Project description:Previous studies have focused on the combined glucolipoxicity that is presence of high glucose and free fatty acid levels effect on insulin gene expression, but the effect of high FFA and normal glucose level on insulin expression is unkown. Here we observed that palmitate can inhibit insulin translation. And we identified a novel insulin mrna binding protein DDX1 that is responsible for fatty acid mediated insulin translation inhibition. Palmitate treatment causes phosphorylation of DDX1 at S295 and dissociation from insulin mRNA, which decreases insulin translation.
Project description:A time course of orotic acid induced fatty liver disease. Kyoto and Wistar strain rats were exposed to orotic acid for days 1, 3 and 14. Controls are also included.
Project description:A total of 37,185 transcripts were detected from RNA extracts from primary cultured astrocytes, and neurons isolated from Rattus hippocampus. After exposing astrocytes to insulin (200 nM) for 6h, 883 transcripts were upregulated 2SD or greater and 852 transcripts were downregulated 2SD or greater compared with vehicle treated control astrocyte cultures. This general pattern of gene expression was maintained for at least 12h in astrocytes where the expression of 811 genes were increased and 849 genes decreased compared with vehicle treated astrocytes. Informatic interrogation of genes with expression greater or less than 2 SD at the 6h and 12h time points in astrocytes identified signaling pathways associated with fatty acid activation, fatty acid β-oxidation, cAMP, gap junction, dendritic cell maturation ceramide degradation, triacylglycerol degradation and phospholipase activation. The functional association of gene changes in astrocytes after treatment with insulin for 6 and 12 h were almost exclusively related to the synthesis and storage of diacylglycerides, sterols, and other lipids. After exposing primary cultured Rattus hippocampal neurons to insulin (200 nM) for 6h, 753 genes were upregulated and 660 genes downregulated. This general pattern of gene expression was maintained for at least 12h when 768 genes were upregulated versus 736 genes downregulated in insulin treated neurons. Changes in gene expression profiles of neurons exposed to insulin for 6h, and 12h identified signaling pathways associated with actin-based motility, tight junctions, dendritic cell maturation, serotonin receptor, CREB (cAMP-response element binding protein), and axonal guidance. The functional association of gene changes in neurons after treatment with insulin for 6h, and 12h were largely related to neuroprotective/neurotrophic effects including tyrosine kinase tec-1 activation, synaptogenesis activation, and regulation of actin based cytoskeleton activation by the Rho family GTPases. These data suggest that insulin regulates neurotrophic signaling/functions in neurons and primary regulates lipid metabolism associated with fatty acid oxidation in astrocytes.
Project description:DEAD-box helicase 1 (DDX1) is a multifunction protein involved in diverse cellular processes including transcription, viral replication, mRNA/miRNA processing, and tRNA splicing. Here, we report a novel function of DDX1 in mRNA alternative splicing in pancreatic β cells. By performing integrated data analysis of high-throughput RNA sequencing (RNA-Seq), and cross-linking and immunoprecipitation coupled with deep sequencing (CLIP-Seq), we identify hundreds of alternative splicing genes that are targeted by DDX1. These DDX1-targeted alternative splicing genes are mainly associated with calcium ion binding, high voltage-gated calcium channel, and transmembrane transporter. Functionally, silencing DDX1 impairs calcium influx and insulin secretion in the pancreatic β cells. These results reveal an important role for DDX1 in the regulation of gene alternative splicing and insulin secretion in pancreatic β cells.
Project description:Inflammation is a key component of pathological angiogenesis. Here we induce cornea neovascularisation using sutures placed into the cornea, and sutures are removed to induce a regression phase. We used whole transcriptome microarray to monitor gene expression profies of several genes