Enhancing Thermogenesis in Beige Adipocytes.

The difference between brown and beige adipocytes is still unclear, in the first article it states that between brown and beige adipocytes they have comparable amounts of uncoupling protein 1, which suggests that they may have similar thermogenic capabilities. Beige adipocytes form in white adipose tissue in response to stimuli, they are formed as clusters of uncoupling protein 1.  In my last blog post, I wrote about a mechanism that brown adipocytes have that is able to convert chemical energy into heat by the usage of the uncoupling protein 1, through a process called thermogenesis. But there are other energy-expending mechanisms such as creatine and calcium cycling, these cycles can complement even substitute for uncoupling protein 1 thermogenesis. The researchers in the second article identified creatine metabolism as a signature of the mitochondria and due to its coupling of mitochondrial creatine kinase to oxidative phosphorylation through the carrier for ATP and ADP. They hypothesized that the creatine could deplete the ATP in the mitochondria to drive an ADP-dependent respiration in brown fat mitochondria, to do this the pathway would have to include creatine and creatine kinase mediated hydrolysis of ATP of drive a catalytic mechanism that would trigger the cycling of ATP production and consumption. So, the researchers tested whether or not creatine would be able to stimulate a substrate cycling and increase ADP dependent respiration in beige adipocyte mitochondria. In the end it was observed that creatine, ADP and oxygen consumption suggest a creatine driven substrate cycle, by detaching excess amounts of ADP the beige-fat mitochondria enhance respiration by maintaining a certain state of ATP synthesis. Their data suggested that creatine metabolism regulates the dissipation of energy in both brown and beige fat, it indicates that creatine metabolism has an important role in regulating adipose energy expenditure. With this data future studies can see how regulating the amount of brown and beige adipose within our bodies will allow us to maintain a constant body weight with correct nutritional intake and adequate exercising regimes. Creatine metabolism can work hand in hand with brown and beige adipose thermogenesis to open up possibilities of manipulating the thermogenesis in people with metabolic diseases.  

Article sources:

Harms, M., & Seale, P. (2013). Brown and beige fat: development, function and therapeutic         potential. Nature Medicine, 19(10), 1252-1263. doi:10.1038/nm.3361

Kazak, L., Chouchani, E. T., Jedrychowski, M. P., Erickson, B. K., Shinoda, K., Cohen, P., & ...  Spiegelman, B. M. (2015). A creatine-driven substrate cycle enhances energy expenditure and thermogenesis in beige fat. Cell, 163(3), 643-655. doi:10.1016/j.cell.2015.09.035