Identification of Ketoconazole as an AhR-Nrf2 Activator in Cultured Human Keratinocytes: The Basis of Its Anti-Inflammatory Effect

Abstract

Ketoconazole (KCZ) has been shown to exhibit anti-inflammatory effects in addition to its inhibitory effects against fungi; however, the underlying molecular mechanism remains poorly understood. Aryl hydrocarbon receptor (AhR), a receptor that is activated by polycyclic aromatic hydrocarbons (PAHs) and halogenated aromatic hydrocarbons such as dioxin, is a sensor of the redox system against oxidative stress and regulates nuclear factor-erythroid 2-related factor-2 (Nrf2), a master switch of the redox machinery. To clarify whether KCZ modulates AhR-Nrf2 function leading to redox system activation, cultured human keratinocytes were treated with KCZ. Confocal microscopic analysis revealed that KCZ induced AhR nuclear translocation, resulting in the upregulation of CYP1A1 mRNA and protein expression. Furthermore, KCZ actively switched on Nrf2 nuclear translocation and quinone oxidoreductase 1 expression. Tumor necrosis factor-α- and benzo(a)pyrene (BaP)-induced reactive oxidative species (ROS) and IL-8 production were effectively inhibited by KCZ. Knockdown of either AhR or Nrf2 abolished the inhibitory capacity of KCZ on ROS and IL-8 production. In addition, KCZ-induced Nrf2 activation was canceled by AhR knockdown. Moreover, KCZ inhibited BaP-induced 8-hydroxydeoxyguanosine and IL-8 production. In conclusion, the engagement of AhR by KCZ exhibits the cytoprotective effect mediated by the Nrf2 redox system, which potently downregulates either cytokine-induced (AhR-independent) or PAH-induced (AhR-dependent) oxidative stress.

Coal tar induces AHR-dependent skin barrier repair in atopic dermatitis

“…We therefore hypothesized that the molecular mechanism of coal tar-mediated inhibition of STAT6 phosphorylation could, at least in part, act via inhibition of the oxidative inactivation of PTPN1. AHR is known as a sensor of the redox system against oxidative stress and regulates nuclear factor erythroid 2-related factor 2 (NRF2), a master switch of the redox machinery (26). We found coal tar to induce both nuclear translocation of NRF2 ( Figure 5B) and subsequent induction of its target gene, NAD(P)H quinone oxidoreductase 1 (NQO1) in keratinocytes ( Figure 5C).…”

Aryl Hydrocarbon Receptor Mediates Indoxyl Sulfate-Induced Cellular Senescence in Human Umbilical Vein Endothelial Cells

“…We therefore examined whether AhR mediates IS-induced endothelial senescence using AhR inhibitors. The blockade of AhR by its inhibitors canceled the observed cellular senescence in association with the restoration of the iNampt activity, NAD 61) , suggesting that AhR signaling may be important as a biological defense mechanism. In view of these reports, the complete blockade of the IS-AhR pathway may result in adverse effects in various organs, including the vasculature; therefore, further investigation is required to explore the physiological effects of the AhR signaling pathway on different tissues and cells.…”

Deficits in Bioenergetics and Impaired Immune Response in Granulocytes From Children With Autism

“…In search of a common mechanism that would explain the above results, we focused on NFE2L2 because this nuclear transcription factor regulates clusters of genesthatcontrolcellularantioxidants, [39][40][41] modulate both innate and adaptive immune responses, 42 and has a strong association with mitochondrial function, glucose and fatty acid homeostasis, and immune response via peroxisome proliferator-activated receptor g (PPARg). [43][44][45][46] Consistent with this hypothesis, the transcript levels of NFE2L2 (normalized to glyceraldehyde 3-phosphate dehydrogenase [GAPDH]) evaluated by quantitative polymerase chain reaction were 45% of those of TD children (Table 1).…”