Polypeptide from Chlamys farreri suppresses ultraviolet-B irradiation-induced apoptosis through restoring ER redox homeostasis, scavenging ROS generation, and suppressing the PERK-eIF2a-CHOP pathway in HaCaT cells

• PCF increases cell viability in HaCaT cells following UVB irradiation.
• PCF protects HaCaT cells against UVB irradiation-induced apoptosis.
• PCF restores ER redox homeostasis in HaCaT cells following UVB irradiation.
• PCF scavenges ROS generation in HaCaT cells following UVB irradiation.
• PCF suppresses PERK-eIF2a-CHOP pathway in UVB-irradiated HaCaT cells.

ObjectiveThe aim of this study was to investigate the effect of polypeptide from Chlamys farreri (PCF) on ultraviolet B (UVB) irradiation-induced apoptosis in human keratinocyte HaCaT cells.MethodsHaCaT cells were treated with 20 mJ/cm2 UVB irradiation for 18 h. The cell viability was measured by MTT assay, and apoptosis was detected with Hoechst 33258 staining and caspase-3 activity detection. Protein expression levels were assessed by Western blot analysis, and the intracellular ROS levels were also measured.ResultsOur results from the MTT assay showed that UVB irradiation significantly declined the viability of HaCaT cells, which could be restored by PCF treatment. PCF decreased the apoptosis rate in HaCaT cells treated with UVB irradiation. Moreover, PCF increased the expression levels of PDI and Ero-1a, and scavenged the intracellular ROS. Furthermore, PCF inhibited the expressions of GRP78, p-PERK, p-eIF2a, and CHOP, and suppressed the ER stress-induced apoptosis, in UVB-irradiated HaCaT cells. In addition, the ROS scavenging effect of 4-PBA was less potent than PCF, indicating that ER stress-related ROS production contribute partially to the total ROS level, and ER was not the only target of PCF treatment.ConclusionsOur results indicate that PCF inhibits UVB irradiation-induced apoptosis through restoring ER redox homeostasis and suppressing the PERK-eIF2a-CHOP pathway. These findings provide evidence for the application of PCF in the protection of skin from UV irradiation.