Figure 2.

Mitochondrial heterogeneity in co-cultures of U87-GBM cells and human primary astrocytes. (A–D) Transmission electron microscopy (TEM) of co-cultures of GBM cells, U87-GBM, and human primary astrocytes indicates that tumor cells have a heterogeneous intracellular distribution of key organelles essential for TNT formation and transport. (A, B) Correspond to TEM from the same cells at the bottom and top optical sections of the cells, respectively. Arrows indicate the interactions between enlarged mitochondria and lipid bodies as well as the endoplasmic reticulum. Overall, top optical sections, where TNT are formed, present a bigger structure with more interactions with other organelles suggesting different metabolism. Arrows indicate these interactions. Bar: 0.5 µm. (C, D) Also, denote the same points of pictures (A) and (B), but at different magnification. Bar: 1 µm. (E) Quantification of the mitochondrial area at the top and bottom of cells in the co-culture system. GBM, top, has a higher mitochondrial area. (F) Quantification of mitochondrial length (µm) at the top and bottom sections. (G) Quantification of mitochondrial-lipid body interactions indicating the cells have intracellular heterogeneity and specific location associated with TNT formation (cells analyzed per experiment was 50 per condition, n = 5 independent experiment).