1
|
Highet B, Wiseman JA, Mein H, Parker R, Ryan B, Turner CP, Jing Y, Singh-Bains MK, Liu P, Dragunow M, Faull RLM, Murray HC, Curtis MA. PSA-NCAM Regulatory Gene Expression Changes in the Alzheimer's Disease Entorhinal Cortex Revealed with Multiplexed in situ Hybridization. J Alzheimers Dis 2023; 92:371-390. [PMID: 36744342 DOI: 10.3233/jad-220986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is the most common form of dementia and is characterized by a substantial reduction of neuroplasticity. Our previous work demonstrated that neurons involved in memory function may lose plasticity because of decreased protein levels of polysialylated neural cell adhesion molecule (PSA-NCAM) in the entorhinal cortex (EC) of the human AD brain, but the cause of this decrease is unclear. OBJECTIVE To investigate genes involved in PSA-NCAM regulation which may underlie its decrease in the AD EC. METHODS We subjected neurologically normal and AD human EC sections to multiplexed fluorescent in situ hybridization and immunohistochemistry to investigate genes involved in PSA-NCAM regulation. Gene expression changes were sought to be validated in both human tissue and a mouse model of AD. RESULTS In the AD EC, a cell population expressing a high level of CALB2 mRNA and a cell population expressing a high level of PST mRNA were both decreased. CALB2 mRNA and protein were not decreased globally, indicating that the decrease in CALB2 was specific to a sub-population of cells. A significant decrease in PST mRNA expression was observed with single-plex in situ hybridization in middle temporal gyrus tissue microarray cores from AD patients, which negatively correlated with tau pathology, hinting at global loss in PST expression across the AD brain. No significant differences in PSA-NCAM or PST protein expression were observed in the MAPT P301S mouse brain at 9 months of age. CONCLUSION We conclude that PSA-NCAM dysregulation may cause subsequent loss of structural plasticity in AD, and this may result from a loss of PST mRNA expression. Due PSTs involvement in structural plasticity, intervention for AD may be possible by targeting this disrupted plasticity pathway.
Collapse
Affiliation(s)
- Blake Highet
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand
| | - James A Wiseman
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand
| | - Hannah Mein
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Remai Parker
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand
| | - Brigid Ryan
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand
| | - Clinton P Turner
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand.,Department of Anatomical Pathology, LabPlus, Auckland City Hospital, New Zealand
| | - Yu Jing
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Malvindar K Singh-Bains
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand
| | - Ping Liu
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Mike Dragunow
- Department of Pharmacology and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand
| | - Richard L M Faull
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand
| | - Helen C Murray
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand
| | - Maurice A Curtis
- Department of Anatomy and Medical Imaging and Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag, Auckland, New Zealand
| |
Collapse
|
2
|
Rachubik P, Szrejder M, Rogacka D, Typiak M, Audzeyenka I, Kasztan M, Pollock DM, Angielski S, Piwkowska A. Insulin controls cytoskeleton reorganization and filtration barrier permeability via the PKGIα-Rac1-RhoA crosstalk in cultured rat podocytes. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119301. [PMID: 35642843 DOI: 10.1016/j.bbamcr.2022.119301] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 05/16/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Podocyte foot processes are an important cellular layer of the glomerular barrier that regulates glomerular permeability. Insulin via the protein kinase G type Iα (PKGIα) signaling pathway regulates the balance between contractility and relaxation (permeability) of the podocyte barrier by regulation of the actin cytoskeleton. This mechanism was shown to be disrupted in diabetes. Rho family guanosine-5'-triphosphates (GTPases) are dynamic modulators of the actin cytoskeleton and expressed in cells that form the glomerular filtration barrier. Thus, changes in Rho GTPase activity may affect glomerular permeability to albumin. The present study showed that Rho family GTPases control podocyte migration and permeability. Moreover these processes are regulated by insulin in PKGIα-dependent manner. Modulation of the PKGI-dependent activity of Rac1 and RhoA GTPases with inhibitors or small-interfering RNA impair glomerular permeability to albumin. We also demonstrated this mechanism in obese, insulin-resistant Zucker rats. We propose that PKGIα-Rac1-RhoA crosstalk is necessary in proper organization of the podocyte cytoskeleton and consequently the stabilization of glomerular architecture and regulation of filtration barrier permeability.
Collapse
Affiliation(s)
- Patrycja Rachubik
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdańsk, Poland
| | - Maria Szrejder
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdańsk, Poland
| | - Dorota Rogacka
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdańsk, Poland; University of Gdańsk, Faculty of Chemistry, Department of Molecular Biotechnology, Gdańsk, Poland
| | - Marlena Typiak
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdańsk, Poland; University of Gdańsk, Faculty of Biology, Department of General and Medical Biochemistry, Gdańsk, Poland
| | - Irena Audzeyenka
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdańsk, Poland; University of Gdańsk, Faculty of Chemistry, Department of Molecular Biotechnology, Gdańsk, Poland
| | - Małgorzata Kasztan
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - David M Pollock
- Cardio-Renal Physiology and Medicine, Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Stefan Angielski
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdańsk, Poland
| | - Agnieszka Piwkowska
- Mossakowski Medical Research Institute, Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Gdańsk, Poland; University of Gdańsk, Faculty of Chemistry, Department of Molecular Biotechnology, Gdańsk, Poland.
| |
Collapse
|
3
|
The sialoglycan-Siglec-E checkpoint axis in dexamethasone-induced immune subversion in glioma-microglia transwell co-culture system. Immunol Res 2020; 67:348-357. [PMID: 31741237 DOI: 10.1007/s12026-019-09106-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Dexamethasone (Dex) is considered as the main steroid routinely used in the standard therapy of brain tumor-induced edema. Strong immunosuppressive effects of Dex on effector systems of the immune system affect the patients' antitumor immunity and may thereby worsen the prognosis. Siglecs and their interacting sialoglycans have been described as a novel glyco-immune checkpoint axis that promotes cancer immune evasion. Despite the aberrant glycosylation in cancer is described, mechanisms involved in regulation of immune checkpoints in gliomas are not fully understood. The aim of this study was to investigate the effect of Dex on the Siglec-sialic acid interplay and determine its significance in immune inversion in monocultured and co-cultured microglia and glioma cells. Both monocultured and co-cultured in transwell system embryonic stem cell-derived microglia (ESdM) and glioma GL261 cells were exposed to Dex. Cell viability, immune inversion markers, and interaction between sialic acid and Siglec-E were detected by flow cytometry. Cell invasion was analyzed by scratch-wound migration assay using inverted phase-contrast microscopy. Exposure to Dex led to significant changes in IL-1β, IL-10, Iba-1, and Siglec-E in co-cultured microglia compared to naïve or monocultured cells. These alterations were accompanied by increased α2.8-sialylation and Siglec-E fusion protein binding to co-cultured glioma cell membranes. This study suggests that the interplay between sialic acids and Siglecs is a sensitive immune checkpoint axis and may be crucial for Dex-induced dampening of antitumor immunity. The targeting of sialic acid-Siglec glyco-immune checkpoint can be a novel therapeutic method in glioma therapy.
Collapse
|
4
|
Effect of expression alteration in flanking genes on phenotypes of St8sia2-deficient mice. Sci Rep 2019; 9:13634. [PMID: 31541165 PMCID: PMC6754417 DOI: 10.1038/s41598-019-50006-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/28/2019] [Indexed: 12/31/2022] Open
Abstract
ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 2 (ST8SIA2) synthesizes polysialic acid (PSA), which is essential for brain development. Although previous studies reported that St8sia2-deficient mice that have a mixed 129 and C57BL/6 (B6) genetic background showed mild and variable phenotypes, the reasons for this remain unknown. We hypothesized that this phenotypic difference is caused by diversity in the expression or function of flanking genes of St8sia2. A genomic polymorphism and gene expression analysis in the flanking region revealed reduced expression of insulin-like growth factor 1 receptor (Igf1r) on the B6 background than on that of the 129 strain. This observation, along with the finding that administration of an IGF1R agonist during pregnancy increased litter size, suggests that the decreased expression of Igf1r associated with ST8SIA2 deficiency caused lethality. This study demonstrates the importance of gene expression level in the flanking regions of a targeted null allele having an effect on phenotype.
Collapse
|
5
|
Coppieters N, Merry S, Patel R, Highet B, Curtis MA. Polysialic acid masks neural cell adhesion molecule antigenicity. Brain Res 2018; 1710:199-208. [PMID: 30584926 DOI: 10.1016/j.brainres.2018.12.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 12/31/2022]
Abstract
The neural cell adhesion molecule (NCAM) is a transmembrane protein involved in major cellular processes. The addition of polysialic acid (PSA), a post-translational modification (PTM) almost exclusively carried by NCAM, alters NCAM properties and functions and is therefore tightly regulated. Changes in NCAM and PSA-NCAM take place during development and ageing and occur in various diseases. The presence of PTMs can reduce the accessibility of antibodies to their epitopes and lead to false negative results. Thus, it is vital to identify antibodies that can specifically detect their target regardless of the presence of PTMs. In the present study, four commercially available NCAM antibodies were characterized by western blot and immunocytochemistry. Antibody specificity was determined by decreasing NCAM expression with small interfering RNA and subsequently determining whether the antibodies still produced a signal. In addition, PSA was digested with endoneuraminidase N to assess whether removing PSA improves NCAM detection with these antibodies. Our study revealed that the presence of PSA on NCAM reduced antibody accessibility to the epitope and consequently masked NCAM antigenicity for both techniques investigated. Moreover, three of the four antibodies tested were specific for the detection of NCAM by western blot and by immunocytochemistry. Altogether, this study demonstrates the importance of choosing the correct antibody to study NCAM depending on the technique of interest and underlines the importance of taking PTMs into account when using antibody-based techniques for the study of NCAM.
Collapse
Affiliation(s)
- Natacha Coppieters
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Sonya Merry
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Rachna Patel
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Blake Highet
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Maurice A Curtis
- Centre for Brain Research, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
| |
Collapse
|