"The gut microbiome is a very important mediator of the environment we live in"

“In 2017, I got my PhD at the China Pharmaceutical University [in Nanjing] and was seeking a postdoc position. I sent my CV to Professor Oluf Pedersen, who was very interested in my work and invited me to apply for a Marie Skłodowska-Curie Actions Postdoctoral Fellowship. He said: ‘If you’re interested, just come [to Copenhagen]. We have a grant proposal workshop and you can have a meeting with me.' We submitted my proposal in September 2017, and it was approved in January 2018. I contacted Oluf again and he just said: 'Welcome.' I had already started a postdoc at Columbia University in New York, so Oluf gave me half a year to switch. I left Columbia in August and joined CBMR in November.”

What did Columbia say?

"Because the Novo Nordisk Foundation Center for Basic Metabolic Research is very famous, the people at Columbia know Oluf well and just said: 'He's an exceptional research pioneer and excellent supervisor and it’s a great opportunity for you to work with him. But it will be a totally new area from what you are doing at Columbia. If your heart is really at the microbiome field, then please follow your heart and working together with Oluf will be fantastic'."

You’re interested in microbiota [the trillions of microbes in the body] and their connection to metabolic disease. What came first — your interest in metabolic disease or in microbiota?

"My interest in metabolic disease began during my PhD. I have a background in metabolomics [the study of chemical processes involving metabolites, the intermediate or end products of metabolism] and my focus was on establishing a methodology to profile metabolites in different biological compartments. We did a lot of work exploring the imbalanced metabolite profiles of different metabolic diseases, but we didn’t know how to study the mechanisms of these changes. Then I read a paper of Oluf’s in Nature about the impact on human gut microbiota and alterations in host serum metabolites. It was fantastic work and I decided that this was what I wanted to do. I contacted Oluf and switched from metabolomics to gut microbiota."

Why is the topic so interesting?

"We know that metabolite changes are the difference between the disease and the control, but we don't know what’s driving them. I’m trying to explain the mechanisms underlying this association by studying the gut microbiome. Many others are too, so it’s a hot topic. Oluf has also inspired me to find the genes in the gut microbiome that regulate the production of metabolites. That’s a way for me to understand the changes of metabolites in different metabolic diseases. At Columbia I learnt how to study the function of these different metabolites, so there are always two questions on my mind. Why do these metabolites change? And what is their function?"

What could the connection be between the behaviour of our gut microbiome and our metabolism?

"For each bacterium, there are genes, and those genes have functions. They synthesise many different enzymes that regulate the production of metabolites in our circulation, in our tissue, in different organs. These metabolites have functions, too, and regulate their host. For example, if we treat our adipose tissue [body fat] with specific metabolites, they will turn this tissue brown and ultimately help us lose weight. I think this is a complete chain."

To what extent do you think the microbiome is the primary driver of obesity and diabetes?

"It's difficult to put a number on it because our environment is very complicated. Factors like diet, drug use, lifestyle and geography may all impact the gut microbiome and host metabolism. But I can say that the gut microbiome is a very important mediator of the environment we live in, and our bodily reactions."

Has your research affected your own diet?

"Yes, the traditional food in China is always thought to be tasty, however, can be relatively ‘unhealthy’. We eat a lot of fried food, a lot of very oily, heavily processed food. I think people in Copenhagen have a healthy dietary type. Oluf even gave me a list of the vegetables to eat in my everyday life, which was very helpful. I’ve now switched to a healthy diet. I eat less fat and less meat, drink low-fat milk, and eat more fruit and vegetables. I think it helps a lot because I’ve felt more energetic and active since coming to Copenhagen. Also, I would like to add, the people here really like doing exercise, whenever I was out, I could always see people running by me. This is very impressive."

Where did you live in Copenhagen?

"In Østerbro, close to Maersk Tower."

What does your partner do?

"She's a Research Assistant in Oluf's group [Liwei Lyu], though we work on different projects."

Are you enjoying life in Copenhagen?

"Yes, we like the work-life balance in Copenhagen. My son was born at Rigshospitalet and he is now a two-year senior baby in his daycare. My wife and I are satisfied with the harmony between working at CBMR and family life with our son. We enjoy managing our jobs and maintaining our home. Unfortunately, we lack social activities due to the pandemic, but I believe everything will be back in the very near future."

What would you miss most about Copenhagen if you were to leave it?

"The people and their healthy lifestyle. People cycle and eat healthy food. I have to be honest, I don't like the winters here, but the summer in Copenhagen is fantastic."

Interview by James Clasper. Edited for clarity and concision.