Clonal and Quantitative In Vivo Assessment of Hematopoietic Stem Cell Differentiation Reveals Strong Erythroid Potential of Multipotent Cells.

Hematopoiesis is arguably one of the best understood stem cell systems; however, significant challenges remain to reach a consensus understanding of the lineage potential, heterogeneity, and relationships of hematopoietic stem and progenitor cell populations. To gain new insights, we performed quantitative analyses of mature cell production from hematopoietic stem cells (HSCs) and multiple hematopoietic progenitor populations. Assessment of the absolute numbers of mature cell types produced by each progenitor cell revealed a striking erythroid dominance of all myeloid-competent progenitors assessed, accompanied by strong platelet reconstitution.

A Transient Developmental Hematopoietic Stem Cell Gives Rise to Innate-like B and T Cells.

The generation of distinct hematopoietic cell types, including tissue-resident immune cells, distinguishes fetal from adult hematopoiesis. However, the mechanisms underlying differential cell production to generate a layered immune system during hematopoietic development are unclear. Using an irreversible lineage-tracing model, we identify a definitive hematopoietic stem cell (HSC) that supports long-term multilineage reconstitution upon transplantation into adult recipients but does not persist into adulthood in situ.

Hematopoietic stem cell-specific GFP-expressing transgenic mice generated by genetic excision of a pan-hematopoietic reporter gene.

Selective labeling of specific cell types by expression of green fluorescent protein (GFP) within the hematopoietic system would have great utility in identifying, localizing, and tracking different cell populations in flow cytometry, microscopy, lineage tracing, and transplantation assays. In this report, we describe the generation and characterization of a new transgenic mouse line with specific GFP labeling of all nucleated hematopoietic cells and platelets. This new "Vav-GFP" mouse line labels the vast majority of hematopoietic cells with GFP during both embryonic development and adulthood, with particularly high expression in hematopoietic stem and progenitor cells (HSPCs).

NK Cells Preferentially Target Tumor Cells with a Cancer Stem Cell Phenotype.

Increasing evidence supports the hypothesis that cancer stem cells (CSCs) are resistant to antiproliferative therapies, able to repopulate tumor bulk, and seed metastasis. NK cells are able to target stem cells as shown by their ability to reject allogeneic hematopoietic stem cells but not solid tissue grafts. Using multiple preclinical models, including NK coculture (autologous and allogeneic) with multiple human cancer cell lines and dissociated primary cancer specimens and NK transfer in NSG mice harboring orthotopic pancreatic cancer xenografts, we assessed CSC viability, CSC frequency, expression of death receptor ligands, and tumor burden.

Natural killer cell subsets differentially reject embryonic stem cells based on licensing.

Background: Embryonic stem cells (ESC) and induced pluripotent stem cells provide great promise to the future of medicine. Because immune rejection represents a major obstacle to the success of all stem cell-based therapies, many recent studies have sought to determine the key immune mediators involved in ESC rejection. The role of natural killer (NK) cells and specifically the role of NK cell licensing is not well understood in ESC rejection.