RNA from 5 mice with postdevelopmental knockout of myostatin and 5 mice with normal myostatin expression was analyzed with comprehensive oligonucleotide microarrays. Myostatin depletion affected the expression of several hundred genes at nominal P < 0.01, but fewer than a hundred effects were statistically significant according to a more stringent criterion (false discovery rate < 5%). Most of the effects were less than 1.5-fold in magnitude. In contrast to previously-reported effects of constitutive myostatin knockout, postdevelopmental knockout did not downregulate expression of genes encoding slow isoforms of contractile proteins or genes encoding proteins involved in energy metabolism. Several collagen genes were expressed at lower levels in the myostatin-deficient muscles, and this led to reduced tissue collagen levels as reflected by hydroxyproline content. Myostatin knockout tended to down-regulate the expression of sets of genes with promoter motifs for Smad3, Smad4, myogenin, NF-B, serum response factor, and numerous other transcription factors. Main conclusions: in mature muscle, myostatin is a key transcriptional regulator of collagen genes, but not genes encoding contractile proteins or genes encoding proteins involved in energy metabolism.
Skeletal muscle gene expression after myostatin knockout in mature mice.
Sex, Age, Specimen part
View SamplesIn order to investigate molecular events involved in the regulation of lymphoid lineage commitment, we crossed lamda5 reporter transgenic mice to mice where the GFP gene is inserted into the Rag1 locus. This allowed us to sub-fractionate common lymphoid progenitors (CLPs) and pre-pro-B cells into lamda5-Rag1low, lamda5-Rag1high and lamda5+Rag1high cells. Clonal in vitro differentiation analysis demonstrated that Rag1low cells gave rise to B/T and NK cells. Rag1high cells displayed reduced NK-cell potential with preserved capacity to generate B- and T-lineage cells while the lamda5+ cells were B-lineage restricted. Ebf1 and Pax5 expression was largely confined to the Rag1high populations. These cells also expressed a higher level of the surface protein LY6D providing an additional tool for the analysis of early lymphoid development. These data suggest that the classical CLP compartment composes a mixture of cells with more or less restricted lineage potentials opening new possibilities to investigate early hematopoiesis.
Single-cell analysis of the common lymphoid progenitor compartment reveals functional and molecular heterogeneity.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Combined Gene Expression and RNAi Screening to Identify Alkylation Damage Survival Pathways from Fly to Human.
Specimen part, Treatment
View SamplesDespite the high toxicity, alkylating agents are still at the forefront of several clinical protocols used to treat cancers. In this study, we investigated the mechanisms underlying alkylation damage responses, aiming to identify novel strategies to augment alkylating therapy efficacy. In this pursuit, we compared gene expression profiles of evolutionary distant cell types (D. melanogaster Kc167 cells, mouse embryonic fibroblasts and human cancer cells) in response to the alkylating agent methyl-methanesulfonate (MMS). We found that many responses to alkylation damage are conserved across species independent on their tumor/normal phenotypes. Key amongst these observations was the protective role of NRF2-induced GSH production primarily regulating GSH pools essential for MMS detoxification but also controlling activation of unfolded protein response (UPR) needed for mounting survival responses across species. An interesting finding emerged from a non-conserved mammalian-specific induction of mitogen activated protein kinase (MAPK)-dependent inflammatory responses following alkylation, which was not directly related to cell survival but stimulated the production of a pro-inflammatory, invasive and angiogenic secretome in cancer cells. Appropriate blocking of this inflammatory component blocked the invasive phenotype and angiogenesis in vitro and facilitated a controlled tumor killing by alkylation in vivo through inhibition of alkylation-induced angiogenic response, and induction of tumor healing.
Combined Gene Expression and RNAi Screening to Identify Alkylation Damage Survival Pathways from Fly to Human.
Specimen part, Treatment
View SamplesFull title: Genomics based analysis of interactions between developing B-lymphocytes and stromal cells reveal complex interactions and two-way communication
Genomics based analysis of interactions between developing B-lymphocytes and stromal cells reveal complex interactions and two-way communication.
Specimen part
View SamplesTumor cells that give rise to metastatic disease are a primary cause of cancer-related death and have not been fully elucidated in patients with lung cancer. Here, we addressed this question by using tissues from a mouse that develops metastatic lung adenocarcinoma owing to expression of mutant K-ras and p53. We identified a metastasis-prone population of tumor cells that differed from those with low metastatic capacity on the basis of having sphere-forming capacity in Matrigel cultures, increased expression of CD133 and Notch ligands, and relatively low tumorigenicity in syngeneic mice. Knockdown of jagged1 or pharmacologic inhibition of its downstream mediator phosphatidylinositol 3-kinase abrogated the metastatic but not the tumorigenic activity of these cells. We conclude from these studies on a mouse model of lung adenocarcinoma that CD133 and Notch ligands mark a population of metastasis-prone tumor cells and that the efficacy of Notch inhibitors in metastasis prevention should be explored.
The Notch ligand Jagged2 promotes lung adenocarcinoma metastasis through a miR-200-dependent pathway in mice.
Specimen part
View SamplesTumor growth is associated with a profound alteration of myelopoiesis, leading to recruitment of immunosuppressive cells known as myeloid-derived suppressor cells (MDSCs). Immuno-regulatory activity of both tumor-induced and BM-derived MDSCs (by GM-CSF and IL-6 treatment) was entirely dependent on C/EBP transcription factor (TF), a key component of the emergency myelopoiesis triggered by stress and inflammation. We used miR expression analysis to identify miRs which could drive MDSC recruitment/generation/activity by modulating specific TFs and pathway. In particular, we identified a miR signature of 79 miR differentially expressed between not suppressive CD11b+ cells and CD11b+ isolated from tumor mass and spleen of tumor-bearing mice. Moreover on the same samples we profiled gene expression with Affymetrix microarrays to perform an integrated analysis of mirna and gene expression.
miR-142-3p prevents macrophage differentiation during cancer-induced myelopoiesis.
Specimen part, Disease, Disease stage, Cell line
View SamplesTumor growth is associated with a profound alteration of myelopoiesis, leading to recruitment of immunosuppressive cells known as myeloid-derived suppressor cells (MDSCs). Analyzing the cytokines affecting myelo-monocytic differentiation produced by various experimental tumors, we found that GM-CSF, G-CSF, and IL-6 allowed a rapid generation of MDSCs from precursors present in mouse and human bone marrow (BM). BM-MDSCs induced by GM-CSF+IL-6 possessed the highest tolerogenic activity, as revealed by the ability to impair the priming of IFN- -producing CD8+ T cells upon in vivo adoptive transfer. Moreover, adoptive transfer of syngeneic, GM-CSF+IL-6-conditioned MDSCs to diabetic mice transplanted with allogeneic pancreatic islets resulted in long term acceptance of the allograft and correction of the diabetic status. Cytokines inducing MDSCs acted on a common molecular pathway. Immunoregulatory activity of both tumor-induced and BM-derived MDSCs was entirely dependent on C/EBP transcription factor, a key component of the emergency myelopoiesis triggered by stress and inflammation. Adoptive transfer of tumor antigen-specific CD8+ T lymphocytes resulted in therapy of established tumors only in mice lacking C/EBP in myeloid compartment. These data unveil another link between inflammation and cancer and identify a novel molecular target to control tumor-induced immune suppression.
Tumor-induced tolerance and immune suppression depend on the C/EBPbeta transcription factor.
Specimen part
View SamplesIn order to explore molecules whose expression is controlled by Slc39a13, we investigated gene expression profiling of primary osteoblast isolated from wild-type and Slc39a13 knockout mice.
The zinc transporter SLC39A13/ZIP13 is required for connective tissue development; its involvement in BMP/TGF-beta signaling pathways.
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