When cells experience sudden physical stress, like stretching or pressure, they can activate a fast, protective mechanism that shields their nuclei from destruction, according to a new study publishing June 3 in the Cell Press journal Biophysical Journal . This mechanism could help scientists develop therapies to prevent DNA damage, a major driver of aging and cell death.
“A lot of aging research has focused on the biological pathways activated after DNA damage occurs,” says author Hongyuan Jiang of the University of Science and Technology of China, Hefei. “Our study sheds light on a new mechanism of how cells physically protect themselves from the start.”
Epithelial cells make up the outer layer of the skin and the surfaces of many internal organs. They are constantly exposed to mechanical forces like stretching and osmotic stress, which happens when sodium or other ion concentrations suddenly change. For example, posture changes in humans can stretch the epithelial cells on skin by up to 25%, and the cells that line the intestines can experience a 20-fold increase in osmotic pressure after water intake. These external stresses can rupture the cell’s nucleus, snapping DNA strands.
Previous studies have found that actin, a type of protein in cells, can form a cap-like structure over the nucleus, acting like a safety helmet when cells experience stress. But the structure forms gradually over hours.
Jiang’s team wondered whether cells also have a defense mechanism against acute stress. To investigate, the researchers exposed epithelial cells to rapid hypotonic shock by suddenly exposing them to large amounts of water. The difference in ion concentrations inside and outside of the cells caused water to rush into the cells to restore balance.
Within minutes, the researchers saw a ring-like structure, composed mainly of actin, forming rapidly around the nuclei. The structure disappeared in about half an hour, once the cells adapted to the osmotic pressure.
The team also mechanically pushed on cells to mimic physical pressure. They saw the same structure form. But when the researchers applied the force slowly or gently, no ring appeared. The researchers also observed actin rings in mouse embryonic cells exposed to hypotonic shock, suggesting the mechanism exists in living organisms.
“The actin ring is like a seatbelt. It only kicks in when there is acute stress, similar to what happens in a car crash,” Jiang says.
Further experiments showed that the ring protects the nucleus by confining and stabilizing it. The assembly of the ring structure increased the expression of a structural protein called Lamin A/C around the nuclear membrane, making the membrane stiffer and less likely to rupture. When the team blocked the ring formation in some cells, the cells saw twice as many severely damaged DNA strands and deaths compared with cells that formed the ring normally after three rounds of hypotonic shocks.
“Aging cells tend to have lower levels of actin in them, which means they may not produce the ring structure as effectively as healthy cells,” Jiang says. “In the future, we want to explore if we can prevent DNA damage and slow cell aging by modulating actin dynamics in cells.”
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This work was supported by the National Natural Science Foundation of China, the Fundamental Research Funds for the Central Universities, and USTC Research Funds of the Double First-Class Initiative.
Biophysical Journal , Yang et al., “Transient perinuclear actin rings prevent cell aging and apoptosis via nuclear mechanical protection” https://www.cell.com/biophysj/fulltext/S0006-3495(26)00336-X
The Biophysical Journal ( @BiophysJ ), published by Cell Press for the Biophysical Society, is a bimonthly journal that publishes original research and reviews on the most important developments in modern biophysics—a broad and rapidly advancing field encompassing the study of biological structures and focusing on mechanisms at the molecular, cellular, and systems levels through the concepts and methods of physics, chemistry, mathematics, engineering, and computational science. Visit: http://www.cell.com/biophysj/home . To receive Cell Press media alerts, contact press@cell.com .
Biophysical Journal
Experimental study
Cells
Transient Perinuclear Actin Rings Prevent Cell Aging And Apoptosis Via Nuclear Mechanical Protection
3-Jun-2026