Iron is an essential component of the erythrocyte protein hemoglobin and is crucial to oxygen transport in vertebrates. In the steady state, erythrocyte production is in equilibrium with erythrocyte removal1. In various pathophysiological conditions, erythrocyte life span is severely compromised, which threatens the organism with anemia and iron toxicity 2,3. Here we identify anon-demand mechanism specific to the liver that clears erythrocytes and recycles iron. We showthat Ly-6Chigh monocytes ingest stressed and senescent erythrocytes, accumulate in the liver, and differentiate to ferroportin 1 (FPN1)-expressing macrophages that can deliver iron to hepatocytes. Monocyte-derived FPN1+ Tim-4neg macrophages are transient, reside alongside embryonically-derived Tim-4high Kuppfer cells, and depend on Csf1 and Nrf2. The spleenlikewise recruits iron-loaded Ly-6Chigh monocytes, but they do not differentiate into ironrecycling macrophages due to the suppressive action of Csf2, and are instead shuttled to the livervia coordinated chemotactic cues. Inhibiting this mechanism by preventing monocyte recruitment to the liver leads to kidney failure and liver damage. These observations identify the liver as the primary organ supporting emergency erythrocyte removal and iron recycling, and uncover a mechanism by which the body adapts to fluctuations in erythrocyte integrity.
On-demand erythrocyte disposal and iron recycling requires transient macrophages in the liver.
Specimen part
View SamplesPluripotent stem cells, including human embryonic stem (hES) and induced pluripotent stem (hiPS) cells, have been regarded as useful sources for cell?based transplantation therapy. However immunogenicity of the cells remains the major determinant for successful clinical application. We report the examination of several hES cell lines (NTU1 and H9), hiPS cell lines, and their derivatives (including stem cell?derived hepatocytes) for the expression of major histocompatibility complex (MHC), natural killer (NK) cell receptor (NKp30, NKp44, NKp46) ligand, immune?related genes, human leukocyte antigen (HLA) haplotyping, and the effects in functional mixed lymphocyte reaction (MLR). Flow cytometry showed lower levels (percentages and fluorescence intensities) of MHC class I (MHC?I) molecules, 2?microglobulin and HLA?E in undifferentiated stem cells, but the levels were increased after co?treatment with interferon gamma and/or in vitro differentiation. Antigen presenting cell markers (CD11c, CD80 and CD86) and MHC?II (HLA?DP, DQ and DR) remained low throughout the treatments. Recognitions of stem cells/derivatives by NK lysis receptors were lower or absent. Activation of responder lymphocytes was significantly lower by undifferentiated stem cells than by allogeneic lymphocytes in MLR, but differentiated NTU1 hES cells induced a cell number?dependent lymphocyte proliferation comparable with that by allogeneic lymphocytes. Interestingly activation of lymphocytes by differentiated hiPS cells or H9 cells became blunted at higher cell numbers. Real?time RT?PCR showed significant differential expression of immune privilege genes (TGF?2, Arginase 2, Indole 1, GATA3, POMC, VIP, CALCA, CALCB, IL?1RN, CD95L, CR1L, Serpine 1, HMOX1, IL6, LGALS3, HEBP1, THBS1, CD59 and LGALS1) in pluripotent stem cells/derivatives when compared to somatic cells. It is concluded that pluripotent stem cells/derivatives are predicted to be immunogenic, though evidences suggest some levels of potential immune privilege. In addition, differential immunogenicity may exist between different pluripotent stem cell lines and their derivatives
Characteristic expression of major histocompatibility complex and immune privilege genes in human pluripotent stem cells and their derivatives.
Sex, Specimen part
View SamplesTBR1 is a forebrain specific T-box transcription factor. Tbr1-/- mice have been characterized by defective axonal projections from cerebral cortex and abnormal neuronal migration of cerebral cortex and amygdala.
Tbr1 haploinsufficiency impairs amygdalar axonal projections and results in cognitive abnormality.
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Protein disulfide isomerase inhibition synergistically enhances the efficacy of sorafenib for hepatocellular carcinoma.
Specimen part, Cell line
View SamplesSorafenib is the only approved targeted drug for hepatocellular carcinoma (HCC), but its effect on patients survival gain is limited and varies over a wide range depending on patho-genetic conditions. Thus, enhancing the efficacy of sorafenib and finding a reliable predictive biomarker are crucuial to achieve efficient control of HCCs. In this study, we employed a systems approach by combining transcriptome analysis of the mRNA changes in HCC cell lines in response to sorafenib with network analysis to investigate the action and resistance mechanism of sorafenib. Gene ontology and gene set analysis revealed that proteotoxic stress and apoptosis modules are activated in the presence of sorafenib. Further analysis of the endoplasmic reticulum (ER) stress network model combined with in vitro experiments showed that introducing an additional stress by treating the orally active protein disulfide isomerase (PDI) inhibitor (PACMA 31) can synergistically increase the efficacy of sorafenib in vitro and in vivo, which was confirmed using a mouse xenograft model. We also found that HCC patients with high PDI expression show resistance to sorafenib and poor clinical outcomes, compared to the low PDI expression group. These results suggest that PDI is a promising therapeutic target for enhancing the efficacy of sorafenib and can also be a biomarker for predicting sorafenib responsiveness.
Protein disulfide isomerase inhibition synergistically enhances the efficacy of sorafenib for hepatocellular carcinoma.
Specimen part, Cell line
View SamplesSorafenib is the only approved targeted drug for hepatocellular carcinoma (HCC), but its effect on patients survival gain is limited and varies over a wide range depending on patho-genetic conditions. Thus, enhancing the efficacy of sorafenib and finding a reliable predictive biomarker are crucuial to achieve efficient control of HCCs. In this study, we employed a systems approach by combining transcriptome analysis of the mRNA changes in HCC cell lines in response to sorafenib with network analysis to investigate the action and resistance mechanism of sorafenib. Gene ontology and gene set analysis revealed that proteotoxic stress and apoptosis modules are activated in the presence of sorafenib. Further analysis of the endoplasmic reticulum (ER) stress network model combined with in vitro experiments showed that introducing an additional stress by treating the orally active protein disulfide isomerase (PDI) inhibitor (PACMA 31) can synergistically increase the efficacy of sorafenib in vitro and in vivo, which was confirmed using a mouse xenograft model. We also found that HCC patients with high PDI expression show resistance to sorafenib and poor clinical outcomes, compared to the low PDI expression group. These results suggest that PDI is a promising therapeutic target for enhancing the efficacy of sorafenib and can also be a biomarker for predicting sorafenib responsiveness.
Protein disulfide isomerase inhibition synergistically enhances the efficacy of sorafenib for hepatocellular carcinoma.
Specimen part, Cell line
View SamplesSorafenib is the only approved targeted drug for hepatocellular carcinoma (HCC), but its effect on patients survival gain is limited and varies over a wide range depending on patho-genetic conditions. Thus, enhancing the efficacy of sorafenib and finding a reliable predictive biomarker are crucuial to achieve efficient control of HCCs. In this study, we employed a systems approach by combining transcriptome analysis of the mRNA changes in HCC cell lines in response to sorafenib with network analysis to investigate the action and resistance mechanism of sorafenib. Gene ontology and gene set analysis revealed that proteotoxic stress and apoptosis modules are activated in the presence of sorafenib. Further analysis of the endoplasmic reticulum (ER) stress network model combined with in vitro experiments showed that introducing an additional stress by treating the orally active protein disulfide isomerase (PDI) inhibitor (PACMA 31) can synergistically increase the efficacy of sorafenib in vitro and in vivo, which was confirmed using a mouse xenograft model. We also found that HCC patients with high PDI expression show resistance to sorafenib and poor clinical outcomes, compared to the low PDI expression group. These results suggest that PDI is a promising therapeutic target for enhancing the efficacy of sorafenib and can also be a biomarker for predicting sorafenib responsiveness.
Protein disulfide isomerase inhibition synergistically enhances the efficacy of sorafenib for hepatocellular carcinoma.
Specimen part, Cell line
View Samples1. To identify potential effectors responsible for anti-tumorigenesis by targeting PLD1, we performed microarray in two Wnt-relevant colon cancer cells and analyzed transcriptional profile of genes that were differently expressed by inhibition and knockdown of PLD1
Targeting phospholipase D1 attenuates intestinal tumorigenesis by controlling β-catenin signaling in cancer-initiating cells.
Specimen part, Cell line
View SamplesMemory stabilization after learning requires transcriptional and translational regulations in the brain, yet the temporal molecular changes following learning have not been explored at the genomic scale. We here employed ribosome profiling and RNA sequencing to quantify the translational status and transcript levels in mouse hippocampus following contextual fear conditioning. We identified 104 genes that are dynamically regulated. Intriguingly, our analysis revealed novel repressive regulations in the hippocampus: translational suppression of ribosomal protein-coding genes at basal state; learning-induced early translational repression of specific genes; and late persistent suppression of a subset of genes via inhibition of ESR1/ERa signaling. Further behavioral analyses revealed that Nrsn1, one of the newly identified genes undergoing rapid translational repression, can act as a memory suppressor gene. This study unveils the yet unappreciated importance of gene repression mechanisms in memory formation. Overall design: The application of ribosome profiling and RNA-seq techniques to mouse hippocampi tissues after contextual fear conditioning and to mouse hippocampal primary cultures. Mouse ESCs were also examined.
Multiple repressive mechanisms in the hippocampus during memory formation.
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View SamplesIn Arabidopsis, jasmonate is required for stamen and pollen maturation. Mutants deficient in jasmonate synthesis, such as opr3, are male-sterile but become fertile when jasmonate is applied to developing flower buds. We have used ATH1 oligonucleotide arrays to follow gene expression in opr3 stamens for 22 hours following jasmonate treatment. In these experiments, a total of 821 genes were specifically induced by jasmonate and 480 repressed. Comparisons with data from previous studies indicate that these genes constitute a stamen-specific jasmonate transcriptome, with a large proportion (70%) of the genes expressed in the sporophytic tissue but not in the pollen. Bioinformatics tools allowed us to associate many of the induced genes with metabolic pathways that are likely up-regulated during jasmonate-induced maturation. Our pathway analysis led to the identification of specific genes within larger families of homologues that apparently encode stamen-specific isozymes. Extensive additional analysis of our dataset identified 13 transcription factors that may be key regulators of the stamen maturation processes triggered by jasmonate. Two of these transcription factors, MYB21 and MYB24, are the only members of subgroup 19 of the R2R3 family of MYB proteins. A myb21 mutant obtained by reverse genetics exhibited shorter anther filaments, delayed anther dehiscence and greatly reduced male fertility. A myb24 mutant was phenotypically wild type, but production of a myb21myb24 double mutant indicated that introduction of the myb24 mutation exacerbated all three aspects of the myb21 phenotype. Exogenous jasmonate could not restore fertility to myb21 or myb21myb24 mutant plants. Together with the data from transcriptional profiling, these results indicate that MYB21 and MYB24 are induced by jasmonate and mediate important aspects of the jasmonate response during stamen development.
Transcriptional regulators of stamen development in Arabidopsis identified by transcriptional profiling.
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