Epicardioid single-cell genomics uncovers principles of human epicardium biology in heart development and disease.

The epicardium, the mesothelial envelope of the vertebrate heart, is the source of multiple cardiac cell lineages during embryonic development and provides signals that are essential to myocardial growth and repair. Here we generate self-organizing human pluripotent stem cell-derived epicardioids that display retinoic acid-dependent morphological, molecular and functional patterning of the epicardium and myocardium typical of the left ventricular wall. By combining lineage tracing, single-cell transcriptomics and chromatin accessibility profiling, we describe the specification and differentiation process of different cell lineages in epicardioids and draw comparisons to human fetal development at the transcriptional and morphological levels.

Retinoic acid signaling modulation guides in vitro specification of human heart field-specific progenitor pools.

Cardiogenesis relies on the precise spatiotemporal coordination of multiple progenitor populations. Understanding the specification and differentiation of these distinct progenitor pools during human embryonic development is crucial for advancing our knowledge of congenital cardiac malformations and designing new regenerative therapies. By combining genetic labelling, single-cell transcriptomics, and ex vivo human-mouse embryonic chimeras we uncovered that modulation of retinoic acid signaling instructs human pluripotent stem cells to form heart field-specific progenitors with distinct fate potentials.

Ongoing toxin-positive diphtheria outbreaks in a federal asylum centre in Switzerland, analysis July to September 2022.

Two diphtheria outbreaks occurred in a Swiss asylum center from July to October 2022, one is still ongoing. Outbreaks mainly involved minors and included six symptomatic respiratory diphtheria cases requiring antitoxin. Phylogenomic analyses showed evidence of imported and local transmissions of toxigenic strains in respiratory and skin lesion samples.

High-throughput optical action potential recordings in hiPSC-derived cardiomyocytes with a genetically encoded voltage indicator in the locus.

Cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSCs) represent an excellent model in cardiovascular research. Changes in their action potential (AP) dynamics convey information that is essential for disease modeling, drug screening and toxicity evaluation. High-throughput optical AP recordings utilizing intramolecular Förster resonance energy transfer (FRET) of the voltage-sensitive fluorescent protein (VSFP) have emerged as a substitute or complement to the resource-intensive patch clamp technique.

Organoids as tools for fundamental discovery and translation-a Keystone Symposia report.

Complex three-dimensional in vitro organ-like models, or organoids, offer a unique biological tool with distinct advantages over two-dimensional cell culture systems, which can be too simplistic, and animal models, which can be too complex and may fail to recapitulate human physiology and pathology. Significant progress has been made in driving stem cells to differentiate into different organoid types, though several challenges remain. For example, many organoid models suffer from high heterogeneity, and it can be difficult to fully incorporate the complexity of in vivo tissue and organ development to faithfully reproduce human biology.

Granulocyte Colony-Stimulating Factor Mediated Regulation of Early Myeloid Cells in Zebrafish.

Background: Colony-stimulating factor 3 (CSF3), more commonly known as granulocyte colony-stimulating factor (G-CSF), acts via a specific cell surface receptor CSF3R (or G-CSFR) to regulate hematopoiesis, with a particularly key role in the myeloid cell lineage where it impacts the development and function of neutrophilic granulocytes. Zebrafish possess a conserved CSF3R homologue, Csf3r, which is involved in both steady-state and emergency myelopoiesis, as well as regulating early myeloid cell migration. Two CSF3 proteins have been identified in zebrafish, Csf3a and Csf3b.

Generation of heterozygous (MRli003-A-5) and homozygous (MRli003-A-6) voltage-sensing knock-in human iPSC lines by CRISPR/Cas9 editing of the AAVS1 locus.

Assessment of the electrophysiological properties of cardiomyocytes is necessary for phenotyping cardiac disorders and for drug screening. Optical action potential imaging using a genetically encoded voltage-sensing fluorescent protein (VSFP) allows for high-throughput functional characterization of cardiomyocytes, which offers an advantage over the traditional patch-clamp technique. Here, we knocked VSFP into the AAVS1 safe harbor locus of human iPSCs, generating two stable voltage indicator lines - one heterozygous (MRIi003-A-5) and the other homozygous (MRI003-A-6).

Generation of heterozygous (MRli003-A-3) and homozygous (MRli003-A-4) TRPM4 knockout human iPSC lines.

TRPM4 is a Ca-activated channel mediating the transport of monovalent cations across the cell membrane. Mutations in the TRPM4 gene have been associated with cardiac arrhythmias in humans. Using CRISPR/Cas9 gene editing technology, we established two TRPM4 knockout human iPSC lines - one heterozygous (MRli003-A-3) and one homozygous (MRli003-A-4) - by inserting a frameshift mutation in exon 2 of the TRPM4 gene.

Cell cycle defects underlie childhood-onset cardiomyopathy associated with Noonan syndrome.

Childhood-onset myocardial hypertrophy and cardiomyopathic changes are associated with significant morbidity and mortality in early life, particularly in patients with Noonan syndrome, a multisystemic genetic disorder caused by autosomal dominant mutations in genes of the Ras-MAPK pathway. Although the cardiomyopathy associated with Noonan syndrome (NS-CM) shares certain cardiac features with the hypertrophic cardiomyopathy caused by mutations in sarcomeric proteins (HCM), such as pathological myocardial remodeling, ventricular dysfunction, and increased risk for malignant arrhythmias, the clinical course of NS-CM significantly differs from HCM. This suggests a distinct pathophysiology that remains to be elucidated.

Generation of heterozygous (MRli003-A-1) and homozygous (MRli003-A-2) MYH10 knockout human iPSC lines.

Myosin-10, also known as non-muscle myosin IIB, is a cytoskeletal protein implicated in cardiac development and disease. In humans, it is encoded by the MYH10 gene. Using CRISPR/Cas9 gene editing technology, we generated two MYH10 knockout human iPSC lines - one heterozygous (MRli003-A-1) and one homozygous (MRli003-A-2) - by introducing a frameshift deletion in exon 2.

Clinical manifestations in primary ciliary dyskinesia: systematic review and meta-analysis.

Few original studies have described the prevalence and severity of clinical symptoms of primary ciliary dyskinesia (PCD). This systematic review and meta-analysis aimed to identify all published studies on clinical manifestations of PCD patients, and to describe their prevalence and severity stratified by age and sex.We searched PubMed, Embase and Scopus for studies describing clinical symptoms of ≥10 patients with PCD.