To guarantee blood supply throughout adult life hematopoietic stem cells (HSCs) need to carefully balance between self-renewing cell divisions and quiescence. Identification of genes controlling HSC self-renewal is of utmost importance given that HSCs are the only stem cells with broad clinical applications. Transcription factor PU.1 is one of the major regulators of myeloid and lymphoid development. Recent reports suggest that PU.1 mediates its functions via gradual expression level changes rather than binary on/off states. So far, this has not been considered in any study of HSCs and thus, PU.1s role in HSC function has remained largely unclear. Here we demonstrate using hypomorphic mice with an engineered disruption of an autoregulatory feedback loop that decreased PU.1 levels resulted in loss of key HSC functions, all of which could be fully rescued by restoration of proper PU.1 levels via a human PU.1 transgene. Mechanistically, we found excessive HSC cell divisions and altered expression of cell cycle regulators whose promoter regions were bound by PU.1 in normal HSCs. Adequate PU.1 levels were maintained by a mechanism of direct autoregulation restricted to HSCs through a physical interaction of a -14kb enhancer with the proximal promoter. Our findings identify PU.1 as novel regulator controling the switch between cell division and quiescence in order to prevent exhaustion of HSCs. Given that even moderate level changes greatly impact stem cell function, our data suggest important therapeutic implications for leukemic patients with reduced PU.1 levels. Moreover, we provide first proof, that autoregulation of a transcription factor, PU.1, has a crucial function in vivo. We anticipate that our concept of how autoregulation forms an active chromosomal conformation will impact future research on transcription factor networks regulating stem cell fate.
Sustained PU.1 levels balance cell-cycle regulators to prevent exhaustion of adult hematopoietic stem cells.
Specimen part
View SamplesWe did transcription profiling on the effect of rlm1 (MAPK Slt2 transcription factor) deletion and swi3 (component of SWI/SNF complex involved in chromatin remodeling) deletion in genes involved in cell wall stress (Congo Red) response.
Chromatin remodeling by the SWI/SNF complex is essential for transcription mediated by the yeast cell wall integrity MAPK pathway.
No sample metadata fields
View SamplesTo define the characteristics of human oral mucosa fibroblasts (hOFs), we analyzed the gene expression of hOFs compared with that of human dermal fibroblasts (hDFs), and that of hOF-derived induced pluripotent stem cells (hOF-iPSCs).
Gene Signature of Human Oral Mucosa Fibroblasts: Comparison with Dermal Fibroblasts and Induced Pluripotent Stem Cells.
Sex, Age, Specimen part
View SamplesThe putative trancriptional regulator PA2449 was found to be essential for both glycine/serine metabolism and the production of phenazines in P. aeruignosa PAO1.
Gene PA2449 is essential for glycine metabolism and pyocyanin biosynthesis in Pseudomonas aeruginosa PAO1.
No sample metadata fields
View SamplesThe transcriptome of P. aeruginosa PAO1 in the presence of extracelluar 2-oxoglutarate at a concentration of 20 mM.
Genetic analysis of the assimilation of C5-dicarboxylic acids in Pseudomonas aeruginosa PAO1.
No sample metadata fields
View SamplesTo understand the molecular mechanism underlying inflammatory reaction in vascular system post exposure to ionizing radiation, we carried out microarray analysis in HUVEC exposed with X-ray
Comprehensive and computational analysis of genes in human umbilical vein endothelial cells responsive to X-irradiation.
Specimen part
View SamplesSkeletal muscle mass is an important determinant of whole-body glucose disposal. We here show that mice (M-PDK1KO mice) with skeletal muscle–specific deficiency of 3'-phosphoinositide–dependent kinase 1 (PDK1), a key component of the phosphatidylinositol 3-kinase (PI3K) signaling pathway, manifest a reduced skeletal muscle mass under the static condition as well as impairment of exercise load–induced muscle hypertrophy.
Role of PDK1 in skeletal muscle hypertrophy induced by mechanical load.
Sex, Specimen part
View SamplesWild-type cells were cultured at 30 deg and cells were harvested. Total RNAs were purified from 3 populations.
Mapping of long-range associations throughout the fission yeast genome reveals global genome organization linked to transcriptional regulation.
No sample metadata fields
View SamplesInfliximab (IFX) has been reported as the further therapy in intravenous immunoglobulin G (IVIG)-resistant Kawasaki disease (KD) patients. IFX is a monoclonal antibody that blocks the pro-inflammatory cytokine tumor necrosis factor (TNF)-, but how IFX affect KD vasculitis is unknown. We investigated expression profiling of whole blood cells to elucidate the molecular mechanisms of the effectiveness of IFX therapy and to find characteristic biomarker and an important target in refractory KD. Methods: Refractory KD patients who failed to respond to repeated intravenous immunoglobulin G (IVIG) infusions had received a single infusion of IFX as third therapy. To validate specifically transcripts abundance for IFX therapy, we detected the altered transcripts expression and signaling pathways of whole blood mRNA in these IFX-responsive patients (n=8) using Affymetrix array, comparing initial IVIG-responsive patients (n=6).Results: A total of 1,388 transcripts abundance were significantly altered before and after IFX treatment. These transcripts abundance in IFX had Nucleotide-binding oligomerization domain pathway that play a role in activation of NFB and IL-1 signaling pathway outside the field of TNF- signaling pathway. Fifty transcripts including Peptidase inhibitor-3 (PI3), Matrix metalloproteinase-8 (MMP8), Chemokine (C-C motif) receptor-2 (CCR2) and Pentraxin-3 (PTX3) were significantly down-regulated in IFX. Conclusion: We demonstrated that the inhibition of TNF- by IFX have affected various molecular mechanism materially for IVIG-resistant KD patients.
Transcriptional regulation by infliximab therapy in Kawasaki disease patients with immunoglobulin resistance.
Specimen part, Disease, Disease stage, Treatment, Subject
View SamplesUnlike other members of the MAPK family, ERK5 contains a large C-terminal domain with transcriptional activation capability in addition to an N-terminal canonical kinase domain. Genetic deletion of ERK5 is embryonic lethal and tissue-restricted deletions have profound effects on erythroid development, cardiac function and neurogenesis. In addition, depletion of ERK5 is anti-inflammatory and anti-tumorigenic. Small molecule inhibition of ERK5 has been shown to have promising activity in cell and animal models of inflammation and oncology. Here we report the synthesis and biological characterization of potent, selective ERK5 inhibitors. In contrast to both genetic depletion/deletion of ERK5 and inhibition with previously reported compounds, inhibition of the kinase with the most selective of the new inhibitors had no anti-inflammatory or anti-proliferative activity. The source of efficacy in previously reported ERK5 inhibitors is shown to be off-target activity on bromodomains (BRDs), conserved protein modules involved in recognition of acetyl-lysine residues during transcriptional processes. It is likely that phenotypes reported from genetic deletion or depletion of ERK5 arise from removal of a non-catalytic function of ERK5. The newly reported inhibitors should be useful in determining which of the many reported phenotypes are due to kinase activity, and delineate which can be pharmacologically targeted. Overall design: Two cellular models with reported ERK5-regulated signaling were used: Pam3CSK4-stimulated HUVECs as a model of inflammation, and EGF-stimulated HeLa cells as an established cell model of ERK5 regulation. Cells were pre-incubated with DMSO vehicle, AX15836 (ERK5 inhibitor), AX15839 (dual ERK5/BRD inhibitor), or I-BET762 (BRD inhibitor), then stimulated with agonist. Cellular responses were verified by immunoassays and western blots using replicate wells in the same experiment.
ERK5 kinase activity is dispensable for cellular immune response and proliferation.
Specimen part, Subject, Compound
View Samples