Violet light selectively switches on drugs in tiny groups of cells

Delivering drugs in a way that sees them target only the cells that need treating is a common objective for scientists in many areas of medical research, from cancer, to arthritis, to obesity. A breakthrough from an international team of researchers raises hopes of a new, targeted approach to regenerative medicine, with the team demonstrating how violet light can be used to switch on a new drug in tiny groups of cells to promote growth in highly selective areas.

The research was carried out by scientists at Germany’s Friedrich Schiller University Jena and Ludwig-Maximilians University, who worked with researchers at New York University to explore new possibilities in the field of photopharmacology. This refers to the notion of turning drugs on and off through light exposure, with the team looking to leverage a key structural protein in the cells called actin for their purposes.

“Up to now, there are no drugs available that target actin, because the protein is found everywhere in the body, for example in large quantities in the muscles,” explains Prof. Hans-Dieter Arndt of Friedrich Schiller University Jena. “Such a substance would therefore have little to no targeted effect. However, our new compounds only exert activity on actin in areas where cells are exposed to the appropriate light.”

The team achieved this impressive breakthrough by first synthesizing a drug that naturally causes actin to stiffen. Experimenting with this molecule in the lab led the team to come up with a variation that changed its structure when exposed to violet light, in turn increasing its stabilizing effects on the cells. This version of the molecule could then be returned to its natural structure and form through exposure to green light.

In further experiments in the lab, the team demonstrated how the molecule could be absorbed by cells, with violet light exposure then used to precisely control the viability and mobility of those cells, along with how they communicate with the cytoskeleton, the structure that helps cells maintain their shape and organization.

The team says this technique can be used to selectively control target individual cells with accuracy of as little as 10 micrometers. The new drug, which they’ve called Optojasp, could be harnessed to treat a variety of conditions relating to regenerative medicine.

“It is possible that this method could be used in the future to treat diseases of the eye or on the skin, i.e. of organs that can easily be exposed to light,” says Arndt. “This technique could also be of interest in the field of neuroregeneration. The aim here is often to encourage certain nerve cells to grow in preference to others.”

The research was published in The Journal of the American Chemical Society.

Source: Friedrich Schiller University Jena

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