New research in worms has demonstrated how prolonged exposure to low gravity can alter cells at the genetic level.
Humans, and other living organisms, have evolved to function optimally at the gravity level we experience on Earth. Low gravity experienced during extended spaceflight causes health decline in astronauts, having physiological effects on the heart, immune and nervous system among many others. This is a major obstacle to space travel, and so finding therapeutic targets to maintain good health in space is key to accelerate safe human space travel and habitation.
'We looked at levels of every gene in the worms' genome and identified a clear pattern of genetic change' said Dr Timothy Etheridge, of the University of Exeter, 'these changes might help explain why the body reacts badly to space flight'.
The identification of therapeutic targets was the aim of scientists at the University of Exeter and the NASA GeneLab, who carried out a genetic analysis of Caenorhabditis elegans (C. elegans) worms living at low gravity in the International Space Station. When compared to worms that were subject to high gravity in a centrifuge, a subtle change in gene expression was found in about 1000 genes. The most significant changes in expression were seen in genes involved in cell metabolism and neuronal function.
It is important to discern, gravity does not alter the fundamental DNA of the C. elegans, merely which genes are expressed into functional molecules in the cell.
These results may explain the negative impact gravity has on living organisms and preventing these changes using targeted therapies may reduce health effects.
C. elegans are a commonly used biological model for genetic experiments, favoured for their simplicity. The worm's body is made up of only 1000 cells so scientists can measure gene expression in every cell type. Despite the many differences, worms can still tell us a lot about human genetics, as many genes are shared between the two species.
'These worms display molecular signatures and physiological features that closely mirror those observed in humans,' Craig Willis, lead author of the study published in iScience, said, 'so our findings should provide foundations for a better understanding of spaceflight-induced health decline in mammals and, eventually, humans.'