In-depth comparative toxicogenomics of glyphosate and Roundup herbicides: Histopathology, transcriptome and epigenome signatures, and DNA damage
Mesnage, Robin et al. (2021), In-depth comparative toxicogenomics of glyphosate and Roundup herbicides: Histopathology, transcriptome and epigenome signatures, and DNA damage, Dryad, Dataset, https://doi.org/10.5061/dryad.1g1jwstxk
Whether or not glyphosate activates cellular mechanisms involved in carcinogenesis remains controversial. We tested whether glyphosate and three glyphosate-based commercial herbicide formulations activate mechanisms known to be key characteristics of carcinogens. The mammalian stem cell-based genotoxicity ToxTracker assay showed that the representative EU formulation Roundup MON 52276 and the UK formulation Roundup MON 76473, but not glyphosate and the US Roundup formulation MON 76207, activated oxidative stress and unfolded protein responses. High-throughput molecular profiling of liver function was performed in female Sprague-Dawley rats exposed to glyphosate or MON 52276 (both at 0.5, 50, 175 mg/kg bw/day glyphosate equivalent concentration) for 90 days. Histopathology and serum biochemistry analysis showed that MON 52276 but not glyphosate treatment increased hepatic steatosis and necrosis. MON 52276 and glyphosate altered the expression of genes in liver reflecting TP53 activation by DNA damage and the regulation of circadian rhythms. The most affected genes in liver also had their expression similarly altered in kidneys. Small RNA profiling in liver showed miR-22 and miR-17 had their levels decreased by MON 52276, while mir-30 levels were decreased, whilst miR-10 levels were increased by glyphosate. DNA methylation profiling of liver revealed 5,727 and 4,496 differentially methylated CpG sites between the control and glyphosate and MON 52276 exposed groups of animals respectively. Direct DNA damage measurement by apurinic/apyrimidinic lesion formation in liver was increased with glyphosate exposure. Altogether, our results show that Roundup herbicide formulations are causing more biological changes than glyphosate alone, activating mechanisms involved in cellular carcinogenesis.