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de Boer, B.

Publications and source records attributed to de Boer, B..

5 recordsLinked to original sources

Emergent Entrainment and Predictive Dynamics in Bio-Inspired Spiking Neural Networks

Rhythm is a key building block of human music, speech and numerous other human activities. Understanding the computational substrates of rhythm perception requires models that bridge algorithmic function with biological implementation. We propose a physiologically grounded spiking neural network (SNN) framework to investigate the emergent representation and interpretation of auditory rhythms. Utilizing a recurrent SNN architecture trained on an auditory entrainment task, we characterize the networks latent dynamics through the analysis of firing rates and membrane potential fluctuations. Our results demonstrate that simulated neural populations exhibit phase-locking to the stimulus beat, with endogenous oscillations driven by rhythmic input. We further show that anticipatory dynamics--characterized by pre-stimulus depolarization--emerge naturally from the networks synaptic plasticity and temporal integration properties, rather than from explicitly defined oscillators. By treating network layers as functional analogs of cortical populations, this framework allows for the application of spectral and information-theoretic analyses typical of empirical electrophysiology. More in general, this approach establishes SNNs as robust exploratory tools for uncovering how predictive coding and rhythmic entrainment arise from the inherent constraints of biological neural computation.

neuroscience↗

Cholesterol Biosynthesis is a Targetable Vulnerability of CEBPA-mutant Acute Myeloid Leukemia

Bi-allelic CEBPA mutations occur in 5-15% of acute myeloid leukemia (AML) patients. The precise molecular consequences of CEBPA mutations, especially in combination with frequently co-occurring mutations in TET2, WT1, and GATA2, remain incompletely understood. Here, we present a robust human model of CEBPA-mutant AML through gene editing of healthy bone marrow-derived hematopoietic stem cells. Loss of the CEBPA-p42 isoform expressed in healthy cells with concomitant upregulation of the leukemic CEBPA-p30 isoform resulted in a myeloproliferative phenotype. Concurrent loss-of-function mutations in TET2 or WT1 drove full leukemic transformation, while GATA2 haploinsufficiency promoted erythroid precursor accumulation without overt AML. Single-cell transcriptomics and low-input proteomics revealed enhanced myeloid output, increased interferon signaling and elevated cholesterol biosynthesis in leukemic cells. Targeting cholesterol synthesis enhanced chemosensitivity, highlighting a potential therapeutic vulnerability, particularly relevant for CEBPA-mutant patients harboring co-mutations in TET2 or WT1, which have poor outcomes. Statement of significanceInduction of CEBPA-p30 by CRISPR/Cas gene editing in healthy human BM HSCs drives overt AML in vivo. TET2 and WT1 loss accelerate leukemogenesis, while GATA2 haploinsufficiency redirects differentiation toward erythroid precursors potentially driving acute erythroid leukemia. CEBPA-p30 AML exhibits cholesterol biosynthesis dependency, revealing a therapeutic vulnerability to statins.

cancer biology↗

CCL25 targeting by de novo protein binders differentially suppress CCR9 and ACKR4 activation and transform CCL25 into a biased agonist

Chemokines and their receptors mediate cell migration and coordinate immune responses, while dysregulation can lead to inflammation. Therapeutic modulation of the chemokine signaling axis has proven difficult. Most drug discovery efforts target the receptors, whereas natural regulatory mechanisms focus on the chemokines. Despite this insight, development of effective chemokine-directed modulators has remained elusive. Recent advances in de novo protein design offer an unprecedented opportunity to produce high-affinity binders that efficiently block protein-protein interactions. We implemented a computational workflow leveraging the BindCraft platform to generate miniprotein binders against CCL25, the chemokine ligand for the receptors CCR9 and ACKR4 and implicated in inflammatory bowel diseases. The unbiased development results in several miniproteins designed to block the receptor N-terminus from wrapping the chemokine and prevent productive engagement. Thus, these proteins suppress CCL25-mediated effector coupling and halt MOLT-4 lymphoblast migration. Another class of miniprotein, represented by VUP25111, is predicted to bind CCL25 along the chemokine {beta}1 strand and retained receptor binding. This complex inhibited arrestin recruitment to CCR9, but not to ACKR4, indicating receptor specificity. Additionally, G protein signaling through CCR9 was unimpeded by VUP25111, suggesting that the miniprotein biased the native balanced agonist towards G proteins. These results demonstrate the effectiveness of differentially targeting CCL25 to suppress CCR9 signaling and new tools to resolve the structural basis of chemokine receptor activation and bias.

biochemistry↗

Quantitative Label-Free Single-Cell Proteomics on the Orbitrap Astral MS

Single-cell proteomics by mass spectrometry (scp-MS) holds the potential to provide unprecedented insights into molecular features directly linked to the cellular phenotype, while deconvoluting complex organisms into their basic building blocks. Tailored sample preparation that maximizes the extracted amount of material that is introduced into the mass spectrometer has rapidly propelled the field forward. However, the measured signal is still at the lower edge of detection approaching the sensitivity boundary of current instrumentation. Here, we investigate the capacity of the enhanced sensitivity of the Orbitrap Astral mass spectrometer to facilitate deeper proteome profiles from low-input to single-cell samples. We carry out a comprehensive data acquisition method survey to pinpoint which parameters provide most sensitivity. Furthermore, we explore the quantitative accuracy of the obtained measurements to ensure that the obtained abundances are in line with expected ground truth values. We culminate our technical exploration by generating small datasets from two cultured cell lines and a primary bone marrow sample, to showcase obtainable proteome coverage differences from different source materials. Finally, as a proof of concept we explore protein covariation to showcase how information on known protein complexes is captured inherently in our scp-MS data.

biochemistry↗

Evolutionary Dynamics Do Not Motivate a Single-Mutant Theory of Human Language

AbstractOne of the most controversial hypotheses in cognitive science is the Chomskyan evolutionary conjecture that language arose instantaneously in our species as the result of a single staggeringly fortuitous mutation. Here we analyze the evolutionary dynamics implied by this hypothesis, which has never been formalized. The theory supposes the emergence and fixation of a single mutant (capable of the syntactic operation Merge) during a narrow historical window as a result of frequency-independent selection under a huge fitness advantage in a population of an effective size that is standardly assumed to have been no larger than ~15 000 early humans. We examine this proposal by combining diffusion analysis and extreme value theory to derive a probabilistic formulation of its dynamics. Perhaps counter-intuitively, a macro-mutation is much more unlikely a priori than multiple mutations with smaller fitness effects, yet both hypotheses predict fixation with high conditional probability. The consequences of this asymmetry have not been accounted for previously. Our results diffuse any suggestion that evolutionary reasoning provides an independent rationale for the controversial single-mutant theory of language.\n\nSignificance statementIn recent years, Chomsky and colleagues have sought support for their minimalist theory of the language faculty from evolutionary considerations. They have argued for a spontaneous emergence of a mutation conferring an advantage for thought independent of communication. Here for the first time a formalization of this view is offered, and contrasted with a more gradual evolutionary scenario. The outcome of our analysis argues against the Chomskyan view.

evolutionary biology↗