Biology subjects

Green, F.

Publications and source records attributed to Green, F..

5 recordsLinked to original sources

bioRxiv2026

Using a lanthanide tagged nanobody to visualise Glial fibrillary acidic protein by secondary ion mass spectrometry

Lanthanide-labelled antibodies have been widely used for multiplex imaging of proteins directly from tissue using two approaches, imaging mass cytometry (IMC) and variants of secondary ion mass spectrometry (SIMS). Here we show the same approach can be taken using SIMS, but utilising lanthanide-labelled nanobodies instead. Nanobodies offer several advantages over conventional antibodies for antigen tagging, owing to their small size (12-15 kDa), high stability, and solubility. Their reduced molecular size enables greater diffusion through tissue, facilitating access to target sites and allowing them to reach regions that may be less accessible to larger antibodies. This enhanced accessibility can promote more effective localisation and increase binding to target antigens. In the work presented here, we produced a lanthanide-tagged nanobody and assessed its efficacy and compatibility with mass spectrometry imaging (MSI). We showed successful detection of Glial fibrillary acidic protein (GFAP) in tissue by correlating MSI of a lanthanide-tagged anti-GFAP nanobody with immunofluorescence microscopy imaging (IF). The use of nanobodies is an excellent alternative to current antibody tagging methods for SIMS and IMC.

molecular biology↗

bioRxiv2025

Hypoxia induced lipid alterations in iPSC-derived human glial progenitor cells revealed by Matrix assisted laser desorption ionization mass spectrometry based cellular fingerprinting

BackgroundIncreasing evidence suggests that the development of highly aggressive form of brain tumor "glioblastoma" contain cancer stem cells that closely resemble glial progenitor cells. The hypoxic microenvironment of tumors leads to metabolic reprogramming of cells, driving them towards more aggressive and treatment resistant state. To identify better targets for the effective removal of hypoxia adaptive cells, it is crucial to understand how these cells alter metabolism in hypoxic conditions. MethodsWe have used confocal microscopy to visualize mitochondrial morphology which confirmed hypoxia, and matrix assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) to decipher lipid metabolic changes in iPSC-derived human glial progenitor cells induced by that hypoxia. ResultsOur findings revealed that hypoxia induced changes in mitochondrial morphology, interaction of mitochondria with lysosomes, and the expression of oxidized lipid species in iPSC-derived human glial progenitor cells. Hypoxic cells showed elongated mitochondria that resembled strings. MALDI-MSI based finger printing showed upregulation of oxidized phosphatidylethanolamine (PE): m/z 716.484 PE(33:1)+O, m/z 730.01 PE(34:1)+O, m/z 766.497 PE(37:5)+O, m/z 768.510 PE(37:4)+O, and oxidized phosphatidylcholine (PC): m/z 742.500 PC(32:2)+O, m/z 744.513 PC(33:2)+O, m/z 770.531 PC(34:2)+O), m/z 794.534 PC(34:1)+O, m/z 888.523 PC(42:11)+OH, and oxidized phosphatidic acid (PA): m/z 673.444 PA(33:2)+O, m/z 699.466 PA(35:3)+OH, m/z 725.531 PA(37:4)+OH in hypoxic cells. ConclusionsGiven the importance of glial progenitor cells in the central nervous system, as a precursor of glioblastoma, and their structural reliance on lipids, the molecular perturbations in the cell as a result of oxygen deficiency (hypoxia) remains unclear. The change in mitochondrial morphology showed that the cells were under hypoxic stress and mass spectrometry imaging unveiled important lipid metabolic changes in hypoxic iPSC-derived human glial progenitor cells as byproducts of oxidative stress, and provided insights that could lead to better treatment strategies for hypoxia-resistant cells. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/672639v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@873267org.highwire.dtl.DTLVardef@1fe4810org.highwire.dtl.DTLVardef@12d1aa3org.highwire.dtl.DTLVardef@30048f_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG Graphical abstract was created in BioRender https://app.biorender.com/illustrations/6822efb6aadd8c37669dd403

biochemistry↗

bioRxiv2022

Neural circuit-wide analysis of gene expression during deafening-induced destabilization ofbirdsong

Sensory feedback is required for stable execution of learned motor skills, and its loss can severely disrupt motor performance. The neural mechanisms that mediate sensorimotor stability have been extensively studied at systems and physiological levels, yet relatively little is known about how disruptions to sensory input alter the molecular properties of associated motor systems. Songbird courtship song, a model for skilled behavior, is a learned and highly structured vocalization that is destabilized following deafening. Here, we sought to determine how the loss of auditory feedback modifies gene expression and its coordination across the birdsong sensorimotor circuit. To facilitate this system-wide analysis of transcriptional responses, we developed a gene expression profiling approach that enables the construction of hundreds of spatially-defined RNA-sequencing libraries. Using this method, we found that deafening preferentially alters gene expression across birdsong neural circuitry relative to surrounding areas, particularly in premotor and striatal regions. Genes with altered expression are associated with synaptic transmission, neuronal spines, and neuromodulation and show a bias toward expression in glutamatergic neurons and Pvalb/Sst-class GABAergic interneurons. We also found that connected song regions exhibit correlations in gene expression that were reduced in deafened birds relative to hearing birds, suggesting that song destabilization alters the inter-region coordination of transcriptional state. Finally, lesioning LMAN, a forebrain afferent of RA required for deafening-induced song plasticity, had the largest effect on groups of genes that were also most affected by deafening. Combined, this integrated transcriptomics analysis demonstrates that the loss of peripheral sensory input drives a distributed gene expression response throughout associated sensorimotor neural circuitry and identifies specific candidate molecular and cellular mechanisms that support stability and plasticity of learned motor skills.

neuroscience↗

bioRxiv2020

Ageing compromises mouse thymus function and remodels epithelial cell differentiation

Ageing is characterised by cellular senescence, leading to imbalanced tissue maintenance, cell death and compromised organ function. This is first observed in the thymus, the primary lymphoid organ that generates and selects T cells. However, the molecular and cellular mechanisms underpinning these ageing processes remain unclear. Here, we show that mouse ageing leads to less efficient T cell selection, decreased self-antigen representation and increased T cell receptor repertoire diversity. Using a combination of single-cell RNA-seq and lineage-tracing, we find that progenitor cells are the principal targets of ageing, whereas the function of mature thymic epithelial cells is compromised only modestly. Specifically, an early-life precursor cell population, retained in the mouse cortex postnatally, is virtually extinguished at puberty. Concomitantly, a medullary precursor cell quiesces, thereby impairing maintenance of the medullary epithelium. Thus, ageing disrupts thymic progenitor differentiation and impairs the core immunological functions of the thymus.

immunology↗

bioRxiv2018

The Delirium and Population Health Informatics Cohort study protocol: ascertaining the determinants and outcomes from delirium in a whole population.

BackgroundDelirium affects 25% of older inpatients and is associated with long-term cognitive impairment and future dementia. However, no population studies have systematically ascertained cognitive function before, cognitive deficits during, and cognitive impairment after delirium. Therefore, there is a need to address the following question: does delirium, and its features (including severity, duration, and presumed aetiologies), predict long-term cognitive impairment, independent of cognitive impairment at baseline?\n\nMethodsThe Delirium and Population Health Informatics Cohort (DELPHIC) study is an observational population-based cohort study based in the London Borough of Camden. It is recruiting 2000 individuals aged [≥]70 years and prospectively following them for two years, including daily ascertainment of all inpatient episodes for delirium. Daily inpatient assessments include the Memorial Delirium Assessment Scale, the Observational Scale for Level of Arousal, and the Hierarchical Assessment of Balance and Mobility. Data on delirium aetiology is also collected. The primary outcome is the change in the modified Telephone Interview for Cognitive Status at two years.\n\nDiscussionDELPHIC is the first population sample to assess older persons before, during and after hospitalisation. The cumulative incidence of delirium in the general population aged [≥]70 will be described. DELPHIC offers the opportunity to quantify the impact of delirium on cognitive and functional outcomes. Overall, DELPHIC will provide a real-time public health observatory whereby information from primary, secondary, intermediate and social care can be integrated to understand how acute illness is linked to health and social care outcomes.

epidemiology↗