LRRK2 deficient postmitotic DNs express proliferation marker. LRRK2 siRNA-treated (white bars) or control (black bars) hmNPC RNA displayed activation or reduction of important cell-cycle regulators in differentiated cells (A). LRRK2 siRNA-treated or control (scrambled siRNA) hmNPCs were co-stained for TH and Ki67 (B, C). Note a reduction in LRRK2 expression and disappearance of protrusions that normally characterize healthy dopaminergic cells (C). Terminally differentiated TH+ hmNPCs never exhibited Ki67 proliferation marker (B) which appeared in dopaminergic (TH+) siLRRK2 treated samples (arrows in C), particularly visible at higher magnification (insert corresponds to asterisk).