Dataset - PONE-D-20-09507 - Usefulness of circulating miR-146a and miR-16-5p microRNAs as prognostic biomarkers in community-acquired pneumonia

This dataset shows a prospective observational study performed in a cohort of 153 patients admitted to hospital with CAP.

Clinical and analytical variables were collected, and the main outcome variable was 30-day mortality.

Small RNA was purified from patients´ plasma samples by column-based protocol, and retrotranscribed to cDNA (Exiqon's miRCURY ™ series kits), adding synthetic RNA controls (spike-in). The quality of the process was evaluated (QC control) and only 117 samples passed the test.

FIRST STEP: Eight samples paired by age and gender were selected (4 patients who had suffered a cardiovascular event or death during follow-up and 4 who had not) and a panel of 752 human miRNAs was tested (miRCURY LNA ™ Universal - Ready-to-Use Human Panel , Exiqon), in order to determine a preliminary pattern of differential miRNA expression between patients with different CAP evolution.

SECOND STEP: According to the preliminary data obtained, 25 candidate miRNAs were selected: 5 intended to be used as normalizers, 5 selected by statistical criteria (univariate association with mortality) and 15 selected from an exhaustive bibliographic search on miRNAs, sepsis, inflammation and / or cardiovascular disease, prioritizing those that appeared in a greater number of publications and those related to respiratory diseases. RT-PCR was carried out by hybridization with double-stranded flurochrome (ExiLENT SYBR® Green Master Mix) using the C1000 Touch CFX384 thermocycler (Bio-Rad).

The relative amount of each miRNA was calculated with ∆Ct = CtmiRNA - CtUniSp2, and it was later normalized using the GeNorm algorithm. The final data was calculated with the formula 2-∆Ct and the values were expressed as the fold change (FC) of each miRNA with respect to UniSP2.