Inhibition of mitophagy drives macrophage activation and antibacterial defense during sepsis
Danish Patoli, … , Laurent Lagrost, Charles Thomas
Danish Patoli, … , Laurent Lagrost, Charles Thomas
Published August 6, 2020
Citation Information: J Clin Invest. 2020;130(11):5858-5874. https://doi.org/10.1172/JCI130996.
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Research Article Inflammation Metabolism

Inhibition of mitophagy drives macrophage activation and antibacterial defense during sepsis

Abstract

Mitochondria have emerged as key actors of innate and adaptive immunity. Mitophagy has a pivotal role in cell homeostasis, but its contribution to macrophage functions and host defense remains to be delineated. Here, we showed that lipopolysaccharide (LPS) in combination with IFN-γ inhibited PINK1-dependent mitophagy in macrophages through a STAT1-dependent activation of the inflammatory caspases 1 and 11. In addition, we demonstrated that the inhibition of mitophagy triggered classical macrophage activation in a mitochondrial ROS–dependent manner. In a murine model of polymicrobial infection (cecal ligature and puncture), adoptive transfer of Pink1-deficient bone marrow or pharmacological inhibition of mitophagy promoted macrophage activation, which favored bactericidal clearance and led to a better survival rate. Reciprocally, mitochondrial uncouplers that promote mitophagy reversed LPS/IFN-γ–mediated activation of macrophages and led to immunoparalysis with impaired bacterial clearance and lowered survival. In critically ill patients, we showed that mitophagy was inhibited in blood monocytes of patients with sepsis as compared with nonseptic patients. Overall, this work demonstrates that the inhibition of mitophagy is a physiological mechanism that contributes to the activation of myeloid cells and improves the outcome of sepsis.

Authors

Danish Patoli, Franck Mignotte, Valérie Deckert, Alois Dusuel, Adélie Dumont, Aurélie Rieu, Antoine Jalil, Kevin Van Dongen, Thibaut Bourgeois, Thomas Gautier, Charlène Magnani, Naig Le Guern, Stéphane Mandard, Jean Bastin, Fatima Djouadi, Christine Schaeffer, Nina Guillaumot, Michel Narce, Maxime Nguyen, Julien Guy, Auguste Dargent, Jean-Pierre Quenot, Mickaël Rialland, David Masson, Johan Auwerx, Laurent Lagrost, Charles Thomas

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Figure 2

LPS/IFN-γ–mediated inhibition of mitophagy is associated with metabolic reprogramming of macrophages.

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LPS/IFN-γ–mediated inhibition of mitophagy is associated with metabolic ...
(A and B) Mitochondrial network of (A) mouse peritoneal macrophages or (B) raw 264.7 macrophages exposed to vehicle or LPS/IFN-γ for 6 hours (A) immunostained for Tom20 in combination or not with PINK1 or (B) stained with JC-1 (right panels represent the image binarization of JC-1 stained macrophages). Scale bars: 10 μm. (C) Flow cytometry assessment of mitochondrial density and Δψm in raw 264.7 macrophages exposed to LPS/IFN-γ and stained with JC-1 (n = 3 per time point). (D and E) (D) Oxygen consumption (OCR) and extracellular acidification (ECAR) profile measured with Seahorse XFe96 analyzer on BMDMs exposed to vehicle, LPS/IFN-γ for 6 hours, or mdivi-1 for 24 hours (n = 8 per condition). (F) Flow cytometry assessment of Δψm with TMRM in raw 264.7 macrophages exposed to LPS/IFN-γ for 6 hours (n = 3 per condition). (G) Cell death assessed by low cytometry (annexin V-PI) in raw 264.7 macrophages exposed to vehicle or LPS/IFN-γ and 2,4 DNP alone or in combination for 18 hours. Bar graphs represent mean ± SEM with overlaid individual values; #P < 0.05, ##P < 0.01, ###P < 0.001 determined by ANOVA corrected for multiple comparisons; **P < 0.01, ***P < 0.001 determined by Student’s t test with Welch’s correction. Veh, vehicle.