Some bacteria inject toxins into host cells through syringe-like appendages,media New Atlas reported. Past research has found that we may be able to hijack it as a new drug delivery system. Now scientists from the Max Planck Institute have developed a way to control this mechanism using light.
This appendage, known as the T3SS, is used by certain strains, such as E. coli, salmonella, Shigella, Yersinia and pseudomonas, and is the “worst culprit” for many hospital infections. These bacteria attach to the host cell and push thousands of proteins into the cell via T3SS. These proteins inhibit the host’s defenses, help spread the infection, and cause symptoms such as fever, diarrhea and pain.
There is no denying that this “injection system” is effective. So, of course, scientists are also trying to use it to help more. Just a few months ago, Max Planck’s team reported that they had successfully “hijacked” T3SS and injected useful chemicals such as drugs into cells. But there is still a problem: the system is not very precise. It does not distinguish which cells are injected, but simply emits payloads into any cell that the bacteria happen to encounter.
“As soon as T3SS comes into contact with any host cell, it will immediately emit a payload,” said Andreas Diepold, lead researcher on the study. “This is detrimental to applications in biotechnology or medicine, where we want to target specific cell types, such as in tumor therapy. “
The key to this control is light. Optogenetics is an emerging field that influences certain molecular processes through light pulses at specific wavelengths. In this case, the researchers connected the optogenetic switch to the dynamic “component” of T3SS. The “injection system” can then be turned on and off with a blue light pulse.
They call the resulting system LITESEC-T3SS. In laboratory tests, the team used new technology to inject fluorescent proteins into cancer cells to make them glow blue. Although this was only to check whether the mechanism was working, in another test, the team replaced the payload protein with a protein that induces cell death and released it on cancer cells. Sure enough, it kills tumors effectively.
The researchers plan to continue experimenting with the technology to see what effect it can play. There is still a lot of work to be done before it can become a viable treatment.
The study was published in the journal Nature-Communications.