Biology subjects

Muratore, A.

Publications and source records attributed to Muratore, A..

3 recordsLinked to original sources

bioRxiv2026

The Aorta-Gonad-Mesonephros niche shapes the functions of yolk sac-derived macrophages involved in hematopoietic stem and progenitor cell generation ex vivo

Hematopoietic stem cells (HSCs) generated from induced pluripotent stem cells (iPSCs) offer a promising patient-specific alternative to allogeneic transplantation, yet current differentiation protocols fail to fully recapitulate in vivo HSC maturation. During mouse development, yolk sac (YS)-derived macrophages populate the aorta-gonad-mesonephros (AGM) region at the time of HSC emergence, but the mechanisms by which they support ex vivo hematopoietic stem and progenitor cell (HSPC) generation remain poorly defined. Bulk RNA sequencing revealed that mature AGM CD206 macrophages upregulate pro-inflammatory cytokines and the adhesion molecule F4/80. Using F4/80 knockout embryos, we identify a previously unreported, niche-specific role for F4/80 in restraining the frequency and colony-forming activity of HSPC subsets in the AGM, while supporting endothelial cell maintenance; this effect was absent in the YS. Lineage-tracing with a Cdh5-CreERT2;Rosa26LSL-tdTomato pulse-chase system confirmed that both CD206 and CD206- AGM cells originate from early YS-derived endothelial precursors, with no evidence of local macrophage generation within the AGM. Functional co-culture assays further demonstrated that the ability of CD206 macrophages to enhance the progenitor potential of hemogenic endothelium is AGM-specific and not an intrinsic, ontogeny-determined property, as YS macrophages failed to confer the same benefit even when paired with AGM endothelial cells, and AGM macrophages were ineffective with YS endothelium. Differential expression and NicheNet ligand-receptor interaction analyses identified a small set of AGM-restricted macrophage genes - including Mmp2, Nrep, Ccl2, and Cxcl16 - which are predicted to interact with both endothelial and cluster cells during endothelial-to-hematopoietic transition. Together, these findings establish that AGM macrophages acquire niche-specific transcriptional and functional properties upon entry into the aortic microenvironment, independent of their YS origin, and identify candidate macrophage-derived factors and a novel regulatory role for F4/80 in shaping HSPC output. These insights may guide the refinement of iPSC-based HSC differentiation protocols through the targeted, temporally controlled addition of macrophage-associated signals.

developmental biology↗

bioRxiv2025

Novel markers for haemogenic endothelium and haematopoietic progenitors in the mouse yolk sac

Erythro-myeloid progenitors (EMPs) originate from the haemogenic endothelium in the yolk sac via an endothelial-to-haematopoietic transition (EHT) to generate blood and immune cells that support embryo development. Yet, the transitory nature of EHT and the limited availability of molecular markers has constrained our understanding of the origin, identity and differentiation dynamics of EMPs. Here, we have refined the annotation of yolk sac haemato-vascular populations in publicly available single-cell RNA sequencing (scRNAseq) datasets from mouse embryos to identify novel molecular markers of haemogenic endothelium and EMPs. By sub-clustering key cell populations followed by pseudotime analysis, we refined cluster annotations and then reconstructed differentiation trajectories. Subsequent differential gene expression analysis between clusters identified novel cell surface markers for haemogenic endothelial cells (Fxyd5 and Scarf1) and EMPs (Fcer1g, Tyrobp and Mctp1). Further, we have identified candidate signalling and metabolic pathways that may regulate yolk sac haematopoietic emergence and differentiation. The specificity of FXYD5, SCARF1 and FCER1G for haemogenic endothelium and EMPs was validated by immunostaining of mouse yolk sac. These insights into the transcriptional dynamics in the yolk sac should support future investigation of EHT and haematopoietic differentiation during early mammalian development.

developmental biology↗

bioRxiv2024

Hemogenic endothelium of the vitelline and umbilical arteries is the major contributor to mouse fetal lympho-myelopoiesis

Embryonic hematopoiesis consists of distinct waves originating in rapid succession from different anatomical locations. Hematopoietic progenitors appearing earlier than definitive hematopoietic stem cells (HSCs) play key roles in fetal and postnatal life. However, their precise origin, identity and the extent of their contribution need further clarification. To this aim, we took advantage of a genetic fate-mapping strategy in mice that allows labeling and tracking of distinct subsets of hemogenic endothelium (HE). Time-course labeling of hematopoietic progenitors emerging from HE between E8.5 and E9.5, before intra-embryonic definitive HSC generation, revealed a major fetal lympho-myeloid contribution which declined in the adult. Lineage tracing coupled with whole-mount imaging and single-cell RNA sequencing located its source within hematopoietic clusters of vitelline and umbilical arteries. Functional assays confirmed the transient nature of these progenitors. We therefore unveiled a hitherto unidentified early wave of fetal-restricted hematopoietic stem/progenitor cells poised for differentiation that provide a major contribution to pre-natal hematopoiesis.

developmental biology↗