Fig 1: Neurodegeneration phenotypes of trimethylamine N-oxide (TMAO)-treated midbrain organoids. (A,B) Representative IF images showing the ERK phosphorylation (A) and CaMKII/BDNF (B) in the indicated organoid group. Hoechst was used for counter nuclei staining. (C) Quantifications of the ERK phosphorylation (left), CaMKII (middle), and BDNF (right) in the indicated organoid group. (D,E) Representative IF images showing the TH- and TUJ-1 positive neurons (D) and synaptic marker expression (PSD-95 and Synaptophysin) (E) in the indicated organoid group. Hoechst was used for counter nuclei staining. (F) Quantifications of the TH, TUJ-1 (left), PSD-95, and Synaptophysin (right) in the indicated organoid group. (G) Quantification of dopamine secretion to conditioned media from indicated organoids. (H) Representative Fontana-Masson staining images for neuromelanin at 8 weeks of maturation in midbrain organoids. (I) Quantifications of Fontana-Masson staining. Data are AVE ± SD [P < 0.05(*), P < 0.01(**), P < 0.001(***)]. (Scale bar = 20 µm).