Protein kinase B (AKT) upregulation and Thy-1-αvβ3 integrin-induced phosphorylation of Connexin43 by activated AKT in astrogliosis

Journal of Neuroinflammation

Research

Rocío Artigas¹  Alejandro H. Corvalán²  Pascal Schneider³  Alejandro Chamorro⁴  Ramón Pérez-Núñez⁴  Andrew F. G. Quest⁴  Lisette Leyton⁴  María Fernanda González⁴  Pamela Contreras⁴  Ana María Avalos⁵  Brigitte van Zundert⁶  Christopher Reyes⁷  Pablo R. Moya⁷ 

[1] Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Pontificia Universidad Católica de Chile (PUC), 833-1150, Santiago, Chile;Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Pontificia Universidad Católica de Chile (PUC), 833-1150, Santiago, Chile;Department of Hematology and Oncology, Facultad de Medicina, Pontificia Universidad Católica de Chile (PUC), 833-1150, Santiago, Chile;Department of Biochemistry, University of Lausanne, 1066, Epalinges, Switzerland;Department of Cell and Molecular Biology, Cellular Communication Laboratory, Center for Studies On Exercise, Metabolism and Cancer (CEMC), Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, 838-0453, Santiago, Chile;Advanced Center for Chronic Diseases (ACCDiS), Facultad de Medicina, Universidad de Chile, 838-0453, Santiago, Chile;Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile;Institute of Biomedical Sciences (ICB), Faculty of Medicine & Faculty of Life Sciences, Universidad Andres Bello, 837-0186, Santiago, Chile;Department of Neurology, University of Massachusetts Chan Medical School, 01655, Worcester, MA, USA;Instituto de Fisiología, Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile;

关键词: Brain damage;    Inflammation;    Astrogliosis;    ALS model;    Bioinformatics analysis;    PI3K/AKT signaling pathway;    Connexin43;   

DOI  :  10.1186/s12974-022-02677-7

 received in 2021-12-24, accepted in 2022-12-18,  发布年份 2022

来源: Springer

【 摘 要 】

BackgroundIn response to brain injury or inflammation, astrocytes undergo hypertrophy, proliferate, and migrate to the damaged zone. These changes, collectively known as "astrogliosis", initially protect the brain; however, astrogliosis can also cause neuronal dysfunction. Additionally, these astrocytes undergo intracellular changes involving alterations in the expression and localization of many proteins, including αvβ3 integrin. Our previous reports indicate that Thy-1, a neuronal glycoprotein, binds to this integrin inducing Connexin43 (Cx43) hemichannel (HC) opening, ATP release, and astrocyte migration. Despite such insight, important links and molecular events leading to astrogliosis remain to be defined.MethodsUsing bioinformatics approaches, we analyzed different Gene Expression Omnibus datasets to identify changes occurring in reactive astrocytes as compared to astrocytes from the normal mouse brain. In silico analysis was validated by both qRT-PCR and immunoblotting using reactive astrocyte cultures from the normal rat brain treated with TNF and from the brain of a hSOD1G93A transgenic mouse model. We evaluated the phosphorylation of Cx43 serine residue 373 (S373) by AKT and ATP release as a functional assay for HC opening. In vivo experiments were also performed with an AKT inhibitor (AKTi).ResultsThe bioinformatics analysis revealed that genes of the PI3K/AKT signaling pathway were among the most significantly altered in reactive astrocytes. mRNA and protein levels of PI3K, AKT, as well as Cx43, were elevated in reactive astrocytes from normal rats and from hSOD1G93A transgenic mice, as compared to controls. In vitro, reactive astrocytes stimulated with Thy-1 responded by activating AKT, which phosphorylated S373Cx43. Increased pS373Cx43 augmented the release of ATP to the extracellular medium and AKTi inhibited these Thy-1-induced responses. Furthermore, in an in vivo model of inflammation (brain damage), AKTi decreased the levels of astrocyte reactivity markers and S373Cx43 phosphorylation.ConclusionsHere, we identify changes in the PI3K/AKT molecular signaling network and show how they participate in astrogliosis by regulating the HC protein Cx43. Moreover, because HC opening and ATP release are important in astrocyte reactivity, the phosphorylation of Cx43 by AKT and the associated increase in ATP release identify a potential therapeutic window of opportunity to limit the adverse effects of astrogliosis.

【 授权许可】

CC BY   
© The Author(s) 2023

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