microRNA microarray of aortae from 4-week male Fbn1mgR/mgR and wild-type mice [4-week_miRNA]

Thoracic aortic aneurysms (TAA) in Marfan syndrome, caused by fibrillin-1 mutations, are characterized by elevated cytokines and fragmentated elastic laminae in the aortic wall. This study explored whether and how specific fibrillin-1-regulated miRNAs mediate inflammatory cytokine expression and elastic laminae degradation in TAA. miRNA expression profiling at early and late TAA stages using a severe Marfan mouse model (Fbn1mgR/mgR) revealed a spectrum of differentially regulated miRNAs. Bioinformatic analyses predicted the involvement of these miRNAs in inflammatory and extracellular matrix related pathways. Complementing mRNA microarray demonstrated the upregulation of multiple pro-inflammatory cytokines and matrix metalloproteases. Correlation analyses between the altered miRNAs and mRNAs present miR-122, the most downregulated miRNAs in the TAA tissue of Fbn1mgR/mgR, to be a core regulatory miRNA to pro-inflammatory cytokines, Ccl2 and Il1b, which were upregulated in the TAA tissues. 3 miRNAs were downregulated and 14 upregulated more than 2-fold Microarray analysis was performed for miRNAs using the GeneChip miRNA 4.0 Array from Affymetrix. RNA extraction, RNA quality control, cDNA preparation and labeling, and the arrays were conducted as standard procedures at the Genome Quebec Innovation Centre at McGill University. Four ascending aorta samples in each group from 4 -week old wild-type and Fbn1mgR/mgR mice were prepared as described above, and snap-frozen in liquid nitrogen to preserve the integrity of RNA.