Mechanistic insights into TDCPP-induced DNA damage in GT1-7 cells

Area of Science:

• Environmental toxicology
• Molecular biology
• Cellular toxicology

Background:

• Tris(1,3-dichloro-2-propyl) phosphate (TDCPP) is an organophosphate ester with known estrogenic activity and genotoxicity.
• The specific molecular mechanisms linking estrogen signaling pathways to TDCPP-induced genotoxicity are not fully understood.

Purpose of the Study:

• To investigate the role of estrogen receptors (ERα/β) and G protein-coupled estrogen membrane receptor 1 (GPER1) in TDCPP-induced DNA damage.
• To examine the involvement of downstream signaling pathways, specifically ERK1/2 and AKT, in mediating TDCPP's genotoxic effects.

Main Methods:

• Exposure of GT1-7 mouse hypothalamic cells to varying concentrations of TDCPP.
• Assessment of DNA damage markers (e.g., ATM, γ-H2AX), reactive oxygen species (ROS), malondialdehyde (MDA), mitochondrial damage, and micronucleus formation.
• Analysis of mRNA expression for DNA double-strand break (DSB) and single-strand break (SSB) repair genes.
• Inhibition studies using GPER1 antagonist (G15) and ERK1/2 inhibitor (U0126).

Main Results:

• TDCPP exposure increased ROS, MDA, DNA damage, G2/M cell cycle arrest, mitochondrial damage, and micronuclei formation.
• TDCPP upregulated key DNA double-strand break markers (ATM, γ-H2AX) and most DSB repair genes, while downregulating SSB repair genes.
• TDCPP enhanced GPER1 expression and ERK1/2 phosphorylation.
• Inhibiting GPER1 or ERK1/2 significantly reduced TDCPP-induced DNA damage and normalized repair gene expression.

Conclusions:

• TDCPP induces significant DNA damage and genotoxicity in mouse hypothalamic cells.
• The GPER1-ERK1/2 signaling pathway is critically involved in mediating TDCPP's genotoxic effects.
• Targeting the GPER1-ERK1/2 pathway may offer a strategy to mitigate TDCPP-induced cellular damage.