Aidoukovitch Alexandra, Bodahl Sara, Tufvesson Ellen, Nilsson Bengt-Olof
Department of Experimental Medical Science, Lund University, Lund, Sweden.
Folktandvården Skåne, Lund, Sweden.
Int J Dent. 2022 Dec 17;2022:3194703. doi: 10.1155/2022/3194703. eCollection 2022.
The aim of this study was to investigate if desquamated oral epithelial cells (DOECs) express the epidermal growth factor (EGF) and if these cells thereby may contribute to salivary EGF contents.
DOECs have recently been shown to harbor the antimicrobial peptide LL-37, proposing that they may also store other biologically important salivary peptides/proteins. The EGF peptide is a growth factor which plays a critical role to maintain epithelial integrity and promote epithelial healing. The EGF is produced by salivary glands, but it is not known whether DOECs contain the EGF and thereby contribute to salivary EGF levels.
DOECs were isolated from unstimulated whole saliva collected from four healthy volunteers. EGF protein expression was determined in cell lysates by dot blot and ELISA. Cellular distribution of cytokeratin, the proliferation marker Ki67, and EGF immunoreactivity were assessed by immunocytochemistry. EGF gene expression was investigated by qPCR. Expression of EGF transcript and protein in DOECs was compared to that in the human cultured keratinocyte cell line (HaCaT) cells.
EGF protein expression was detected in DOEC cell lysates by both dot blot and ELISA. Strong cytoplasmic EGF immunoreactivity was observed in DOECs, although some cells showed only a weak immunoreactive signal for EGF. Moreover, DOECs, besides containing EGF protein, also expressed transcript for EGF. Interestingly, ELISA analysis revealed that EGF protein contents were higher in DOECs than in HaCaT cells. ELISA analysis also disclosed that EGF concentration was about 10 times higher in whole saliva compared to DOECs. EGF transcript expression was about 50% lower in HaCaT cells stimulated with high (10%) compared to low (0.1%) concentration of fetal bovine serum, representing growth-stimulated and growth-restricted conditions, respectively, implying that growth-stimulus exerts negative feedback on EGF gene activity in HaCaT cells.
Here, we show for the first time that DOECs express the EGF, arguing that these cells contribute to salivary EGF contents and hence may play a role in gingival epithelial repair and wound healing.
本研究旨在调查脱落的口腔上皮细胞（DOECs）是否表达表皮生长因子（EGF），以及这些细胞是否因此可能对唾液中EGF的含量有贡献。
最近有研究表明DOECs含有抗菌肽LL-37，这表明它们也可能储存其他具有生物学重要性的唾液肽/蛋白质。EGF肽是一种生长因子，在维持上皮完整性和促进上皮愈合方面起着关键作用。EGF由唾液腺产生，但尚不清楚DOECs是否含有EGF并因此对唾液中EGF水平有贡献。
从四名健康志愿者未刺激的全唾液中分离出DOECs。通过斑点印迹和酶联免疫吸附测定（ELISA）确定细胞裂解物中EGF蛋白的表达。通过免疫细胞化学评估细胞角蛋白、增殖标志物Ki67和EGF免疫反应性的细胞分布。通过定量聚合酶链反应（qPCR）研究EGF基因表达。将DOECs中EGF转录本和蛋白的表达与人类培养的角质形成细胞系（HaCaT）细胞中的表达进行比较。
通过斑点印迹和ELISA在DOEC细胞裂解物中均检测到EGF蛋白表达。在DOECs中观察到强烈的细胞质EGF免疫反应性，尽管一些细胞对EGF仅显示出微弱的免疫反应信号。此外，DOECs除了含有EGF蛋白外，还表达EGF转录本。有趣的是，ELISA分析显示DOECs中EGF蛋白含量高于HaCaT细胞。ELISA分析还表明，全唾液中EGF浓度比DOECs高约10倍。在高浓度（10%）与低浓度（0.1%）胎牛血清刺激下的HaCaT细胞中，EGF转录本表达分别降低约50%，高浓度和低浓度胎牛血清分别代表生长刺激和生长受限条件，这意味着生长刺激对HaCaT细胞中的EGF基因活性产生负反馈。
在此，我们首次表明DOECs表达EGF，这表明这些细胞对唾液中EGF含量有贡献，因此可能在牙龈上皮修复和伤口愈合中发挥作用。
