Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Dermatology, Taipei Medical University Hospital, Taipei, Taiwan.
Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.
J Dermatol Sci. 2018 Nov;92(2):151-161. doi: 10.1016/j.jdermsci.2018.08.011. Epub 2018 Aug 31.
B lymphocyte-induced maturation protein-1 (BLIMP1) is a transcriptional repressor, and plays a crucial role in the regulation of development and functions of various immune cells. Currently, there is limited understanding about the regulation of BLIMP1 expression in keratinocytes and crosstalk between EGFR and BLIMP1 in skin homeostasis.
The aim of the study was to investigate the regulation and functional link between EGFR and BLIMP1 in human epidermal keratinocytes.
Immunoblotting and Q-PCR were used to determine the molecular mechanism of BLIMP1 expression induced by EGFR in primary human epidermal keratinocytes (NHEK) and HaCaT cells. In functional assay, effects of BLIMP1 knockdown on EGFR-mediated cytokine production, differentiation, and migration in NHEK were evaluated by Q-PCR, ELISA, immunoblotting, and/or wound-healing assay.
EGFR activation by EGFR ligands could upregulate the protein and mRNA levels of BLIMP1 in NHEK and HaCaT cells. This effect was dependent on PKC, p38, and ERK activation. Additionally, the stability of BLIMP1 protein was under the control of the proteasome and lysosome degradation systems. EGF could also upregulate BLIMP1 expression in skin squamous cell carcinomas. In addition, BLIMP1 knockdown enhanced the EGFR-mediated IL8, CXCL5 and IL6 gene expression and keratinocyte migration, but reduced the EGFR-mediated suppression of differentiation marker K10.
Our findings shed new insights into the regulation of BLIMP1 expression by EGFR-mediated gene transcription and proteasome/lysosome-mediated degradation in keratinocytes. Functionally, BLIMP1 is a negative regulator of EGF-induced inflammation and migration in keratinocytes, and exerts a gene-specific regulation on keratinocyte differentiation.
B 淋巴细胞诱导成熟蛋白-1（BLIMP1）是一种转录抑制因子，在调节各种免疫细胞的发育和功能方面发挥着关键作用。目前，人们对表皮角质形成细胞中 BLIMP1 表达的调控以及 EGFR 和 BLIMP1 在皮肤稳态中的相互作用知之甚少。
本研究旨在探讨 EGFR 对人表皮角质形成细胞（NHEK）和 HaCaT 细胞中 BLIMP1 表达的调控及其功能联系。
采用免疫印迹和 Q-PCR 法检测 EGFR 配体激活 EGFR 诱导 NHEK 和 HaCaT 细胞中 BLIMP1 表达的分子机制。在功能测定中，通过 Q-PCR、ELISA、免疫印迹和/或划痕愈合试验评估 BLIMP1 敲低对 NHEK 中 EGFR 介导的细胞因子产生、分化和迁移的影响。
EGFR 配体激活 EGFR 可上调 NHEK 和 HaCaT 细胞中 BLIMP1 的蛋白和 mRNA 水平。这种效应依赖于 PKC、p38 和 ERK 的激活。此外，BLIMP1 蛋白的稳定性受蛋白酶体和溶酶体降解系统的控制。EGF 还可上调皮肤鳞状细胞癌中 BLIMP1 的表达。此外，BLIMP1 敲低增强了 EGFR 介导的 IL8、CXCL5 和 IL6 基因表达和角质形成细胞迁移，但降低了 EGFR 介导的分化标志物 K10 的抑制作用。
我们的研究结果为 EGFR 介导的基因转录和蛋白酶体/溶酶体介导的角质形成细胞中 BLIMP1 表达的调控提供了新的见解。功能上，BLIMP1 是角质形成细胞中 EGF 诱导的炎症和迁移的负调节剂，并对角质形成细胞分化具有基因特异性调节作用。
