ABSTRACT
Hematopoietic stem cells (HSCs) produce all essential cellular components of the blood. Stromal cell lines supporting HSCs follow a vascular smooth muscle cell (vSMC) differentiation pathway, suggesting that some hematopoiesis-supporting cells originate from vSMC precursors. These pericyte-like precursors were recently identified in the aorta-gonad-mesonephros (AGM) region; however, their role in the hematopoietic development in vivo remains unknown. Here, we identify a subpopulation of NG2+Runx1+ perivascular cells that display a sclerotome-derived vSMC transcriptomic profile. We show that deleting Runx1 in NG2+ cells impairs the hematopoietic development in vivo and causes transcriptional changes in pericytes/vSMCs, endothelial cells and hematopoietic cells in the murine AGM. Importantly, this deletion leads also to a significant reduction of HSC reconstitution potential in the bone marrow in vivo. This defect is developmental, as NG2+Runx1+ cells were not detected in the adult bone marrow, demonstrating the existence of a specialised pericyte population in the HSC-generating niche, unique to the embryo.
Subject(s)
Endothelial Cells , Muscle, Smooth, Vascular , Mice , Animals , Muscle, Smooth, Vascular/metabolism , Endothelial Cells/metabolism , Cell Differentiation , Hematopoietic Stem Cells/metabolism , Hematopoiesis/genetics , Mesonephros , Gonads/metabolism , Core Binding Factor Alpha 2 Subunit/genetics , Core Binding Factor Alpha 2 Subunit/metabolismABSTRACT
Mesenchymal stem/stromal cells (MSCs) can differentiate into osteoblasts under appropriate conditions. PDGFRß signaling controls MSC osteogenic potential both transcriptomically and in culture. Here, we present a "computer to the bench" protocol to analyze changes in MSC osteogenic potential at transcriptomic and cellular level in the absence of PDGFRß. We detail the preparation of cells from mouse embryos, the analysis of transcriptomic changes from single-cell RNA-sequencing data, the procedure for MSC derivation and culture, and an osteogenic assay for functional validation. For complete details on the use and execution of this protocol, please refer to Sá da Bandeira et al. (2022).1.
Subject(s)
Mesenchymal Stem Cells , Transcriptome , Animals , Mice , Transcriptome/genetics , Cell Differentiation/genetics , Osteogenesis/genetics , Gene Expression ProfilingABSTRACT
Hematopoietic stem cell (HSC) generation in the aorta-gonad-mesonephros region requires HSC specification signals from the surrounding microenvironment. In zebrafish, PDGF-B/PDGFRß signaling controls hematopoietic stem/progenitor cell (HSPC) generation and is required in the HSC specification niche. Little is known about murine HSPC specification in vivo and whether PDGF-B/PDGFRß is involved. Here, we show that PDGFRß is expressed in distinct perivascular stromal cell layers surrounding the mid-gestation dorsal aorta, and its deletion impairs hematopoiesis. We demonstrate that PDGFRß+ cells play a dual role in murine hematopoiesis. They act in the aortic niche to support HSPCs, and in addition, PDGFRß+ embryonic precursors give rise to a subset of HSPCs that persist into adulthood. These findings provide crucial information for the controlled production of HSPCs in vitro.
Subject(s)
Mesonephros , Zebrafish , Animals , Hematopoiesis , Hematopoietic Stem Cells , Mice , Receptor, Platelet-Derived Growth Factor beta , Stromal CellsABSTRACT
Historically, qualitative research has complemented quantitative biologic and epidemiologic studies to provide a more complete understanding of pandemics. The COVID-19 pandemic has generated unique and novel challenges for qualitative researchers, who have embraced creative solutions including virtual focus groups and rapid analyses to continue their work. We present our experience conducting a multilingual global qualitative study of healthcare resilience among teams of pediatric oncology professionals during the COVID-19 pandemic. We provide an in-depth description of our methodology and an analysis of factors we believe contributed to our study's success including our use of technology, engagement of a large multilingual team, global partnerships, and framework-based rapid analysis. We hope these techniques may be useful to qualitative researchers conducting studies during the current pandemic, as well as for all pediatric oncology studies including multiple languages or geographically disparate subjects.
