title: Antagonism of microRNA-122 in mice by systemically administered LNA-antimiR leads to up-regulation of a large set of predicted target mRNAs in the liver.
abstract: MicroRNA-122 (miR-122) is an abundant liver-specific miRNA, implicated in fatty acid and cholesterol metabolism as well as hepatitis C viral replication. Here, we report that a systemically administered 16-nt, unconjugated LNA (locked nucleic acid)-antimiR oligonucleotide complementary to the 5' end of miR-122 leads to specific, dose-dependent silencing of miR-122 and shows no hepatotoxicity in mice. Antagonism of miR-122 is due to formation of stable heteroduplexes between the LNA-antimiR and miR-122 as detected by northern analysis. Fluorescence in situ hybridization demonstrated uptake of the LNA-antimiR in mouse liver cells, which was accompanied by markedly reduced hybridization signals for mature miR-122 in treated mice. Functional antagonism of miR-122 was inferred from a low cholesterol phenotype and de-repression within 24 h of 199 liver mRNAs showing significant enrichment for miR-122 seed matches in their 3' UTRs. Expression profiling extended to 3 weeks after the last LNA-antimiR dose revealed that most of the changes in liver gene expression were normalized to saline control levels coinciding with normalized miR-122 and plasma cholesterol levels. Combined, these data suggest that miRNA antagonists comprised of LNA are valuable tools for identifying miRNA targets in vivo and for studying the biological role of miRNAs and miRNA-associated gene-regulatory networks in a physiological context.
authors.affiliation: Santaris Pharma, Bøge Allé 3, DK-2970 Hørsholm, Denmark.
authors.forename: Joacim
authors.initials: J
authors.lastname: Elmén
authors.forename: Morten
authors.initials: M
authors.lastname: Lindow
authors.forename: Asli
authors.initials: A
authors.lastname: Silahtaroglu
authors.forename: Mads
authors.initials: M
authors.lastname: Bak
authors.forename: Mette
authors.initials: M
authors.lastname: Christensen
authors.forename: Allan
authors.initials: A
authors.lastname: Lind-Thomsen
authors.forename: Maj
authors.initials: M
authors.lastname: Hedtjärn
authors.forename: Jens Bo
authors.initials: JB
authors.lastname: Hansen
authors.forename: Henrik Frydenlund
authors.initials: HF
authors.lastname: Hansen
authors.forename: Ellen Marie
authors.initials: EM
authors.lastname: Straarup
authors.forename: Keith
authors.initials: K
authors.lastname: McCullagh
authors.forename: Phil
authors.initials: P
authors.lastname: Kearney
authors.forename: Sakari
authors.initials: S
authors.lastname: Kauppinen
mesh_terms: D000818:Animals; D001483:Base Sequence; D005260:Female; D020869:Gene Expression Profiling; D020868:Gene Silencing; D006367:HeLa Cells; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D035683:MicroRNAs / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D009841:Oligonucleotides / Q000008:administration & dosage / Q000494:pharmacology* / Q000633:toxicity; D012333:RNA, Messenger / Q000378:metabolism*; D016415:Sequence Alignment; D015854:Up-Regulation
chemical_list: D035683:MicroRNAs; D009841:Oligonucleotides; D012333:RNA, Messenger; C477371:locked nucleic acid