(D) HASMCs were cultured in the growth medium (M231 + SMGS) at day 0 then switched from growth conditions to differentiation medium (M231 + SMDS) for 8 days. Quantitative real-time PCR analysis of mature let-7 family in HASMCs. SNORD47 was used to normalize the variability in template loading. Histogram of qRT-PCR results are three independent experiments. 