In a groundbreaking study led by researchers at the University of California, Irvine, and the University of Pennsylvania, the inner workings of mitochondria, the cellular powerhouses, were observed for the first time using new super-resolution microscopes. Mitochondria play a crucial role in human health by generating adenosine triphosphate (ATP), an organic compound that fuels various cellular processes through aerobic respiration.
While past research primarily focused on the physical characteristics of mitochondria within living cells, this project marked a significant advancement by employing super-resolution microscopes to study live, extracellular mitochondria. The researchers, utilizing all three leading super-resolution methods, including Airy microscopy, stimulated emission depletion microscopy, and lattice-structured illumination microscopy, observed changes in mitochondrial membranes under different metabolic states, providing insights into the electrophysiological functioning of these vital cellular organelles. The findings were published in the journal ACS Nano.
Co-author Peter Burke, UCI professor of electrical engineering and computer science, highlighted the significance of the study: “Now we can control each individual electrical component and cause it to charge and discharge.” This capability was facilitated by the latest generation of super-resolution microscopes.
The researchers focused on cristae, intricate structures within mitochondria measuring approximately 100 nanometers. The use of super-resolution microscopes allowed them to probe the voltage distribution in structures smaller than the shortest wavelength of visible light, necessitating powerful instruments for this investigation.
Burke drew an analogy to studying the battery pack in a Tesla: “Imagine trying to study how the battery pack in a Tesla works, but you can only do it by driving the car. You would not learn much about the battery pack inside the car.”
By extracting mitochondria from cells and maintaining their viability, the researchers were able to charge and discharge them, observing how each component functioned as an individual battery. The study revealed that mitochondrial batteries rearrange themselves during these processes, a unique feature not observed in conventional batteries.
Contrary to past assumptions derived from studying frozen mitochondria, the experiments demonstrated that the internal structure of mitochondria dynamically changes based on the cell's metabolic needs. Mitochondria can create and dismantle their “batteries” (cristae) as required, showcasing their adaptability to cellular energy demands.
Peter Burke emphasized the potential applications of this research in human health, particularly in understanding the cellular aging process. “Once we understand how they create energy, we can start to think of ways to modify this for improving human health and longevity,” he stated, underlining the broader implications of unraveling the intricacies of mitochondrial function.
Source: University of California, Irvine