3.8 Differentially Methylated Genes and Targeted Genic Regions for Dysregulation
To evaluate the potential molecular consequences of iAs exposure, we identified genes containing DMCs and DMRs (Supplemental Table 1 ). Identified genes were catalogued based on DMC content. Several top DMC and DMR contain genes were associated with neurological function, retina or cornea function and anatomy, along with cell junction and membrane integrity. In relation to the specific diseases connected to iAs exposure, we identified genes essential to liver function and associated diseases. For example, our data included genes associated with T2D and insulin resistance(Ali 2013) such as Pik3c2g (Saeed 2018) (F2 female 245 ppb), Ptprn2 (Ouni et al. 2020) (F2 male 245 ppb), Adcy5 (Sommese et al. 2018) (F1 male 10 ppb and F2 female 10 ppb), and Slc27a4 (Rowlands et al. 2014) ( F1 male 10 ppb). We also found dysregulated methylation within Slc43a2 (Owaydhah et al. 2021) (F2 female 245 ppb) and Bicc1 (Park et al. 2016) (F1 male 245 ppb), genes that are associated with placental development and embryogenesis. Within the generational overlap, we found several genes associated with T2D such as Irs2 (10 ppb females), Tcf12(245 ppb males), Jazf1 (10 ppb females), Adcy5 (10 ppb males), and Slc27a (245 ppb females)(Ali 2013). We also identified genes associated with obesity, such as Adipor1 (F1 female 10 ppb), Fto (F1 male 10 ppb), Pparg (F2 male 245 ppb), and Adcy3 (F1 male 245 ppb) within our DMC list(Loos and Yeo 2021).
Using AnnotatR, we determined introns, 1 to 5 kb regions were the most sensitive while intergenic regions were most protected from iAs exposure by using the randomize regions function (Supplemental Figure 5-16). This function determines if differential methylation happens by chance or if specific regions are more responsive to exposure compared to others. Across sex, dose, and generation, we found introns and 1 to 5 kb regions contained more DMCs compared to other genic regions. In addition, intergenic regions were less sensitive to iAs exposure, indicating intergenic regions may be protected from dysregulation caused by iAs exposure.