Worms in space
What can sending tiny worms into space tell us about ageing? And is it significant that they can survive a crash landing back to Earth? Ten years after the Columbia space shuttle burnt up on re-entry into the atmosphere, Ellen Charman speaks to Dr Nate Szewczyk from the MRC/Arthritis Research UK Centre for Musculoskeletal Ageing about putting Caenorhabditis elegans into orbit.
When the space shuttle Columbia disintegrated over Texas in February 2003, tragically killing all seven of its crew, it was expected that the 80 science experiments on board would also be destroyed.
However a week after the accident, five of the six thermos-sized canisters on board — containing petri dishes of C. elegans — were found intact. Close inspection under the microscope revealed that all but one of the canisters contained wriggling worms.
Dr Nate Szewczyk, who was working at NASA at the time, says that these unexpected events yielded important insights.
“It showed that it is possible for multi-celled animals to come through the atmosphere unscathed and is evidence of the spread of life between planets. It also fits with the origin of life concept whereby the very first molecules travelled to earth embedded in meteorites.”
Despite C. elegans having only 959 cells, it is considered a good model for studying human biology because it has similar nerve, muscle and digestive systems. Many of its 20,000 genes perform the same functions as those in humans.
Nate studies the effects of space travel on the functions of these genes, particularly those involved in muscle wasting. Astronauts’ muscles waste away during spaceflight in much the same way as they do as we age and in people with muscle-wasting conditions such as muscular dystrophy.
But counter-intuitively, Nate’s more recent research suggests that even though muscle wastes in space, the process of muscle wasting due to ageing on Earth is faster, because spaceflight suppresses the accumulation of toxic proteins that normally collect in ageing muscle.
He sent his family of worms, which originate from a rubbish dump in Bristol, on the European Space Agency’s Delta Mission in 2004, where they spent 11 days in orbit on board the International Space Station.
He found a group of seven genes that are less active during spaceflight and whose inactivation under laboratory conditions extended the worms’ lifespan. In particular, the worms made less of a molecule involved in insulin signalling, which Nate says is implicated in longer lives.
“This is an interesting discovery as studies on centenarians have shown mutations in their insulin-signalling mechanisms,” he says.
In 2009, the worms, also travelled aboard the space Shuttle Atlantis where they were treated with a technique called RNA interference (RNAi), to regulate the expression of targeted genes. Nate’s team found that this process functions normally in spaceflight and could therefore be used as a therapy to block the function of the proteins that cause astronauts’ muscles to waste in space. This discovery could also help in the treatment of muscle wasting caused by illness and ageing on Earth.
What does the future hold for the worms?
“We are working with colleagues in Japan on two experiments that have been selected for flight and these will continue to look at how the worm adapts to the space flight environment with a focus on ageing and metabolism. Additionally, now that the UK is part of the ESA’s life sciences programme, we’re hoping to get funding for a UK-led experiment,” says Nate.
It is certainly safe to say that these worms have come far from their rubbish-dump origins.
Earlier this month we launched Worm Watch Lab, our citizen science project in which members of the public can help MRC scientists with their research into the nervous systems of the nematode wormCaenorhabditis elegans.