Neuronal Epigenetic Control of Metabolic Adaptation: A Conserved Role for JMJD-3.1 in Nutrient-Dependent Plasticity
The ability to adapt metabolic function to fluctuating environmental conditions is a hallmark of organismal fitness. The nervous system is a well-established regulator of organismal metabolism, integrating environmental cues to coordinate systemic physiological responses. Epigenetic mechanisms are increasingly recognized as mediators of neuronal plasticity, yet their specific roles in metabolic adaptation remain incompletely understood.
Using Caenorhabditis elegans as a model, we identify the conserved histone demethylase JMJD-3.1 as a critical neuronal regulator of metabolic adaptation to a high-fat diet (HFD). Surprisingly, loss of neuronal jmjd-3.1 is sufficient to rescue multiple HFD-induced phenotypes, including excessive fat accumulation, reduced exploration, and shortened lifespan. These findings suggest that JMJD-3.1 acts in neurons to modulate systemic metabolic responses, possibly by influencing neuroendocrine signaling pathways.
To uncover the underlying mechanisms, we are combining transcriptomic and epigenomic profiling of isolated neuronal nuclei to define JMJD-3.1–dependent gene regulatory programs in the context of dietary challenge. Our work supports a model in which conserved neuronal epigenetic pathways serve as hubs for metabolic adaptation, with implications for understanding brain-body communication in metabolic disease.
Neural representation of space: From compass coding to place coding in an insect brain
Each moving animal needs a sense of orientation. Whether it is a bat using a biosonar for mid-range orientation or migratory birds that keep their direction for thousands of kilometres, every individual must know its current location relative to the goal. Here, I summarize our recent findings on spatial processing in the insect brain. With brain recordings from tethered flying monarch butterflies that were free to steer with respect to a simulated sun, we showed that compass coding dramatically changed when the butterfly starts to fly. Through explicit perturbation of the compass or the butterflies’ goal direction, we characterized goal-direction neurons. While monarch butterflies are ideal organisms to study directional coding, they are less suited to study place coding. To this end, I recently shift my research focus on honeybees that daily forage in the same habitat. With neural recordings from freely walking honeybees, we started to study place coding.
