Fig 2: Urinary extracellular vesicles (EVs; microvesicles and exosomes) bearing six uric acid (UA)-transporters from UA stone formers (UASFs) and calcium stone formers (CSFs) and age-/sex-matched non-stone formers (NSFs). Urinary EVs were presented as the log10 of EVs/mg creatinine. * p < 0.05 UASFs or CSFs vs. NSFs; † p < 0.05 UASFs vs. CSFs (Wilcoxon rank sum test). The concentrations of SLC2A9, SLC17A3, and ZNF365-bearing EVs were greater than SLC22A12, SLC5A8, and ABCG2-expressing EVs in human urine.

Fig 3: Representative scatter plots and fluorescence dot plots from the FACSCanto™ flow cytometer. (A) Example scatter plot of buffer with fluorophore-conjugated antibodies and calibration beads (no samples). (B) Example scatter plot of diluted urine plus appropriate fluorophore-conjugated antibodies and calibration beads. (C–H) Fluorescent dot plot (quadrants derived from microvesicle gate (contain major portions of extracellular vesicles) of (B)) showing fluorophore spectra for Annexin-V and SLC2A9 antibodies (C), SLC17A3 antibodies (D), URAT1 antibodies (E), ZNF365 antibodies (F), ABCG2 antibodies (G), and SLC5A8 antibodies (H).

Fig 4: Expression and localization of ABCG2/Breast cancer resistance protein (BCRP) in human fetal membranes. (A) Real-time polymerase chain reaction (PCR) analysis of ABCG2 mRNA in the fetal membrane (FM) shows gene expression of ABCG2. The expression levels of ABCG2 are similar in both FM and placenta (PLA) tissues. (B) Representative immunohistochemistry images of FM and human stained for BCRP. BCRP was localized to both the amnion epithelial layer (1) and the chorion trophoblast layer (2) of the FM. The PLA staining serves as the positive control. (C) Western blots of BCRP in human FM compared to the PLA. Representative blots from n = 6 for each tissue type are shown. Data presented as mean ± SD.

Fig 5: Expression of BCRP transport protein in human fetal membrane cell lines. (A) Flow cytometer analysis for the surface expression levels of BCRP in FM cell lines are shown: Amnion epithelial cells (AEC); amnion mesenchymal cells (AMC); chorion trophoblast cells (CTC); and decidua cells (DEC). Placental BeWo trophoblast cells were used as a positive control throughout these experiments. Cells stained with PE-Isotype control are indicated with red color lines and cells stained with PE-BCRP1 are indicated with blue color lines and demonstrate a distinct peak. (B) Relative mean fluorescence intensity (MFI) from different FM cells were calculated by FlowJo and are represented as a bar graph. CTCs showed a significant increase in BCRP expression compared to other cell lines. (C) Western blots of human FM cell lines for expression of BCRP. Representative blots of BCRP expression from each cell type are shown (n = 6). Data presented as mean ± SEM. Statistical significance was determined by an unpaired student t-test considering BeWo as a control. * p < 0.05.