C. elegans worms may hold key to new treatments for obesity in humans
Coincident with the widespread adoption of PSA screening, the proportion of American men diagnosed with organ-confined, low risk prostate cancer has increased significantly during the last two decades. In a study scheduled for publication in the February 2009 issue of The Journal of Urology, researchers report that for low-income men, the opposite is true, with
Full Post: Low income men diagnosed more often with advanced prostate cancer
A previously unknown mutation discovered in a common roundworm holds the promise of new treatments for obesity in humans, McGill University researchers say.
Their study was published Dec. 3 in the journal Nature , and was funded by the Canadian Cancer Society and the Canadian Institutes of Health Research.
In lean times, a normal Caenorhabditis elegans worm goes into a form of suspended animation called “dauer” that slows its metabolism and allows it to survive for extended periods without food.
“When they go into dauer, these worms radically alter their metabolism,” said Dr. Richard Roy, a cancer researcher at McGill’s Department of Biology specializing in the control of cell division. “They shut down everything energy-consuming, which includes foraging, cell division and reproduction.”
Unlike other “hibernating” organisms, C. elegans maintains a degree of mobility during dauer by stocking up on energy in the form of fats - or lipids - which they store in special cells or reserves.
“This allows them to live up to six months without eating, instead of the two weeks they would otherwise have,” Roy explained. A worm with the newly discovered mutation, however, will usually die within a week of going into dauer
“These mutants somehow cannot shut down the process of cell division, which is why we noticed them in the first place,” Roy said. “However, that’s not what kills them. They cannot adjust their metabolism correctly. They store up their six-month lipid reserves, but as soon as they shift into dauer they use them up within a few days. This is because they lack an enzyme that blocks the activity of a very important triglyceride lipase. Without this regulation the lipase burns up all the fat it encounters and destroys the worm’s energy reserves.”
This discovery was a near-accidental by-product of Roy’s regular line of research, searching for cells that abnormally disobey cellular signals in a cancer context, and he gives graduate student and study first author Patrick Narbonne much of the credit.
“Patrick was absolutely brilliant. He was so observant that he noticed these animals were dying way too early, and he also realized that they were not dying because of the cell-division issue.”
Roy and Narbonne believe this discovery, which will require considerable additional research, may have significant long-term implications for human health.
“I think we should start looking at the enzymes involved in this cascade, particularly in obese individuals. They are likewise accumulating lipids, but in a reverse situation to C. elegans, this enzyme isn’t recognizing it, or something is blocking its function. We’re making the case that we can uncouple this enzyme from its normal regulation. If we could develop drugs to do that selectively in fatty tissue, we’d be able to chew up all the fat.”
“This study fascinates me,” said Dr. Robert Sladek, one of Canada’s most prominent diabetes researchers, affiliated to the McGill Department of Human Genetics and the McGill and Genome Quebec Innovation Centre. “It will be exciting to see whether this pathway that controls energy storage and lifespan in worms plays a similar role in humans. The implications for patients with obesity and diabetes might be quite far-reaching.”
A Florida State University College of Medicine research team led by Yanchang Wang has discovered an important new layer of regulation in the cell division cycle, which could lead to a greater understanding of the way cancer begins. Wang, an assistant professor of biomedical sciences at the College of Medicine, said the findings will lead
Full Post: Scientists discover an important new layer of regulation in the cell division cycle
New research from University of California, Davis, shows why a species of tiny worm can learn to ignore an odor - information that could have implications for how human memories are formed. Scientists have known for decades that sensory neurons - nerves in places like our fingers, ears and eyes - begin the complex task of
Full Post: Odors can alter gene expression in an olfactory neuron
Biologists have discovered a mechanism that is critical to cytokinesis — nature’s completion of mitosis, where a cell divides into two identical daughter cells. The researchers have opened a new window on the assembly and activity of a ring of actin and myosin filaments that contract to pinch a cell at just the right time.
Full Post: New insights into cell division
Magazine articles describing ways to burn fat, lose weight, etc. are omnipresent in Western culture, but science’s understanding of the way fat is stored in the cells of the human body is rather slimmer. In this week’s issue of PLoS Biology, a new paper by Dr. Mathias Beller, Carole Sztalryd, and colleagues investigates some of
Full Post: Understanding lipid storage
After you eat a burger and fries or other fat-filled meal, a protein produced by the liver may send a signal that fat is on the way, suggests a report in the December issue of the journal Cell Metabolism, a Cell Press publication. Researchers have found in mice that the liver produces a protein called
Full Post: Adropin protein produced by the liver sends signal that fat is on the way in response to high-fat foods