SUMMARY Hematopoiesis, the process of mature blood and immune cell production, is functionally organized as a hierarchy, with self-renewing hematopoietic stem cells (HSCs) and multipotent progenitor (MPP) cells sitting at the very top1,2. Multiple models have been proposed as to what the earliest lineage choices are in these primitive hematopoietic compartments, the cellular intermediates, and the resulting lineage trees that emerge from them3–10. Given that the bulk of studies addressing lineage outcomes have been performed in the context of hematopoietic transplantation, current lineage branching models are more likely to represent roadmaps of lineage potential rather than native fate. Here, we utilize transposon (Tn) tagging to clonally trace the fates of progenitors and stem cells in unperturbed hematopoiesis. Our results describe a distinct clonal roadmap in which the megakaryocyte (Mk) lineage arises largely independently of other hematopoietic fates. Our data, combined with single cell RNAseq, identify a functional hierarchy of uni- and oligolineage producing clones within the MPP population. Finally, our results demonstrate that traditionally defined long-term HSCs (LT-HSCs) are a significant source of Mk-restricted progenitors, suggesting that the Mk-lineage is the predominant native fate of LT-HSCs. Our study provides evidence for a substantially revised roadmap for unperturbed hematopoiesis, and highlights unique properties of MPPs and HSCs in situ.

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BACKGROUND:Hyaluronic filler is a sterile, biodegradable, viscoelastic, isotonic, transparent injectable gel implant which was approved by Food and Drug Administration (FDA) 1996. It is used for face reconstruction and modelling.CASE PRESENTATION:We report the case of a 40-year-old Serbian woman who presented after surgery of cleft lip, primary and secondary palate. We performed a biphasic therapy; in the first stage in the zone semimucosis lips is initially carried incision scar tissue. The second stage is placed hyaluronan implant.CONCLUSION:This case illustrates that, although hyaluronic fillers used mainly for correction of healthy tissue can be successfully used in the treatment of postoperative scars.