Despite great advances in understanding the mechanisms underlying blood production, lineage specification at the level of multipotent progenitors (MPPs) remains poorly understood. Here, we show that ...MPP2 and MPP3 are distinct myeloid-biased MPP subsets that work together with lymphoid-primed MPP4 cells to control blood production. We find that all MPPs are produced in parallel by hematopoietic stem cells (HSCs), but with different kinetics and at variable levels depending on hematopoietic demands. We also show that the normally rare myeloid-biased MPPs are transiently overproduced by HSCs in regenerating conditions, hence supporting myeloid amplification to rebuild the hematopoietic system. This shift is accompanied by a reduction in self-renewal activity in regenerating HSCs and reprogramming of MPP4 fate toward the myeloid lineage. Our results support a dynamic model of blood development in which HSCs convey lineage specification through independent production of distinct lineage-biased MPP subsets that, in turn, support lineage expansion and differentiation.
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•Blood production is mediated by functionally distinct lineage-biased MPPs•MPP subsets are independently produced by HSCs•Myeloid-biased MPPs serve as a potent source of myeloid amplification•Regeneration occurs at the expense of HSC engraftment and self-renewal activity
Pietras et al. show that HSCs produce functionally distinct lineage-biased MPPs that work together to adapt blood production to hematopoietic demands. Two rare subsets of myeloid-biased MPPs are important for maintaining blood homeostasis at steady state and serve as a potent source of myeloid amplification in regenerative conditions.
Heterogeneity within the self-renewal durability of adult hematopoietic stem cells (HSCs) challenges our understanding of the molecular framework underlying HSC function. Gene expression studies have ...been hampered by the presence of multiple HSC subtypes and contaminating non-HSCs in bulk HSC populations. To gain deeper insight into the gene expression program of murine HSCs, we combined single-cell functional assays with flow cytometric index sorting and single-cell gene expression assays. Through bioinformatic integration of these datasets, we designed an unbiased sorting strategy that separates non-HSCs away from HSCs, and single-cell transplantation experiments using the enriched population were combined with RNA-seq data to identify key molecules that associate with long-term durable self-renewal, producing a single-cell molecular dataset that is linked to functional stem cell activity. Finally, we demonstrated the broader applicability of this approach for linking key molecules with defined cellular functions in another stem cell system.
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•Comparing HSCs purified with four methods identifies key functional molecules•Index sorting links single-cell RNA-seq with single-cell transplantation•EPCRhiCD48−CD150+Scahi purifies HSCs with durable self-renewal•Single-cell biology links mammalian stem cell function with markers and pathways
Wilson et al. combine single-cell functional assays with flow cytometric index sorting and single-cell gene expression assays to reveal gene expression programs of HSCs with durable self-renewal potential in transplantation assays. They also demonstrate the broader applicability of this approach for linking key molecules with defined stem cell functions.
Hematopoietic stem cells (HSCs) develop from the hemogenic endothelium in cluster structures that protrude into the embryonic aortic lumen. Although much is known about the molecular characteristics ...of the developing hematopoietic cells, we lack a complete understanding of their origin and the three‐dimensional organization of the niche. Here, we use advanced live imaging techniques of organotypic slice cultures, clonal analysis, and mathematical modeling to show the two‐step process of intra‐aortic hematopoietic cluster (IACH) formation. First, a hemogenic progenitor buds up from the endothelium and undergoes division forming the monoclonal core of the IAHC. Next, surrounding hemogenic cells are recruited into the IAHC, increasing their size and heterogeneity. We identified the Notch ligand Dll4 as a negative regulator of the recruitment phase of IAHC. Blocking of Dll4 promotes the entrance of new hemogenic Gfi1+ cells into the IAHC and increases the number of cells that acquire HSC activity. Mathematical modeling based on our data provides estimation of the cluster lifetime and the average recruitment time of hemogenic cells to the cluster under physiologic and Dll4‐inhibited conditions.
Synopsis
In this study, combined in vivo imaging, clonal analyses and modeling reveal that formation of embryonic hematopoietic cell clusters from the mouse aortic endothelium is a sequential process, which involves Notch signaling‐dependent integration of hemogenic cells.
Nascent E10.5 aortic cell clusters are proliferative and monoclonal.
Advanced hematopoietic cell clusters become polyclonal via recruitment of neighboring endothelial cells.
Expression of Notch ligand Dll4 is increased in nascent hematopoietic cell clusters.
Blockage of Dll4 in vivo results in perturbed Notch signaling, precocious cluster increase and compromised progression to blood stem cells.
Specification of hematopoietic fate and intra‐aortic cell clusters in the mouse embryo is controlled by Dll4.
Cellular decision-making is mediated by a complex interplay of external stimuli with the intracellular environment, in particular transcription factor regulatory networks. Here we have determined the ...expression of a network of 18 key haematopoietic transcription factors in 597 single primary blood stem and progenitor cells isolated from mouse bone marrow. We demonstrate that different stem/progenitor populations are characterized by distinctive transcription factor expression states, and through comprehensive bioinformatic analysis reveal positively and negatively correlated transcription factor pairings, including previously unrecognized relationships between Gata2, Gfi1 and Gfi1b. Validation using transcriptional and transgenic assays confirmed direct regulatory interactions consistent with a regulatory triad in immature blood stem cells, where Gata2 may function to modulate cross-inhibition between Gfi1 and Gfi1b. Single-cell expression profiling therefore identifies network states and allows reconstruction of network hierarchies involved in controlling stem cell fate choices, and provides a blueprint for studying both normal development and human disease.
Lachryphagous males of Phortica variegata (Fallén, 1823) are gaining increasing attention in Europe, as they act as vectors of the nematode Thelazia callipaeda Railliet & Henry, 1910, causal agent of ...thelaziosis, an emergent zoonotic disease. Currently, there are no effective control strategies against the vector, and surveillance and monitoring rely on time-consuming and nonselective sampling methods. Our aim was to improve the knowledge about the population dynamics and the chemical ecology of the species. A total of 5,726 P. variegata flies (96.4% males and 3.6% females, mostly gravid) were collected in field experiments during June–September of 2020 in an oak forest in northern Spain. Our results indicate that 1) by means of sweep netting a significantly higher number of captures were found both around the collector's body and in the air than at ground level; 2) a positive relationship was detected between the abundance of Phortica flies and temperature, with two significant peaks of abundance at 24 and 33°C; 3) the blend of red wine and cider vinegar was the most attractive bait; 4) yellow traps captured fewer flies compared to black and transparent traps; and 5) a significant reduction toward vinegar and wine was detected in presence of the phenolic monoterpenoid carvacrol. In addition, all the males (n = 690) analyzed by both molecular detection and dissection resulted negative for the presence of T. callipaeda larvae. Overall, these findings provide a better understanding of the vector in terms of monitoring and management strategies.
This research aims to analyse the factors that affect the level of commitment to Corporate Social Responsibility (CSR) of marine tourism companies and restaurants. This commitment can be conditioned ...by economic reasons, stakeholder pressure, difficulties in implementing socio-environmentally responsible actions, and adaptation to change, as reflected in the innovative activities of companies, as well as by the degree of collaboration with public and private agents. This study was carried out on the island of Fuerteventura. A Likert scale questionnaire with 39 items was designed to collect the data, which was processed using a combination of factor analysis and multiple regression analysis. The results show that innovation, stakeholder pressure, and economic reasons have positive effects on companies' commitment to CSR, while poor collaboration with public and private actors and implementation difficulties have negative effects. Given that this sector is highly regulated and depends on different public authorities to carry out its activity, collaboration with the public administration must be improved to reduce barriers for companies and their activities. Moreover, when an island's economy depends almost exclusively on tourist activity, it is essential to develop responsible tourism. This requires public authorities that organise and promote sustainable uses of the territory, while encouraging dialogue and facilitating mechanisms for private initiatives, as well as socio-environmentally responsible companies.
To investigate the relationship between pain extent, as a clinical sign of central sensitization, and clinical, psychological, and pressure sensitivity in women with fibromyalgia syndrome (FMS).
In ...this study, 126 females with FMS completed demographic (age, gender, body mass index, height, weight), clinical (pain history, and pain intensity at rest and during daily living activities), psychological (depression and anxiety levels), and neurophysiological pressure pain threshold (PPT) assessments. The Central Sensitization Inventory (CSI) was also used to collect self-reported symptoms of sensitization. Pain extent and frequency maps were obtained from pain drawings using customized software. After conducting a multivariable correlation analysis to determine the relationships between variables, a stepwise linear regression model analysis was performed to identify variables associated with pain extent.
Pain extent was positively associated with age (r = 0.17), years with pain (r = 0.27), pain during daily life activities (r = 0.27), and CSI (r = 0.42) (all p < 0.05). The stepwise regression analysis revealed that 27.8% of the pain extent was explained by CSI, age, and years with pain.
This study found that larger pain extent was associated with self-reported outcomes, i.e. CSI, but not neurophysiological outcomes, i.e. PPTs, of sensitization in women with FMS. Older age and a longer history with pain symptoms were also associated with larger pain extent.
The objective of this work is to analyze the possibility of compliance with the objectives committed to by the Canary Islands authorities, which aim to reach a completely decarbonized economy by ...2040, meaning ten years earlier than the entire EU. Since historically, energy planning in the Canary Islands did not achieve its objectives by far, we will first identify the historical obstacles which had prevented the achievement of this planification, to later highlight the main differences between the energy transition foreseen by the current planning instruments of the government of the Canary Islands and the expected evolution of the energy transition of the archipelago. Beyond this point, and, within the frame of energy governance, we will understand how the root of this failure lies in planning instruments developed hierarchically, without including the view of the different stakeholders involved in the process. The final goal, after identifying the main barriers faced by the energy transition in the Canary Islands, is to provide a set of recommendations contributing to supporting a successful energy transition for the archipelago.
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•Two physicochemical properties for studying the stability and structure of agricultural soil was proposed.•We study the effect of natural organic matter in the adsorption of ...commercial humic acids.•Two methods we used to analyze the soil: surface free energy and zeta potential.•The obtained results confirm the mordant character of natural organic matter in native soil.
Here we present results of our study about the effect of natural organic matter in the adsorptions processes of commercial humic acid (HA) on the physicochemical properties, stability, and structure of an agricultural olive soil. Our soil belongs to the loamy texture class and gives a medium-low chemical fertility. Its organic carbon content is very low (0.40%), which could be explained by the Mediterranean climate type in which the soil developed. From the fine earth mineralogy, we conclude that smectite was the most abundant mineral in our soil.
We first demonstrated that HA effectively adsorbs onto soil, mainly at basic pH. Electrophoresis measurements of soil particle suspensions as a function of pH in the presence and absence of humic acid clearly demonstrate the adsorption of negatively charged entities onto smectite in the soil. This effect is more significant when the soil contains natural organic matter, which confirms the mordant character of this matter in native soil.
Analysis of surface free energy components leads to the conclusion that humic acid molecules impart a significant electron donor character to the soil particles, which in turn decreases their hydrophilicity. All collected data were used to interpret the final soil structure. Our results are consistent with fabric images obtained by scanning electron microscopy of natural samples that present the major aggregation state. Interpretation of these results can be explained by a combination of electrical and thermodynamic interaction, electrostatic forces, double-layer repulsion, van der Waals attraction, and hydrophilic/hydrophobic repulsion/attraction.
Chimeric antigen receptor (CAR) T-cell adoptive therapy is set to transform the treatment of a rapidly expanding range of malignancies. Although the activation process of normal T cells is well ...characterized, comparatively little is known about the activation of cells via the CAR. Here we have used flow cytometry together with single-cell transcriptome profiling to characterize the starting material (peripheral blood mononuclear cells) and CAR therapeutic products of 3 healthy donors in the presence and absence of antigen-specific stimulation. Analysis of 53,191 single-cell transcriptomes showed APRIL-based CAR products to contain several subpopulations of cells, with cellular composition reproducible from donor to donor, and all major cellular subsets compatible with CAR expression. Only 50% of CAR-expressing cells displayed transcriptional changes upon CAR-specific antigen exposure. The resulting molecular signature for CAR T-cell activation provides a rich resource for future dissection of underlying mechanisms. Targeted data interrogation also revealed that a small proportion of antigen-responding CAR-expressing cells displayed an exhaustion signature, with both known markers and genes not previously associated with T-cell exhaustion. Comprehensive single-cell transcriptomic analysis thus represents a powerful way to guide the assessment and optimization of clinical-grade CAR-T-cells, and inform future research into the underlying molecular processes.
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