Fig. 2: Gonococcal OMVs target mitochondria and induce mitophagy.
From: Gonococcal OMV-delivered PorB induces epithelial cell mitophagy
a Western blots of OMV-stimulated HeLa cells show specific autophagosome/lysosome-dependent degradation of mitochondrial marker proteins (TOM20 and TIM23), but not of Golgi (GM130) or endoplasmic reticulum (PDI). Western blots are representative of 3 independent experiments. b DiO-labeled gonococcal OMVs from strain ATCC 49226 colocalize with MitoBright-labeled mitochondria in HeLa cells. Scale bar, 5 μm. c Live HeLa cell microscopy and 3D image reconstruction shows OMVs remain associated with Cascade Blue-labeled endosomes when delivered to MitoBright-labeled mitochondria. Scale bar, 5 μm. The fluorescence colocalization profile of the line is shown. d Gonococcal OMVs from strain ATCC 49226 dissipate the mitochondrial membrane potential (MMP) in HeLa cells. Scale bar, 5 μm. Data are mean ± s.d.; n = 50 cells, unpaired two-tailed t-test, P < 10−15. e TEM of HeLa cells stimulated with gonococcal OMVs from strains ATCC 49226 and ZJXSH86 show mitochondrial disruption and capture in mitophagy-like structures. Data are mean ± s.d.; n = 21 cells, one-way ANOVA with post-hoc Tukey test for mitochondrial disruption (Mock-ATCC 49226 OMVs: P = 2 × 10−11; Mock-ZJXSH86 OMVs: P = 2 × 10−11), Kruskal–Wallis with posthoc Dunn test for mitochondria in mitophagy-like structures (Mock-ATCC 49226 OMVs: P = 1 × 10−6; Mock-ZJXSH86 OMVs: P = 7 × 10−6). f Quantitative real-time PCR showing a reduced mitochondrial to genomic DNA ratio in ATCC 49226 OMV-stimulated HeLa cells. Data are mean ± s.d.; n = 3 independent biological replicates, one-way ANOVA with post-hoc Tukey test. g Increased HSP60 and LAMP1 colocalization in ATCC 49226 OMV-stimulated HeLa cells. Scale bar, 5 μm. Data are mean ± s.d.; n = 50 cells, unpaired two-tailed t-test, P = 6 × 10−9. h Increased HSP60 and LC3 colocalization in ATCC 49226 OMV-stimulated HeLa cells. Scale bar, 5 μm. Data are mean ± s.d.; n = 50 cells, two-tailed Mann–Whitney test (LC3 puncta Mock-OMVs: P = 7 × 10−12; LC3 colocalized HSP60 Mock-ZJXSH86 OMVs: P = 4 × 10−15). Cells in d, e, g, h are from 3 independent experiments. Images in b, c are representative of 3 independent experiments. Source data are provided as a Source Data file.
