Posted on Dec 16, 2016, 6 a.m.
Researchers believe that they have found the secret for turning "bad" white fat into "good" brown fat
Scientists from the University of Pennsylvania believe that they have found the secret for turning "bad" white fat into "good" brown fat.
Senior author of the study, Dr. Zoltan P. Arany, related that he and his colleagues’ experiment resulted in deleting a gene in the white fat cells of mice. The gene, or protein, foliculin (FLCN) is a tumor suppressor. Once the gene was deleted, the protein TFE3 was able to enter the cells' nucleus. TFE3 would then bind to DNA. That activated a protein known as PGC-1ß which plays a major role in regulating cell metabolism.
Usually, that process does not occur, because TFE3 cannot enter the cell nucleus because two other genes, FCLN and mTOR, work to keep it out and keep the browning process switched off. When the FLCN was deleted in the mice, the white cells became browner. Those cells began producing more mitochondria, the oxygen reactors providing chemical energy inside the cells. In the brown fat cells, mitochondria convert energy into heat.
When deleting the gene, the white cells came to resemble the preferred brown cells. That process switched on a set of genes that changed the cells’ structures and boosted the ability of the mitochondria to consume oxygen and changed the patterns of gene expression.
The human body has different types of fat that fulfill different purposes. If white fat cells, known as white adiposities, are filled with fat molecules, obesity can likely result. Brown fat cells, known as brown adipocytes, are what forms the "baby fat" in infants, who have much more brown fat than adults. Brown fat transfers the energy from food into heat, a process known as thermogenesis. The heat protects the body from cold, and the process of fat burning prevents obesity and related disorders such as diabetes, heart disease, and cancer.
Dr. Arany states that there is still a long way to go and more research is needed, but the scientists are hopeful that this discovery will eventually lead the way to a new drug treatment that will prevent diabetes and reduce obesity by to pushing white fat to become brown fat.
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The tumor suppressor FLCN mediates an alternate mTOR pathway to regulate browning of adipose tissue, Shogo Wada et al., Genes Development, doi: http://www.genesdev.org/cgi/doi/10.1101/gad.287953.116, published 2 December 2016, abstract.