Biology subjects

Eschenhagen, T.

Publications and source records attributed to Eschenhagen, T..

12 recordsLinked to original sources

bioRxiv2026

Dynamic BMP10 Release Reflects Atrial Fibrillation Burden in Human Atrial Engineered Heart Tissue

Background: Atrial fibrillation (AF) burden is increasingly recognized as a determinant of clinical risk. Currently, AF burden can only be estimated using long-term rhythm monitoring. Bone morphogenetic protein 10 (BMP10) is a protein secreted from cardiac atria associated with AF and AF-related complications. This study evaluated whether BMP10 concentrations are associated with AF burden in a human atrial model: atrial engineered heart tissue (aEHT). Methods: Human induced pluripotent stem cell-derived atrial cardiomyocytes were cast into atrial engineered heart tissues (aEHTs). To mimic AF burden, mature aEHTs were optogenetically-paced at a high rate of 4 Hz, either intermittently for 4 hours every 2 days (~10% burden) or continuously for 24 hours per day (100% burden). After 18 days of high-rate pacing intervention, 7 days of recovery without pacing followed. BMP10 release was quantified by ELISA and contractile function was assessed by video analysis. EHT transcriptional remodeling in response to mimicked AF burden was assessed by RNA sequencing and the effect of recovery was analyzed by qPCR. Results: High-rate optogenetic pacing mimicking AF lead to a dynamic, burden-dependent BMP10 release: BMP10 concentrations in the medium were increased by intermittent optogenetic pacing (~10% burden) and highest under continuous optogenetic pacing (100% burden). BMP10 release declined toward control levels during recovery. Contractile dysfunction was most impaired after continuous pacing and showed only partial recovery within 7 days after pacing cessation. RNA sequencing revealed distinct burden-dependent transcriptional states. Pacing-regulated transcripts were related to BMP/TGF{beta} signaling, atrial identity, calcium handling, contractile phenotype, and electrophysiological remodeling. After recovery, BMP10 mRNA expression remained elevated despite normalization of BMP10 protein release. Conclusions: AF burden dynamically regulates BMP10 release and functional and molecular remodeling in human aEHTs. BMP10 release depicts a secreted protein-based readout of current or recent atrial high-rate stress, whereas persistent transcriptional changes indicate molecular memory of prior AF burden. These findings support BMP10 release as a burden-sensitive AF biomarker

pharmacology and toxicology↗

bioRxiv2025

Contractility governs cardiomyocyte cell cycle activity

The hearts rhythmic contractions keep blood flowing to deliver the oxygen and nutrients that sustain life, but this very strength may also explain why the heart has so little capacity to regenerate. Whereas embryonic and neonatal hearts can repair themselves, this ability is rapidly lost after birth as heart muscle cells (cardiomyocytes) exit the cell cycle. We tested whether the force-generating machinery of the heart acts as a barrier to regeneration. Across human cardiomyocytes, engineered heart tissue, and myocardial slices, we found that active force generation suppresses proliferation, whereas its inhibition, through chemogenetic or pharmacological modulation, enabled cell cycle re-entry. These findings identify contractility as a central regulator of regenerative potential, highlighting new directions for strategies to restore repair in the diseased heart.

cell biology↗

bioRxiv2024

Mitochondrial reactive oxygen species cause arrhythmias in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease and caused by genetic variants that often increase sarcomeric Ca2+ sensitivity. While Ca2+ sensitization explains diastolic dysfunction, the genesis of ventricular arrhythmias is unresolved. Here, we show that HCM mutations or pharmacological interventions that increase myofilament Ca2+ sensitivity generate bioenergetic mismatch and oxidative stress during {beta}-adrenergic stimulation which provide a trigger and a substrate for arrhythmias. For any given sarcomere shortening that produces work and consumes ATP, less Ca2+ stimulates the Krebs cycle to maintain mitochondrial NADH. This reverses the mitochondrial transhydrogenase to regenerate NADH from NADPH, supporting ATP production at the cost of NADPH-dependent antioxidative capacity. The ensuing overflow of reactive oxygen species (ROS) from mitochondria and glutathione oxidation induce spontaneous Ca2+ release from the sarcoplasmic reticulum and Ca2+ waves, well-defined triggers of arrhythmias. Furthermore, transhydrogenase-dependent ROS formation slows electrical conduction during {beta}-adrenergic stimulation in vivo, providing a substrate for arrhythmias. Chronic treatment with a mitochondrially-targeted ROS scavenger abolishes the arrhythmic burden during {beta}-adrenergic stimulation in HCM mice in vivo, while inducing mitochondrial ROS with a redox cycler is sufficient to induce arrhythmias in wild-type animals. These findings may lead to new strategies to prevent sudden cardiac death in patients with HCM.

physiology↗

bioRxiv2023

Impulse initiation in engrafted pluripotent stem cell-derived cardiomyocytes can stimulate the recipient heart.

Transplantation of pluripotent stem cell-derived cardiomyocytes is a novel promising cell-based therapeutic approach for patients with heart failure. However, engraftment arrhythmias are a predictable life-threatening complication and represent a major hurdle for clinical translation. Catheter-based electrophysiological analysis suggested that the ventricular arrhythmias were caused by an automaticity of the transplanted cells, but whether impulse generation by transplanted cardiomyocytes can propagate to the host myocardium and override the recipient rhythm has not been directly assessed experimentally. We used optogenetics to specifically activate engrafted cardiomyocytes, which resulted in impulse generation in the engrafted cardiomyocytes and stimulated the recipient heart (4/9 hearts). Thus, our study shows that transplanted cardiomyocytes can electrically couple to the host myocardium and stimulate the recipient heart, providing experimental evidence that cardiomyocyte automaticity can serve as a trigger for ventricular arrhythmias.

pharmacology and toxicology↗

bioRxiv2023

A critical role of retinoic acid concentration for the induction of a fully human-like atrial phenotype in hiPSC-CM

Retinoic acid (RA) induces an atrial phenotype in human induced pluripotent stem cells (hiPSC), but expression of atrium-selective currents such as the ultrarapid (IKur) and acetylcholine-stimulated K+ current (IK,ACh) is variable and less than in adult human atrium. We suspected methodological issues and systematically investigated the concentration-dependency of RA. RA treatment increased IKur concentration-dependently from 1.1{+/-}0.54 pA/pF (0 RA) to 3.8{+/-}1.1, 5.8{+/-}2.5 and 12.2{+/-}4.3 at 0.01, 0.1 and 1 {micro}M, respectively. Only 1 {micro}M RA induced enough IKur to fully reproduce human atrial AP shape and a robust shortening of action potentials (AP) upon carbachol. We found that sterile filtration caused substantial loss of RA. We conclude that 1 {micro}M RA appears necessary and sufficient to induce a full atrial AP shape in hiPSC-CM in EHT format. RA concentrations are prone to methodological issues and may profoundly impact success of atrial differentiation.

pharmacology and toxicology↗

bioRxiv2022

Immature human engineered heart tissues engraft in a guinea pig chronic injury model

AO_SCPLOWBSTRACTC_SCPLOWEngineered heart tissue (EHT) transplantation represents an innovative, regenerative approach for heart failure patients. Late preclinical trials are underway, and the first clinical trial has started in 2021. Preceding studies revealed functional recovery after implantation of in vitro-matured EHT in the subacute stage while transplantation in a chronic injury setting was less efficient. We hypothesized that the use of immature EHT patches (EHTIm) could improve cardiomyocytes (CM) engraftment. Chronic myocardial injury was induced in a guinea pig model (n=14). EHTIm (15x106 cells) were transplanted directly after casting. Functional consequences were assessed by serial echocardiography. Animals were sacrificed four weeks after transplantation and hearts were excised for histological analysis. Cryo-injury lead to large transmural scars amounting to 26% of the left ventricle. Grafts were identified by a positive staining for human Ku80 and dystrophin, remuscularizing 9% of the scar area on average. The CM density in the graft was higher compared to previous studies with in vitro-matured EHTs and showed a greater population of immature CM. Echocardiographic analysis showed a small improvement of left ventricular function after EHTIm transplantation. In a small translational proof-of-concept study human scale EHTIm patches (4.5x108 cells) were epicardially implanted on healthy pig hearts (n=2). In summary, we provide evidence that transplantation of immature EHT patches without pre-cultivation results in better cell engraftment.

pharmacology and toxicology↗

bioRxiv2021

Contractile force of transplanted cardiomyocytes contributes to heart function after injury

Transplantation of pluripotent stem cell-derived cardiomyocytes represents an innovative therapeutic strategy for heart failure. Studies in small and large animals have demonstrated functional recovery of left ventricular function after cardiomyocyte transplantation1-4, and first clinical studies are currently underway5. Yet, the mechanism of action underlying graft-induced benefit is unknown6. Here we demonstrate that transplanted cardiomyocytes actively contribute to heart function. We transplanted cardiomyocytes with an optogenetic off-on switch in a guinea pig cardiac injury model. Light-induced inhibition of engrafted cardiomyocyte contractility resulted in a rapid decrease of left ventricular function that was fully reversible with the offset of photostimulation. Hence, our optogenetic approach demonstrated that transplanted cardiomyocytes actively participate in heart function, supporting the hypothesis that the delivery of new force-generating myocardium can serve as a regenerative therapeutic strategy.

pharmacology and toxicology↗

bioRxiv2021

ACTN2 missense variant causes proteopathy in human iPSC-derived cardiomyocytes

Genetic variants in -actinin-2 (ACTN2) are associated with several forms of (cardio)myopathy. We previously reported a heterozygous missense (c.740C>T) ACTN2 gene variant, associated with hypertrophic cardiomyopathy, and characterized by an electro-mechanical phenotype in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Here, we created with CRISPR/Cas9 genetic tools two heterozygous functional knock-out hiPSC lines with a second wild-type (ACTN2wt) and missense ACTN2 (ACTN2mut) allele, respectively. We evaluated their impact on cardiomyocyte structure and function, using a combination of different technologies, including immunofluorescence and live cell imaging, RNA-seq, and mass spectrometry. This study showed that ACTN2mut present a higher percentage of multinucleation, protein aggregation, hypertrophy, myofibrillar disarray and activation of both the ubiquitin-proteasome system and the autophagy-lysosomal pathway as compared to ACTN2wt in 2D-cultured hiPSC-CMs. Furthermore, the expression of ACTN2mut was associated with a marked reduction of sarcomere-associated protein levels in 2D-cultured hiPSC-CMs and force impairment in engineered heart tissues. In conclusion, our study highlights the activation of proteolytic systems in ACTN2mut hiPSC-CMs likely to cope with ACTN2 aggregation and therefore directs towards proteopathy as an additional cellular pathology caused by this ACTN2 variant, which may contribute to human ACTN2-associated cardiomyopathies.

cell biology↗

bioRxiv2021

PPARdelta signaling activation improves metabolic and contractile maturation of human pluripotent stem cell-derived cardiomyocytes.

Pluripotent stem cell-derived cardiomyocytes (PSC-CMs) provide an unprecedented opportunity to study human heart development and disease. A major caveat however is that they remain functionally and structurally immature in culture, limiting their potential for disease modeling and regenerative approaches. Here, we address the question of how different metabolic pathways can be modulated in order to induce efficient hPSC-CM maturation. We show that PPAR signaling acts in an isoform-specific manner to balance glycolysis and fatty acid oxidation (FAO). PPARD activation or inhibition results in efficient respective up- or down-regulation of the gene regulatory networks underlying FAO in hPSC-CMs. PPARD induction further increases mitochondrial and peroxisome content, enhances mitochondrial cristae formation and augments FAO flux. Lastly PPARD activation results in enhanced myofibril organization and improved contractility. Transient lactate exposure, commonly used in hPSC-CM purification protocols, induces an independent program of cardiac maturation, but when combined with PPARD activation equally results in a metabolic switch to FAO. In summary, we identify multiple axes of metabolic modifications of hPSC-CMs and a role for PPARD signaling in inducing the metabolic switch to FAO in hPSC-CMs. Our findings provide new and easily implemented opportunities to generate mature hPSC-CMs for disease modeling and regenerative therapy.

cell biology↗

bioRxiv2021

Human engineered heart tissue transplantation in a guinea pig chronic injury model

AO_SCPLOWBSTRACTC_SCPLOWMyocardial injury leads to an irreversible loss of cardiomyocytes (CM). The implantation of human engineered heart tissue (EHT) has become a promising regenerative approach. Previous studies exhibited beneficial, dose-dependent effects of human induced pluripotent stem cell (hiPSC)-derived EHT patch transplantation in a guinea pig model in the subacute phase of myocardial injury. Yet, advanced heart failure often results from a chronic remodeling process. Therefore, from a clinical standpoint it is worthwhile to explore the ability to repair the chronically injured heart. In this study human EHT patches were generated from hiPSC-derived CMs (15x106 cells) and implanted epicardially four weeks after injury in a guinea-pig cryo-injury model. Cardiac function was evaluated by echocardiography after a follow-up period of four weeks. Hearts revealed large transmural myocardial injuries amounting to 27% of the left ventricle. EHT recipient hearts demonstrated compact muscle islands of human origin in the scar region, as indicated by a positive staining for human Ku80 and dystrophin, remuscularizing 5% of the scar area. Echocardiographic analysis demonstrated no significant difference between animals that received EHT patches and animals in the control group (fractional area change 36% vs. 34%). Thus, EHT patches engrafted in the chronically injured heart but in contrast to the subacute model, grafts were smaller and EHT patch transplantation did not improve left ventricular function, highlighting the difficulties for a regenerative approach.

pharmacology and toxicology↗

bioRxiv2020

SARS-CoV-2 infects and induces cytotoxic effects in human cardiomyocytes

BackgroundThe coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has emerged as global pandemic. SARS-CoV-2 infection can lead to elevated markers of cardiac injury associated with higher risk of mortality in COVID-19 patients. It is unclear whether cardiac injury may have been caused by direct infection of cardiomyocytes or is mainly secondary to lung injury and inflammation. Here we investigate whether human cardiomyocytes are permissive for SARS-CoV-2 infection. MethodsInfection was induced by two strains of SARS-CoV-2 (FFM1 and FFM2) in human induced pluripotent stem cells-derived cardiomyocytes (hiPS-CM) and in two models of human cardiac tissue. ResultsWe show that SARS-CoV-2 infects hiPS-CM as demonstrated by detection of intracellular double strand viral RNA and viral spike glycoprotein protein expression. Increasing concentrations of virus RNA are detected in supernatants of infected cardiomyocytes, which induced infections in CaCo-2 cell lines documenting productive infections. SARS-COV-2 infection induced cytotoxic and pro-apoptotic effects and abolished cardiomyocyte beating. RNA sequencing confirmed a transcriptional response to viral infection as demonstrated by the up-regulation of genes associated with pathways related to viral response and interferon signaling, apoptosis and reactive oxygen stress. SARS-CoV-2 infection and cardiotoxicity was confirmed in a iPS-derived human 3D cardiosphere tissue models. Importantly, viral spike protein and viral particles were detected in living human heart slices after infection with SARS-CoV-2. ConclusionsThe demonstration that cardiomyocytes are permissive for SARS-CoV-2 infection in vitro warrants the further in depth monitoring of cardiotoxic effects in COVID-19 patients. Clinical PerspectiveO_ST_ABSWhat is New?C_ST_ABSO_LIThis study demonstrates that human cardiac myocytes are permissive for SARS-CoV-2 infection. C_LIO_LIThe study documents that SARS-CoV-2 undergoes a full replicatory circle and induces a cytotoxic response in cardiomyocytes. C_LIO_LIInfection was confirmed in two cardiac tissue models, including living human heart slices. C_LI What are the Clinical Implications?O_LIThe study may provide a rational to explain part of the cardiotoxicity observed in COVID-19 patients C_LIO_LIThe demonstration of direct cardiotoxicity induced by SARS-CoV-2 warrants an in depth further analysis of cardiac tissue of COVID-19 patients and a close monitoring for putative direct cardiomyocyte injury. C_LIO_LIThe established models can be used to test novel therapeutic approaches targeting COVID-19. C_LI

cell biology↗

bioRxiv2017

Versatile open software to quantify cardiomyocyte and cardiac muscle contraction in vitro and in vivo

Contraction of muscle reflects its physiological state. Methods to quantify contraction are often complex, expensive and tailored to specific models or recording conditions, or require specialist knowledge for data extraction. Here we describe an automated, open-source software tool (MUSCLEMOTION) adaptable for use with standard laboratory and clinical imaging equipment that enables quantitative analysis of normal cardiac contraction, disease phenotypes and pharmacological responses. MUSCLEMOTION allowed rapid and easy measurement of contractility in (i) single cardiomyocytes from primary adult heart and human pluripotent stem cells, (ii) multicellular 2D-cardiomyocyte cultures, 3D engineered heart tissues and cardiac organoids/microtissues in vitro and (iii) intact hearts of zebrafish and humans in vivo. Good correlation was found with conventional measures of contraction in each system. Thus, using a single method for processing video recordings, we obtained reliable pharmacological data and measures of cardiac disease phenotype in experimental cell- and animal models and human echocardiograms.

physiology↗