Journal: International Journal of Molecular Sciences
Article Title: Pseudomonas aeruginosa Triggered Exosomal Release of ADAM10 Mediates Proteolytic Cleavage in Trans
doi: 10.3390/ijms23031259
Figure Lengend Snippet: Functional implication of exosomal ADAM10 P. aeruginosa infection. ( A ) The 2 × 10 7 A549 cells were left unstimulated or infected with P. aeruginosa (MOI 5) in serum free medium for 2 h. Subsequently, the cell supernatant was subjected to differential centrifugation (300, 1000, 10,000, 100,000 g ). The pellets obtained in each sequential centrifugation step and the cells were lysed and subjected to Western blot analysis together with the unfractionated supernatants. Membranes were probed against ADAM10 (C-terminal antibody), Flotiline-1 and CD9 (positive markers for exosomes). ( B ) Extracellular vesicles from P. aeruginosa infected cells were collected as described in A and subjected to sucrose density gradient centrifugation after centrifugation at 100,000 g , Purity of fractions was controlled by optical density measurements, and fractions were subjected to Western blot analysis. Membranes were probed against ADAM10, Flotiline-1 and CD9. Notably, the ADAM10 positive fractions were identified as exosomes by the exosomal markers and the density. In ( A , B ), representative blots of at least three independent experiments are shown. ( C ) A549 cells were transfected with a plasmid encoding for AP-BTC and seeded at equal density. Cells were pre-incubated with ADAM10 inhibitor GI254023X (10 μM) or 0.1% DMSO (vehicle control) for 30 min. Subsequently, cells were left untreated (no exosomes) or co-incubated with exosomes derived from either non-infected or P. aeruginosa infected (MOI 5 for 2) cells. After 2 h, AP activity was determined in the cell lysate and supernatant to quantify the relative betacellulin cleavage and release. ( D ) A549 cells were transduced with lentivirus encoding shRNA against ADAM10 for knockdown (KD) (A10-KD1 or 10-KD2) or an unspecific shRNA (scramble, scr) as indicated in the graph legend. Cells for activity measurement were transfected with a plasmid encoding for AP-BTC prior to seeding. Cells for exosome preparation were not transfected. Cells were either left untreated or co-incubated with exosomes prepared from P. aeruginosa infected (MOI 5 for 2 h) scramble or A10 KD cells, respectively. After 2 h, AP activity was determined in the cell lysate and supernatant to quantify the relative betacellulin cleavage and release. Quantitative data are shown as means + SD of three independent experiments. Asterisks indicate significance among treated cells calculated using two-way ANOVA and Tukey post-test in ( C ) and one-way ANOVA and Tukey post-test in ( D ) (* p < 0.05, *** p < 0.001, **** p < 0.0001, n.s. not significant).
Article Snippet: Mouse monoclonal antibody against human CD9 (MM2/57); Rabbit polyclonal antibody against human ADAM10 C-terminus was obtained from Invitrogen (Frankfurt, Germany), rabbit polyclonal antibody against human GAPDH from Santa Cruz Biotech (Dallas, TX, USA).
Techniques: Functional Assay, Infection, Centrifugation, Western Blot, Gradient Centrifugation, Transfection, Plasmid Preparation, Incubation, Derivative Assay, Activity Assay, Transduction, shRNA