Search results for "acetylation"
showing 10 items of 140 documents
New Acylated Triterpene Saponins from Silene fortunei that Modulate Lymphocyte Proliferation
2002
Three new acylated triterpene saponins 1-3, with a quillaic acid as aglycon, were isolated from the roots of Silene fortunei together with a known phytoecdysteroid (20-hydroxyecdysone). The compounds were characterized mainly by a combination of 2D NMR techniques, mass spectrometry, and chemical methods. Saponins 1-3, jenisseensosides C and D (4, 5), and 6 (deacylated form of 2/3 and 4/5) were found to stimulate the proliferation of the Jurkat tumor cell lines at low concentration. At high concentration, 2/3 and 4/5 inhibited the proliferation of the cells and suggested the induction of apoptosis.
Regulation of the p19(Arf)/p53 pathway by histone acetylation underlies neural stem cell behavior in senescence-prone SAMP8 mice.
2015
Brain aging is associated with increased neurodegeneration and reduced neurogenesis. B1/neural stem cells (B1-NSCs) of the mouse subependymal zone (SEZ) support the ongoing production of olfactory bulb interneurons, but their neurogenic potential is progressively reduced as mice age. Although age-related changes in B1-NSCs may result from increased expression of tumor suppressor proteins, accumulation of DNA damage, metabolic alterations, and microenvironmental or systemic changes, the ultimate causes remain unclear. Senescence-accelerated-prone mice (SAMP8) relative to senescence-accelerated-resistant mice (SAMR1) exhibit signs of hastened senescence and can be used as a model for the stud…
PCAF catalyzes tha acetylation of spermidine to N8-acetylspermidine and regulates its acetylating activity on histones
2011
Post-transcriptional histone acetylation is a well known process playing a crucial role in chromatin assembly and transcription. Here, we report that PCAF, a highly conserved histone acetyltransferase (HAT), can efficiently catalyze acetylation of spermidine to N8-acetylspermidine, at low concentration. Remarkably, we found that spermidine at higher concentration can also inhibit PCAF HAT activity directed against histone H3 in vitro, confirming the in vivo data referred by Eisenberg et al. on the spermidine induced inhibition of H3 acetylation. Surprisingly when we performed HAT assay experiments at low spermidine concentration we observed an activating effect on PCAF on H3 acetylation. Ou…
Enhancement of lysine acetylation accelerates wound repair
2013
In physiopathological conditions, such as diabetes, wound healing is significantly compromised and chronic complications, including ulcers, may occur. In a mouse model of skin repair, we recently reported that wound treatment with Sirtuin activators and class I HDAC inhibitors induced keratinocyte proliferation and enhanced healing via a nitric oxide (NO) dependent mechanism. We observed an increase in total protein acetylation in the wound area, as determined by acetylation of α-tubulin and histone H3 Lysine 9. We reasoned that this process activated cell function as well as regulated gene expression to foster tissue repair. We report here that the direct activation of P300/CBP-associated …
Guanaconetins, new antitumoral acetogenins, mitochondrial complex I and tumor cell growth inhibitors
2005
The antitumoral activity of a series of acetylated bis-tetrahydrofuranic acetogenins with a threo/trans/threo/trans/erythro relative configuration was characterized by four new natural and two semisynthetic, 15,24,30-trioxygenated acetogenins that were found to inhibit mitochondrial complex I enzyme as well as growth of several tumor cell lines. Placement of acetyl groups along the alkyl chain modulated the potency of the bis-tetrahydrofuranic acetogenins and could be important for future utilization of these compounds as chemotherapeutic agents.
Synthesis, chemical characterization and biological activity of new histone acetylation/deacetylation specific inhibitors: a novel and potential appr…
2013
Three new triorganotin(IV) complexes of valproic acid (vp1, Me3Sn-valproate; vp2, Bu3Sn-valproate; vp3, Ph3Sn-valproate) have been synthesized and investigated by spectroscopic and biological methods. An anionic, monodentate valproate ligand was observed, ester-like coordinating the tin atom on a tetra-coordinated, monomeric environment. The structures, though, can distort towards a penta-coordination, as a consequence of a long range O center dot center dot center dot Sn interaction. Crystallographic and NMR findings confirm this situation both in solid state and solution. Biological finding evidenced a clear cytotoxic action of the complexes in hepatocellular carcinoma cell cultures: one …
Zur Acetylierung von Spironolacton, Canrenon und 2-Methylencanrenon
1995
Bei der Umsetzung der Titelverbindungen mit Acetanhydrid und Acetylchlorid werden das 3,5-Dien-3-yl-acetat 2, die isomeren 2,4,6- und 3,5,7-Trien-3-yl-acetate 3 und 4 sowie das 2,4,6,8(14)-Tetraen-3-yl-acetat 7 erhalten. Hydrolyse von 7 liefert das 2α-Methl-8,14-didehydro-canrenon (9). 7 und 9 wurden auf ihre Bindungsfahigkeit gegenuber Hormon-Rezeptoren sowie den Serumproteinen SHBG und CBG gepruft: Die Substanzen erwiesen sich als inaktiv. Acetylation of Spironolactone, Canrenone, and 2-Methylene Canrenone Reaction of the title compounds with acetic anhydride and acetyl chloride yields the 3,5-dien-3-yl acetate 2 the isomeric 2,4,6- and 3,5,7-trien-3-yl acetates 3 and 4 as well as the 2,4…
Lifelong exposure to low dose xeno-hormones in rats : multi-generational effects of xeno-hormone mixtures on taste preferences, maternal behavior, an…
2012
During the last decade, the issue of health-related endocrine disruptors (ED) has been extended to the toxicity of mixtures. The objective of this study was to define the effects of lifelong exposure to ED mixtures, at low doses defined as "non-harmful" by the authorities. In this aim, the effects of mixtures combining genistein, vinclozolin and bisphenol A, have been investigated in the rat by using an integrative and multi-generational experimental approach which takes into account maternal behavior, feeding behavior and development. Our results show that these mixtures could: a) reduce maternal behavior, b) change taste preferences (sweet, salty), c) affect the development from the in ut…
Epigenetic Regulation of Early- and Late-Response Genes in Acute Pancreatitis
2015
Abstract Chromatin remodeling seems to regulate the patterns of proinflammatory genes. Our aim was to provide new insights into the epigenetic mechanisms that control transcriptional activation of early- and late-response genes in initiation and development of severe acute pancreatitis as a model of acute inflammation. Chromatin changes were studied by chromatin immunoprecipitation analysis, nucleosome positioning, and determination of histone modifications in promoters of proinflammatory genes in vivo in the course of taurocholate-induced necrotizing pancreatitis in rats and in vitro in rat pancreatic AR42J acinar cells stimulated with taurocholate or TNF-α. Here we show that the upregulat…
The histone deacetylase Rpd3 regulates the heterochromatin structure of Drosophila telomeres
2011
Telomeres are specialized structures at the end of eukaryotic chromosomes that are required to preserve genome integrity, chromosome stability and nuclear architecture. Telomere maintenance and function are established epigenetically in several eukaryotes. However, the exact chromatin enzymatic modifications regulating telomere homeostasis are poorly understood. In Drosophila melanogaster, telomere length and stability are maintained through the retrotransposition of specialized telomeric sequences and by the specific loading of protecting capping proteins, respectively. Here, we show that the loss of the essential and evolutionarily conserved histone deacetylase Rpd3, the homolog of mammal…