From loops to labs, a bike group spurs scientific collaboration

Someone made an off-hand comment about pedaling to Costco for a hot dog, and suddenly Associate Professor of Immunobiology Michael D. L. Johnson was busting out mapping software to design a bike route taking riders on a 100-kilometer loop encompassing all three local warehouse stores. He named it the Costco 100 and invited his Saturday morning bike group to join him, treating themselves to a hot dog at each stop.

"It was a lot of fun," Johnson said of the October ride. "We weren't trying to burn rubber or anything – we were just hanging out, eating hot dogs."

Johnson's bike group includes several faculty members from the University of Arizona College of Medicine – Tucson Department of Immunobiology and the BIO5 Institute, as well as students, staff, spouses and others.

What began as a playful challenge created a space that extended well beyond the ride itself. Joining them for the inaugural Costco 100 was College of Medicine – Tucson doctoral student Ateh Zinkeng, who struck up a conversation with Johnson about his thesis research investigating the relationship between diet and liver cancer. He had encountered an obstacle.

"We're talking science, and he started talking about this protein he needs to purify," Johnson recalled. "In our laboratory, that's what we do – we purify proteins. We have the machinery and abilities to do those things. Now we're helping him."

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Liver mysteries

After completing the first two years of medical school, students throw themselves into scientific research to earn their doctorates. Zinkeng joined the lab helmed by Regents Professor of Medicine Dr. Juanita Merchant, division chief of gastroenterology and hepatology.

The Merchant Lab had just published a paper connecting colon polyps in mice fed a high-fat diet to a genetic mutation that produces a faulty HNF1-alpha protein. This misshapen protein leads to irregular cell growth and eventually the formation of polyps – but only in the context of a high-fat diet. After the study was completed, they noticed this mutation didn't just affect the colon, it also affected the liver.

"Because of that mutation, the liver is not able to function properly in clearing out excess fat," Zinkeng said. "If mice placed on this high-fat diet had this mutation, they tend to have a severe form of fatty liver disease – and eventually develop liver cancer."

Zinkeng hypothesized that fat molecules attach to and disable the faulty protein, causing the liver to be littered with clumps of fat that can't be cleared away. But he needed to design an experiment to test his idea.

"The first step is to purify this protein and design a small reaction where I can put the fat molecules and the HNF1-alpha protein together to see if they interact," he said. "I'm proposing that fat molecules bind to HNF1-alpha and impair its functions – in the absence of fat, the protein works just fine."

Protein problems

But to find out how this faulty protein interacts with fat, Zinkeng needs to pit them against each other in a test tube and see what happens. Getting his hands on fat molecules is easy, but securing a pure supply of the protein is not. The connections he had forged as a member of his bike group saved the day.

"Dr. Johnson's lab has a fancy automated system to isolate protein – in hours," Zinkeng said. Working alongside Johnson, Zinkeng is expanding his already formidable laboratory skills, and hopes that later this year he will uncover exactly how the faulty HNF1-alpha protein might increase disease risk in those eating fatty diets.

"I'm curious about understanding what happens when we eat high-fat food," he said. "We really don't know how ultra-processed and high-fat foods are impacting our physiology. To be in a lab studying that interaction, to come up with something novel, something new you're bringing to the field, was particularly enticing."

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Continuing the journey

Johnson hopes the Costco 100 will become an annual tradition, promoting both physical activity and a meeting of scientific minds.

"The Costco 100 was as pleasant as a 100-kilometer bike ride can be," Johnson said. "When you're having a conversation with somebody while riding, it blows by. You get the same amount of cardio, but it's more mentally stimulating."

"That was one fun ride," Zinkeng added. "I really enjoy the team and the people we get to bike with. Everyone is so passionate about what they do."

Zinkeng says his collaboration with the Johnson Lab is just one example of how the community he found around cycling has expanded his scientific horizons. He considers Johnson a mentor. This relationship, formed through shared miles and curiosity, has shaped both his training and his confidence as a scientist.

"This is somebody I'd really like to emulate, to have in my corner as I go through this training phase," he said.

Until the next ride, Zinkeng is keeping his sights set on his professional destination.

"In the future, I want to run a lab dedicated to combating cancer. Losing loved ones and having family members and friends pass away to cancer has motivated me to study the disease," he said. "There are days when the experiments don't work, and we have to troubleshoot and try again to answer questions that could potentially change how we look at gene-diet interactions. I think we'll add some great stuff to science – I can't wait."