Haematopoiesis in the bone marrow (BM) maintains blood and immune cell production throughout postnatal life. Haematopoiesis first emerges in human BM at 11-12 weeks after conception
, yet almost ...nothing is known about how fetal BM (FBM) evolves to meet the highly specialized needs of the fetus and newborn. Here we detail the development of FBM, including stroma, using multi-omic assessment of mRNA and multiplexed protein epitope expression. We find that the full blood and immune cell repertoire is established in FBM in a short time window of 6-7 weeks early in the second trimester. FBM promotes rapid and extensive diversification of myeloid cells, with granulocytes, eosinophils and dendritic cell subsets emerging for the first time. The substantial expansion of B lymphocytes in FBM contrasts with fetal liver at the same gestational age. Haematopoietic progenitors from fetal liver, FBM and cord blood exhibit transcriptional and functional differences that contribute to tissue-specific identity and cellular diversification. Endothelial cell types form distinct vascular structures that we show are regionally compartmentalized within FBM. Finally, we reveal selective disruption of B lymphocyte, erythroid and myeloid development owing to a cell-intrinsic differentiation bias as well as extrinsic regulation through an altered microenvironment in Down syndrome (trisomy 21).
Full text
Available for:
GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
Macrophages are the first cells of the nascent immune system to emerge during embryonic development. In mice, embryonic macrophages infiltrate developing organs, where they differentiate ...symbiotically into tissue-resident macrophages (TRMs)
. However, our understanding of the origins and specialization of macrophages in human embryos is limited. Here we isolated CD45
haematopoietic cells from human embryos at Carnegie stages 11 to 23 and subjected them to transcriptomic profiling by single-cell RNA sequencing, followed by functional characterization of a population of CD45
CD34
CD44
yolk sac-derived myeloid-biased progenitors (YSMPs) by single-cell culture. We also mapped macrophage heterogeneity across multiple anatomical sites and identified diverse subsets, including various types of embryonic TRM (in the head, liver, lung and skin). We further traced the specification trajectories of TRMs from either yolk sac-derived primitive macrophages or YSMP-derived embryonic liver monocytes using both transcriptomic and developmental staging information, with a focus on microglia. Finally, we evaluated the molecular similarities between embryonic TRMs and their adult counterparts. Our data represent a comprehensive characterization of the spatiotemporal dynamics of early macrophage development during human embryogenesis, providing a reference for future studies of the development and function of human TRMs.
Full text
Available for:
IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
Neurogenesis is known to persist in the adult mammalian central nervous system (CNS). The identity of the cells that generate new neurons in the postnatal CNS has become a crucial but elusive issue. ...Using a transgenic mouse, we show that NG2 proteoglycan-positive progenitor cells that express the 2′,3′-cyclic nucleotide 3′-phosphodiesterase gene display a multipotent phenotype in vitro and generate electrically excitable neurons, as well as astrocytes and oligodendrocytes. The fast kinetics and the high rate of multipotent fate of these NG2+ progenitors in vitro reflect an intrinsic property, rather than reprogramming. We demonstrate in the hippocampus in vivo that a sizeable fraction of postnatal NG2+ progenitor cells are proliferative precursors whose progeny appears to differentiate into GABAergic neurons capable of propagating action potentials and displaying functional synaptic inputs. These data show that at least a subpopulation of postnatal NG2-expressing cells are CNS multipotent precursors that may underlie adult hippocampal neurogenesis.
Full text
Available for:
BFBNIB, NUK, PNG, UL, UM, UPUK
The human kidney contains up to 2 million epithelial nephrons responsible for blood filtration. Regenerating the kidney requires the induction of the more than 20 distinct cell types required for ...excretion and the regulation of pH, and electrolyte and fluid balance. We have previously described the simultaneous induction of progenitors for both collecting duct and nephrons via the directed differentiation of human pluripotent stem cells. Paradoxically, although both are of intermediate mesoderm in origin, collecting duct and nephrons have distinct temporospatial origins. Here we identify the developmental mechanism regulating the preferential induction of collecting duct versus kidney mesenchyme progenitors. Using this knowledge, we have generated kidney organoids that contain nephrons associated with a collecting duct network surrounded by renal interstitium and endothelial cells. Within these organoids, individual nephrons segment into distal and proximal tubules, early loops of Henle, and glomeruli containing podocytes elaborating foot processes and undergoing vascularization. When transcription profiles of kidney organoids were compared to human fetal tissues, they showed highest congruence with first trimester human kidney. Furthermore, the proximal tubules endocytose dextran and differentially apoptose in response to cisplatin, a nephrotoxicant. Such kidney organoids represent powerful models of the human organ for future applications, including nephrotoxicity screening, disease modelling and as a source of cells for therapy.
Full text
Available for:
IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
The process of hematopoiesis is subject to substantial ontogenic remodeling that is accompanied by alterations in cellular fate during both development and disease. We combine state-of-the-art mass ...spectrometry with extensive functional assays to gain insight into ontogeny-specific proteomic mechanisms regulating hematopoiesis. Through deep coverage of the cellular proteome of fetal and adult lympho-myeloid multipotent progenitors (LMPPs), common lymphoid progenitors (CLPs), and granulocyte-monocyte progenitors (GMPs), we establish that features traditionally attributed to adult hematopoiesis are conserved across lymphoid and myeloid lineages, whereas generic fetal features are suppressed in GMPs. We reveal molecular and functional evidence for a diminished granulocyte differentiation capacity in fetal LMPPs and GMPs relative to their adult counterparts. Our data indicate an ontogeny-specific requirement of myosin activity for myelopoiesis in LMPPs. Finally, we uncover an ontogenic shift in the monocytic differentiation capacity of GMPs, partially driven by a differential expression of Irf8 during fetal and adult life.
Display omitted
•>4,000 proteins quantified in fetal and adult hematopoietic progenitor cells (HPCs)•Protein expression in HPCs separates cells based on ontogenic stage and lineage potential•Generic fetal features are suppressed in myeloid-restricted progenitors•Low Irf8 expression partially drives an impairment in monopoiesis in fetal HPCs
Jassinskaja et al. describe ontogeny-specific proteomic signatures and functionality of lineage-biased hematopoietic progenitor cells (HPCs). They uncover that fetal-specific features differ between lymphoid-competent and myeloid-restricted progenitors and reveal an ontogenic shift in monocyte differentiation capacity, partially driven by differential Irf8 expression between fetal and adult granulocyte-monocyte progenitors (GMPs).
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The molecular characterization of immune subsets is important for designing effective strategies to understand and treat diseases. We characterized 29 immune cell types within the peripheral blood ...mononuclear cell (PBMC) fraction of healthy donors using RNA-seq (RNA sequencing) and flow cytometry. Our dataset was used, first, to identify sets of genes that are specific, are co-expressed, and have housekeeping roles across the 29 cell types. Then, we examined differences in mRNA heterogeneity and mRNA abundance revealing cell type specificity. Last, we performed absolute deconvolution on a suitable set of immune cell types using transcriptomics signatures normalized by mRNA abundance. Absolute deconvolution is ready to use for PBMC transcriptomic data using our Shiny app (https://github.com/giannimonaco/ABIS). We benchmarked different deconvolution and normalization methods and validated the resources in independent cohorts. Our work has research, clinical, and diagnostic value by making it possible to effectively associate observations in bulk transcriptomics data to specific immune subsets.
Display omitted
•Characterization of 29 human immune cell type by RNA-seq and flow cytometry•Modules of specific, co-expressed, and housekeeping genes are defined•The mRNA heterogeneity and abundance are cell type specific•The proposed normalization approach enables absolute deconvolution
Monaco et al. generate an RNA-seq dataset on 29 immune cell types and identify modules of cell type-specific, co-expressed, and housekeeping genes. The mRNA heterogeneity and abundance of the different cell types were examined. Absolute deconvolution of PBMCs was obtained by taking into account mRNA abundance when normalizing the signature matrix.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In vitro models of the developing brain such as three-dimensional brain organoids offer an unprecedented opportunity to study aspects of human brain development and disease. However, the cells ...generated within organoids and the extent to which they recapitulate the regional complexity, cellular diversity and circuit functionality of the brain remain undefined. Here we analyse gene expression in over 80,000 individual cells isolated from 31 human brain organoids. We find that organoids can generate a broad diversity of cells, which are related to endogenous classes, including cells from the cerebral cortex and the retina. Organoids could be developed over extended periods (more than 9 months), allowing for the establishment of relatively mature features, including the formation of dendritic spines and spontaneously active neuronal networks. Finally, neuronal activity within organoids could be controlled using light stimulation of photosensitive cells, which may offer a way to probe the functionality of human neuronal circuits using physiological sensory stimuli.
Full text
Available for:
IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
The liver is the largest solid organ in the body and is critical for metabolic and immune functions. However, little is known about the cells that make up the human liver and its immune ...microenvironment. Here we report a map of the cellular landscape of the human liver using single-cell RNA sequencing. We provide the transcriptional profiles of 8444 parenchymal and non-parenchymal cells obtained from the fractionation of fresh hepatic tissue from five human livers. Using gene expression patterns, flow cytometry, and immunohistochemical examinations, we identify 20 discrete cell populations of hepatocytes, endothelial cells, cholangiocytes, hepatic stellate cells, B cells, conventional and non-conventional T cells, NK-like cells, and distinct intrahepatic monocyte/macrophage populations. Together, our study presents a comprehensive view of the human liver at single-cell resolution that outlines the characteristics of resident cells in the liver, and in particular provides a map of the human hepatic immune microenvironment.
Mesenchymal stem cells occupy niches in stromal tissues where they provide sources of cells for specialized mesenchymal derivatives during growth and repair. The origins of mesenchymal stem cells ...have been the subject of considerable discussion, and current consensus holds that perivascular cells form mesenchymal stem cells in most tissues. The continuously growing mouse incisor tooth offers an excellent model to address the origin of mesenchymal stem cells. These stem cells dwell in a niche at the tooth apex where they produce a variety of differentiated derivatives. Cells constituting the tooth are mostly derived from two embryonic sources: neural crest ectomesenchyme and ectodermal epithelium. It has been thought for decades that the dental mesenchymal stem cells giving rise to pulp cells and odontoblasts derive from neural crest cells after their migration in the early head and formation of ectomesenchymal tissue. Here we show that a significant population of mesenchymal stem cells during development, self-renewal and repair of a tooth are derived from peripheral nerve-associated glia. Glial cells generate multipotent mesenchymal stem cells that produce pulp cells and odontoblasts. By combining a clonal colour-coding technique with tracing of peripheral glia, we provide new insights into the dynamics of tooth organogenesis and growth.
Full text
Available for:
IJS, KISLJ, NUK, UL, UM, UPUK
Dendritic cells (DCs) in lymphoid tissue arise from precursors that also produce monocytes and plasmacytoid DCs (pDCs). Where DC and monocyte lineage commitment occurs and the nature of the DC ...precursor that migrates from the bone marrow to peripheral lymphoid organs are unknown. We show that DC development progresses from the macrophage and DC precursor to common DC precursors that give rise to pDCs and classical spleen DCs (cDCs), but not monocytes, and finally to committed precursors of cDCs (pre-cDCs). Pre-cDCs enter lymph nodes through and migrate along high endothelial venules and later disperse and integrate into the DC network. Further cDC development involves cell division, which is controlled in part by regulatory T cells and fms-like tyrosine kinase receptor-3.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
PDF
