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A research team at Harvard Medical School, led by is studying how they can treat obesity. Recently they determined that by changing bad white fat into good brown-like fat using CRISPR/Cas9, mice subjects were healthier than their obese counterparts.

Brown fat is the good kind of fat. We often call it baby fat, because babies and hibernating animals have a lot of it, and it can disappear quickly. In brown fat there is a lot of mitochondria, which are power factories in the cell which use glucose to produce energy. White fat is the bad kind of fat. It mainly functions as a storage for glucose and has very little mitochondria.

At low temperatures the mitochondrion in brown fat turns on, producing energy and heat as a by-product. The glucose needed to power the mitochondria in brown fat comes from the foods we eat and the glucose storage in white fat.

Depending on what our body needs, we also have beige fat. These can function as white fat and store glucose, but when needed turn brown-like to use glucose to provide energy and heat.

Tseng and her team found that they could make white fat behave like brown fat (they aptly named it human brown-like cells, or HUMBLE cells) by turning on the UCP1 gene. This gene codes for UCP1 protein, which is vital for mitochondria to turn on and produce heat, literally burning glucose.

CRISPR/Cas9 was used to edit the UCP1 gene. This method introduces or removes parts of the cell's DNA, turning on or off genes depending on the need. Mice were used to see how this could make a difference. HUMBLE cells were injected into one group of obese mice. A second group was injected with white fat cells and a final group with brown fat cells.

Tseng found that the mice injected with HUMBLE or brown fat cells weighed less than the mice with white fat cells. They also saw that there was an interaction between the injected HUMBLE cells and native brown fat cells.  Those brown fat cells used up the most blood glucose, rather than the HUMBLE cells.

is so important because obesity is a common risk factor for heart disease, strokes, diabetes, degenerative disease of the joints and most cancers.

By using similar methods to control fat in people, doctors may be able to prevent obesity, making them healthier. This will also decrease the prevalence of obesity-linked diseases.

Monkey experiments are now being performed at the ľ¹Ï¸£ÀûÓ°ÊÓ of Massachusetts Medical School with chemical ways of producing brown-like cells. If these are promising, we may see something in clinical trials one day.