Dual-Color MicroRNA Array Analysis Reveals Compartment-Specific Differential Expression in Diabetic vs. Normal DBA/2J Mouse Kidney Cortex and Medulla

This study profiles microRNA expression in mouse kidney tissues comparing diabetic and normal conditions. A total of 16 samples from the cortex and medulla compartments were analyzed from male DBA/2J mice (6–8 weeks old). RNA quality was rigorously assessed, followed by labeling with the miRCURY LNA™ microRNA Hi-Power Labeling Kit. In a dual-color experimental setup, the sample RNA was labeled with Cy3, and a Cy5-labeled reference was used. Arrays were hybridized under automated conditions, scanned with an Agilent G2565BA Microarray Scanner, and the data were processed using background correction and global Lowess normalization. Differential expression analysis, performed using both t-tests (with Benjamini–Hochberg correction) and ANOVA, identified a subset of microRNAs with significant expression differences between diabetic and normal kidneys. The experimental design compares microRNA expression profiles between diabetic and normal mouse kidneys, with additional segmentation into cortex and medulla compartments. Key aspects include: Sample Collection: Sixteen samples from male DBA/2J mice (6–8 weeks) covering both kidney compartments. RNA Quality Control: Evaluation via Agilent Bioanalyzer and Nanodrop to ensure high integrity and purity of RNA. Labeling & Hybridization: Dual-color labeling where sample RNA is conjugated with Cy3 and reference RNA with Cy5; note that while all samples include Cy3 data. Hybridization was performed using automated Tecan hybridization stations following manufacturer protocols. Scanning & Data Acquisition: Arrays were scanned in an ozone-controlled environment (to prevent dye bleaching) with the Agilent G2565BA scanner. Images were analyzed using ImaGene® software. Data Processing & Analysis: Background correction (using the Normexp method with an offset of 10) and global Lowess normalization were applied to the data. Subsequent statistical analyses (t-tests with multiple testing correction and ANOVA) were used to determine differentially expressed microRNAs.