Kaplan, K. | bioRxiv Science

bioRxiv2026

Metabolostasis failure thresholds are linked with network topology, metabolite solubility, and translational control

Cells maintain metabolite homeostasis (metabolostasis) by buffering fluctuations in metabolite levels, yet the limits of this buffering and the mechanisms underlying metabolic toxicity remain poorly understood. To study this, we systematically overfed metabolites in Saccharomyces cerevisiae and quantified associations with growth inhibition, intracellular aggregation, and multiomic perturbations. We identify metabolite-specific failure thresholds at which amyloid-like aggregates are observed, with graded growth inhibition detectable at sub-threshold concentrations, suggesting toxicity mechanisms beyond transporter saturation. Metabolites with higher network influence and broader pathway participation are associated with higher failure thresholds and smaller pathway disturbances. These patterns are associated with chemical properties and solubility: more soluble metabolites, while broadly tolerated, are associated with localised aggregates at their failure thresholds, whereas less soluble metabolites are associated with larger systemic pathway disruptions. Multiomic integration identifies a two-tiered translational regulatory architecture characterising cellular resilience to metabolic overfeeding. General resilience is associated with transcriptional commitment to resource conservation via attenuation of anabolic pathways. Metabolite-specific defense is characterised by high-magnitude translational regulatory events; for example, engagement of aromatic catabolism under phenylalanine overfeeding and energetic control pathways under glycine overfeeding. Together, our results operationally define metabolostasis as a cellular system associated with constraint of metabolite concentrations, coordination of network and pathway-level regulation, and buffering against amyloid-like aggregation, highlighting how network topology, pathway architecture, and chemical properties are associated with metabolic resilience and toxicity thresholds.

cell biology↗

bioRxiv2025

Alprazolam induces anterograde amnesia for contextual fear memory and alters dorsoventral hippocampal neuronal ensembles in female mice

Benzodiazepines (BZDs) are commonly prescribed anxiolytic drugs that act on GABAa receptors, and can result in anterograde amnesia, or the inability to form new memories. While BZDs have been used for decades, the brain regions and neuronal mechanisms responsible for this detrimental side effect are largely unknown at the systems neuroscience level. To analyze the effects of BZDs on long-term memory, activity-dependent ArcCreERT2 x eYFP mice were injected with Alprazolam 30 minutes prior to a 3-shock contextual fear conditioning (CFC) procedure and encoding ensembles were tagged with eYFP. Mice were re-exposed to the same context 5 days later, and retrieval cell activation was analyzed using the immediate early gene (IEG), c-Fos, allowing us to determine which brain regions undergo changes after alprazolam injection. Additionally, we address the question of whether alprazolam induces state-dependent memory by altering the timelines of injection. We found that 1) alprazolam treated male and female mice exhibit a decrease in memory retention and, 2) alprazolam treated female and male mice show a decrease in memory retention with saline injection prior to re-exposure, 3) alprazolam treated female mice exhibit increased EYFP+ (encoding) activation in the dCA1 and enhanced engram activation in the dCA3, and 4) alprazolam treated females showed less c-Fos+ activation in the vCA1. These results suggest that alprazolam induces sex-specific ensemble activation throughout the hippocampus and will help us understand the long-term memory deficits associated with BZD use.

neuroscience↗