In the study of the Drosophila fly, NIH scientists found that only about 30% of the genes responsible for aging can reset the animals’ internal clocks. The rest may reflect the body’s response to the bacteria. Above is a picture of the intestines of a whitefly. which is an important source of bacteria. Credit: Courtesy of Giniger lab NIH/NINDS
NIH scientists discovered that bacteria may activate older genes in flies.
To better understand the role bacteria play in health and disease, researchers at the National Institutes of Health have administered antibiotics to fruit flies. and examined the lifelong activity of hundreds of genes that scientists previously thought could control aging. Antibiotics don’t just prolong the lives of flies. but also dramatically alter the activity of these genes. Their findings suggest that only about 30% of age-related genes determine the animals’ internal clocks, while the rest reflect the body’s response to bacteria.
“For decades, scientists have developed aging genes. These genes are thought to regulate the aging process throughout the animal kingdom. From worms to mice to humans The study authors published in iScience“We were shocked to find that only 30% of these genes may be directly related to the aging process. We hope these results will help medical researchers better understand the powers underlying various age-related disorders.”
The results were accidental. Dr. Giniger’s team studied the genetics of aging in a blackberry fly called the whitefly. Previously, the team had shown that the hyperactive immune system may play a key role in the damage. However, the study did not examine the role of bacteria in this process.
to test this idea They fed the newly born male flies with antibiotics to prevent bacterial growth. At first they thought the antibiotic would have little or no effect. But when they look at the results They saw something interesting. Antibiotics prolong the life of flies by approximately 6 days, from 57 days for the control flies to 63 days for the treated flies.
“This is a huge leap forward for flies. In humans, it is equivalent to obtaining about 20 years of life,” said Arvind Kumar Shukla, Ph.D., a postdoctoral fellow in Dr. Giniger’s team and the study’s lead author. “We were caught unexpectedly. And it makes us wonder why these flies have been dead for so long.”
Dr. Shukla and his colleagues look for clues in the fly genes. Specifically, they used advanced genetic techniques to track gene activity in the 10, 30 and 45 day old flies’ heads in a previous study. Research teams have discovered a link between the age of the flies and the activity of several genes. in this study They found that feeding the flies with antibiotics destroyed many of these links.
Overall, the gene activity of antibiotic-treated flies changed very little with age. regardless of their actual age The flies treated appeared to look like 30-day-old control flies. They appeared to be caused by flat lines in the activity of about 70% of the genes the researchers surveyed. which most thought to control aging
“In the beginning we had a hard time believing the results. Many of these genes are classic hallmarks of aging. But our results suggest that the activity of these genes is a function of the bacterial appearance rather than the aging process,” said Dr. Shukla.
especially This includes genes that regulate stress and immunity. Researchers tested the effects that antibiotics have on these genes by starving the flies or infecting harmful bacteria. and did not find a clear trend at a certain age Antibiotics help flies survive starvation or infection longer than usual. while the drug at other ages It does not affect or reduce the chances of survival.
Further experiments supported the results. For example, researchers saw similar results in gene activity when they prevented bacterial growth by raising the flies in a completely sterile environment without antibiotics. They also saw similar trends when they analyzed new data from another study that fed the flies with antibiotics. Again, antibiotics have ruled out many links between gene activity, age and dominant traits.
Finally, the researchers found an explanation for why the antibiotics prolong the life of the flies in the remaining 30% of the genes they analyzed. In conclusion, the rate at which the activity of these genes changed with age was slower than normal in the flies treated. antibiotic
interesting is Many of these genes regulate the sleep and wake cycle. smell detection and maintenance of the exoskeleton or the shell that envelops the flies Sleep-wake cycle experiments have supported a link between these genes and aging. The activity of waking flies decreases with age. And this trend is improved by treating the flies with antibiotics.
“We found that some genes are actually responsible for the body’s internal clock,” said Dr. Jiniger. “In the future, we plan to find out which genes are actually linked to the aging process. If we want to fight aging We have to know exactly which genes are responsible for the clock.”
Reference: “Common Characteristics of Aging Failure to Occur in Drosophila Fed Without a Bacterial Microbiome” by Arvind Kumar Shukla, Kory Johnson and Edward Giniger, 24 June 2021, Available here. iScience.
doi: 10.1016/j.isci.2021.102703
The study was supported by the NIH Intramural Research Program at NINDS.
