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[Lead exposure aggravates Aβ1-42-induced microglial activation and copper ion accumulation in microglial cells]
1Department of Occupational Health and Occupational Medicine, School of Public Health, Southern Medical University, Guangzhou 510515, China.
Objective:
To investigate the effect of lead (Pb) exposure on Aβ1-42-induced microglial activation and copper ion accumulation in microglial cells and explore the regulatory mechanism of Pb-induced aggravation of Alzheimer's disease (AD)-like pathology.
Methods:
Cultured microglial BV2 cells were treated with different concentrations of Aβ1-42, lead acetate or their combination for 12 h, and the changes in cell viability and morphology were evaluated. Immunofluorescence assay was performed to detect iNOS and oxidative stress level in the treated cells, and the release of inflammatory factors was detected using ELISA. Western blotting and inductively coupled plasma-mass spectrometry (ICP-MS) were used to detect the expressions of CTR1 and ATP7A proteins and copper content in the cells.
Results:
Treatment with 15 and 20 μmol/L Aβ1-42 for 12 h significantly lowered the viability of BV2 cells. Treatment with Aβ1-42 at 10 μmol/L for 12 h obviously increased the release of iNOS, TNF-α and IL-6 in the cells (P<0.05), and its combination with 15 or 20 μmol/L lead acetate more strongly lowered BV2 cell viability (P<0.05). Compared with 10 μmol/L Aβ1-42 treatment alone, 10 μmol/L Aβ1-42 combined with 10 μmol/L lead acetate for 12 h caused more obvious microglial activation, as manifested by enlarged cell bodies, increased cell protrusions and elongation, enhanced release of iNOS, TNF-α, IL-6, IL-1β and ROS, and increased intracellular copper ion accumulation and expression of copper transporter CTR1 (P<0.05). Compared with the conditioned medium from activated BV2 cells, which caused obvious injuries in hippocampal neuron HT22 cells (P<0.001), the medium from BV2 cells treated with NAC and the copper ion chelating agent TM caused milder injuries in HT22 cells (P<0.05).
Conclusion:
Lead exposure aggravates neuronal damage caused by Aβ1-42-treated microglial cells by increasing copper ion accumulation, oxidative stress, and inflammatory factor release to trigger microglial activation.
Insights
Lead exposure worsens Alzheimer's disease (AD) pathology by increasing microglial activation and copper accumulation. This study reveals how lead (Pb) exposure exacerbates amyloid-beta (Aβ1-42)-induced neuroinflammation and neuronal damage.
Area of Science:
- Neuroscience
- Toxicology
- Cell Biology
Context:
- Alzheimer's disease (AD) is characterized by amyloid-beta (Aβ) plaques and neuroinflammation.
- Microglial cells are key players in the brain's immune response and can be activated by Aβ.
- Environmental toxins, such as lead (Pb), may influence AD pathogenesis.
Purpose:
- To investigate the impact of lead (Pb) exposure on Aβ1-42-induced microglial activation.
- To examine Pb-induced alterations in copper ion accumulation within microglial cells.
- To elucidate the mechanism by which Pb exacerbates AD-like pathology.
Summary:
- Exposure to lead (Pb) significantly enhances Aβ1-42-induced microglial activation, characterized by increased inflammatory mediator release (iNOS, TNF-α, IL-6, IL-1β) and oxidative stress (ROS).
- Pb exposure leads to elevated intracellular copper ion accumulation and increased expression of the copper transporter CTR1 in microglial cells.
- Conditioned medium from Pb-exposed, Aβ1-42-activated microglia causes significant neuronal damage, which is partially mitigated by antioxidants and copper chelators.
Impact:
- Demonstrates that lead exposure acts as a critical factor in aggravating Aβ1-42-induced neuroinflammation and neuronal injury.
- Highlights the role of copper ion dysregulation and oxidative stress in Pb-mediated exacerbation of AD-like pathology.
- Provides insights into potential therapeutic targets for mitigating environmental toxin-induced neurodegeneration.
