title: Identification of novel microRNAs in post-transcriptional control of Nrf2 expression and redox homeostasis in neuronal, SH-SY5Y cells.
abstract: Nuclear factor-erythroid 2-related factor 2 (Nrf2/NFE2L2), a redox-sensitive transcription factor plays a critical role in adaptation to cellular stress and affords cellular defense by initiating transcription of antioxidative and detoxification genes. While a protein can be regulated at multiple levels, control of Nrf2 has been largely studied at post-translational regulation points by Keap1. Importantly, post-transcriptional/translational based regulation of Nrf2 is less understood and to date there are no reports on such mechanisms in neuronal systems. In this context, studies involving the role of microRNAs (miRs) which are normally considered as fine tuning regulators of protein production through translation repression and/or post-transcriptional alterations, are in place. In the current study, based on in-silico analysis followed by immunoblotting and real time analysis, we have identified and validated for the first time that human NFE2L2 could be targeted by miR153/miR27a/miR142-5p/miR144 in neuronal, SH-SY5Y cells. Co-transfection studies with individual miR mimics along with either WT 3' UTR of human Nrf2 or mutated miRNA targeting seed sequence within Nrf2 3' UTR, demonstrated that Nrf2 is a direct regulatory target of these miRs. In addition, ectopic expression of miR153/miR27a/miR142-5p/miR144 affected Nrf2 mRNA abundance and nucleo-cytoplasmic concentration of Nrf2 in a Keap1 independent manner resulting in inefficient transactivating ability of Nrf2. Furthermore, forced expression of miRs diminished GCLC and GSR expression resulting in alteration of Nrf2 dependent redox homeostasis. Finally, bioinformatics based miRNA-disease network analysis (MDN) along with extended computational network analysis of Nrf2 associated pathologic processes suggests that if in a particular cellular scenario where any of these miR153/miR27a/miR142-5p/miR144 either individually or as a group is altered, it could affect Nrf2 thus triggering and/or determining the fate of wide range of disease outcomes.
authors.affiliation: Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, Texas, USA. madhu.narasimhan@ttuhsc.edu
authors.forename: Madhusudhanan
authors.initials: M
authors.lastname: Narasimhan
authors.forename: Dhyanesh
authors.initials: D
authors.lastname: Patel
authors.forename: Dhanashree
authors.initials: D
authors.lastname: Vedpathak
authors.forename: Marylatha
authors.initials: M
authors.lastname: Rathinam
authors.forename: George
authors.initials: G
authors.lastname: Henderson
authors.forename: Lenin
authors.initials: L
authors.lastname: Mahimainathan
mesh_terms: D045744:Cell Line, Tumor; D005786:Gene Expression Regulation; D006706:Homeostasis / Q000235:genetics*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D010084:Oxidation-Reduction; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics
chemical_list: C555159:MIRN142 microRNA, human; C554293:MIRN144 microRNA, human; C556500:MIRN153 microRNA, human; C531388:MIRN27 microRNA, human; D035683:MicroRNAs; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human