Aging is linked to changes in how DNA is folded in many brain cells
The folding changes tracked closely with shifts in gene activity and cell identity.
Science Daily · Scientists discover a hidden brain shift that begins around age 50Aging is linked to changes in how DNA is folded inside a wide range of brain cell types.
The researchers saw widespread and coordinated shifts in the organization of the genome. DNA is folded in three dimensions inside the cell, and that folding helps decide which genes are active.
Those structural disruptions were the folding shifts described above. "The progressive structural disruptions were closely linked to shifts in gene regulation and cell identity, potentially revealing a fundamental feature of aging in the human brain," said Bing Ren, scientific director and chief executive of the New York Genome Center and a professor of genetics and development at Columbia University.
The researchers also found signs that cells maintaining the blood-brain barrier decline with age. That barrier is a layer of cells lining brain blood vessels that controls what passes from blood into brain.
Questions people ask
What exactly does the blood-brain barrier do?
It is a tightly sealed layer of cells lining blood vessels in the brain. It lets in nutrients and oxygen while keeping out germs, toxins, and many drugs, and when it weakens, unwanted molecules and inflammatory signals can leak in more easily.
What does it mean for DNA to be physically folded or organized?
The DNA in each cell is about six feet long if stretched out, so it must be folded carefully to fit inside the nucleus. The pattern of folds brings some genes into open, active areas and tucks others away, which helps control what each cell does.
Do these changes cause dementia?
The study only shows that these changes happen alongside aging in healthy brains. Researchers have not yet shown whether the DNA refolding or barrier-cell decline directly causes Alzheimer's or other dementias, though both could make the brain more vulnerable.