All animals, including humans, experience stress. Not the type where you worry about paying bills, but metabolic stress - triggered by starvation, obesity or bacterial infections.
When we are in a biologically stressed state, protective responses occur in mitochondria, which produce energy in every one of our cells, to cope with the stress and provide energy needed to survive. When mitochondria are overwhelmed by stress, they are unable to produce enough energy for cells to survive and the body starts to shut down.
Professor Roger Pocock, from Monash University's Biomedicine Discovery Institute, has been studying two neurons in the brain of a microscopic worm, Caenorhabditis elegans, for almost two decades, because - perhaps surprisingly - it has a very similar genome to humans.
His team's latest study, published in the journal PNAS, reveals a mechanism in Caenorhabditis elegans where environmental sensing by just two neurons enables these animals to 'predict' and 'prime' the systemic mitochondrial stress response.
According to Professor Pocock, this is one of few studies to reveal that environmental sensing can trigger a mitochondrial protective response throughout the body. Thus, sensing external cues (e.g. food and toxins) may predict when metabolic stress will occur and prepare the organism to combat resulting metabolic challenges.
Stress causes inappropriate folding of proteins within mitochondria, which hampers their energy production - the first step in a cascade that leads to the biological consequences of metabolic stress, such as chronic inflammation and insulin resistance.
The two worm brain neurons that Professor Pocock and his team have been studying sense levels of carbon dioxide and oxygen in the environment. According to Professor Pocock, when these neurons, which have functional similarities to carotid bodies in humans, are no longer able to sense the presence of CO2, mitochondria throughout the body are triggered to "expect" and respond to stressful situations.
"Knowing that there are neurons in this nematode that perform the same function in humans - that can literally predict and protect against metabolic stress - has the potential for the development of drugs that can also protect against metabolic stress," he said.
