4-Octyl Itaconate Improves the Viability of D66H Cells by Regulating the KEAP1-NRF2-GCLC/HO-1 Pathway

As a novel nuclear factor E2-related factor 2 (NRF2) activator, the itaconate has shown significant therapeutic potential for oxidative stress diseases. However, its role in Vohwinkel syndrome in relation to the gap junction protein beta 2 (GJB2) mutation is still unclear. This study aimed at investigating the effect of 4-octyl itaconate (OI) on HaCaT and D66H cells and clarify its potential mechanism in vitro. The optimal concentration and treatment time of OI on HaCaT cells and D66H cells were determined by CCK-8 and LDH experiments. The effect of OI on cell proliferation was detected by EdU staining and FACS analysis of PI, while the apoptosis was evaluated by TUNEL staining and FACS analysis of Annexin V. The ROS staining was performed, and the levels of SOD, MDA, GSH and GSH/GSSG were detected to evaluate the effect of OI on oxidative damage induced by D66H-type mutation. CO-IP, Western blot, immunofluorescence and qPCR analyses were employed to detect the activation of KEAP1-NRF2-GCLC/HO-1 pathway by OI. Finally, sh-NRF2 was used to confirm the activation of this pathway by OI. Results showed that OI could improve the cell viability decreased by GJB2 gene mutation by regulating the balance between cell growth and apoptosis induced by oxidative damage. Furthermore, this alleviation process was regulated by the KEAP1-NRF2-HO-1/GCLC pathway. In conclusion, OI could improve the viability of HaCaT and D66H cells via regulating the KEAP1-NRF2-GCLC/HO-1 pathway, which provided a wide spectrum of potential targets for effective therapeutic treatments of Vohwinkel syndrome in the clinic.