Project description:Upregulation of mir-125a suppresses the pro-survival protein Mcl1, producing the increase in apoptosis known to accompany the proliferative changes characteristic of intestinal adaptation. Our data highlight a potential role for microRNAs as mediators of the adaptive process and may facilitate the development of new therapeutic options for short bowel syndrome. Two-condition experiment: resected rat jejunum vs. pooled transected control, with dye-swaps.
Project description:Upregulation of mir-125a suppresses the pro-survival protein Mcl1, producing the increase in apoptosis known to accompany the proliferative changes characteristic of intestinal adaptation. Our data highlight a potential role for microRNAs as mediators of the adaptive process and may facilitate the development of new therapeutic options for short bowel syndrome.
Project description:MicroRNAs influence hematopoietic differentiation, but little is known about their effects on the stem cell state. Here, we report that the microRNA processing enzyme Dicer is essential for stem cell persistence in vivo and a specific microRNA, miR-125a controls the size of the stem cell population by regulating stem/progenitor cell (HSPC) apoptosis. Conditional deletion of Dicer revealed an absolute dependence for the multipotent HSPC population in a cell autonomous manner, with increased HSPC apoptosis in mutant animals. An evolutionarily conserved microRNA cluster containing miR-99b, let-7e and miR-125a was preferentially expressed in long term HSCs. miR-125a alone was capable of increasing the number of hematopoietic stem cells in vivo by more than eight fold. This was accomplished through a differentiation stage-specific reduction of apoptosis in immature hematopoietic progenitors, possibly through targeting multiple pro-apoptotic genes. Bak1 was directly down-regulated by miR-125a and expression of a 3’UTR-less Bak1 blocked miR-125a-induced hematopoietic expansion in vivo. These data demonstrate cell-state-specific regulation by microRNA and identify a unique microRNA functioning to regulate the stem cell pool size.
Project description:MicroRNAs influence hematopoietic differentiation, but little is known about their effects on the stem cell state. Here, we report that the microRNA processing enzyme Dicer is essential for stem cell persistence in vivo and a specific microRNA, miR-125a controls the size of the stem cell population by regulating stem/progenitor cell (HSPC) apoptosis. Conditional deletion of Dicer revealed an absolute dependence for the multipotent HSPC population in a cell autonomous manner, with increased HSPC apoptosis in mutant animals. An evolutionarily conserved microRNA cluster containing miR-99b, let-7e and miR-125a was preferentially expressed in long term HSCs. miR-125a alone was capable of increasing the number of hematopoietic stem cells in vivo by more than eight fold. This was accomplished through a differentiation stage-specific reduction of apoptosis in immature hematopoietic progenitors, possibly through targeting multiple pro-apoptotic genes. Bak1 was directly down-regulated by miR-125a and expression of a 3’UTR-less Bak1 blocked miR-125a-induced hematopoietic expansion in vivo. These data demonstrate cell-state-specific regulation by microRNA and identify a unique microRNA functioning to regulate the stem cell pool size. Bone marrow populations were FACS-sorted and profiled using a bead-based profiling platform. Long-term HSCs, short-term HSCs, multipotent progenitors, Lin-Kit+Sca+ cells, Lin-Kit+Sca- cells, Lin-Kit-Sca+ cells, Lin- cells and unfractionated whole bone marrow cells were prepared for total RNA using TriZol (Invitrogen) in replicates. For rare populations, cells from multiple mice were pooled. To perform microRNA profiling, 60 ng of total RNA were used for each sample.
Project description:Numerous cytokines have been shown to affect epithelial cell differentiation and proliferation through epithelial-mesenchymal interaction. Growing evidence suggests that platelet-derived growth factor (PDGF) signaling is an important mediator of these interactions. The purpose of this study was to evaluate the effect of PDGF-α on enterocyte turnover in a rat model of short bowel syndrome (SBS). Male rats were divided into four groups: Sham rats underwent bowel transection, Sham-PDGF-α rats underwent bowel transection and were treated with PDGF-α, SBS rats underwent a 75% bowel resection, and SBS-PDGF-α rats underwent bowel resection and were treated with PDGF-α. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. Illumina's Digital Gene Expression (DGE) analysis was used to determine PDGF-related gene expression profiling. PDGF-α and PDGF-α receptor (PDGFR-α) expression was determined using Real Time PCR. Western blotting was used to determine p-ERK, Akt1/2/3, bax and bcl-2 protein levels. SBS rats demonstrated a significant increase in PDGF-α and PDGFR-α expression in jejunum and ileum compared to sham animals. SBS-PDGF-α rats demonstrated a significant increase in bowel and mucosal weight, villus height and crypt depth in jejunum and ileum compared to SBS animals. PDGF-α expression in crypts increased in SBS rats (vs sham) and was accompanied by increased cell proliferation following PDGF-α administration. A significant decrease in cell apoptosis in this group was correlated with lower bax protein levels. In conclusion, in a rat model of SBS, PDGF-α stimulates enterocyte turnover, which is correlated with up-regulated PDGF-α receptor expression in the remaining small intestine. Animals were divided randomly into two experimental groups of 6 rats each. Group A rats underwent bowel transection and re-anastomosis (Sham), Group B animals underwent 75% bowel resection (SBS). Due to the quality of DNA, we performed final analysis from 5 jejunal samples (1 sham and 4 resected rats) and from 7 ileal samples (3 sham and 4 resected rats). Illumina's Digital Gene Expression (DGE) analysis using Illumina Rat Quad BeadChips was used to determine PDGF-related gene expression profiling.
Project description:Numerous cytokines have been shown to affect epithelial cell differentiation and proliferation through epithelial-mesenchymal interaction. Growing evidence suggests that platelet-derived growth factor (PDGF) signaling is an important mediator of these interactions. The purpose of this study was to evaluate the effect of PDGF-α on enterocyte turnover in a rat model of short bowel syndrome (SBS). Male rats were divided into four groups: Sham rats underwent bowel transection, Sham-PDGF-α rats underwent bowel transection and were treated with PDGF-α, SBS rats underwent a 75% bowel resection, and SBS-PDGF-α rats underwent bowel resection and were treated with PDGF-α. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined at sacrifice. Illumina's Digital Gene Expression (DGE) analysis was used to determine PDGF-related gene expression profiling. PDGF-α and PDGF-α receptor (PDGFR-α) expression was determined using Real Time PCR. Western blotting was used to determine p-ERK, Akt1/2/3, bax and bcl-2 protein levels. SBS rats demonstrated a significant increase in PDGF-α and PDGFR-α expression in jejunum and ileum compared to sham animals. SBS-PDGF-α rats demonstrated a significant increase in bowel and mucosal weight, villus height and crypt depth in jejunum and ileum compared to SBS animals. PDGF-α expression in crypts increased in SBS rats (vs sham) and was accompanied by increased cell proliferation following PDGF-α administration. A significant decrease in cell apoptosis in this group was correlated with lower bax protein levels. In conclusion, in a rat model of SBS, PDGF-α stimulates enterocyte turnover, which is correlated with up-regulated PDGF-α receptor expression in the remaining small intestine.
Project description:Purpose: In recent years, research has revealed the role of microRNAs (miRs) as important regulators of endothelial function. Notably, miR-125a is upregulated in the blood of patients with acute vascular diseases. Since miRNAs act out their function in networks, we aimed at investigating the presence of a miR-125a-related network regulating the endothelial barrier. Method: We investigated transcriptional changes of human umbilical cord endothelial cells (HUVEC) after miR-125a overexpression in an acute inflammatory in-vitro setting using Next Generation Sequencing. Briefly, primary HUVECs from five different donors were transfected either with hsa-miR-125a-5p or negative control (NC). After transfection HUVECs were cultivated for 18 hours and stimulated with TNF (25 ng/ml) for additional 6 hours. We compared the following groups: NC (18047-0001, 18047-0002, 18047-0003, 18047-0004, 18047-0005) versus miR125a: (18047-0006, 18047-0007, 18047-0008, 18047-0009, 18047-0010) Results: MiR-125a overexpression in inflammatory activated HUVECs significantly altered gene expression of 468 genes (FC: +1.25 to -1.25 p<0.01). We found eight potential miR-125a direct target genes involved in endothelial barrier function.
Project description:Neutrophil activation plays a critical role in the inflammatory response to gram-negative bacterial infections. Lipopolysaccharide (LPS) from gram-negative bacterial has been shown to be a major mediator of neutrophil activation to produce pro-inflammatory cytokines, chemokines and ROS which are important to tissue damage in LPS induced septic shock. We used microarrays to detail the global gene expression of neutrophils from miR-125a+/+ and miR-125a-/- mice after LPS stimulation.
Project description:This SuperSeries is composed of the following subset Series: GSE33689: Expression profiles of HSPCs overexpressing microRNA cluster 99b/let-7e/125a, miR-125a, miR-155 and empty vector. GSE33690: MicroRNA profiles of four developmentally related hematopoietic cell types isolated from the BM of B6 and D2 mice. Refer to individual Series
Project description:Recurrent mutations in ASXL1 are found in various hematological malignancies and are associated with poor prognosis. In particular, ASXL1 mutations are frequently found in patients with hematological malignancies associated with myelodysplasia including myelodysplastic syndromes (MDS), and chronic myelomonocytic leukemia. Although loss-of-function ASXL1 mutations promote myeloid transformation, a large subset of ASXL1 mutations is thought to result in stable truncation of ASXL1. Here we demonstrate that C-terminal truncating ASXL1 mutations (ASXL1-MT) inhibit myeloid differentiation and induce MDS-like disease in mice, displaying all the features of human MDS including multi-lineage myelodysplasia, pancytopenia and occasional progression to overt leukemia. Concerning the molecular mechanisms, ASXL1-MT derepressed expression of Hoxa9 and miR-125a through inhibiting PRC2-mediated methylation of H3K27. miR-125a targeted expression of a surface receptor Clec5a, which was found to supports for myeloid differentiation. In addition, HOXA9 expression was high in MDS patients with ASXL1 mutations while Clec5a expression was generally low in MDS patients. Thus, ASXL1-MT induced MDS-like disease in mice via derepression of Hoxa9 and miR-125a, and Clec5a downregulation. Our data provide evidence for a novel axis of MDS pathogenesis (ASXL1 mutations-upregulation of HoxA9 and miR-125a-downregulation of Clec5a) and implicate both ASXL1 mutants and miR-125a as therapeutic targets in MDS.