Project description:Analysis of differential gene expression. The influence of a constitutively activated mutant Kit receptor on gene expression in fetal hematopoietic cells was analyzed. Results provide information of genes and cellular processes that are influenced by Kit signaling. Total RNA obtained from embryonic day E13.5 fetal liver of double transgenic R26-LSL-KITD816V:Vav-iCre mice compared to single transgenic controls. R26-LSL-KITD816V mice have been registered with the mouse genome database (MGI:5516508, allele named Gt(ROSA)26sorTM1(GFP-cKIT*)Hsc). Vav-iCre mice have been described by De Boer et al. in 2003.
Project description:Haematopoiesis-specific Fh1 deletion causes lethal foetal liver haematopoietic defects. To understand the impact of Fh1 deletion on the transcriptome of foetal liver Lin- c-Kit+ cells we preformed microarray analysis. To conditionally delete Fh1 in the foetal liver we used the Vav-iCre recombinase and a Fh1 flox allele. Foetal livers were dissected and used to generate a single cell suspension. Lin- c-Kit+ cells were FACS sorted and lysed for total RNA preparation. We collected samples from 4 experimental animals (Fh1 fl/fl; Vav-iCre/+) and 3 control animals (Fh1 fl/fl).
Project description:MiRNAs have the potential to regulate cellular differentiation programs. However, miRNA-deficiency in primary hematopoietic stem cells (HSCs) results in HSC depletion in mice, leaving the question of whether miRNAs play a role in early-lineage decisions unanswered. To address this issue, we deleted Dicer1, which encodes an essential RNaseIII enzyme for miRNA biogenesis, in murine CCAAT/enhancer-binding protein alpha (C/EBPA)-positive myeloid-committed progenitors in vivo. In contrast to the results in HSCs, we found that miRNA depletion affected neither the number of myeloid progenitors nor the percentage of C/EBPA-positive progenitor cells. Analysis of gene-expression profiles from wild type and Dicer1-deficient granulocyte-macrophage progenitors (GMPs) revealed that 20 miRNA families were active in GMPs. Of the derepressed miRNA targets in Dicer1-null GMPs, 27% are normally exclusively expressed in HSCs or are specific for multi-potent progenitors and erythropoiesis, indicating an altered gene-expression landscape. Dicer1-deficient GMPs were defective in myeloid development in vitro and exhibited an increased replating capacity, indicating a regained self-renewal potential of these cells. In mice, Dicer1 deletion blocked monocytic differentiation, depleted macrophages and caused myeloid dysplasia with morphological features of Pelger-Huët anomaly. These results provide evidence for a miRNA-controlled switch for a cellular program of self-renewal and expansion towards myeloid differentiation in GMPs. To generate Cebpa-Cre;R26-LSL-Eyfp;Dicer1wt/fl/Dicer1fl/fl mice, we crossed mice that contain floxed Dicer1 alleles (Dicer1fl) with Cebpa-Cre;R26-LSL-Eyfp reporter mice 2. Fetal livers were obtained on embryonic day (E) 13.5. Routine genotyping of Dicer1; Cebpa-Cre;R26-LSL-Eyfp mice was performed by PCR assays of DNA from tail or toe biopsies. For transplantation, 6 to 8-week-old recipient mice (C57Bl/6, Jackson Laboratories) were irradiated (8.5 Gy) and tail-vein injected with fetal liver single-cell suspensions. Typically, cells from each fetal liver were transplanted into two recipient mice. Hematopoietic tissues were analyzed 6-10 weeks post transplantation. EYFP positive GMPs from the bone marrow of Dicer wt control (n=3), Dicer -/wt (n=3 and Dicer fl/fl (n=3) were sorted and analyzed for gene expression profiles.
Project description:Chemokine signaling is important for the seeding of different sites by hematopoietic stem cells during development. Serum Response Factor (SRF) controls multiple genes governing adhesion and migration, mainly by recruiting members of the Myocardin-Related Transcription Factor (MRTF) family of G-actin regulated cofactors. We used vav-iCre to inactivate MRTF-SRF signaling early during hematopoietic development. In both Srf- and Mrtf-deleted animals, hematopoiesis in fetal liver and spleen is intact, but does not become established in fetal bone marrow. Srf-null HSC/Ps (hematopoietic stem/progenitor cells) fail to effectively engraft in transplantation experiments, exhibiting normal proximal signaling responses to SDF-1, but reduced adhesiveness, F-actin assembly, and reduced motility. Srf-null HSC/Ps fail to polarise in response to SDF-1, and cannot migrate through restrictive membrane pores to SDF-1 or Scf in vitro. Mrtf-null HSC/Ps were also defective in chemotactic responses to SDF-1. MRTF-SRF signaling is thus critical for the response to chemokine signaling during hematopoietic development.
Project description:Liver mitochondria play a central role in metabolic adaptations to changing nutritional states, yet their dynamic regulation upon anticipated changes in the energy state has remained unaddressed. Here, we show that sensory food perception rapidly induces mitochondrial fission in the liver via protein kinase B/AKT-dependent phosphorylation of serine 131 of the Mitochondrial fission factor (MFFS131), a response mediated via activation of hypothalamic Pro-opiomelanocortin (POMC)-expressing neurons. A non-phosphorylatable MFFS131G knock-in mutation abrogates AKT-induced mitochondrial fragmentation in vitro. In vivo, MFFS131G knock-in mice display altered liver mitochondrial dynamics upon refeeding and impaired insulin stimulated suppression of gluconeogenesis. Collectively, we reveal a critical role for rapid activation of a hypothalamic/liver axis to adapt mitochondrial function to anticipated changes of nutritional state in control of hepatic glucose metabolism. R26-fl-Akt-C mice Mice carrying a conditional myristoylation tagged Akt-C transgene in the ROSA26 locus were used to activate AKT in the liver with a liver specific Cre-dependent virus. The generation of this line has been described previously (V. Kohlhaas et al, 2021) For AAV mediated liver-specific delivery of Cre, R26-fl-Akt-C or control mice were injected with a AAV8-TBG-iCre virus (VB1724, Vector Biolabs). This repository contains two experiments a) Liver of liver active Akt-CA and b) Insulin stimulation of primary heptocytes. Please note that replicate one of the hepatocyte dataset have been removed from the analysis due to the limited number of posphosites compared to others.
Project description:Chemokine signaling is important for the seeding of different sites by hematopoietic stem cells during development. Serum Response Factor (SRF) controls multiple genes governing adhesion and migration, mainly by recruiting members of the Myocardin-Related Transcription Factor (MRTF) family of G-actin regulated cofactors. We used vav-iCre to inactivate MRTF-SRF signaling early during hematopoietic development. In both Srf- and Mrtf-deleted animals, hematopoiesis in fetal liver and spleen is intact, but does not become established in fetal bone marrow. Srf-null HSC/Ps (hematopoietic stem/progenitor cells) fail to effectively engraft in transplantation experiments, exhibiting normal proximal signaling responses to SDF-1, but reduced adhesiveness, F-actin assembly, and reduced motility. Srf-null HSC/Ps fail to polarise in response to SDF-1, and cannot migrate through restrictive membrane pores to SDF-1 or Scf in vitro. Mrtf-null HSC/Ps were also defective in chemotactic responses to SDF-1. MRTF-SRF signaling is thus critical for the response to chemokine signaling during hematopoietic development. Strand specific RNA sequencing (RNA-seq) in sorted WT and SRF deleted LSK cells with or without a 30 minute SDF stimulation and validation by qRT-PCR
Project description:The mRNA m6A reader YTHDF2 is overexpressed in a broad spectrum of human acute myeloid leukemias (AML). To understand the role of YTHDF2 in AML, we generated m6A meRIP-seq libraries form Ythdf2fl/fl; Vav-iCre (Ythdf2CKO) pre-leukemic cells.
Project description:Background: Intestine epithelial hypoxia-inducible factor-1α (HIF-1α) plays a critical role in maintaining gut barrier function. The aim of this study was to determine genetic activation of intestinal HIF-1α ameliorates western diet-induced metabolic dysfunction–associated steatotic liver disease (MASLD). Methods: Male and/or female intestinal epithelial-specific Hif1α overexpression mice (Hif1α LSL/LSL;VilERcre) and wild-type littermates (Hif1α LSL/LSL) were fed with regular chow diet, high fructose (HFr) or high-fat (60% Kcal) high-fructose diet (HFHFr) for 8 weeks. Metabolic phenotypes were profiled. Results: Male Hif1α LSL/LSL;VilERcre mice exhibited markedly improved glucose tolerance compared to Hif1α LSL/LSL mice in response to HFr diet. Eight weeks HFHFr feeding led to obesity in both Hif1α LSL/LSL;VilERcre and Hif1α LSL/LSL mice. However, male Hif1α LSL/LSL;VilERcre mice exhibited markedly attenuated hepatic steatosis along with reduced liver size and liver weight compared to male Hif1α LSL/LSL mice. Moreover, HFHFr-induced systemic inflammatory responses were mitigated in male Hif1α LSL/LSL;VilERcre mice compared to male Hif1α LSL/LSL mice and those responses were not evident in female mice. Ileum RNA-seq analysis revealed that glycolysis/gluconeogenesis was up in male Hif1α LSL/LSL;VilERcre mice accompanied by increased epithelial cell proliferation. Conclusion: Our data provide evidence that genetic activation of intestinal HIF-1α markedly ameliorates western diet-induced MASLD in a sex-dependent manner. The underlying mechanism is likely attributed to HIF-1α activation induced upregulation of glycolysis, which, in turn, leading to enhanced epithelial cell proliferation and augmented gut barrier function.