Endoplasmic reticulum stress associated with lead (Pb)-induced olfactory epithelium toxicity in an olfactory dark basal cell line

The effect of resveratrol on lead-induced oxidative damage and apoptosis in HT-22 cells

OBJECTIVE

The purpose of this work was to investigate whether resveratrol affects lead-induced oxidative damage in HT-22 cells, characterizing mechanisms and strategies for preventing and treating lead-induced neurotoxicity.

METHODS

Various lead and resveratrol concentrations were applied to HT-22 cells over different time periods. First, we established the lead treatment (12.5, 50 and 200 μmol/L) and resveratrol (40 μmol/L) intervention model for the study. MTT was used to analyze HT-22 cell survival rate. The rates of cell death, mitochondrial membrane potential, lipid peroxidation, and reactive oxygen species (ROS) generation were all measured by flow cytometry. Cellular oxidant (MDA) and antioxidant (SOD, GSH-Px) levels were measured with test kits. Western blotting was used to assess the expression of proteins related to autophagy and apoptosis.

RESULTS

Lead reduced HT-22 cell viability in a concentration/time-dependent manner. In addition, lead (200 μmol/L) decreased the protein expression of BCL2, while increasing PARP and BAX expression and apoptotic rate. Moreover, the lead-exposed group had significantly higher levels of ROS, lipid-ROS, and MDA than the control group. This was accompanied by increased MDA levels and decreased SOD, GSH-Px, and MMP levels in the lead-exposed cells. Furthermore, lead lowered SIRT1 protein expression, while increasing the levels of autophagy-related proteins, including P62, ATG5, Beclin-1 and LC3 Ⅱ/Ⅰ. Resveratrol (40 μmol/L), an agonist of SIRT1, restored the effects of lead (200 μmol/L) to levelsindistinguishable from controls.

CONCLUSION

Resveratrol inhibited mitochondrial damage and restored the lead-induced block of autophagic flux and oxidative stress by activating SIRT1, thereby alleviating lead-induced damage in HT-22 cells.

The Effects of Circadian Rhythm on Lead-Induced Toxicity in the DBC1.2 Olfactory Dark Basal Cell Line

BACKGROUND/OBJECTIVES

This study evaluated changes in circadian clock genes and mitochondrial function in a lead (Pb)-induced toxicity model of an olfactory epithelial cell line.

METHODS

The DBC1.2 olfactory dark basal cell line was used. Dexamethasone shock was used to reset the circadian clock 24 h (Group 1) and 36 h (Group 2) after seeding. Then, 60 h after seeding, the cells were treated with or without Pb (II) nitrate in HEPES buffer for 1 h. Mitochondrial function and cell viability were evaluated 84 h after seeding.

RESULTS

Mitochondrial function under Pb exposure was significantly impaired in Group 1 compared with Group 2. Cell numbers and viability did not significantly differ between groups. The mitochondrial membrane potential was significantly higher in Group 1 than Group 2, both without and with Pb exposure.

CONCLUSIONS

The circadian rhythm can alter the sensitivity to Pb-induced toxicity and mitochondrial damage in olfactory cells.

Heavy Metal Exposure: Molecular Pathways, Clinical Implications, and Protective Strategies

Heavy metals are often found in soil and can contaminate drinking water, posing a serious threat to human health. Molecular pathways and curation therapies for mitigating heavy metal toxicity have been studied for a long time. Recent studies on oxidative stress and aging have shown that the molecular foundation of cellular damage caused by heavy metals, namely, apoptosis, endoplasmic reticulum stress, and mitochondrial stress, share the same pathways as those involved in cellular senescence and aging. In recent aging studies, many types of heavy metal exposures have been used in both cellular and animal aging models. Chelation therapy is a traditional treatment for heavy metal toxicity. However, recently, various antioxidants have been found to be effective in treating heavy metal-induced damage, shifting the research focus to investigating the interplay between antioxidants and heavy metals. In this review, we introduce the molecular basis of heavy metal-induced cellular damage and its relationship with aging, summarize its clinical implications, and discuss antioxidants and other agents with protective effects against heavy metal damage.