Dual targeting of Keap1 and Gsk-3 by hexaraphane in the regulation of transcription factor Nrf2

TY - JOUR

T1 - Dual targeting of Keap1 and Gsk-3 by hexaraphane in the regulation of transcription factor Nrf2

AU - García-Yagüe, Ángel J.

AU - Cueto-Díaz, Eduardo J.

AU - Escoll, Maribel

AU - Okunishi, Isao

AU - Hayes, John D.

AU - Rodríguez-Franco, María Isabel

AU - Rojo, Ana I.

AU - Cuadrado, Antonio

N1 - Publisher Copyright: © 2025 The Authors

PY - 2025/11

Y1 - 2025/11

N2 - 6-(Methylsulfinyl)hexyl isothiocyanate, here referred to as hexaraphane, is a bioactive compound found in wasabi, which exhibits cytoprotective, anti-inflammatory, and chemopreventive properties. The beneficial effects of hexaraphane are largely mediated through derepression of transcription factor Nrf2, which is typically repressed via proteasomal degradation mediated by its two-site interaction with the ubiquitin E3 ligase adapter Keap1. Like other isothiocyanates, hexaraphane increases Nrf2 activity by perturbing the Nrf2–Keap1 interaction and stalling Keap1-directed ubiquitination. However, we found that hexaraphane modestly increases Nrf2 levels in Keap1-deficient cells, suggesting an additional Keap1-independent mechanism. Unlike other electrophilic Nrf2 activators, hexaraphane did not significantly impact Erk, p38Mapk, Jnk, or Pten/Pi3k/Akt signaling. Instead, our data reveal that hexaraphane inhibits Gsk-3β, a kinase that targets Nrf2 for proteasomal degradation by phosphorylating a DSGIS degron in the transcription factor through which it interacts with the β-TrCP E3 ligase adaptor. Hexaraphane reduced Nrf2 ubiquitination and its binding to Gsk-3β, mimicking the effects of the Gsk-3β inhibitor SB216763. In vitro kinase assays confirmed that hexaraphane suppresses Nrf2 phosphorylation. Furthermore, simulations of molecular docking and dynamics predict a specific interaction between hexaraphane and the catalytic groove of Gsk-3β. These findings identify hexaraphane as a previously unrecognized dual-acting Nrf2 activator that stabilizes Nrf2 both by disturbing Keap1 binding and by inhibiting Gsk-3β that forms the DSGIpS338 phosphodegron.

AB - 6-(Methylsulfinyl)hexyl isothiocyanate, here referred to as hexaraphane, is a bioactive compound found in wasabi, which exhibits cytoprotective, anti-inflammatory, and chemopreventive properties. The beneficial effects of hexaraphane are largely mediated through derepression of transcription factor Nrf2, which is typically repressed via proteasomal degradation mediated by its two-site interaction with the ubiquitin E3 ligase adapter Keap1. Like other isothiocyanates, hexaraphane increases Nrf2 activity by perturbing the Nrf2–Keap1 interaction and stalling Keap1-directed ubiquitination. However, we found that hexaraphane modestly increases Nrf2 levels in Keap1-deficient cells, suggesting an additional Keap1-independent mechanism. Unlike other electrophilic Nrf2 activators, hexaraphane did not significantly impact Erk, p38Mapk, Jnk, or Pten/Pi3k/Akt signaling. Instead, our data reveal that hexaraphane inhibits Gsk-3β, a kinase that targets Nrf2 for proteasomal degradation by phosphorylating a DSGIS degron in the transcription factor through which it interacts with the β-TrCP E3 ligase adaptor. Hexaraphane reduced Nrf2 ubiquitination and its binding to Gsk-3β, mimicking the effects of the Gsk-3β inhibitor SB216763. In vitro kinase assays confirmed that hexaraphane suppresses Nrf2 phosphorylation. Furthermore, simulations of molecular docking and dynamics predict a specific interaction between hexaraphane and the catalytic groove of Gsk-3β. These findings identify hexaraphane as a previously unrecognized dual-acting Nrf2 activator that stabilizes Nrf2 both by disturbing Keap1 binding and by inhibiting Gsk-3β that forms the DSGIpS338 phosphodegron.

KW - Gsk-3β

KW - Hexaraphane

KW - Keap1

KW - Molecular docking

KW - Molecular dynamics

KW - Nrf2

UR - https://www.scopus.com/pages/publications/105013131920

U2 - 10.1016/j.freeradbiomed.2025.07.051

DO - 10.1016/j.freeradbiomed.2025.07.051

M3 - Article

C2 - 40752636

AN - SCOPUS:105013131920

SN - 0891-5849

VL - 239

SP - 579

EP - 593

JO - Free Radical Biology and Medicine

JF - Free Radical Biology and Medicine

ER -