Graft conditioning with fluticasone propionate reduces graft-versus-host disease upon allogeneic hematopoietic cell transplantation in mice.

Hematopoietic cell transplantation (HCT) treats many blood conditions but remains underused due to complications such as graft-versus-host disease (GvHD). In GvHD, donor immune cells attack the patient, requiring powerful immunosuppressive drugs like glucocorticoids (GCs) to prevent death. In this study, we tested the hypothesis that donor cell conditioning with the glucocorticoid fluticasone propionate (FLU) prior to transplantation could increase hematopoietic stem cell (HSC) engraftment and reduce GvHD.

Single-tube collection and nucleic acid analysis of clinical samples for SARS-CoV-2 saliva testing.

The SARS-CoV-2 pandemic has brought to light the need for expedient diagnostic testing. Cost and availability of large-scale testing capacity has led to a lag in turnaround time and hindered contact tracing efforts, resulting in a further spread of SARS-CoV-2. To increase the speed and frequency of testing, we developed a cost-effective single-tube approach for collection, denaturation, and analysis of clinical samples.

MAC2 is a long-lasting marker of peripheral cell infiltrates into the mouse CNS after bone marrow transplantation and coronavirus infection.

Microglia are the primary resident myeloid cells of the brain responsible for maintaining homeostasis and protecting the central nervous system (CNS) from damage and infection. Monocytes and monocyte-derived macrophages arising from the periphery have also been implicated in CNS pathologies, however, distinguishing between different myeloid cell populations in the CNS has been difficult. Here, we set out to develop a reliable histological marker that can assess distinct myeloid cell heterogeneity and functional contributions, particularly in the context of disease and/or neuroinflammation.

Absence of CD11a Expression Identifies Embryonic Hematopoietic Stem Cell Precursors Competitive Neonatal Transplantation Assay.

Hematopoietic stem cells (HSCs) are defined by their self-renewal, multipotency, and bone marrow (BM) engraftment abilities. How HSCs emerge during embryonic development remains unclear, but are thought to arise from hemogenic endothelium through an intermediate precursor called "pre-HSCs." Pre-HSCs have self-renewal and multipotent activity, but lack BM engraftability.

Subventricular zone/white matter microglia reconstitute the empty adult microglial niche in a dynamic wave.

Microglia, the brain's resident myeloid cells, play central roles in brain defense, homeostasis, and disease. Using a prolonged colony-stimulating factor 1 receptor inhibitor (CSF1Ri) approach, we report an unprecedented level of microglial depletion and establish a model system that achieves an empty microglial niche in the adult brain. We identify a myeloid cell that migrates from the subventricular zone and associated white matter areas.

Author Correction: Gene correction for SCID-X1 in long-term hematopoietic stem cells.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Author Correction: Gene correction for SCID-X1 in long-term hematopoietic stem cells.

The original version of this Article omitted the following from the Acknowledgements: "G.B. acknowledges the support from the Cancer Prevention and Research Institute of Texas (RR140081 and RR170721).

Gene correction for SCID-X1 in long-term hematopoietic stem cells.

Gene correction in human long-term hematopoietic stem cells (LT-HSCs) could be an effective therapy for monogenic diseases of the blood and immune system. Here we describe an approach for X-linked sSevere cCombined iImmunodeficiency (SCID-X1) using targeted integration of a cDNA into the endogenous start codon to functionally correct disease-causing mutations throughout the gene. Using a CRISPR-Cas9/AAV6 based strategy, we achieve up to 20% targeted integration frequencies in LT-HSCs.

Induction of Mesoderm and Neural Crest-Derived Pericytes from Human Pluripotent Stem Cells to Study Blood-Brain Barrier Interactions.

In the CNS, perivascular cells ("pericytes") associate with endothelial cells to mediate the formation of tight junctions essential to the function of the blood-brain barrier (BBB). The BBB protects the CNS by regulating the flow of nutrients and toxins into and out of the brain. BBB dysfunction has been implicated in the progression of Alzheimer's disease (AD), but the role of pericytes in BBB dysfunction in AD is not well understood.

CD11a expression distinguishes infiltrating myeloid cells from plaque-associated microglia in Alzheimer's disease.

Alzheimer's disease (AD) is the leading cause of age-related neurodegeneration and is characterized neuropathologically by the accumulation of insoluble beta-amyloid (Aβ) peptides. In AD brains, plaque-associated myeloid (PAM) cells cluster around Aβ plaques but fail to effectively clear Aβ by phagocytosis. PAM cells were originally thought to be brain-resident microglia.

The CD11a and Endothelial Protein C Receptor Marker Combination Simplifies and Improves the Purification of Mouse Hematopoietic Stem Cells.

Hematopoietic stem cells (HSCs) are the self-renewing multipotent progenitors to all blood cell types. Identification and isolation of HSCs for study has depended on the expression of combinations of surface markers on HSCs that reliably distinguish them from other cell types. However, the increasing number of markers required to isolate HSCs has made it tedious, expensive, and difficult for newcomers, suggesting the need for a simpler panel of HSC markers.

LYVE1 Marks the Divergence of Yolk Sac Definitive Hemogenic Endothelium from the Primitive Erythroid Lineage.

The contribution of the different waves and sites of developmental hematopoiesis to fetal and adult blood production remains unclear. Here, we identify lymphatic vessel endothelial hyaluronan receptor-1 (LYVE1) as a marker of yolk sac (YS) endothelium and definitive hematopoietic stem and progenitor cells (HSPCs). Endothelium in mid-gestation YS and vitelline vessels, but not the dorsal aorta and placenta, were labeled by Lyve1-Cre.

The adaptive immune system restrains Alzheimer's disease pathogenesis by modulating microglial function.

The innate immune system is strongly implicated in the pathogenesis of Alzheimer's disease (AD). In contrast, the role of adaptive immunity in AD remains largely unknown. However, numerous clinical trials are testing vaccination strategies for AD, suggesting that T and B cells play a pivotal role in this disease.

CD201 and CD27 identify hematopoietic stem and progenitor cells across multiple murine strains independently of Kit and Sca-1.

Identification and isolation of hematopoietic stem cells (HSCs) in mice is most commonly based on the expression of surface molecules Kit and Sca-1 and the absence of markers of mature lineages. However, Sca-1 is absent or weakly expressed in hematopoietic progenitors in many strains, including nonobese diabetic (NOD), BALB/c, C3H, and CBA mice. In addition, both Kit and Sca-1 levels are modulated following bone marrow injury.

4-Hydroxytamoxifen probes for light-dependent spatiotemporal control of Cre-ER mediated reporter gene expression.

The tamoxifen inducible Cre-ER/loxP system provides tissue specific temporal control of gene recombination events, and can be used to induce expression of reporter genes (e.g. GFP, LacZ) for lineage tracing studies.

Upregulation of CD11A on hematopoietic stem cells denotes the loss of long-term reconstitution potential.

Small numbers of hematopoietic stem cells (HSCs) generate large numbers of mature effector cells through the successive amplification of transiently proliferating progenitor cells. HSCs and their downstream progenitors have been extensively characterized based on their cell-surface phenotype and functional activities during transplantation assays. These cells dynamically lose and acquire specific sets of surface markers during differentiation, leading to the identification of markers that allow for more refined separation of HSCs from early hematopoietic progenitors.

Quiescent hematopoietic stem cells accumulate DNA damage during aging that is repaired upon entry into cell cycle.

Hematopoietic stem cells (HSCs) maintain homeostasis and regenerate the blood system throughout life. It has been postulated that HSCs may be uniquely capable of preserving their genomic integrity in order to ensure lifelong function. To directly test this, we quantified DNA damage in HSCs and downstream progenitors from young and old mice, revealing that strand breaks significantly accrue in HSCs during aging.

Identification of multipotent progenitors that emerge prior to hematopoietic stem cells in embryonic development.

Hematopoiesis in the embryo proceeds in a series of waves, with primitive erythroid-biased waves succeeded by definitive waves, within which the properties of hematopoietic stem cells (multilineage potential, self-renewal, and engraftability) gradually arise. Whereas self-renewal and engraftability have previously been examined in the embryo, multipotency has not been thoroughly addressed, especially at the single-cell level or within well-defined populations. To identify when and where clonal multilineage potential arises during embryogenesis, we developed a single-cell multipotency assay.

Anti-CD47 antibody-mediated phagocytosis of cancer by macrophages primes an effective antitumor T-cell response.

Mobilization of the T-cell response against cancer has the potential to achieve long-lasting cures. However, it is not known how to harness antigen-presenting cells optimally to achieve an effective antitumor T-cell response. In this study, we show that anti-CD47 antibody-mediated phagocytosis of cancer by macrophages can initiate an antitumor T-cell immune response.

Synthesis of a photocaged tamoxifen for light-dependent activation of Cre-ER recombinase-driven gene modification.

We report the design of a water-soluble, quaternized tamoxifen photoprobe and demonstrate its application in light-controlled induction of green fluorescent protein expression via a Cre-ER recombinase system.

Prospective isolation of human embryonic stem cell-derived cardiovascular progenitors that integrate into human fetal heart tissue.

A goal of regenerative medicine is to identify cardiovascular progenitors from human ES cells (hESCs) that can functionally integrate into the human heart. Previous studies to evaluate the developmental potential of candidate hESC-derived progenitors have delivered these cells into murine and porcine cardiac tissue, with inconclusive evidence regarding the capacity of these human cells to physiologically engraft in xenotransplantation assays. Further, the potential of hESC-derived cardiovascular lineage cells to functionally couple to human myocardium remains untested and unknown.

Gene Expression Commons: an open platform for absolute gene expression profiling.

Gene expression profiling using microarrays has been limited to comparisons of gene expression between small numbers of samples within individual experiments. However, the unknown and variable sensitivities of each probeset have rendered the absolute expression of any given gene nearly impossible to estimate. We have overcome this limitation by using a very large number (>10,000) of varied microarray data as a common reference, so that statistical attributes of each probeset, such as the dynamic range and threshold between low and high expression, can be reliably discovered through meta-analysis.

Identification of the earliest natural killer cell-committed progenitor in murine bone marrow.

Natural killer (NK) cells develop in the bone marrow and are known to gradually acquire the ability to eliminate infected and malignant cells, yet the cellular stages of NK lineage commitment and maturation are incompletely understood. Using 12-color flow cytometry, we identified a novel NK-committed progenitor (pre-NKP) that is a developmental intermediate between the upstream common lymphoid progenitor and the downstream NKP, previously assumed to represent the first stage of NK lineage commitment. Our analysis also refined the purity of NKPs (rNKP) by 6-fold such that 50% of both pre-NKP and rNKP cells gave rise to NKp46+ NK cells at the single-cell level.

An antibody against SSEA-5 glycan on human pluripotent stem cells enables removal of teratoma-forming cells.

An important risk in the clinical application of human pluripotent stem cells (hPSCs), including human embryonic and induced pluripotent stem cells (hESCs and hiPSCs), is teratoma formation by residual undifferentiated cells. We raised a monoclonal antibody against hESCs, designated anti-stage-specific embryonic antigen (SSEA)-5, which binds a previously unidentified antigen highly and specifically expressed on hPSCs--the H type-1 glycan. Separation based on SSEA-5 expression through fluorescence-activated cell sorting (FACS) greatly reduced teratoma-formation potential of heterogeneously differentiated cultures.