CLN5-deficient human neurons exhibit reduced acidic organelles. (A,B) Microscopic analysis of acidic organelles in the iPSC-derived human neurons revealed reduced acidic organelles (measured by LysoTracker—compare pseudo-colour green) in CLN5i neurons (#2 and #3) compared to control neurons. (C,D) The microscopic analysis of acidic organelles was validated by flow cytometric analysis. (E) The CLN5i human neurons did not show any difference in lysosome mass, measured by quantification of LAMP1-neuonGreen-positive organelles using flow cytometry. n ≥ 3, * p < 0.05, ** p < 0.01, *** p < 0.001. Scale bar = 20 µm.