Human immune cells called macrophages can be warriors or healers, and what they become depends on magnesium, according to UT Health San Antonio School of Dentistry Professor Brij Singh, PhD.
"Macrophages can change from one phenotype to the other phenotype," said Singh, who is also associate dean for research and interim director of the Center for Regenerative Sciences. In macrophages, the warrior is the M1 phenotype, which creates inflammation to fight pathogens. The healer is the M2 phenotype, which eases inflammation and repairs damage.
What kind of cell a macrophage becomes is determined by a variety of signals from its environment, Singh explained, and a key signal is magnesium level. When a macrophage is full of magnesium, it becomes an M1 cell and goes into a warrior stance. When magnesium is low, the macrophage becomes an M2 cell and seeks to ease inflammation and repair damage. M2s are essential to healing, but in the presence of cancer cells, the tools they use to heal create a tumor-friendly environment.
What is magnesium's role in determining the kind of immune cell a macrophage becomes? Singh's lab has been studying this in relation to oral cancer, and his team has confirmed that low magnesium activates a protein on the cell membrane called TRPM7, which opens a doorway for the mineral to enter the cell. It’s called a magnesium channel, and when magnesium uses the TRPM7 channel to get into a macrophage, that cell becomes an M2...a healer.
If you need warriors, and healers are just going to foster tumor growth, you don’t want magnesium to use the TRMP7 channel.
"So if you can block these channels, then you can prevent the oral cancer or treat oral cancer as it progresses," Singh said.
This research is promising for other types of cancer, too.
"Other cancers will have the same mechanism, because those immune cells are throughout our body," Singh said. "So if somehow we can maintain higher magnesium levels in our cells, then we can maybe not have those cancer phenotypes growing."
Science & Medicine is a collaboration between TPR and The University of Texas Health Science Center at San Antonio, about how scientific discovery in San Antonio advances the way medicine is practiced everywhere.
