George Washington University scientists from St. Louis, Missouri have found that the stomach naturally produces more stem cells than previously realized. These stem cells probably repair stomach damage from infections, the foods we eat, and the constant tissue insults from stomach acid.
The reversion of adult cells to a stem cell fate is one of the goals of stem cell research. Shinya Yamanaka’s research group at the Center for iPS Cell Research and Application and the Institute for Frontier Medical Sciences at Kyoto University won the Nobel Prize in 2012 for his work on reprogramming adult cells into embryonic-like stem cells, otherwise known as induced pluripotent stem cells (iPSCs) that was initially published in 2006.
A collaborative research effort between scientists from Washington University School of Medicine in St. Louis and Utrecht Medical Center in the Netherlands have shown that this reversion from adult cells to stem cells occurs naturally in the stomach on a regular basis.
Jason Mills, associate professor of medicine at Washington University, said, “We already knew that these cells, which are called chief cells, can change back into stem cells to make temporary repairs in significant stomach injuries in significant stomach injuries, such as a cut to damage from infection. The fact that they’re making this transition more often, even in the absence of noticeable injuries, suggests that it may be easier than we realized to make some types of mature, specialized adult cells revert to stem cells.”
Chief cells normally produce a protein called pepsinogen. In the presence of stomach acid, pepsinogen activates itself and once active, the new protein product, pepsin, degrades proteins. Pepsin in an enzyme that is most active in the acidic environment of the stomach. Another enzyme released by chief cells is chymosin, which is also known as rennet. Chymosin curdles the proteins in milk and makes them easier to degrade.
Mills and his groups are in the process of studying the transformation of chief cells into stem cells, for injury repair. Mills would also like to investigate the possibility that the potential for growth unleashed by this change may contribute to stomach cancers.
Mills and his collaborator Hans Clevers from the Netherlands have identified stomach stem cell marker proteins that show that chief cells become stem cells even in the absence of serious injury. In the case of serious injury, either in cell culture of in animal models, more chief cells become stem cells, making it possible to repair the damage in the stomach.