Fig. 1

Characterization of EV-OAT1 and uptake by tubuloids. a Scheme of the tubuloid differentiation protocols used. The days (D) between D-7 and D0 comprehend the expansion phase of tubuloids. D0–D7 regards the expansion phase. D0, D2 and D4 indicate the days where new stimulation was given (with differentiation medium, CM-OAT1 or EV-OAT1). The images in the right show light microscopy representative images of tubuloid cultures in the different conditions. b Nanoparticle Tracking Analysis representative graph of EV-OAT1. The graph shows the size distribution of EVs (abscissa) and their concentration in particles/ml (ordinate). c Representative Western blot showing the presence of OAT1 within EV-OAT1 cargo. d Representative Western blot showing the presence of CD63 as exosome marker in EV-OAT1. e Representative Western blot showing the presence of Na⁺/K⁺-ATPase within EV-OAT1 cargo. f Fluorescence image of fully differentiated ciPTEC-OAT1 culture stained with Vybrant DiI (in red) (scale bar = 500 µm). g Fluorescence image showing the uptake of stained EV-OTA1 (in red) by tubuloids after 24 h incubation (scale bar = 50 µm). h Representative confocal image of EV-OAT1 distribution into tubuloids after 24 h incubation. The nuclei of the cells were stained with DAPI (in blue) and the EVs were stained with Vybrant DiI (in red) (scale bar = 50 µm)