A hallmark of adult hematopoiesis is the continuous replacement of blood cells with limited lifespans. While active hematopoietic stem cell (HSC) contribution to multilineage hematopoiesis is the foundation of clinical HSC transplantation, recent reports have questioned the physiological contribution of HSCs to normal/steady-state adult hematopoiesis. Here, we use inducible lineage tracing from genetically marked adult HSCs and reveal robust HSC-derived multilineage hematopoiesis. This commences via defined progenitor cells, but varies substantially in between different hematopoietic lineages. By contrast, adult HSC contribution to hematopoietic cells with proposed fetal origins is neglible. Finally, we establish that the HSC contribution to multilineage hematopoiesis declines with increasing age. Therefore, while HSCs are active contributors to native adult hematopoiesis, it appears that the numerical increase of HSCs is a physiologically relevant compensatory mechanism to account for their reduced differentiation capacity with age Overall design: Lineage tracing from adult/aged HSCs in steady state
Murine HSCs contribute actively to native hematopoiesis but with reduced differentiation capacity upon aging.
Age, Specimen part, Cell line, Subject
View SamplesBackground: Skin aging is associated with intrinsic processes that compromise structure of the extracellular matrix while promoting loss of functional and regenerative capacity. These processes are accompanied by a large-scale shift in gene expression, but underlying mechanisms are not understood and conservation of these mechanisms between humans and mice is uncertain. Results: We used genome-wide expression profiling to investigate the aging skin transcriptome. In humans, age-related shifts in gene expression were sex-specific. In females, aging increased expression of transcripts associated with T-cells, B-cells and dendritic cells, and decreased expression of genes in regions with elevated Zeb1, AP-2 and YY1 motif density. In males, however, these effects were contrasting or absent. When age-associated gene expression patterns in human skin were compared to those in tail skin from CB6F1 mice, overall human-mouse correspondence was weak. Moreover, inflammatory gene expression patterns were not induced with aging of mouse tail skin, and well-known aging biomarkers were in fact decreased (e.g., Clec7a, Lyz1 and Lyz2). These unexpected patterns and weak human-mouse correspondence may be due to decreased abundance of antigen presenting cells in mouse tail skin with age. Conclusions: Aging is generally associated with a pro-inflammatory state, but we have identified an exception to this pattern with aging of CB6F1 mouse tail skin. Aging therefore does not uniformly heighten inflammatory status across all mouse tissues. Furthermore, we identified both intercellular and intracellular mechanisms of transcriptome aging, including those that are sex- and species-specific.
Meta-profiles of gene expression during aging: limited similarities between mouse and human and an unexpectedly decreased inflammatory signature.
Sex, Age, Specimen part
View SamplesIn a transcriptome study of psoriatic (PP) vs. normal (NN) skin, we found a co-expressed gene module (N5) enriched 11.5-fold for lipid biosynthetic genes. We also observed fewer visible hairs in PP skin, compared to uninvolved (PN) or NN skin (p<0.0001). To ask whether these findings might be due to abnormalities of the pilosebaceous unit, we carried out 3D morphometric analysis of paired PP and PN biopsies. Sebaceous glands (SG) were markedly atrophic in PP vs. PN skin (91% average reduction in volume, p=0.031). Module N5 genes were strongly downregulated in PP vs. NN skin (fold-change [FC] < 0.25, 44.4-fold), and strongly up-regulated in sebaceous hyperplasia (SH, FC > 4, 54.1-fold). The intersection of PP-downregulated and SH-upregulated gene lists generated a gene expression signature consisting solely of module N5 genes, whose expression in PP vs. NN skin was inversely correlated with the signature of IL17-stimuated keratinocytes. Despite loss of visible hairs, morphometry identified elongated follicles in PP vs. PN skin (average 1.7 vs. 1.2 Jm, p=0.020). These results document SG atrophy in non-scalp psoriasis, identify a cytokine-regulated set of SG signature genes, and suggest that loss of visible hair in PP skin may result from abnormal SG function.
Sebaceous Gland Atrophy in Psoriasis: An Explanation for Psoriatic Alopecia?
Specimen part, Disease, Disease stage
View SamplesKeratinocyte (KC) hyper-proliferation and epidermal thickening are characteristic features of psoriasis lesions, but the specific contributions of KCs to plaque formation are not fully understood. This study used RNA-seq to investigate the transcriptome of primary monolayer KC cultures grown from lesional (PP) and non-lesional (PN) biopsies of psoriasis patients and control subjects (NN). Whole skin biopsies from the same subjects were evaluated concurrently. RNA-seq analysis of whole skin identified a larger number of psoriasis-increased differentially expressed genes (DEGs), but analysis of KC cultures identified more PP- and PN-decreased DEGs. These latter DEG sets overlapped more strongly with genes near loci identified by psoriasis genome-wide association studies and were enriched for genes associated with epidermal differentiation. Consistent with this, the frequency of AP-1 motifs was elevated in regions upstream of PN-KC-decreased DEGs. A subset of these genes belonged to the same co-expression module, mapped to the epidermal differentiation complex, and exhibited differentiation-dependent expression. These findings demonstrate a decreased differentiation gene signature in PP/PN-KCs that had not been identified by pre-genomic studies of patient-derived monolayers. This may reflect intrinsic defects limiting psoriatic KC differentiation capacity, which may contribute to compromised barrier function in normal-appearing uninvolved psoriatic skin. Overall design: Samples were obtained from lesional skin of psoriasis patients (PP), uninvolved skin of psoriasis patients (PN), and normal skin from control individuals (NN). RNA was extracted from full-thickness skin biopsies of keratinocytes (KCs) grown as monolayer cutures. Samples were obtained from 4 psoriasis patients (individuals 1 - 4) and 4 control subjects (individuals 5 - 8).
RNA-seq identifies a diminished differentiation gene signature in primary monolayer keratinocytes grown from lesional and uninvolved psoriatic skin.
Specimen part, Subject
View SamplesHere we provide fundamental insights into early human development by single-cell RNA-sequencing of human and mouse preimplantation embryos. We elucidate conserved transcriptional programs along with those that are human-specific. Importantly, we validate our RNA-sequencing findings at the protein level, which further reveals differences in human and mouse embryo gene expression. For example, we identify several genes exclusively expressed in the human pluripotent epiblast including the transcription factor KLF17. Key components of the TGF-ß signaling pathway including NODAL, GDF3, TGFBR1/ALK5, LEFTY1, SMAD2, SMAD4 and TDGF1 are also enriched in the human epiblast. Intriguingly, inhibition of TGF-ß signaling abrogates NANOG expression in human epiblast cells, consistent with a requirement for this pathway in pluripotency. Although key trophectoderm factors Id2, Elf5, and Eomes are exclusively localized to this lineage in the mouse, the human orthologues are either absent or expressed in alternative lineages. Importantly, we also identify genes with conserved expression dynamics including Foxa2/FOXA2, which we show is restricted to the primitive endoderm in both human and mouse embryos. Comparisons of the human epiblast to existing embryonic stem cells (hESCs) reveals conservation of pluripotency but also additional pathways more enriched in hESCs. Our analysis highlights significant differences in human preimplantation development compared to mouse and provides a molecular blueprint to understand human embryogenesis and its relationship to stem cells. Overall design: Single-Cell RNA-seq
Defining the three cell lineages of the human blastocyst by single-cell RNA-seq.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Sex and strain dependent differences in mucosal immunology and microbiota composition in mice.
Sex, Specimen part
View SamplesThe clinical features of psoriasis, characterized by sharply demarcated scaly erythematous plaques, are typically so distinctive that a diagnosis can easily be made on these grounds alone. However, there is great variability in treatment response between individual patients, and this may reflect heterogeneity of inflammatory networks driving the disease. In this study, whole-genome transcriptional profiling was used to characterize inflammatory and cytokine networks in 62 lesional skin samples obtained from patients with stable chronic plaque psoriasis. We were able to stratify lesions according to their inflammatory gene expression signatures, identifying those associated with strong (37% of patients), moderate (39%) and weak inflammatory infiltrates (24%). Additionally, we identified differences in cytokine signatures with heightened cytokine-response patterns in one sub-group of lesions (IL-13-strong; 50%) and attenuation of these patterns in a second sub-group (IL-13-weak; 50%). These sub-groups correlated with the composition of the inflammatory infiltrate, but were only weakly associated with increased risk allele frequency at some psoriasis susceptibility loci (e.g., REL, TRAF3IP2 and NOS2). Our findings highlight variable points in the inflammatory and cytokine networks known to drive chronic plaque psoriasis. Such heterogeneous aspects may shape clinical course and treatment responses, and can provide avenues for development of personalized treatments.
Heterogeneity of inflammatory and cytokine networks in chronic plaque psoriasis.
Specimen part, Treatment
View SamplesA dysbiosis in the intestinal microbiome plays a role in the pathogenesis of several immunological diseases. These diseases often show a gender bias, suggesting gender differences in immune responses and in the intestinal microbiome. We hypothesized that gender differences in immune responses are associated with gender differences in microbiota. We demonstrated mouse strain dependent gender differences in the intestinal microbiome. Interestingly, a cluster of colonic genes (related to humoral and cell-mediated immune responses) correlated oppositely with microbiota species abundant in B6 females and in BALB/c males. This suggests that with different genetic backgrounds, gender associated immune responses are differentially regulated by microbiota. The net result was the same, since both mouse strains showed similar gender induced differences in immune cell populations in the mesenteric lymph nodes. Therefore, host-microbe interactions might be more complicated than assumed, as bacterial-species adaptations might be highly dependent on the genetic make-up of the individual.
Sex and strain dependent differences in mucosal immunology and microbiota composition in mice.
Sex, Specimen part
View SamplesA dysbiosis in the intestinal microbiome plays a role in the pathogenesis of several immunological diseases. These diseases often show a gender bias, suggesting gender differences in immune responses and in the intestinal microbiome. We hypothesized that gender differences in immune responses are associated with gender differences in microbiota. We demonstrated mouse strain dependent gender differences in the intestinal microbiome. Interestingly, a cluster of colonic genes (related to humoral and cell-mediated immune responses) correlated oppositely with microbiota species abundant in B6 females and in BALB/c males. This suggests that with different genetic backgrounds, gender associated immune responses are differentially regulated by microbiota. The net result was the same, since both mouse strains showed similar gender induced differences in immune cell populations in the mesenteric lymph nodes. Therefore, host-microbe interactions might be more complicated than assumed, as bacterial-species adaptations might be highly dependent on the genetic make-up of the individual.
Sex and strain dependent differences in mucosal immunology and microbiota composition in mice.
Sex, Specimen part
View SamplesPsoriasis is a chronic inflammatory skin disease characterized by marked proliferation of keratinocytes leading to pronounced epidermal hyperplasia, elongation of rete ridges and hyperkeratosis. The most common form of psoriasis, chronic plaque psoriasis (Psoriasis vulgaris), involves relatively stable occurrence and progression of sharply demarcated lesions, usually on the trunk and extremities, which share a combination of trademark histological features, including tortuous and dilated dermal capillaries, loss of the epidermal granular layer, and accumulation of neutrophils beneath parakeratotic scale. In this study, whole-genome transcriptional profiling was used to characterize gene expression in 4 lesional and uninvolved skin samples obtained from patients with stable chronic plaque psoriasis.Skin mRNA expression was analysed by microarray.
Heterogeneity of inflammatory and cytokine networks in chronic plaque psoriasis.
Specimen part, Subject
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