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Updated: Sep 18, 2025
Microglia as a Surrogate Biosensor to Determine Nanoparticle Neurotoxicity
Published on: October 25, 2016
Microglial Dysfunction Mediated by Pb and Amyloid Beta Peptides as a Possible Mechanism of Neurotoxicity
Murumulla Lokesh1, Lakshmi Jaya Madhuri Bandaru1, Ajumeera Rajanna1
1Cell Biology Division, National Institute of Nutrition, Hyderabad, India.
Abstract:
This study delves into the inflammatory and degenerative impacts of lead (Pb) toxicity and amyloid beta peptides (Aβ-peptide 1-40 and Aβ-peptide 25-35) on brain cells, particularly by fostering M1 polarization in microglial cells and subsequent neuronal cell death, crucial in conditions like Alzheimer's disease. Microglia were exposed to IC50 concentrations of Pb, and Aβ-peptide 1-40 and Aβ-peptide 25-35 exhibited notable increases in intracellular ROS levels (32.95%) upon exposure to combinatorial treatments. Moreover, there was a significant decline in total antioxidant capacity to 69.57%, suggesting oxidative damage and compromised cellular defenses against stress, coupled with heightened glutamate levels (921.3 μM). Treatment with Pb alongside Aβ-peptide 1-40 and Aβ-peptide 25-35 also led to elevated intracellular calcium levels (33.83%) and increased production of pro-inflammatory cytokines IL-6 (5.54 pg/mL), TNF-α (5.8 pg/mL), and IFN-γ (13.52 pg/mL) and reduced levels of anti-inflammatory cytokines IL-10 (5.61 pg/mL) and IL-4 (14.46 pg/mL) in microglial cells compared with the control group. Furthermore, upregulation of NF-κB/p65 pathway-associated markers was observed, and when co-cultured with neuronal cells for 24 h, polarized microglia induced neuronal cell death (57.9%). These findings provide insights into the complex molecular mechanisms involved in lead-induced neurotoxicity and neurodegenerative disorders.
Insights
Lead toxicity and amyloid beta peptides promote M1 microglial polarization, increasing oxidative stress and neuronal death. This highlights mechanisms in neurodegenerative diseases like Alzheimer's.
Area of Science:
- Neuroscience
- Toxicology
- Cell Biology
Background:
- Lead (Pb) toxicity and amyloid beta (Aβ) peptides are implicated in neurodegenerative diseases.
- Microglial activation and polarization are key processes in neuroinflammation.
Purpose of the Study:
- To investigate the combined effects of lead and amyloid beta peptides on microglial cells.
- To elucidate the mechanisms of lead-induced neurotoxicity and its role in neurodegeneration.
Main Methods:
- Exposing microglial cells to lead (Pb) and amyloid beta peptides (Aβ-peptide 1-40, Aβ-peptide 25-35).
- Measuring intracellular reactive oxygen species (ROS), total antioxidant capacity, glutamate levels, intracellular calcium, and cytokine production (IL-6, TNF-α, IFN-γ, IL-10, IL-4).
- Analyzing NF-κB/p65 pathway activation and co-culturing with neuronal cells to assess neuronal cell death.
Main Results:
- Combined Pb and Aβ treatments significantly increased intracellular ROS and calcium levels.
- Total antioxidant capacity and anti-inflammatory cytokines (IL-10, IL-4) decreased, while glutamate and pro-inflammatory cytokines (IL-6, TNF-α, IFN-γ) increased.
- Upregulation of NF-κB/p65 pathway markers was observed, and polarized microglia induced significant neuronal cell death (57.9%).
Conclusions:
- Lead toxicity and amyloid beta peptides synergistically induce M1 microglial polarization and oxidative stress.
- These effects contribute to neuronal damage and cell death, relevant to Alzheimer's disease pathogenesis.
- The findings offer insights into the molecular mechanisms underlying lead-induced neurotoxicity.
