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David Poisson Pare Posted by David on Monday, October 25, 2010 (EST) Do metal nanoparticles have the ability to act as endocrine disrupting chemicals? Increasing numbers of in vivo and in vitro experiments report that exposure to engineered metal nanoparticles (EMNP) including nano¬ Ag, TiO2, ZnO and nano-Cu may result in DNA damages, inflammation, and cellular necrosis in different tissues, organs and organisms. However, no experiments with the precise objective to determine the capacity of nanoparticles to act as endocrine disrupting chemicals (EDC) exist, although EDC are known to be responsible for a large range of health problems in humans and wildlife. The rapid increase in the use of EMNP and consequently, the inevitable human and wildlife exposures to these particles logically lead to the following question: do EMNP have the potential to disrupt the hormonal signalling? Three hypotheses are advanced to the test this question: i) EMNPs do not directly activate estrogen receptors and trigger gene transcription; ii) EMNPs have the potential to disrupt the stimulating actions of estradiol on gene transcription; and, iii) EMNPs have the potential to modify the stimulating action of estradiol via non-genomic pathways. Practically, goldfish cells expressing nuclear and membrane-associated estrogen receptors will be exposed to metal nanoparticles (TiO2, ZnO, nano-Ag) alone or together with estradiol. Bulk counterparts or soluble counterparts of the metal constituting the nanoparticles will be used as control. The transciptomic response of these cells to these EMNPs will be monitored by microarray to identify endocrine-regulated genes. To observe the effect of EMNPs specifically on nuclear receptor signalling, the membrane receptor GPR30, will be knocked-out/down using small-interference-RNA (siRNA). Conversely, to observe the effect of EMNPs specifically on GPR30, the nuclear receptors will be knocked-out/down. This novel study should produce useful data on both the toxicity of EMNPs on fish cells and the specificity of the estrogenic signalling pathways in fish. Notify me when a new comment is posted Add Your Comment