Biology subjects

van der Velden, J.

Publications and source records attributed to van der Velden, J..

7 recordsLinked to original sources

bioRxiv2026

Phosphoproteomics of Hypertrophic Cardiomyopathy Patient Myocardium and Novel hiPSC-CM Model Reveal Protein Kinase A as a Modulator of Microtubule Repolymerization

Background and aimsIncreased levels of -tubulin and its post-translational modifications (PTMs) are found in human heart failure and could initiate diastolic dysfunction by modulating cardiomyocyte stiffness. How these modifications occur and how they may underlie cardiac dysfunction remains unknown. Upstream kinases may play a critical role, but this has not been explored. Methods and resultsHere we address this question by, for the first time ever, determining levels of the enzymes involved in microtubule (MT) detyrosination and acetylation (TAT1, HDAC6) in a well-characterized cohort of patients with hypertrophic cardiomyopathy (HCM). In HCM patients (N=10-11), protein levels of detyrosination enzymes remain unaltered, whilst levels of TAT1 and HDAC6 were decreased and increased, respectively. Phosphoproteomics in HCM (N=24) and control (N=8) myocardium identified significant differences in over 1900 serine/threonine and 160 tyrosine phosphosites, in addition to increased EGFR/IGF1R-MAPK signaling in HCM. We subsequently showed that MT repolymerization was increased in HCM MYBPC3Arg943X hiPSC-CMs. Isoprenaline-mediated PKA activation decreased MT repolymerization in hiPSC-CMs and revealed CLASP1, MAST4 and MAP1A as potential MT modifiers in HCM. ConclusionsWe show that the altered HCM MT code cannot be attributed to levels of key MT-modifying enzymes. By combining kinome analyses in human HCM hearts with hiPSC-CM studies on MT dynamics, PTMs and contractility we unveiled a regulatory role for MTs in the cardiomyocyte response to beta-adrenergic receptor stimulation. Disease-mediated changes in the MT code thereby exert both a direct, and indirect effect on cardiac function via mediating the response to adrenergic activation. Graphical Abstract created with BioRender.com O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=122 SRC="FIGDIR/small/706710v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@1c58dc4org.highwire.dtl.DTLVardef@de502eorg.highwire.dtl.DTLVardef@1621512org.highwire.dtl.DTLVardef@557b82_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2025

Integrated Multi-Omics Mapping of Mitochondrial Dysfunction and Substrate Preference in Barth Syndrome Cardiac Tissue

Barth syndrome (BTHS) is a rare X-linked recessively inherited disorder caused by variants in the TAFAZZIN gene, leading to impaired conversion of monolysocardiolipin (MLCL) into mature cardiolipin (CL). Accumulation of MLCL and CL deficiency are diagnostic markers for BTHS. Clinically, BTHS includes cardiomyopathy, skeletal myopathy, neutropenia, and growth delays. Severely affected patients may require early cardiac transplants due to unpredictable cardiac phenotypes. The pathophysiological mechanisms of BTHS are poorly understood, and treatments remain symptomatic. This study analyzed heart samples from five pediatric male BTHS patients (5 months-15 years) and compared them to tissues from 24 non-failing donors (19-71 years) using an integrated omics method combining metabolomics, lipidomics, and proteomics. The analysis confirmed changes in diagnostic markers (CL and MLCL), severe mitochondrial alterations, metabolic shifts, and elevated heart-failure markers. It also revealed significant interindividual differences among BTHS patients. With this study describe a powerful analytical tool for the in-depth analysis of metabolic disorders and a solid foundation for the understanding of BTHS disease phenotypes in cardiac tissues.

molecular biology↗

bioRxiv2025

Microtubule detyrosination alters nuclear mechanotransduction and leads to pro-hypertrophic signaling in hypertrophic cardiomyopathy

BackgroundHypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy and diastolic dysfunction and is accompanied by extensive cytoskeletal remodeling, including increased protein levels of desmin, tubulin and detyrosinated tubulin. We have previously demonstrated that tubulin detyrosination contributes to diastolic dysfunction. Microtubules are connected to the nucleus by the LINC complex, yet the role of cytoskeleton-nucleus interactions in HCM remain poorly understood. ObjectivesWe investigated whether cytoskeletal remodeling in HCM alters nuclear morphology and mechanics, and modulates hypertrophy-associated signaling pathways. MethodsNuclear morphology was assessed by electron microscopy and immunofluorescence in cardiac septal tissue from obstructive HCM patients (N=19) and non-failing donors (NF, N=8), as well as in Wild-Type (WT, N=18) and homozygous HCM-associated Mybpc3 c.2373InsG mice (Mybpc3c.2373InsG, N=19). A novel live-cell imaging approach was used to study nuclear deformation during cardiomyocyte contraction. YAP1 nuclear translocation was measured to evaluate downstream mechanosensitive signaling and detyrosination inhibitor epoY was used to test causality. ResultsNuclei were highly invaginated and enlarged in HCM in both patients and mice. Nuclear deformation during contraction was restricted in HCM cardiomyocytes, indicating altered mechanotransduction. These changes were associated with increased YAP1 nuclear localization and induction of YAP1 target and hypertrophic genes. Inhibition of microtubule detyrosination reduced nuclear invaginations, restored nuclear deformation and decreased YAP1 nuclear translocation. ConclusionCytoskeletal remodeling in HCM is associated with altered nuclear morphology and mechanotransduction, accompanied by YAP1 translocation which may contribute to hypertrophic remodeling. Targeting microtubule detyrosination rescues this phenotype, identifying nuclear mechanotransduction as a potential therapeutic target for HCM. Unstructured abstractHypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy and diastolic dysfunction and is accompanied by extensive cytoskeletal remodeling, including increased desmin, tubulin, and detyrosinated tubulin levels, which we previously showed contribute to impaired relaxation. Since microtubules connect to the nucleus via the LINC complex, we investigated whether cytoskeletal remodeling alters nuclear morphology, mechanics, and hypertrophy-associated signaling. Using electron microscopy and immunofluorescence in cardiac septal tissue from obstructive HCM patients and non-failing donors, and immunofluorescence and live-cell imaging in septal tissue from Wild-Type and homozygous HCM-associated Mybpc3 c.2373InsG mice, we found that nuclei were enlarged and highly invaginated, with restricted nuclear deformation during contraction, indicating altered mechanotransduction. These changes were associated with increased YAP1 nuclear localization and increased expression of YAP1 target and hypertrophic genes. Inhibiting microtubule detyrosination reduced nuclear abnormalities, restored nuclear deformation, and decreased YAP1 nuclear translocation, identifying nuclear mechanotransduction as a potential therapeutic target in HCM. Visual abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=122 SRC="FIGDIR/small/646061v2_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@7f915forg.highwire.dtl.DTLVardef@12131c6org.highwire.dtl.DTLVardef@4aff5eorg.highwire.dtl.DTLVardef@1c3a3a8_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LICytoskeletal remodeling contributes to nuclear abnormalities and impaired mechanotransduction in hypertrophic cardiomyopathy. C_LIO_LIMicrotubule detyrosination promotes nuclear invaginations and increased YAP1 signaling in hypertrophic cardiomyopathy. C_LIO_LIPharmacological reduction of detyrosinated tubulin normalizes nuclear structure and mechanosignaling. C_LIO_LITargeting nuclear-cytoskeletal coupling may provide new therapeutic strategies for hypertrophic cardiomyopathy. C_LI

physiology↗

bioRxiv2024

NUAK1 regulates contraction in vascular smooth muscle cells derived from abdominal aortic aneurysm patients

AimAbdominal aortic aneurysms (AAA) are defined as a dilatation of the aortic wall. Impaired contractile ability of vascular smooth muscle cells (vSMC) is a hallmark of AAA. This study investigates the underlying mechanism of altered in vitro contractility of vSMC derived from AAA patients (AAA-SMC) compared to control vSMC (C-SMC). MethodsContractility of AAA-SMC (n=24) and C-SMC (n=8) was measured using Electric Cell- substrate Impedance Sensing. Large variability in AAA-SMC contraction was observed compared to C-SMC contraction, and AAA-SMC were therefore subdivided into low, intermediate (i.e. comparable to C-SMC contraction) and high contracting. To identify novel proteins involved in altered AAA-SMC contraction, a phosphoproteomic analysis was performed. ResultsThe proteomics data showed that Thrombospondin-1, PDZ and LIM domain protein 4 and ATPase plasma membrane Ca2+ transporting 1 expression correlated with vSMC contraction, but knockdown (KD) of these targets did not affect contraction. Next, the phosphoproteomics data identified NUAK family kinase 1 (NUAK1) as a potential regulator of contraction, since its kinase activity correlated with AAA-SMC contraction. NUAK1 regulates Myosin phosphatase targeting subunit 1 (MYPT1) activity by phosphorylation, as confirmed by the correlation between NUAK1 activity and phosphorylation levels of Ser445 and Ser910 on MYPT1. NUAK1 protein and RNA expression correlated with AAA-SMC contraction. Moreover, NUAK1 KD decreased contraction in AAA-SMC, combined with reduced phosphorylation levels of Myosin light chain (pMLC) and Vinculin gene expression, and increased F-actin cytoskeletal filament levels. ConclusionsNUAK1 regulates AAA-SMC contraction. Low NUAK1 expression decreased pMLC, potentially by higher MYPT1 activity, and subsequently reduced contraction. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=101 SRC="FIGDIR/small/629332v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@41c0f0org.highwire.dtl.DTLVardef@e1dd1borg.highwire.dtl.DTLVardef@7b36d7org.highwire.dtl.DTLVardef@14d65b5_HPS_FORMAT_FIGEXP M_FIG C_FIG Elements were modified from Servier Medical Art, licensed under a Creative Common Attribution 3.0 Generic License. https://smart.servier.com/; https://creativecommons.org/licenses/by/3.0/ HighlightsO_LIQuantification of in vitro vascular smooth muscle cells (vSMC) contractile capacity revealed large variation in contraction of vSMC derived from human AAA tissue (AAA- SMC) compared to vSMC derived from healthy aortic biopsies (C-SMC). C_LIO_LIPhosphoproteomic analysis identified NUAK family kinase 1 (NUAK1) as a novel regulator of contraction in AAA-SMC, since its kinase activity and expression levels correlated with AAA-SMC contraction. C_LIO_LINUAK1 regulates contraction in AAA-SMC by regulating Myosin phosphatase targeting subunit 1 (MYPT1) activity through phosphorylation, which subsequently affects phosphorylation levels of Myosin light chain (pMLC), and by affecting Vinculin expression and F-actin cytoskeletal filament levels. C_LIO_LIGaining more insight into NUAK1 function and mechanisms leading to aortic wall weakening can ultimately contribute to better AAA disease prediction and treatment. C_LI

cell biology↗

bioRxiv2023

Reducing microtubule detyrosination improves heart function in HCM mice and human iPSC-engineered heart tissues

RationaleHypertrophic cardiomyopathy (HCM) is the most common cardiac genetic disorder caused by sarcomeric gene variants and associated with left ventricular (LV) hypertrophy and diastolic dysfunction. The role of the microtubule network has recently gained interest with the findings that -tubulin detyrosination (dTyr-tub) is markedly elevated in heart failure. Acute reduction of dTyr-tub by inhibition of the detyrosinase (VASH/SVBP complex) or activation of the tyrosinase (tubulin tyrosine ligase, TTL) markedly improved contractility and reduced stiffness in human failing cardiomyocytes, and thus poses a new perspective for HCM treatment. ObjectiveIn this study, we tested the impact of chronic tubulin tyrosination in a HCM mouse model (Mybpc3-knock-in; KI), in human HCM cardiomyocytes and in SVBP-deficient human engineered heart tissues (EHTs). Methods and ResultsAAV9-mediated TTL transfer was applied in neonatal wild-type (WT) rodents and 3-week-old KI mice and in HCM human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes. We show that i) TTL for 6 weeks dose-dependently reduced dTyr-tub and improved contractility without affecting cytosolic calcium transients in WT cardiomyocytes; ii) TTL for 12 weeks improved diastolic filling, cardiac output and stroke volume and reduced stiffness in KI mice; iii) TTL for 10 days normalized cell hypertrophy in HCM hiPSC-cardiomyocytes; iv) TTL induced a marked transcription and translation of several tubulins and modulated mRNA or protein levels of components of mitochondria, Z-disc, ribosome, intercalated disc, lysosome and cytoskeleton in KI mice; v) SVBP-deficient EHTs exhibited reduced dTyr-tub levels, higher force and faster relaxation than TTL-deficient and WT EHTs. RNA-seq and mass spectrometry analysis revealed distinct enrichment of cardiomyocyte components and pathways in SVBP-KO vs. TTL-KO EHTs. ConclusionThis study provides the first proof-of-concept that chronic activation of tubulin tyrosination in HCM mice and in human EHTs improves heart function and holds promise for targeting the non-sarcomeric cytoskeleton in heart disease.

physiology↗

bioRxiv2022

Cardiac myosin binding protein-C palmitoylation is associated with increased myofilament affinity, reduced myofilament Ca2+ sensitivity and is increased in ischaemic heart failure.

Cardiac myosin binding protein-C (cMyBP-C) is an essential regulator of cardiac contractility through its interactions with the thick and thin filament. cMyBP-C is heavily influenced by post-translational modifications, including phosphorylation which improves cardiac inotropy and lusitropy, and S-glutathionylation, which impairs phosphorylation and is increased in heart failure. Palmitoylation is an essential cysteine modification that regulates the activity of cardiac ion channels and soluble proteins, however, its relevance to myofilament proteins has not been investigated. In the present study, we purified palmitoylated proteins from ventricular cardiomyocytes and identified that cardiac actin, myosin and cMyBP-C are palmitoylated. The palmitoylated form of cMyBP-C was more resistant to salt extraction from the myofilament lattice than the non-palmitoylated form. Isometric tension measurements suggest c-MyBP-C palmitoylation reduces myofilament Ca2+ sensitivity, with no change to maximum force or passive tension. Importantly, cMyBP-C palmitoylation levels are reduced at the site of injury in a rabbit model of heart failure but increased in samples from patients with ischaemic heart failure. Identification of cMyBP-C palmitoylation site revealed S-glutathionylated cysteines C635 and C651 are required for cMyBP-C palmitoylation, suggesting an interplay between the modifications at these sites. We conclude that structural and contractile proteins within the myofilament lattice are palmitoylated, with important functional consequences for cardiac contractile performance.

cell biology↗

bioRxiv2018

Extracellular SPARC improves cardiomyocyte contraction during health and disease

Secreted protein acidic and rich in cysteine (SPARC) is a non-structural extracellular matrix protein that regulates interactions between the matrix and neighboring cells. In the cardiovascular system, it is expressed by cardiac fibroblasts, endothelial cells, and in lower levels by ventricular cardiomyocytes. SPARC expression levels are increased upon myocardial injury and also during hypertrophy and fibrosis. We have previously shown that SPARC improves cardiac function after myocardial infarction by regulating post-synthetic procollagen processing, however whether SPARC directly affects cardiomyocyte contraction is still unknown. In this study we demonstrate a novel inotropic function for extracellular SPARC in the healthy heart as well as in the diseased state after myocarditis-induced cardiac dysfunction. We demonstrate SPARC presence on the cardiomyocyte membrane where it is co-localized with the integrin-beta1 and the integrin-linked kinase. Moreover, extracellular SPARC directly improves cardiomyocyte cell shortening ex vivo and cardiac function in vivo, both in healthy myocardium and during coxsackie virus-induced cardiac dysfunction. In conclusion, we demonstrate a novel inotropic function for SPARC in the heart, with a potential therapeutic application when myocyte contractile function is diminished such as that caused by a myocarditis-related cardiac injury.

physiology↗