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Fernández-de Frutos M, Galán-Chilet I, Goedeke L, Kim B, Pardo-Marqués V, Pérez-García A, Herrero JI, Fernández-Hernando C, Kim J, Ramírez CM. MicroRNA 7 Impairs Insulin Signaling and Regulates Aβ Levels through Posttranscriptional Regulation of the Insulin Receptor Substrate 2, Insulin Receptor, Insulin-Degrading Enzyme, and Liver X Receptor Pathway. Mol Cell Biol 2019; 39:e00170-19. [PMID: 31501273 PMCID: PMC6817752 DOI: 10.1128/mcb.00170-19] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/14/2019] [Accepted: 08/10/2019] [Indexed: 02/07/2023] Open
Abstract
Brain insulin resistance is a key pathological feature contributing to obesity, diabetes, and neurodegenerative disorders, including Alzheimer's disease (AD). Besides the classic transcriptional mechanism mediated by hormones, posttranscriptional regulation has recently been shown to regulate a number of signaling pathways that could lead to metabolic diseases. Here, we show that microRNA 7 (miR-7), an abundant microRNA in the brain, targets insulin receptor (INSR), insulin receptor substrate 2 (IRS-2), and insulin-degrading enzyme (IDE), key regulators of insulin homeostatic functions in the central nervous system (CNS) and the pathology of AD. In this study, we found that insulin and liver X receptor (LXR) activators promote the expression of the intronic miR-7-1 in vitro and in vivo, along with its host heterogeneous nuclear ribonucleoprotein K (HNRNPK) gene, encoding an RNA binding protein (RBP) that is involved in insulin action at the posttranscriptional level. Our data show that miR-7 expression is altered in the brains of diet-induced obese mice. Moreover, we found that the levels of miR-7 are also elevated in brains of AD patients; this inversely correlates with the expression of its target genes IRS-2 and IDE. Furthermore, overexpression of miR-7 increased the levels of extracellular Aβ in neuronal cells and impaired the clearance of extracellular Aβ by microglial cells. Taken together, these results represent a novel branch of insulin action through the HNRNPK-miR-7 axis and highlight the possible implication of these posttranscriptional regulators in a range of diseases underlying metabolic dysregulation in the brain, from diabetes to Alzheimer's disease.
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Affiliation(s)
| | - Inmaculada Galán-Chilet
- Genomic and Genetic Diagnosis Unit, Biomedical Research Institute Hospital Clinic of Valencia (INCLIVA), Valencia, Spain
| | - Leigh Goedeke
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, USA
- Integrative Cell Signaling and Neurobiology of Metabolism Program, Department of Comparative Medicine and Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Byungwook Kim
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | | | - Ana Pérez-García
- IMDEA Research Institute of Food and Health Sciences, Madrid, Spain
| | - J Ignacio Herrero
- Department of Cell Biology and Immunology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Carlos Fernández-Hernando
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, USA
- Integrative Cell Signaling and Neurobiology of Metabolism Program, Department of Comparative Medicine and Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jungsu Kim
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Cristina M Ramírez
- IMDEA Research Institute of Food and Health Sciences, Madrid, Spain
- Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, Connecticut, USA
- Integrative Cell Signaling and Neurobiology of Metabolism Program, Department of Comparative Medicine and Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
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