With the Researcher Spotlight, the Microbial Systems Initiative aims to introduce you to the breadth and diversity of research interests and potential growth opportunities on the University of Illinois at Urbana-Champaign campus. We hope that by highlighting both the researchers and their research, we can help you to learn more about and connect with your colleagues to enhance multidisciplinary research and education in microbial sciences here at Illinois.
Jason Ridlon, Ph.D. is an assistant professor of gut microbiology with appointments in the Department of Animal Sciences, the Division of Nutritional Sciences and the Carl R. Woese Institute for Genomic Biology. Prof. Ridlon is helping to find treatment strategies to improve human health and animal well-being. He studies gut microbiology, specifically the biochemistry and molecular biology of steroid and bile acid biotransformations by the gut microbiota. He is trying to understand how microbial metabolites promote gastrointestinal tract diseases such as liver and colorectal cancers, as well as essential hypertension. Prof. Ridlon obtained his Ph.D. in anaerobic bacteriology from Virginia Commonwealth University School of Medicine in 2008 and remained as a postdoctoral fellow in the Departments of Microbiology & Immunology and Internal Medicine, Division of Gastroenterology and Hepatology until 2012.
What is your research in microbial systems about?
The major contribution of my laboratory is identifying genes involved in steroid and bile acid metabolism by gut bacteria. I have named these collective genes the “sterolbiome”. Host derived steroids affect bacterial growth and thus microbiome structure and function. Microbes also modify host steroids generating unique signaling molecules that affect host physiology in profound ways. Thus, for the past several years we have been discovering and characterizing sterolbiome enzymes. This is necessary groundwork for the next step in our lab, which is to determine the role of the enzymes in altering the host metabolic profile and effects on physiology, including disease.
How are you conducting your research?
Research in my lab seeks to understand steroid metabolism from the structure of bacterial enzymes up to bacterial communities in gnotobiotic animals, and clinical samples. Our research starts by identifying a bacterial strain that we can demonstrate metabolizes steroids. Next, we either sequence the genome, or consult a genome for the bacterial strain if it is available. From there, candidate genes are identified and their biochemical function screened. Then in parallel, we work to understand the structure and mechanism of the reaction catalyzed by the sterolbiome enzyme, and the function of the gene in the gut ecosystem (microbe-microbe interactions) and on host physiology and disease (host-microbe interactions). The questions that we wish to address in the latter experiments are bringing us into the territory of bacterial genetics and/or synthetic biology. The germ-free model organisms that we are currently focusing on include the mouse, piglet, and chicken.
How does being a part of the Illinois community support and enhance your research?
One of the advantages of being a part of the University of Illinois is the spirit of interdisciplinary collaboration. Whenever you can work with and learn from faculty expertise and perspective that is distinct from your own, new questions emerge along with the excitement that comes from new terrain being explored. This is particularly true in my home department of Animal Sciences with diverse expertise from gut microbiology to immunology, bioinformatics, human disease, nutrition, and the biology of production animals. As an affiliate of the Microbiome Metabolic Engineering Theme at the Carl R. Woese Institute for Genomic Biology, I have access to expertise, facilities, and equipment that complements and extends what I can do in my home department. I also have several collaborations with faculty in the Division of Nutritional Sciences and the ability to recruit top graduate candidates. Most importantly is the spirit of collegiality and collaboration that I have found at Illinois. It is a joy to work with wonderful colleagues, including Rex Gaskins, Isaac Cann, Sharon Donovan, John Erdman, Andrew Steelman, Rod Mackie, Hannah Holscher, Kelly Swanson, Yong-Su Jin, and many more.
How will your research or work improve society or reach people?
My research is focused on working out how bacteria alter host steroids, and identifying strategies to shift this metabolism towards the formation of steroids that will impact health in a positive way. It is my hope that intervention strategies developed in my lab will one day find their way to the clinic. I am also interested in further exploring the role of steroid metabolism in the growth, well-being, and reproduction of production animals. Society advances with the accumulation of knowledge. If I can add to the body of knowledge in my field, I believe this will improve society.
Do you have a personal story to share or path that led to your interest in this area of study?
My path to the study of the gut microbiota was a matter of chance. As Louis Pasteur said, "chance favors the prepared mind". When I was an undergraduate at Bridgewater College, I was doing field and lab research with a microbiologist, Dr. Stephen F. Baron. My interest at the time was fisheries ecology and my work was in crayfish pigmentation. Dr. Baron saw that I was capable and wanted a career in science, so he contacted his former postdoctoral advisor, Phillip B. Hylemon, and asked if I could spend a summer doing research. I was somewhat hesitant since the research was in fecal bacteria, a far cry from my passion of studying the largemouth bass. Not having any clear path to fisheries ecology, I decided to see what anaerobic microbiology was like. I worked very hard, and after the summer I was given a position as a research technician. I found the work fascinating. It was during this time that the field transitioned from largely culture-based and defining the stool microbiota based on “fingerprints” using a PCR technique called DGGE to next-generation sequence-based. The term “microbiome” was on everyone’s tongue. Phil Hylemon’s lab split between working out bile acid cell signaling in the liver and bile acid metabolism by the gut microbiota. I read the steroid microbiology literature starting from the 1950s through the early 1980s and much of it gave vital clues to finding the genes encoding sterolbiome enzymes. However, the technology was just not available at the time and interest waned. Luck or not, I was in the right field at the right time and now had a research path that I could build a career on. It was another bit of good fortune that brought me to Illinois. I had met and talked with Professors Bryan White and Rod Mackie at a gut microbiology meeting in Scotland while I was a postdoc. Prof. White was a former Ph.D. student in Phil Hylemon’s lab. When the position I currently hold opened up, Prof. White contacted me about applying to the position. I was already well aware of the stellar history and reputation that Illinois has for microbiology. As a graduate student, I read manuscripts from Marvin Bryant, Carl Woese, Abigail Salyers, and Meyer Wolin. I wrote several reviews on bile acid and sulfur metabolism, and had cited many of H. Rex Gaskins’ important works on sulfur as a genotoxin. It was an easy decision to come here. The rest of the story is now unfolding, and while I have some view of how my research will progress in the next few years, part of the fun of research is the unexpected. It's about recognizing opportunities and making the best decisions you can each day.
