Project description:Hepatocyte nuclear factor 4alpha (HNF-4alpha) (nuclear receptor 2A1) is an essential regulator of hepatocyte differentiation and function. Genetic and molecular evidence suggests that the tissue-restricted expression of HNF-4alpha is regulated mainly at the transcriptional level. As a step toward understanding the molecular mechanism involved in the transcriptional regulation of the human HNF-4alpha gene, we cloned and analyzed a 12.1-kb fragment of its upstream region. Major DNase I-hypersensitive sites were found at the proximal promoter, the first intron, and the more-upstream region comprising kb -6.5, -8.0, and -8.8. By the use of reporter constructs, we found that the proximal-promoter region was sufficient to drive high levels of hepatocyte-specific transcription in transient-transfection assays. DNase I footprint analysis and electrophoretic mobility shift experiments revealed binding sites for HNF-1alpha and -beta, Sp-1, GATA-6, and HNF-6. High levels of HNF-4alpha promoter activity were dependent on the synergism between either HNF-1alpha and HNF-6 or HNF-1beta and GATA-6, which implies that at least two alternative mechanisms may activate HNF-4alpha gene transcription. Chromatin immunoprecipitation experiments with human hepatoma cells showed stable association of HNF-1alpha, HNF-6, Sp-1, and COUP-TFII with the promoter. The last factor acts as a repressor via binding to a newly identified direct repeat 1 (DR-1) sequence of the human promoter, which is absent in the mouse homologue. We present evidence that this sequence is a bona fide retinoic acid response element and that HNF-4alpha expression is upregulated in vivo upon retinoic acid signaling.
Project description:Microglia isolated from glioma patients gain anti-tumor activities upon poly (I:C) stimulation. Expression profiles of human tumor-infiltrating microglia/macrophages before (untreated) and after treatment with poly (I:C) for 48h (induced). Tumor-infiltrating microglia/macrophages were isolated from freshly excised brain tumors
Project description:Microglia and neuroinflammation play an important role in the development and progression of Alzheimer’s disease (AD). Inositol polyphosphate-5-phosphatase D (INPP5D) is a myeloid-expressed gene genetically-associated with AD. Through unbiased analyses of RNA and protein profiles in INPP5D-disrupted iPSC-derived human microglia, we find that reduction in INPP5D activity is associated with molecular profiles consistent with disrupted autophagy and inflammasome activation. These findings are validated through targeted pharmacological experiments which demonstrate that reduced INPP5D activity induces the formation of the NLRP3 inflammasome, cleavage of CASP1, and secretion of IL-1 and IL-18. Further, in-depth analyses of human brain tissue across hundreds of individuals using a multi-analytic approach provides evidence that a reduction in function of INPP5D in microglia results in inflammasome activation in AD. These findings provide insights into the molecular mechanisms underlying microglia-mediated processes in AD and highlight the inflammasome as a potential therapeutic target for modulating INPP5D-mediated vulnerability to AD.