Hematopoietic stem cells (HSCs) balance self-renewal and differentiation to maintain homeostasis. With aging, the frequency of polar HSCs decreases. Cell polarity in HSCs is controlled by the activity of the small RhoGTPase Cdc42. Here we demonstrate, using a comprehensive set of paired daughter cell analyses that include single cell 3D-confocal imaging, single cell transplants, single cell RNA-seq as well as single cell ATAC-seq, that the outcome of HSC divisions is strongly linked to the polarity status before mitosis, which is in turn determined by the level of the activity Cdc42 in stem cells. Aged apolar HSCs undergo preferentially self-renewing symmetric divisions, resulting in daughter stem cells with reduced regenerative capacity and lymphoid potential, while young polar HSCs undergo preferentially asymmetric divisions. Mathematical modeling in combination with experimental data implies a mechanistic role of the asymmetric sorting of Cdc42 in determining the potential of daughter cells via epigenetic mechanisms. Therefore, molecules that control HSC polarity might serve as modulators of the mode of stem cell division regulating the potential of daughter cells. Overall design: Sorted single cells were cultured with and without treatment in the presence of cytokines until first cell division (40-44hrs). The daughter cells were manually separated, washed with PBS and collected for RNA sequencing.
Aging alters the epigenetic asymmetry of HSC division.
Specimen part, Cell line, Treatment, Subject
View SamplesMicroarray expression analysis of mouse ESCs treated with the MYCi 10058-F4.
Myc Depletion Induces a Pluripotent Dormant State Mimicking Diapause.
Specimen part
View SamplesIdentification of the role of retinoic acid on the activation of the dHSCs
Vitamin A-Retinoic Acid Signaling Regulates Hematopoietic Stem Cell Dormancy.
Specimen part
View SamplesThe pesticide rotenone, a neurotoxin that inhibits the mitochondrial complex I, and destabilizes microtubules (MT) has been linked to Parkinson disease (PD) etiology and is often used to model this neurodegenerative disease (ND). Many of the mechanisms of action of rotenone are posited mechanisms of neurodegeneration; however, they are not fully understood. Therefore, the study of rotenone-affected functional pathways is pertinent to the understanding of NDs pathogenesis. This report describes the transcriptome analysis of a neuroblastoma (NB) cell line chronically exposed to marginally toxic and moderately toxic doses of rotenone. The results revealed a complex pleiotropic response to rotenone that impacts a variety of cellular events, including cell cycle, DNA damage response, proliferation, differentiation, senescence and cell death, which could lead to survival or neurodegeneration depending on the dose and time of exposure and cell phenotype. The response encompasses an array of physiological pathways, modulated by transcriptional and epigenetic regulatory networks, likely activated by homeostatic alterations. Pathways that incorporate the contribution of MT destabilization to rotenone toxicity are suggested to explain complex I-independent rotenone-induced alterations of metabolism and redox homeostasis. The postulated mechanisms involve the blockage of mitochondrial voltage-dependent anions channels (VDACs) by tubulin, which coupled with other rotenone-induced organelle dysfunctions may underlie many presumed neurodegeneration mechanisms associated with pathophysiological aspects of various NDs including PD, AD and their variant forms. Thus, further investigation of such pathways may help identify novel therapeutic paths for these NDs.
Transcriptome analysis of a rotenone model of parkinsonism reveals complex I-tied and -untied toxicity mechanisms common to neurodegenerative diseases.
Cell line, Treatment, Time
View SamplesAlpha synuclein (SNCA) has been linked to neurodegenerative diseases (synucleinopathies) that include Parkinsons disease (PD). Although the primary neurodegeneration in PD involves nigrostriatal dopaminergic neurons, more extensive yet regionally selective neurodegeneration is observed in other synucleinopathies. Furthermore, SNCA is ubiquitously expressed in neurons and numerous neuronal systems are dysfunctional in PD. Therefore it is of interest to understand how overexpression of SNCA affects neuronal function in regions not directly targeted for neurodegeneration in PD. To gain a better understanding of the consequences of excessive SNCA expression on basal ganglia function, we performed transcriptome analysis of striatal tissue from male Thy1-aSyn-mice and wt littermates. The present study investigated the consequences of SNCA overexpression on cellular processes and functions in the striatum of mice overexpressing wild-type, human SNCA under the Thy1 promoter (Thy1-aSyn mice) by transcriptome analysis. The analysis revealed alterations in multiple biological processes in the striatum of Thy1-aSyn mice, including synaptic plasticity, signaling, transcription, apoptosis, and neurogenesis.
Analysis of striatal transcriptome in mice overexpressing human wild-type alpha-synuclein supports synaptic dysfunction and suggests mechanisms of neuroprotection for striatal neurons.
Sex, Age, Specimen part
View SamplesOne clear hallmark of mammalian promoters is the presence of CpG islands (CGIs) at more than two thirds of genes whereas TATA boxes are only present at a minority of promoters. Using genome-wide approaches, we show that GC content and CGIs are major promoter elements in mammalian cells, able to govern open chromatin conformation and support paused transcription. First, we define three classes of promoters with distinct transcriptional directionality and pausing properties which correlate with their GC content. We further analyze the direct influence of GC content on nucleosome positioning and depletion, and show that CGIs correlate with nucleosome depletion both in vivo and in vitro. We also show that transcription is not essential for nucleosome exclusion but influences both a weak +1 and a well-positioned nucleosome at CGI borders. Altogether our data support the idea that CGIs have become an essential feature of promoter structure defining novel regulatory properties in mammals. Overall design: Nucleosome density and positioning were studied by high-throughput sequencing of DNA previously treated with Mnase. In parallel, chIPseq for PolII and H3K27ac were performed in mouse and human with different conditions to assess a potential effect of transcription on nucleosomes properties. To investigate transcription at promoters, we analyzed together with genome-wide Pol II accumulation by ChIP-Seq, paused bidirectional transcripts associated with transcription start sites (TSS RNAs).
CpG islands and GC content dictate nucleosome depletion in a transcription-independent manner at mammalian promoters.
Specimen part, Cell line, Subject
View SamplesMurine Cytomegalovirus (MCMV) infection leads to the activation of various immune cells, including dendritic cells (DCs) and Natural Killer (NK) cells. This activation is partly driven by innate cytokines including IFN-I, which are induced early after infection. The objective was to address the role of different innate cytokines in shaping DC subsets and NK cell responses, in particular the role of cell intrinsic responses to IFN-I.
Differential responses of immune cells to type I interferon contribute to host resistance to viral infection.
Specimen part
View SamplesDendritic cells (DCs) are a complex group of cells which play a critical role in vertebrate immunity. They are subdivided into conventional DC (cDC) subsets (CD11b and CD8alpha in mouse) and plasmacytoid DCs (pDCs). Natural killer cells are innate lymphocytes involved in the recognition and killing of abnormal self cells, including virally infected cells or tumor cells. DCs and NK cells are activated very early upon viral infections and regulate one another. However, the global responses of DC and NK cells early after viral infection in vivo and their molecular regulation are not entirely characterized. The goal of this experiment was to use global gene expression profiling to assess the global genetic reprogramming of DC and NK cells during a viral infection in vivo, as compared to B lymphocytes, and to investigate the underlying molecular mechanisms
Differential responses of immune cells to type I interferon contribute to host resistance to viral infection.
Sex, Specimen part
View SamplesThe injection of the pathogen-associated molecular pattern Polyinosinic-polycytidylic acid (poly(I:C)) leads to the activation of various immune cells, including dendritic cells (DCs) and Natural Killer (NK) cells. This activation is due to different innate cytokines produced early after injection, in particular IFN-I. The objective of the study was to compare the pattern of expression of IFN-I stimulated genes between DC and NK cells.
Differential responses of immune cells to type I interferon contribute to host resistance to viral infection.
Specimen part
View SamplesTissue repair is a subset of a broad repertoire of IL-4/IL-13-dependent host responses during helminth infections. Here, we show that IL-4/IL-13 alone were not sufficient, but IL-4/IL-13 together with apoptotic cells induced the tissue repair program in macrophages. Genetic ablation of sensors of apoptotic cells impaired the proliferation of tissue-resident macrophages and induction of anti-inflammatory/tissue repair genes in the lung following helminth infection or the damage caused by induction of colitis in the gut. In contrast, recognition of apoptotic cells was dispensable for cytokine-dependent induction of pattern recognition receptor, cell adhesion or chemotaxis genes in macrophages. Detection of apoptotic cells can therefore spatially compartmentalize or prevent premature or ectopic activity of pleiotropic, soluble cytokines, such as IL-4/IL-13. Overall design: RNA sequencing of lung resident macrophages from WT and Axl-/-Mertk-/- mice upon infection with N. brasiliensis
Macrophage function in tissue repair and remodeling requires IL-4 or IL-13 with apoptotic cells.
Age, Specimen part, Cell line, Subject
View Samples