Fig. 4: Suppression of ABCG2 modulates PPIX distribution in EPP.

a Quantification of PPIX in the sera of Fech-mut mice treated orally with vehicle (control, n = 4 mice) or K31 (100 mg/kg, n = 4 mice). b PPIX levels in the sera of Fech-mut and Fech-mut/Abcg2-null mice (n = 3 mice for Fech-mut group, n = 4 mice for Fech-mut/Abcg2-null group). PPIX in serum was analyzed by UPLC-QTOFMS. Data are expressed as median with range. Two-tailed Mann–Whitney tests were used for statistical analysis, *P = 0.0286. c Expression of Abcg2 in the membrane of red blood cells (RBCs). Na⁺,K⁺-ATPase was used as a loading control for Western blotting. The effect of ABCG2 deficiency (d) or inhibition (e) on the percentage of PPIX efflux from RBCs. RBCs were collected from Fech-mut and Fech-mut/Abcg2-null mice and cultured with K31 (10 µM) or without K31 (Cont) for 1 or 3 h (n = 3 for each genotype, duplicate incubations for each sample). PPIX in the culture medium of RBCs was analyzed by fluorescence. Data are expressed as mean ± SEM. ***P = 0.0009, ****P < 0.0001, two-tailed t test. f A scheme showing that ABCG2 inhibitors prevent phototoxicity in EPP by modulating PPIX distribution. Source data are provided as a Source Data file.