|In this image, caveolae are shown merging with the cell membrane (arrow) and floating free inside two cells--Courtesy of the Okinawa Institute of Science and Technology|
The food poisoning bug E. coli, studied by researchers the world over, has revealed another use in biopharma--the potential to produce genetically encoded nanoparticles that could be used to deliver drugs into cells.
Many animal cell surfaces have small pits and inlets in the cell membrane. These are known as caveolae, or "small caves." An international team, including researchers from Japan, Australia, India and Europe, has genetically engineered E. coli using genes for human caveolin, the proteins that form the basis of the caveolae. Normal E. coli do not have these pits on their surface but the engineered bacteria developed them, and these looked identical to the human versions. The bacteria could also be engineered to incorporate targeting proteins on the caveolae membranes.
The caveolae can bud into the membrane and form vesicles or capsules. These capsules, bearing targeting proteins on their surfaces and carrying a drug payload, could be allowed to circulate through the bloodstream and then deliver their contents to the target cell by fusing with its cell membrane.
The researchers' next step will be to find out more about how the caveolae work. Ulf Skoglund of the Okinawa Institute of Science and Technology is optimistic about the potential of this project, but adds: "This is still early, so we don't know whether this is going to be the final delivery form."
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