jetPEI was found to be the most efficient transfection reagent tested to express rh-TIMP (tissue inhibitors of Metalloproteinases) in 293E cells (HEK293E). The cells were transfected in the presence of 2.5 % of serum and subsequently grown in serum free medium for 10 days. Protein yields were approx. 30mg/L of media.

The major difficulty for high-throughput screening of therapeutic protein candidates in experimental animal models of pathologies or for structural studies is their fast and efficient production. The tissue inhibitors of metalloproteinases (TIMPs) considered to play a role in many physiological and pathological processes, such as arthritis or cancer, by inhibiting matrix metalloproteinases or acting as signalling molecules, have always been produced with huge difficulties. We hereby propose a new method to overproduce human recombinant TIMP-1 by transient expression in HEK293E cells, followed by a one-step chromatography purification, yielding in only 2 weeks, dozens of milligrams of pure, stable, glycosylated and active protein for in vitro and in vivo studies. This easy to set up, rapid, and efficient method could be applied for any naturally secreted mammalian protein.