Biology subjects

Sloan, A. R.

Publications and source records attributed to Sloan, A. R..

4 recordsLinked to original sources

bioRxiv2026

Hemodynamic Signals Reshape Biological Inference in Widefield Calcium Imaging

Widefield calcium imaging is widely used to study cortex-wide neural dynamics, yet fluorescence signals are strongly influenced by hemodynamic fluctuations arising from blood volume and oxygenation changes. Although hemodynamic correction is frequently applied, it remains unclear whether vascular contributions represent a modest preprocessing concern or systematically bias biological interpretations of cortical activity. Here, we used dual-wavelength imaging to determine how hemodynamic correction reshapes inference of cortical dynamics across mouse lines expressing GCaMP6s, GCaMP6f, and jGCaMP8m, across multiple analytical domains, and under healthy and glioblastoma conditions. We systematically compared uncorrected and corrected signals using analyses spanning functional parcellation, connectivity, spectral structure, brain-behavior coupling, and low-dimensional network-state dynamics. Hemodynamic correction consistently reduced global functional connectivity, increased network modularity, redistributed spectral power away from slow-frequency dominance, and reorganized multivariate representations of cortical state space. These findings demonstrate that vascular signals do not behave as unstructured measurement noise but instead introduce organized variance that propagates across analytical pipelines and influences inference of cortical dynamics. The consequences of this bias were particularly relevant in glioblastoma, where tumor-associated vascular remodeling amplifies the mismatch between fluorescence signals and underlying neuronal activity. In this disease setting, correction revealed hemispheric asymmetries, reduced network-state entropy, and constrained trajectories within cortical state space that were obscured in uncorrected recordings, demonstrating that vascular remodeling can fundamentally alter interpretation of tumor-associated brain dynamics. More broadly, vascular signals systematically biased estimates of functional organization, network architecture, brain-behavior relationships, and disease-associated phenotypes. Together, these findings establish hemodynamic correction as a critical determinant of biological interpretation in mesoscale calcium imaging rather than a simple preprocessing refinement.

neuroscience↗

bioRxiv2026

NeuroPupil: A generalization-first framework for scalable and biologically informative cross-species pupillometry

Quantitative pupillometry provides a noninvasive window into brain state and neurological function, but its broader use across experimental and clinical settings is limited by challenges in achieving accurate, scalable, and generalizable measurements. Here, we present NeuroPupil, a deep learning framework for high-throughput, cross-species pupillometry that emphasizes robust generalization across subjects, behavioral contexts, and imaging conditions. Through systematic benchmarking of training strategies and network architectures, we identify pooled multi-subject training combined with an optimized U-Net architecture as a key determinant of reliable and transferable pupil tracking performance. Across diverse mouse and human datasets, NeuroPupil achieves improved accuracy and substantial gains in computational efficiency compared to existing approaches, enabling practical analysis of large-scale datasets. We further demonstrate that improved pupil tracking fidelity enhances downstream biological inference: NeuroPupil-derived pupil features significantly improve prediction of distributed cortical activity in behaving mice and preserve diagnostically relevant temporal structure in human clinical recordings. These findings highlight the importance of precise and scalable measurement for linking pupil dynamics to brain activity and clinical phenotypes. By integrating benchmarking, scalability, and accessible software tools, NeuroPupil provides a reproducible framework for large-scale pupillometry and facilitates its application in systems and translational neuroscience.

neuroscience↗

bioRxiv2025

Platelets drive immune suppression and glioblastoma growth in a sex-dependent manner via PAR4 signaling

Sex differences in cancer outcome, including that of glioblastoma (GBM), are shaped by biological, hormonal, and immunological factors and impact disease progression, treatment responses, survival, and tumor microenvironment (TME) interactions. Platelets regulate the immune responses and tumor progression in many cancers, but it is not clear how they contribute to these sex-based differences by affecting the dynamics of the TME. Here, we show that GBM patients exhibit heightened platelet reactivity driven by PAR4 signaling. In murine GBM models, both pharmacological inhibition of PAR4 using BMS986120 and genetic deletion of PAR4 significantly prolong survival in females but not males. This survival advantage is estrogen dependent: it is preserved in chromosomal male-hormonal female mice within the four-core genotype model and is rescued in ovariectomized mice treated with estrogen. The survival benefit is TME specific and is mediated by platelet-driven enhancement of CD8 T cell infiltration into the tumor. Inhibition of platelet PAR4 signaling increases calcium signaling through an estrogen-dependent interaction between PAR4 and estrogen receptor {beta} (ER{beta})--a receptor interaction not previously described. PAR4-activated platelets within the TME suppress CD8 T cell function, and depletion of CD8 T cells abolishes both the tumor-induced platelet reactivity and the survival benefit conferred by PAR4 inhibition. These findings establish platelet-mediated PAR4 signaling as a critical driver of tumor progression and identify sex-specific immune responses as key to therapeutic efficacy.

cancer biology↗

bioRxiv2025

Development and Characterization of Triazole-Based WDR5 Inhibitors for the Treatment of Glioblastoma

Glioblastoma (GBM) cancer stem cells (CSCs) contribute to tumor recurrence, treatment resistance, and dismal clinical outcomes. Genetic and pharmacological evidence suggests that the nuclear scaffolding protein WD-repeat containing protein 5 (WDR5) is a therapeutic vulnerability of the CSC population. However, previously reported WDR5 inhibitors display low permeability and are unable to penetrate the blood-brain barrier (BBB), limiting their utility in GBM. Herein, we report the structure-guided development of a novel series of triazole-based WDR5 WIN-site inhibitors designed to increase passive brain penetration. We identified triazole-based WDR5 inhibitors that are potent, passively permeable, and in some cases more brain penetrant than other scaffolds. We phenotypically assessed our novel WDR5 inhibitors in a panel of patient-derived CSC models and uncovered unique WDR5-regulated metabolic genes in GBM. We also evaluated their antiproliferative activity against CSCs both in vitro and in vivo. Finally, to identify novel combination opportunities, we screened a 2,100-compound chemical probe library and identified that the ATAD2 inhibitor BAY-850 synergizes with WDR5 inhibitors to enhance CSC killing. Our work diversifies the chemical matter targeting WDR5, clarifies the in vitro consequences of WIN-site inhibition in CSCs, and encourages the future development of next-generation WDR5 inhibitors with the potential to achieve in vivo efficacy in the brain.

cancer biology↗