Scientists have discovered a genetic mechanism that allows neurons to change their identity and function in response to environmental conditions, according to a fresh study from the Institute of Biomedicine of Valencia (IBV-CSIC). The research, published in Proceedings of the National Academy of Sciences (PNAS), used the nematode Caenorhabditis elegans as a model to show how a specific epigenetic process acts like a “lock” that suppresses the neurons’ ability to absorb serotonin — a neurotransmitter linked to mood regulation in humans.
The study found that this lock, involving the methylation of histone H3 at lysine 9 (H3K9me), prevents certain genes from being read, effectively silencing the neuron’s potential to take on a serotonin-related role. But, when environmental demands shift, this lock can be opened, allowing the neuron to adopt new functions and altering the animal’s behavior. This mechanism reveals how nervous systems adapt to surroundings through reversible changes in gene expression without altering the underlying DNA sequence.
Researchers noted that all cells in an organism share the same genetic information, but different cell types — such as skin, liver, or neurons — emerge based on how genes are interpreted. Epigenetic changes, like the one identified in this study, determine how DNA is read to produce specific cellular functions. By demonstrating that neuronal identity can be dynamically regulated in response to external cues, the findings offer insight into the molecular basis of behavioral flexibility, and adaptation.
The discovery may have implications for understanding human neuropsychiatric conditions. Since serotonin transport is implicated in disorders such as depression, anxiety, and autism, uncovering how its regulation can be epigenetically controlled opens new avenues for investigating the origins of these conditions. The researchers emphasized that while the study was conducted in a simple worm model, the core mechanisms involved are evolutionarily conserved and may operate similarly in more complex brains.
The work was led by researcher Nuria Flames and her team at IBV-CSIC, who sought to explain how neurons can acquire new functions without losing their original identity, and how such changes can become permanently encoded in a species’ evolutionary history. Their findings show that what appears to be a fixed cellular role can, in fact, be modulated by environmental triggers acting through well-known epigenetic pathways.
