The prevalence of periodontitis increases with physiological aging. However, whether bacteria associated with periodontal diseases foster aging and the mechanisms by which they may do so are unknown. Herein, we hypothesize that Fusobacterium nucleatum, a microorganism associated with periodontitis and several other age-related disorders, triggers senescence, a chief hallmark of aging responsible to reduce tissue repair capacity. Our study analyzed the senescence response of gingival epithelial cells and their reparative capacity upon long-term exposure to F. nucleatum. Specifically, we assessed (a) cell cycle arrest by analyzing the cyclin-dependent kinase inhibitors p16^INK4a and p14^ARF and their downstream cascade (pRb, p53, and p21) at both gene and protein levels, (b) lysosomal mediated dysfunction by using assays targeting the expression and activity of the senescence-associated β-galactosidase (SA-β-Gal) enzyme, and (c) nuclear envelope breakdown by assessing the expression of Lamin-B1. The consequences of the senescence phenotype mediated by F. nucleatum were further assessed using wound healing assays. Our results revealed that prolonged exposure to F. nucleatum promotes an aging-like phenotype as evidenced by the increased expression of pro-senescence markers (p16^INK4a, p21, and pRb) and SA-β-Gal activity and reduced expression of the counter-balancing cascade (p14^ARF and p53) and Lamin-B1. Furthermore, we also noted impaired wound healing capacity of gingival epithelial cells upon prolong bacterial exposure, which was consistent with the senescence-induced phenotype. Together, our findings provide a proof-of-concept evidence that F. nucleatum triggers a pro-senescence response in gingival epithelial cells. This might affect periodontal tissue homeostasis by reducing its repair capacity and, consequently, increasing susceptibility to periodontitis during aging.

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具核梭杆菌触发牙龈上皮细胞衰老表型

牙周炎的患病率随着生理老化而增加。然而，与牙周病相关的细菌是否会促进衰老及其机制尚不清楚。在此，我们假设具核梭杆菌（一种与牙周炎和其他几种与年龄相关的疾病相关的微生物）会引发衰老，这是衰老的主要标志，会降低组织修复能力。我们的研究分析了长期暴露于具核梭杆菌后牙龈上皮细胞的衰老反应及其修复能力。具体来说，我们通过在基因和蛋白质水平上分析细胞周期蛋白依赖性激酶抑制剂 p16 ^INK4a和 p14 ^ARF及其下游级联（pRb、p53 和 p21）来评估（a）细胞周期停滞，（b）通过使用针对衰老相关 β-半乳糖苷酶 (SA-β-Gal) 酶的表达和活性的测定，以及 (c) 通过评估 Lamin-B1 的表达来破坏核膜。使用伤口愈合测定进一步评估具核梭杆菌介导的衰老表型的后果。我们的结果表明，长期暴露于具核梭菌会促进衰老样表型，这一点可以通过促衰老标记物（p16 ^INK4a、p21 和 pRb）和 SA-β-Gal 活性的表达增加以及反衰老标记物的表达减少来证明。平衡级联（p14 ^ARF和 p53）和 Lamin-B1。此外，我们还注意到长期接触细菌后牙龈上皮细胞的伤口愈合能力受损，这与衰老诱导的表型一致。总之，我们的研究结果提供了概念验证证据，表明具核梭菌触发牙龈上皮细胞的促衰老反应。这可能会降低牙周组织的修复能力，从而影响牙周组织的稳态，从而增加衰老过程中患牙周炎的可能性。