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Caetano L, Pinheiro H, Patrício P, Mateus-Pinheiro A, Alves ND, Coimbra B, Baptista FI, Henriques SN, Cunha C, Santos AR, Ferreira SG, Sardinha VM, Oliveira JF, Ambrósio AF, Sousa N, Cunha RA, Rodrigues AJ, Pinto L, Gomes CA. Adenosine A 2A receptor regulation of microglia morphological remodeling-gender bias in physiology and in a model of chronic anxiety. Mol Psychiatry 2017; 22:1035-1043. [PMID: 27725661 DOI: 10.1038/mp.2016.173] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 08/01/2016] [Accepted: 08/18/2016] [Indexed: 12/12/2022]
Abstract
Developmental risk factors, such as the exposure to stress or high levels of glucocorticoids (GCs), may contribute to the pathogenesis of anxiety disorders. The immunomodulatory role of GCs and the immunological fingerprint found in animals prenatally exposed to GCs point towards an interplay between the immune and the nervous systems in the etiology of these disorders. Microglia are immune cells of the brain, responsive to GCs and morphologically altered in stress-related disorders. These cells are regulated by adenosine A2A receptors, which are also involved in the pathophysiology of anxiety. We now compare animal behavior and microglia morphology in males and females prenatally exposed to the GC dexamethasone. We report that prenatal exposure to dexamethasone is associated with a gender-specific remodeling of microglial cell processes in the prefrontal cortex: males show a hyper-ramification and increased length whereas females exhibit a decrease in the number and in the length of microglia processes. Microglial cells re-organization responded in a gender-specific manner to the chronic treatment with a selective adenosine A2A receptor antagonist, which was able to ameliorate microglial processes alterations and anxiety behavior in males, but not in females.
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Affiliation(s)
- L Caetano
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - H Pinheiro
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI Consortium, Coimbra, Portugal
| | - P Patrício
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - A Mateus-Pinheiro
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - N D Alves
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - B Coimbra
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - F I Baptista
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI Consortium, Coimbra, Portugal
| | - S N Henriques
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - C Cunha
- ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - A R Santos
- ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - S G Ferreira
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,CNC.IBILI Consortium, Coimbra, Portugal
| | - V M Sardinha
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - J F Oliveira
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - A F Ambrósio
- Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI Consortium, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - N Sousa
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - R A Cunha
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,CNC.IBILI Consortium, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - A J Rodrigues
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - L Pinto
- Life and Health Sciences Research Institute (ICVS), University of Minho, Braga, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Portugal
| | - C A Gomes
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Institute for Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,CNC.IBILI Consortium, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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Castilho AF, Liberal JT, Baptista FI, Gaspar JM, Carvalho AL, Ambrósio AF. Elevated glucose concentration changes the content and cellular localization of AMPA receptors in the retina but not in the hippocampus. Neuroscience 2012; 219:23-32. [PMID: 22659015 DOI: 10.1016/j.neuroscience.2012.05.056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 05/22/2012] [Accepted: 05/22/2012] [Indexed: 10/28/2022]
Abstract
Diabetic retinopathy and diabetic encephalopathy are two common complications of diabetes mellitus. The impairment of glutamatergic neurotransmission in the retina and hippocampus has been suggested to be involved in the pathogenesis of these diabetic complications. In this study, we investigated the effect of elevated glucose concentration and diabetes on the protein content and surface expression of AMPA receptor subunits in the rat retina and hippocampus. We have used two models, cultured retinal and hippocampal cells exposed to elevated glucose concentration and an animal model of streptozotocin-induced type 1 diabetes. The immunoreactivity of GluA1, GluA2 and GluA4 was evaluated by Western blot and immunocytochemistry. The levels of these subunits at the plasma membrane were evaluated by biotinylation and purification of plasma membrane-associated proteins. Elevated glucose concentration increased the total levels of GluA2 subunit of AMPA receptors in retinal neural cells, but not of the subunits GluA1 or GluA4. However, at the plasma membrane, elevated glucose concentration induced an increase of all AMPA receptor subunits. In cultured hippocampal neurons, elevated glucose concentration did not induce significant alterations in the levels of AMPA receptor subunits. In the retinas of diabetic rats there were no persistent changes in the levels of AMPA receptor subunits comparing to aged-matched control retinas. Also, no consistent changes were detected in the levels of GluA1, GluA2 or GluA4 in the hippocampus of diabetic rats. We demonstrate that elevated glucose concentration induces early changes in AMPA receptor subunits, mainly in GluA2 subunit, in retinal neural cells. Conversely, hippocampal neurons seem to remain unaffected by elevated glucose concentration, concerning the expression of AMPA receptors, suggesting that AMPA receptors are more susceptible to the stress caused by elevated glucose concentration in retinal cells than in hippocampal neurons.
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Affiliation(s)
- A F Castilho
- Centre of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
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Gaspar JM, Castilho Á, Baptista FI, Liberal J, Ambrósio AF. Long-term exposure to high glucose induces changes in the content and distribution of some exocytotic proteins in cultured hippocampal neurons. Neuroscience 2010; 171:981-92. [PMID: 20950673 DOI: 10.1016/j.neuroscience.2010.10.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 09/15/2010] [Accepted: 10/06/2010] [Indexed: 01/19/2023]
Abstract
A few studies have reported the existence of depletion of synaptic vesicles, and changes in neurotransmitter release and in the content of exocytotic proteins in the hippocampus of diabetic rats. Recently, we found that diabetes alters the levels of synaptic proteins in hippocampal nerve terminals. Hyperglycemia is considered the main trigger of diabetic complications, although other factors, such as low insulin levels, also contribute to diabetes-induced changes. Thus, the aim of this work was to evaluate whether long-term elevated glucose per se, which mimics prolonged hyperglycemia, induces significant changes in the content and localization of synaptic proteins involved in exocytosis in hippocampal neurons. Hippocampal cell cultures were cultured for 14 days and were exposed to high glucose (50 mM) or mannitol (osmotic control; 25 mM plus 25 mM glucose), for 7 days. Cell viability and nuclear morphology were evaluated by MTT and Hoechst assays, respectively. The protein levels of vesicle-associated membrane protein-2 (VAMP-2), synaptosomal-associated protein-25 (SNAP-25), syntaxin-1, synapsin-1, synaptophysin, synaptotagmin-1, rabphilin 3a, and also of vesicular glutamate and GABA transporters (VGluT-1 and VGAT), were evaluated by immunoblotting, and its localization was analyzed by immunocytochemistry. The majority of the proteins were not affected. However, elevated glucose decreased the content of SNAP-25 and increased the content of synaptotagmin-1 and VGluT-1. Moreover, there was an accumulation of syntaxin-1, synaptotagmin-1 and VGluT-1 in the cell body of some hippocampal neurons exposed to high glucose. No changes were detected in mannitol-treated cells. In conclusion, elevated glucose per se did not induce significant changes in the content of the majority of the synaptic proteins studied in hippocampal cultures, with the exception of SNAP-25, synaptotagmin-1 and VGluT-1. However, there was an accumulation of some proteins in cell bodies of hippocampal neurons exposed to elevated glucose, suggesting that the trafficking of these proteins to the synapse may be compromised. Moreover, these results also suggest that other factors, in addition to hyperglycemia, certainly contribute to alterations detected in synaptic proteins in diabetic animals.
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Affiliation(s)
- J M Gaspar
- Center of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, 3004-548 Coimbra, Portugal
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