Protective effects of α-lipoic acid on cultured human nasal fibroblasts exposed to urban particulate matter

Overexpression of Lias Gene Alleviates Cadmium-Induced Kidney Injury in Mice Involving Multiple Effects: Metabolism, Oxidative Stress, and Inflammation

Oxidative stress is an important mechanism underlying toxicity induced by cadmium (Cd) exposure. However, there are significant differences of the antioxidant baseline in different populations. This means that different human has different intensity of oxidative stress in vivo after exposure to toxicants. LiasH/H mouse is a specific model which is created by genetically modifying the Lias 3'-untranslated region (3'-UTR). LiasH/H mice express high levels of LA and have high endogenous antioxidant capacity which is approximately 150% higher than wild-type C57BL/6 J mice (WT, Lias+/+). But more importantly, they have dual roles of metal chelator and antioxidant. Here, we applied this mouse model to evaluate the effect of endogenous antioxidant levels in the body on alleviating Cd-induced renal injury including Cd metabolism, oxidative stress, and inflammation. In the experiment, mice drank water containing Cd (50 mg/L), for 12 weeks. Many biomarkers of Cd metabolism, oxidative stress, inflammation, and major pathological changes in the kidney were examined. The results showed overexpression of the Lias gene decreased Cd burden in the body of mice, mitigated oxidative stress, attenuated the inflammatory response, and subsequent alleviated cadmium-induced kidney injury in mice.

The potential cytotoxic effects of urban particle matter on olfaction

BACKGROUND

Urban particulate matter (UPM) in ambient air is implicated in a variety of human health issues worldwide, however, few studies exist on the effect of UPM on the olfactory system. This study aimed to identify the factors affecting the destruction of the olfactory system in a mouse model following UPM exposure.

METHODS

Mice were divided into: control and four UPM-exposed groups (200 µg UPM at 1 and 2 weeks, and 400 µg UPM at 1 and 2 weeks [standard reference material 1649b; average particle diameter 10.5 μm]). The olfactory neuroepithelium was harvested for histologic examination, gene ontology, quantitative real-time polymerase chain reaction, and western blotting.

RESULTS

Compared to the control group, olfactory marker protein, Olfr1507, ADCY3, and GNAL mRNA levels were lower, and S-100, CNPase, NGFRAP1, BDNF, and TACR3 mRNA levels were higher in the olfactory neuroepithelium of the UPM groups. Moderately positive correlation was present between the 1- and 2-week groups. After analyzing the 200 and 400 UPM groups separately, the strength of the association between the 200 UPM 1- and 2-week groups was moderately positive. No differences was present in the neuroepithelial inflammatory marker levels between the UPM and control groups.

CONCLUSIONS

UPM could have cytotoxic effects on the olfactory epithelium. The exposure time and particular concentration of UPM exposure could affect the degree of destruction of the olfactory neuroepithelium. The olfactory regeneration mechanism could be related to the neurotrophic factors, olfactory ensheathing cell stimulation, and trigeminal nerve support.

Effects of Urban Particulate Matter on the Olfactory System in a Mouse Model

BACKGROUND

Exposure to urban particulate matter (UPM) is linked to the aggravation of various health problems. Although the nasal cavity is the first barrier to encounter UPM, there is a lack of studies on the impact of UPM on the olfactory area. The purpose of this study was to investigate the cytotoxic effects of UPM on mouse olfactory epithelium, the underlying pathophysiology involved, and changes in cytokine levels.

METHODS

Mice were divided into 4 groups: control, 400UPM (administered 400 µg UPM daily; standard reference material 1649b; average particle diameter 10.5 μm) 1week, 400UPM 2weeks, and recovery 1week after 400UPM 2weeks (n = 10, 6, 6, and 6, respectively). Olfactory function was evaluated by conducting a food-finding test once a week. The olfactory neuroepithelium was harvested for histologic examination, gene ontology, quantitative real-time polymerase chain reaction, and western blotting.

RESULTS

Compared to those in the control group, olfactory marker protein, olfactory receptor 1507, adenylyl cyclase 3, and GNAL mRNA levels were lower and S-100, 2',3'-cyclic nucleotide 30-phosphodiesterase, nerve growth factor receptor-associated protein, brain-derived neurotrophic factor, and tachykinin receptor mRNA levels were higher in the 400UPM group olfactory neuroepithelium. There were no significant differences in neuroepithelial inflammatory marker levels between the 400UPM and saline group.

CONCLUSIONS

UPM decreased olfactory function and might have cytotoxic effects on the olfactory epithelium. Olfactory ensheathing cells and trigeminal nerve might be related to the regeneration of the olfactory epithelium after olfactory destruction associated with UPM.

Intratympanic administration of alpha-lipoic acid-loaded pluronic F-127 nanoparticles ameliorates acute hearing loss

We used antioxidant-containing nanoparticles (NPs) to treat acute hearing loss. Alpha-lipoic acid (ALA) served as the antioxidant; we employed Pluronic F127 to fabricate NPs. In vitro, ALA-NPs protected cells of the organ of Corti in HEI-OC1 mice, triggering nuclear translocation of NRF2 and increases in the levels of antioxidant proteins, including Nrf2, HO-1, SOD-1, and SOD-2. In vivo, the hearing of mice that received ALA-NP injections into the middle ear cavity was better preserved after induction of ototoxicity than in control animals. The cochlear Nrf2 level increased in test mice, indicating that the ALA-NPs protected hearing via the antioxidant mechanism observed in vitro. ALA-NPs effectively protected against acute hearing loss by activating the Nrf2/HO-1 pathway.

Urban particulate matter regulates tight junction proteins by inducing oxidative stress via the Akt signal pathway in human nasal epithelial cells

Recent studies have revealed that increased reactive oxidative stress (ROS) induced by particulate matter (PM) affects tight junction (TJ) functions; however, the molecular mechanisms underlying this effect have not been evaluated fully. Cultured human epithelial cells obtained from inferior turbinate tissues were exposed to an urban PM (UPM) standard reference material (SRM 1648a). Intracellular ROS level and expression of proinflammatory cytokines and TJ proteins were examined. Expression level of phosphorylated (p)-Akt, p38, p65 were compared between exposed and unexposed cells. Cells were pretreated with the ROS scavenger N-acetylcysteine (NAC) or Akt inhibitor MK-2206 before exposure to determine whether the changes in cellular ROS and TJ protein expression could be reversed. Exposure to UPM significantly increased ROS levels and inflammatory cytokine expression levels, and decreased expression of TJ proteins zonula occludins (ZO)-1, occludin, claudin-1, and E-cadherin. UPM exposure increased p-Akt, p-p38, and p65 expression levels, and NAC pretreatment reversed these effects. Akt inhibition decreased UPM-induced ROS formation and p38 and p65 protein phosphorylation, and restored the decreased ZO-1 and E-cadherin expression. Akt inhibition and ROS scavenging may provide targets for maintaining epithelial integrity by restoring decreased TJ protein expression during exposure to UPM.

Effect of fluticasone propionate on human nasal fibroblasts exposed to urban particulate matter

OBJECTIVE

Particulate matter (PM), which contains organic compounds and toxic metals, is the major cause of air pollution. PM enters the body, causing various health problems. Although the effects of PM on the lower respiratory tract have been extensively investigated, the effects on the upper respiratory tract (including the nasal cavity) require further evaluation. To investigate the effect of fluticasone propionate (FP) on nasal fibroblasts exposed to UPM.

METHODS

Samples of inferior turbinate tissue were obtained from six patients. The fibroblasts isolated from these samples were exposed to UPM and/or FP. The expression of interleukin (IL)-6, CXC chemokine ligand (CXCL) 1, IL-1β, and tumour necrosis factor-alpha (TNF-α) in nasal fibroblasts was analysed using real-time PCR and enzyme-linked immunosorbent assays. The protein levels of nuclear factor kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3) were analysed by western blotting.

RESULTS

FP reversed the UPM-induced reduction in cell viability. The mRNA and protein levels of IL-6, CXCL1, IL-1β, and TNF-α were significantly increased by UPM. FP reversed the UPM-induced increases in the protein levels of NF-κB and phosphorylated-STAT3 in a dose-dependent manner. In addition, TNF-α, an inducer of NF-κB, reversed the FP-induced reduction in the levels of signalling molecules.

CONCLUSION

UPM induces the expression of IL-6, CXCL1, IL-1β, and TNF-α in nasal fibroblasts and this effect is reversed by FP via the STAT3 and NF-κB signalling pathways. These results suggest that FP has therapeutic potential for nasal diseases related to UPM, such as allergic and chronic rhinitis.

Activation of the Nrf2/HO-1 pathway by curcumin inhibits oxidative stress in human nasal fibroblasts exposed to urban particulate matter

BACKGROUND

Particulate matter (PM) can cause various negative acute and chronic diseases of the respiratory system, including the upper airways. Curcumin has been reported to have anti-inflammatory and anti-oxidative effects; therefore, we investigated the effects of curcumin on nasal fibroblasts exposed to urban PM (UPM).

METHODS

Samples of inferior turbinate tissue were obtained from six patients. Flow cytometry was used to assess the levels of reactive oxygen species (ROS) following the treatment of nasal fibroblasts with UPM and/or curcumin. We evaluated the effects of UPM and/or curcumin on the expression of phosphorylated ERK, Nrf2, HO-1, and SOD2 in fibroblasts by Western blotting.

RESULTS

When UPM was applied to nasal fibroblasts, ROS production was significantly increased in a dose-dependent manner. UPM-exposed fibroblasts caused the activation of ERK to increase HO-1 expression and decrease SOD2 expression. Treatment with curcumin reduced the UPM-mediated increase in ROS; this decrease in ROS occurred in a dose-dependent manner. The UPM-induced activation of ERK was inhibited by curcumin. Nrf2 production was also promoted to increase the expression of HO-1 and SOD2 by curcumin.

CONCLUSION

Curcumin reduced ROS production caused by UPM in human nasal fibroblasts in a dose-dependent manner, suggesting that curcumin has anti-oxidative effects and may be useful in the treatment of nasal diseases caused by UPM, such as allergic and chronic rhinitis.

α-Lipoic Acid Inhibits IL-8 Expression by Activating Nrf2 Signaling in Helicobacter pylori-infected Gastric Epithelial Cells

Helicobacter pylori (H. pylori) causes gastritis and gastric cancers. Oxidative stress is involved in the pathological mechanism of H. pylori-induced gastritis and gastric cancer induction. Therefore, reducing oxidative stress may be beneficial for preventing the development of H. pylori-associated gastric diseases. Nuclear factor erythroid-2-related factor 2 (Nrf2) is a crucial regulator for the expression of antioxidant enzyme heme oxygenase-1 (HO-1), which protects cells from oxidative injury. α-Lipoic acid (α-LA), a naturally occurring dithiol, shows antioxidant and anti-inflammatory effects in various cells. In the present study, we examined the mechanism by which α-LA activates the Nrf2/HO-1 pathway, suppresses the production of pro-inflammatory cytokine interleukine-8 (IL-8), and reduces reactive oxygen species (ROS) in H. pylori-infected AGS cells. α-LA increased the level of phosphorylated and nuclear-translocated Nrf2 by decreasing the amount of Nrf2 sequestered in the cytoplasm by complex formation with Kelch-like ECH1-associated protein 1 (KEAP 1). By using exogenous inhibitors targeting Nrf2 and HO-1, we showed that up-regulation of activated Nrf2 and of HO-1 results in the α-LA-induced suppression of interleukin 8 (IL-8) and ROS. Consumption of α-LA-rich foods may prevent the development of H. pylori-associated gastric diseases by decreasing ROS-mediated IL-8 expression in gastric epithelial cells.