MiR-21 modulates P.g-LPS induced apoptosis and inflammatory response in HUVECs via NF-κB/iNOS/NO pathway by targeting...

Porphyromonas gingivalis lipopolysaccharide (P.g-LPS), a key virulence factor in periodontitis, contributes to systemic vascular diseases, notably atherosclerosis. MicroRNA-21 (miR-21), a critical post-transcriptional regulator, influences inflammation and vascular pathology, but its role in endothelial responses to P.g-LPS remains unclear.

Gingival biopsies from eight patients with periodontitis and eight healthy controls were analyzed using immunofluorescence co-labeling for Cluster of Differentiation 31 (CD31) with TUNEL or Interleukin-6 (IL-6) to assess endothelial apoptosis and inflammation. MiR-21 levels were quantified using quantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR). Human umbilical vein endothelial cells (HUVECs) were treated with P.g-LPS and transfected with miR-21 mimics or inhibitors. Apoptosis, proliferation, and migration were evaluated by flow cytometry, Cell Counting Kit-8 (CCK-8) assay, and wound healing analysis, respectively. Western blotting and Enzyme-Linked Immunosorbent Assay(ELISA) measured inflammatory and apoptotic markers. Luciferase reporter assays confirmed that PDCD4 was a direct target of miR-21, and the effects of Programmed Cell Death 4(PDCD4) knockdown on Nuclear Factor kappa B (NF-κB)/Inducible Nitric Oxide Synthase (iNOS)/Nitric Oxide (NO) signaling were examined.

Endothelial cells from patients with periodontitis exhibited increased apoptosis and inflammation. P.g-LPS significantly reduced miR-21 expression in HUVECs. MiR-21 inhibition exacerbated apoptosis and inflammatory mediator expression, while suppressing proliferation and migration.MiR-21 overexpression mitigated these effects. PDCD4 was validated as a direct miR-21 target. Suppression of miR-21 enhanced NF-κB/iNOS/NO activation, and PDCD4 knockdown attenuated this pathway, indicating a regulatory mechanism.

MiR-21 acts as a protective regulator against P.g-LPS-induced endothelial injury by targeting PDCD4 and modulating the NF-κB/iNOS/NO pathway, thereby reducing inflammation and apoptosis. These findings indicate that miR-21 is a potential therapeutic target for vascular complications associated with chronic inflammatory diseases like periodontitis.