Spaceflight altered the gene and protein expression of the membrane transporter proteins in Jurkat cells

Drug transporter proteins are transmembrane proteins that mediate molecule transport at the cell membrane by energy-dependent mechanisms.  We postulated that spaceflight and microgravity may cause changes to cell membrane structure, therefore affecting the expression of drug transporter proteins.  We investigated the global gene expression changes and the expression of multidrug resistance proteins: Pgp, MRP1, MRP3, MRP4, LRP and BCRP, in space-flown Jurkat cells. Fluid Processing Apparatus (FPAs) were used in this study. A set of FPAs was prepared as ground controls (F_Ground) and fixated shortly after launching. The flight samples were flown on the Soyuz TMA-11 and fresh medium were added shortly after docking in the ISS. After 30 minutes, another set of FPAs was added fixative (designated as F_T 0 ) meanwhile another set were fixed after 72 hours incubation at 37°C (designated as F_T 72 ). The number of cells increased from F_Ground to F_T 0 and to F_T 72 . Post-flight analysis found that only CD3, MRP1 and BCRP showed significant changes. The flight samples showed a decrease in MRP1 expression at F_T 72 compared to F_T 0 . Expression of BCRP was also significantly decreased in flight samples compared to F_Ground. qRT-PCR results showed that MRP1 mRNA expression complement with the protein expression but mRNA of BCRP showed different expression from the protein expression. Microarray analysis showed that the voltage-gated K + channel gene, Kv.1 was differentially expressed at different time points and this was also shown in the RT-PCR assay. We suggest that cellular membrane adapted to spaceflight by modulating the expression of membrane transporter proteins.