Cell membrane-penetrating capacity of hPP10-Cu, Zn-SOD fusion protein and its antioxidant and anti-inflammatory activity

Abstract

To investigate the cell membrane-penetrating capacity of human cell-penetrating peptide hPP10 carrying human antioxidant protein Cu-Zn superoxide dismutase (Cu, Zn-SOD) and assess the antioxidant and anti-inflammatory activity of these fusion proteins. The fusion protein hPP10-Cu, Zn-SOD was obtained by genetic engineering and identified by Western blotting. The membrane-penetrating ability of the fusion protein was evaluated by immunofluorescence assay, fluorescence colocalization assay and Western blotting, its SOD enzyme activity was detected using a commercial kit, and its effect on cell viability was assessed with MTT assay. In a HEK293 cell model of H2O2-induced oxidative stress, the effect of hPP10-Cu, Zn-SOD on cell apoptosis was analyzed with flow cytometry and RT-qPCR, and its antioxidant effect was assessed using reactive oxygen species (ROS) assay; its anti-inflammatory effect was evaluated in mouse model of TPA-induced ear inflammation by detecting expression of the inflammatory factors using RT-qPCR, Western blotting and immunohistochemistry. The fusion protein hPP10-Cu, Zn-SOD was successfully obtained. Immunofluorescence assay confirmed obvious membrane penetration of this fusion protein in HEK293 cells, localized both in the cell membrane and the cell nuclei after cell entry. hPP10-Cu, Zn-SOD at the concentration of 5 μmol/L exhibited strong antioxidant activity with minimal impact on cell viability at the concentration up to 10 μmol/L. The fusion protein obviously inhibited apoptosis and decreased intracellular ROS level in the oxidative stress cell model and significantly reduced mRNA and protein expression of the inflammatory factors in the mouse model of ear inflammation. The fusion protein hPP10-Cu, Zn-SOD capable of penetrating the cell membrane possesses strong antioxidant and anti-inflammatory activities with only minimal cytotoxicity, demonstrating the value of hPP10 as an efficient drug delivery vector and the potential of hPP10-Cu, Zn-SOD in the development of skincare products.