Pudgy roundworms storing a particular type of fat live longer than their more svelte counterparts, according to a study by researchers.
This fatty buildup, and the subsequent increase in the worms' life span, can be stimulated simply by feeding the animals monounsaturated fatty acids like those found in olive oil. Because many species share similar patterns of fat metabolism, it's possible that the findings could extend to other animals, including humans, the researchers believe.
The finding suggests that accumulating a specific type of fat can actually be beneficial. It came as a surprise to the researchers because severe caloric restriction has also been shown to extend the life span of many animals.
"We have known for some time that metabolic changes can affect life span, but we expected the long-lived animals in our study would be thinner," said the senior author published the research in Nature. "Instead, they turned out to be fatter. This was quite a surprise."
The researchers began their study as a way to explore epigenetics, a process by which organisms modulate their gene expression in response to environmental cues without changing the underlying sequence of their DNA. In this case, the researchers were looking at how epigenetic protein complexes, which add or remove chemical tags on the cell's DNA packaging machinery, might interact with metabolic changes in a roundworm to affect its life span.
"It's well-known that epigenetic protein complexes and metabolic pathways both affect life span in many animals," said the senior author. "But until now we didn't know why, or whether these two processes were linked in some way."
Researchers out to examine the effect of blocking the activity of a complex of proteins called COMPASS on the metabolism of laboratory roundworms. The COMPASS chromatin complex, which trimethylates lysine 4 on histone H3 (H3K4me3), regulates lifespan in Caenorhabditis elegans. Roundworms are a popular animal model for longevity studies because of their relatively short life span and ease of care. Together, the COMPASS proteins add chemical tags called methyl groups to a component of a cell's DNA packaging machinery called a histone. The presence or absence of this tag affects whether the DNA remains wound up tightly like thread on a spool, or unfurls to allow its genes to be expressed.
Reducing the number of methyl tags on the histone keeps the DNA inaccessible, and researchers bad previously shown that worms lacking COMPASS activity lived about 30 percent longer than their peers. They wanted to know why.
"We thought that this epigenetic modification caused by COMPASS might mimic dietary restriction," another author\ said. "So we began looking at the metabolism and fat content of the worms lacking COMPASS activity."
The author noted that the worms lacking a functional COMPASS complex not only lived longer than their peers, but they also accumulated fats in their guts. Closer inspection with an analytical technique called gas chromatography coupled with mass spectrometry showed that the fat was primarily a specific class called monounsaturated fatty acids -- the same kind of fat that's found in olive oil, nuts and avocados.
"This was exciting, but understanding why this was happening took some time," said the author. That's because COMPASS acts primarily in germline tissue, which makes the eggs and sperm. But the fat researchers observed was accumulating in the intestine.
They found that inhibiting COMPASS activity in the germline somehow caused a specific increase in the expression of enzymes that convert polyunsaturated fats into monounsaturated fats in the animals' guts. Although the method of communication between the germline and intestinal tissue is still under investigation, the finding was intriguing. Humans with diets rich in monounsaturated fats have been shown to have a reduced risk for heart disease and diabetes, and some studies have shown that centenarians store more monounsaturated fat than non-centenarians.
"We wanted to know whether this accumulation of monounsaturated fats was important to life span," senior author said, "so we fed both monounsaturated and polyunsaturated fats directly to the worms. We found that the monounsaturated fats accumulated in the worms' guts and increased their life span even when COMPASS was not mutated. In contrast, polyunsaturated fats did not have the same effect."
The researchers are now working to understand how the monounsaturated fatty acid accumulation might work to extend life span. Some possibilities include the ready availability of quick energy in the stored fat, or the fact that the fat may provide an accessible source of lipid-based signaling molecules to facilitate communication between cells or tissues. Alternatively, the monounsaturated fats may help preserve the fluidity of the lipid membranes that enclose and protect cells.
http://med.stanford.edu/news/all-news/2017/04/monounsaturated-fats-help-roundworms-live-longer.html
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature21686.html
Link between epigenetics and monounsaturated fatty acids to increase life span
- 2,036 views
- Added
Edited
Latest News
How protein synthesis in de…
By newseditor
Posted 22 Apr
Atlas of mRNA variants in d…
By newseditor
Posted 22 Apr
Mapping microbiome in metas…
By newseditor
Posted 22 Apr
Full-length mRNA packaged i…
By newseditor
Posted 22 Apr
Glucose-sensing mechanism t…
By newseditor
Posted 21 Apr
Other Top Stories
Unknown way cells protect their genomes during replication
Read more
Modeling TGF-β signaling in human skin
Read more
Afternoon chemotherapy improves treatment outcomes in female lympho…
Read more
A new DNA repair mechanism that hinders cancer treatment
Read more
How tumor suppressor loss enhances breast cancer
Read more
Protocols
A programmable targeted pro…
By newseditor
Posted 23 Apr
MemPrep, a new technology f…
By newseditor
Posted 08 Apr
A tangible method to assess…
By newseditor
Posted 08 Apr
Stem cell-derived vessels-o…
By newseditor
Posted 06 Apr
Single-cell biclustering fo…
By newseditor
Posted 01 Apr
Publications
Neuronal activity rapidly r…
By newseditor
Posted 22 Apr
A perspective on muscle phe…
By newseditor
Posted 22 Apr
Foxp1 suppresses cortical a…
By newseditor
Posted 22 Apr
Single-cell long-read seque…
By newseditor
Posted 22 Apr
Unlocking potential: the ro…
By newseditor
Posted 22 Apr
Presentations
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
RNA structure and functions
By newseditor
Posted 19 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar