Release of CD36-associated cell-free mitochondrial DNA and RNA as a hallmark of space environment response

This research explores how space travel affects our body's cells, specifically looking at tiny particles called extracellular vesicles or EVs. These microscopic bubbles carry important messages from one cell to another and can tell us a lot about what is happening inside the body during stressful situations like being in outer space for an extended period of time. The study found that when mice were sent on a simulated trip around Earth, some changes occurred within their cells related to energy production (which happens mostly in tiny structures called mitochondria). The researchers noticed more genetic material from these powerhouses inside the EVs compared to normal conditions. However, they couldn't be sure if this was because it came directly from damaged or stressed out mitochondria within cells themselves, or whether some of that material had been released into the bloodstream and then picked up by the EVs before being sent back inside our bodies again.

In this research, sophisticated plasma and extracellular vesicle (EV)-fractionation techniques coupled with electron microscopy were employed to investigate the presence of cell-free mitochondrial RNAs (cfRNA) in blood samples from mice subjected to a simulated spaceflight environment, as part of an experiment conducted by JAXA. The study aimed at understanding how exposure to microgravity affects gene expression related to mitochondrial function and the potential release mechanisms for cfRNA outside cells under stress conditions in space. The methodology involved isolating EVs from blood samples of mice before, during, and after their flight on a parabolic aircraft designed to simulate microgravity (2016 JAXA mission). The researchers then used electron microscopy for detailed visualization of the isolated vesicles. However, despite these advanced techniques, there was no substantial evidence provided in this study that cfRNA outside mitochondria is present within EVs or plasma following spaceflight-induced stress conditions on Earth's surface gravity levels (lines 340-357).