Biology subjects

Verstraelen, P.

Publications and source records attributed to Verstraelen, P..

6 recordsLinked to original sources

bioRxiv2025

KCNQ2 Loss-of-Function variants disrupt neuronal maturation via early hyperexcitability followed by maladaptive network remodeling

Loss-of-function (LOF) variants in the potassium channel subunit KCNQ2 cause a spectrum of neonatal epilepsies from self-limiting familial neonatal epilepsy (SeLFNE) to severe developmental and epileptic encephalopathy (DEE). To dissect the developmental consequences of KCNQ2 LOF, we conducted a longitudinal and multimodal comparative analysis in a human neuronal model generated from patients with KCNQ2-DEE and KCNQ2-SeLFNE. KCNQ2-LOF induced a biphasic network dysfunction, with early Kv7-driven hyperexcitability rescued by acute Retigabine (RTG) treatment, followed by maladaptive remodeling in the opposite direction. Transcriptomic analysis mirrored this biphasic dynamic trajectory, revealing an initial upregulation followed by a subsequent downregulation of synaptic genes. Structural analysis showed a steeper decline in presynaptic density alongside a distal shift in the axon initial segment (AIS) throughout maturation, and impaired AIS plasticity at later stages. Overall, KCNQ2-LOF disrupts human neuronal maturation through dynamic, biphasic changes in function, gene expression and structure, offering insights into disease mechanisms and therapeutic options.

neuroscience↗

bioRxiv2025

DRP1 depletion protects NK cells against hypoxia-induced dysfunction

Hypoxia within the tumor microenvironment poses a major barrier to the efficacy of NK cell-based immunotherapies for solid tumors. In this study, we investigated the influence of hypoxia on NK cell function and mitochondria. We found that hypoxia reduced NK cell cytotoxicity, mitochondrial content, and membrane potential, while increasing mtROS and inducing broad transcriptional changes in metabolic and stress response pathways. CAR engineering with CD70 and IL-15, while designed to enhance persistence and metabolic fitness, did not prevent hypoxia-induced impairment. Given the mitochondrial disruption, we then explored whether DRP1 ablation could mitigate hypoxia-induced dysfunction. Pharmacological inhibition of DRP1 restored mitochondrial content and cytotoxic function. To confirm the role of DRP1, we generated CRISPR-Cas9-mediated DRP1 KO NK cells, which preserved mitochondrial load and membrane potential under hypoxia. When armed with CD70-CAR-IL-15, DRP1KO cells retained cytotoxic activity under hypoxic conditions. These findings show that DRP1 inactivation can support NK cell function in hypoxic environments, and that metabolic engineering may enhance CAR NK cell efficacy in solid tumors. Graphical abstractNK cells become dysfunctional in hypoxic conditions, while DRP1KO NK cells retain their function. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=149 SRC="FIGDIR/small/661011v2_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@2c3a96org.highwire.dtl.DTLVardef@1ba7d20org.highwire.dtl.DTLVardef@6ceeecorg.highwire.dtl.DTLVardef@1b9e0ca_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2023

S100A8-enriched microglia populate the brain of tau-seeded and accelerated aging mice

Long considered to fluctuate between pro- and anti-inflammatory states, it has now become evident that microglia occupy a variegated phenotypic landscape with relevance to aging and neurodegeneration. However, whether specific microglial subsets converge in or contribute to both processes that eventually affect brain function is less clear. To investigate this, we analyzed microglial heterogeneity in a tauopathy mouse model (K18-seeded P301L) and an accelerated aging model (senescence accelerated mouse prone 8, SAMP8) using cellular indexing of transcriptomes and epitopes by sequencing. We found that widespread tau pathology in K18-seeded P301L mice caused a significant change in the number and morphology of microglia, but only a mild overrepresentation of disease-associated microglia. At the cell population-level, we observed a marked upregulation of the calprotectin-encoding genes S100a8 and S100a9. In 9-months-old SAMP8 mice, we identified a unique microglial subpopulation that showed partial similarity with the disease-associated microglia phenotype and was additionally characterized by a high expression of the same calprotectin gene set. Immunostaining for S100A8 revealed that this population was enriched in the hippocampus, correlating with the cognitive impairment observed in this model. However, incomplete colocalization between their residence and markers of neuronal loss suggests regional specificity. Importantly, S100A8-positive microglia were also retrieved in brain biopsies of human AD and tauopathy patients as well as in a biopsy of an aged individual without reported pathology. Thus, the emergence of S100A8-positive microglia portrays a conspicuous commonality between accelerated aging and tauopathy progression, which may have relevance for ensuing brain dysfunction. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=162 SRC="FIGDIR/small/566543v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@d1e4e1org.highwire.dtl.DTLVardef@98adeorg.highwire.dtl.DTLVardef@7c15aaorg.highwire.dtl.DTLVardef@7265ca_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2022

Enteric glia adopt an activated pro-inflammatory state in response to human and bacterial amyloids

Mounting evidence suggests a role for the microbiome-gut-brain axis in amyloid-associated neurodegeneration, but the pathogenic changes induced by amyloids in the gastro-intestinal tract remain elusive. To scrutinize the early response to amyloids of human and bacterial origin, we challenged primary murine myenteric networks with A{beta}1-42 (vs a scrambled version of A{beta}1-42) and curli (vs culture medium), respectively, and performed shotgun RNA sequencing. Both amyloid types induced a transcriptional signature of DNA damage and cell cycle dysregulation. Using in vitro neurosphere-derived cultures and in vivo amyloid injections we found that enteric glia and smooth muscle cells were the most responsive cell types, showing increased proliferation, {gamma}H2AX burden and SOD2 levels after amyloid challenge. Consistent with this activated state, we identified a pro-inflammatory hub in the transcriptional profile of amyloid-stimulated myenteric networks. Enteric glia were the principal source of the associated cytokines, and in vivo, this was accompanied by an influx of immune cells. Together, these results shed new light on the intrinsic vulnerability of ENS cells to both amyloid species and position enteric glial cell activation as an early driver of neurodegenerative disease progression. Significance statementThe increasing socio-economic impact of Alzheimers disease (AD), long sub-clinical disease progression window, and failure of drug candidates demand mechanistic insight into the early stages of disease development. Epidemiological associations and experimental studies in rodents suggest that the gut may be vulnerable to amyloids and mediate their transfer to the brain. However, whether and how amyloids induce local pathology in the gastro-intestinal wall is not known. We identified a pathogenic program that becomes activated in the gastro-intestinal tract after exposure to amyloid {beta} and curli (the main bacterial amyloid), and show that enteric glia are responsible for creating an amyloid-induced pro-inflammatory environment. This insight of an early response in a distant, more accessible organ than the brain, may have important implications for both disease diagnosis and therapy.

neuroscience↗

bioRxiv2020

Systematic quantification of synapses in primary neuronal culture

A vast set of neurological disorders is associated with impaired synaptic connectivity. Therefore, modulation of synapse formation could have therapeutic relevance. However, the high density and small size of synapses make their quantification a challenging task. To improve the reliability of synapse-oriented drug screens, we evaluated a panel of synapse-targeting antibodies for their labeling specificity on hippocampal and cortical cell cultures using quantitative immunofluorescence microscopy. For those antibodies that passed multiparametric validation, we assessed pairwise colocalization, an often-used readout for established synapses. We found that even when two pan-synaptic markers were used, the overlap was incomplete, and the presence of spurious signals limited the dynamic range. To circumvent this problem, we implemented a proximity ligation-based approach, that only leads to a signal when two pre- and postsynaptic markers are sufficiently close. We demonstrate that this approach can be applied to different synaptic marker combinations and can be successfully used for quantification of synapse density in cultures of different maturity stage in healthy or pathological conditions. Thus, the unbiased analysis of synapse labeling and exploitation of resident protein proximity, allows increasing the sensitivity of synapse quantifications in neuronal culture and therefore represents a valuable extension of the analytical toolset for in vitro synapse screens.

neuroscience↗

bioRxiv2019

Deep coverage microscopy exposes a pharmacological window for modifiers of neuronal network connectivity

BackgroundTherapeutic developments for neurodegenerative disorders are redirecting their focus to the mechanisms that contribute to synaptic plasticity and the loss thereof. Identification of novel regulators requires a method to quantify neuronal network connectivity with high accuracy and throughput. To meet this demand, we have established a microscopy-based pipeline that integrates morphological and functional correlates of connectivity in primary neuronal culture. ResultsWe unveiled a connectivity signature that was specific to the cell type and culture age. We defined a score that accurately reports on the degree of neuronal connectivity and we validated this score by targeted perturbation of microtubule stability and selective depletion of anti-oxidants. With a focused compound screen, we discovered that inhibition of dual leucine zipper kinase activity increased neuronal connectivity in otherwise unperturbed cultures and exerted neuroprotective effects in cultures grown under sub-optimal or challenged conditions. ConclusionsOur results illustrate that profiling microscopy images with deep coverage enables sensitive interrogation of neuronal connectivity and allows exposing a dose and time window for pharmacological interventions. Therefore, the current approach holds promise for identifying pathways and compounds that preserve or rescue neuronal connectivity in neurodegenerative disorders.

neuroscience↗