Protective Functions of Group 3 Late Embryogenesis Abundant (G3LEA) Proteins in Enterococcus faecium During Vancomycin Treatment

Late embryogenesis abundant (LEA) proteins protect organisms from various environmental stresses; however, the underlying mechanism of LEA mediated therapeutic evasion is still unclear in both eukaryotes and prokaryotes. In this study, group 3 LEA protein (G3LEA) of vancomycin-resistant Enterococcus faecium under sublethal concentration of vancomycin stress was evaluated and shown to have two functions: the first is the reduction of reactive oxygen species (ROS) content, preventing apoptosis by suppressing apoptotic proteins Cas3 and MAOB, and the second is activating specific drug efflux pumps. Sublethal vancomycin model was established with using Propidium Iodide (PI) stain. Real-time PCR was conducted to evaluate the expression of G3lea. Flow cytometry and confocal microscope using Anti- G3LEA, anti- MAOB, and anti- Cas3 were performed to assess the expression of G3LEA. Under sublethal vancomycin stress, G3LEA is upregulated, suppressing the expression of apoptotic markers and increasing specific efflux markers. These results suggest that G3LEA protein suppresses antibiotic mediated apoptosis in prokaryotic cells and plays a key role in understanding and preventing antibiotic resistance.