What Can Sea Urchins Tell Us About Aging?

Andrea Bodnar

When you consider ways to study the process of aging in humans, you might not consider looking to one of the ocean’s most widely-studied invertebrates—the sea urchin—but that’s exactly what BIOS researchers Dr. Jeannette Loram and Dr. Andrea Bodnar did in a recent study published in the journal Mechanisms of Ageing and Development.

As humans age they exhibit characteristic declines in cellular processes, such as a loss of reproductive capacity and a cessation of growth. At the genetic level these are manifested as changes in the expression of the genes that regulate these functions; for example, a decline in the expression of mitochondrial genes involved in energy production.

Sea urchins, on the other hand, can grow indeterminately and retain the ability to reproduce throughout their lifespan. Some species live more than 100 years and exhibit what researchers term “negligible senescence,” meaning they show no conspicuous signs of aging, such as an increase in mortality or declines in cellular processes, over their lengthy lifespan. This “alternative life history,” combined with their close genetic relationship to humans (compared with other invertebrates), makes sea urchins a model organism for many types of research.

In the first study of its kind to look at age-related changes in gene expression in an organism with an alternative life history, Loram and Bodnar looked at gene expression profiles in three tissues (muscle, nerve, and esophagus) of the purple sea urchin Strongylocentrotus purpuratus. They observed age-related changes in all three tissues involving a variety of cellular functions, including DNA metabolism, signaling pathways involved in development and tissue regeneration, and apoptosis—or programmed cell death.

The article, “Age-related changes in gene expression in tissues of the sea urchin Strongylocentrotus purpuratus,” details the changes observed in each tissue type and provides comparisons to other species, providing a unique opportunity for insight into the complex process of aging.