title: MicroRNA-130a represses transcriptional activity of aquaporin 4 M1 promoter.
abstract: Aquaporins (AQPs) are transmembrane water channels ubiquitously expressed in mammalian tissues. They play prominent roles in maintaining cellular fluid balance. Although expression of AQP1, -3, -4, -5, -8, -9, and -11 has been reported in the central nervous system, it is AQP4 that is predominately expressed. Its importance in fluid regulation in cerebral edema conditions has been highlighted in several studies, and we have also shown that translational regulation of AQP4 by miR-320a could prove to be useful in infarct volume reduction in middle cerebral artery occluded rat brain. There is evidence for the existence of two AQP4 transcripts (M1 and M23) in the brain arising from two alternative promoters. Because the AQP4 M1 isoform exhibits greater water permeability, in this study, we explored the possibility of microRNA-based transcriptional regulation of the AQP4 M1 promoter. Using RegRNA software, we identified 34 microRNAs predicted to target the AQP4 M1 promoter region. MicroRNA profiling, quantitative stem-loop PCR, and luciferase reporter assays revealed that miR-130a, -152, -668, -939, and -1280, which were highly expressed in astrocytes, could regulate the promoter activity. Of these, miR-130a was identified as a strong transcriptional repressor of the AQP4 M1 isoform. In vivo studies revealed that LNA(TM) anti-miR-130a could up-regulate the AQP4 M1 transcript and its protein to bring about a reduction in cerebral infarct and promote recovery.
authors.affiliation: Department of Biochemistry and Neuroscience Research Centre, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore.
authors.forename: Sugunavathi
authors.initials: S
authors.lastname: Sepramaniam
authors.forename: Lim Kai
authors.initials: LK
authors.lastname: Ying
authors.forename: Arunmozhiarasi
authors.initials: A
authors.lastname: Armugam
authors.forename: E M
authors.initials: EM
authors.lastname: Wintour
authors.forename: Kandiah
authors.initials: K
authors.lastname: Jeyaseelan
mesh_terms: D000818:Animals; D051401:Aquaporin 4 / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D002545:Brain Ischemia / Q000235:genetics / Q000378:metabolism; D015687:Cell Hypoxia / Q000235:genetics; D045744:Cell Line, Tumor; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D002534:Hypoxia, Brain / Q000235:genetics / Q000378:metabolism; D049410:Luciferases, Renilla / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000235:genetics; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014158:Transcription, Genetic
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; C546086:MIRN30b microRNA, human; D035683:MicroRNAs; D009841:Oligonucleotides; D020033:Protein Isoforms; C477371:locked nucleic acid; D049410:Luciferases, Renilla