Fig 2: Schematic representation and proposed working model summarizing the results in EMC patients. Our findings suggest that a decreased autophagy status triggers Bcl-2-dependent oxidative stress in EMC patients. The decreased expression of ABCG1 is associated with dysregulated autophagy processes. The elevated ABCG2 expression represents a protective feedback mechanism under inhibited autophagic conditions. The aberrant gene expression of placental ABC transporters affects materno-fetal cholesterol transport in EMC. Impaired total antioxidant capacity and increased oxidative stress may further contribute to EMC (created with BioRender).

Fig 3: Protein expression changes in ABC transporters in placental tissues. (A) ABCG1 and (B) ABCG2 expression visualized by immunoblotting in placentae from (a) first trimester and term controls (n = 6 and n = 5, respectively, Swiss cohort) and (b) EMC patients and term controls (n = 20 and n = 19, respectively) was quantified by fluorescence detection analysis and normalized to ß-actin as loading control. Results of representative immunoblots for ABCG1 and ABCG2 are shown. Reduced ABCG1 and increased ABCG2 protein levels were observed in EMC patients. Statistical analysis was performed by using two-tailed Mann–Whitney test for comparing first trimester vs. term controls (a) and EMC vs. term controls (b); ‡: p = 0.001, †: p = 0.01).

Fig 4: qRT-PCR analysis of ABC transporters. mRNA expression of selected ABC transporters was measured in placentae from (A) first trimester and term controls (n = 6 and n = 5, respectively; Swiss cohort) and (B) EMC patients and term controls (n = 20 and n = 19, respectively). mRNA abundances of (a) ABCA1, (b) ABCG1, and (c) ABCG2 are presented as 2-?CT (?CT= CT value of target gene—CT value of the mean of reference genes ß-actin, GAPDH, YWHAZ, B2MG, L19, hTBP, and hsUBQ). Data are presented as mean (x), median (-), and Tukey box and whiskers (1.5 times interquartile range). ABCG1 was significantly lower, whereas ABCG2 mRNA expression increased in ECM. Statistical significance was evaluated by using two-tailed Mann–Whitney test for comparing first trimester vs. term controls (Swiss cohort) (A) and EMC vs. term controls (B); † (p = 0.01), * (p = 0.05). Abbreviations: ß-actin, beta-actin; GAPDH, Glyceraldehyde-3-phosphate dehydrogenase; YWHAZ, 14-3-3 protein zeta/delta; B2MG, beta-2 microglobulin; L19 (RPL19), ribosomal protein L19; TBP, TATA-box-binding protein; UBC, ubiquitin.

Fig 5: Effect of OCLN overexpression on cytotoxicity of anticancer drugs. (A) Mock and OCLN-expressing cells were treated with CDDP or DXR for 48 h. Cell viability was measured by WST-1 assays. (B) The expression of ABCB1, ABCC1, ABCC2, ABCG2, and ß-actin in cell lysates was examined by western blotting. The protein levels of ABC transporters are shown as a percentage of the values in mock cells. The full-length blot images are shown in Supplementary Fig. S4. (C) The mRNA levels of ABCB1, ABCC1, ABCC2, ABCG2 are shown as a percentage of the values in mock cells. n = 3–6. NS, P > 0.05 compared with mock cells.