Mitochondrial Starvation Triggered by Excess Cellular RNA Accumulation
In a study published in PNAS, researchers from Texas A&M University revealed that an abundance of RNA inside human cells can directly damage mitochondria and restrict their energy production.
Cellular Energy Disruptions Caused by Messenger RNA Overload
Cells typically maintain a strict equilibrium between RNA production and degradation to manage protein synthesis and clear out defective genetic material. However, invading viruses, aging, certain cancers, and neurodegenerative disorders can upset this balance. “MRNA is a normal component of our cells, but it seems like with many good things, if we get too much, that can become a problem for the cell,” stated virologist Zhilong Yang from the College of Veterinary Medicine and Biomedical Sciences at Texas A&M University. “What surprised us was finding out that too much mRNA — something cells normally need every day — can also damage mitochondria and interfere with the cell’s ability to produce energy.” “Scientists have long known that RNA degradation helps control protein production and remove defective RNA,” Yang said, adding that “Our study reveals another important role: It helps cells maintain the energy they need to function properly.” “The virus needs to keep RNA levels balanced inside the cell.”
Isolating Mitochondrial Damage Without Immune Activation
The research team cultured human cells in the laboratory and introduced a vaccinia virus alongside direct RNA transfers to drive molecular accumulation. Oxygen consumption measurements served as a proxy for mitochondrial health. When researchers isolated mitochondria and directly added RNA to them, the organelles still suffered functional damage. Djamal Brahim Belhaouari noted that observing mitochondrial harm in isolated samples proved this was a previously unknown cellular response to RNA rather than a secondary effect of an immune flare-up. Excess RNA correlated with lower oxygen use and reduced energy output across the tested cells. Further experiments involved direct RNA transfers without infection, including mRNA and double-stranded RNA, with the inclusion of mRNA suggesting that too much of these molecules in general is not good for cells. “Too much double-stranded RNA or mRNA that cannot be degraded effectively may contribute to disease processes in some contexts.”
Implications for Future Therapeutics and Vaccines
The discovery offers a fresh perspective on optimizing RNA-based therapeutics and vaccines, which introduce genetic instructions into cells to prompt specific protein production. Understanding how excess RNA burdens mitochondria could improve the safety profile of these treatments and clarify mechanisms behind viral infections and age-related deterioration. “We think the negatively charged RNA may accumulate around mitochondria and disrupt the electrical balance needed for energy production, although how it happens is unknown,” Yang explained regarding the ongoing investigation into the exact cellular pathways involved. “This is a new concept that we are continuing to explore.”
