Late Embryogenesis Abundant (LEA) proteins confer water stress tolerance to mammalian somatic cells

Late Embryogenesis Abundant (LEA) proteins are commonly found in plants and other organisms capable of undergoing severe and reversible dehydration, a phenomenon termed "anhydrobiosis". Here, we have produced a tagged version for three different LEA proteins: pTag-RAB17-GFP-N, Zea mays dehydrin-1dhn, expressed in the nucleo-cytoplasm; pTag-WCOR410-RFP, Tricum aestivum cold acclimation protein WCOR410, binds to cellular membranes, and pTag-LEA-BFP, Artemia franciscana LEA protein group 3 that targets the mitochondria. Sheep fibroblasts transfected with single or all three LEA proteins were subjected to air drying under controlled conditions. After rehydration, cell viability and functionality of the membrane/mitochondria were assessed. After 4 h of air drying, cells from the un-transfected control group were almost completely nonviable (1% cell alive), while cells expressing LEA proteins showed high viability (more than 30%), with the highest viability (58%) observed in fibroblasts expressing all three LEA proteins. Growth rate was markedly compromised in control cells, while LEA-expressing cells proliferated at a rate comparable to non-air-dried cells. Plasmalemma, cytoskeleton and mitochondria appeared unaffected in LEA-expressing cells, confirming the protection conferred by LEA proteins on these organelles during dehydration stress. This is likely to be an effective strategy when aiming to confer desiccation tolerance to mammalian cells.