Quality assurance of hematopoietic stem cells by macrophages determines stem cell clonality

Wattrus et al. establish that hematopoietic stem and progenitor cells (HSPC) are quality assured for stress levels during development. Calreticulin is revealed as an “eat-me” molecule that initiates macrophage-HSPC interaction and leads to programmed cell clearance or stem cell expansion. They used SORT-seq to characterize the macrophage and HSPC subpopulations involved.

Inflammatory response in hematopoietic stem and progenitor cells triggered by activating SHP2 mutations evokes blood defects

Hematopoietic stem and progenitor cells (HSPCs) are the disease-propagating cells of juvenile myelomonocytic leukemia (JMML). A SHP2 mutation is common in these patients, and Solman et al. reproduced it in zebrafish. Single-cell mRNA sequencing of HSPCs from mutant zebrafish embryos and bulk sequencing of HSPCs from JMML patients revealed an overlapping inflammatory gene expression pattern. Pharmacological inhibition of the inflammatory response positively impacted mutant zebrafish, suggesting therapeutic possibilities in JMML patients.

Hand2 delineates mesothelium progenitors and is reactivated in mesothelioma

Prummel et al. studied the early embryonic origins of mesothelia in zebrafish, mice, and humans. Single-cell RNA sequencing of zebrafish early lateral plate mesoderm revealed a heterogeneous progenitor pool. Hand2 was found as a marker for mesothelial progenitors. These progenitors form visceral and parietal mesothelium.

Cell Type Purification by Single-Cell Transcriptome-Trained Sorting

This paper presents GateID, a computational method that combines single-cell RNA sequencing with FACS index sorting. It uses only native cellular properties such as cell size, granularity, and mitochondrial content to purify cell types of choice, making a priori knowledge of cell type markers unneeded