Chemical breakthrough shields mitochondrial DNA before damage triggers chronic disease
From Alzheimer’s to heart failure, many chronic diseases have been linked to damage in mitochondrial DNA (mtDNA).
Now, scientists at the University of California, Riverside, may have found a way to halt the damage before it begins.
The team has developed a chemical probe that targets damage in mitochondrial DNA (mtDNA), a small but essential genome housed in the cell’s energy-producing structures.
mtDNA is distinct from the DNA housed in the cell nucleus, which holds most of the body’s genetic instructions. Mitochondria, often called the cell’s powerhouses, carry their own smaller set of genes essential for critical functions like energy production.
When mtDNA is harmed by environmental stressors like pollution or toxic chemicals, the cell often degrades it rather than repairing it, leading to inflammation and tissue dysfunction.
Damage meets chemical defense
Instead of attempting to repair the damage, the new molecule steps in earlier, binding to the damaged sites and blocking the enzymes that trigger DNA breakdown.
“There are already pathways in cells that attempt repair,” said Linlin Zhao, UCR associate professor of chemistry, who led the project.
“But degradation happens more frequently than repair due to the redundancy of mtDNA molecules in mitochondria. Our strategy is to stop the loss before it becomes a problem.”
The molecule is engineered with two key components: one that detects and latches onto damaged DNA, and another that ensures it is delivered specifically to mitochondria. That precision ensures nuclear DNA is left untouched while the cell’s powerhouses get protection where it’s needed most.
“I designed the molecule by combining my expertise in chemical synthesis and the Zhao lab’s extensive experience with DNA repair and mitochondria,” said Anal Jana, a postdoctoral fellow in the Zhao lab and leading author of the study.
In lab tests and studies using living cells, the probe significantly reduced the loss of mitochondrial DNA (mtDNA) after exposure to lab-induced damage.
This damage mimicked the effects of toxic chemicals like nitrosamines, common environmental pollutants found in processed foods, water, and cigarette smoke.
Cells treated with the probe maintained higher levels of mtDNA, which could be crucial for sustaining energy production in vulnerable tissues such as the heart and brain.
Powerhouse genome under threat
Loss of mtDNA is increasingly associated with a wide range of diseases, from multi-organ mitochondrial depletion syndromes to chronic inflammatory conditions including diabetes, Alzheimer’s, arthritis, and inflammatory bowel disease.
When mtDNA fragments leak out of mitochondria into the rest of the cell, they can trigger immune responses by acting as distress signals.
“If we can retain the DNA inside the mitochondria, we might be able to prevent those downstream signals that cause inflammation,” Zhao said.
Crucially, the researchers discovered that tagging the DNA chemically did not affect its function.
“We thought adding a bulky chemical might prevent the DNA from working properly,” Zhao said. “But to our surprise, it was still able to support transcription, the process cells use to turn DNA into RNA, and then into proteins. That opens the door for therapeutic applications.”
The project builds on over two years of research into the cellular processes that regulate mitochondrial DNA. While further studies are needed to assess its clinical potential, the new molecule marks a significant shift in how scientists approach DNA preservation under stress.
“This is a chemical approach to prevention, not just repair,” Zhao said. “It’s a new way of thinking about how to defend the genome under stress.”
Source: Interesting Engineering
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Chemical breakthrough shields mitochondrial DNA before damage triggers chronic disease