Science may have uncovered a key reason why women tend to live longer and experience slower cognitive decline than men. A recent study suggests that a “silent” X chromosome in female brains may not be so silent after all. As women age, previously dormant genes from the inactivated X chromosome may reawaken, potentially offering cognitive protection.
Researchers from the University of California, San Francisco (UCSF), found evidence in both mice and humans that certain genes on the “inactive” X chromosome can escape suppression, particularly in brain cells crucial for learning and memory. This process appears to intensify with age, potentially slowing down cognitive aging in women.
The X chromosome carries about 5% of the human genome and has long been understudied in aging research. Since females have two X chromosomes (one from each parent), one is randomly silenced in each cell. However, the study found that in older mice, 3-7% of genes from the inactive X chromosome “escaped” inactivation, with significant expression in memory-related neurons.
To validate these findings in humans, researchers analyzed brain data and found that older women had increased expression of cognition-related genes, particularly PLP1, which is essential for neuron communication. Increasing PLP1 in aging mice improved learning and memory, highlighting its potential for future treatments.
This breakthrough underscores the importance of studying female-specific biology in aging. Understanding how the X chromosome influences brain health could lead to new therapies that benefit both men and women.