Critically ill intensive care unit (ICU) patients commonly develop severe muscle wasting and impaired muscle function, leading to delayed recovery, with subsequent increased morbidity and financial costs, and decrease quality of life of survivors. Acute Quadriplegic Myopathy (AQM) is one of the most common neuromuscular disorders associated with ICU-acquired muscle weakness. Although there are no available treatments for the ICU-acquired muscle weakness, it has been demonstrated that early mobilization can improve its prognosis and functional outcomes. This study aims at improving our understanding of the effects of passive mechanical loading on skeletal muscle structure and function by using a unique experimental rat ICU model allowing analyses of the temporal sequence of changes in mechanically ventilated and pharmacologically paralyzed animals at durations varying from 6 h to 14 days. Results show that passive mechanical loading alleviated the muscle wasting and the loss of force-generation associated with the ICU intervention, resulting in a doubling of the functional capacity of the loaded vs. unloaded muscles after a 2-week ICU intervention. We demonstrated that the improved maintenance of muscle structure and function is likely a consequence of a reduced oxidative stress, and a reduced loss of the molecular motor protein myosin. A complex temporal gene expression pattern, delineated by microarray analysis, was observed with loading-induced changes in transcript levels of sarcomeric proteins, muscle developmental processes, stress response, ECM/cell adhesion proteins and metabolism. Thus, the results from this study show that passive mechanical loading alleviates the severe negative consequences on muscle structure and function associated with mechanical silencing in ICU patients, strongly supporting early and intense physical therapy in immobilized ICU patients.
Sparing of muscle mass and function by passive loading in an experimental intensive care unit model.
Sex, Specimen part, Time
View SamplesCTLA-4 is thought to inhibit effector T cells both intrinsically, by competing with CD28 for B7 ligands, and extrinsically, through the action of regulatory T cells. We studied in vivo responses of normal and CTLA-4-deficient antigen-specific murine effector CD4+ T cells. In order to do these studies in a physiological model of immunity to foreign antigen, we transferred small numbers of congenically marked RAG2-deficient 5C.C7 T cells with either a normal or knockout allele of CTLA-4 into normal syngeneic B10.A recipient mice. The T cells were then activated by immunization with MCC peptide and LPS. To look for transcriptional signatures of negative regulation of T cell responses by CTLA-4, we used microarray analysis to compare transcripts in wild type and CTLA-4 KO 5C.C7 T cells four days after immunization. This is the first instance in which differences are observed in extent of accumulation of wild type and CTLA-4 KO 5C.C7 T cells.
Cutting edge: CTLA-4 on effector T cells inhibits in trans.
Specimen part
View SamplesA LHX4 transgenic reporter line with high specificity for developing mouse cone photoreceptors was identified and used to purify early stage cone photoreceptors for profiling by single cell RNA sequencing. Overall design: Collection of FACS-sorted LHX4::GFP+ E14.5 early cones and LHX4::GFP- retinal cells for further analysis.
Identification of Genes With Enriched Expression in Early Developing Mouse Cone Photoreceptors.
Specimen part, Cell line, Subject
View SamplesAnalysis of knockdown of SDHD with or without knockdown of CDKN1C or SLC22A18 at gene expression level.
Parent-of-origin tumourigenesis is mediated by an essential imprinted modifier in SDHD-linked paragangliomas: SLC22A18 and CDKN1C are candidate tumour modifiers.
Specimen part, Cell line
View SamplesDominant RUNX1 inhibition has been proposed as a common pathway for CBF-leukemia. CBFb-SMMHC, a fusion protein in human acute myeloid leukemia (AML), dominantly inhibits RUNX1 largely through its RUNX1 high-affinity binding domain (HABD). We generated knock-in mice expressing CBFb-SMMHC with a HABD deletion, CBFb-SMMHCd179-221. These mice developed leukemia highly efficiently, even though hematopoietic defects associated with Runx1-inhibition were partially rescued.
Accelerated leukemogenesis by truncated CBF beta-SMMHC defective in high-affinity binding with RUNX1.
Specimen part
View SamplesCure rates for patients with acute myeloid leukemia (AML) remain low despite ever-increasing dose intensity of cytotoxic therapy. In an effort to identify novel approaches to AML therapy, we recently reported a new method of chemical screening based on the modulation of a gene expression signature of interest. We applied this approach to the discovery of AML-differentiation-promoting compounds. Among the compounds inducing neutrophilic differentiation was DAPH1 (4,5-dianilinophthalimide), previously reported to inhibit epidermal growth factor receptor (EGFR) kinase activity. Here we report that the Food and Drug Administration (FDA)-approved EGFR inhibitor gefitinib similarly promotes the differentiation of AML cell lines and primary patient-derived AML blasts in vitro. Gefitinib induced differentiation based on morphologic assessment, nitro-blue tetrazolium reduction, cell-surface markers, genome-wide patterns of gene expression, and inhibition of proliferation at clinically achievable doses. Importantly, EGFR expression was not detected in AML cells, indicating that gefitinib functions through a previously unrecognized EGFR-independent mechanism. These studies indicate that clinical trials testing the efficacy of gefitinib in patients with AML are warranted.
Gefitinib induces myeloid differentiation of acute myeloid leukemia.
Disease, Disease stage, Cell line
View SamplesVarious mesenchymal cell types have been identified as critical components of the hematopoietic stem/progenitor cell (HSPC) niche. Although several groups have described the generation of mesenchyme from human pluripotent stem cells (hPSC), the capacity of such cells to support hematopoiesis has not been reported. Here we have demonstrated that distinct mesenchymal subpopulations co-emerge from mesoderm during hPSC differentiation. Despite co-expression of common mesenchymal markers (CD73, CD105, CD90, PDGFRß), a subset of cells defined as CD146++CD140alow supported functional HSPC ex vivo while CD146-CD140a+ cells drove differentiation. The CD146++ subset expressed genes associated with the HSPC niche and high levels of the Wnt inhibitors. HSPC support was contact-dependent and was mediated in part through JAG1 expression. Molecular profiling revealed remarkable transcriptional similarity between hPSC-derived CD146++ and primary human CD146++ perivascular cells. The derivation of diverse pools of mesenchymal populations from hPSC opens potential avenues to model their developmental and functional differences and to improve cell-based therapeutics from hPSC. Overall design: Our goal was to analyze and compare transcriptome of human pluripoten stem cell-derived mesenchyme (CD146++ and CD146-) with primary human lipoaspirate tissue-derived pericyte (CD146+) and CD146- mesenchymal populations.
Transcriptionally and Functionally Distinct Mesenchymal Subpopulations Are Generated from Human Pluripotent Stem Cells.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Esrrb extinction triggers dismantling of naïve pluripotency and marks commitment to differentiation.
Specimen part, Cell line
View SamplesWe used microarrays to determine how the quality and quantity of peptide-MHC impact TCR-induced gene expression in vivo.
Distinct influences of peptide-MHC quality and quantity on in vivo T-cell responses.
No sample metadata fields
View SamplesSelf-renewal of embryonic stem cells (ESCs) cultured in serum-LIF is incomplete with some cells initiating differentiation. While this is reflected in heterogeneous expression of naive pluripotency transcription factors (TFs), the link between TF heterogeneity and differentiation is not fully understood. Here we purify ESCs with distinct TF expression levels from serum-LIF cultures to uncover early events during commitment from nave pluripotency. ESCs carrying fluorescent Nanog and Esrrb reporters show Esrrb downregulation only in NANOGlow cells. Independent Esrrb reporter lines demonstrate that ESRRBnegative ESCs cannot effectively self-renew. Upon ESRRB loss, pre-implantation pluripotency gene expression collapses. ChIP-Seq identifies different regulatory element classes that bind both OCT4 and NANOG in ESRRBhigh cells. Class I elements lose NANOG and OCT4 binding in ESRRBnegative ESCs and associate with genes expressed preferentially in nave ESCs. In contrast, class II elements retain OCT4 but not NANOG binding in ESRRBnegative cells and associate with more broadly expressed genes. Therefore, mechanistic differences in TF function act cumulatively to restrict potency during exit from nave pluripotency.
Esrrb extinction triggers dismantling of naïve pluripotency and marks commitment to differentiation.
Specimen part
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