Li Yadi, Zhou Xiaoqian, Yang Zhusheng, Zhang Lichao, Yang Xiumin, Wei Aihua
Department of Dermatology, Beijing Tongren Hospital, Capital Medical University, No.1 Dongjiaomin Lane, Dongcheng District, Beijing, 100730, China.
Curr Mol Med. 2024 Aug 9. doi: 10.2174/0115665240296144240419063309.
Ferroptosis of keratinocytes is closely associated with amplification of skin inflammation in psoriasis. This study focuses on unlocking the role of caffeic acid (CA), a polyphenol compound, in keratinocyte ferroptosis and understanding the underlying mechanistic basis.
The interaction between early growth response protein 1 (EGR1) and chac glutathione specific γ‑glutamylcyclotransferase 1 (CHAC1) was predicted by bioinformatics and validated via chromatin immunoprecipitation and dual-luciferase reported assays. Their expressions in primary human epidermal keratinocytes were altered by transfection of EGR1/CHAC1 overexpression or knockdown plasmids, and then keratinocytes were followed by CA treatment and Erastin (ferroptosis inducer). Keratinocyte viability was determined by CCK-8 assay, and the ferroptotic effect was evaluated using colorimetric assay and flow cytometry. Proinflammatory cytokine secretion by keratinocytes was detected via ELISA. Expressions of EGR1 and CHAC1 in keratinocytes were analyzed by qRT-PCR or Western blot.
Increased expressions of EGR1 and CHAC1 were detected in keratinocytes with Erastin treatment. CA (100 μM) antagonized Erastin (10 μM)-induced decrease in viability, increases in EGR1 and CHAC1 expressions, upregulation of MDA, ROS, and Fe2+, downregulation of GSH and SOD, and secretion of proinflammatory cytokines from keratinocytes. EGR1 overexpression potentiated Erastin-induced effects. Moreover, EGR1 overexpression and CA mutually counteracted their effects on Erastin-induced keratinocytes. EGR1 transcriptionally activated and positively regulated CHAC1. The above Erastin-induced effects were neutralized by EGR1 knockdown but potentiated by CHAC1 overexpression. Moreover, EGR1 knockdown and CHAC1 overexpression reversed each other's effects.
CA reduces ferroptosis by inhibiting EGR1-induced activation of CHAC1 to dampen inflammation of keratinocytes in psoriasis. This study providing new compounds and candidate targets for the clinical treatment of psoriasis.
角质形成细胞的铁死亡与银屑病皮肤炎症的加剧密切相关。本研究着重于揭示多酚化合物咖啡酸（CA）在角质形成细胞铁死亡中的作用，并了解其潜在的机制基础。
通过生物信息学预测早期生长反应蛋白1（EGR1）与查克谷胱甘肽特异性γ-谷氨酰环转移酶1（CHAC1）之间的相互作用，并通过染色质免疫沉淀和双荧光素酶报告基因检测进行验证。通过转染EGR1/CHAC1过表达或敲低质粒改变它们在原代人表皮角质形成细胞中的表达，然后用CA处理角质形成细胞并加入埃拉斯汀（铁死亡诱导剂）。通过CCK-8检测法测定角质形成细胞活力，使用比色法和流式细胞术评估铁死亡效应。通过酶联免疫吸附测定法检测角质形成细胞分泌的促炎细胞因子。通过qRT-PCR或蛋白质免疫印迹法分析角质形成细胞中EGR1和CHAC1的表达。
在经埃拉斯汀处理的角质形成细胞中检测到EGR1和CHAC1表达增加。CA（100μM）拮抗埃拉斯汀（10μM）诱导的活力降低、EGR1和CHAC1表达增加、丙二醛（MDA）、活性氧（ROS）和铁离子（Fe2+）上调、谷胱甘肽（GSH）和超氧化物歧化酶（SOD）下调以及角质形成细胞促炎细胞因子的分泌。EGR1过表达增强了埃拉斯汀诱导的效应。此外，EGR1过表达和CA相互抵消了它们对埃拉斯汀诱导的角质形成细胞的影响。EGR1转录激活并正向调节CHAC1。上述埃拉斯汀诱导的效应被EGR1敲低所中和，但被CHAC1过表达所增强。此外，EGR1敲低和CHAC1过表达相互逆转彼此的效应。
CA通过抑制EGR1诱导的CHAC1激活来减少铁死亡，从而减轻银屑病中角质形成细胞的炎症。本研究为银屑病的临床治疗提供了新的化合物和候选靶点。
