Biology subjects

van den Biggelaar, M.

Publications and source records attributed to van den Biggelaar, M..

6 recordsLinked to original sources

bioRxiv2025

Proximity labeling reveals ZFP36L1 as a central hub for post-transcriptional regulation networks in T cells

Effective T cell responses against pathogens require a rapid yet tightly controlled remodeling of the proteome, and RNA binding proteins (RBPs) are key in this process. For instance, the RBP ZFP36L1 prevents excessive protein production and thereby limits immunopathology. ZFP36L1 is primarily known to mediate mRNA decay, but it can also regulate other processes. How its mode of action relates to its interaction partners is, however, not well-understood. Here, we mapped the ZFP36L1 interactome in primary human T cells. Using proximity labeling, we identified known and new interactors that regulate 3UTR-mediated RNA degradation, deadenylation, stress granule/p-body formation, as well as 5UTR-mediated translation repression and mRNA decapping. Snapshot analysis uncovered the ZFP36L1 interactome dynamics and RNA (in)dependency throughout T cell activation. Intriguingly, proximity labeling also uncovered regulators of ZFP36L1 protein expression: This included the helicase UPF1, which not only interacts with ZFP36L1 protein but also promotes its protein expression. Altogether, this comprehensive interactome map underlines the versatility of interactions with ZFP36L1 and their possible role in cellular function.

molecular biology↗

bioRxiv2025

Transcriptome-Proteome analysis of human naive and memory B cell subsets reveal isotype and subclass-specific phenotypes

Antibodies produced by B cells aid in recognition and clearance of pathogens and is the cornerstone of vaccination strategies. Humans produce nine different antibody isotypes and their effector functions differ according to the type of antigen and route of exposure. Phenotypic variation between isotype-switched B cell subsets is expected but not studied in detail. To obtain a molecular definition of isotype-defined cell identity, we performed proteomics and transcriptomics on isotype-defined populations of human naive and memory B cells (MBCs): CD27-IgM+IgD+, CD27+CD38lo/-IgM+IgD+, CD27+CD38lo/-IgM+IgD-, and IgA1, IgA2, IgG1, IgG2, IgG3, and IgG4 MBCs (CD27+CD38lo/-Ig+). Combined proteome and transcriptome analysis revealed that mRNA and protein expression profiles separate isotype-defined B cell subsets according to their differentiation status. mRNA and protein expression levels correlated reasonably well for many genes. IgG4-switched B cells were most distinct from naive B cells in terms of mRNA as well as protein expression profiles. Besides a distinct expression profile of cytokine and Fc receptors, we identified a high expression of IgE-coding mRNA in IgG4-switched B cells. SDR16C5 was identified as uniquely upregulated in IgG4-switched B cells. Taken together, this study highlights the distinct phenotypic profile of IgG4-switched B cells.

immunology↗

bioRxiv2021

Syntaxin 5 determines Weibel-Palade body size and Von Willebrand factor secretion by controlling Golgi architecture

Von Willebrand factor (VWF) is a multimeric hemostatic protein primarily synthesized in endothelial cells (ECs). VWF is stored in endothelial storage organelles, the Weibel-Palade bodies (WPBs), whose biogenesis strongly depends on VWF anterograde trafficking and Golgi architecture. Elongated WPB morphology is correlated to longer VWF strings with better adhesive properties. We previously identified the SNARE SEC22B, which is involved in anterograde ER-to-Golgi transport, as a novel regulator of WPB elongation. To elucidate novel determinants of WPB morphology we explored endothelial SEC22B interaction partners in a mass spectrometrybased approach, identifying the Golgi SNARE Syntaxin 5 (STX5). We established STX5 knockdown in ECs using shRNA-dependent silencing and analyzed WPB and Golgi morphology, using confocal and electron microscopy. STX5-depleted ECs exhibited extensive Golgi fragmentation and decreased WPB length, which was associated with reduced intracellular VWF levels, and impaired stimulated VWF secretion. However, the secretion-incompetent organelles in shSTX5 cells maintained WPB markers such as Angiopoietin 2, P-selectin, Rab27A, and CD63. Taken together, our study has identified SNARE protein STX5 as a novel regulator of WPB biogenesis.

cell biology↗

bioRxiv2021

Time-dependent regulation of cytokine production by RNA binding proteins defines T cell effector function

Potent T cell responses against infections and malignancies depend on the release of effector molecules, such as pro-inflammatory cytokines. Because effector molecules can be toxic, their production is tightly regulated through post-transcriptional events at 3 Untranslated Regions (3UTRs). RNA binding proteins (RBPs) were shown to be key regulators herein. With an RNA aptamer-based capture assay from human T cells, we identified >130 RBPs interacting with the IFNG, TNF and IL2 3UTRs in human T cells. T cell activation altered RBP-RNA interactions, revealing that RBP-target mRNA interactions rapidly respond to stimulation. Furthermore, we uncovered the intricate and time-dependent regulation of cytokine production by RBPs: whereas HuR supports early cytokine production, ZFP36L1, ATXN2L and ZC3HAV1 dampen and shorten the production duration, each at different time points. Strikingly, even though ZFP36L1 deletion did not phenotypically rescue T cell dysfunction in tumors, the increased production of cytokines and cytotoxic molecules resulted in superior anti-tumoral T cell responses in vivo. Our findings thus show that identifying RBP-RNA interactions reveals key modulators of T cell responses in health and disease.

immunology↗

bioRxiv2021

The relationship between human thymus-derived regulatory T cells, TGF-β-induced regulatory T cells and conventional CD4+ T cells as revealed by proteomics

The CD4+ regulatory T (Treg) cell lineage, as defined by FOXP3 expression, comprises thymus-derived (t)Treg cells and peripherally induced (p)Treg cells. In human, naive tTreg cells can be isolated from blood, while effector tTreg and pTreg cells cannot be purified reliably for lack of cell surface markers. As a model for Treg cells, studies often employ TGF-{beta}-induced (i)Treg cells generated from CD4+ conventional T (Tconv) cells in vitro. Here, we describe the relationship of iTreg cells to tTreg and Tconv cells, as optimally purified from human blood. Proteomic analysis revealed that each of these cell populations has a unique protein expression pattern before and after CD3/CD28-mediated activation. iTreg cells had limited overlap in protein expression with tTreg cells and exhibited markedly differential expression of proteins involved in signal transduction and metabolism. Whereas iTreg and Tconv cells responded strongly to CD3/CD28-mediated activation, tTreg cells showed a modest response, which reflects their adaptations in signal transduction pathways. As a benchmark, we used a previously defined proteomic signature that discerns ex vivo naive and effector Treg cells from Tconv cells and includes conserved Treg cell properties. This Treg cell core signature was largely absent in iTreg cells, as exemplified by STAT4 expression that may contribute to pro-inflammatory functions. In addition, we used a proteomic signature that distinguishes ex vivo effector Treg cells from Tconv cells and naive Treg cells. This effector Treg cell signature was partially present in iTreg cells, indicating that they do have protein expression features in common with ex vivo effector Treg cells. In conclusion, iTreg cells are distinct from tTreg cells and largely lack the Treg cell core proteomic signature, indicating that caution is warranted when using iTreg cells as a model for Treg cell populations found in vivo.

immunology↗

bioRxiv2019

CD29 marks superior cytotoxic human T cells

Cytotoxic CD8+ T cells can effectively kill target cells by producing cytokines, chemokines and granzymes. Expression of these effector molecules is however highly divergent, and tools that identify and pre-select potent killer cells are lacking. Human CD8+ T cells can be divided into IFN-{gamma} and IL-2 producing cells. Unbiased RNA-sequencing and proteomics analysis on cytokine-producing fixed cells revealed that IL-2+ T cells produce helper cytokines, and that IFN-{gamma}+ T cells produce cytotoxic molecules. IFN-{gamma}+ T cells could be identified with the surface marker CD29 already prior to stimulation. CD29 also marked T cells with cytotoxic gene expression from different tissues in single-cell RNA-sequencing data. Notably, the cytotoxic features of CD29+ T cells were maintained during cell culture, suggesting a stable phenotype. Pre-selecting CD29-expressing MART1 TCR-engineered T cells potentiated the killing of target cells. We therefore propose that selecting for CD29+ T cells could boost the anti-tumoral activity of T cell therapeutics.

immunology↗