High glucose disrupts autophagy lysosomal pathway in gingival epithelial cells via ATP6V0C

Hyperglycemic micro-environment induced by diabetes could regulate the response of periodontal tissues to pathogenic microorganisms in which disruption of autophagy lysosomal pathway (ALP) may participate. This study aimed to explore the mechanisms underlying how high glucose (HG) regulates ALP in gingival epithelial cells (GECs).

Human gingival tissues in healthy group (C), periodontitis group (P), diabetes group (DM), and diabetes + periodontitis group (DP) were collected and were applied to observe the fusion of autophagy and lysosome. Diabetic mouse model with periodontitis was established and RNA-seq was applied to investigate the expression of ALP-associated genes in gingival epithelium. To explore the key role of ATPase transmembrane v0 domain, subunit c (ATP6V0C) in the disruption of ALP by HG, human gingival epithelial cells (HGECs) were cultured in 5.5 mM/25 mM glucose medium for 48 hours and followed by Porphyromonas gingivalis stimulation for 0, 6, and 12 hours. HBLV-h-ATP6V0C was transfected in HGECs that were stimulated by 25 mM HG condition.

Immunofluorescence double staining exhibited the disruption of ALP in human gingival epithelium in diabetes groups and HGECs under 25 mM glucose condition, accompanied with significantly downregulated lysosomal acidity. RNA-seq of mouse gingival epithelium screened out Atp6v0c. Compared with HGECs in normal culture medium, ATP6V0C expression and LC3-II/I expression ratio were significantly downregulated, with an upregulated expression of P62, IL-1β in HGECs under HG condition. Over-expression of ATP6V0C rescued HG-induced disruption of ALP in HBLV-h-ATP6V0C transfected HGECs, with significantly upregulation of LC3-II/I and downregulation of P62, IL-1β.

ATP6V0C mediates HG-induced ALP disruption in HGECs, eventually exacerbates periodontal inflammation.