Figure 1.

miRNA expression profile in native hfRPE, neuroretina, choroid, and primary cultures of hfRPE. A) Heat map was plotted in Heatmap Builder1.0 with ΔC_t from each miRNA using the mean C_t of miR-16 and let-7a as the reference. Yellow denotes high expression; blue denotes relatively lower expression. Entire data set was assigned to 50 color bins and sorted based on ΔC_t in an RPE sample, with high expression (low ΔC_t) at top and low expression (high ΔC_t) at bottom. At right, the 6 most highly enriched RPE miRNAs are highlighted in light green. Intensity scale: bright blue indicates lowest expression (ΔC_t=−18); bright yellow indicates highest expression (ΔC_t=8). Highest and lowest expression levels differ by ≈7 × 10⁷-fold (2²⁶), which is within the detection range of TaqMan Q-PCR for miRNAs (24). B) Six miRNAs enriched in human RPE. Fold difference was calculated using average ΔΔC_t from 3 biological repeats. A miRNA is considered as enriched in RPE if its expression level is significantly higher (≥10-fold) than that in neuroretina and choroid at both 16 and 20 WG. Student’s t test was run for each of the 4 pairs of comparison (P<0.05, 2-tailed, unpaired, unequal variance). C, D) Five miRNAs enriched in human neuroretina (C) and 8 miRNAs enriched in human choroid (D). Fold difference was calculated using the same criteria as for RPE in A.