Toxic metals and autophagy

Area of Science:

• Environmental Toxicology
• Cellular Biology
• Molecular Mechanisms of Disease

Background:

• Finite Earth resources are overexploited, leading to industrialization and toxic metal contamination.
• Toxic metals cause bioaccumulation and cellular damage, with cytopathological features linked to diseases.
• Autophagy (programmed cell death type II) is a cellular process for homeostasis and stress response.

Purpose of the Study:

• To review the comparative cytotoxicity of metals/metalloids and nanoparticles (As, Cd, Cr, Hg, Fe, metal-NP) in cells undergoing autophagy.
• To analyze the role of autophagy as a cellular response to metal-induced toxicity.
• To identify key signaling pathways involved in autophagy induction or inhibition by metals/metalloids and nanoparticles.

Main Methods:

• Literature review analyzing studies on metal/metalloid and nanoparticle cytotoxicity.
• Focus on cellular responses involving autophagy, apoptosis, and necrosis.
• Identification of signaling pathways (MAP kinases, PI3K, AKT, mTOR, AMP kinase) and proteins (ATG8/LC3) implicated in metal-induced autophagy.

Main Results:

• Autophagy is an initial cellular response to toxic metals, occurring in a concentration- and time-dependent manner.
• Metals/metalloids and nanoparticles preferentially induce autophagy via ATG8/LC3 in various cell lines and animal models.
• Specific signaling pathways significantly regulate autophagy induction or inhibition in response to metal/metalloid and nanoparticle exposure.

Conclusions:

• Autophagy plays a critical role in cellular defense against metal-induced toxicity, although its precise role in tumorigenesis requires further study.
• Understanding autophagy's response to environmental stressors like toxic metals is crucial for developing biomarkers for toxicology.
• Key signaling pathways and proteins are involved in modulating autophagy, offering potential targets for therapeutic interventions against metal toxicity.