5 research outputs found
Resveratrol prevents nanoparticles-induced inflammation and oxidative stress via downregulation of PKC-α and NADPH oxidase in lung epithelial A549 cells
Abstract Background Exposure to carbon black nanoparticles (CBNPs), a well-known industrial production, promotes pulmonary toxicity through inflammation and oxidative stress. Recent studies show that some polyphenols exert their antioxidant properties through regulation of protein kinase C-α (PKC-α) and NADPH oxidase (Nox) signaling. Resveratrol, a dietary polyphenol in fruits, possesses various health beneficial effects including anti-inflammatory and antioxidative properties. In this study, we aimed to elucidate the involvement of PKC-α and Nox in CBNPs-induced inflammation and oxidative stress, and to investigate the protective effects of resveratrol on CBNP-induced inflammation and oxidative stress in human lung epithelial A549 cells. Methods The production of reactive oxygen species (ROS) and the change of mitochondrial membrane potential (ΔΨm) were measured by flow cytometry. Nitric oxide (NO) was measured using the Griess reagent, and prostaglandin E2 (PGE2) production was detected by ELISA, while protein expressions were measured by Western blotting analysis. Results In lung epithelial A549 cells, CBNPs significantly enhanced oxidative stress by upregulation of Nox2 and membrane expression of p67phox accompanied with increase of ROS production. CBNPs also increased inflammatory factors, including iNOS, COX-2, NO and PGE2. However, resveratrol attenuated the above effects induced by CBNPs in A549 cells; additionally, CBNPs-induced activation of PKC-α was observed. We found that PKC-α inhibitor (Gö6976) could attenuate CBNPs-induced inflammation by down-regulation of ROS, NO and PGE2 production in A549 cells, suggesting PKC-α might be involved in CBNPs-induced oxidative stress and inflammation. Our results also found resveratrol was able to inhibit protein expression of PKC-α induced by CBNPs. Moreover, ROS scavenger (NAC) and Nox inhibitor (DPI) attenuated CBNPs-induced expressions of iNOS and COX-2. DPI could also attenuate CBNPs-induced ROS, NO and PGE2 production. Conclusions Resveratrol attenuated CBNPs-induced oxidative and inflammatory factors in lung epithelial A549 cells, at least in part via inhibiting PKC-α- and Nox-related signaling
Effect of Charged Amino Acid Side Chain Length at Non-Hydrogen Bonded Strand Positions on β‑Hairpin Stability
β-Sheets
have been implicated in various neurological disorders,
and ∼20% of protein residues adopt a sheet conformation. Therefore,
studies on the structural origin of sheet stability can provide fundamental
knowledge with potential biomedical applications. Oppositely charged
amino acids are frequently observed across one another in antiparallel
β-sheets. Interestingly, the side chains of natural charged
amino acids Asp, Glu, Arg, Lys have different numbers of hydrophobic
methylenes linking the backbone to the hydrophilic charged functionalities.
To explore the inherent effect of charged amino acid side chain length
on antiparallel sheets, the stability of a designed hairpin motif
containing charged amino acids with varying side chain lengths at
non-hydrogen bonded positions was studied. Peptides with the guest
position on the N-terminal strand and the C-terminal strand were investigated
by NMR methods. The charged amino acids (Xaa) included negatively
charged residues with a carboxylate group (Asp, Glu, Aad in increasing
length), positively charged residues with an ammonium group (Dap,
Dab, Orn, Lys in increasing length), and positively charged residues
with a guanidinium group (Agp, Agb, Arg, Agh in increasing length).
The fraction folded and folding free energy for each peptide were
derived from the chemical shift deviation data. The stability of the
peptides with the charged residues at the N-terminal guest position
followed the trends: Asp > Glu > Aad, Dap < Dab < Orn
∼
Lys, and Agb < Arg < Agh < Agp. The stability of the peptides
with the charged residues at the C-terminal guest position followed
the trends: Asp < Glu < Aad, Dap ∼ Dab < Orn ∼
Lys, and Agb < Arg ∼ Agp < Agh. These trends were rationalized
by thermodynamic sheet propensity and cross-strand interactions