CO2 is actually good for our DNA, even though it's wreaking havoc on Earth's climate

The cells in our bodies function like bustling cities. They run on an iron-powered system that uses hydrogen peroxide, not merely as a cleaning agent, but as a conduit for crucial signals that involve carbon dioxide (CO₂) and help protect the DNA.

It’s an efficient system under normal circumstances, but becomes a cause for concern when cells experience stress, such as during inflammation or a sudden surge in energy usage.

Under such strain, oxidative stress can inflict damage to cells at the genetic level.

Role of bicarbonate

There is a chemical reaction within our cells that goes by the name of the Fenton reaction. In this reaction, iron and hydrogen peroxide mix, producing destructive hydroxyl radicals that indiscriminately attack DNA and RNA.

However, these cells manage to turn what seems to be an adversary — CO₂ — into an ally.

Carbon dioxide, infamous for its impact on global climate, provides our DNA and cells with bicarbonate, which helps maintain pH balance.

Bicarbonate’s overlooked function

According to a study conducted by a team of chemists from the University of Utah, bicarbonate’s function extends beyond being a simple pH buffer.

The research showed that bicarbonate can alter the Fenton reaction in our cells, thereby reducing the formation of chaotic hydroxyl radicals. Instead, the reaction produces carbonate radicals which pose a lesser threat to DNA.

Oxidative stress and diseases

Cynthia Burrows, a distinguished professor of chemistry, and senior author of the study, talked about the implications of this discovery, particularly in understanding diseases where oxidative stress plays a substantial role.

“So many diseases, so many conditions have oxidative stress as a component of disease. That would include many cancers, effectively all age-related diseases, a lot of neurological diseases,” said Burrows.

“We’re trying to understand cells’ fundamental chemistry under oxidative stress. We have learned something about the protective effect of CO₂ that I think is really profound.”

Burrows’ team included research associate professor, Aaron Fleming, and doctoral candidate, Justin Dingman, both of whom are members of the Burrows Laboratory.

Real impact of CO₂ on DNA

Through their study, the researchers discerned the significant role of bicarbonate in our cells when they are confronted with oxidative stress.

Without bicarbonate, or CO₂ being present during DNA oxidation reactions, the free radical species generated – the hydroxyl radical – is extremely reactive and severely damages DNA.

However, the presence of bicarbonate from dissolved CO₂ changes the reaction, resulting in a less damaging radical that targets only guanine, a constituent of our genetic code.

Bicarbonate, the new game-changer

The discovery by Burrows and her team suggests that cells are far more intelligent than previously believed.

This could reshape our understanding of oxidative stress and its link to diseases, such as cancer, and aging.

More importantly, their findings suggest that many scientists studying cell damage might have been conducting lab experiments in ways that don’t reflect real conditions, which could cast doubt on their findings.

Question of proper lab conditions

Scientists grow cells in a tissue culture in an incubator set to body temperature, where carbon dioxide levels are raised to 5%.

This environment replicates the cells’ natural habitat as they metabolize nutrients. However, this environment changes when researchers begin their experiments outside the incubator.

Importance of CO₂ beyond DNA

According to Burrows, bicarbonate must be included in experiments to ensure reliable results.

“Most people leave out bicarbonate/CO₂ when studying DNA oxidation because it is difficult to deal with the constant outgassing of CO₂,” Burrows explained.

“These studies suggest that to get an accurate picture of DNA damage that occurs from normal cellular processes like metabolism, researchers need to be careful to mimic the proper conditions of the cell and add bicarbonate, i.e., baking powder!”

Potential positive outcomes

Burrows conjectures that her study could have unexpected benefits that may someday advance research in other areas.

Her lab is currently seeking new funding from NASA to study the effect of CO₂ on people confined to enclosed spaces, such as those inside space capsules and submarines.

CO₂‘s protective properties on DNA

Research into the protective effect of CO₂ could be vital for astronauts working in enclosed environments where elevated CO₂ levels are commonplace.

A slightly higher concentration of CO₂ might offer a protective shield against radiation, which generates hydroxyl radicals. Such findings could drastically change the way we look at carbon dioxide and its role within our cells.

Ultimately, this study sheds light on how cells smartly defend DNA and maintain balance. The discovery of bicarbonate’s role in this process is bound to stir the realms of scientific research, shattering misconceptions and reshaping future studies.

The research was funded by the NIH/National Institute of General Medical Sciences.

The study is published in the journal Proceedings of the National Academy of Sciences and BioRxiv.

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