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Milham LT, Morris GP, Konen LM, Rentsch P, Avgan N, Vissel B. Quantification of AMPA receptor subunits and RNA editing-related proteins in the J20 mouse model of Alzheimer's disease by capillary western blotting. Front Mol Neurosci 2024; 16:1338065. [PMID: 38299128 PMCID: PMC10828003 DOI: 10.3389/fnmol.2023.1338065] [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: 11/14/2023] [Accepted: 12/29/2023] [Indexed: 02/02/2024] Open
Abstract
Introduction Accurate modelling of molecular changes in Alzheimer's disease (AD) dementia is crucial for understanding the mechanisms driving neuronal pathology and for developing treatments. Synaptic dysfunction has long been implicated as a mechanism underpinning memory dysfunction in AD and may result in part from changes in adenosine deaminase acting on RNA (ADAR) mediated RNA editing of the GluA2 subunit of AMPA receptors and changes in AMPA receptor function at the post synaptic cleft. However, few studies have investigated changes in proteins which influence RNA editing and notably, AD studies that focus on studying changes in protein expression, rather than changes in mRNA, often use traditional western blotting. Methods Here, we demonstrate the value of automated capillary western blotting to investigate the protein expression of AMPA receptor subunits (GluA1-4), the ADAR RNA editing proteins (ADAR1-3), and proteins known to regulate RNA editing (PIN1, WWP2, FXR1P, and CREB1), in the J20 AD mouse model. We describe extensive optimisation and validation of the automated capillary western blotting method, demonstrating the use of total protein to normalise protein load, in addition to characterising the optimal protein/antibody concentrations to ensure accurate protein quantification. Following this, we assessed changes in proteins of interest in the hippocampus of 44-week-old J20 AD mice. Results We observed an increase in the expression of ADAR1 p110 and GluA3 and a decrease in ADAR2 in the hippocampus of 44-week-old J20 mice. These changes signify a shift in the balance of proteins that play a critical role at the synapse. Regression analysis revealed unique J20-specific correlations between changes in AMPA receptor subunits, ADAR enzymes, and proteins that regulate ADAR stability in J20 mice, highlighting potential mechanisms mediating RNA-editing changes found in AD. Discussion Our findings in J20 mice generally reflect changes seen in the human AD brain. This study underlines the importance of novel techniques, like automated capillary western blotting, to assess protein expression in AD. It also provides further evidence to support the hypothesis that a dysregulation in RNA editing-related proteins may play a role in the initiation and/or progression of AD.
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Affiliation(s)
- Luke T. Milham
- Centre for Neuroscience and Regenerative Medicine, St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Sydney, NSW, Australia
- St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Gary P. Morris
- Centre for Neuroscience and Regenerative Medicine, St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Sydney, NSW, Australia
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Lyndsey M. Konen
- Centre for Neuroscience and Regenerative Medicine, St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Sydney, NSW, Australia
| | - Peggy Rentsch
- Centre for Neuroscience and Regenerative Medicine, St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Sydney, NSW, Australia
- St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Nesli Avgan
- Centre for Neuroscience and Regenerative Medicine, St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Sydney, NSW, Australia
| | - Bryce Vissel
- Centre for Neuroscience and Regenerative Medicine, St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Sydney, NSW, Australia
- St Vincent’s Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
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Okinaka Y, Shinagawa Y, Claussen C, Gul S, Matsui I, Matsui Y, Taguchi A. RNA Analysis of Circulating Leukocytes in Patients with Alzheimer's Disease. J Alzheimers Dis 2024; 97:1673-1683. [PMID: 38277293 PMCID: PMC10894574 DOI: 10.3233/jad-230874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2023] [Indexed: 01/28/2024]
Abstract
Background One of the key symptoms of Alzheimer's disease (AD) is the impairment of short-term memory. Hippocampal neurogenesis is essential for short-term memory and is known to decrease in patients with AD. Impaired short-term memory and impaired neurogenesis are observed in aged mice alongside changes in RNA expression of gap junction and metabolism-related genes in circulating leukocytes. Moreover, after penetrating the blood-brain barrier via the SDF1/CXCR4 axis, circulating leukocytes directly interact with hippocampal neuronal stem cells via gap junctions. Objective Evaluation of RNA expression profiles in circulating leukocytes in patients with AD. Methods Patients with AD (MMSE≧23, n = 10) and age-matched controls (MMSE≧28, n = 10) were enrolled into this study. RNA expression profiles of gap junction and metabolism-related genes in circulating leukocytes were compared between the groups (jRCT: 1050210166). Results The ratios of gap junction and metabolism-related genes were significantly different between patients with AD and age-matched controls. However, due to large inter-individual variations, there were no statistically significant differences in the level of single RNA expression between these groups. Conclusions Our findings suggest a potential connection between the presence of circulating leukocytes and the process of hippocampal neurogenesis in individuals with AD. Analyzing RNA in circulating leukocytes holds promise as a means to offer novel insights into the pathology of AD, distinct from conventional markers.
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Affiliation(s)
- Yuka Okinaka
- Department of Regenerative Medicine Research, Institute of Biomedical Research and Innovation at Kobe, Hyogo, Japan
| | - Yoshiyuki Shinagawa
- Department of Regenerative Medicine Research, Institute of Biomedical Research and Innovation at Kobe, Hyogo, Japan
- Global Planning Group, Kaneka Corporation, Osaka, Japan
| | - Carsten Claussen
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Hamburg, Germany
- Fraunhofer Cluster of Excellence for Immune-Mediated Diseases CIMD, Hamburg, Germany
| | - Sheraz Gul
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Hamburg, Germany
- Fraunhofer Cluster of Excellence for Immune-Mediated Diseases CIMD, Hamburg, Germany
| | - Ikuko Matsui
- Matsui Dietary and Dementia Clinic, Hyogo, Japan
| | | | - Akihiko Taguchi
- Department of Regenerative Medicine Research, Institute of Biomedical Research and Innovation at Kobe, Hyogo, Japan
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