Project description:Stem cell factor (SCF) mediated KIT receptor activation plays a pivotal role in mast cell growth, maturation and survival. However, the signaling events downstream from KIT are poorly understood. Mast cells express multiple regulatory subunits of class 1A PI3Kinase (PI3K) including p85α, p85β, p50α, and p55α. While it is known that PI3K plays an essential role in mast cells; the precise mechanism by which these regulatory subunits impact specific mast cell functions including growth, survival and cycling are not known. We show that loss of p85α impairs the growth, survival and cycling of mast cell progenitors (MCp). To delineate the molecular mechanism (s) by which p85α regulates mast cell growth, survival and cycling, we performed microarray analyses to compare the gene expression profile of MCps derived from WT and p85α-deficient mice in response to SCF stimulation. We identified 151 unique genes exhibiting altered expression in p85α-deficient cells in response to SCF stimulation compared to WT cells. Functional categorization based on DAVID bioinformatics tool and Ingenuity Pathway Analysis (IPA) software relates the altered genes due to lack of p85α to transcription, cell cycle, cell survival, cell adhesion, cell differentiation, and signal transduction. Our results suggest that p85α is involved in mast cell development through regulation of expression of growth, survival and cell cycle related genes. Two-condition experiment, wildtype vs. p85α-deficient mast cell progenitors stimulated with SCF. Biological replicates: 3 wildtype replicates, 3 p85α-deficient replicates.
Project description:Stem cell factor (SCF) mediated KIT receptor activation plays a pivotal role in mast cell growth, maturation and survival. However, the signaling events downstream from KIT are poorly understood. Mast cells express multiple regulatory subunits of class 1A PI3Kinase (PI3K) including p85α, p85β, p50α, and p55α. While it is known that PI3K plays an essential role in mast cells; the precise mechanism by which these regulatory subunits impact specific mast cell functions including growth, survival and cycling are not known. We show that loss of p85α impairs the growth, survival and cycling of mast cell progenitors (MCp). To delineate the molecular mechanism (s) by which p85α regulates mast cell growth, survival and cycling, we performed microarray analyses to compare the gene expression profile of MCps derived from WT and p85α-deficient mice in response to SCF stimulation. We identified 151 unique genes exhibiting altered expression in p85α-deficient cells in response to SCF stimulation compared to WT cells. Functional categorization based on DAVID bioinformatics tool and Ingenuity Pathway Analysis (IPA) software relates the altered genes due to lack of p85α to transcription, cell cycle, cell survival, cell adhesion, cell differentiation, and signal transduction. Our results suggest that p85α is involved in mast cell development through regulation of expression of growth, survival and cell cycle related genes.
Project description:Background and Purpose: Genome-wide association studies significantly link intracranial aneurysm (IA) to single-nucleotide polymorphisms (SNPs) in six genomic loci. To gain insight into the relevance of these IA associated SNPs, we aimed to identify regulatory regions and analyze overall gene expression in the human circle of Willis (CoW), on which these aneurysms develop. Methods: We performed chromatin immunoprecipitation and sequencing for histone modifications H3K4me1 and H3K27ac to identify regulatory regions, including distal enhancers and active promoters, in post mortem specimens of the human CoW. These experiments were complemented with RNA sequencing on the same specimens. We determined whether these regulatory regions overlap with IA associated SNPs, using computational methods. By combining our results with publicly available data, we investigated the effect of IA associated SNPs on the newly identified regulatory regions and linked them to potential target genes. Results: We find that IA associated SNPs are significantly enriched in CoW regulatory regions. Some of the IA associated SNPs that overlap with a regulatory region are likely to alter transcription factor binding, and in proximity to these regulatory regions are 102 genes that are expressed in the CoW. In addition, gene expression in the CoW is enriched for genes related to cell adhesion and the extracellular matrix. Conclusions: CoW regulatory regions link IA associated SNPs to genes with a potential role in the development of IAs. Our data refine previous predictions on SNPs associated with IA and provide a substantial resource from which candidates for follow-up studies can be prioritized.
Project description:Mast cells are phenotypically and functionally highly heterogeneous, and their state is possibly controlled by their local microenvironment. Therefore, concrete analyses are needed to understand whether mast cells act as powerful motivators or dispensable bystanders in specific diseases. Here, we evaluated the correlation between synovial mast cells and rheumatoid arthritis (RA) disease severity, and the efficacy of therapeutic interventions against mast cells. We showed that degranulation of mast cells in inflammatory synovial tissues of RA patients was induced via MAS-related G protein-coupled receptor X2 (MRGPRX2), and the expression of MHC class II (MHC II) and costimulatory molecules on mast cells were upregulated. These unique signaling response led to mast cell activation and promoted T cell responses, resulting in the progression of RA. Collagen-induced arthritis mouse models treated with a combination of anti-IL-17A and cromolyn sodium, a mast cell membrane stabilizer, showed significantly reduced clinical severity and decreased bone erosion. The findings of the present study suggest that synovial microenvironment-influenced mast cells contribute to RA and may provide a novel mast cell-targeting therapy for RA.
Project description:Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer fatalities in Western societies, characterized by high metastatic potential and resistance to chemotherapy. Critical molecular mechanisms of these phenotypical features still remain unknown, thus hampering the development of effective prognostic and therapeutic measures in PDAC. Here we show that transcriptional co-factor Transducin beta-like (TBL) 1 was over-expressed in both human and murine PDAC. Inactivation of TBL1 in human and mouse pancreatic cancer cells reduced cellular proliferation and enhanced chemosensitivity, correlating with diminished glucose uptake, glycolytic flux, and PI3kinase signaling. TBL1 deficiency both prevented and reversed pancreatic tumor growth in mice, triggering transcriptional PI3kinase inhibition also in vivo. As TBL1 mRNA levels were also found to correlate with overall and disease-free survival in a cohort of human PDAC patients and to predict therapy responsiveness in these subjects, TBL1 expression may serve both as a novel prognostic marker and molecular target in the treatment of human PDAC. Capan-1 cells were transfected with control-siRNA (#1027292, Qiagen) or siRNA against human TBL1 (SI04329514, Qiagen) and RNA was isolated 24h later
Project description:Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer fatalities in Western societies, characterized by high metastatic potential and resistance to chemotherapy. Critical molecular mechanisms of these phenotypical features still remain unknown, thus hampering the development of effective prognostic and therapeutic measures in PDAC. Here we show that transcriptional co-factor Transducin beta-like (TBL) 1 was over-expressed in both human and murine PDAC. Inactivation of TBL1 in human and mouse pancreatic cancer cells reduced cellular proliferation and enhanced chemosensitivity, correlating with diminished glucose uptake, glycolytic flux, and PI3kinase signaling. TBL1 deficiency both prevented and reversed pancreatic tumor growth in mice, triggering transcriptional PI3kinase inhibition also in vivo. As TBL1 mRNA levels were also found to correlate with overall and disease-free survival in a cohort of human PDAC patients and to predict therapy responsiveness in these subjects, TBL1 expression may serve both as a novel prognostic marker and molecular target in the treatment of human PDAC.
Project description:Full title: Comprehensive Characterization of Three-Dimensional Models for Prostate Cancer Growth and Invasion in Laminin-rich Extracellular Matrix Prostate Cancer (PrCa) cells undergo acinar morphogenesis and spheroid formation in three-dimensional (3D) culture, supported by laminin-rich extracellular matrix (lrECM, Matrigel). We developed miniaturized 3D model systems that facilitate investigation of morphogenesis and invasion of normal and PrCa cell lines in lrECM. Primary and non-transformed cell lines formed round structures with strong cell-cell contacts and epithelial polarization, lumen and a complete basal lamina (BL). In contrast, most PrCa cell lines formed either defective, “mass” spheroids with incomplete BL, or invasive “stellate” structures. The bioinformatic analyses of genome-wide mRNA expression data revealed massive alteration of key functional and signaling pathways in 3D cultures, with lipid and steroid metabolism, epigenetic reprogramming, and differentiation-related transcription factors induced across all cell lines by lrECM. In invasive cells, AKT, PI3Kinase, mTOR, and hedgehog signaling pathways were most highly activated, validated by small molecule inhibitors compounds specifically targeting key regulatory molecules. Compounds against AKT and PI3kinase pathways were significantly more effective in invasive cells, compared to mass or round/normal phenotype spheroids, and monolayer culture. A severe morphologic conversion was observed in PC-3 and PC-3M cells, transforming initially round, normal-appearing epithelial spheroids into rapidly invading cell masses. Markers for EMT (epithelial-mesenchymal transition) were highly expressed already in early stage, round spheroids prior to invasive conversion, and were not further increased in invasive cells. This indicates that PrCa cells can display extraordinary plasticity. EMT may be involved in providing a metastable genotype that allows morphological transformation, but is not be required for invasive processes themselves. Total RNA was obtained from non-transformed prostate epithelial cells and prostate cancer cells cultured in monolayer and three-dimensional laminin-rich extracellular matrix (growth factor-reduced Matrigel).
Project description:Immunoadsorption with subsequent immunoglobulin substitution (IA/IgG) represents a therapeutic approach for patients with dilated cardiomyopathy (DCM). Here, we studied which molecular cardiac alterations are initiated after this treatment. Transcription profiling of endomyocardial biopsies with Affymetrix whole genome arrays was performed on 33 paired samples of DCM patients collected before and six months after IA/IgG. Therapy-related effects on myocardial protein levels were analysed by label free proteome profiling for a subset of 23 DCM patients. Data were analysed regarding therapy-associated differences in gene expression and protein levels by comparing responders (defined by improvement of left ventricular ejection fraction ≥ 20% relative and ≥5% absolute) and non-responders. Responders to IA/IgG showed a decrease in serum N-terminal proBNP levels in comparison to baseline which was accompanied by a decreased expression of heart failure markers such as angiotensin converting enzyme 2 or periostin. However, despite clinical improvement even in responders IA/IgG did not trigger general inversion of DCM associated molecular alterations in myocardial tissue. Transcriptome profiling revealed reduced gene expression for connective tissue growth factor, fibronectin, and collagen type I in responders. In contrast, in non-responders after IA/IgG, for fibrosis associated genes and proteins showed elevated levels whereas values were reduced or maintained in responders. Thus, improvement of LV function after IA/IgG seems to be related to a reduced gene expression of heart failure markers and pro-fibrotic molecules as well as reduced fibrosis progression.
Project description:Frequent mutations in the regulatory p85a subunit (PIK3R1 gene) were identified in colon cancer and shown to promote cell survival, Akt activation, anchorage independent cell growth and oncogenesis. A number of tumor samples including colon, breast, NSCLC and gastric were also profiled for co-occurrence of chromosomal copy number changes including gene amplifications in PI3K pathway on Affymterix 100K SNP arrays. Experiment Overall Design: Analysis of copy number changes in several different tumor types
Project description:Microenvironment-based alterations in mast cell phenotypes influence the susceptibility to anaphylaxis, yet the mechanisms underlying proper maturation of mast cells toward an anaphylaxis-sensitive phenotype are incompletely understood. Here we report that PLA2G3, a mammalian homolog of anaphylactic bee venom phospholipase A2, regulates this process. PLA2G3 secreted from mast cells is coupled with fibroblastic lipocalin-type PGD2 synthase (L-PGDS) to provide PGD2, which facilitates mast cell maturation via PGD2 receptor (DP1). Mice lacking PLA2G3, L-PGDS or DP1, mast cell-deficient mice reconstituted with PLA2G3- or DP1-null mast cells, or mast cells cocultured with L-PGDS-ablated fibroblasts exhibited impaired mast cell maturation and anaphylaxis. Thus, we describe a lipid-driven PLA2G3-L-PGDS-DP1 loop that drives mast cell maturation. Mast cell maturation; immature and mature bone marrow-derived mast cells (BMMCs); Four-condition experiment (mature BMMCs vs immature BMMCs, Pla2g3M-bM-^@M-^S/M-bM-^@M-^S vs Pla2g3+/+); 3 replicates of Pla2g3+/+ BMMCs, 4 replicates of Pla2g3M-bM-^@M-^S/M-bM-^@M-^S BMMCs, 4 replicates of Pla2g3+/+ cocultured BMMCs, 3 replicates of Pla2g3M-bM-^@M-^S/M-bM-^@M-^S cocultured BMMCs