Endothelial differentiation occurs during normal vascular development in the developing embryo. Mouse embryonic stem (ES) cells were used to further define the molecular mechanisms of endothelial differentiation. By flow cytometry a population of VEGF-R2 positive cells was identified as early as 2.5 days after differentiation of ES cells, and a subset of VEGF-R2 + cells, that were CD41+ positive at 3.5 days. A separate population of VEGF-R2+ stem cells expressing the endothelial-specific marker CD144 (VE-cadherin) was also identified at this same time point. Microarray analysis of >45,000 transcripts was performed on RNA obtained from cells expressing VEGF-R2, CD41, and CD144.
Gene expression analysis of embryonic stem cells expressing VE-cadherin (CD144) during endothelial differentiation.
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View SamplesNormal adult liver is uniquely capable of renewal
Restoration of liver mass after injury requires proliferative and not embryonic transcriptional patterns.
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View SamplesIn this study, we performed the gene expression analysis of the Normal, Diabetic and AAT treated NOD mice to elucidate the transcriptional changes induced by AAT. This will assist in identifying the biological processes / pathways involved in curative mechanism of AAT.
Curative and beta cell regenerative effects of alpha1-antitrypsin treatment in autoimmune diabetic NOD mice.
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View SamplesKnockdown of the transcription factor PU.1 (Spi1) leads to acute myeloid leukemia (AML) in mice. We examined the transcriptome of PU.1 knockdown hematopoietic stem cells (HSC) in the preleukemic phase by linear amplification and genome-wide array analysis to identify transcriptional changes preceding malignant transformation. Hierarchical cluster analysis and principal component analysis clearly distinguished PU.1 knockdown from wildtype HSC. Jun family transcription factors c-Jun and JunB were among the top downregulated targets. Retroviral restoration of c-Jun expression in bone marrow cells of preleukemic mice partially rescued the PU.1-initiated myelomonocytic differentiation block. Lentiviral restoration of JunB at the leukemic stage led to reduced clonogenic growth, loss of leukemic self-renewal capacity, and prevented leukemia in transplanted NOD-SCID mice. Examination of 305 AML patients confirmed the correlation between PU.1 and JunB downregulation and suggests its relevance in human disease. These results delineate a transcriptional pattern that precedes the leukemic transformation in PU.1 knockdown HSC and demonstrate that decreased levels of c-Jun and JunB contribute to the development of PU.1-induced AML by blocking differentiation (c-Jun) and increasing self-renewal (JunB). Therefore, examination of disturbed gene expression in HSC can identify genes whose dysregulation is essential for leukemic stem cell function and are targets for therapeutic interventions.
Essential role of Jun family transcription factors in PU.1 knockdown-induced leukemic stem cells.
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View SamplesIn this study that was specifically designed to identify early stages of glaucoma in DBA/2J mice, we used genome-wide expression profiling and a series of computational methods. Our methods successfully subdivided eyes with no detectable glaucoma by conventional assays into molecularly defined stages of disease. These stages represent a temporally ordered sequence of glaucoma states. Using an array of tools, we then determined networks and biological processes that are altered at these early stages. Our strategy proved very sensitive, suggesting that similar approaches will be valuable for uncovering early processes in other complex, later-onset diseases. Early changes included upregulation of both the complement cascade and endothelin system, and so we tested the therapeutic value of separately inhibiting them. Mice with a mutation in the complement component 1a gene (C1qa) were robustly protected from glaucoma with the protection being among the greatest reported. Similarly, inhibition of the endothelin system was strongly protective. Since EDN2 is potently vasoconstrictive and was produced by microglial/macrophages, our data provide a novel link between these cell types and vascular dysfunction in glaucoma. Targeting early events such as the upregulation of the complement and endothelin pathways may provide effective new treatments for human glaucoma.
Molecular clustering identifies complement and endothelin induction as early events in a mouse model of glaucoma.
Sex, Age, Specimen part
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