Single-cell RNA sequencing of murine hearts for studying the development of the cardiac conduction system

Single cell transcriptome profiling of immune tissues from germ-free and specific pathogen-free piglet

The commensal microbiota provides immunomodulatory signals during the development, differentiation and activation of immune cells, and is crucial for maintaining host immune homeostasis. However, the systematic effects of commensal microbiota on host immunity based on large animal model at the single-cell level remain to be resolved. Here, we utilized single-cell RNA sequencing (scRNA-seq) to analyze the transcriptome profiling containing 57,720 cells from three important immune tissues [Peyer's patches (PP), mesenteric lymph node (MLN), and spleen] of germ-free (GF) and specific pathogen-free (SPF) piglet. We presented detailed description of the dataset and preliminarily identified the major cell types including immune and non-immune cells, and further annotated the immune cell subsets. This dataset provides a data mining resource for researchers involved in microbe-host interactions, and enables in-depth analysis of cell map alterations caused by the microbiota colonization during early immune development. As the first single-cell transcriptomics dataset for immune tissue of GF and SPF piglet, this provides a valuable data resource for the study of commensal microbe-host immunity regulation.

Revisiting Cardiac Biology in the Era of Single Cell and Spatial Omics

Throughout our lifetime, each beat of the heart requires the coordinated action of multiple cardiac cell types. Understanding cardiac cell biology, its intricate microenvironments, and the mechanisms that govern their function in health and disease are crucial to designing novel therapeutical and behavioral interventions. Recent advances in single-cell and spatial omics technologies have significantly propelled this understanding, offering novel insights into the cellular diversity and function and the complex interactions of cardiac tissue. This review provides a comprehensive overview of the cellular landscape of the heart, bridging the gap between suspension-based and emerging in situ approaches, focusing on the experimental and computational challenges, comparative analyses of mouse and human cardiac systems, and the rising contextualization of cardiac cells within their niches. As we explore the heart at this unprecedented resolution, integrating insights from both mouse and human studies will pave the way for novel diagnostic tools and therapeutic interventions, ultimately improving outcomes for patients with cardiovascular diseases.

Cardiac lipidomic profiles in mice undergo changes from fetus to adult

AIMS

Lipids are essential cellular components with many important biological functions. Disturbed lipid biosynthesis and metabolism has been shown to cause cardiac developmental abnormality and cardiovascular diseases. In this study, we aimed to investigate the composition and the molecular profiles of lipids in mammalian hearts between embryonic and adult stages and uncover the underlying links between lipid and cardiac development and maturation.

MATERIALS AND METHODS

We collected mouse hearts at the embryonic day 11.5 (E11.5), E15.5, and the age of 2 months, 4 months and 10 months, and performed lipidomic analysis to determine the changes of the composition, molecular species, and relative abundance of cardiac lipids between embryonic and adult stages. Additionally, we also performed the electronic microscopy and RNA sequencing in both embryonic and adult mouse hearts.

KEY FINDINGS

The relative abundances of certain phospholipids and sphingolipids including cardiolipin, phosphatidylglycerol, phosphatidylethanolamine, and ceramide, are different between embryonic and adult hearts. Such lipidomic changes are accompanied with increased densities of mitochondrial membranes and elevated expression of genes related to mitochondrial formation in adult mouse hearts. We also analyzed individual molecular species of phospholipids and sphingolipids, and revealed that the composition and distribution of lipid molecular species in hearts also change with development.

SIGNIFICANCE

Our study provides not only a lipidomic view of mammalian hearts when developing from the embryonic to the adult stage, but also a potential pool of lipid indicators for cardiac cell development and maturation.