1
|
Carello-Collar G, Bellaver B, Ferreira PCL, Ferrari-Souza JP, Ramos VG, Therriault J, Tissot C, De Bastiani MA, Soares C, Pascoal TA, Rosa-Neto P, Souza DO, Zimmer ER. The GABAergic system in Alzheimer's disease: a systematic review with meta-analysis. Mol Psychiatry 2023; 28:5025-5036. [PMID: 37419974 DOI: 10.1038/s41380-023-02140-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/17/2023] [Accepted: 06/16/2023] [Indexed: 07/09/2023]
Abstract
The γ-aminobutyric acid (GABA)ergic system is the primary inhibitory neurotransmission system in the mammalian brain. Its dysregulation has been shown in multiple brain conditions, but in Alzheimer's disease (AD) studies have provided contradictory results. Here, we conducted a systematic review with meta-analysis to investigate whether the GABAergic system is altered in AD patients compared to healthy controls (HC), following the PRISMA 2020 Statement. We searched PubMed and Web of Science from database inception to March 18th, 2023 for studies reporting GABA, glutamate decarboxylase (GAD) 65/67, GABAA, GABAB, and GABAC receptors, GABA transporters (GAT) 1-3 and vesicular GAT in the brain, and GABA levels in the cerebrospinal fluid (CSF) and blood. Heterogeneity was estimated using the I2 index, and the risk of bias was assessed with an adapted questionnaire from the Joanna Briggs Institute Critical Appraisal Tools. The search identified 3631 articles, and 48 met the final inclusion criteria (518 HC, mean age 72.2, and 603 AD patients, mean age 75.6). Random-effects meta-analysis [standardized mean difference (SMD)] revealed that AD patients presented lower GABA levels in the brain (SMD = -0.48 [95% CI = -0.7, -0.27], adjusted p value (adj. p) < 0.001) and in the CSF (-0.41 [-0.72, -0.09], adj. p = 0.042), but not in the blood (-0.63 [-1.35, 0.1], adj. p = 0.176). In addition, GAD65/67 (-0.67 [-1.15, -0.2], adj. p = 0.006), GABAA receptor (-0.51 [-0.7, -0.33], adj. p < 0.001), and GABA transporters (-0.51 [-0.92, -0.09], adj. p = 0.016) were lower in the AD brain. Here, we showed a global reduction of GABAergic system components in the brain and lower GABA levels in the CSF of AD patients. Our findings suggest the GABAergic system is vulnerable to AD pathology and should be considered a potential target for developing pharmacological strategies and novel AD biomarkers.
Collapse
Affiliation(s)
- Giovanna Carello-Collar
- Graduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
| | - Bruna Bellaver
- Graduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Pamela C L Ferreira
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - João Pedro Ferrari-Souza
- Graduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Vanessa G Ramos
- Graduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
| | - Joseph Therriault
- McGill Centre for Studies in Aging, McGill University, Montreal, QC, H4H 1R3, Canada
- Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, McGill University, Montreal, QC, H4H 1R3, Canada
- Departments of Neurology and Neurosurgery, McGill University, Montreal, QC, H3A 1A1, Canada
| | - Cécile Tissot
- McGill Centre for Studies in Aging, McGill University, Montreal, QC, H4H 1R3, Canada
- Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, McGill University, Montreal, QC, H4H 1R3, Canada
- Departments of Neurology and Neurosurgery, McGill University, Montreal, QC, H3A 1A1, Canada
| | - Marco A De Bastiani
- Department of Pharmacology, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
| | - Carolina Soares
- Graduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Tharick A Pascoal
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Pedro Rosa-Neto
- McGill Centre for Studies in Aging, McGill University, Montreal, QC, H4H 1R3, Canada
- Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, McGill University, Montreal, QC, H4H 1R3, Canada
- Departments of Neurology and Neurosurgery, McGill University, Montreal, QC, H3A 1A1, Canada
- Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Diogo O Souza
- Graduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
- Department of Biochemistry, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil
| | - Eduardo R Zimmer
- Graduate Program in Biological Sciences: Biochemistry, Department of Biochemistry, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil.
- McGill Centre for Studies in Aging, McGill University, Montreal, QC, H4H 1R3, Canada.
- Translational Neuroimaging Laboratory, McGill University Research Centre for Studies in Aging, McGill University, Montreal, QC, H4H 1R3, Canada.
- Department of Pharmacology, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil.
- Graduate Program in Biological Sciences: Pharmacology and Therapeutics, Department of Pharmacology, Institute of Health Basic Sciences, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, 90035-003, Brazil.
- Brain Institute of Rio Grande Do Sul, Pontifical Catholic University of Rio Grande Do Sul, Porto Alegre, RS, 90610-000, Brazil.
| |
Collapse
|
10
|
Takanaga H, Ohtsuki S, Terasaki T. GAT2/BGT-1 as a system responsible for the transport of gamma-aminobutyric acid at the mouse blood-brain barrier. J Cereb Blood Flow Metab 2001; 21:1232-9. [PMID: 11598501 DOI: 10.1097/00004647-200110000-00012] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In this study, the gamma-aminobutyric acid (GABA) transporter at the blood-brain barrier (BBB) was identified by reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and immunostaining analysis, and the transport mechanism was characterized using a conditionally immortalized mouse brain capillary endothelial cell line (TM-BBB) as an in vitro model of the BBB. gamma-Aminobutyric acid transport was studied by the cellular uptake of [ 3 H]GABA. [3H]GABA uptake by TM-BBB cells was Na (+)-, Cl(-)-, and concentration-dependent. The corresponding Michaelis-Menten constant was 679 +/- 80 micromol/L and the maximal uptake rate was 4,790 +/- 494 pmol/(mg protein x 5 minutes). [3H]GABA uptake by TM-BBB cells was significantly inhibited by betaine, beta-alanine, nipecotic acid, taurine, and quinidine, whereas probenecid, L-proline, creatine, and glycine had no effect. This type of inhibition is consistent with the predominant involvement of the GAT2/BGT-1 transporter in TM-BBB cells. RT-PCR analysis showed that GAT2/BGT-1 mRNA was expressed in TM-BBB cells, whereas Western blot analysis showed that TM-BBB cells and mouse brain capillaries express GAT2/BGT-1 protein. Moreover, confocal immunofluorescent microscopy of dual-labeled mouse brain sections demonstrated the colocalization of GAT2/BGT-1 and P-glycoprotein, a BBB-specific marker, on brain capillaries labeled with anti-GAT2/BGT-1 antibody and anti-P-glycoprotein antibody, respectively. These results are evidence that GAT2/BGT-1 is expressed at the BBB and is involved in GABA transport across the BBB.
Collapse
Affiliation(s)
- H Takanaga
- Department of Molecular Biopharmacy and Genetics, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | | | | |
Collapse
|