While our cells are performing some important, basic functions, they can generate compounds known as reactive oxygen species (ROS). These include stuff like superoxide and hydrogen peroxide (H2O2). Cells also have ways to deal with ROS. But those processes can also break down; the buildup of ROS can lead to oxidative stress, which can cause serious damage to the cell, and may even lead to cell death. Now scientists have learned more about how cells prevent ROS from getting inside. The findings have been reported in Nature Communications.
“Our cells produce free radicals when we inhale oxygen. Previously, it was thought that the hydrogen peroxide from oxygen could flow freely through ‘doors’ of the cell membrane, i.e. channels that also flux water, but we have shown that the channels in the cell membrane appear to have a protective system,” explained senior study author Karin Lindkvist, a professor at Lund University.
In this study, the researchers used advanced microscopy tools to see that when certain channels are open, molecules like water, glycerol, and hydrogen peroxide can easily get inside. But if hydrogen peroxide levels are too high outside of a cell, hydrogen molecules get stuck at the entry-point of the channel, which closes it and also prevents the cell from being damaged by excessive ROS.
“We were surprised by what we saw. It was like witnessing, in the moment, the cell closing the channel on something that could otherwise cause it harm. Doing that acts as an automatic protection against dangerous levels entering the cell,” said Lindkvist.
This work could also help scientists understand what goes wrong in cells during conditions like cancer or diabetes, when cells are subjected to very stressful conditions.
“Cancer cells, for example, produce extreme quantities of free radicals when they grow quickly. Despite this, they do not die as a result, which suggests that they have ways of getting rid of the excess. One possibility is that they use the same type of channel in the cell membrane to expel the surplus and avoid being suffocated by their own free radicals. In our next study, we want to investigate whether it is possible to kill cancer cells by blocking the channels,” Lindkvist added.
Sources: Lund University, Nature Communications
