TY - JOUR
T1 - Nrf2 signaling modulates cigarette smoke-induced complement activation in retinal pigmented epithelial cells
AU - Wang, Lei
AU - Kondo, Naoshi
AU - Cano, Marisol
AU - Ebrahimi, Katayoon
AU - Yoshida, Takeshi
AU - Barnett, Bradley P.
AU - Biswal, Shyam
AU - Handa, James T.
N1 - Funding Information:
We thank Mike Sporn, M.D., Dartmouth School of Medicine, for providing CDDO-Im. This work was supported by EY14005 (J.T.H.), EY019904 (J.T.H.), P50HL107169 (S.B.), R01CA140492 (S.B.), a Thome Foundation Award in AMD (J.T.H.), a Research to Prevent Blindness Senior Scientist Award (J.T.H.), a Wilmer Core Grant, EY001765, an unrestricted grant from Research to Prevent Blindness, and gifts from the Merlau family and Aleda Wright. J.T.H. is a Robert Bond Welch Professor.
PY - 2014/5
Y1 - 2014/5
N2 - Whereas cigarette smoking (CS) and dysregulated complement are thought to play central roles in age-related macular degeneration (AMD), their exact roles are unknown. The aim of this study was to determine if CS activates complement and if the antioxidant transcription factor Nrf2 modulates this response. In AMD specimens, Nrf2 immunolabeling was strong in the cytoplasm, with scattered nuclear labeling of macular retinal pigmented epithelial (RPE) cells that appeared normal, but was decreased and without nuclear labeling in dysmorphic cells overlying drusen, a hallmark AMD lesion. Cigarette smoke extract (CSE) induced Nrf2 nuclear translocation in RPE cells with increased antioxidant and complement gene expression. Whereas CFH protein was not altered by CSE, the cell membrane regulator proteins CD46, CD55, and CD59 were decreased, and C3a and C3b, but not iC3b, were increased compared to controls. C5b-9 was increased by CSE, but at sublytic levels, only after addition of normal human serum. Nrf2 knockdown enhanced the increase in C3a and C3b from CSE, but not iC3b, C5a, or C5b-9. CSE also increased IL-1b expression and secretion after C3a generation and was reduced by a C3aR antagonist. In contrast, the Nrf2 activator CDDO-Im restored complement gene expression in RPE cells exposed to CSE. We provide evidence of altered Nrf2 in human AMD and that CSE induces a proinflammatory environment specifically by generating C3a and C3b, and Nrf2 deficiency magnifies this specific complement response.
AB - Whereas cigarette smoking (CS) and dysregulated complement are thought to play central roles in age-related macular degeneration (AMD), their exact roles are unknown. The aim of this study was to determine if CS activates complement and if the antioxidant transcription factor Nrf2 modulates this response. In AMD specimens, Nrf2 immunolabeling was strong in the cytoplasm, with scattered nuclear labeling of macular retinal pigmented epithelial (RPE) cells that appeared normal, but was decreased and without nuclear labeling in dysmorphic cells overlying drusen, a hallmark AMD lesion. Cigarette smoke extract (CSE) induced Nrf2 nuclear translocation in RPE cells with increased antioxidant and complement gene expression. Whereas CFH protein was not altered by CSE, the cell membrane regulator proteins CD46, CD55, and CD59 were decreased, and C3a and C3b, but not iC3b, were increased compared to controls. C5b-9 was increased by CSE, but at sublytic levels, only after addition of normal human serum. Nrf2 knockdown enhanced the increase in C3a and C3b from CSE, but not iC3b, C5a, or C5b-9. CSE also increased IL-1b expression and secretion after C3a generation and was reduced by a C3aR antagonist. In contrast, the Nrf2 activator CDDO-Im restored complement gene expression in RPE cells exposed to CSE. We provide evidence of altered Nrf2 in human AMD and that CSE induces a proinflammatory environment specifically by generating C3a and C3b, and Nrf2 deficiency magnifies this specific complement response.
KW - Aging-related disease
KW - Complement
KW - Free radicals
KW - Innate immunity
KW - Nrf2
KW - Oxidative stress
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U2 - 10.1016/j.freeradbiomed.2014.01.015
DO - 10.1016/j.freeradbiomed.2014.01.015
M3 - Article
C2 - 24440594
AN - SCOPUS:84896443276
SN - 0891-5849
VL - 70
SP - 155
EP - 166
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
ER -