Perinatal exposure to glyphosate or a glyphosate-based formulation causes longterm epigenetic alteration associated with implantation failures

ALMIRÓN, AILÍN; CADAVIZ, DALMA B.; LORENZ, VIRGINIA; DONÁ, FLORENCIA; VARAYOUD, JORGELINA; MILESI, MARÍA M.

Mar del Plata

Congreso; Reunión de Sociedades de Biociencias - LXVII Reunión Anual de la Sociedad Argentina de Investigación en Clínica (SAIC); 2022

Sociedades SAIC, SAI, FAIC & SAFIS

Glyphosate (Gly) is the active ingredient of glyphosate-based herbicides(GBH); the most globally used pesticide. We have shownthat perinatal exposure to either Gly or GBH induces implantationfailure in rats. Here, we investigate whether this alteration is associatedwith aberrant uterine expression of leukemia inhibitory factor(Lif) gene, a key marker of endometrial receptivity, and we exploredepigenetic mechanisms of transcriptional regulation. Pregnant rats(F0) were exposed to Gly or GBH through food, in a dose of 2 mgof glyphosate/kg/day, from gestational day (GD) 9 until weaning.Sexually mature F1 females became pregnant and uterine sampleswere collected on GD5 (preimplantation period). The mRNAexpression of Lif was evaluated by RT-qPCR. To analyze the methylationstatus of Lif, enzyme-specific restriction sites were searchedin silico in the regulatory regions of the gene and assessed usingthe methylation-sensitive restriction enzymes-PCR technique. Todetermine changes in histone post-translational modifications, histoneacetylation (H3Ac and H4Ac) and methylation at lysine residues(H3K27me3) along the different regulatory regions of Lif wereassessed by chromatin immunoprecipitation (ChIP) assays. Gly andGBH exposure decreased the mRNA expression of Lif. Moreover,an increase in DNA methylation was detected in Gly- and GBH-exposedrats, compared with the control. In most of the regions analyzed,ChIP data showed increased levels of H3Ac in GBH group,but decreased acetylation levels in Gly group vs control. RegardingH4Ac, no significant changes were detected. In addition, Gly andGBH groups showed higher level of H3K27me3 in one of the regionsanalyzed, compared to the control. In conclusion, perinatal exposureto Gly or GBH downregulates the expression of Lif at the receptivestage, associated with epigenetic disruption of the regulatoryregions of the gene. These alterations could account for the Gly- andGBH-induced implantation failures.