According to a study by the University of Michigan, a high-sugar diet reprograms the taste cells in fruit flies, weakens their sensitivity to sugar, and leaves a “molecular memory”
Researchers Monica Dus, Anoumid Vaziri and their collaborators found when studying fruit flies that a high-sugar diet completely reshaped the flies’ taste cells, even if When fruit flies change back to a healthy diet, their molecular memory will continue. The molecular memory of previous diets may cause animals to fall into unhealthy eating habits.Their findings are published in Scientific progress.
UM professor of molecular cytology Dus said: “When we eat food, it only takes a few mouthfuls to disappear. We didn’t really think it could have such a lasting effect on our brain.” And developmental biology and the research The senior author. “But when animals are moved to a different food environment (such as a healthy diet), they retain the molecular memory of a high-sugar diet in the cell. This suggests that the past food environment may affect the animal’s future behavior.”
In particular, the researchers discovered that a high-sugar diet reprograms cells located in the mouth of fruit flies, and these cells feel sweet, causing them to malfunction. This reprogramming involves an epigenetic regulatory factor called Polycomb Repressive Complex 2.1 or PRC2. Epigenetic regulators are a group of enzymes that can affect gene expression and expression by remodeling chromatin. Chromatin includes chromosomal material in everything from plants to humans.
In this case, the research team discovered the way PRC2 is distributed in the chromatin of neurons, and when fruit flies eat a high-sugar diet, they feel a change in sweetness. They found that this change activated some genes and silenced others, especially genes involved in sweetness testing.
Vaziri, a doctoral student in the Das lab, said: “So, through this very special way, a high-sugar diet can silence the genes needed for sweetness.” “What’s more interesting is the role of gene silencing. It is actually long-lasting, so even if the animal is removed from the high-sugar diet, the genes related to taste will still change, and the animal will still experience sweet taste defects.”
There are only about 60 sweet cells in the mouth of fruit flies. After purifying these taste cells from diet-controlled flies and high-sugar flies for a week, the researchers used two techniques to identify the silenced genes. One of these techniques involves isolating ribosomes (particles that bind RNA to synthesize proteins) from these 60 cells and sequencing the messenger RNA associated with them to determine whether genes have been silenced. Messenger RNA is a form of RNA that can carry genetic instructions from DNA to ribosomes.
On the seventh day of the high-sugar diet, Vaziri found that more than 80% of the sweetness genes were silenced. This is because PRC2 changes its binding to DNA and therefore changes the “program/software” that taste cells run. The new procedure did not make them respond well to sweetness and almost reprogrammed their identity as sweetness cells.
“We not only have to consider food, then eat it, and then pass on its effects, but we should actually treat it as an experience that may affect our future behavior and food choices, similar to the trauma of early life on the adult brain. Lasting impact, Vaziri said.
To confirm that PRC2 is behind gene silencing, the researchers mutated the complex to see if they can restore normal gene expression in the cell. By mutating the complex, they found that fruit flies did not have a decreased ability to perceive sweetness.
Interestingly, fruit flies that can still taste sugar can also maintain lean meat. The fruit flies that do feel the decrease in sweetness become obese. The reason for this is due to Dus Lab’s previous research on how sugar interferes with satiety signals. When fruit flies are less able to taste sugar, they will eat more and more sugar to achieve the same feeling of fullness. When their ability to taste sugar is not diminished, they will end the diet sooner.
Duss said: “They didn’t eat a whole biscuit, but stopped at two points.” “This really reinforces the notion that these changes in taste are essential to our ability to control food choices and food intake. ”
A high-sugar diet inhibits the release of dopamine and triggers overeating
A. Vaziri et al., “Permanent epigenetic reprogramming of sweetness through diet”, Scientific progress (2020). advances.sciencemag.org/lookup….1126 / sciadv.abc8492
Provided by the University of Michigan
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