Lyophilized human cells stored at room temperature preserve multiple RNA species at excellent quality for RNA sequencing. Lyophilized human cells stored at room temperature preserve multiple RNA species at excellent quality for RNA sequencing

Purpose: We aimed to examine whether eukaryotic cell lyophilization and long-term storage would be feasible as an environmentally friendly and cheap alternative to cryogenic storage or the use of FFPE samples for large-scale RNA profiling studies. Brief method: On three different days three million GM12873 cells were taken up in 0.1 M trehalose, subjected to lyophilization (freeze-drying) and then stored for two weeks at room temperature in the presence of CaCl2 in a dark, tightly sealed box. Fresh paired control cells were pelleted and taken up in trizol without lyophilization. Total RNA was isolated using a modified trizol method, quantified and subjected to mRNA-Seq library preparation. Samples were sequenced using a NextSeq 500 instrument to 75 bp (single-end). Raw reads were aligned to the hg19 genomic build with TopHat 2.0.7 and gene expression quantification was performed using Cufflinks. Results: We found that lyophilized cells are highly similar in all inferred RNA-Seq quality metrics compared to their non-lyophilized controls and are useful sources of high-quality RNA for both small and large-scale studies. Conslusion: Lyophilization might be the preservation technique of choice in the future for studies aiming to involve large sample sets, such as clinical studies. Overall design: mRNA profiles of three paired control and lyophilized cells stored at room temperature for two weeks.