State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, 430079, China.
Inflammation. 2024 Dec;47(6):1918-1935. doi: 10.1007/s10753-024-02014-5. Epub 2024 Apr 17.
Periodontal disease is the pathological outcome of the overwhelming inflammation in periodontal tissue. Cellular senescence has been associated with chronic inflammation in several diseases. However, the role of cellular senescence in the pathogenesis of periodontal disease remained unclear. This study aimed to investigate the role and the mechanism of cellular senescence in periodontal disease. Using single-cell RNA sequencing, we first found the upregulated level of cellular senescence in fibroblasts and endothelial cells from inflamed gingival tissue. Subsequently, human gingival fibroblasts isolated from healthy and inflamed gingival tissues were labeled as H-GFs and I-GFs, respectively. Compared to H-GFs, I-GFs exhibited a distinct cellular senescence phenotype, including an increased proportion of senescence-associated β-galactosidase (SA-β-gal) positive cells, enlarged cell morphology, and significant upregulation of p16 expression. We further observed increased cellular reactive oxygen species (ROS) activity, mitochondrial ROS, and DNA damage of I-GFs. These phenotypes could be reversed by ROS scavenger NAC, which suggested the cause of cellular senescence in I-GFs. The migration and proliferation assay showed the decreased activity of I-GFs while the gene expression of senescence-associated secretory phenotype (SASP) factors such as IL-1β, IL-6, TGF-β, and IL-8 was all significantly increased. Finally, we found that supernatants of I-GF culture induced more neutrophil extracellular trap (NET) formation and drove macrophage polarization toward the CD86-positive M1 pro-inflammatory phenotype. Altogether, our findings implicate that, in the inflamed gingiva, human gingival fibroblasts acquire a senescent phenotype due to oxidative stress-induced DNA and mitochondrial damage, which in turn activate neutrophils and macrophages through the secretion of SASP factors.
牙周病是牙周组织炎症反应失控的病理性结果。细胞衰老与几种疾病的慢性炎症有关。然而，细胞衰老在牙周病发病机制中的作用尚不清楚。本研究旨在探讨细胞衰老在牙周病中的作用和机制。通过单细胞 RNA 测序，我们首先发现炎症性牙龈组织中的成纤维细胞和内皮细胞中细胞衰老水平上调。随后，分别将从健康和炎症性牙龈组织中分离的人牙龈成纤维细胞标记为 H-GFs 和 I-GFs。与 H-GFs 相比，I-GFs 表现出明显的细胞衰老表型，包括衰老相关β-半乳糖苷酶（SA-β-gal）阳性细胞比例增加、细胞形态增大和 p16 表达显著上调。我们进一步观察到 I-GFs 的细胞活性氧（ROS）活性、线粒体 ROS 和 DNA 损伤增加。ROS 清除剂 NAC 可逆转这些表型，提示 I-GFs 中细胞衰老的原因。迁移和增殖实验表明 I-GFs 的活性降低，而衰老相关分泌表型（SASP）因子如 IL-1β、IL-6、TGF-β和 IL-8 的基因表达均显著增加。最后，我们发现 I-GF 培养物的上清液诱导更多的中性粒细胞胞外诱捕网（NET）形成，并促使巨噬细胞向 CD86 阳性 M1 促炎表型极化。总之，我们的研究结果表明，在炎症性牙龈中，由于氧化应激诱导的 DNA 和线粒体损伤，人牙龈成纤维细胞获得衰老表型，进而通过 SASP 因子的分泌激活中性粒细胞和巨噬细胞。
