title: Regulation of fibrinogen production by microRNAs.
abstract: Elevated levels of fibrinogen are associated with increased risk of cardiovascular disease, whereas low fibrinogen can lead to a bleeding disorder. We investigated whether microRNAs (miRNAs), known to act as post-transcriptional regulators of gene expression, regulate fibrinogen production. Using transfection of a library of 470 annotated human miRNA precursor molecules in HuH7 hepatoma cells and quantitative measurements of fibrinogen production, we identified 23 miRNAs with down-regulating (up to 64% decrease) and 4 with up-regulating effects (up to 129% increase) on fibrinogen production. Among the down-regulating miRNAs, we investigated the mechanism of action of 3 hsa-miR-29 family members and hsa-miR-409-3p. Overexpression of hsa-miR-29 members led to decreased steady-state levels of all fibrinogen gene (FGA, FGB, and FGG) transcripts in HuH7 cells. Luciferase reporter gene assays demonstrated that this was independent of miRNA-fibrinogen 3'-untranslated region interactions. In contrast, overexpression of hsa-miR-409-3p specifically lowered fibrinogen Bβ mRNA levels, and this effect was dependent on a target site in the fibrinogen Bβ mRNA 3'-untranslated region. This study adds to the known mechanisms that control fibrinogen production, points toward a potential cause of variable circulating fibrinogen levels, and demonstrates that a screening approach can identify miRNAs that regulate clinically important proteins.
authors.affiliation: Department of Genetic Medicine and Development, University of Geneva Faculty of Medicine, Geneva, Switzerland.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Fort
authors.forename: Christelle
authors.initials: C
authors.lastname: Borel
authors.forename: Eugenia
authors.initials: E
authors.lastname: Migliavacca
authors.forename: Stylianos E
authors.initials: SE
authors.lastname: Antonarakis
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Fish
authors.forename: Marguerite
authors.initials: M
authors.lastname: Neerman-Arbez
mesh_terms: D020413:3' Untranslated Regions; D002460:Cell Line; D045744:Cell Line, Tumor; D005340:Fibrinogen / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; D035683:MicroRNAs; D005340:Fibrinogen