Metformin alleviates junctional epithelium senescence via the AMPK/SIRT1/autophagy pathway in periodontitis induced by hyperglycemia

Xiaoyuan Ye; Yumin Wang; Yanying Tian; Ruonan Bi; Mingyue Li; Chunyan Yang; Li Zhang; Yuguang Gao

doi:10.1016/j.heliyon.2024.e27478

Metformin alleviates junctional epithelium senescence via the AMPK/SIRT1/autophagy pathway in periodontitis induced by hyperglycemia

Heliyon. 2024 Mar 8;10(6):e27478. doi: 10.1016/j.heliyon.2024.e27478. eCollection 2024 Mar 30.

Authors

Xiaoyuan Ye¹, Yumin Wang², Yanying Tian¹, Ruonan Bi¹, Mingyue Li¹, Chunyan Yang², Li Zhang², Yuguang Gao¹

Affiliations

¹ Department of Pediatrics and Preventive Dentistry, Binzhou Medical University Hospital, Binzhou, 256699, Shandong, China.
² Institute of Stomatology, Binzhou Medical University, Yantai, 264003, Shandong, China.

Abstract

The junctional epithelium (JE) serves a crucial protective role in the periodontium. High glucose-related aging results in accelerated barrier dysfunction of the gingival epithelium, which may be associated with diabetic periodontitis. Metformin, an oral hypoglycemic therapeutic, has been proposed as a anti-aging agent. This study aimed to clarify the effect of metformin on diabetic periodontitis and explore its mechanism in ameliorating senescence of JE during hyperglycemia. The db/db mice was used as a diabetic model mice and alterations in the periodontium were observed by hematoxylin-eosin staining and immunohistochemistry. An ameloblast-like cell line (ALC) was cultured with high glucose to induce senescence. Cellular senescence and oxidative stress were evaluated by SA-β-gal staining and Intracellular reactive oxygen species (ROS) levels. Senescence biomarkers, P21 and P53, and autophagy markers, LC3-II/LC3-I, were measured by western blotting and quantitative real-time PCR. To construct a stable SIRT1 (Sirtuin 1) overexpression cell line, we transfected ALCs with lentiviral vectors overexpressing the mouse SIRT1 gene. Cellular senescence was increased in the JE of db/db mice and the periodontium was destroyed, which could be alleviated by metformin. Moreover, oxidative stress and cellular senescence in a high glucose environment were reduced by metformin in in-vitro assays. The autophagy inhibitor 3-MA and SIRT1 inhibitor EX-527 could dampen the effects of metformin. Overexpression of SIRT1 resulted in increased autophagy and decreased oxidative stress and cellular senescence. Meanwhile, AMPK (AMP-activated protein kinase) inhibition reversed the anti-senescence effects of metformin. Overall, these results suggest that metformin alleviates periodontal damage in db/db mice and cellular senescence in ALCs under high glucose conditions via the AMPK/SIRT1/autophagy pathway.

Keywords: Hyperglycemia; Junctional epithelium; Metformin; Oxidative stress; Periodontitis; Senescence.