Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using human vascular endothelial cells (ECV304) as the target, we studied the effect of caveolin (CAV)-1 in the course of insulin-stimulated expression of plasminogen activator inhibitor (PAI)-1. The appropriate single-stranded oligonucleotides representing the RNAi CAV-1 gene were analyzed by Ambion software. After annealing to generate double-stranded oligonucleotides (ds oligo), it was cloned into the pENTR/U6 entry vector containing RNA polymerase III expression element by T4 DNA ligase. The short hairpin (shRNA) sequences transferred from the pENTR/U6 entry were cloned into the pLenti6/BLOCK-iT-DEST vector with an LR recombination reaction. After identification by sequencing, we successfully constructed the CAV-1 RNAi lentiviral expression system using Gateway technology. Silencing efficiency was assayed by real-time reverse transcription-polymerase chain reaction, immunofluorescence staining and Western blotting. ECV304 cells were cultured in the medium containing different concentrations of insulin (1x10(-9) to 1x10(-7) M) with the CAV-1 gene silenced or not. The expression level and subcellular localization of PAI-1 and CAV-1 were compared using reverse transcription-polymerase chain reaction, immunofluorescence staining and Western blot assay. The results showed that the potent inhibition of CAV-1 expression could reach 85%, and it was specific to the CAV-1-derived shRNA, not the S100A13-derived shRNA. There was no dramatic difference in PAI-1 expression between the RNAi+ and RNAi- ECV304 cells incubated with physiological insulin, but PAI-1 protein did accumulate under the cell membrane. As the concentration of insulin increased, the expression of PAI-1 was up-regulated, whereas the expression of CAV-1 attenuated. Furthermore, PAI-1 clearly augmented after CAV-1 knockdown. These results indicated that hyperinsulinism could promote PAI-1 expression by inhibiting CAV-1, and stabilizing or up-regulating CAV-1 expression in endothelial cells might reduce complications of the great vessels and capillary vessels in diabetes.
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PMID:Small interfering RNA-mediated caveolin-1 knockout on plasminogen activator inhibitor-1 expression in insulin-stimulated human vascular endothelial cells. 1734 62

Glucocorticoid receptor alpha (GRalpha) and peroxisome proliferator-activated receptor alpha (PPARalpha) are transcription factors with clinically important immune-modulating properties. Either receptor can inhibit cytokine gene expression, mainly through interference with nuclear factor kappaB (NF-kappaB)-driven gene expression. The present work aimed to investigate a functional cross-talk between PPARalpha- and GRalpha-mediated signaling pathways. Simultaneous activation of PPARalpha and GRalpha dose-dependently enhances transrepression of NF-kappaB-driven gene expression and additively represses cytokine production. In sharp contrast and quite unexpectedly, PPARalpha agonists inhibit the expression of classical glucocorticoid response element (GRE)-driven genes in a PPARalpha-dependent manner, as demonstrated by experiments using PPARalpha wild-type and knockout mice. The underlying mechanism for this transcriptional antagonism relies on a PPARalpha-mediated interference with the recruitment of GRalpha, and concomitantly of RNA polymerase II, to GRE-driven gene promoters. Finally, the biological relevance of this phenomenon is underscored by the observation that treatment with the PPARalpha agonist fenofibrate prevents glucocorticoid-induced hyperinsulinemia of mice fed a high-fat diet. Taken together, PPARalpha negatively interferes with GRE-mediated GRalpha activity while potentiating its antiinflammatory effects, thus providing a rationale for combination therapy in chronic inflammatory disorders.
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PMID:PPARalpha blocks glucocorticoid receptor alpha-mediated transactivation but cooperates with the activated glucocorticoid receptor alpha for transrepression on NF-kappaB. 1937 72

Levels of pituitary growth hormone (GH), a metabolic homeostatic factor with strong lipolytic activity, are decreased in obese individuals. GH declines prior to the onset of weight gain in response to excess caloric intake and hyperinsulinemia; however, the mechanism by which GH is reduced is not clear. We used transgenic mice expressing the human GH (hGH) gene, GH1, to assess the effect of high caloric intake on expression as well as the local chromosome structure of the intact GH1 locus. Animals exposed to 3 days of high caloric intake exhibited hyperinsulinemia without hyperglycemia and a decrease in both hGH synthesis and secretion, but no difference in endogenous production of murine GH. Efficient GH1 expression requires a long-range intrachromosomal interaction between remote enhancer sequences and the proximal promoter region through "looping" of intervening chromatin. High caloric intake disrupted this interaction and decreased both histone H3/H4 hyperacetylation and RNA polymerase II occupancy at the GH1 promoter. Incorporation of physical activity muted the effects of excess caloric intake on insulin levels, GH1 promoter hyperacetylation, chromosomal architecture, and expression. These results indicate that energy homeostasis alters postnatal hGH synthesis through dynamic changes in the 3-dimensional chromatin structure of the GH1 locus, including structures required for cell type specificity during development.
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PMID:Energy homeostasis targets chromosomal reconfiguration of the human GH1 locus. 2529 35

Endocrinopathic laminitis is pathologically similar to the multi-organ dysfunction and peripheral neuropathy found in human patients with metabolic syndrome. Similarly, endocrinopathic laminitis has been shown to partially result from vascular dysfunction. However, despite extensive research, the pathogenesis of this disease is not well elucidated and laminitis remains without an effective treatment. Here, we sought to identify novel proteins and pathways underlying the development of equine endocrinopathic laminitis. Healthy Standardbred horses (n = 4/group) were either given an electrolyte infusion, or a 48-h euglycemic-hyperinsulinemic clamp. Cardiac and lamellar tissues were analyzed by mass spectrometry (FDR = 0.05). All hyperinsulinemic horses developed laminitis despite being previously healthy. We identified 514 and 709 unique proteins in the cardiac and lamellar proteomes, respectively. In the lamellar tissue, we identified 14 proteins for which their abundance was significantly increased and 13 proteins which were significantly decreased in the hyperinsulinemic group as compared to controls. These results were confirmed via real-time reverse-transcriptase PCR. A STRING analysis of protein-protein interactions revealed that these increased proteins were primarily involved in coagulation and complement cascades, platelet activity, and ribosomal function, while decreased proteins were involved in focal adhesions, spliceosomes, and cell-cell matrices. Novel significant differentially expressed proteins associated with hyperinsulinemia-induced laminitis include talin-1, vinculin, cadherin-13, fibrinogen, alpha-2-macroglobulin, and heat shock protein 90. In contrast, no proteins were found to be significantly differentially expressed in the heart of hyperinsulinemic horses compared to controls. Together, these data indicate that while hyperinsulinemia induced, in part, microvascular damage, complement activation, and ribosomal dysfunction in the lamellae, a similar effect was not seen in the heart. In brief, this proteomic investigation of a unique equine model of hyperinsulinemia identified novel proteins and signaling pathways, which may lead to the discovery of molecular biomarkers and/or therapeutic targets for endocrinopathic laminitis.
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PMID:Differential Proteomic Expression of Equine Cardiac and Lamellar Tissue During Insulin-Induced Laminitis. 3259 66