Search results for "regulation"
showing 10 items of 4463 documents
Verso la disciplina giuridica della sharing economy
2015
Nonostante la crescente attenzione dei media e le tante dispute a livello globale sulle regole applicabili, la sharing economy è un fenomeno ancora trascurato dall’analisi giuridica. Questo saggio intende offrire un primo inquadramento delle pratiche economiche di condivisione, in cui piattaforme digitali facilitano lo sfruttamento in comune di beni e l’erogazione di servizi tra «pari», per poi valutare le sfide che i cambiamenti descritti presentano per il regolatore. Le ricadute giuridiche dei nuovi modelli di produzione e scambio vanno ben oltre il conflitto in atto tra esponenti dei comparti tradizionali e nuovi attori economici, sollecitando una ridefinizione dei fallimenti del mercato…
von Hippel-Lindau Protein-Mediated Repression of Tumor Necrosis Factor Alpha Translation Revealed through Use of cDNA Arrays
2003
Based on evidence that the von Hippel-Lindau (VHL) tumor suppressor protein is associated with polysomes and interacts with translation regulatory factors, we set out to investigate the potential influence of pVHL on protein translation. To this end, renal cell carcinoma (RCC) cells that either lacked pVHL or expressed pVHL through stable transfection were used to prepare RNA from cytosolic (unbound) and polysome-bound fractions. Hybridization of cDNA arrays using RNA from each fraction revealed a subset of transcripts whose abundance in polysomes decreased when pVHL function was restored. The tumor necrosis factor alpha (TNF-alpha) mRNA was identified as one of the transcripts that prefere…
Heavy metal ion induction of adhesion molecules and cytokines in human endothelial cells: the role of NF-kappaB, I kappaB-alpha and AP-1.
1997
We analyzed the influence of heavy-metal ions on human umbilical vein endothelial cells (HUVEC) in comparison to proinflammatory cytokines (TNF-alpha, IL-1beta) and lipopolysaccharide (LPS). Adhesion molecule and cytokine expressions are upregulated by heavy-metal exposure. Expression of E-selectin on the cell surface was strongly induced by 1-mM concentrations of NiCl2 and CoCl2, whereas ZnCl2 and CrCl3 had no influence. Furthermore, it is shown that NiCl2 induces mRNA expression of E-selectin, intercellular adhesion molecule-1, IL-6 and IL-8 in a 1-mM concentration. The transcription factor NF-kappaB is known to be involved in the regulation of adhesion molecule expression in endothelial …
Analysis of the Biological Response of Endothelial and Fibroblast Cells Cultured on Synthetic Scaffolds with Various Hydrophilic/Hydrophobic Ratios: …
2009
In this study we developed polymer scaffolds intended as anchorage rings for cornea prostheses among other applications, and examined their cell compatibility. In particular, a series of interconnected porous polymer scaffolds with pore sizes from 80 to 110 microns were manufactured varying the ratio of hydrophobic to hydrophilic monomeric units along the polymer chains. Further, the effects of fibronectin precoating, a physiological adhesion molecule, were tested. The interactions between the normal human fibroblast cell line MRC-5 and primary human umbilical vein endothelial cells (HUVECs) with the scaffold surfaces were evaluated. Adhesion and growth of the cells was examined by confocal…
Differential roles of PKCα and PKCɛ in controlling the gene expression of Nox4 in human endothelial cells
2007
NADPH oxidases are major sources of superoxide in the vascular wall. This study investigates the role of protein kinase C (PKC) in regulating gene expression of NADPH oxidases. Treatment of human umbilical vein endothelial cells (HUVEC) and HUVEC-derived EA.hy 926 endothelial cells with phorbol 12-myristate 13-acetate (PMA) or phorbol 12,13-dibutyrate led to a PKC-dependent biphasic expression of the gp91phox homolog Nox4. A downregulation of Nox4 was observed at 6 h and an upregulation at 48 h after phorbol ester treatment. The early Nox4 downregulation was associated with a reduced superoxide production, whereas the late Nox4 upregulation was accompanied by a clear enhancement of superoxi…
Activation of protein kinase C alpha and/or epsilon enhances transcription of the human endothelial nitric oxide synthase gene.
1998
In primary human umbilical vein endothelial cells (HUVECs), incubation with phorbol-12-myristate-13-acetate (PMA) enhanced basal and bradykinin-stimulated nitric oxide production. In the HUVEC-derived cell line EA.hy 926, PMA and phorbol-12,13-dibutyrate stimulated endothelial nitric oxide synthase (NOS III) mRNA expression in a concentration- and time-dependent manner. Maximal mRNA expression (3.3-fold increase) was observed after 18 hr. NOS III protein and activity were increased to a similar extent. The specific protein kinase C (PKC) inhibitors bisindolylmaleimide I (1 microM), Gö 6976 [12-(2 cyanoethyl)-6,7,12, 13-tetrahydro-13-methyl-5-oxo-5H-indolo[2,3-a]pyrrolo-[3, 4-c]carbazole] (1…
5’ tRNA halves are highly expressed in the primate hippocampus and sequence-specifically regulate gene expression
2019
AbstractFragments of mature tRNAs have long been considered as mere degradation products without physiological function. However, recent reports show that tRNA fragments (tRFs) play prominent roles in diverse cellular processes across a wide spectrum of species. Contrasting the situation in other small RNA pathways the mechanisms behind these effects appear more diverse, more complex and are generally less well understood. In addition, surprisingly little is known about the expression profiles of tRFs across different tissues and species. Here, we provide an initial overview of tRF expression in different species and tissues, revealing very high tRF-levels particularly in the primate hippoc…
Organization and expression of the chum salmon insulin-like growth factor II gene
1997
AbstractIGF-II plays an important role in growth and development of vertebrates. In the present study, the characterization of the first fish IGF-II gene, chum salmon IGF-II, is described. The sIGF-II gene consists of four exons, spanning a region of 9 kbp, that encode the 214 aa IGF-II precursor. While the amino acid sequences of fully processed IGF-II of salmon and mammalian species are very similar, the prepro-peptide sequence deviates extensively in the signal- and E-peptide domains. The transcription initiation site of the sIGF-II gene was localized within a 30 nt region employing RT-PCR. Using sIGF-II promoter-luciferase constructs it was demonstrated that the sIGF-II gene has a relat…
Post-transcriptional regulation of the human inducible nitric oxide synthase (iNOS) expression by the cytosolic poly(A)-binding protein (PABP).
2012
Affinity purification using the 3'-untranslated region (3'-UTR) of the human inducible nitric oxide synthase (iNOS) mRNA identified the cytosolic poly(A)-binding protein (PABP) as a protein interacting with the human iNOS 3'-UTR. Downregulation of PABP expression by RNA interference resulted in a marked reduction of cytokine-induced iNOS mRNA expression without changes in the expression of mRNAs coding for the major subunit of the RNA polymerase II (Pol 2A) or β2-microglobuline (β2M). Along with the mRNA also iNOS protein expression was reduced by siPABP-treatment, whereas in the same cells protein expression of STAT-1α, NF-κB p65, or GAPDH was not altered. Reporter gene analyses showed no …
The Cth2 ARE-binding protein recruits the Dhh1 helicase to promote the decay of succinate dehydrogenase SDH4 mRNA in response to iron deficiency
2008
Iron is an essential nutrient that participates as a redox co-factor in a broad range of cellular processes. In response to iron deficiency, the budding yeast Saccharomyces cerevisiae induces the expression of the Cth1 and Cth2 mRNA-binding proteins to promote a genome-wide remodeling of cellular metabolism that contributes to the optimal utilization of iron. Cth1 and Cth2 proteins bind to specific AU-rich elements within the 3'-untranslated region of many mRNAs encoding proteins involved in iron-dependent pathways, thereby promoting their degradation. Here, we show that the DEAD box Dhh1 helicase plays a crucial role in the mechanism of Cth2-mediated mRNA turnover. Yeast two-hybrid experim…