(Press-News.org) Immune cells perform a previously unsuspected role in the brain that may contribute to obesity, according to a new study by UC San Francisco researchers.
When the researchers fed mice a diet high in saturated milk fats, microglia, a type of immune cell, underwent a population explosion in the brain region called the hypothalamus, which is responsible for feeding behavior.
The researchers used an experimental drug and, alternatively, a genetic approach to knock out these microglia, and both strategies resulted in a complete loss of microglia-driven inflammation in the hypothalamus. Remarkably, doing so also resulted in the mice eating less food each day than did their untreated counterparts, without any apparent ill effects.
Furthermore, removing microglia from mice only reduced food intake when the content of saturated fat from milk in their diets was high. It had no effect on mice fed a low-fat diet, or a diet high in other types of fat, including olive oil or coconut oil.
UCSF postdoctoral fellow Martin Valdearcos Contreras, PhD, first author on the paper, published in the December 11, 2014 issue of Cell Reports, discovered that when mice consumed large amounts of saturated fats, the fat entered their brains and accumulated in the hypothalamus.
According to the senior scientist for the study, Suneil Koliwad, MD, PhD, an assistant professor of medicine at the UCSF Diabetes Center, the microglia senses the saturated fat and sends instructions to brain circuits in the hypothalamus. These instructions are important drivers of food intake, he said.
Microglia are primarily known for causing inflammation in the brain in response to infection or injury, but the new study indicates that they also play a key role in shaping the brain's response to diet, according to Koliwad.
Outside the brain -- in fat tissue, the liver, and muscles -- other immune cells, called macrophages, trigger inflammation in response to "diet-induced obesity," Koliwad said. This inflammation is implicated in triggering insulin resistance, a late stage event on the road to type 2 diabetes.
However, overeating causes microglia to accumulate much more quickly in the hypothalamus than macrophages accumulate in peripheral tissues, Koliwad said. But until now, the effects of this microglial build-up were unknown.
"As opposed to classically defined inflammation, in which immune cells build up in tissues where environmental insults have created disarray, microglial activation in the brain may be a part of a normal physiological process to remodel brain function in response to changes in the composition of food intake," Koliwad said.
"When the intake of saturated fats is chronically high, this microglial sensory network may be hijacked, and this has the potential to mediate increased food consumption and promote more rapid weight gain.
"Targeting microglia may therefore be a novel way to control food intake in the face of consumption of a fat-rich diet, something that is quite common in today's world," he said.
INFORMATION:
The research was funded by the National Institutes of Health and by the UCSF Diabetes Family Fund.
UCSF is the nation's leading university exclusively focused on health. Now celebrating the 150th anniversary of its founding as a medical college, UCSF is dedicated to transforming health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes top-ranked graduate schools of dentistry, medicine, nursing and pharmacy; a graduate division with world-renowned programs in the biological sciences, a preeminent biomedical research enterprise and top-tier hospitals, UCSF Medical Center and UCSF Benioff Children's Hospitals. Please visit http://www.ucsf.edu.
PHOENIX, Ariz. -- Dec. 12, 2014 -- Using a basic genetic difference between men and women, the Translational Genomics Research Institute (TGen) has uncovered a way to track down the source of a neurological disorder in a young girl.
TGen's discovery relies on a simple genetic fact: Men have one X and one Y chromosome, while women have two X chromosomes. This women-only factor was leveraged by TGen investigators to develop a highly accurate method of tracking down a previously unrecognized disorder of the X-chromosome.
The study of a pre-teen girl, who went years ...
With the ball at the three-point line near the top of the key, what will Tim Duncan of the NBA's San Antonio Spurs do? Pass to a player posting up? Or does he take a shot? An analysis by Disney Research of player tracking data, however, suggests the highest probability is a pass to guard Tony Parker on his left.
It's just one play, by one player, in one sport - and perhaps not that hard for the average courtside observer to anticipate - but with the field of sports becoming more driven by sports analytics, predicting the next thing that a player will do has become a major ...
A new National Science Foundation (NSF) report reveals the number of U.S. citizen doctoral graduates in science, engineering and health fields, who remain in the United States, tracks closely with their intent to stay in the United States at the time of graduation. However, there are noticeable differences for doctoral graduates who were temporary visa holders at the time of graduation.
According to the report, 96.4 percent of U.S. citizen doctoral graduates from academic years 2001-09 reported their intent to live in the United States, a measure referred to as the expected ...
December 12, 2014 - All children should undergo vision health screening between age 36 and 72 months--preferably every year--using evidence-based test methods and with effective referral and follow-up, according to recommendations published in the January issue of Optometry and Vision Science, official journal of the American Academy of Optometry. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.
The National Expert Panel to The National Center for Children's Vision Health makes recommendations for vision health screening in ...
MADISON, Wis. - As a fundamental unit of life, the cell is central to all of biology. Better understanding how complex cells evolved and work promises new revelations in areas as diverse as cancer research and developing new crop plants.
But deep thinking on how the eukaryotic cell came to be is astonishingly scant. Now, however, a bold new idea of how the eukaryotic cell and, by extension, all complex life came to be is giving scientists an opportunity to re-examine some of biology's key dogma.
All complex life -- including plants, animals and fungi -- is made up of ...
The genomes of modern birds tell a story: Today's winged rulers of the skies emerged and evolved after the mass extinction that wiped out dinosaurs and almost everything else 66 million years ago.
That story is now coming to light, thanks to an international collaboration that has been underway for four years.
The first findings of the Avian Phylogenomics Consortium are being reported nearly simultaneously in 23 papers--eight papers in a special issue this week of Science, and 15 more in Genome Biology, GigaScience and other journals.
The results are funded in part ...
An ancient meteorite and high-energy X-rays have helped scientists conclude a half century of effort to find, identify and characterize a mineral that makes up 38 percent of the Earth.
And in doing so, a team of scientists led by Oliver Tschauner, a mineralogist at the University of Las Vegas, clarified the definition of the Earth's most abundant mineral - a high-density form of magnesium iron silicate, now called Bridgmanite - and defined estimated constraint ranges for its formation. Their research was performed at the Advanced Photon Source, a U.S. Department of Energy ...
Chicago, IL, and New Haven, CT, December 12, 2014 - The Yale School of Forestry & Environmental Studies and The Associated Press-NORC Center for Public Affairs Research today released the first set of findings from its inaugural environment poll. The poll surveys a nationally representative sample of American adults and provides a portrait of what the public thinks and feels about environmental issues, and what actions they are taking as consumers.
Findings from the first report indicate that most Americans say the United States ought to take a leadership role in combating ...
VIDEO:
A wide-field movie by GOES-WEST of the North Pacific from Dec. 9-12, 2014 reveals the violent rain storms pouring moisture on the "Pineapple Express " jet stream into California in mid-December....
Click here for more information.
The ''Pineapple Express'' happens when warm air and lots of moisture are transported from the Central Pacific, near Hawaii, to the Eastern Pacific Ocean. An animation of satellite imagery from NOAA's GOES-West satellite showed the stream of ...
Tropical Cyclone Bakung is moving in a westerly direction over the open waters of the Southern Indian Ocean and NASA's Aqua satellite captured an image of the sea storm.
Aqua passed over Bakung on Dec. 12 at 07:35 UTC (2:35 a.m. EST) and the MODIS instrument aboard took a visible image of the storm. The image showed that deeper convection (stronger currents of rising air that form the thunderstorms that make up the tropical cyclone) was occurring around the low-level center of circulation, so the center was not apparent in the MODIS imagery. The bulk of the clouds associated ...
