|Hibernating bears rely on UCP1 to stay warm. Other UCPs play roles in stem and cancer cells. (source: U.S. Fish and Wildlife Service)|
For those of you who drive a stick shift, imagine stepping on the clutch and the gas pedal of your car at the same time. What happens? The engine revs and generates heat while the car goes nowhere. In the brown fat cells of the body, a protein called Uncoupling Protein 1 (UCP1) essentially functions in the same way to help generate heat in the absence of adequate physical activity such as in babies and hibernating mammals.
It turns out that a family of UCP proteins exists that also regulates the body’s energy production, or metabolism, but the other UCPs have been less understood. Now, in a study published in PLOS, researchers report a connection between UCPs, stem cells, and cancer.
The research team from the University of Veterinary Medicine in Vienna showed that only UCP2 is present in embryonic stem cells where metabolic rates are generally high due to the energy demands of the continual cell division of these unspecialized cells.
UCP4, on the other hand, was only seen in nerve cells, which divide much less frequently than stem cells. Based on those results the team looked at UCP levels while stimulating stem cells to become nerve cells. The team observed that UCP2 fades away and UCP4 ramps up as the stem cells transform into nerve cells.
What’s fascinating is that unlike normal nerve cells, neuroblastoma cells, which are cancerous, have no UCP4 protein and instead only UCP2 is detectable as is seen in stem cells. In fact, previous studies had shown that UCP2 is present in cancer cells, which divide frequently and have high energy needs, similar to stem cells.
So these studies give a new glimpse of UCP2 and 4 functions and also provide an indicator of a stem cell’s transition into a specialized cell. The results also point to a potential signal to detect when a specialized nerve cell is heading down a cancerous path. Lead author Anne Rupprecht, in press release picked up by Science Daily, pitches the importance of the work this way:
The composition of UCPs in the cells discloses information about their current condition. UCP2 could therefore give an indication at an early stage, if a cell is on the way to becoming a cancer cell. Even a classification of the tumor’s malignancy would eventually be possible. A faulty mechanism in the nerve cells could lead to a functional disorder and, for instance, to a neurodegenerative illness like Parkinson’s disease.