Biology subjects

Probst, V.

Publications and source records attributed to Probst, V..

4 recordsLinked to original sources

bioRxiv2026

Desmin p.R406W mutation is associated with arrhythmias through structural and electrophysiological remodeling

Background and AimsMutations in the desmin (DES) gene cause a variety of cardiomyopathies associated with arrhythmias, yet the electrophysiological consequences of these variants remain largely uncharacterized. The aim of this study was to investigate the pathogenic mechanisms of the de novo DES p.R406W variant, which was identified in a 9-year-old patient who suffered from severe ventricular arrhythmias and sudden cardiac death without overt structural heart disease. MethodsHuman induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) carrying the DES p.R406W variant (including the patients line) were compared to isogenic controls. Action potentials (AP) of hiPSC-CMs were recorded using patch-clamp. Furthermore, 3D engineered heart tissues (EHTs) were generated from hiPSC-CMs and their APs were recorded with sharp microelectrodes. Analytical techniques also included transmission electron microscopy (TEM) and integrated transcriptomic and proteomic profiling. Finally, a heterozygous knock-in (KI) mouse model carrying the Des p.R405W ortholog was evaluated through surface ECG, echocardiography and ex vivo cardiac optical mapping. ResultsThe DES p.R406W mutation prolonged AP duration in IM-R406W hiPSC-CMs and EHTs vs Control ones. Multi-omics analysis of EHTs revealed a dysregulation of genes and proteins involved in contractile function, cell adhesion, and electrical activity. TEM imaging revealed changes in Z-disc architecture in mutant tissues. Twenty-week-old Des p.R405W KI mice exhibited ventricular conduction slowing (prolonged QRS) and a high susceptibility to ventricular tachyarrhythmias, likely due to reentrant mechanisms. Mild hypertrophy was also observed, but only in females. ConclusionThe DES p.R406W variant is highly pathogenic, causing electrical and structural remodeling of the myocardium. This study highlights the effectiveness of hiPSC-CMs and EHTs in recapitulating the clinical phenotype of desminopathy, providing a platform for investigating the mechanisms of early-onset cardiac arrhythmias and SCD.

pathology↗

bioRxiv2026

MeTAL enables multiparametric risk prediction for human KCNH2 variants

BackgroundClinical interpretation of missense variants in the hERG potassium channel encoded by the KCNH2 gene remains a major challenge in inherited arrhythmia syndromes. Functional studies often rely on a minimal set of channel properties, mainly current amplitude measurements, which do not capture the multidimensional nature of channel gating and its impact on ventricular repolarization. We developed a multiscale computational framework to quantitatively link multiparametric channel dysfunction to ECG phenotypes. MethodsWe generated multiparametric electrophysiological profiles for KCNH2 variants using high-throughput patch-clamp, quantifying nine biophysical properties including conductance, voltage dependence, and gating kinetics. These parameters were incorporated into a modified formulation of IKr embedded in a human ventricular electrophysiology model. The resulting framework, termed MeTAL (Multiscale-enriched Transformation and Analysis for Long-QT), produces physiologically calibrated pseudo-ECGs enabling quantitative evaluation of QT dynamics. We systematically analyzed the contribution of individual and combined gating parameters and applied the model to 41 KCNH2 variants across ACMG classes, comparing simulated QTc values with clinical data. ResultsMultiparametric profiling revealed complex functional signatures in most variants, with concurrent gain- and loss-of-function effects affecting distinct gating processes. Simulations demonstrated that ventricular repolarization, though strongly determined by current amplitude, is substantially influenced by inactivation-related parameters, particularly the slope and voltage dependence of inactivation. Interaction analyses showed nonlinear relationships between gating parameters, explaining why variants with similar current density can produce divergent QT phenotypes. In heterozygous simulations, MeTAL reproduced clinically observed QTc distributions across variant classes and accurately predicted the repolarization regime (normal, long-QT, or short-QT) in most cases. ConclusionsMultiparametric integration of ion-channel function within a multiscale electrophysiological model enables mechanistic prediction of QT behavior beyond conductance-based metrics. This approach provides a scalable framework for interpretation of KCNH2 variants and solves the issue of risk stratification in inherited arrhythmia syndromes while offering new opportunities for variant-specific and pharmacological modeling of repolarization.

biophysics↗

bioRxiv2020

Benchmarking full-length transcript single cell mRNA sequencing protocols

Single cell mRNA sequencing technologies have transformed our understanding of cellular heterogeneity and identity. For sensitive discovery or clinical marker estimation where high transcript capture per cell is needed only plate-based techniques currently offer sufficient resolution. Here, we present a performance evaluation of three different plate-based scRNA-seq protocols. Our evaluation is aimed towards applications requiring high gene detection sensitivity, reproducibility between samples, and minimum hands-on time, as is required, for example, in clinical use. We included two commercial kits, NEBNext(R) Single Cell/ Low Input RNA Library Prep Kit (NEB(R)), SMART-seq(R) HT kit (Takara(R)), and the non-commercial protocol Genome & Transcriptome sequencing (G&T). G&T delivered the highest detection of genes per single cell, at the absolute lowest price. Takara(R) kit presented similar high gene detection per single cell, and high reproducibility between sample, but at the absolute highest price. NEB(R) delivered a lower detection of genes but remain an alternative to more expensive commercial kits.

molecular biology↗

bioRxiv2019

Genetic association analyses highlight IL6, ALPL, and NAV1 as three new susceptibility genes underlying calcific aortic valve stenosis

To date, only two replicated loci, LPA and PALMD, have been identified as causal genes for calcific aortic valve stenosis (CAVS) using genome-wide and transcriptome-wide association study (TWAS). To identify additional susceptibility genes for CAVS, we performed a GWAS meta-analysis totaling 5,115 cases and 354,072 controls of European descent. Four loci achieved genome-wide significance, including two new loci: IL6 (interleukin 6) on 7p15.3 and ALPL (alkaline phosphatase) on 1p36.12. A TWAS integrating an eQTL study of 233 human aortic valves identified NAV1 (neuron navigator 1) on 1q32.1 as a new candidate causal gene. The CAVS risk alleles were associated with higher mRNA expression of NAV1 in valve tissues. Association results at the genome-wide scale showed genetic correlation with coronary artery disease and cardiovascular risk factors. Our study highlights three new loci implicating inflammation, mineralization and blood vessel integrity in CAVS pathogenesis and supports shared genetic etiology with cardiovascular traits.

genomics↗