Biology subjects

Pauwels, J.

Publications and source records attributed to Pauwels, J..

11 recordsLinked to original sources

bioRxiv2026

TRMT10A deficiency and tRNA fragmentation disrupt human pancreatic β-cell identity and insulin maturation

Mutations in the tRNA-modifying enzyme TRMT10A cause a rare monogenic syndrome characterized by early-onset diabetes and neurodevelopmental defects, yet the molecular mechanisms underlying TRMT10A diabetes remain unclear. Using human TRMT10A-deficient (knockout and mutant) induced pluripotent stem cells (iPSCs) differentiated into islet-like aggregates and TRMT10A-silenced EndoC-{beta}H1 human {beta}-cells, we show that TRMT10A deficiency impairs {beta}-cell differentiation, insulin content and glucose-stimulated insulin secretion while inducing widespread transcriptional alterations. These defects are accompanied by oxidative stress, diminished antioxidant capacity, and defective proinsulin processing driven by reduced PCSK1 expression. Mechanistically, the loss of TRMT10A promotes tRNA fragmentation and the generation of fragments derived from the 5 end of tRNAGln-CTG (tDRGln-CTG) that interact with hnRNPM. Our data support the existence of a previously unrecognized hnRNPM-PTBP1 interaction in human {beta}-cells and suggest that this complex may contribute to the regulation of PCSK1 mRNA stability and/or translation. Furthermore, through its interaction with hnRNPM, tDRGln-CTG may alter the function of the complex thereby contributing to reduced PCSK1 expression, defective proinsulin processing, and impaired insulin content. Our findings link tRNA fragmentation, RNA-binding protein networks and insulin maturation, positioning TRMT10A as a critical regulator of {beta}-cell identity and function and uncovering a novel mechanism of {beta}-cell failure in the pathogenesis of diabetes.

molecular biology↗

bioRxiv2026

DiaReport: Reproducible Workflow for Differential Expression Analysis and Interactive Reporting in DIA-based Proteomics

SummaryData-independent acquisition (DIA) has become the preferred data acquisition method for mass spectrometry-based proteomics, yet, reproducible workflows for differential expression (DE) analysis and reporting results remain limited. We present DiaReport, an R package that performs precursor- and protein-level DE analysis from DIA-NN output using MSqRob and QFeatures, while generating high-quality, interactive HTML reports through Quarto. DiaReport integrates precursor data, filtering of missing values, normalization, protein summarization and statistical modeling within a single function, supporting both simple pairwise as well as complex experimental designs. The package provides structured outputs and configuration files to ensure computational reproducibility across different studies. To accommodate diverse research needs, DiaReport includes multiple reporting templates tailored to different proteomic applications. Applying DiaReport to an extracellular vesicle (EV) proteomics dataset demonstrates its ability to efficiently analyze DIA data and provide rapid insights into sample quality and protein level differences. Availability and ImplementationDiaReport is an open-source R package available at https://github.com/Gevaert-Lab/diareport. The package is platform-independent and distributed under the MIT license. Reports are generated using Quarto and require only standard R dependencies. Detailed documentation, installation guides and usage vignettes are provided within the repository. The interactive HTML reports discussed in this study, including the UPS2 benchmark and EV case study, are archived on Zenodo (https://doi.org/10.5281/zenodo.18632744 and https://doi.org/10.5281/zenodo.18632731). ContactCorresponding author: Kris Gevaert; kris.gevaert@vib-ugent.be.

bioinformatics↗

bioRxiv2025

A 96well ultrafiltration approach for the high-throughput proteome analysis of extracellular vesicles isolated from conditioned medium

1.Extracellular vesicles (EVs), nanoscale vesicles that are secreted by cells, are critical mediators of intercellular communication and play a crucial role in diverse pathologies such as cancer development. Therefore, EVs are regarded as having high potential in the clinic, both for diagnostic and therapeutic applications. Unfortunately, EVs reside in complex biofluids and their consistent isolation at sufficient purity for mass spectrometry-based proteomics has proven to be challenging, especially when increased high-throughput is required. Here, we describe the incorporation of our previously reported filter-aided EV enrichment (FAEVEr) strategy for the isolation of EVs from conditioned medium, from harvest to proteomic analysis completely to a streamlined 96well format. We compared our approach with ultracentrifugation, the most widely used method for EV enrichment, in terms of protein identifications, consistency, reproducibility and overall performance, including the invested time, resources and required expertise. In addition, our results show that including relative high percentages of TWEEN-20, a mild detergent, markedly improves the final purity of the EV proteome by removing the bulk of non-EV proteins (e.g. serum proteins) and significantly increases the number of identified transmembrane proteins. Moreover, our FAEVEr 96well strategy improves the overall reproducibility with a consistent number of protein identifications and decreased number of missing values across replicates. This promotes the validity and comparability between results, which is essential in both a clinical and research setting, where consistency is paramount. 3. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/634668v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@b45d01org.highwire.dtl.DTLVardef@1460cd0org.highwire.dtl.DTLVardef@1f345fcorg.highwire.dtl.DTLVardef@77c223_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2024

High-throughput nano-flow proteomics using a dual-column electrospray source

With current trends in proteomics, especially regarding clinical and low input (to single cell) samples, it is increasingly important to both maximize the throughput of the analysis and maintain as much sensitivity as possible. The new generation of mass spectrometers (MS) are taking a huge leap in sensitivity, allowing to analyze samples with shorter liquid chromatography (LC) methods while digging as deep in the proteome. However, the throughput can be doubled by implementing a dual column nano-LC-MS configuration. For this purpose, we used a dual-column setup with a two-outlet electrospray source, and compared it to a classic dual-column setup with a single-outlet source.

biochemistry↗

bioRxiv2023

Filter-aided extracellular vesicle enrichment (FAEVEr)

AbstractExtracellular vesicles (EVs), membrane-delimited nanovesicles that are secreted by cells into the extracellular environment, are gaining substantial interest due to their involvement in cellular homeostasis and their contribution to disease pathology. The latter in particular has led to an exponential increase in interest in EVs as they are considered to be circulating packages containing potential biomarkers and are also a possible biological means to deliver drugs in a cell-specific manner. However, several challenges hamper straightforward proteome analysis of EVs as they are generally low abundant and reside in complex biological matrices. These matrices typically contain abundant protein concentrations that vastly exceed those of the EV proteome. Therefore, extensive EV isolation and purification protocols are imperative and many have been developed, including (density) ultracentrifugation, size-exclusion and precipitation methods. Here, we describe filter-aided extracellular vesicle enrichment (FAEVEr) as an approach based on 300 kDa MWCO filtration that allows the processing of multiple samples in parallel within a reasonable timeframe and at moderate cost. We demonstrate that FAEVEr is capable of quantitatively retaining EV particles on filters, whilst allowing extensive washing with the mild detergent TWEEN-20 to remove interfering non-EV proteins. The retained particles are directly lysed on the filter for a complete recovery of the EV protein cargo towards proteome analysis. Here, we validate and optimize FAEVEr on recombinant EV material and apply it on conditioned medium as well as on complex serum. Our results indicate that EVs isolated from MCF7 cells cultured with or without serum have a drastic different proteome because of nutrient deprivation.

cell biology↗

bioRxiv2023

Aberrant phase separation is a common killing strategy of positively charged peptides in biology and human disease

Positively charged repeat peptides are emerging as key players in neurodegenerative diseases. These peptides can perturb diverse cellular pathways but a unifying framework for how such promiscuous toxicity arises has remained elusive. We used mass-spectrometry-based proteomics to define the protein targets of these neurotoxic peptides and found that they all share similar sequence features that drive their aberrant condensation with these positively charged peptides. We trained a machine learning algorithm to detect such sequence features and unexpectedly discovered that this mode of toxicity is not limited to human repeat expansion disorders but has evolved countless times across the tree of life in the form of cationic antimicrobial and venom peptides. We demonstrate that an excess in positive charge is necessary and sufficient for this killer activity, which we name polycation poisoning. These findings reveal an ancient and conserved mechanism and inform ways to leverage its design rules for new generations of bioactive peptides.

cell biology↗

bioRxiv2022

Mutation of Arabidopsis SME1 and Sm core assembly improves oxidative stress resilience

Alternative splicing is a key posttranscriptional gene regulatory process, acting in diverse adaptive and basal plant processes. Splicing of precursor-messenger RNA (pre-mRNA) is catalyzed by a dynamic ribonucleoprotein complex, designated the spliceosome. In a suppressor screen, we identified a nonsense mutation in the Sm protein SME1 to alleviate photorespiratory H2O2-dependent cell death in catalase deficient plants. Similar attenuation of cell death was observed upon chemical inhibition of the spliceosome, suggesting pre-mRNA splicing inhibition to be responsible for the observed cell death alleviation. Furthermore, the sme1-2 mutants showed increased tolerance to the reactive oxygen species inducing herbicide methyl viologen. Both an mRNA-seq and shotgun proteomic analysis in sme1-2 mutants displayed a constitutive molecular stress response, together with extensive alterations in pre-mRNA splicing of transcripts encoding metabolic enzymes and RNA binding proteins, even under unstressed conditions. Using SME1 as a bait to identify protein interactors, we provide experimental evidence for almost 50 homologs of mammalian spliceosome-associated protein to reside in the Arabidopsis thaliana spliceosome complexes and propose roles in pre-mRNA splicing for four uncharacterized plant proteins. Furthermore, like in sme1-2, a mutant in the Sm core assembly protein ICLN resulted in a decreased sensitivity to methyl viologen. Taken together, these data show that both a perturbed Sm core composition and assembly results in the activation of a defense response and enhanced resilience to oxidative stress.

plant biology↗

bioRxiv2021

Proteome-wide cellular thermal shift assay reveals novel crosstalk between brassinosteroid and auxin signaling

Despite the growing interest in using chemical genetics in plant research, small-molecule target identification remains a major challenge. The cellular thermal shift assay coupled with high-resolution mass-spectrometry (CETSA MS) that monitors changes in the thermal stability of proteins caused by their interactions with small molecules, other proteins, or post-translational modifications allows the identification of drug targets, or the study of protein-metabolite and protein-protein interactions mainly in mammalian cells. To showcase the applicability of this method in plants, we applied CETSA MS to intact Arabidopsis thaliana cells and identified the thermal proteome of the plant-specific glycogen synthase kinase 3 (GSK3) inhibitor, bikinin. A comparison between the thermal- and the phospho-proteomes of bikinin revealed the auxin efflux carrier PIN-FORMED1 (PIN1) as a novel substrate of the Arabidopsis GSK3s that negatively regulate the brassinosteroid signaling. We established that PIN1 phosphorylation by the GSK3s is essential for maintaining its intracellular polarity that is required for auxin-mediated regulation of vascular patterning in the leaf thus, revealing a novel crosstalk between brassinosteroid and auxin signaling. Significance StatementChemical genetics, which investigates the biological processes using small molecules, is gaining interest in plant research. However, a major challenge is to uncover the mode of action of the small molecule. Here, we applied the cellular thermal shift assay coupled with mass spectrometry (CETSA MS) to intact Arabidopsis cells and showed that bikinin, the plant-specific glycogen synthase kinase 3 (GSK3) inhibitor, changed the thermal stability of some of its direct targets and putative GSK3 interacting proteins. In combination with phosphoproteomics, we also revealed that GSK3s phosphorylate the auxin carrier PIN-FORMED1 (PIN1) and regulated its polarity that is required for the vascular patterning in the leaf.

plant biology↗

bioRxiv2019

A simple approach for accurate peptide quantification in MS-based proteomics

Despite its growing popularity and use, bottom-up proteomics remains a complex analytical methodology. Its general workflow consists of three main steps: sample preparation, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and computational data analysis. Quality assessment of the different steps and components of this workflow is instrumental to identify technical flaws and to avoid loss of precious measurement time and sample material. However, assessment of the extent of sample losses along the sample preparation protocol, in particular after proteolytic digestion, is not yet routinely implemented because of the lack of an accurate and straightforward method to quantify peptides. Here, we report on the use of a microfluidic UV/visible spectrophotometer to quantify MS-ready peptides directly in MS loading solvent, consuming only 2 l of sample. We determined the optimal peptide amount for LC-MS/MS analysis on a Q Exactive HF mass spectrometer using a dilution series of a commercial K562 cell digest. Careful evaluation of selected LC and MS parameters allowed us to define 3 g as an optimal peptide amount to be injected on this particular LC-MS/MS system. Finally, using tryptic digests from human HEK293T cells, we showed that injecting equal peptide amounts, rather than approximated ones, results into less variable LC-MS/MS and protein quantification data. The obtained quality improvement together with easy implementation of the approach makes it possible to routinely quantify MS-ready peptides as a next step in daily proteomics quality control.

biochemistry↗

bioRxiv2018

Digging deeper into the human proteome: A novel nanoflow LCMS setup using micro pillar array columns (μPAC™)

In bottom-up proteomics, capillaries up to 75 cm long with internal diameters of 50 to 100 {micro}m packed with sub-2-{micro}m C18-functionalized particles are routinely used in combination with high-resolution mass spectrometry. Unlike such conventional liquid chromatography (LC) columns, micro pillar array columns ({micro}PAC) are fabricated using micromachining technology, resulting in perfectly ordered chromatographic separation beds, leading to a minimized analyte dispersion while column permeability is increased by one order of magnitude. This allows using very long columns (up to 200 cm) at only a fraction of the pressure needed to operate packed bed columns. To validate {micro}PAC column performances, different amounts of tryptic digests of HEK293T cell lysates were prepared and separated using a 200 cm {micro}PAC column or a 40 cm long conventional column. Using an Orbitrap Elite instrument, on average 25% more proteins were identified with the {micro}PAC column. Moreover, the rate at which the peak width increases with gradient time is much lower on the {micro}PAC column. For a 10-hour long gradient, average peak widths below 0.5 min were observed, resulting in consistent identification of over 5,000 proteins. Combining long solvent gradients and this new type of LC column, substantial improvements in proteome coverage could be obtained. Finally, we demonstrated high reproducibility and durability of the {micro}PAC column. Data are available via ProteomeXchange with identifiers PXD011547 and PXD013235.

biochemistry↗

bioRxiv2018

A well-controlled BioID design for endogenous bait proteins.

The CRISPR/Cas9 revolution is profoundly changing the way life sciences technologies are used. Many assays now rely on engineered clonal cell lines to eliminate overexpression of bait proteins. Control cell lines are typically non-engineered cells or engineered clones implying a considerable risk for artefacts because of clonal variation. Genome engineering can also transform BioID, a proximity labelling method that relies on fusing a bait protein to a promiscuous biotin ligase, BirA*, resulting in the tagging of vicinal proteins. We here propose an innovative design to enable BioID for endogenous proteins wherein we introduce a T2A-BirA* module at the C-terminus of endogenous p53 by genome engineering, leading to bi-cistronic expression of both p53 and BirA* under control of the endogenous promoter. By targeting a Cas9-cytidine deaminase base editor to the T2A auto-cleavage site, we can efficiently derive an isogenic population expressing a functional p53-BirA* fusion protein. Using quantitative proteomics we show significant benefits over classical ectopic expression of p53-BirA*, and we provide a first well-controlled view on the proximal proteins of endogenous p53 in colon carcinoma cells. This novel application for base editors expands the CRISPR/Cas9 toolbox and can be a valuable addition for synthetic biology.\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=142 SRC=\"FIGDIR/small/427807v2_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (20K):\norg.highwire.dtl.DTLVardef@404da1org.highwire.dtl.DTLVardef@1a8af36org.highwire.dtl.DTLVardef@18741a6org.highwire.dtl.DTLVardef@e73ab3_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗