Teav, T. | Search bioRxiv

bioRxiv2026

Distinct epigenetic and metabolic states reflect the regional identity of adult neural stem cells and prime their fate

Neural stem/progenitor cells (NSPCs) in the adult mouse brain reside in distinct niches, including the dentate gyrus (DG) and subventricular zone (SVZ). The contribution of cell intrinsic versus extrinsic factors to distinct fates of NSPCs and their neuronal progeny remains largely unknown. We here show that DG- and SVZ-derived NSPCs retain niche-specific chromatin accessibility states that predict neuronal subtype specification. Furthermore, metabolic profiling and gene expression analyses comparing DG- and SVZ-derived NSPCs revealed differences in carnitine synthesis pathways and lipid metabolism. Supplementation with carnitine or S-adenosylmethionine (SAM) induced chromatin remodeling via histone modifications, indicating that a metabolic-epigenetic cross-talk determines regional neuronal identity. Our findings show that NSPCs are intrinsically programmed by chromatin and metabolic states, and that metabolic interventions alter epigenetic landscapes and fate potential.

cell biology↗

bioRxiv2024

Eluding anemone nematocysts: are clownfish deprived of N-acetylated sugars in their skin mucus?

The clownfish - sea anemone system is a great example of symbiotic mutualism where host << toxicity >> does not impact its symbiont partner, although the underlying protection mechanism remains unclear. The regulation of nematocyst discharge in cnidarians involves N-acetylated sugars like sialic acid, that bind chemoreceptors on the tentacles of sea anemones, leading to the release of stings. It has been suggested that clownfish could be deprived of sialic acid on their skin surface, sparing them from being stung and facilitating mutualism with sea anemones. In this study, we sampled the skin mucus of two anemone symbionts, the clownfish Amphiprion akindynos and the juvenile damselfish Dascyllus trimaculatus, as well as two non-symbiotic adult damselfish Pomacentrus moluccensis and P. pavo. The free and total sialic acid content, including its conjugated form, and three other intermediates of this pathway were quantified using a stable isotope dilution mass spectrometry approach. We found significantly higher levels of sialic acid and its precursor in the non-symbiotic damselfishes. Concentrations of total sialic acid in anemone symbionts ranged between 13 {micro}M and 16 {micro}M, whereas the non-symbiotic damselfishes ranged between 21 {micro}M and 30 {micro}M. The presence of this metabolite and its precursors, as triggers of nematocyst discharge, in anemone symbionts, suggests that this is not the direct mechanism of protection or that the trigger is concentration dependent. This experiment demonstrates that anemone symbionts are not spared by nematocysts because of a lack of N-acetylated sugars, as previously thought.

molecular biology↗