Persistent neurobehavioral and neurochemical anomalies in middle-aged rats after maternal diazinon exposure

Exploring molecular mechanisms of diazinon toxicity in HT22 hippocampal neurons through integrated miRNA and mRNA profiling

Diazinon (DZN), a persistent organophosphate insecticide, has been associated with neurotoxic effects, particularly in the hippocampus. However, the specific molecular mechanisms of DZN-induced hippocampal toxicity remain unknown. In this study, we analyzed the mRNA and miRNA expression patterns of HT22 cells following exposure to DZN (125 μM), and the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted subsequently. The integration of miRNA sequencing (miRNA-seq) and mRNA sequencing (mRNA-seq) data identified 33 differentially expressed miRNAs (DEMIs, 15 up-regulated and 18 down-regulated) and 271 differentially expressed mRNAs (DEMs, 69 up-regulated and 202 down-regulated) targeted by the DEMIs. Moreover, the 3 most central mRNAs (ITGAV, FN1, and EGFR) and 7 associated miRNAs (mmu-miR-700-5p, mmu-miR-26a-2-3p, mmu-miR-452-3p, mmu-miR-25-3p, mmu-miR-582-5p, mmu-miR-467a-5p, and mmu-miR-467b-5p) were screened and validated using quantitative real-time PCR. Furthermore, the GO analysis revealed that the identified DEMs were enriched in biological adhesion extracellular matrix, and growth factor binding, while the KEGG analysis suggested that the enriched DEMs were involved in ECM-receptor interaction, mTOR signaling pathway, MAPK signaling pathway, and AMPK signaling pathway. Our results may aid in elucidating the underlying mechanisms associated with DZN-induced hippocampal toxicity and provide valuable insights into the pathogenesis of neurotoxicity triggered by other organophosphorus pesticides.

Developmental exposure to the flame retardant, triphenyl phosphate, causes long-lasting neurobehavioral and neurochemical dysfunction

BACKGROUND

Human exposures to organophosphate flame retardants result from their use as additives in numerous consumer products. These agents are replacements for brominated flame retardants but have not yet faced similar scrutiny for developmental neurotoxicity. We examined a representative organophosphate flame retardant, triphenyl phosphate (TPP) and its potential effects on behavioral development and dopaminergic function.

METHODS

Female Sprague-Dawley rats were given low doses of TPP (16 or 32 mg kg^-1  day^-1 ) via subcutaneous osmotic minipumps, begun preconception and continued into the early postnatal period. Offspring were administered a battery of behavioral tests from adolescence into adulthood, and littermates were used to evaluate dopaminergic synaptic function.

RESULTS

Offspring with TPP exposures showed increased latency to begin eating in the novelty-suppressed feeding test, impaired object recognition memory, impaired choice accuracy in the visual signal detection test, and sex-selective effects on locomotor activity in adolescence (males) but not adulthood. Male, but not female, offspring showed marked increases in dopamine utilization in the striatum, evidenced by an increase in the ratio of the primary dopamine metabolite (3,4-dihydroxyphenylacetic acid) relative to dopamine levels.

CONCLUSIONS

These results indicate that TPP has adverse effects that are similar in some respects to those of organophosphate pesticides, which were restricted because of their developmental neurotoxicity.