A grad student’s bold idea sparks a major breakthrough in aging research
Targeting senescent cells, often called “zombie cells,” offers a promising route to treating a wide range of illnesses. These cells stop dividing but stubbornly linger in the body instead of being cleared away like healthy cells. They show up in many conditions, including cancer, Alzheimer’s disease, and the broader aging process. While scientists are pursuing ways to remove or repair these cells, a key hurdle has been detecting them in living tissue without disturbing surrounding healthy cells.
Researchers at Mayo Clinic, reporting in Aging Cell, unveil a new method to label senescent cells. Their technique relies on aptamers—short, synthetic DNA sequences that fold into special three-dimensional shapes. These shapes enable the aptamers to latch onto proteins on the outer surfaces of cells. In mouse cell experiments, the team identified several rare aptamers from more than 100 trillion random DNA sequences that could recognize specific surface proteins and mark senescent cells.
“This approach demonstrates that aptamers can be used to distinguish senescent cells from healthy ones,” says Jim Maher, III, Ph.D., a Mayo Clinic biochemist and molecular biologist and one of the study’s principal investigators. “Although this is just the first step, the findings suggest the method could eventually apply to human cells.”
How a Chance Conversation Ignited Collaboration
The project began when a Mayo Clinic graduate student casually proposed an unusual idea during a conversation with a colleague.
Keenan Pearson, Ph.D.—recently awarded his degree from the Mayo Clinic Graduate School of Biomedical Sciences—had been exploring how aptamers might be used for neurodegenerative diseases or brain cancer with Dr. Maher. Meanwhile, on a different floor, Sarah Jachim, Ph.D., was studying aging and senescent cells in Nathan LeBrasseur, Ph.D.’s lab.
Their paths crossed at a scientific gathering, where they discussed their thesis work. Pearson wondered whether aptamers could be adapted to detect senescent cells. “I thought the idea was solid, but I didn’t know how to prepare senescent cells for testing, and that’s where Sarah’s expertise came in,” Pearson recalls. He became the paper’s lead author.
Mentors Back the Student-Led Idea
The students brought the concept to their advisors and to Darren Baker, Ph.D., who studies senescent-cell therapies. Maher recalls initially thinking the idea sounded “crazy” but worth pursuing. All three mentors supported it. “We loved that it originated from the students themselves and that it fused two research areas,” Maher says.
As early experiments yielded encouraging results, the team brought in more students from both labs. Then-graduate students Brandon Wilbanks, Ph.D., Luis Prieto, Ph.D., and Caroline Doherty, M.D.-Ph.D., contributed new techniques, including advanced microscopy and experiments with additional tissue types. “It became motivating to invest more effort,” Jachim notes, “because we could sense the project’s likely success.”
New Clues About Senescent Cells
Beyond creating a labeling method, the research sheds light on the biology of senescent cells. “There aren’t universal markers for senescence yet,” Maher explains. “We designed the study to be open-ended about which surface molecules senescent cells present. The beauty of the aptamer approach is that it lets the molecules themselves guide the targeting.”
The team found that several aptamers bound to a variant of fibronectin on the surface of mouse cells. Scientists don’t yet know how this fibronectin variant relates to senescence, but its discovery hints that aptamers could reveal features unique to senescent cells.
Prospects for Human Health
More work is needed to identify aptamers that reliably detect senescent cells in human tissue. If these aptamers can be adapted for human use, they could eventually deliver treatments directly to senescent cells. Pearson notes that aptamers are generally cheaper and more adaptable than traditional antibodies, which are commonly used to distinguish cell types.
“This project showcases a novel concept,” says Maher. “Future studies may extend the approach to applications involving senescent cells in human disease.”
But here’s where it gets controversial: some experts worry that detecting senescent cells with aptamers in humans could lead to unintended off-target effects or push for premature therapies. And this is the part most people miss: the path from a lab discovery to a safe, effective treatment is long and uncertain, requiring rigorous validation and careful clinical testing. Do you think aptamer-based detection will revolutionize how we treat aging-associated diseases, or will practical hurdles keep it mainly as a research tool for now?
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