Biology subjects

Robertson, T.

Publications and source records attributed to Robertson, T..

4 recordsLinked to original sources

bioRxiv2026

Spatial pharmaco-multiomics reveals drug distribution, metabolic niches, and spatially constrained resistance in medulloblastoma

Single-cell and spatial transcriptomic studies have provided insights into the developmental origins and intratumoural heterogeneity of SHH medulloblastoma (SHH-MB) and suggested how targeted drugs such as CDK4/6 inhibitors remodel tumour ecosystems, yet the interplay between local drug exposure, metabolism, cell state, and drug resistance remains poorly understood. Here we developed a same-section spatial pharmaco-multiomics framework that integrates MALDI-MSI-based spatial metabolomics with Visium whole-transcriptome profiling and high-resolution Xenium imaging to map palbociclib distribution, metabolite landscapes, and transcriptional programs within the same histological contexts of an SHH-MB PDOX model and primary human tumours. Palbociclib-rich tumour bulk exhibited broad suppression of E2F-driven proliferation and a shift toward neuronal differentiation, corroborating and extending prior findings. In contrast, drug-poor tumour-brain interfaces and perivascular regions retained E2F-high proliferative states and were enriched for mesenchymal-like stromal cells and ECM-remodelling genes, indicating anatomically constrained reservoirs of tolerance. Spatial metabolomics linked these interface niches to ganglioside (GM2) and sphingomyelin enrichment, while differentiated, drug-exposed regions displayed phosphatidylcholine, phosphatidic-acid signatures consistent with neuronal maturation. Integrated pathway analysis further revealed a "mitochondrial tuning" program, with upregulation of histidine, folate/one-carbon, CoA, and lipoate metabolism with redox and oxidative-phosphorylation support. These signatures were specific to therapy-exposed border cells. Rare palbociclib-positive, E2F-high resistant spots additionally exhibited mitotic checkpoint and DNA-repair signatures, implying a drug-induced resistance axis independent of scarcity. Together, our study provides a generalisable same-section spatial pharmaco-multiomics pipeline and a spatially resolved model of CDK4/6 response, nominating interface-focused metabolic and cell-intrinsic vulnerabilities for combination therapy.

cancer biology↗

bioRxiv2025

Isolation of Extracellular Vesicles from Minimal Volume Ascites Fluid Using Strong Anion Exchange Magnetic Beads

Ovarian cancer (OC) remains a leading cause of gynecologic cancer mortality due to late-stage diagnosis and limited early detection strategies. Ascites fluid, a pathological hallmark of OC, is a rich source of tumor-derived extracellular vesicles (EVs) that reflect the tumor microenvironment and hold promise for biomarker discovery. However, isolating EVs from minimal ascites volumes (<100 {micro}L) poses technical challenges using conventional methods like ultracentrifugation or size-exclusion chromatography (SEC). This study explores the application of strong anion exchange (SAX) magnetic beads (Mag-Net) for efficient EV isolation from as little as 2 {micro}L of ascites fluid from both murine models and a human patient with mucinous borderline tumor. We demonstrate that SAX achieves robust EV capture at 10{micro}l of input volume, enabling comprehensive proteomic profiling and single-EV surface-enhanced Raman spectroscopy (SERS) with a >2-fold increase in proteomic depth compared to raw ascites. Notably, this study was able to identify 1000 proteins not previously annotated in Vesiclepedia for OC-derived EVs, alongside distinct SERS signatures, highlighting the potential for multiomic analysis. Comparative analysis with UC revealed enhanced proteomic depth obtained with SAX beads, albeit we also observed differential detection of canonical markers (e.g., CD9, CD81) between input volumes of ascites fluid. These findings establish SAX as a scalable, low-input platform for EV-based biomarker discovery, paving the way for improved early detection and molecular insights into OC progression.

biochemistry↗

bioRxiv2023

Spatial transcriptomic analysis of Sonic Hedgehog Medulloblastoma identifies that the loss of heterogeneity and promotion of differentiation underlies the response to CDK4/6 inhibition

BackgroundMedulloblastoma (MB) is a malignant tumour of the cerebellum which can be classified into four major subgroups based on gene expression and genomic features. Single cell transcriptome studies have defined the cellular states underlying each MB subgroup, however the spatial organisation of these diverse cell states and how this impacts response to therapy remains to be determined. MethodsHere, we used spatially resolved transcriptomics to define the cellular diversity within a sonic hedgehog (SHH) patient-derived model of MB and identify how cells specific to a transcriptional state or spatial location are pivotal in responses to treatment with the CDK4/6 inhibitor, Palbociclib. We integrated spatial gene expression with histological annotation and single cell gene expression data from MB, developing a analysis strategy to spatially map cell type responses within the hybrid system of human and mouse cells and their interface within an intact brain tumour section. ResultsWe distinguish neoplastic and non-neoplastic cells within tumours and from the surrounding cerebellar tissue, further refining pathological annotation. We identify a regional response to Palbociclib, with reduced proliferation and induced neuronal differentiation in both treated tumours. Additionally, we resolve at a cellular resolution a distinct tumour interface where the tumour contacts neighbouring mouse brain tissue consisting of abundant astrocytes and microglia and continues to proliferate despite Palbociclib treatment. ConclusionsOur data highlight the power of using spatial transcriptomics to characterise the response of a tumour to a targeted therapy and provide further insights into the molecular and cellular basis underlying the response and resistance to CDK4/6 inhibitors in SHH MB.

genomics↗

bioRxiv2021

Biallelic loss-of-function OBSCN variants predispose individuals to severe, recurrent rhabdomyolysis

Rhabdomyolysis is the acute breakdown of skeletal myofibres in response to an initiating factor, most commonly toxins and over exertion. A variety of genetic disorders predispose to rhabdomyolysis through different pathogenic mechanisms, particularly in patients with recurrent episodes. However, the majority of cases remain without a genetic diagnosis. Here we present six patients who presented with severe and recurrent rhabdomyolysis, usually with onset in the teenage years; other features included a history of myalgia and muscle cramps. We identified ten bi-allelic loss-of-function variants in the gene encoding obscurin (OBSCN) co-segregating with disease. We show reduced expression of OBSCN and loss of obscurin protein in patient muscle. Obscurin is proposed to be involved in SR function and Ca2+ handling. Patient cultured myoblasts appear more susceptible to starvation as evidenced by a greater decreased in SR Ca2+ content compared to control myoblasts. This likely reflects a lower efficiency when pumping Ca2+ back into the SR and/or a decrease in Ca2+ SR storage ability when metabolism is diminished. OSBCN variants have previously been associated with cardiomyopathies. None of the patients presented with a cardiomyopathy and cardiac examinations were normal in all cases in which cardiac function was assessed. There was also no history of cardiomyopathy in first degree relatives, in particular in any of the carrier parents. This cohort is relatively young, thus follow-up studies and the identification of additional cases with bi-allelic null OBSCN variants will further delineate OBSCN-related disease and the clinical course of disease.

genetics↗