Mitochondrial C5aR1 activity in macrophages controls IL-1β production underlying sterile inflammation

TY - JOUR

T1 - Mitochondrial C5aR1 activity in macrophages controls IL-1β production underlying sterile inflammation

AU - Niyonzima, Nathalie

AU - Rahman, Jubayer

AU - Kunz, Natalia

AU - West, Erin E.

AU - Freiwald, Tilo

AU - Desai, Jigar V.

AU - Merle, Nicolas S.

AU - Gidon, Alexandre

AU - Sporsheim, Bjørnar

AU - Lionakis, Michail S.

AU - Evensen, Kristin

AU - Lindberg, Beate

AU - Skagen, Karolina

AU - Skjelland, Mona

AU - Singh, Parul

AU - Haug, Markus

AU - Ruseva, Marieta M.

AU - Kolev, Martin

AU - Bibby, Jack

AU - Marshall, Olivia

AU - O’Brien, Brett

AU - Deeks, Nigel

AU - Afzali, Behdad

AU - Clark, Richard J.

AU - Woodruff, Trent M.

AU - Pryor, Milton

AU - Yang, Zhi-Hong

AU - Remaley, Alan T.

AU - Mollnes, Tom E.

AU - Hewitt, Stephen M.

AU - Yan, Bingyu

AU - Kazemian, Majid

AU - Kiss, Máté G.

AU - Binder, Christoph J.

AU - Halvorsen, Bente

AU - Espevik, Terje

AU - Kemper, Claudia

PY - 2021/12/24

Y1 - 2021/12/24

N2 - While serum-circulating complement destroys invading pathogens, intracellularly active complement, termed the “complosome,” functions as a vital orchestrator of cell-metabolic events underlying T cell effector responses. Whether intracellular complement is also nonredundant for the activity of myeloid immune cells is currently unknown. Here, we show that monocytes and macrophages constitutively express complement component (C) 5 and generate autocrine C5a via formation of an intracellular C5 convertase. Cholesterol crystal sensing by macrophages induced C5aR1 signaling on mitochondrial membranes, which shifted ATP production via reverse electron chain flux toward reactive oxygen species generation and anaerobic glycolysis to favor IL-1β production, both at the transcriptional level and processing of pro–IL-1β. Consequently, atherosclerosis-prone mice lacking macrophage-specific C5ar1 had ameliorated cardiovascular disease on a high-cholesterol diet. Conversely, inflammatory gene signatures and IL-1β produced by cells in unstable atherosclerotic plaques of patients were normalized by a specific cell-permeable C5aR1 antagonist. Deficiency of the macrophage cell-autonomous C5 system also protected mice from crystal nephropathy mediated by folic acid. These data demonstrate the unexpected intracellular formation of a C5 convertase and identify C5aR1 as a direct modulator of mitochondrial function and inflammatory output from myeloid cells. Together, these findings suggest that the complosome is a contributor to the biologic processes underlying sterile inflammation and indicate that targeting this system could be beneficial in macrophage-dependent diseases, such as atherosclerosis.

AB - While serum-circulating complement destroys invading pathogens, intracellularly active complement, termed the “complosome,” functions as a vital orchestrator of cell-metabolic events underlying T cell effector responses. Whether intracellular complement is also nonredundant for the activity of myeloid immune cells is currently unknown. Here, we show that monocytes and macrophages constitutively express complement component (C) 5 and generate autocrine C5a via formation of an intracellular C5 convertase. Cholesterol crystal sensing by macrophages induced C5aR1 signaling on mitochondrial membranes, which shifted ATP production via reverse electron chain flux toward reactive oxygen species generation and anaerobic glycolysis to favor IL-1β production, both at the transcriptional level and processing of pro–IL-1β. Consequently, atherosclerosis-prone mice lacking macrophage-specific C5ar1 had ameliorated cardiovascular disease on a high-cholesterol diet. Conversely, inflammatory gene signatures and IL-1β produced by cells in unstable atherosclerotic plaques of patients were normalized by a specific cell-permeable C5aR1 antagonist. Deficiency of the macrophage cell-autonomous C5 system also protected mice from crystal nephropathy mediated by folic acid. These data demonstrate the unexpected intracellular formation of a C5 convertase and identify C5aR1 as a direct modulator of mitochondrial function and inflammatory output from myeloid cells. Together, these findings suggest that the complosome is a contributor to the biologic processes underlying sterile inflammation and indicate that targeting this system could be beneficial in macrophage-dependent diseases, such as atherosclerosis.

UR - https://doi.org/10.1126/sciimmunol.abf2489

U2 - 10.1126/sciimmunol.abf2489

DO - 10.1126/sciimmunol.abf2489

M3 - SCORING: Journal article

C2 - 34932384

VL - 6

SP - eabf2489

JO - SCI IMMUNOL

JF - SCI IMMUNOL

SN - 2470-9468

IS - 66

M1 - eabf2489

ER -