Early epigenetic alterations in cardiac tissue following perinatal sertraline exposure in mice

Introduction Maternal use of selective serotonin reuptake inhibitors (SSRIs), including sertraline, has been associated with an increased risk of congenital heart defects, but the underlying mechanisms remain unclear. SSRIs cross the placenta and may influence cardiac development during sensitive periods. Previous work showed that perinatal sertraline exposure impairs postnatal growth, alters cardiomyocyte calcium handling, dysregulates serotonin signaling genes ( Htr2a , Htr2b , and Slc6a4 ), and chronically reduces left ventricular size. We hypothesized that these effects may involve early epigenetic alterations in cardiac DNA methylation. Materials & methods Adult female C57BL/6J mice received daily intraperitoneal injections of sertraline (5 mg/kg) or saline for five days before mating and throughout gestation. Offspring continued to receive 1.5 mg/kg of sertraline until postnatal day 14 (PN14), when hearts were collected. Global DNA methylation (5-methylcytosine, 5-mC) was quantified using a colorimetric ELISA assay. Targeted bisulfite sequencing (TBS-seq) profiled CpG methylation across predefined promoter and regulatory regions of 10 genes involved in serotonin signaling and cardiac function. Regional differential methylation was analyzed across 23 regions using overdispersion-corrected logistic regression with Benjamini–Hochberg (BH) adjustment. Results Global 5-mC levels did not differ significantly between sertraline-exposed and control groups. TBS-seq identified 1,941 CpG sites across 25 targeted regions. After coverage and regional quality filtering, 1,411 CpG sites across 23 regions were retained. Regional analysis identified two regions with significant differential methylation after FDR correction: the Htr2a enhancer showed an 8.19% increase in methylation ( p < 4.1 × 10 −15 , q < 9.4 × 10 −14 ), whereas the Tph2- associated region showed a 3.00% decrease in sertraline-exposed animals ( p < 0.0020, q < 0.0229). Secondary site-level analyses identified no individual CpG sites that remained significant after multiple-testing correction. Overall methylation profiles were highly correlated across samples, with no significant global difference between treatment groups. Discussion Perinatal sertraline exposure was associated with localized regional DNA methylation changes in neonatal cardiac tissue without a global change in 5-mC. The Htr2a enhancer and Tph2- associated region represent candidate regulatory loci linking early-life SSRI exposure with cardiac serotonergic pathways. These findings support further investigation of regional epigenetic alterations using integrated methylation, transcriptomic, and cell-type-resolved approaches to determine their functional significance and potential contribution to later-life cardiovascular outcomes.