Project description:We assesed the transcriptional profiles of sorted SLAM-LSK hematopoietic stem cells (HSCs) during expansion in the murine fetal liver from WT and Jag1-null mutants at embryonic day 14.5 post-conception. The goals of the study are to compare the expression profiles of rapidly proliferating fetal HSCs when the Notch ligand Jag1 is specifically deleted in the hematopoietic compartment. We find that hematopoietic deletion of Jag1 negatively impacts the expression of critical hematopoietic cell fate and identity genes such as GATA2, Mllt3 and Hoxa7. Our study establishes a unique role for Notch signaling activation in the fetal liver by the hematopoietic Jag1 ligand.
Project description:Microarray gene expression experiments to identify differentially expressed genes and pathways in Jag1 conditional/null livers reveal up-regulation of many genes related to fibrosis and ECM interactions. 3 Jag1 conditional/null mutant mice versus 3 littermate wildtype control mice.
Project description:Endothelial cell (EC) sensing of fluid shear stress regulates atherosclerosis, a disease of arteries that causes heart attack and stroke. Atherosclerosis preferentially develops at regions of arteries exposed to low oscillatory shear stress (LOSS), whereas high shear regions are protected. We show using inducible EC-specific genetic deletion in hyperlipidaemic mice that the Notch ligands JAG1 and DLL4 have opposing roles in atherosclerosis. While endothelial Jag1 promoted atherosclerosis at sites of LOSS, endothelial Dll4 was atheroprotective. Analysis of porcine and murine arteries and cultured human coronary artery EC exposed to experimental flow revealed that JAG1 and its receptor NOTCH4 are strongly upregulated by LOSS. Functional studies in cultured cells and in mice with EC-specific deletion of Jag1 show that JAG1-NOTCH4 signalling drives vascular dysfunction by repressing endothelial repair. These data demonstrate a fundamental role for JAG1-NOTCH4 in sensing LOSS during disease, and suggest therapeutic targeting of this pathway to treat atherosclerosis.
Project description:Background: JAG-1 is a ligand of Notch signaling and can regulate cell differentiation and proliferation in cancers. Recent studies indicated that JAG1 is a gene associated with cancer progression. Therefore, we investigated the role of JAG1 in lung cancer progression. Methods: The expression of JAG1 was manipulated by overexpression or RNA silencing in several human lung cell lines. The effect of JAG1 on tumorigenesis and invasion was assessed by the cell anchorage-independent growth, cell proliferation, cell migration and invasion assays in vitro as well as metastasis in vivo. The potential downstream genes of JAG1 were identified by oligonucleotide microarrays and quantitative reverse transcription¡Vpolymerase chain reaction (RT-PCR). We further measured JAG1 expression in lung cancer specimens by RT-PCR. Correlation between JAG1 expression and overall survival of lung cancer patients was determined by using the log-rank test and multivariable Cox proportional hazards regression analysis. All statistical tests were two-sided. Results: JAG1 enhanced anchorage-independent growth, cell migration, invasion in the lower invasive cells, CL1-0. JAG1 also increased the capability of migration and invasion in the other two lung cancer cell lines (A549 and NCI-H226). The silencing of JAG1 inhibited migration and invasion activities of the higher invasive cells, CL1-5, by siRNA technology. The invasion-promoting activity of JAG1 was also demonstrated in vivo by using a mouse metastasis model. By microarray analysis, we found that the expression of heat shock 70kDa protein 2 (HSPA2) was activated by JAG1 overexpression and eliminated by JAG1 silencing. Moreover, lung cancer patients with high JAG1 expressing tumors had shorter overall survival than those with low-expressing tumors. Conclusion: JAG1 might be an oncogene which promotes colonogenesis and metastasis, and high JAG1 expression is associated with shorten survival in lung cancer. In this investigation, we used a lung cancer invasion cell model to identify the genes involved in cancer progression. JAG1 is a potential oncogene whose expression is correlated to the survival of patients with breast, prostate and liver cancers. However, the role of JAG1 in lung caner progression has not been reported, particularly in metastasis. Here, JAG1 was ectopically expressed in lower invasive lung cancer cell line its impact on colonogenesis, migration and invasiveness was assessed. The underlying mechanism was explored by JAG1-expressed transfectants and microarrays and the clinical relevance was evaluated by quantitative RT-PCR.
Project description:Microarray gene expression experiments to identify differentially expressed genes and pathways in Jag1 conditional/null livers reveal up-regulation of many genes related to fibrosis and ECM interactions.