Biology subjects

Schoels, L.

Publications and source records attributed to Schoels, L..

4 recordsLinked to original sources

bioRxiv2026

Deep axonal proteomics of human iPSC-derived neurons by microfluidic separation and DIA-MS

One of the defining features of neurons is their compartmentalisation into soma, dendrites and axon. Axons are highly specialised for the transmission of signals over long distances but also exhibit unique vulnerabilities in the context of neurodegeneration, implying a specialised axonal proteome. However, in-depth proteomic characterisation of axons has been limited by the difficulty of isolating pure axonal material in sufficient quantities for conventional mass spectrometry analysis. Here, we combine microfluidic-based axon-soma separation with data-independent acquisition mass spectrometry (DIA-MS) on an Orbitrap Astral mass spectrometer for deep profiling of compartment-resolved proteomes of human induced pluripotent stem cell (iPSC)-derived cortical neurons. We quantify over 9,000 proteins in the somatodendritic compartment and [~]6,000 proteins in the axonal compartment, to our knowledge, representing the deepest human axonal proteome reported to date. Differential abundance analysis identifies 1,250 axon-enriched proteins with strong enrichment of axon-related pathways including vesicle-mediated transport, synaptic vesicle dynamics, and cytoskeletal organisation. Extending this workflow to iPSC-derived lower motor neurons, we reveal a core set of 417 axon-enriched proteins shared between cortical and lower motor neurons, alongside subtype-specific axonal signatures whose functional differences become evident only through compartment-restricted analysis. We show broad coverage of genes for the neurodegenerative diseases hereditary spastic paraplegia and amyotrophic lateral sclerosis, establishing a quantitative reference for interpreting how disease-linked mutations may differentially affect axonal versus somatodendritic proteostasis. This workflow and resource are readily applicable to other neuronal subtypes and disease models, paving the way for studying axonal proteome dynamics in health and disease. HighlightsO_LIDeepest human axonal proteome with [~]6,000 proteins from iPSC-derived neurons C_LIO_LIMicrofluidic separation paired with DIA mass spectrometry C_LIO_LIAxon-specific signatures masked in whole-cell analyses are revealed C_LIO_LICore set of 417 axon-enriched proteins shared across neuron subtypes C_LIO_LIFramework for studying axon-selective vulnerability in neurodegeneration C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=74 SRC="FIGDIR/small/739061v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@191493dorg.highwire.dtl.DTLVardef@15f459forg.highwire.dtl.DTLVardef@1d3e61forg.highwire.dtl.DTLVardef@a9262a_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Unraveling Axonal Transcriptional Landscapes: Insights from iPSC-Derived Cortical Neurons and Implications for Motor Neuron Degeneration

Neuronal function and pathology are deeply influenced by the distinct molecular profiles of the axon and soma. Traditional studies have often overlooked these differences due to the technical challenges of compartment specific analysis. In this study, we employ a robust RNA-sequencing (RNA-seq) approach, using microfluidic devices, to generate high-quality axonal transcriptomes from iPSC-derived cortical neurons (CNs). We achieve high specificity of axonal fractions, ensuring sample purity without contamination. Comparative analysis revealed a unique and specific transcriptional landscape in axonal compartments, characterized by diverse transcript types, including protein-coding mRNAs, RNAs encoding ribosomal proteins (RPs), mitochondrial-encoded RNAs, and long non-coding RNAs (lncRNAs). Previous works have reported the existence of transcription factors (TFs) in the axon. Here, we detect a set of TFs specific to the axon and indicative of their active participation in transcriptional regulation. To investigate transcripts and pathways essential for central motor neuron (MN) degeneration and maintenance we analyzed KIF1C-knockout (KO) CNs, modeling hereditary spastic paraplegia (HSP), a disorder associated with prominent length-dependent degeneration of central MN axons. We found that several key factors crucial for survival and health were absent in KIF1C-KO axons, highlighting a possible role of these also in other neurodegenerative diseases. Taken together, this study underscores the utility of microfluidic devices in studying compartment-specific transcriptomics in human neuronal models and reveals complex molecular dynamics of axonal biology. The impact of KIF1C on the axonal transcriptome not only deepens our understanding of MN diseases but also presents a promising avenue for exploration of compartment specific disease mechanisms.

neuroscience↗

bioRxiv2022

Human organoid model of PCH2a recapitulates brain region-specific pathology

Pontocerebellar hypoplasia type 2 a (PCH2a) is a rare, autosomal recessive pediatric disorder with limited treatment options. Its anatomical hallmark is the hypoplasia of the cerebellum and pons accompanied by progressive microcephaly. PCH2a results from a homozygous founder variant in TSEN54, which encodes a tRNA splicing endonuclease (TSEN) complex subunit. Despite the ubiquitous expression of the TSEN complex, the tissue-specific pathological mechanism of PCH2a remains unknown due to a lack of model system. In this study, we developed human models of PCH2a using brain region-specific organoids. We therefore obtained skin biopsies from three affected males with genetically confirmed PCH2a and derived induced pluripotent stem cells (iPSCs). Proliferation and cell death rates were not altered in PCH2a iPSCs. We subsequently differentiated cerebellar and neocortical organoids from control and PCH2a iPSCs. Mirroring clinical neuroimaging findings, PCH2a cerebellar organoids were reduced in size compared to controls starting early in differentiation. We observed milder growth deficits in neocortical PCH2a organoids. While PCH2a cerebellar organoids did not upregulate apoptosis, their stem cell zones showed altered proliferation kinetics, with increased proliferation at day 30 and reduced proliferation at day 50 compared to controls. In summary, we have generated a human model of PCH2a, which provides the foundation for deciphering brain region-specific disease mechanisms.

neuroscience↗

bioRxiv2021

Turning movements in real life capture subtle longitudinal and preataxic changes in cerebellar ataxia

OBJECTIVESClinical and regulatory acceptance of upcoming molecular treatments in degenerative ataxias might greatly benefit from ecologically valid endpoints which capture change in ataxia severity in patients real life. This longitudinal study aimed to unravel quantitative motor biomarkers in degenerative ataxias in real life turning movements which are sensitive for changes both longitudinally and at the preataxic stage. METHODSCombined cross-sectional (n=30) and longitudinal (n=14, 1-year interval) observational study in degenerative cerebellar disease (including 8 pre-ataxic mutation carriers) compared to 23 healthy controls. Turning movements were assessed by three body-worn inertial sensors in three conditions: (1) instructed laboratory assessment, (2) supervised free walking, and (3) unsupervised real-life movements. RESULTSMeasures which quantified dynamic balance during turning - lateral velocity change (LVC) and outward acceleration -, but not general turning measures such as speed, allowed differentiating ataxic against healthy subjects in real life with high effect size ({delta}=0.68), with LVC also differentiating preataxic against healthy subjects ({delta}=0.53). LVC was highly correlated with clinical ataxia severity (SARA score, effect size {rho}=0.79) and subjective balance confidence (ABC score, {rho}=0.66). Moreover, LVC in real life - but not general turning measures, gait measures, or the SARA score - allowed detecting significant longitudinal change in one-year follow-up with high effect size (rprb=0.66). CONCLUSIONSMeasures of turning allow to capture specific changes of dynamic balance in degenerative ataxia in real life, with high sensitivity to longitudinal differences in ataxia severity and to the preataxic stage. They thus present promising ecologically valid motor biomarkers for capturing change in real life, even in the highly treatment-relevant early stages of degenerative cerebellar disease.

bioengineering↗