RESUMO
This study focuses on the protective effect of germacrone on human umbilical vein endothelial cells(HUVECs) damaged by H2O2-induced oxidative stress and its possible mechanisms. The oxidative damage model was established by using 500 μmol•L⁻¹ H2O2 to treat HUVECs for 3 hours, and then protected with different concentrations of germacrone for 24 hours. The effect of germacrone on cell viability of HUVECs damaged by H2O2 was detected by MTT. The contents of PGI2, TXB2, ET-1, t-PA, PAI-1, TNF-α and IL-6 were detected by ELISA. The content of NO was detected by using nitrate reductase method. Colorimetry was used to detect NOS and GSH-Px. The contents of MDA, SOD and LDH were detected by TBA, WST-1 and microplate respectively. Apoptosis was observed by Hoechst 33258 fluorescent staining. The mRNA expressions of Bax, Bcl-2 and Caspase-3 in cells were detected by RT-PCR. The results showed that the cell damage rate was 52% after treated with 500 μmol•L⁻¹ H2O2 for 3 hours. The cell activity was increasing with the rise of germacrone concentration within the range of 20-200 mol•L⁻¹. Compared with normal group, the contents of PGI2, NO, T-NOS, t-PA, SOD, GSH-Px and Bcl-2 mRNA expressions were lower after damaged with H2O2. The contents of PAI-1, ET-1, IL-6, TNF-α, TXB2, LDH, MDA, Bax mRNA and Caspase-3 mRNA expressions were increased. Compared with model group, the contents of PGI2, NO, T-NOS, t-PA, SOD, GSH-Px and Bcl-2 mRNA expressions were increased after treated with germacrone. The contents of PAI-1, ET-1, IL-6, TNF-α, TXB2, LDH, MDA, Bax mRNA and Caspase-3 mRNA expressions were lower after treated with germacrone. According to Hoechst 33258 fluorescence staining, compared with normal group, the cell membrane and the nucleus showed strong dense blue fluorescence, and the number of cells significantly decreased in model group. Compared with model group, blue fluorescence intensity decreased in drug group. The above findings demonstrate that germacrone may improve the effect on HUVECs damaged by H2O2-induced oxidative stress by resisting oxidation and inhibiting cell apoptosis.
RESUMO
Ubiquitin is highly conserved 76 amino acid protein found in all eukaryotic organisms and ubiquitin-proteasome pathway (UPP) plays a very important role in regulated non-lysosomal ATP dependent protein degradation. This pathway participates in or regulates numerous cellular processes, such as selective protein degradation, cell cycle progression, apoptosis, signal transduction, transcriptional regulation, receptor control by endocytosis, immune response and the processing of antigens. Nevertheless, roles of UPP in virus infection are only beginning to be clarified. Ubiquitin homology has also been found in insect viruses. All viral ubiquitin genes encode an N-terminal ubiquitin sequence and 3-256 amino acids C-terminal peptides. Most of the residues known to be essential for ubiquitin function have been conserved in the viral variant. In Autographa californica nucleopolyhedrovirus (AcMNPV), viral ubiquitin is attached to the inner surface of budded viron membrane by a covalently linked phospholipid and is not essential for viral replication. Currently, insect viruses are the only viruses known to encode ubiquitin. However, ubiquitin also plays a role in the life cycle of other viruses. Host ubiquitin molecules have been found in some plant viruses and other animal viruses. Additionally, Africa swine fever virus (ASFV) encodes a ubiquitin-conjugating enzyme (E2) and a putative causal link between human immunodeficiency virus type 1 (HIV-1) and ubiquitin was established by showing that depletion of the intracellular pool of free ubiquitin inhibits the virus budding. Further analyses indicated that many retroviruses proteins which are required for efficient pinching off the virus bud contain a late domain. The core element of the late domain is a proline-rich motif (PPXY) which mediates the late domain to be ubiquitinated by cellular proteins. Recently, it has been shown that many retroviruses have developed mechanisms to escape the cellular immune response, to facilitate virus replication and to promote virus assembly and budding via host UPP.