Figure 2. Placental 5-HT is dependent on SERT-mediated uptake.
(A) Schematic depicting potential modes of placental 5-HT acquisition examined in this study. (B, C) Normalized counts indicating Sert (Slc6a4) and Oct3 (Slc22a3) are expressed in both male and female placental tissues at E12.5, with no differences by sex (unpaired Student’s t-test; Slc6a4: p = 0.3677; Slc22a3: p = 0.5973). (D) The Tph1 gene is not expressed in E12.5 placental tissues. N=4 samples/sex. Data are median ± interquartile range. (E) Assessment of 5-HT levels in E12.5 placental tissues shows significant reductions (one-way ANOVA, F(3,8) = 4.001, p = 0.0004) in Sert KO (Dunnett’s multiple comparisons test; ***adjusted p = 0.0003), Tph1 KO (**adjusted p = 0.0015), and Oct3 KO (*adjusted p = 0.04) tissues. N=3–5/group. (F) Western blot analysis of placental tissues at E12.5, showing reduced H3K4me3Q5ser in Sert KO, Tph1 KO and Oct3 KO tissues (one-way ANOVA, F(3,10) = 15.37, *p = 0.05). Peptide competition assays using H31–10 peptides show selective signal of the serotonyl-PTM epitope is predominantly observed in WT placenta. N = 3/group. Data are mean ± SEM.