A recent study published in the journal Nature Aging demonstrates that genetically modified mitochondria can transform light energy into chemical energy that cells can utilize, eventually prolonging the lifespan of the roundworm C. elegans. The findings give information on important pathways in the aging process, even if the idea of sunlight-charged cells in people is more science fiction than reality.
The study’s principal author, Andrew Wojtovich, Ph.D., associate professor of anesthesiology and perioperative medicine, as well as of pharmacology & physiology at the University of Rochester Medical Center said they know that mitochondrial failure is a result of aging.
According to this study, laboratory worms had longer, better lives just by having their metabolism increased by light-powered mitochondria. The researchers can now investigate mitochondria in greater detail and develop fresh approaches to age better and treat disorders associated with aging thanks to these discoveries and new research tools.
Most of the cells in the body have mitochondria, which are organelles. Adenosine triphosphate (ATP), the substance that supplies energy for vital cell processes like muscular contraction and the electrical impulses that aid nerve cells in communicating with one another, is produced by mitochondria, often known as cellular power plants, using glucose.
The exchange of protons across a membrane separating various compartments of mitochondria, which ultimately forms a mechanism known as membrane potential, allows for a variety of processes that lead to the production of ATP. It has been revealed that membrane potential decreases with aging, perhaps contributing to a range of age-related illnesses, including neurodegenerative disorders.
The new study utilized a tiny roundworm called C. elegans, which, like the fruit fly Drosophila, has long been a research tool used by scientists to understand fundamental biological concepts that, in many cases, hold true for the whole animal world.
An existing study method that allowed the researchers to control mitochondrial activity was modified by a team of scientists from the United States and Germany. The method, known as optogenetics, has long been used to target and activate certain neurons, allowing researchers to more thoroughly investigate patterns of brain activity.
In a 2020 study published in the journal EMBO Reports, the scientists first detailed how they genetically modified C. elegans mitochondria to integrate a light-activated proton pump derived from a fungus.
In the current study, the proton pumps would transfer charged ions across the membrane when exposed to light, harnessing the light’s energy to charge the mitochondria. The roundworms’ lifespan was extended by 30–40% as a result of this procedure, which the researchers called mitochondria-ON (mtON). It also enhanced the synthesis of ATP and membrane potential.
The initial author of both papers is Brandon Berry, Ph.D., a post-doctoral fellow at the University of Washington who obtained his doctorate in physiology from the University of Rochester. In that they burn a carbon source, typically glucose, to provide usable energy for the cell, Berry compared mitochondria to industrial power plants.
What the researchers have done is connect a solar panel to the infrastructure of an existing power plant. The optogenetic device mtON in this case is the solar panel. Then, in addition to the regular combustion route, the usual mitochondrial machinery is capable of using the light energy to produce ATP.
The finding is significant because it gives researchers additional understanding of the complex biological functions that mitochondria perform within the human body, a subject that science is only just beginning to comprehend. The study also develops a novel technique for manipulating and researching mitochondria in a living cell’s environment. This could be a useful setting for studying mitochondria and figuring out how to get involved and support function.
Berry stated that further research is needed to fully grasp how mitochondria function in animals. Initially, in worms, as in the current work, but also in cultured human cells and in mice. Future studies will be well-prepared to focus on the most likely contributors to human illness and aging as a result.
Berry, B.J., Vodičková, A., Müller-Eigner, A. et al. Optogenetic rejuvenation of mitochondrial membrane potential extends C. elegans lifespan. Nat Aging (2022). https://doi.org/10.1038/s43587-022-00340-7
Solar-powered cells: Light-activated proton pumps generate cellular energy, extend life (phys.org)