Paeoniflorin regulates RhoA/ROCK1 and Nrf2 pathways in PDLIM1-dependent or independent manners in oxidative stressed melanocytes

Abstract

Background: The adhesive properties of vitiligo melanocytes have decreased under oxidative stress., cytoskeleton proteins can control cell adhesion. Paeoniflorin (PF) was proved to resist hydrogen peroxide (H₂O₂)-induced oxidative stress in melanocytes via nuclear factorE2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway.

Objectives: This study was to investigate whether PF exerts anti-oxidative effect through influencing cytoskeleton markers or potential signaling pathway.

Methods: Human Oxidative Stress Plus array was used to identify the differentially expressed genes between H₂O₂ + PF group and H₂O₂ only group, in PIG1 and PIG3V melanocyte cell lines respectively. Western blotting was used to verify the PCR array results and to test the protein expression levels of cytoskeleton markers including Ras homolog family member A (RhoA), Rho-associated kinase 1 (ROCK1) and antioxidative marker Nrf2. Small interfering RNA was used to knock down PDZ and LIM domain 1 (PDLIM1).

Results: PF increased the expressions of PDLIM1, RhoA and ROCK1 in H₂O₂-induced PIG1, in contrast, decreased the expressions of PDLIM1 and ROCK1 in H₂O₂-induced PIG3V. Knockdown of PDLIM1 increased the expressions of RhoA and Nrf2 in PF-pretreated H₂O₂-induced PIG1, and ROCK1 and Nrf2 in PF-pretreated H₂O₂-induced PIG3V.

Conclusions: PF regulates RhoA/ROCK1 and Nrf2 pathways in PDLIM1-dependent or independent manners in H₂O₂-induced melanocytes. In PIG1, PF promotes PDLIM1 to inhibit RhoA/ROCK1 pathway or activates Nrf2/HO-1 pathway, separately. In PIG3V, PF directly downregulates ROCK1 in PDLIM1-independent manner or upregulates Nrf2 dependent of PDLIM1.

Keywords: Cytoskeleton; PDLIM1; Paeoniflorin; ROCK1; RhoA; Vitiligo.