RESUMEN
Lysine acetylation has emerged as one of the most important post-translational modifications that participates in various biological and pathological processes. Histone acetyltransferase 1 (HAT1) as the first identified protein ε-amino lysine acetyltransferase is able to regulate the acetylation of histones and non-histone proteins. However‚ the acetylation substrates and sites mediated by HAT1 in liver cancer are poorly understood. In this study‚ we demonstrated that HAT1 was highly expressed in the liver cancer tissues‚ which was negatively associated with the prognosis of patients. Based on the establishment of the HAT1-knockout HepG2 cell line‚ we employed a quantitative proteomics approach to study the profiling of acetylation mediated by HAT1 in HepG2 cells. Interestingly‚ we identified a total of 858 Kac sites on 547 proteins in the HepG2 cell line‚ in which HAT1 mediated the levels of Kac of 74 sites on 68 proteins. The pathways and metabolic processes that were affected by HAT1-dependent acetylation modification were analyzed by bioinformatics. The results show that Kac regulates disease development‚ RNA biology‚ spliceosome and nucleosome assembly‚ oxidative stress‚ various signaling pathways and metabolic pathways‚ etc.. Moreover‚ we verified that the HAT1-mediated acetylation modification could promote abnormal lipid metabolism. CCK8 assays‚ clone formation and Edu assays revealed that HAT1 could remarkably enhance the cell proliferation of liver cancer in vitro. Thus‚ our finding explored the profiling of HAT1-mediated protein acetylation in HepG2 cells‚ which provides new insights into the underlying mechanism by which HAT1 mediates the development of liver cancer. Clinically‚ the HAT1-mediated acetylation sites could be used for the precise targets of drug development.
RESUMEN
Reversible post-translational modification of proteins is an important process in the physiological regulation of all tissues, including the heart. Lysine acetylation occurs in all organisms, including prokaryotes, and is regulated by a balance between lysine acetyltransferase (adding acetyl to the ε-amino group of lysine) and deacetylase (acetyl group that removes lysine ε-amino group). The heart is an organ rich in acetylated lysine, but the role of acetylated lysine in the heart remains to be elucidated. Therefore, in this paper, we systematically reviewed the gene list of acetyltransferase and deacetylase in mammalian genome and indicated their mRNA expression. The purpose of this study is to discover the research progress of dynamic regulation of lysine acetylation in heart disease and to provide a theoretical basis for the discovery of molecular targets.
RESUMEN
Flavonoids are polyphenol compounds abundantly found in plants and reported to have an inhibitory effect on amyloidfibrillation. The number and position of hydroxyl groups, as well as the arrangement of flavonoids rings, may influencetheir inhibitory effects. In this study, we investigate the effect of structural characteristics of flavonoids on amyloid fibrilformation. For this purpose, five compounds (i.e., biochanin A, daidzein, quercetin, chrysin and fisetin) were selected thatrepresent a variety in the number and position of their hydroxyl groups. The inhibitory effect of these flavonoids on theamyloid fibril formation of apo-carbonic anhydrase (apo-BCA), as a model protein, was evaluated using thioflavin T andtransmission electron microscopy. The results showed that fisetin possessed the most significant inhibitory effect. Interestingly, upon apo-BCA acetylation, none of the tested flavonoids could inhibit the fibrillation process, which indicates thatthe interactions of these compounds with the amine groups of lysine residues could be somewhat important
RESUMEN
Enhanced oxidative stress is a hallmark of cisplatin nephrotoxicity, and inhibition of poly(ADP-ribose) polymerase 1 (PARP1) attenuates oxidative stress during cisplatin nephrotoxicity; however, the precise mechanisms behind its action remain elusive. Here, using an in vitro model of cisplatin-induced injury to human kidney proximal tubular cells, we demonstrated that the protective effect of PARP1 inhibition on oxidative stress is associated with sirtuin 3 (SIRT3) activation. Exposure to 400 µM cisplatin for 8 hours in cells decreased activity and expression of manganese superoxide dismutase (MnSOD), catalase, glutathione peroxidase (GPX), and SIRT3, while it increased their lysine acetylation. However, treatment with 1 µM PJ34 hydrochloride, a potent PARP1 inhibitor, restored activity and/or expression in those antioxidant enzymes, decreased lysine acetylation of those enzymes, and improved SIRT3 expression and activity in the cisplatin-injured cells. Using transfection with SIRT3 double nickase plasmids, SIRT3-deficient cells given cisplatin did not show the ameliorable effect of PARP1 inhibition on lysine acetylation and activity of antioxidant enzymes, including MnSOD, catalase and GPX. Furthermore, SIRT3 deficiency in cisplatin-injured cells prevented PARP1 inhibition-induced increase in forkhead box O3a transcriptional activity, and upregulation of MnSOD and catalase. Finally, loss of SIRT3 in cisplatin-exposed cells removed the protective effect of PARP1 inhibition against oxidative stress, represented by the concentration of lipid hydroperoxide and 8-hydroxy-2'-deoxyguanosine; and necrotic cell death represented by a percentage of propidium iodide–positively stained cells. Taken together, these results indicate that PARP1 inhibition protects kidney proximal tubular cells against oxidative stress through SIRT3 activation during cisplatin nephrotoxicity.