"Zombie cells," also known as senescent cells, are associated with age-related diseases and can trigger inflammation.
A new study has started to unravel the mystery behind a process known as "cryptic transcription," which occurs in senescent cells.
Understanding why cryptic transcription occurs in zombie cells and its effects on aging could have significant implications for aging and longevity research.
The researchers aim to determine if cryptic transcription occurs at specific genes in a regulated fashion or primarily at long genes due to dysregulation, and whether different groups of cryptic sites are transcribed in separate cell types.
The researchers aim to determine if cryptic transcription occurs at specific genes in a regulated fashion or primarily at long genes due to dysregulation, and whether different groups of cryptic sites are transcribed in separate cell types.
“Zombie cells,” also known as senescent cells, have long been associated with age-related diseases such as cancer, Alzheimer’s, and osteoarthritis.
These cells stop dividing due to damage or stress, but they don’t die. Instead, they secrete molecules that trigger inflammation, which can be harmful as the body ages.
A new study published in Nature Aging has started to unravel the mystery behind a process known as “cryptic transcription,” which occurs in senescent cells.
Cryptic transcription describes the production of short RNA molecules from small sections of DNA. In normal cells, RNA serves as a blueprint for building proteins.
However, the function of these cryptic RNAs remains unknown. Payel Sen, a molecular biologist at the National Institute on Aging, believes that these small molecules might deplete the cell’s resources, making it less efficient over time.
Alternatively, these RNA instructions could generate tiny proteins that interfere with the cell’s normal functions.
Epigenetic Changes and Their Role in Cryptic Transcription
Sen and her team have discovered more than 350 “cryptic sites” in human senescent cells, which represent gene fragments used to make unusual RNAs.
They found that epigenetic changes at these sites are not present in young, healthy cells, and this may explain why cryptic transcription occurs.
Epigenetics refers to molecules that attach to DNA and influence gene expression.
In zombie cells, the researchers observed changes in histones, which are proteins that DNA wraps around.
These changes seem to be connected to the cells’ ages. In senescent cells, these epigenetic modifications expose parts of the genome to the cell’s RNA-making machinery.
In contrast, these gene fragments remain hidden and unexpressed in young cells.
“Zombie cells,” also known as senescent cells, have long been associated with age-related diseases such as cancer, Alzheimer’s, and osteoarthritis.
The Impact on Aging and Longevity Research
Understanding why cryptic transcription occurs in zombie cells and its effects on aging could have significant implications for aging and longevity research.
Identifying whether these senescent cells become less efficient or produce harmful small proteins might lead to new methods for prolonging youthfulness.
To further investigate the role of cryptic transcription, Sen and her team used a technique called PRO-cap to study the start site of transcription in DNA.
They found that cryptic transcription occurs throughout a cell’s life, but they identified numerous cryptic sites unique to senescent cells that could have age-related functions.
In a related study with liver cells from mice, the researchers observed higher levels of cryptic transcription in older mice.
They also noticed that cryptic sites were almost exclusively found in cells from female mice, suggesting that sex differences might play a role in cryptic transcription.
Future Research Directions
As the researchers continue to study cryptic transcription, they aim to determine if it occurs at specific genes in a regulated fashion or primarily at long genes due to dysregulation.Â
Additionally, they plan to investigate whether different groups of cryptic sites are transcribed in separate cell types. This would support the hypothesis that cryptic sites are regulated.
By identifying over 350 cryptic sites in human senescent cells and exploring the mechanisms driving the process, Sen and her colleagues have taken significant steps toward understanding the role of cryptic transcription in aging.
The insights gained from this research could potentially pave the way for new interventions to prolong life and prevent age-related diseases.
