Differential Expression of Novel Potential Regulators in Hematopoietic Stem Cells

The hematopoietic system is an invaluable model both for understanding basic developmental biology and for developing clinically relevant cell therapies. Using highly purified cells and rigorous microarray analysis we have compared the expression pattern of three of the most primitive hematopoietic subpopulations in adult mouse bone marrow: long-term hematopoietic stem cells (HSC), short-term HSC, and multipotent progenitors. All three populations are capable of differentiating into a spectrum of mature blood cells, but differ in their self-renewal and proliferative capacity. We identified numerous novel potential regulators of HSC self-renewal and proliferation that were differentially expressed between these closely related cell populations. Many of the differentially expressed transcripts fit into pathways and protein complexes not previously identified in HSC, providing evidence for new HSC regulatory units. Extending these observations to the protein level, we demonstrate expression of several of the corresponding proteins, which provide novel surface markers for HSC. We discuss the implications of our findings for HSC biology. In particular, our data suggest that cell–cell and cell–matrix interactions are major regulators of long-term HSC, and that HSC themselves play important roles in regulating their immediate microenvironment

Molecular Signatures of Quiescent, Mobilized and Leukemia-Initiating Hematopoietic Stem Cells

Hematopoietic stem cells (HSC) are rare, multipotent cells capable of generating all specialized cells of the blood system. Appropriate regulation of HSC quiescence is thought to be crucial to maintain their lifelong function; however, the molecular pathways controlling stem cell quiescence remain poorly characterized. Likewise, the molecular events driving leukemogenesis remain elusive. In this study, we compare the gene expression profiles of steady-state bone marrow HSC to non-self-renewing multipotent progenitors; to HSC treated with mobilizing drugs that expand the HSC pool and induce egress from the marrow; and to leukemic HSC in a mouse model of chronic myelogenous leukemia. By intersecting the resulting lists of differentially regulated genes we identify a subset of molecules that are downregulated in all three circumstances, and thus may be particularly important for the maintenance and function of normal, quiescent HSC. These results identify potential key regulators of HSC and give insights into the clinically important processes of HSC mobilization for transplantation and leukemic development from cancer stem cells

Abordaxe fisioterápico no asma infantil

[Resumen] Objetivo: analizar qué intervenciones se están llevando a cabo por parte de la fisioterapia en la patología del asma. Material y métodos: revisión de artículos en los cuales se lleven a cabo intervenciones de fisioterapia en niños asmáticos. La búsqueda se efectuó en las bases de datos Pubmed, PEDro, Web of Science y Scopus, seleccionando artículos publicados entre 2013 y 2017 en lengua inglesa, portuguesa y española. Resultados: se seleccionaron 6 artículos, la mayoría de calidad intermedia, con variabilidad en el número de sujetos en cada estudio. La población que se seleccionó comprende desde el nacimiento hasta los 18 años. Las terapias fisioterápicas empleadas son variables. Se realiza en todos los casos un tratamiento enfocado al abordaje de las capacidades físicas por medio de diferentes programas de entrenamiento que cada estudio enfocó de forma diferente. Los aspectos más evaluados han sido la función pulmonar, la calidad de vida y la disnea, medidos a través de diferentes test y pruebas funcionales. Se obtienen resultados positivos en el manejo del asma con cada uno de estos programas de entrenamiento físico. Conclusiones: existen múltiples programas de intervención fisioterápica sobre el asma. Se llevan a cabo programas de entrenamiento de la musculatura inspiratoria, entrenamiento aeróbico, anaeróbico, de fuerza y equilibrio por parte de la fisioterapia en el abordaje de esta patología y todos presentan beneficio sobre ella. Asimismo, se objetivó que el programa de tratamiento que engloba un entrenamiento basado en ejercicio aeróbico y ejercicios respiratorios presenta una mayor eficacia.[Abstract] Objective: to analyze what interventions are being carried out by physiotherapy in the pathology of asthma. Material and methods: review of articles in which physiotherapy interventions are carried out in asthmatic children. The search was carried out in the Pubmed, PEDro, Web of Science and Scopus databases, selecting articles published between 2013 and 2017 in English, Portuguese and Spanish. Results: Six articles were selected, most of intermediate quality, with variability in the number of subjects in each study. The population that was selected comprises from birth to 18 years. The physiotherapeutic therapies used are variable. In all cases, a treatment focused on addressing physical abilities is carried out through different training programs that each study focused on differently. The most evaluated aspects have been pulmonary function, quality of life and dyspnea, measured through different tests and functional tests. Positive results are obtained in the management of asthma with each of these physical training programs. Conclusions: There are multiple programs of physiotherapy intervention on asthma. Training programs for inspiratory musculature, aerobic, anaerobic, strength and balance training are carried out by physiotherapy in the approach to this pathology and all have benefit over it. Likewise, it was found that the treatment program that includes a training based on aerobic exercise and breathing exercises is more effective.[Resumo] Obxectivo: analizar que intervencións se están a facer por parte da fisioterapia na patoloxía da asma. Material e metodoloxía: revisión de artículos nos que se fagan intervencións de fisioterapia en nenos asmáticos. A búsqueda efectuouse nas bases de datos Pubmed, PEDro, Web of Science y Scopus, seleccionando artículos publicados entre 2013 y 2017 en lingua inglesa, portuguesa e española. Resultados: seleccionáronse 6 artigos, a maioría de calidade intermedia, con variabilidade no número de suxeitos en cada estudo. A poboación que se seleccionou comprende dende o nacemento ata os 18 anos. As terapias fisioterápicas empregadas son variables. Realizouse en todos os casos un tratamento enfocado á abordaxe das capacidades físicas por medio de diferentes programas de entrenamento que cada estudo enfocou de forma diferente. Os aspectos máis avaliados foron a función pulmonar, a calidade da vida e a disnea, medidos a través de diferentes test e probas funcionais. Obtéñense resultados positivos no manexo do asma con cada un destes programas de entrenamento físico. Conclusións: existen múltiples programas de intervención fisioterápica sobre a asma infantil. Lévanse a cabo programas de entrenamento da musculatura inspiratoria, entrenamiento aeróbico, anaeróbico, de forza e equilibrio por parte da fisioterapia no abordaxe desta patoloxía e todos presentan beneficio sobre ela. Así mesmo obxectivouse que o programa de tratamento que engloba un entrenamento baseado no exercicio aeróbico e exercicios respiratorios presenta unha maior eficacia.Traballo fin de grao (UDC.FCS). Fisioterapia. Curso 2017/201

Computational Integration of Homolog and Pathway Gene Module Expression Reveals General Stemness Signatures

The stemness hypothesis states that all stem cells use common mechanisms to regulate self-renewal and multi-lineage potential. However, gene expression meta-analyses at the single gene level have failed to identify a significant number of genes selectively expressed by a broad range of stem cell types. We hypothesized that stemness may be regulated by modules of homologs. While the expression of any single gene within a module may vary from one stem cell type to the next, it is possible that the expression of the module as a whole is required so that the expression of different, yet functionally-synonymous, homologs is needed in different stem cells. Thus, we developed a computational method to test for stem cell-specific gene expression patterns from a comprehensive collection of 49 murine datasets covering 12 different stem cell types. We identified 40 individual genes and 224 stemness modules with reproducible and specific up-regulation across multiple stem cell types. The stemness modules included families regulating chromatin remodeling, DNA repair, and Wnt signaling. Strikingly, the majority of modules represent evolutionarily related homologs. Moreover, a score based on the discovered modules could accurately distinguish stem cell-like populations from other cell types in both normal and cancer tissues. This scoring system revealed that both mouse and human metastatic populations exhibit higher stemness indices than non-metastatic populations, providing further evidence for a stem cell-driven component underlying the transformation to metastatic disease

Clearing the Haze: How Does Nicotine Affect Hematopoiesis before and after Birth?

Hematopoiesis is a tightly regulated process orchestrated by cell-intrinsic and cell-extrinsic cues. Over the past several decades, much effort has been focused on understanding how these cues regulate hematopoietic stem cell (HSC) function. Many endogenous key regulators of hematopoiesis have been identified and extensively characterized. Less is known about the mechanisms of long-term effects of environmental toxic compounds on hematopoietic stem and progenitor cells (HSPCs) and their mature immune cell progeny. Research over the past several decades has demonstrated that tobacco products are extremely toxic and pose huge risks to human health by causing diseases like cancer, respiratory illnesses, strokes, and more. Recently, electronic cigarettes have been promoted as a safer alternative to traditional tobacco products and have become increasingly popular among younger generations. Nicotine, the highly toxic compound found in many traditional tobacco products, is also found in most electronic cigarettes, calling into question their purported “safety”. Although it is known that nicotine is toxic, the pathophysiology of disease in exposed people remains under investigation. One plausible contributor to altered disease susceptibility is altered hematopoiesis and associated immune dysfunction. In this review, we focus on research that has addressed how HSCs and mature blood cells respond to nicotine, as well as identify remaining questions

From Hematopoietic Stem Cells to Platelets: Unifying Differentiation Pathways Identified by Lineage Tracing Mouse Models

Platelets are the terminal progeny of megakaryocytes, primarily produced in the bone marrow, and play critical roles in blood homeostasis, clotting, and wound healing. Traditionally, megakaryocytes and platelets are thought to arise from multipotent hematopoietic stem cells (HSCs) via multiple discrete progenitor populations with successive, lineage-restricting differentiation steps. However, this view has recently been challenged by studies suggesting that (1) some HSC clones are biased and/or restricted to the platelet lineage, (2) not all platelet generation follows the "canonical" megakaryocytic differentiation path of hematopoiesis, and (3) platelet output is the default program of steady-state hematopoiesis. Here, we specifically investigate the evidence that in vivo lineage tracing studies provide for the route(s) of platelet generation and investigate the involvement of various intermediate progenitor cell populations. We further identify the challenges that need to be overcome that are required to determine the presence, role, and kinetics of these possible alternate pathways

Tn5Prime, a Tn5 based 5' capture method for single cell RNA-seq.

RNA-sequencing (RNA-seq) is a powerful technique to investigate and quantify entire transcriptomes. Recent advances in the field have made it possible to explore the transcriptomes of single cells. However, most widely used RNA-seq protocols fail to provide crucial information regarding transcription start sites. Here we present a protocol, Tn5Prime, that takes advantage of the Tn5 transposase-based Smart-seq2 protocol to create RNA-seq libraries that capture the 5' end of transcripts. The Tn5Prime method dramatically streamlines the 5' capture process and is both cost effective and reliable. By applying Tn5Prime to bulk RNA and single cell samples, we were able to define transcription start sites as well as quantify transcriptomes at high accuracy and reproducibility. Additionally, similar to 3' end-based high-throughput methods like Drop-seq and 10× Genomics Chromium, the 5' capture Tn5Prime method allows the introduction of cellular identifiers during reverse transcription, simplifying the analysis of large numbers of single cells. In contrast to 3' end-based methods, Tn5Prime also enables the assembly of the variable 5' ends of the antibody sequences present in single B-cell data. Therefore, Tn5Prime presents a robust tool for both basic and applied research into the adaptive immune system and beyond