title: Key role of microRNA in the regulation of granulocyte macrophage colony-stimulating factor expression in murine alveolar epithelial cells during oxidative stress.
abstract: GM-CSF is an endogenous pulmonary cytokine produced by normal alveolar epithelial cells (AEC) that is a key defender of the alveolar space. AEC GM-CSF expression is suppressed by oxidative stress through alternations in mRNA turnover, an effect that is reversed by treatment with recombinant GM-CSF. We hypothesized that specific microRNA (miRNA) would play a key role in AEC GM-CSF regulation. A genome-wide miRNA microarray identified 19 candidate miRNA altered in primary AEC during oxidative stress with reversal by treatment with GM-CSF. Three of these miRNA (miR 133a, miR 133a*, and miR 133b) are also predicted to bind the GM-CSF 3'-untranslated region (UTR). PCR for the mature miRNA confirmed induction during oxidative stress that was reversed by treatment with GM-CSF. Experiments using a GM-CSF 3'-UTR reporter construct demonstrated that miR133a and miR133b effects on GM-CSF expression are through interactions with the GM-CSF 3'-UTR. Using lentiviral transduction of specific mimics and inhibitors in primary murine AEC, we determined that miR133a and miR133b suppress GM-CSF expression and that their inhibition both reverses oxidant-induced suppression of GM-CSF expression and increases basal expression of GM-CSF in cells in normoxia. In contrast, these miRNAs are not active in regulation of GM-CSF expression in murine EL4 T cells. Thus, members of the miR133 family play key roles in regulation of GM-CSF expression through effects on mRNA turnover in AEC during oxidative stress. Increased understanding of GM-CSF gene regulation may provide novel miRNA-based interventions to augment pulmonary innate immune defense in lung injury.
authors.affiliation: From the Department of Veterans Affairs Medical Center, Salt Lake City, Utah 84148 and.
authors.forename: Anne
authors.initials: A
authors.lastname: Sturrock
authors.forename: Mustafa
authors.initials: M
authors.lastname: Mir-Kasimov
authors.forename: Jessica
authors.initials: J
authors.lastname: Baker
authors.forename: Jesse
authors.initials: J
authors.lastname: Rowley
authors.forename: Robert
authors.initials: R
authors.lastname: Paine
mesh_terms: D020413:3' Untranslated Regions / Q000502:physiology*; D000818:Animals; D002460:Cell Line; D005786:Gene Expression Regulation / Q000502:physiology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D020413:3' Untranslated Regions; D035683:MicroRNAs; C517732:Mirn133 microRNA, mouse; D016178:Granulocyte-Macrophage Colony-Stimulating Factor
keywords: Array; Gene Regulation; Growth Factors; Lung Injury; MicroRNA; Microarray; Oxidative Stress