Fig. 3

Lipid droplets are transferred between astrocytes via TNTs and secretion. 3D z-stack image of a PLIN3 + LD and MHCII co-localizing within a TNT (a). Time-lapse microscopy follow transfer of LDs through TNTs over time (white arrow, b). Schematic illustration of the LD donor-acceptor experimental set-up (c). Cell-to-cell transfer of LDs occur both from Aβ-exposed astrocytes to control astrocytes (d) and from control astrocytes to Aβ-exposed astrocytes (e). Quantification of acceptor astrocytes with no detectable LDs (negative), low number of LDs (1–3 LDs/cell), or high number of LDs (> 3 LDs/cell) (f). For the statistical analysis of (f) N number is 3 and the data is presented in a bar graph with standard deviation. The level of significance for all the graphs is: * = P < 0.05, ** = P < 0.01, and *** = P < 0.001. Schematic illustration of the conditioned medium experiments (g). Lipid droplets were secreted and taken up by acceptor cells, both when Aβ exposed astrocytes (h) and control astrocytes (i) were donors. Scale bar (a, d,e, h,i): 20 μm; (zoomed in a): 5 μm