A UT Southwestern Medical Center biochemist was recently named the winner of the 2019 Breakthrough Prize in Life Sciences for his discovery of an enzyme that helps defend against infections and cancers.
James Chen is the second UT Southwestern faculty member to win the $3 million prize. He sat down with host Justin Martin to discuss his research for KERA News' segment thet focuses on the latest health-related technologies developed in North Texas — incidentally, also called Breakthroughs.
On the enzyme discovery:
This enzyme is called cGAS. What is does is, it will recognize DNA from microbial pathogens and then, when it binds to the DNA, it becomes activated. Then it will trigger an immune response against the microbial pathogens.
The one thing that this enzyme does is that it will synthesize a small molecule called cyclic GMP-AMP. We call it cGAMP for short, and this molecule is very potent in activating the immune system.
On the two immune systems:
The innate immune system actually our first line of defense. It's faster, so as soon we get infected by a virus or bacteria, the innate immune system is the first system to activate. Once the system is activated then it will provide this sort of immediate control of an infection.
It will fight off infections, but at the same time, it will also activate the so-called adaptive immune system.
The adaptive immune system is the one that I think most people know about: it's T-cells and B-cells. It's ort of the antibody response.
If we get an infection — by a flu virus, for example — in the first few days, its the innate immune system that is working. Then a few days later, our T-cells and B-cells get called in, and then they come and eradicate infections.
On how his discovery expanded our understanding of the immune systems:
So for the immune system to work, first we need to know that we've been infected by a virus or bacterium. How do we know? One way that our immune system recognizes these infections is to detect DNA from microbial pathogens.
People have known for a long time that DNA can stimulate our immune system, but exactly how that works was not clear.
So, our work solved a major problem in our understanding of this immune sensing of microbial pathogens. That is how our immune system detects microbial DNA. Then, we discovered the DNA sensor, which we called cGAS.
James Chen is a professor of molecular biology and director of the Center for Inflammation Research at UT Southwestern Medical Center.