Rejuvenation
Researchers at Whitehead Institute are breathing new life into the study of rejuvenation, the ability of cells to repair and replenish tissues — and potentially learning how to slow or reverse the changes our cells experience over time.
The root words of rejuvenation mean “young again.” While we still can’t turn back the hands of time, Whitehead Institute researchers are studying the biological markers of aging in order to better understand what cellular processes underlie the changes our bodies undergo over the years. Their work helps us understand what it means to “age” as a person, and may someday lead to therapies that can mitigate some of the effects of the aging process.
“Our bodies change dramatically in a lot of ways as we age,” says Whitehead Institute Member Iain Cheeseman. “The connection between the ability of cells to divide and proliferate to repair and replenish tissues and what changes in our bodies as we age is something we're really curious to investigate. And I think we have some molecular hooks that we can explore now that we didn't even just a couple years ago.”
Cheeseman’s work on cell division investigates not only how cells divide, but what’s going on when cells are not dividing. Cells face an onslaught of challenges over time. “One of the biggest challenges that aging cells and their proteins face is oxidative damage,” Cheeseman said. When a cell undergoes too much damage, he went on, it can lose its ability to divide. “It basically is entering this irreversible pause state, where it's going to start sending a bunch of signals that are sometimes problematic for tissue inflammation, or are interrelated to other kinds of diseases and cancer, and that can be a problem." Cheeseman’s work could eventually inform therapies for rejuvenating aging cells, prolonging life or extending the fertility window for women.
Whitehead Institute Member Peter Reddien is also studying a form of rejuvenation — or rather, regeneration. His work on regenerative worms called planarians is revealing basic principles of how animals can rebuild their tissues when they are damaged. Planarians have never been documented to die of old age — in fact, they can reproduce by tearing themselves in half, meaning that every planarian at Whitehead Institute has the identical genetic makeup of one original animal. Reddien’s work illuminates the cell types and genetic programs that confer this form of extreme longevity to the worms.
Some cellular markers of aging are programmed into the cells themselves; the calls are coming from inside the house, so to speak. Researchers in the lab of Whitehead Institute Member Siniša Hrvatin study the effect of reduced metabolism on the body’s epigenetic clocks — a series of changes over time to the structureal organization of DNA that affects which genes are expressed. These epigenetic markers are often used to measure one’s “biological age” — the progression of which, unlike chronological age, differs slightly from person to person. Hrvatin is using these markers to determine how different states — specifically torpor, a state kind toof “suspended animation” used by many animals to survive extreme conditions — could affect the process of biological aging.
Whitehead Institute Member Yukiko Yamashita addresses another pre-programmed hallmark of aging: the loss of ribosomal DNA. The product of that DNA, ribosomal RNA, together with proteins, forms cells’ protein-making factories. As time progresses, most cells in the human body lose some of their ribosomal DNA — but one cell type is able to retain the correct amount, and even make more. Yamashita’s recent work explores how germ cells — sometimes called “immortal” cells due to their ability to escape the fate of somatic cells, which die with each organism and are mare completely anew in the next generation — are able to bypass the gradual loss of ribosomal DNA over the years. Whitehead Institute Director Ruth Lehmann also studies these “immortal” cells, focusing on their life cycle and how they are able to persist throughout generations without aging to transmit the information needed to create an entirely new organism.
In this multimedia collection, we dive deeper into each of these researchers’ projects — and more. Explore the links below to learn how researchers at Whitehead Institute are breathing new life into the study of rejuvenation.
