[Expression Analysis of miRNA Profiles in Apheresis Platelets during Storage]

To study the expression profiles changes of miRNA in apheresis platelets after 1, 3 and 5 days of storage.

The apheresis platelets were collected from 20 volunteer blood donors. After mixing fully, the platelets were stored in a shaker with (22±2) ℃ horizontal oscillation. The samples were taken on the 1st, 3rd and 5th day, and used to sequence for miRNAs by DNA nanoball (DNB) sequencing technology, which were named as C_1, C_3 and C_5, respectively. The expression level of platelets miRNA was standardized by transcripts per kilobase million (TPM) algorithm. MiRNAs with P-value < 0.001 and the expression difference of more than two times were considered as significant difference between two groups. The expression of miRNAs was verified by real-time fluorescence quantitative PCR (RT-qPCR).

By DNB sequencing, there were 688, 730, and 679 platelet miRNAs expressed in C_1, C_3 and C_5 group, respectively. Cluster analysis showed that the expression profile of miRNAs changed significantly. The expression level of the first 20 high abundance miRNAs was about 4/5 of the total amounts of expressed miRNAs in each group, which the top five miRNAs were miR-21-5p, miR-26a-5p, miR-199a-3p, miR-126-3p, and let-7f-5p. The correlation of high abundance platelet miRNAs among the three groups was high (R2=0.876, R2=0.979, R2=0.937, respectively) and the differences were not statistically significant (P>0.05). Compared with the differential expression of platelet miRNAs with more than 1 000 TPM in the C_3 and C_1 group, there were 6 differentially expressed miRNAs, including 3 up-regulated (miR-146a-5p, miR-379-5p, and miR-486-5p) and 3 down-regulated (miR-652-3p, miR-142-5p, and miR-7-5p). While in the C_5 and C_1 group, there were 4 differentially expressed miRNAs, including 2 up-regulated (miR-146a-5p and let-7b-5p) and 2 down-regulated (miR-30d-5p and miR-142-5p). Compared with the differentially expression of platelet miRNAs between 1-1 000 TPM in the C_3 and C_1 group, there were 133 differentially expressed miRNAs, in which 99 were up-regulated and 34 were down-regulated. While in the C_5 and C_1 group, there were 77 differentially expressed miRNAs, in which 31 were up-regulated and 46 were down-regulated. The six selected differentially expressed miRNAs verified by RT-qPCR were consistent with those of sequencing.

The expression profiles of platelets miRNAs change significantly among 1, 3, and 5 d of storage in vitro.