Enhancing transient protein expression in HEK-293 cells by briefly exposing the culture to DMSO

Background: Transient expression of proteins in mammalian cells is a key technique for many functional and structural studies of human and higher eukaryotic genes as well as for the production of recombinant protein therapeutics. Maximizing the expression efficiency to achieve a higher expression yield is desirable and may be even critical when, for instance, an expressed protein must be characterized at the single-cell level. New Methods: Our goal was to develop a simple method by which protein expression yield in human embryonic kidney (HEK)-293 cells could be enhanced with a brief treatment of dimethyl sulfoxide (DMSO) solution. Results: By expressing green fluorescent protein (GFP) as a reporter protein using the calcium phosphate transfection method and imaging a large population of cells, we found that a 5-min exposure of 10 % DMSO to HEK-293 cells, 4 h after transfection of the protein of interest, leads to similar to 1.6-fold increase in the expression yield without causing any appreciable cytotoxicity. By expressing an alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and separately a kainate receptor in HEK-293 cells and measuring glutamate-induced whole-cell current response, we also found that such a brief DMSO treatment did not affect channel activity. Conclusion: This method is simple, efficient and inexpensive to use for enhancing transient transfection yield in HEK-293 cells.

Automated summary

This study developed a simple, efficient, and cost-effective method to enhance protein expression yield in HEK-293 cells through a brief treatment of DMSO solution. The method proved to increase expression yield without affecting cell viability, making it a valuable tool for transient transfection studies.