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Caldeira C, Oliveira AF, Cunha C, Vaz AR, Falcão AS, Fernandes A, Brites D. Microglia change from a reactive to an age-like phenotype with the time in culture. Front Cell Neurosci 2014; 8:152. [PMID: 24917789 PMCID: PMC4040822 DOI: 10.3389/fncel.2014.00152] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 05/13/2014] [Indexed: 01/25/2023] Open
Abstract
Age-related neurodegenerative diseases have been associated with chronic neuroinflammation and microglia activation. However, cumulative evidence supports that inflammation only occurs at an early stage once microglia change the endogenous characteristics with aging and switch to irresponsive/senescent and dystrophic phenotypes with disease progression. Thus, it will be important to have the means to assess the role of reactive and aged microglia when studying advanced brain neurodegeneration processes and age-associated related disorders. Yet, most studies are done with microglia from neonates since there are no adequate means to isolate degenerating microglia for experimentation. Indeed, only a few studies report microglia isolation from aged animals, using either short-term cultures or high concentrations of mitogens in the medium, which trigger microglia reactivity. The purpose of this study was to develop an experimental process to naturally age microglia after isolation from neonatal mice and to characterize the cultured cells at 2 days in vitro (DIV), 10 DIV, and 16 DIV. We found that 2 DIV (young) microglia had predominant amoeboid morphology and markers of stressed/reactive phenotype. In contrast, 16 DIV (aged) microglia evidenced ramified morphology and increased matrix metalloproteinase (MMP)-2 activation, as well as reduced MMP-9, glutamate release and nuclear factor kappa-B activation, in parallel with decreased expression of Toll-like receptor (TLR)-2 and TLR-4, capacity to migrate and phagocytose. These findings together with the reduced expression of microRNA (miR)-124, and miR-155, decreased autophagy, enhanced senescence associated beta-galactosidase activity and elevated miR-146a expression, are suggestive that 16 DIV cells mainly correspond to irresponsive/senescent microglia. Data indicate that the model represent an opportunity to understand and control microglial aging, as well as to explore strategies to recover microglia surveillance function.
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Affiliation(s)
- Cláudia Caldeira
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Centro de Investigação Interdisciplinar Egas Moniz, Egas Moniz - Cooperativa de Ensino Superior, CRL, Campus Universitário Monte de Caparica, Portugal
| | - Ana F Oliveira
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Carolina Cunha
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Ana R Vaz
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Ana S Falcão
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Adelaide Fernandes
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
| | - Dora Brites
- Research Institute for Medicines - iMed.ULisboa, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal ; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa Lisboa, Portugal
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Cui L, Li Y, Ma G, Wang Y, Cai Y, Liu S, Chen Y, Li J, Xie Y, Liu G, Zhao B, Li K. A functional polymorphism in the promoter region of microRNA-146a is associated with the risk of Alzheimer disease and the rate of cognitive decline in patients. PLoS One 2014; 9:e89019. [PMID: 24586483 PMCID: PMC3934871 DOI: 10.1371/journal.pone.0089019] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/14/2014] [Indexed: 12/16/2022] Open
Abstract
miR146a is well known for its regulatory role in the immune response and inflammation. Recent studies have demonstrated the links between miR146a and Alzheimer disease (AD) and suggested that miR146a may be involved in neuroinflammation and the metabolism of amyloid-β (Aβ), which are critical events in AD pathology. Although genetic studies have focused on the association between the miR146a gene and susceptibility to several diseases, no association study of miR146a variability with AD has been conducted. In this report, we performed a case-control association study to analyze the genotype and allele distributions of the miR146a, rs2910464 and rs57095329 polymorphisms in a Chinese population consisting of 292 AD cases and 300 healthy controls. We found a significant difference in the genotypes and allele frequencies of rs57095329 between the AD cases and the controls (p = 0.0147 and p = 0.0184, respectively), where the AA genotype of rs57095329 was associated with an increased risk of AD as well the cognitive decline in AD patients. Additionally, the AA genotype of rs57095329 exhibited significantly higher miR146a expression than the GG+GA genotypes of rs2910164 in the peripheral blood cells (PBMCs) of healthy individuals and had a stronger effect on the production of IL-6 and IL-1β when the cells were stimulated with LPS. Our data provide preliminary evidence that the rs57095329 polymorphism in the miR146a promoter is involved in the genetic susceptibility to AD, and this risk AA genotype may increase the expression of miR146a and influence certain proinflammatory cytokines, thus playing a role in the pathogenesis of AD.
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Affiliation(s)
- Lili Cui
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
| | - You Li
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
| | - Guoda Ma
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
| | - Yan Wang
- Clinical Research Center of Guangdong Medical College, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
| | - Yujie Cai
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
| | - Shengyuan Liu
- Department of Chronic Disease, Shenzhen Nanshan Center for Chronic Disease Control, Shenzhen, PR China
| | - Yanyan Chen
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
| | - Jia Li
- Intensive Care Unit, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
| | - Yuliu Xie
- Intensive Care Unit, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
| | - Gen Liu
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
- Institute of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
| | - Bin Zhao
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
- Institute of Neurology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
- * E-mail: (BZ); (KSL)
| | - Keshen Li
- Guangdong Key Laboratory of Age-Related Cardiac and Cerebral Diseases, Affiliated Hospital of Guangdong Medical College, Zhanjiang, PR China
- * E-mail: (BZ); (KSL)
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