When activated, the molecule slows the movement of food through the intestine, allowing the animal to absorb more nutrients and thus gain weight. Without this signal, the animals weigh less.
The study shows that the host can use bacterial byproducts not only as a source of nutrients, but also as chemical signals to regulate body functions. It also points the way to a potential method of controlling weight, the researchers said.
“It’s quite possible that blocking this receptor molecule in the intestine might fight a certain kind of obesity by blocking absorption of energy from the gut,” said Dr. Masashi Yanagisawa, professor of molecular genetics at UT Southwestern and a senior co-author of the study, which appears online in Proceedings of the National Academy of Sciences.
Humans, like other animals, have a large and varied population of beneficial bacteria that live in the intestines. The bacteria break up large molecules that the host cannot digest. The host in turn absorbs many of the resulting small molecules for energy and nutrients.
“The number of bacteria in our gut far exceeds the total number of cells in our bodies,” said Dr. Yanagisawa.
“It’s truly a mutually beneficial relationship. We provide the bacteria with food, and in return they supply energy and nutrients,” he explained.
Using mice, the researchers focused on two species of bacteria that break up dietary fibers from food into small molecules called short-chain fatty acids. Dr. Yanagisawa’s team previously had found that short-chain fatty acids bind to and activate a receptor molecule in the gut wall called Gpr41, although little was known about the physiological outcome of Gpr41 activation.
The researchers disrupted communication between the bacteria and the hosts in two ways: raising normal mice under germ-free conditions so they lacked the bacteria, and genetically engineering other mice to lack Gpr41 so they were unable to respond to the bacteria.
In both cases, the mice weighed less and had a leaner build than their normal counterparts even though they all ate the same amount.
The researchers also found that in mice without Gpr41, the intestines passed food more quickly. They hypothesized that one action of Gpr41 is to slow down the motion that propels food forward, so that more nutrients can be absorbed. Thus, if the receptor cannot be activated, food is expelled more quickly, and the animal gets less energy from it.
Because mice totally lacking Gpr41 were still healthy and had intestinal function, the receptor may be a likely target for drugs that can slow, but not stop, energy intake, Dr. Yanagisawa said.
Other UT Southwestern researchers involved in the study were co-lead author and graduate student Abdullah Shaito; Dr. Toshiyuki Motoike, assistant professor of molecular genetics; research specialist Clay Willams; and Dr. Robert Hammer, professor of biochemistry. Researchers from Washington University School of Medicine, the Japan Science and Technology Agency and Howard Hughes Medical Institute in Chevy Chase, Md., also participated.
The study was funded by the National Science Foundation, the National Institutes of Health, the W.M. Keck Foundation, the Japan Science and Technology Agency and HHMI.
Dr. Masashi Yanagisawa -- http://www.utsouthwestern.edu/findfac/professional/0,2356,18207,00.html
Aline McKenzie | Newswise Science News
Not of Divided Mind
19.01.2017 | Hertie-Institut für klinische Hirnforschung (HIH)
CRISPR meets single-cell sequencing in new screening method
19.01.2017 | CeMM Forschungszentrum für Molekulare Medizin der Österreichischen Akademie der Wissenschaften
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
19.01.2017 | Earth Sciences
19.01.2017 | Life Sciences
19.01.2017 | Physics and Astronomy