Biology subjects

Chen, C. T.

Publications and source records attributed to Chen, C. T..

3 recordsLinked to original sources

bioRxiv2026

Bright Days Buffer Nighttime Light: Daytime Illumination Shapes Sex Differences in Sleep and Circadian Regulation

Sex differences in sleep and wakefulness are well documented in humans but remain inconsistent in rodent studies, suggesting strong sensitivity to experimental context. In prior work, we observed no sex differences in sleep-wake architecture under relatively bright daytime light, raising the possibility that daytime illumination is a critical but underappreciated variable shaping sex-dependent sleep regulation. Here, we tested the hypothesis that daytime light intensity modulates sex differences in sleep-wake architecture and vulnerability to dim light at night (DLaN). Male and female C57BL/6J mice were exposed to acute (one night) or chronic (two weeks) DLaN (10 lux) under three daytime light intensities (50, 100, 300 lux). Sleep was assessed using electroencephalographic-based measures of vigilance states and slow wave activity (SWA). Dim daytime light (50 lux) unmasked robust sex differences in dark-phase sleep-wake architecture that were absent under brighter daytime light (300 lux). Acute DLaN reduced early-night wakefulness in both sexes under low daytime light but had minimal effect under bright daytime conditions. Following chronic DLaN, males exhibited reduced dim light-phase wakefulness and dampened rhythm amplitude, whereas females showed pronounced phase shifts, rhythm attenuation, and altered timing of SWA under 50 and 100 lux. These changes were largely prevented under bright daytime light. Together, these findings identify daytime light intensity as a critical contextual factor governing sex-specific regulation of sleep and vulnerability to nighttime light, providing a unifying framework to reconcile inconsistencies in the rodent sleep literature. HighlightsO_LIDaytime light intensity shapes sex differences in sleep-wake architecture C_LIO_LIAcute and chronic nighttime light elicit distinct sex-specific sleep responses C_LIO_LIFemales exhibit greater circadian and slow-wave vulnerability to nighttime light C_LIO_LIBrighter daytime light buffers sleep and circadian disruption C_LI

animal behavior and cognition↗

bioRxiv2026

Standardized brain and plasma EV enrichment pipeline validated for Single sample multi-Omic and fatty acids applications in Mouse and Human

Extracellular vesicles (EVs) are key mediators of intercellular communication, yet their molecular profiles across tissues and species remain poorly characterized, particularly due to currently available methods requiring a large amount of biological material (tissue or biofluids). Here, we established a workflow allowing the deep phenotyping of EV cargos starting from single samples of human and mouse origin. We took advantage of standardised EV isolation procedures and multi-omic techniques for the isolation and analysis of EVs from brain and plasma of human and mouse, integrating flow cytometric profiling, proteomics, miRNA sequencing, and fatty acid profiling. Here we report specific brain-derived EVs proteome, enriched in neuronal and glial proteins, polyunsaturated fatty acids profiles, and distinct miRNAs. At the periphery, we also report plasma-derived EVs signatures reflecting immune, metabolic, and systemic transport functions. Despite these expected material-specific differences, EVs from the same source displayed greater similarity across species than EVs from different material, supporting the translational relevance of mouse models. Importantly, using state-of-the-art miRNA profiling approach, we identified novel EV-specific miRNAs in human and mouse brain EVs, potentially allowing the exploration of new roles in neuronal signalling. Overall, we report here a method enabling deep multi-omic characterization from minimal starting material, offering a practical approach for studies with limited biological samples. These findings also demonstrate that the origin strongly shapes EV composition, highlighting conserved and species-specific molecular features, and provide a scalable framework for multi-omic investigations of EV biology. Summary StatementWe present a standardised workflow allowing multi-omic profiling of brain and plasma-derived EVs from minimal human and mouse material. Our findings reveal both tissue-specific and species specific EV molecular signatures.

neuroscience↗

bioRxiv2025

Dissociating the Effects of Light at Night from Circadian Misalignment in a Neurodevelopmental Disorder Mouse Model Using Ultradian Light-Dark Cycles.

Individuals with neurodevelopmental disorders (NDDs) often experience sleep disturbances and are frequently exposed to light during nighttime hours. Our previous studies using the Cntnap2 knockout (KO) mouse model of NDDs demonstrated that nighttime light exposure increases behaviors such as excessive grooming, reduces social interactions, and disrupts daily locomotor rhythms. To further evaluate the effects of nighttime light exposure, we exposed wild-type (WT) and Cntnap2 KO mice to an ultradian lighting cycle (T7), which alternates 3.5 hours of light and 3.5 hours of darkness. Circadian rhythms in activity, corticosterone levels, and clock gene expression are maintained under T7 lighting despite the presence of light during the usual night phase, whilst animals display increased depressive-like behaviors and reduce performance on the novel object recognition test. Based on these observations, we hypothesized that T7 lighting would mimic the impact of nighttime light exposure seen in standard light-dark cycles with dim light at night (DLaN). However, in this study, adult WT and Cntnap2 KO mice held under the T7 cycle did not show the increased grooming behavior or reduced social interaction observed in Cntnap2 KO mice exposed to DLaN. Regarding locomotor activity rhythms, the T7 cycle lengthened the circadian period and weakened the rhythm amplitude but did not abolish rhythmicity in either genotype. Finally, opposite to DLaN, neither the T7 cycle nor constant darkness (DD) elicited an increase in cFos expression in the basolateral amygdala in WT and KO mice. These results demonstrate that the adverse behavioral and neurobiological effects of nighttime light exposure in a model of a neurodevelopmental disorder depend on circadian disruption rather than light exposure alone, highlighting the importance of circadian stability as a protective factor in NDDS.

neuroscience↗