Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Department of Stomatology, Hwa Mei Hospital, University of Chinese Academy of Sciences, Ningbo, China.
J Clin Lab Anal. 2021 Jun;35(6):e23784. doi: 10.1002/jcla.23784. Epub 2021 May 2.
The pathogenesis of fibrous epulis is still quite unclear. Our recent genome-wide RNA sequencing analysis revealed that in fibrous epulis, RAS-PI3K-AKT-NF-κB pathway regulates the expression of Bcl-2 family and IAP family genes, leading to increased proliferation and the inhibition of apoptosis. The PI3K/AKT signaling pathway can promote autophagy in human gingival fibroblasts; therefore, the purpose of the present study was to identify whether autophagy is involved in the pathogenesis of fibrous epulis.
Differentially expressed genes (DEGs) between fibrous epulis lesions and normal gingival tissues were identified using the PCR array. The expression levels of eighteen autophagy-related (ATG) family genes, twelve B-cell lymphoma 2 (Bcl-2) family genes, and eleven cysteine-dependent aspartate-directed protease (caspase) family genes were validated using quantitative real-time PCR (qRT-PCR). Autophagy induction was determined by measuring microtubule-associated protein light chain 3 (LC3) conversion (LC3-I to LC3-II) by immunoblot analysis.
The PCR array identified six upregulated genes, whereas no genes were expressed at significantly lower levels. The upregulated genes were BCL2, BCL2L1, CXCR4, HSP90AA1, HSPA8, and IGF1, which all belong to the "regulation of autophagy" group but not the "autophagy machinery components" group. qRT-PCR verified that the expression levels of BCL2, BCL2L1 (also known as BCL-XL), and BCL2L2 (also known as BCL-W) were significantly increased in fibrous epulis. No LC3-I to LC3-II conversion was observed.
The present study reveals that in fibrous epulis, Bcl-2 and Bcl-xL coordinately mediate gingival cell escape from apoptosis, leading to uncontrolled proliferation. Moreover, ATG family genes are not activated, and autophagy is not involved in this process.
纤维性龈瘤的发病机制尚不清楚。我们最近的全基因组 RNA 测序分析显示，在纤维性龈瘤中，RAS-PI3K-AKT-NF-κB 通路调节 Bcl-2 家族和 IAP 家族基因的表达，导致增殖增加和凋亡抑制。PI3K/AKT 信号通路可促进人牙龈成纤维细胞的自噬；因此，本研究旨在确定自噬是否参与纤维性龈瘤的发病机制。
使用 PCR 阵列鉴定纤维性龈瘤病变与正常牙龈组织之间的差异表达基因（DEGs）。使用定量实时 PCR（qRT-PCR）验证十八个自噬相关（ATG）家族基因、十二个 B 细胞淋巴瘤 2（Bcl-2）家族基因和十一个半胱氨酸依赖性天冬氨酸定向蛋白酶（caspase）家族基因的表达水平。通过免疫印迹分析测量微管相关蛋白轻链 3（LC3）转化（LC3-I 至 LC3-II）来确定自噬诱导。
PCR 阵列鉴定出六个上调基因，而没有基因表达水平显著降低。上调的基因是 BCL2、BCL2L1、CXCR4、HSP90AA1、HSPA8 和 IGF1，它们都属于“自噬调节”组，而不属于“自噬机制成分”组。qRT-PCR 验证了纤维性龈瘤中 BCL2、BCL2L1（也称为 BCL-XL）和 BCL2L2（也称为 BCL-W）的表达水平显著增加。未观察到 LC3-I 至 LC3-II 的转化。
本研究表明，在纤维性龈瘤中，Bcl-2 和 Bcl-xL 协同介导牙龈细胞逃避凋亡，导致不受控制的增殖。此外，ATG 家族基因未被激活，自噬不参与该过程。
