Reduced expression of cholesterol metabolism in the glia from FTD-TDP patients. (A) Schematic illustration of spinal organoids differentiation from iPSC. (B) Confocal images of TDP-43 (left), HMGCS1 (middle), and HMGCR (right) with mature oligodendrocyte marker (CC1). DAPI nuclear stain in blue. Enlarged images show TDP-43, HMGCS1, and LDLR1 with oligodendrocytes. Scale bar = 50 µm. For magnified images, scale bar = 10 µm. (C) Schematic of post-mortem human FTLD-TDP tissues used for this study. (D) Double IF shows cytoplasmic TDP-43 inclusions (green) associated with white matter oligodendrocytes. Oligodendrocytes with TDP-43 inclusions appear to show a decrease in HMGCR (top, red, arrowheads) and HMGCS1 (middle, red, arrowheads) staining compared with other glial cells (arrows). LDLR colocalizes with TDP-43 inclusions (bottom, red). DAPI nuclear counterstain is blue. White image was taken using 561-nm excitation and corresponds to autofluorescence (autofluo.). Scale bar = 5 µm. DIV, days in vitro; SHH, Sonic Hedgehog; AA, ascorbic acid; WM, white matter.