Summary: A new study of Drosophila reveals a link between circadian rhythms, diet, life expectancy and eye health. Suddenly, researchers discovered processes that triggered the aging process in the eyes of flies.
A source: Garden Institute
Researchers at the Garden Institute were the first to show in Drosophila the link between diet, circadian rhythms, eye health and life expectancy.
Published in the June 7, 2022 issue Nature Communicationsthey additionally and suddenly found that the processes in the fly’s eye were activating the aging process.
Previous research has shown that there is a link between eye diseases and poor health in humans.
“Our study suggests that this is not a correlation: eye dysfunction can cause problems in other tissues,” said Pankaj Kapahi, a senior author and professor at the Buck Institute, whose laboratory has proven calorie restriction by fasting for many years. Many functions of the body can be improved.
“We are now showing that fasting not only improves eyesight, but also plays a role in affecting life expectancy.”
Dr. Brian Hodge, PhD, the lead author of postdoctoral research at Kapahi’s laboratory, said: “It was a surprise to us that the eye itself at least directly regulates the life of fruit flies.
The explanation for this connection, Hodge said, lies in the circadian “clocks” in the molecular mechanism within each cell of each organism, which have evolved to adapt to daily stresses, such as changes in light and temperature. the day.
These 24-hour oscillations — circadian rhythms — affect complex animal behavior, such as predatory interactions and sleep / wake cycles, to the temporary regulation of gene transcription and protein transfer molecular functions.
In 2016, Kapahi’s laboratory published a study Cell metabolism shows that there have been significant changes in their circadian rhythms along with prolonging the life of fruit flies in a restricted diet.
When Hodge joined the lab later that year, he wanted to dig deeper to understand which circadian functions improved with dietary changes and which required circadian processes for longevity observed with dietary restrictions.
Hodge, a scientist at Fountain Therapeutics in South San Francisco, said: “The lifespan of a fruit fly is so short that it’s a beautiful model that allows you to screen many things at once.”
The study began with a detailed survey to see which genes oscillate in a circadian fashion, compared to flies on an unrestricted diet and those who ate only 10 percent of the protein on an unrestricted diet.
Hodge immediately noticed many genes that responded to the diet, as well as showing up or down at different time points or “rhythmically.”
He then found that the most activated rhythmic genes with food restriction appeared to come from the eye, especially photoreceptors, and specialized neurons located in the retina that respond to light.
This finding led to a series of experiments aimed at understanding how diet restriction could prolong life. For example, experiments have shown that keeping flies in constant darkness prolongs their life.
“It seemed very strange to us,” Hodge said. “We thought flies needed light signals to be rhythmic or circadian.”
Then, using bioinformatics: Do genes that respond to eye rhythm and dietary restriction affect life expectancy? The answer is yes, they do.
“We always think of the eye as something that serves us and provides vision. We don’t think it’s something that needs to be protected to protect the whole body, ”said Kapahi, an associate professor of urology at UCSF.
Because the eyes affect the outside world, he explained, there is a critical immune defense, which can lead to inflammation, and when it is present for a long time, it can cause or worsen any common chronic disease.
In addition, light itself can cause photoreceptor degeneration, which can lead to inflammation.
“Staring at computer and phone screens and being exposed to light pollution at night are very dangerous conditions for circadian clocks,” Kapahi said.
“It destroys the protection of the eye and it can lead to non-visual consequences, damaging the rest of the body and the brain.”
There is much to understand about the role of the eye in the overall health and longevity of the body, including how the eye regulates life expectancy and whether the same effect applies to other organisms.
The biggest question in this paper, which may apply to humans, is whether mammalian photoreceptors affect longevity?
Probably not as much as fruit flies, ”said Hodge.
But since photoreceptors are just specialized neurons, he said, “The stronger connection I’m arguing is the role that circadian function will play in neurons in general, especially dietary restrictions and how they can be used to maintain neural function in old age.”
Once researchers understand how these processes work, they will start targeting the molecular clock to slow down aging, Hodge said, adding that humans can help maintain vision by activating the clocks in our eyes. “It could be through diet, medication, lifestyle changes … There’s a lot of exciting research ahead,” he said.
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Author: Press service
A source: Garden Institute
The connection: Press Service – Garden Institute
Photo: Image in public domain
Original study: Open access.
Brian Hodge Nature Communications
Dietary restriction and transcription factor clock delay eye aging to prolong life in Drosophila
Many important processes in the eye are under circadian regulation, and circadian dysfunction has been shown to be a potential driver of eye aging. Dietary restriction is one of the most powerful life-prolonging therapies and increases circadian rhythms with age.
Here, we show that dietary restriction prolongs life Drosophila melanogaster By promoting circadian homeostatic processes that protect the visual system from age and light-related damage.
Altering the transcription factor of the main molecular clock of the right leg, the clock or clock-release genes, accelerates visual aging, creates a systemic immune response and shortens life.
Diet-restricted flies are protected from the short-lived effects of photoreceptor activation. In contrast, inactivation of photoreceptors by rhodopsin mutations or by keeping flies in constant darkness primarily prolongs the life of flies fed a nutritious diet.
Our findings define the eye as a dietary-sensitive modulator of life expectancy and show that vision is an antagonistic pleiotropic process that contributes to the aging of the body.