5mC and 5hmC Detection Highlights How Psychedelics Affect Brain Epigenetic Patterns

Psilocybin, a serotonergic psychedelic, produces long-lasting antidepressant effects, but the underlying mechanisms are not fully understood. This study examined epigenetic changes in the mouse brain after psilocybin treatment. Male C57BL/6 mice received either psilocybin or saline, and after 72 hours, DNA from the prefrontal cortex was analyzed using nanopore sequencing. The results showed 1,404 regions with altered 5-hydroxymethylcytosine (5hmC) levels, strongly enriched in the glutamatergic synapse pathway. In contrast, only 51 regions of altered 5-methylcytosine (5mC) were found, with no pathway enrichment. These findings suggest that psilocybin rapidly induces epigenetic modifications primarily through 5hmC, which may contribute to its sustained antidepressant effects and offer new targets for treating major depressive disorder.

Study at a glance

Abstract

Background: Psilocybin, a serotonergic psychedelic compound, has demonstrated long-term antidepressant effects, yet its underlying mechanisms remain unclear. Emerging evidence suggests that epigenetic modifications, particularly 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC), may play a role in its therapeutic action. Unlike passive demethylation, which requires cell division and occurs infrequently in neurons, active demethylation via TET enzymes rapidly converts 5mC to 5hmC, a process abundant in the brain. This study investigates changes in 5mC and 5hmC levels in key brain regions following psilocybin treatment. Material and Methods: Male C57BL/6 mice were divided into two groups: psilocybin-treated (n = 3) and saline-treated control (n = 3). After 72 hours post-treatment, prefrontal cortex (PFC) tissue was collected for DNA methylation analysis using nanopore sequencing, enabling genome-wide detection of 5mC and 5hmC at single-base resolution. Results: A total of 1,404 DhMRs were identified in psilocybin-treated mice, showing significant enrichment in the glutamatergic synapse pathway (q = 0.0009). In contrast, only 51 significant DMRs were found for 5mC, with no pathway enrichment detected. These findings suggest that 5hmC modifications, rather than 5mC, play a critical role in psilocybin's effects on synaptic plasticity and neuroplasticity. Conclusion: Preliminary findings suggest that psilocybin induces rapid epigenetic changes, primarily via 5hmC, in key brain regions involved in mood regulation. These changes may underlie the sustained antidepressant effects of psilocybin, potentially offering new therapeutic targets for Major Depressive Disorder (MDD). Future studies will focus on validating these results and exploring their long-term implications.