Researchers create genetically engineered mice with ‘human-like’ telomeres, allowing effects of interventions to be observed in mammals.
Washington State University researchers have developed a genetically engineered mouse model that mirrors human telomere dynamics, with potentially significant implications for the study of aging and disease. The breakthrough, published today in Nature Communications, addresses a long-standing limitation in aging research, where conventional mouse models have failed to accurately represent human telomere biology.
Telomeres, the protective caps at the ends of chromosomes, play a crucial role in cellular aging. In humans, they gradually shorten with each cell division, ultimately leading to cellular senescence or death. However, traditional laboratory mice possess significantly longer telomeres and maintain high telomerase activity across most tissues, making them inadequate models for studying human aging and age-related diseases.
To overcome this challenge, the WSU research team engineered a novel strain of mice, known as HuT mice, which possess human-like short telomeres and a more restricted pattern of telomerase expression. The project, led by Professor Jiyue Zhu of WSU’s College of Pharmacy and Pharmaceutical Sciences, marks the first time a mouse model has been created with truly humanized telomeres. Unlike conventional mice, HuT mice exhibit telomerase repression in adult tissues, mirroring the regulation seen in human cells. This refinement allows researchers to observe the effects of telomere shortening within a living organism, rather than relying on isolated human cells in vitro.
“This is the first mouse model with truly humanized telomeres because telomerase isn’t expressed in adult tissues in this model,” said Zhu. “Our paper demonstrates that they exhibit human-like telomeres. Now, we aim to observe how these mice age.”
The potential implications of this work are far-reaching; it is hoped that HuT mice may allow scientists to explore potential interventions that protect or extend telomeres, offering insights into delaying age-related decline and extending healthy lifespan. The ability to study telomere dynamics in an intact organism also enables research into the influence of environmental and lifestyle factors on aging. One such project involves investigating how chronic stressors, such as sleep deprivation, affect telomere regulation. Collaborating with WSU’s Elson S Floyd College of Medicine, Zhu’s team will use HuT mice to examine how these stressors contribute to accelerated cellular aging, potentially uncovering new strategies for mitigating their effects.
Another potential application is in research into the connection between telomere length and cancer. While telomerase is essential for cell renewal, its overexpression enables cancer cells to maintain their telomeres indefinitely, allowing uncontrolled proliferation. By reducing telomerase expression selectively in cancer cells, researchers aim to develop novel therapeutic strategies to inhibit tumor growth.
The development of HuT mice was the culmination of a decade of work, beginning when researchers gained a deeper understanding of telomere regulation in humans and how it differed from other mammals. By replacing key non-coding sequences in the mouse TERT gene with human counterparts, the researchers successfully recalibrated telomere homeostasis in the new mouse model. Successive breeding generations stabilized telomere length to 10–12 kilobases – comparable to that seen in adult humans – while maintaining normal body weight and cellular function.
The work builds on decades of telomere research, dating back to pioneering work by Nobel laureates Elizabeth Blackburn and J Michael Bishop, with whom Zhu trained in the 1990s, and has secured $5 million in grants from agencies including the National Institute on Aging, the National Institute of General Medical Sciences and the US Department of Defense.
