Transcriptome Analysis of the Protective Mechanism of Ectoine on Human Skin Keratinocytes

Introduction: Ectoine, a natural protective agent produced by halophilic bacteria, demonstrates remarkable skin-protective efficacy; however, the precise molecular mechanisms underlying its effects on skin cells remain poorly understood. This study investigated the differentially expressed genes (DEGs) in human keratinocytes (HaCaT) treated with ectoine to clarify its protective mechanisms. Methods: Cell viability was evaluated using the CCK-8 assay, identifying 0.2 mg/mL as the optimal ectoine concentration. A control group (C, 0 mg/mL) and an ectoine group (E, 0.2 mg/mL) were established. Flow cytometry quantified reactive oxygen species (ROS) and apoptosis. Illumina HiSeq RNA-seq identified DEGs; selected genes were validated by RT-qPCR. Results: Ectoine at 0.2 mg/mL increased cell viability to 134.0 % ± 3.2. Compared with the control group, ectoine significantly reduced the apoptosis rate and intracellular ROS levels (P ≤ 0.05). RNA-seq (n = 3) identified 292 DEGs (87 up-regulated, 205 down-regulated). Among them, MMP25, NOXO1, ANGPTL4, and FoXO6—genes involved in oxidative stress, apoptosis, and proliferation—were markedly down-regulated, suggesting enhanced proliferation and anti-oxidative, anti-apoptotic effects. The cell-adhesion gene CNFN was significantly up-regulated, potentially reducing mechanical damage. Conclusion: Ectoine serves as a potent stabilizer and protectant, safeguarding skin by modulating genes that regulate oxidative stress, proliferation, and apoptosis.