and in response to polySia exposure, indicating interaction. Correspondingly, CRISPR/Cas9-mediated Siglec-E knockout prevents inhibition of pro inflammatory activation by exogenously added polySia and leads to a strong increase of the LPS response. A comparable increase of LPS-induced activation has been observed in microglia with abolished polySia synthesis. Together, these results indicate that the release of the microglia-intrinsic polySia pool, as implicated in TBI, inhibits the inflammatory response by acting as a trans-activating ligand of Siglec-E.
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40
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Zhang R, Zhang X, Hu F, Wu J. Fine structure of the human retina defined by confocal microscopic immunohistochemistry. Br J Biomed Sci 2020; 78:28-34. [PMID: 32498649 DOI: 10.1080/09674845.2020.1776586] [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] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Research in to the pathophysiology of the complex layers of retinal and sub-retinal cells is hampered by inadequate recognition of particular cells and tissues. A comprehensive panel of antibodies recognising retinal tissues is lacking. Our purpose was to determine the value of a panel of antibodies labelling various cells in the human retina. METHOD Five groups of antibodies labelled frozen sections of retinas: (1) protein kinase C-α, Glutamine Synthetase (GS) and ionized calcium-binding adapter molecule 1 (Iba1); (2) Parvalbumin, Calretinin and glial fibrillary acidic protein (GFAP); (3) Thy1, GS and Iba1; (4) Rhodopsin, GS and Iba1; and (5) Brn3a, Rhodopsin and protein kinase C-α. The distribution of these antigens were determined by confocal microscopy and calculated grey value of each antibody in each layer of the retina by Image J. RESULTS Different antibodies determined certain retinal layers. Thy 1 is a good determinant of the ganglion cell layer, whilst GS is present in all layers except the photoreceptor layer. Brn3a is specific for the ganglion cell layer whilst parvalbumin marks the ganglion cell layer and the outer plexiform layer. Rhodopsin strongly marks the photoreceptor layer, but this is also marked weakly by GFAP. CONCLUSION The multiple labelling of human retinal cells brings further understanding of the biological characteristics and functions of these cells, and provides a theoretical basis for their possible role in diseases. In the growing field of human retina research, our data may provide a point of reference for future studies of the human retina.
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Affiliation(s)
- R Zhang
- Eye & ENT Hospital, College of Medicine, Fudan University , Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University , Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences , Shanghai, China
| | - X Zhang
- Eye & ENT Hospital, College of Medicine, Fudan University , Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University , Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences , Shanghai, China
| | - F Hu
- Eye & ENT Hospital, College of Medicine, Fudan University , Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University , Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences , Shanghai, China
| | - J Wu
- Eye & ENT Hospital, College of Medicine, Fudan University , Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University , Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Laboratory of Myopia, Chinese Academy of Medical Sciences , Shanghai, China
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41
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Tajik A, Phillips KL, Nitz M, Willis LM. A new ELISA assay demonstrates sex differences in the concentration of serum polysialic acid. Anal Biochem 2020; 600:113743. [DOI: 10.1016/j.ab.2020.113743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/01/2020] [Accepted: 04/14/2020] [Indexed: 12/20/2022]
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42
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Alves CH, Fernandes R, Santiago AR, Ambrósio AF. Microglia Contribution to the Regulation of the Retinal and Choroidal Vasculature in Age-Related Macular Degeneration. Cells 2020; 9:cells9051217. [PMID: 32423062 PMCID: PMC7290930 DOI: 10.3390/cells9051217] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 12/17/2022] Open
Abstract
The retina is a highly metabolically active tissue with high-level consumption of nutrients and oxygen. This high metabolic demand requires a properly developed and maintained vascular system. The retina is nourished by two systems: the central retinal artery that supplies the inner retina and the choriocapillaris that supplies the outer retina and retinal pigment epithelium (RPE). Pathological neovascularization, characterized by endothelial cell proliferation and new vessel formation, is a common hallmark in several retinal degenerative diseases, including age-related macular degeneration (AMD). A limited number of studies have suggested that microglia, the resident immune cells of the retina, have an important role not only in the pathology but also in the formation and physiology of the retinal vascular system. Here, we review the current knowledge on microglial interaction with the retinal vascular system under physiological and pathological conditions. To do so, we first highlight the role of microglial cells in the formation and maintenance of the retinal vasculature system. Thereafter, we discuss the molecular signaling mechanisms through which microglial cells contribute to the alterations in retinal and choroidal vasculatures and to the neovascularization in AMD.
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Affiliation(s)
- C. Henrique Alves
- Retinal Dysfunction and Neuroinflammation Lab, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (C.H.A.); (R.F.); (A.R.S.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-531 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - Rosa Fernandes
- Retinal Dysfunction and Neuroinflammation Lab, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (C.H.A.); (R.F.); (A.R.S.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-531 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - Ana Raquel Santiago
- Retinal Dysfunction and Neuroinflammation Lab, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (C.H.A.); (R.F.); (A.R.S.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-531 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - António Francisco Ambrósio
- Retinal Dysfunction and Neuroinflammation Lab, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (C.H.A.); (R.F.); (A.R.S.)
- Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3004-531 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), 3000-548 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3004-561 Coimbra, Portugal
- Correspondence: ; Tel.: +351-239-480093
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Kiel C, Berber P, Karlstetter M, Aslanidis A, Strunz T, Langmann T, Grassmann F, Weber BH. A Circulating MicroRNA Profile in a Laser-Induced Mouse Model of Choroidal Neovascularization. Int J Mol Sci 2020; 21:E2689. [PMID: 32294914 PMCID: PMC7216141 DOI: 10.3390/ijms21082689] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/09/2020] [Accepted: 04/10/2020] [Indexed: 12/15/2022] Open
Abstract
Choroidal neovascularization (CNV) is a pathological process in which aberrant blood vessels invade the subretinal space of the mammalian eye. It is a characteristic feature of the prevalent neovascular age-related macular degeneration (nAMD). Circulating microRNAs (cmiRNAs) are regarded as potentially valuable biomarkers for various age-related diseases, including nAMD. Here, we investigated cmiRNA expression in an established laser-induced CNV mouse model. Upon CNV induction in C57Bl/6 mice, blood-derived cmiRNAs were initially determined globally by RNA next generation sequencing, and the most strongly dysregulated cmiRNAs were independently replicated by quantitative reverse transcription PCR (RT-qPCR) in blood, retinal, and retinal pigment epithelium (RPE)/choroidal tissue. Our findings suggest that two miRNAs, mmu-mir-486a-5p and mmur-mir-92a-3p, are consistently dysregulated during CNV formation. Furthermore, in functional in vitro assays, a significant impact of mmu-mir-486a-5p and mmu-mir-92a-3p on murine microglial cell viability was observed, while mmu-mir-92a-3p also showed an impact on microglial mobility. Taken together, we report a robust dysregulation of two miRNAs in blood and RPE/choroid after laser-induced initiation of CNV lesions in mice, highlighting their potential role in pathology and eventual therapy of CNV-associated complications.
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Affiliation(s)
- Christina Kiel
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany; (C.K.); (P.B.); (T.S.); (F.G.)
| | - Patricia Berber
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany; (C.K.); (P.B.); (T.S.); (F.G.)
| | - Marcus Karlstetter
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital of Cologne, 50931 Cologne, Germany; (M.K.); (A.A.); (T.L.)
| | - Alexander Aslanidis
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital of Cologne, 50931 Cologne, Germany; (M.K.); (A.A.); (T.L.)
| | - Tobias Strunz
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany; (C.K.); (P.B.); (T.S.); (F.G.)
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital of Cologne, 50931 Cologne, Germany; (M.K.); (A.A.); (T.L.)
| | - Felix Grassmann
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany; (C.K.); (P.B.); (T.S.); (F.G.)
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, 171 77 Stockholm, Sweden
| | - Bernhard H.F. Weber
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany; (C.K.); (P.B.); (T.S.); (F.G.)
- Institute of Clinical Human Genetics, University Clinics Regensburg, 93053 Regensburg, Germany
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Angata T. Siglecs that Associate with DAP12. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1204:215-230. [PMID: 32152949 DOI: 10.1007/978-981-15-1580-4_9] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Siglecs are a family of transmembrane receptor-like glycan-recognition proteins expressed primarily on leukocytes. Majority of Siglecs have an intracellular sequence motif called immunoreceptor tyrosine-based inhibitory motif (ITIM) and associate with Src homology region 2 domain-containing tyrosine phosphatase-1 (SHP-1), and negatively regulate tyrosine phosphorylation-mediated intracellular signaling events. On the other hand, some Siglecs have a positively charged amino acid residue in the transmembrane domain and associate with DNAX activation protein of 12 kDa (DAP12), which in turn recruits spleen tyrosine kinase (Syk). These DAP12-associated Siglecs play diverse functions. For example, Siglec-15 is conserved throughout vertebrate evolution and plays a role in bone homeostasis by regulating osteoclast development and function. Human Siglec-14 and -16 have inhibitory counterparts (Siglec-5 and -11, respectively), which show extremely high sequence similarity with them at the extracellular domain but interact with SHP-1. The DAP12-associated Siglec in such "paired receptor" configuration counteracts the pathogens that exploit the inhibitory counterpart. Polymorphisms (mutations) that render DAP12-associated inactive Siglecs are found in humans, and some of these appear to be associated with sensitivity or resistance of human hosts to bacterially induced conditions. Studies of mouse Siglec-H have revealed complex and intriguing functions it plays in regulating adaptive immunity. Many questions remain unanswered, and further molecular and genetic studies of DAP12-associated Siglecs will yield valuable insights with translational relevance.
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Affiliation(s)
- Takashi Angata
- Institute of Biological Chemistry, Academia Sinica, 128, Section 2, Academia Road, Nangang District, Taipei, Taiwan.
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Bartling B, Rehfeld JS, Boßmann D, de Vries I, Fohrer J, Lammers F, Scheper T, Beutel S. Determination of the Structural Integrity and Stability of Polysialic Acid during Alkaline and Thermal Treatment. Molecules 2019; 25:E165. [PMID: 31906121 PMCID: PMC6982714 DOI: 10.3390/molecules25010165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/19/2019] [Accepted: 12/21/2019] [Indexed: 11/16/2022] Open
Abstract
Polysialic acid (polySia) is a linear homopolymer of varying chain lengths that exists mostly on the outer cell membrane surface of certain bacteria, such as Escherichia coli (E. coli) K1. PolySia, with an average degree of polymerization of 20 (polySia avDP20), possesses material properties that can be used for therapeutic applications to treat inflammatory neurodegenerative diseases. The fermentation of E. coli K1 enables the large-scale production of endogenous long-chain polySia (DP ≈ 130) (LC polySia), from which polySia avDP20 can be manufactured using thermal hydrolysis. To ensure adequate biopharmaceutical quality of the product, the removal of byproducts and contaminants, such as endotoxins, is essential. Recent studies have revealed that the long-term incubation in alkaline sodium hydroxide (NaOH) solutions reduces the endotoxin content down to 3 EU (endotoxin units) per mg, which is in the range of pharmaceutical applications. In this study, we analyzed interferences in the intramolecular structure of polySia caused by harsh NaOH treatment or thermal hydrolysis. Nuclear magnetic resonance (NMR) spectroscopy revealed that neither the incubation in an alkaline solution nor the thermal hydrolysis induced any chemical modification. In addition, HPLC analysis with a preceding 1,2-diamino-4,5-methylenedioxybenzene (DMB) derivatization demonstrated that the alkaline treatment did not induce any hydrolytic effects to reduce the maximum polymer length and that the controlled thermal hydrolysis reduced the maximum chain length effectively, while cost-effective incubation in alkaline solutions had no adverse effects on LC polySia. Therefore, both methods guarantee the production of high-purity, low-molecular-weight polySia without alterations in the structure, which is a prerequisite for the submission of a marketing authorization application as a medicinal product. However, a specific synthesis of low-molecular-weight polySia with defined chain lengths is only possible to a limited extent.
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Affiliation(s)
- Bastian Bartling
- Institute of Technical Chemistry, Leibniz University Hannover, 30167 Hannover, Germany; (B.B.); (J.S.R.); (D.B.); (I.d.V.); (T.S.)
| | - Johanna S. Rehfeld
- Institute of Technical Chemistry, Leibniz University Hannover, 30167 Hannover, Germany; (B.B.); (J.S.R.); (D.B.); (I.d.V.); (T.S.)
| | - Daniel Boßmann
- Institute of Technical Chemistry, Leibniz University Hannover, 30167 Hannover, Germany; (B.B.); (J.S.R.); (D.B.); (I.d.V.); (T.S.)
| | - Ingo de Vries
- Institute of Technical Chemistry, Leibniz University Hannover, 30167 Hannover, Germany; (B.B.); (J.S.R.); (D.B.); (I.d.V.); (T.S.)
| | - Jörg Fohrer
- Institute of Organic Chemistry, Leibniz University Hannover, 30167 Hannover, Germany;
| | - Frank Lammers
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, 65929 Frankfurt am Main, Germany;
| | - Thomas Scheper
- Institute of Technical Chemistry, Leibniz University Hannover, 30167 Hannover, Germany; (B.B.); (J.S.R.); (D.B.); (I.d.V.); (T.S.)
| | - Sascha Beutel
- Institute of Technical Chemistry, Leibniz University Hannover, 30167 Hannover, Germany; (B.B.); (J.S.R.); (D.B.); (I.d.V.); (T.S.)
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46
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Khan N, Kim SK, Gagneux P, Dugan LL, Varki A. Maximum reproductive lifespan correlates with CD33rSIGLEC gene number: Implications for NADPH oxidase-derived reactive oxygen species in aging. FASEB J 2019; 34:1928-1938. [PMID: 31907986 DOI: 10.1096/fj.201902116r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 12/22/2022]
Abstract
Humans and orcas are among the very rare species that have a prolonged post-reproductive lifespan (PRLS), during which the aging process continues. Reactive oxygen species (ROS) derived from mitochondria and from the NADPH oxidase (NOX) enzymes of innate immune cells are known to contribute to aging, with the former thought to be dominant. CD33-related-Siglecs are immune receptors that recognize self-associated-molecular-patterns and modulate NOX-derived-ROS. We herewith demonstrate a strong correlation of lifespan with CD33rSIGLEC gene number in 26 species, independent of body weight or phylogeny. The correlation is stronger when considering total CD33rSIGLEC gene number rather than those encoding inhibitory and activating subsets, suggesting that lifetime balancing of ROS is important. Combining independent lines of evidence including the short half-life and spontaneous activation of neutrophils, we calculate that even without inter-current inflammation, a major source of lifetime ROS exposure may actually be neutrophil NOX-derived. However, genomes of human supercentenarians (>110 years) do not harbor a significantly higher number of functional CD33rSIGLEC genes. Instead, lifespan correlation with CD33rSIGLEC gene number was markedly strengthened by excluding the post-reproductive lifespan of humans and orcas (R2 = 0.83; P < .0001). Thus, CD33rSIGLEC modulation of ROS likely contributes to maximum reproductive lifespan, but other unknown mechanisms could be important to PRLS.
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Affiliation(s)
- Naazneen Khan
- Glycobiology Research and Training Center, UC San Diego, La Jolla, CA, USA.,Center for Academic Research and Training in Anthropogeny, UC San Diego, La Jolla, CA, USA.,Department of Medicine, UC San Diego, La Jolla, CA, USA.,Department of Pathology, UC San Diego, La Jolla, CA, USA.,Department of Anthropology, UC San Diego, La Jolla, CA, USA.,Department of Cellular & Molecular Medicine, UC San Diego, La Jolla, CA, USA
| | - Stuart K Kim
- Department of Developmental Biology, Stanford University Medical Center, Stanford, CA, USA
| | - Pascal Gagneux
- Glycobiology Research and Training Center, UC San Diego, La Jolla, CA, USA.,Center for Academic Research and Training in Anthropogeny, UC San Diego, La Jolla, CA, USA.,Department of Medicine, UC San Diego, La Jolla, CA, USA.,Department of Pathology, UC San Diego, La Jolla, CA, USA.,Department of Anthropology, UC San Diego, La Jolla, CA, USA.,Department of Cellular & Molecular Medicine, UC San Diego, La Jolla, CA, USA
| | - Laura L Dugan
- Vanderbilt University Medical Center, Medicine-Geriatrics, Nashville, TN, USA.,VA Tennessee Valley Geriatric Research, Education and Clinical Center (GRECC), Nashville, TN, USA
| | - Ajit Varki
- Glycobiology Research and Training Center, UC San Diego, La Jolla, CA, USA.,Center for Academic Research and Training in Anthropogeny, UC San Diego, La Jolla, CA, USA.,Department of Medicine, UC San Diego, La Jolla, CA, USA.,Department of Pathology, UC San Diego, La Jolla, CA, USA.,Department of Anthropology, UC San Diego, La Jolla, CA, USA.,Department of Cellular & Molecular Medicine, UC San Diego, La Jolla, CA, USA
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Will-Orrego A, Qiu Y, Fassbender ES, Shen S, Aranda J, Kotagiri N, Maker M, Liao SM, Jaffee BD, Poor SH. Amount of Mononuclear Phagocyte Infiltrate Does Not Predict Area of Experimental Choroidal Neovascularization (CNV). J Ocul Pharmacol Ther 2019; 34:489-499. [PMID: 30188257 PMCID: PMC6152860 DOI: 10.1089/jop.2017.0131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Purpose: Mononuclear phagocytes (MNPs) are present in neovascular age-related macular degeneration (nv AMD) which is also called choroidal neovascularization (CNV). The number and phenotype of the MNPs depend upon the local environment in the CNV and effect of nv AMD therapy. We investigated ocular cell infiltration and conditions that modulate angiogenesis in a laser-induced mouse CNV model. Methods: We developed assays to quantify MNPs in our established mouse CNV model. One MNP assay quantified the number of subretinal cells peripheral to the CNV lesions. A second assay semiquantitatively assesses the number of MNPs localized to the CNV lesion. We used these assays to measure the effect of toll-like receptor-2 (TLR-2) activation, anti-vascular endothelial growth factor (VEGF) therapy, and chemokine (C-C motif) ligand 2 (Ccl2) genetic deletion on MNP infiltration after laser injury. Results: Laser injury induced blood vessel growth and infiltration of MNPs. Systemic administration of a TLR-2 activating peptide increased laser-induced CNV area, MNP cell numbers, and MNP density over the CNV lesions. Systemic administration of a VEGF antibody reduced CNV area, while Ccl2 genetic deletion increased CNV area. Despite the change in amount of angiogenesis, MNP infiltration was, surprisingly, unchanged in these 2 conditions. Conclusions: MNP quantification provides biological insights for candidate AMD therapies. The number of infiltrating MNP cells does not correlate with the amount of laser-induced CNV area.
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Affiliation(s)
- Adrian Will-Orrego
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
| | - Yubin Qiu
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
| | - Elizabeth S Fassbender
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
| | - Siyuan Shen
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
| | - Jorge Aranda
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
| | - Namrata Kotagiri
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
| | - Michael Maker
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
| | - Sha-Mei Liao
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
| | - Bruce D Jaffee
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
| | - Stephen H Poor
- Department of Ophthalmology, Novartis Institutes for Biomedical Research , Cambridge, Massachusetts
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48
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Schwarzer P, Kokona D, Ebneter A, Zinkernagel MS. Effect of Inhibition of Colony-Stimulating Factor 1 Receptor on Choroidal Neovascularization in Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 190:412-425. [PMID: 31783006 DOI: 10.1016/j.ajpath.2019.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 07/09/2019] [Accepted: 10/21/2019] [Indexed: 12/15/2022]
Abstract
Neovascular age-related macular degeneration is one of the leading causes of blindness. Microglia and macrophages play a critical role in choroidal neovascularization (CNV) and may, therefore, be potential targets to modulate the disease course. This study evaluated the effect of the colony-stimulating factor-1 receptor inhibitor PLX5622 on experimental laser-induced CNV. A 98% reduction of retinal microglia cells was observed in the retina 1 week after initiation of PLX5622 treatment, preventing accumulation of macrophages within the laser site and leading to a reduction of leukocytes within the choroid after CNV induction. Mice treated with PLX5622 had a significantly faster decrease of the CNV lesion size, as revealed by in vivo imaging and immunohistochemistry from day 3 to day 14 compared with untreated mice. Several inflammatory modulators, such as chemokine (C-C motif) ligand 9, granulocyte-macrophage colony-stimulating factor, soluble tumor necrosis factor receptor-I, IL-1α, and matrix metallopeptidase-2, were elevated in the acute phase of the disease when microglia were ablated with PLX5622, whereas other cytokines (eg, interferon-γ, IL-4, and IL-10) were reduced. Our results suggest that colony-stimulating factor-1 receptor inhibition may be a novel therapeutic target in patients with neovascular age-related macular degeneration.
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Affiliation(s)
- Petra Schwarzer
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern; and the Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Despina Kokona
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern; and the Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Andreas Ebneter
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern; and the Department for BioMedical Research, University of Bern, Bern, Switzerland
| | - Martin S Zinkernagel
- Department of Ophthalmology, Inselspital, Bern University Hospital, University of Bern, Bern; and the Department for BioMedical Research, University of Bern, Bern, Switzerland.
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49
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Siddiqui SS, Matar R, Merheb M, Hodeify R, Vazhappilly CG, Marton J, Shamsuddin SA, Al Zouabi H. Siglecs in Brain Function and Neurological Disorders. Cells 2019; 8:E1125. [PMID: 31546700 PMCID: PMC6829431 DOI: 10.3390/cells8101125] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/19/2019] [Accepted: 09/20/2019] [Indexed: 12/14/2022] Open
Abstract
Siglecs (Sialic acid-binding immunoglobulin-type lectins) are a I-type lectin that typically binds sialic acid. Siglecs are predominantly expressed in immune cells and generate activating or inhibitory signals. They are also shown to be expressed on the surface of cells in the nervous system and have been shown to play central roles in neuroinflammation. There has been a plethora of reviews outlining the studies pertaining to Siglecs in immune cells. However, this review aims to compile the articles on the role of Siglecs in brain function and neurological disorders. In humans, the most abundant Siglecs are CD33 (Siglec-3), Siglec-4 (myelin-associated glycoprotein/MAG), and Siglec-11, Whereas in mice the most abundant are Siglec-1 (sialoadhesin), Siglec-2 (CD22), Siglec-E, Siglec-F, and Siglec-H. This review is divided into three parts. Firstly, we discuss the general biological aspects of Siglecs that are expressed in nervous tissue. Secondly, we discuss about the role of Siglecs in brain function and molecular mechanism for their function. Finally, we collate the available information on Siglecs and neurological disorders. It is intriguing to study this family of proteins in neurological disorders because they carry immunoinhibitory and immunoactivating motifs that can be vital in neuroinflammation.
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Affiliation(s)
- Shoib Sarwar Siddiqui
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - Rachel Matar
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - Maxime Merheb
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - Rawad Hodeify
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - Cijo George Vazhappilly
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | - John Marton
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
| | | | - Hussain Al Zouabi
- Department of Biotechnology, American University of Ras Al Khaimah (AURAK), Ras Al Khaimah 10021, UAE.
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50
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Rashid K, Akhtar-Schaefer I, Langmann T. Microglia in Retinal Degeneration. Front Immunol 2019; 10:1975. [PMID: 31481963 PMCID: PMC6710350 DOI: 10.3389/fimmu.2019.01975] [Citation(s) in RCA: 200] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/05/2019] [Indexed: 12/18/2022] Open
Abstract
The retina is a complex tissue with multiple cell layers that are highly ordered. Its sophisticated structure makes it especially sensitive to external or internal perturbations that exceed the homeostatic range. This necessitates the continuous surveillance of the retina for the detection of noxious stimuli. This task is mainly performed by microglia cells, the resident tissue macrophages which confer neuroprotection against transient pathophysiological insults. However, under sustained pathological stimuli, microglial inflammatory responses become dysregulated, often worsening disease pathology. In this review, we provide an overview of recent studies that depict microglial responses in diverse retinal pathologies that have degeneration and chronic immune reactions as key pathophysiological components. We also discuss innovative immunomodulatory therapy strategies that dampen the detrimental immunological responses to improve disease outcome.
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Affiliation(s)
- Khalid Rashid
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Isha Akhtar-Schaefer
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, Cologne, Germany
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