Protein glutathionylation is a posttranslational modification of cysteine residues with glutathione in response to mild oxidative stress. Because 15-deoxy-Δ12,14-prostaglandin J(2) (15d-PGJ(2)) is an electrophilic prostaglandin that can increase glutathione (GSH) levels and augment reactive oxygen species (ROS) production, we hypothesized that it induces NF-κB-p65 glutathionylation and would exert anti-inflammatory effects. Herein, we show that 15d-PGJ(2) suppresses the expression of ICAM-1 and NF-κB-p65 nuclear translocation. 15d-PGJ(2) upregulates the Nrf2-related glutathione synthase gene and thereby increases the GSH levels. Consistent with this, Nrf2 siRNA molecules abolish the inhibition of p65 nuclear translocation in 15d-PGJ(2)-induced endothelial cells (ECs). ECs treated with GSSG show increased thiol modifications of p65 and also a block in TNFα-induced p65 nuclear translocation and ICAM-1 expression, but not in IκBα degradation. However, the overexpression of glutaredoxin 1 was found to be accompanied by a modest increase in NF-κB activity. Furthermore, we found that multiple cysteine residues in p65 are responsible for glutathionylation. 15d-PGJ(2) was observed to induce p65 glutathionylation and is suppressed by a GSH synthesis inhibitor, buthionine sulfoximine, by catalase, and by Nrf2 siRNA molecules. Our results thus indicate that the GSH/ROS-dependent glutathionylation of p65 is likely to be responsible for 15d-PGJ(2)-mediated NF-κB inactivation and for the enhanced inhibitory effects of 15d-PGJ(2) on TNFα-treated ECs. 相似文献
Ten azo compounds including azo-resveratrol (5) and azo-oxyresveratrol (9) were synthesized using a modified Curtius rearrangement and diazotization followed by coupling reactions with various phenolic analogs. All synthesized compounds were evaluated for their mushroom tyrosinase inhibitory activity. Compounds 4 and 5 exhibited high tyrosinase inhibitory activity (56.25% and 72.75% at 50 μM, respectively). The results of mushroom tyrosinase inhibition assays indicate that the 4-hydroxyphenyl moiety is essential for high inhibition and that 3,5-dihydroxyphenyl and 3,5-dimethoxyphenyl derivatives are better for tyrosinase inhibition than 2,5-dimethoxyphenyl derivatives. Particularly, introduction of hydroxyl or methoxy group into the 4-hydroxyphenyl moiety diminished or significantly reduced mushroom tryosinase inhibition. Among the synthesized azo compounds, azo-resveratrol (5) showed the most potent mushroom tyrosinase inhibition with an IC50 value of IC50 = 36.28 ± 0.72 μM, comparable to that of resveratrol, a well-known tyrosinase inhibitor. 相似文献
Macroautophagy/autophagy is a central mechanism by which cells maintain integrity and homeostasis, and endotoxin-induced autophagy plays important roles in innate immunity. Although TLR4 stimulation mediated by lipopolysaccharide (LPS) also upregulates autophagy in hepatocytes and liver, its physiological role remains elusive. The objective of this study was to determine the role of LPS-induced autophagy in the regulation of liver lipid metabolism. LPS treatment (5 mg/kg) increased autophagy, as detected by LC3 conversion and transmission electron microscopy (TEM) analysis in C57BL6 mouse livers. AC2F hepatocytes also showed increased autophagic flux after LPS treatment (1 μg/ml). To investigate the role of LPS-induced autophagy further, liver lipid metabolism changes in LPS-treated mice and fasted controls were compared. Interestingly, LPS-treated mice showed less lipid accumulation in liver than fasted mice despite increased fatty acid uptake and lipid synthesis-associated genes. In vitro analysis using AC2F hepatocytes demonstrated LPS-induced autophagy influenced the degradation of lipid droplets. Inhibition of LPS-induced autophagy using bafilomycin A1 or Atg7 knockdown significantly increased lipid accumulation in AC2F hepatocytes. In addition, pretreatment with chloroquine aggravated LPS-induced lipid accumulation and inflammation in C57BL6 mouse livers. The physiological importance of autophagy was verified in LPS-treated young and aged rats. Autophagic response was diminished in LPS-treated aged rats and lipid metabolism was impaired during sepsis, indicating autophagy response is important for regulating lipid metabolism after endotoxin challenge. Our findings demonstrate endotoxin-induced autophagy is important for the regulation of lipid metabolism, and suggest that autophagy helps maintain lipid metabolism homeostasis during sepsis. 相似文献
Hollow fibre membrane bioreactors (HFB) provide a novel approach towards tissue engineering applications in the field of regenerative medicine. For adherent cell types, HFBs offer an in vivo-like microenvironment as each fibre replicates a blood capillary and the mass transfer rate across the wall is independent from the shear stresses experienced by the cell. HFB also possesses the highest surface area to volume ratio of all bioreactor configurations. In theory, these factors enable a high quantity of the desired cellular product with less population variation, and favourable operating costs. Experimental analyses of different cell types and bioreactor designs show encouraging steps towards producing a clinically relevant device. This review discusses the basic HFB design for cell expansion and in vitro models; compares data produced on commercially available systems and addresses the operational differences between theory and practice. HFBs are showing some potential for mammalian cell culture but further work is needed to fully understand the complexities of cell culture in HFBs and how best to achieve the high theoretical cell yields. 相似文献
A marine, facultatively anaerobic, nitrogen-fixing bacterium, designated strain DNF-1T, was isolated from the lagoon sediment of Dongsha Island, Taiwan. Cells grown in broth cultures were Gram-negative rods that were motile by means of monotrichous flagella. Cells grown on plate medium produced prosthecae and vesicle-like structures. NaCl was required and optimal growth occurred at about 2–3% NaCl, 25–30 °C and pH 7–8. The strain grew aerobically and was capable of anaerobic growth by fermenting D-glucose or other carbohydrates as substrate. Both the aerobic and anaerobic growth could be achieved with NH4Cl as a sole nitrogen source. When N2 served as the sole nitrogen source only anaerobic growth was observed. Major cellular fatty acids were C14:0, C16:0 and C16:1ω7c, while major polar lipids were phosphatidylethanolamine and phosphatidylglycerol. The DNA G+C content was 42.2 mol% based on the genomic DNA data. Phylogenetic analyses based on 16S rRNA genes and the housekeeping genes, gapA, pyrH, recA and gyrB, revealed that the strain formed a distinct lineage at species level in the genus Vibrio of the family Vibrionaceae. These results and those from genomic, chemotaxonomic and physiological studies strongly support the assignment of a novel Vibrio species. The name Vibrio salinus sp. nov. is proposed for the novel species, with DNF-1T (=?BCRC 81209T?=?JCM 33626T) as the type strain. This newly proposed species represents the second example of the genus Vibrio that has been demonstrated to be capable of anaerobic growth by fixing N2 as the sole nitrogen source.
Crk-associated substrate (Cas) is highly phosphorylated by v-Src and plays a critical role in v-Src-induced cell transformation. In this study, we found that the Src homology (SH) 3 domain of Cas blocked v-Src-stimulated anchorage-independent cell growth, Matrigel invasion, and tumor growth in nude mice. Biochemical analysis revealed that the Cas SH3 domain selectively inhibited v-Src-stimulated activations of AKT and JNK, but not ERK and STAT3. Attenuation of the AKT pathway by the Cas SH3 domain rendered v-Src-transformed cells susceptible to apoptosis. Inhibition of the JNK pathway by the Cas SH3 domain led to suppression of v-Src-stimulated invasion. Taken together, our results indicate that the Cas SH3 domain has an anti-tumor function, which severely impairs the transforming potential of v-Src. 相似文献