Quantitation of RNA Expression

Total RNA was isolated from serum samples using TRIzol according to the manufacturer’s instructions (Invitrogen, Carlsbad, California, USA). For each sample, the total RNA content was determined by measuring the absorbance at 260 nm and the purity was ascertained in terms of A260/A280. First strand cDNAs of the miRNAs and mRNAs were synthesized using the Mir-X miRNA first strand synthesis kit and PrimeScript RT reagent kit with gDNA eraser (Takara Biotechnology, Dalian, China) respectively. RT-PCR was performed using 2 µl of each cDNA template and the FastStart SYBR Green Kit (Roche, East Sussex, UK) on the ABI 7500 Fast cycler (Applied Biosystems, Darmstadt, Germany)^{41 (link)}. The primer sequences are shown in Supplementary Information-Table S2.