TY - JOUR
T1 - NADPH oxidase activation regulates apoptotic neutrophil clearance by murine macrophages
AU - Bagaitkar, Juhi
AU - Huang, Jing
AU - Zeng, Melody Yue
AU - Pech, Nancy K.
AU - Monlish, Darlene A.
AU - Perez-Zapata, Lizet J.
AU - Miralda, Irina
AU - Schuettpelz, Laura G.
AU - Dinauer, Mary C.
N1 - Publisher Copyright:
© 2018 by The American Society of Hematology.
PY - 2018/5/24
Y1 - 2018/5/24
N2 - The phagocyte reduced NAD phosphate (NADPH) oxidase generates superoxide, the precursor to reactive oxygen species (ROS) that has both antimicrobial and immunoreg-ulatory functions. Inactivating mutations in NADPH oxidase alleles cause chronic granulomatous disease (CGD), characterized by enhanced susceptibility to life-threatening microbial infections and inflammatory disorders; hypomorphic NADPH oxidase alleles are associated with autoimmunity. Impaired apoptotic cell (AC) clearance is implicated as an important contributing factor in chronic inflammation and autoimmunity, but the role of NADPH oxidase–derived ROS in this process is incompletely understood. Here, we demonstrate that phagocytosis of AC (efferocytosis) potently activated NADPH oxidase in mouse peritoneal exudate macrophages (PEMs). ROS generation was dependent on macrophage CD11b, Toll-like receptor 2 (TLR2), TLR4, and myeloid differentiation primary response 88 (MyD88), and was also regulated by phosphatidylinositol 3-phosphate binding to the p40phox oxidase subunit. Maturation of efferosomes containing apoptotic neutrophils was significantly delayed in CGD PEMs, including acidification and acquisition of proteolytic activity, and was associated with slower digestion of apoptotic neutrophil proteins. Treatment of wild-type macrophages with the vacuolar-type H1 ATPase inhibitor bafilomycin also delayed proteolysis within efferosomes, showing that luminal acidification was essential for efficient digestion of efferosome proteins. Finally, cross-presentation of AC-associated antigens by CGD PEMs to CD8 T cells was increased. These studies unravel a key role for the NADPH oxidase in the disposal of ACs by inflammatory macrophages. The oxidants generated promote efferosome maturation and acidification that facilitate the degradation of ingested ACs. (Blood.
AB - The phagocyte reduced NAD phosphate (NADPH) oxidase generates superoxide, the precursor to reactive oxygen species (ROS) that has both antimicrobial and immunoreg-ulatory functions. Inactivating mutations in NADPH oxidase alleles cause chronic granulomatous disease (CGD), characterized by enhanced susceptibility to life-threatening microbial infections and inflammatory disorders; hypomorphic NADPH oxidase alleles are associated with autoimmunity. Impaired apoptotic cell (AC) clearance is implicated as an important contributing factor in chronic inflammation and autoimmunity, but the role of NADPH oxidase–derived ROS in this process is incompletely understood. Here, we demonstrate that phagocytosis of AC (efferocytosis) potently activated NADPH oxidase in mouse peritoneal exudate macrophages (PEMs). ROS generation was dependent on macrophage CD11b, Toll-like receptor 2 (TLR2), TLR4, and myeloid differentiation primary response 88 (MyD88), and was also regulated by phosphatidylinositol 3-phosphate binding to the p40phox oxidase subunit. Maturation of efferosomes containing apoptotic neutrophils was significantly delayed in CGD PEMs, including acidification and acquisition of proteolytic activity, and was associated with slower digestion of apoptotic neutrophil proteins. Treatment of wild-type macrophages with the vacuolar-type H1 ATPase inhibitor bafilomycin also delayed proteolysis within efferosomes, showing that luminal acidification was essential for efficient digestion of efferosome proteins. Finally, cross-presentation of AC-associated antigens by CGD PEMs to CD8 T cells was increased. These studies unravel a key role for the NADPH oxidase in the disposal of ACs by inflammatory macrophages. The oxidants generated promote efferosome maturation and acidification that facilitate the degradation of ingested ACs. (Blood.
UR - http://www.scopus.com/inward/record.url?scp=85047877113&partnerID=8YFLogxK
U2 - 10.1182/blood-2017-09-809004
DO - 10.1182/blood-2017-09-809004
M3 - Article
C2 - 29618478
AN - SCOPUS:85047877113
SN - 0006-4971
VL - 131
SP - 2367
EP - 2378
JO - Blood
JF - Blood
IS - 21
ER -