Michael Rosbash: "Circadian rhythms may be the physiological piece least affected by climate change"
It all started with the discovery in the fruit fly (Drosophila melanogaster) of a gene (period) that encodes a protein (PER) that accumulates during the night and is degraded during the day.
It continued with the discovery of a second clock gene, timeless, and culminated with the complete description of the molecular mechanisms that control the circadian rhythms that allow the adaptation of living beings to their environment.
This is the so-called internal clock with which plants and animals – including humans – synchronize their biological rhythm with the rotation of the Earth.. The scientists who unraveled this circadian machinery Michael Rosbash, Jeffrey Hall and Michael Young received the Nobel Prize in Medicine in 2017.
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The environment in which human beings operate is undergoing profound transformations due to climate change.. Rosbash, who has just visited Spain within the framework of the global Nobel Prize Inspiration Initiative and with the help of the AstraZeneca Foundation, commented in an interview with Diario Médico that it is very possible that these changes exert some influence. However, he points out, “circadian rhythms are quite invariable or insensitive to temperature; they are constituted in a different way.”
Hence, “paradoxically, they could be the physiological piece least affected by climate change”. The oscillations between lightness and darkness do influence the internal clock, but it must be taken into account that light “is not going to change too much due to climate change.”
The geneticist details the three findings that were most surprising to him in his research on circadian mechanisms. “First of all, I was surprised that the genes and genetic foundations of the fruit fly are so well conserved in mammals, including humans”. Another unexpected discovery was “how large a proportion of gene expression is under circadian control.”
Finally, he was shocked by the number of tissues it covers. “At first we thought it might be restricted to a very small fraction of cells and tissues in animals, but it is widespread”. In summary, these are very generalized mechanisms from a genetic and functional point of view that are also conserved throughout evolution.
Far beyond the brain and sleep
When talking about the scope of circadian mechanisms, sleep and the brain are often cited as examples, but their physiological and anatomical scope is much greater, to the point that it can be said to be global.
All Olympic records have been made in the late afternoon, because that is when maximum physiological performance can occur
“It includes many aspects of physiology, such as daily hormonal fluctuations of all kinds,” says Rosbash.. The Nobel Prize provides definitive proof of this ubiquitous influence: “All the Olympic records have been made in the late afternoon, because that is when maximum physiological performance can take place.”. In short, practically everything you can imagine is under that physiological control, without forgetting the libido.
The same can be said of the tissues: liver, kidney, muscle, spleen, skin, pancreas, lung…. “The little timekeeper is in absolutely all tissues,” summarizes the Nobel Prize in Medicine.
Circadian mechanisms and human health
Once the molecular mechanisms that allow humans to adapt to the Earth's rotation that mark the light cycles that, in turn, determine the periods of sleep and wakefulness and other physiological functions have been revealed, it is worth asking how the disease affects human health. operation of all that machinery. Rosbash acknowledges that, at the moment, it remains largely uncharted territory, although he is convinced that there must be a relationship.
Everything seems to indicate that those who have certain problems related to their circadian clock are destined to get sick, but it is still not known for sure to what extent.. “There are surely people who have mutations that make their clocks go too fast or too slow,” says the geneticist.. Now, do these individuals have a shorter lifespan or suffer from cancer more frequently? “I don't know,” he replies.. “It is known that there is a relationship with aspects such as cancer, but it is not very direct and its true impact is unknown.”
Challenges of genetics
Something similar happens with genetic research, which has advanced spectacularly but still has many pending challenges.. It is known that the tentacles of genetics are very long because it affects all areas of life.
“Human genetics has experienced a revolution in the last 10 years that has impacted all areas,” highlights Rosbash.. Aberrant clock genes have been proven to cause health problems, but “the extent to which they are impaired is not known, and in some cases it remains a mystery how a particular mutation is connected to a particular disease.”