Small molecule activators of the Nrf2-HO-1 antioxidant axis modulate heme metabolism and inflammation in BV2 microglia cells.
The nuclear factor erythroid derived 2-related factor 2 (Nrf2) and the antioxidant protein heme oxygenase-1 (HO-1) are crucial components of the cellular stress response. These two systems work together to combat oxidative stress and inflammation and are attractive drug targets for counteracting different pathologies, including neuroinflammation. We aimed to identify the most effective Nrf2/HO-1 activators that modulate the inflammatory response in microglia cells. In the present study, we searched the literature and selected 56 compounds reported to activate Nrf2 or HO-1 and analyzed them for HO-1 induction at 6 and 24h and cytotoxicity in BV2 microglial cells in vitro. Approximately 20 compounds up-regulated HO-1 at the concentrations tested (5-20 μM) with carnosol, supercurcumin, cobalt protoporphyrin-IX and dimethyl fumarate exhibiting the best induction/low cytotoxicity profile. Up-regulation of HO-1 by some compounds resulted in increased cellular bilirubin levels but did not augment the expression of proteins involved in heme synthesis (ALAS 1) or biliverdin reductase. Bilirubin production by HO-1 inducers correlated with their potency in inhibiting nitrite production after challenge with interferon-γ (INF-γ) or lipopolysaccharide (LPS). The compounds down-regulated the inflammatory response (TNF-α, PGE2 and nitrite) more strongly in cells challenged with INF-γ than LPS, and silencing HO-1 or Nrf2 with shRNA differentially affected the levels of inflammatory markers. These findings indicate that some small activators of Nrf2/HO-1 are effective modulators of microglia inflammation and highlight the chemical scaffolds that can serve for the synthesis of potent new derivatives to counteract neuroinflammation and neurodegeneration.
Université Paris-Est, UMR_S955, UPEC, F-94000 Créteil, France; Inserm U955, Equipe 3, F-94000 Créteil, France. Electronic address: roberta.foresti@inserm.fr.
Roberta
R
Foresti
Sandip K
SK
Bains
Tamil Selvi
TS
Pitchumony
Lisandra E
LE
de Castro Brás
Filippo
F
Drago
Jean-Luc
JL
Dubois-Randé
Claudio
C
Bucolo
Roberto
R
Motterlini
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001663:Bilirubin / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006418:Heme / Q000378:metabolism*; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D007249:Inflammation / Q000188:drug therapy / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology; D051379:Mice; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000276:immunology / Q000378:metabolism*; D054852:Small Molecule Libraries / Q000737:chemistry* / Q000494:pharmacology*
D000975:Antioxidants; D008070:Lipopolysaccharides; D051267:NF-E2-Related Factor 2; C495636:Nfe2l2 protein, mouse; D054852:Small Molecule Libraries; D006418:Heme; D007371:Interferon-gamma; D051547:Heme Oxygenase-1; D001663:Bilirubin
2,2-dihydroxychalcone; ALAS 1; ARE; BV2 microglia; BVR; CA; CAA; CO-RMs; CoPP; DHC; DMF; H; HF-E2 p45-related factor 2; HO-1; Heme metabolism; INF-γ; ISL; Inflammation; Keap-1; Kelch-like ECH-associated protein-1; LPS; Nrf2; PGE2; S; SC; Small molecule activators; SnPPIX; TNF-α; antioxidant responsive element; biliverdin reductase; carbon monoxide-releasing molecules; carnosic acid; carnosol; cobalt protoporphyrin IX; delta-aminolevulinate synthase 1; dimethyl fumarate; heme oxygenase-1; hemin; interferon-γ; isoliquiritigenin; lipopolysaccharide; prostglandin E2; shRNA; small hairpin RNA; sulforaphane; supercurcumin; tBH; tert-butyl hydroquinone; tin protoporphyrin IX; tumor necrosis factor alpha