Generation of an isogenic series of genome-edited hiPSC lines with the BAG3-mutation for modeling myofibrillar myopathy 6.

BAG3 contributes to the maintenance of proteostasis through chaperone-assisted selective autophagy. This function is impaired by a single amino acid exchange (P209L) in the protein, which causes myofibrillar myopathy-6 (MFM6). This disease manifests as severe skeletal muscle weakness, neuropathy and restrictive cardiomyopathy.

Generation of two isogenic control lines by correcting the BAG3 P209L mutation of human induced pluripotent stem cell (hiPSC) lines from patients with myofibrillar myopathy-6.

BAG3 plays a key role in proteostasis as a central component of the chaperone-assisted selective autophagy (CASA) complex. A point mutation (p.P209L; c.

Generation and characterization of an isogenic control line by correcting the BAG3 P209L mutation of a human induced pluripotent stem cell (hiPSC) line from a patient with myofibrillar myopathy-6.

BAG3 is a central component of the chaperone-assisted selective autophagy complex and thus important for proteostasis. This function is affected by a point mutation (p.P209L; c.

RNA-Binding Protein Hnrnpa1 Triggers Daughter Cardiomyocyte Formation by Promoting Cardiomyocyte Dedifferentiation and Cell Cycle Activity in a Post-Transcriptional Manner.

Stimulating cardiomyocyte (CM) dedifferentiation and cell cycle activity (DACCA) is essential for triggering daughter CM formation. In addition to transcriptional processes, RNA-binding proteins (RBPs) are emerging as crucial post-transcriptional players in regulating CM DACCA. However, whether post-transcriptional regulation of CM DACCA by RBPs could effectively trigger daughter CM formation remains unknown.

Forward programming of human induced pluripotent stem cells via the ETS variant transcription factor 2: rapid, reproducible, and cost-effective generation of highly enriched, functional endothelial cells.

Aims: Endothelial cell (EC) dysfunction plays a key role in the initiation and progression of cardiovascular disease. However, studying these disorders in ECs from patients is challenging; hence, the use of human induced pluripotent stem cells (hiPSCs) and their in vitro differentiation into ECs represents a very promising approach. Still, the generation of hiPSC-derived ECs (hECs) remains demanding as a cocktail of growth factors and an intermediate purification step are required for hEC enrichment.

Right ventricular cardiomyocyte expansion accompanies cardiac regeneration in newborn mice after large left ventricular infarcts.

Cauterization of the root of the left coronary artery (LCA) in the neonatal heart on postnatal day 1 (P1) resulted in large, reproducible lesions of the left ventricle (LV), and an attendant marked adaptive response in the right ventricle (RV). The response of both chambers to LV myocardial infarction involved enhanced cardiomyocyte (CM) division and binucleation, as well as LV revascularization, leading to restored heart function within 7 days post surgery (7 dps). By contrast, infarction of P3 mice resulted in cardiac scarring without a significant regenerative and adaptive response of the LV and the RV, leading to subsequent heart failure and death within 7 dps.

Combined use of magnetic microbeads for endothelial cell isolation and enhanced cell engraftment in myocardial repair.

The regenerative potential of the heart after injury is limited. Therefore, cell replacement strategies have been developed. However, the engraftment of transplanted cells in the myocardium is very inefficient.

LDHA-mediated metabolic reprogramming promoted cardiomyocyte proliferation by alleviating ROS and inducing M2 macrophage polarization.

Aims: Metabolic switching during heart development contributes to postnatal cardiomyocyte (CM) cell cycle exit and loss of regenerative capacity in the mammalian heart. Metabolic control has potential for developing effective CM proliferation strategies. We sought to determine whether lactate dehydrogenase A (LDHA) regulated CM proliferation by inducing metabolic reprogramming.

High-Throughput Screening Platform in Postnatal Heart Cells and Chemical Probe Toolbox to Assess Cardiomyocyte Proliferation.

Restoring lost heart muscle is an attractive goal for cardiovascular regenerative medicine. One appealing strategy is the therapeutic stimulation of cardiomyocyte proliferation, which remains challenging due to available assay technologies capturing the complex biology. Here, a high-throughput-formatted phenotypic assay platform was established using rodent whole heart-derived cells to preserve the cellular environment of cardiomyocytes.

Bone marrow CD73 mesenchymal stem cells display increased stemness and promote fracture healing .

Mesenchymal stem cells (MSCs) are multipotent and considered to be of great potential for regenerative medicine. We could show recently (Breitbach, Kimura et al. 2018) that a subpopulation of MSCs as well as sinusoidal endothelial cells (sECs) in the bone marrow (BM) of CD73-EGFP reporter mice could be labeled .

Maintaining proteostasis under mechanical stress.

Cell survival, tissue integrity and organismal health depend on the ability to maintain functional protein networks even under conditions that threaten protein integrity. Protection against such stress conditions involves the adaptation of folding and degradation machineries, which help to preserve the protein network by facilitating the refolding or disposal of damaged proteins. In multicellular organisms, cells are permanently exposed to stress resulting from mechanical forces.

Overexpression of human BAG3 in mice causes restrictive cardiomyopathy.

An amino acid exchange (P209L) in the HSPB8 binding site of the human co-chaperone BAG3 gives rise to severe childhood cardiomyopathy. To phenocopy the disease in mice and gain insight into its mechanisms, we generated humanized transgenic mouse models. Expression of human BAG3-eGFP in mice caused Z-disc disintegration and formation of protein aggregates.

Proximity to injury, but neither number of nuclei nor ploidy define pathological adaptation and plasticity in cardiomyocytes.

The adult mammalian heart consists of mononuclear and binuclear cardiomyocytes (CMs) with various ploidies. However, it remains unclear whether a variation in ploidy or number of nuclei is associated with distinct functions and injury responses in CMs, including regeneration. Therefore, we investigated transcriptomes and cellular as well as nuclear features of mononucleated and binucleated CMs in adult mouse hearts with and without injury.

Wnt Activation and Reduced Cell-Cell Contact Synergistically Induce Massive Expansion of Functional Human iPSC-Derived Cardiomyocytes.

Modulating signaling pathways including Wnt and Hippo can induce cardiomyocyte proliferation in vivo. Applying these signaling modulators to human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in vitro can expand CMs modestly (<5-fold). Here, we demonstrate massive expansion of hiPSC-CMs in vitro (i.

Role of Mononuclear Cardiomyocytes in Cardiac Turnover and Regeneration.

Purpose Of Review: The typical remodeling process after cardiac injury is scarring and compensatory hypertrophy. The limited regeneration potential of the adult heart is thought to be due to the post-mitotic status of postnatal cardiomyocytes, which are mostly binucleated and/or polyploid. Nevertheless, there is evidence for cardiomyocyte turnover in the adult heart.

In vivo detection of programmed cell death during mouse heart development.

Despite the great progress on the cell biology of programmed cell death (PCD), its incidence and exact time course during embryonic and particular heart development are still unclear. This is also due to the lack of models enabling to directly identify and monitor PCD cells at different time points in vivo. Herein we report generation of transgenic murine embryonic stem cell and mouse models expressing secreted Annexin V-YFP under control of the CAG promoter.

Structure of the Current Sheet in the 11 July 2017 Electron Diffusion Region Event.

The structure of the current sheet along the Magnetospheric Multiscale (MMS) orbit is examined during the 11 July 2017 Electron Diffusion Region (EDR) event. The location of MMS relative to the X-line is deduced and used to obtain the spatial changes in the electron parameters. The electron velocity gradient values are used to estimate the reconnection electric field sustained by nongyrotropic pressure.

Optogenetic stimulation of G-signaling in the heart with high spatio-temporal precision.

The standard technique for investigating adrenergic effects on heart function is perfusion with pharmaceutical agonists, which does not provide high temporal or spatial precision. Herein we demonstrate that the light sensitive G-protein coupled receptor JellyOp enables optogenetic stimulation of G-signaling in cardiomyocytes and the whole heart. Illumination of transgenic embryonic stem cell-derived cardiomyocytes or of the right atrium of mice expressing JellyOp elevates cAMP levels and instantaneously accelerates spontaneous beating rates similar to pharmacological β-adrenergic stimulation.

PECAM/eGFP transgenic mice for monitoring of angiogenesis in health and disease.

For the monitoring of vascular growth as well as adaptive or therapeutic (re)vascularization endothelial-specific reporter mouse models are valuable tools. However, currently available mouse models have limitations, because not all endothelial cells express the reporter in all developmental stages. We have generated PECAM/eGFP embryonic stem (ES) cell and mouse lines where the reporter gene labels PECAM endothelial cells and vessels with high specificity.

Midbody Positioning and Distance Between Daughter Nuclei Enable Unequivocal Identification of Cardiomyocyte Cell Division in Mice.

Rationale: New strategies in the field of cardiac regeneration are directed at identifying proliferation-inducing substances to induce regrowth of myocardium. Current screening assays utilize neonatal cardiomyocytes and markers for cytokinesis, such as Aurora B-kinase. However, detection of cardiomyocyte division is complicated because of cell cycle variants, in particular, binucleation.

The Transcription Factor ETV1 Induces Atrial Remodeling and Arrhythmia.

Rationale: Structural and electrophysiological remodeling of the atria are recognized consequences of sustained atrial arrhythmias, such as atrial fibrillation. The identification of underlying key molecules and signaling pathways has been challenging because of the changing cell type composition during structural remodeling of the atria.

Objective: Thus, the aims of our study were (1) to search for transcription factors and downstream target genes, which are involved in atrial structural remodeling, (2) to characterize the significance of the transcription factor ETV1 (E twenty-six variant 1) in atrial remodeling and arrhythmia, and (3) to identify ETV1-dependent gene regulatory networks in atrial cardiac myocytes.

In Vivo Labeling by CD73 Marks Multipotent Stromal Cells and Highlights Endothelial Heterogeneity in the Bone Marrow Niche.

Despite much work studying ex vivo multipotent stromal cells (MSCs), the identity and characteristics of MSCs in vivo are not well defined. Here, we generated a CD73-EGFP reporter mouse to address these questions and found EGFP MSCs in various organs. In vivo, EGFP mesenchymal cells were observed in fetal and adult bones at proliferative ossification sites, while in solid organs EGFP cells exhibited a perivascular distribution pattern.

Visualization of endothelial cell cycle dynamics in mouse using the Flt-1/eGFP-anillin system.

Endothelial cell proliferation is a key process during vascular growth but its kinetics could only be assessed in vitro or ex vivo so far. To enable the monitoring and quantification of cell cycle kinetics in vivo, we have generated transgenic mice expressing an eGFP-anillin construct under control of the endothelial-specific Flt-1 promoter. This construct labels the nuclei of endothelial cells in late G1, S and G2 phase and changes its localization during the different stages of M phase, thereby enabling the monitoring of EC proliferation and cytokinesis.