Newswise — A newly discovered regulatory mechanism helps the body control the rate of fat metabolism, according to a new study publishing on January 17 in the open-access journal PLOS Biology by Ligong Chen of Tsinghua University in Beijing and colleagues. The finding may lead to new drugs to help burn stored fat and reduce weight.
Fat tissue can be white, brown, or beige, differing not only in color but also in metabolism. White fat is principally a storage tissue, with a low rate of metabolism; brown fat tissue, on the other hand, is rich in mitochondria, and burns up stored fat, releasing heat to warm the body, a process called thermogenesis. After prolonged cold exposure, brown-like fat cells develop within white fat, making it beige, and beige fat cells also burn fat to keep the body warm.
A key stimulus for thermogenesis is the hormone norepinephrine, which exerts its effects at the cell surface, and is then taken up into the cell and degraded to prevent overstimulation. A mechanism for the uptake of norepinephrine from fat cells has previously been described, but its rate of uptake is relatively low, suggesting there may be another pathway.
In the new study, the authors found that beige fat cells in mice have high levels of a protein called organic cation transporter 3 (Oct3), which can import norepinephrine into the cells for degradation. The authors showed that reducing the level of Oct3, and thus slowing norepinephrine degradation, led to a higher rate of fat metabolism in beige fat and a higher body temperature. When exposed to prolonged cold, mice deficient in Oct3 increased beige fat content faster than their littermate controls, accompanied by increased activity of thermogenic and mitochondrial biogenic genes.
Gratifyingly, when they looked at human genetic association databases, the authors found that possessing versions of the OCT3 gene that make OCT3 protein with a reduced transport function was associated with a higher metabolic rate. Together, these results indicate that OCT3 plays an important role in regulating the rate of beige fat production and thermogenesis in both mice and humans.
“Our finding that a reduction in OCT3 activity can lead to more beige fat and increased thermogenesis indicating the importance of this transporter in catecholamine recycling in adipose tissues.,” Chen said. “Developing specific OCT3 inhibitors would open up new therapeutic possibilities for metabolic diseases.”
In your coverage please use this URL to provide access to the freely available article in PLOS Biology: http://journals.plos.org/
Press-only preview: https://plos.io/2SGVEOh
Citation: Song W, Luo Q, Zhang Y, Zhou L, Liu Y, Ma Z, et al. (2019) Organic cation transporter 3 (Oct3) is a distinct catecholamines clearance route in adipocytes mediating the beiging of white adipose tissue. PLoS Biol 17(1): e2006571.https://doi.org/10.1371/
Funding: National Key R&D Program of China (grant number No. 2018YFA0506903). received by L.C. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. National Science and Technology Major Projects for Major New Drugs Innovation and Development (grant number No. 2018ZX09711003-004-002). received by L.C. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Tsinghua University Initiative Scientific Research Program (grant number No. 20161080086). received by L.C. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. National Natural Science Foundation of China (grant number No. 81470839). received by L.C. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. National Institutes of Health (grant number GM117163). received by K.M.G. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
About PLOS Biology
PLOS Biology is an open-access, peer-reviewed journal published by PLOS, featuring research articles of exceptional significance, originality, and relevance in all areas of biology. For more information visit http://journals.plos.org/
Media and Copyright Information
For information about PLOS Biology relevant to journalists, bloggers and press officers, including details of our press release process and embargo policy, visit http://journals.plos.org/
PLOS Journals publish under a Creative Commons Attribution License, which permits free reuse of all materials published with the article, so long as the work is cited.
About the Public Library of Science
Public Library of Science (PLOS) is a nonprofit Open Access publisher, innovator and advocacy organization dedicated to accelerating progress in science and medicine by leading a transformation in research communication. The PLOS suite of journals contain rigorously peer-reviewed Open Access research articles from all areas of science and medicine, together with expert commentary and analysis. In addition to journals, the organization advances innovations in scientific publishing through Collections, Communities and The PLOS Blog Network. Founded to catalyze a revolution in scientific publishing by demonstrating the value and feasibility of Open Access publication, PLOS is committed to innovative and forward-looking solutions to scientific communication. For more information, visit http://www.plos.org.