Extended Data Figure 5. Role of astrocytic CD38 in mitochondria transfer during starvation in vitro.

a, Immunocytochemistry in neuron-astrocyte co-cultures demonstrated that CD38 was primarily expressed within astrocytes. b, Extracellular ATP levels were higher in media collected from neurons co-cultured with astrocytes compared to neuron-alone cultures alone (n=9 or 11). c, After serum/glucose starvation, neurons were significantly damaged, as expected. But neurons co-cultured with astrocytes were protected (n=6 or 4). d, CD38 suppression with siRNA significantly decreased extracellular ATP levels in neuron-astrocyte co-culture, but CD38 suppression did not affect extracellular ATP level in neuron-alone cultures (n=9 or 6). e, Blockade of astrocytic CD38 with siRNA significantly increased LDH release (indicative of cell damage) in the co-culture, suggesting that CD38 may be important to maintain neuroglial homeostasis (n=6). f, Rat primary neurons were co-cultured with rat astrocytes. Immunocytochemistry showed that CD38 suppression with siRNA reduced astrocytic mitochondria (red) transfer into neurons compared to control. g, h, Western blot analysis indicated that CD38 suppression with siRNA can be successfully performed in astrocyte culture without affecting cell viability (n=4 or 3). All values are mean +/− SEM.