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. 2024 Jun 18;15:5199. doi: 10.1038/s41467-024-49597-z

Fig. 5. P2X7 Receptors mediate CSDS-induced alterations in MAMs within hippocampal microglia.

Fig. 5

a Representative confocal images of primary microglia untreated (Control) or treated with ATP (1 mM) from P2X7R−/− mice stained for nuclei (Hoechst 33342, blue), endoplasmic reticulum (ER-Tracker, green), and mitochondria (Mito-Tracker, red, left panel) and quantification of the colocalization between ER and mitochondria (right panel). Scale bar: 20 μm; Student’s t test (P = 0.3313). Data are expressed as mean ± SEM (n = 4 batches of mouse extracted cell samples). ns, p > 0.05. b Representative images of PLA targeting IP3R3-GRP75 or GRP75-VDAC1 interactions in the hippocampal DG (left panel) and Quantification of the PLA red fluorescent dots (Top line, Interaction, F (1, 8) = 0.000, P > 0.9999) and the percentage of PLA dots in microglia (Bottom line, Interaction, F (1, 8) = 0.001815, P = 0.9671) were performed using Image J (right panel). Scale bar: 20 μm; Microglia (Iba-1, green), Nuclei (DAPI, blue). Two-way ANOVA with Sidak’s multiple comparisons test. Data are expressed as mean ± SEM (n = 3 mouse brain slices). *p < 0.05. c Immunoelectron microscope images with higher magnification of the inset showing the intimate proximity between mitochondria (M) and ER in a gold labeled microglia (Mi) (Red arrow: dense black dots) located in the hippocampal DG from CSDS and P2X7R−/− mice with CSDS. Source data are provided as a Source Data file. d Schematic diagram of the involvement of mitochondria-associated membranes (MAMs) in mediating extracellular ATP (eATP)/P2X7R-induced microglial responses and chronic social defeat stress (CSDS)-induced depression-like behaviors. CSDS induces ER stress, structural and functional alterations in MAMs, and mitochondrial impairment in hippocampal microglia. Reduced GRP75 expression in microglia of Cx3cr1CreER/+Hspa9f/+ mice or knockout P2X7 in P2X7R-/- mice results in decreased depressive behaviors, reduced NLRP3 inflammasome aggregation, and fewer ER-mitochondria contacts in hippocampal microglia during CSDS. Figure 5d was created with BioRender.com released under a Creative Commons Attribution-Non-Commercial-No Derivs 4.0 International license.