Cold storage conditions modify microRNA expressions for platelet transfusion

MicroRNAs (miRNAs) are small RNA molecules that modulate gene and protein expression in hematopoiesis. Platelets are known to contain a fully functional miRNA machinery. While platelets used for transfusion are normally stored at room temperature, recent evidence suggests more favorable effects under a cold-storage condition, including higher adhesion and aggregation properties. Thus, we sought to determine whether functional differences in platelets are associated with the differential profiling of platelet miRNA expressions. To obtain the miRNA expression profile, next-generation sequencing was performed on human platelets obtained from 10 healthy subjects. The miRNAs were quantified after being stored in three different conditions: 1) baseline (before storage), 2) stored at 22°C with agitation for 72 h, and 3) stored at 4°C for 72 h. Following the identification of miRNAs by sequencing, the results were validated at the level of mature miRNAs from 18 healthy subjects, by using quantitative polymerase chain reaction (qPCR). Differential expression was observed for 125 miRNAs that were stored at 4°C and 9 miRNAs stored at 22°C as compared to the baseline. The validation study by qPCR confirmed that storage at 4°C increased the expression levels (fold change 95% CI) of mir-20a-5p (1.87, p<0.0001), mir-10a-3p (1.88, p<0.0001), mir-16-2-3p (1.54, p<0.01), and mir-223-5p (1.38, p<0.05), compared with those of the samples stored at 22°C. These results show that miRNAs correlate with platelet quality under specific storage conditions. The data indicate that miRNAs could be potentially used as biomarkers of platelet quality.