Journal: Bioactive Materials

Article Title: Metformin alleviates aging-associated periodontitis via NRF2-mediated restoration of the IRE1α dependent unfolded protein response

doi: 10.1016/j.bioactmat.2026.03.060

Figure Lengend Snippet: NRF2 restores UPR function through upregulating IRE1α. (A, B) PDLSCs were transduced with an adenovirus vector or loaded with NRF2 (Adv- GFP / NRF2 ), followed by administrated with LPS and/or D-gal. Western blot for UPR markers (A) in PDLSCs. IF staining for IRE1α in PDLSCs (B). (C, D) PDLSCs were administered with NRF2 inhibitor (ML385), followed by treatment with LPS and/or D-gal. Protein levels of UPR markers (C). IF staining for IRE1α (D). (E) IF staining of IRE1α in WT and Nrf2 −/− mice, settled with the periodontitis model and D-gal induced aged mouse model. (F) Prediction of NRF2's binding motifs on the promoters of UPR markers in the JASPAR database ( https://jaspar.elixir.no/ ). (G) Prediction of the relationship between NRF2 and IRE1α mRNA expression in the GEPIA database ( http://gepia.cancer-pku.cn/ ). (H) CUT-RUN-qPCR assay and agarose gel electrophoresis for the binding of NRF2 to IRE1α promoter in PDLSCs. Data are presented as means ± SEM (n = 3 per subgroup). ∗P < 0.05.

Article Snippet: The primary antibodies used were IRE1α (A17940, ABclonal) and NRF2 (ab62352, Abcam).

Techniques: Transduction, Plasmid Preparation, Western Blot, Staining, Binding Assay, Expressing, Agarose Gel Electrophoresis

Journal: Bioactive Materials

Article Title: Metformin alleviates aging-associated periodontitis via NRF2-mediated restoration of the IRE1α dependent unfolded protein response

doi: 10.1016/j.bioactmat.2026.03.060

Figure Lengend Snippet: Metformin suppresses SASP and upregulates NRF2 and UPR markers expression in senescent PDLSCs. (A) P16 and P21 expression in PDLSCs treated with metformin combined with LPS and D-gal. (B) SA-β-gal staining of PDLSCs. (C) mRNA expression level in PDLSCs. (D) Western blot for NRF2 and UPR markers in PDLSCs treated with metformin combined with LPS and D-gal. (E, F) IF staining for IRE1α (E) and NRF2 (F) in PDLSCs. (G, H) ALP (G) and ARS (H) staining of PDLSCs followed by osteogenic induction for 7 and 21 days, respectively. (I) Protein expression levels of osteogenic markers in PDLSCs were followed by 7 days of osteogenic induction. Data are presented as means ± SEM (n = 3 per subgroup). ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001.

Article Snippet: The primary antibodies used were IRE1α (A17940, ABclonal) and NRF2 (ab62352, Abcam).

Techniques: Expressing, Staining, Western Blot

Journal: Bioactive Materials

Article Title: Metformin alleviates aging-associated periodontitis via NRF2-mediated restoration of the IRE1α dependent unfolded protein response

doi: 10.1016/j.bioactmat.2026.03.060

Figure Lengend Snippet: In vivo therapeutic effect of the TAM-GM@Met on mice with an aging-associated periodontitis model. (A) Schematic illustration of the therapeutic process on the D-gal induced aging mice periodontitis model. (B) Micro-CT reconstructions and buccal-palatal sectional views of maxillary molars and evaluation of the distance from the CEJ to the ABC. (C, D) Mice periodontal tissue sections prepared for H&E staining (C) and Masson's trichrome staining (D). (E) Schematic of TAM-GM@Met preparation. TAM hydrogel incorporates galactose-coated MPDA nanoparticles (GM) to target senescent cells for metformin delivery. Metformin activates NRF2, leading to transcriptional upregulation of IRE1α, restoration of the UPR, and suppression of SASP in PDLSCs. ns, not significant; TAM, tannic acid and Ag-MOFs based hydrogel; MPDA, mesoporous polydopamine; UPR, unfolded protein response. Data are presented as means ± SEM (n = 5 per subgroup). ∗∗∗P < 0.001.

Article Snippet: The primary antibodies used were IRE1α (A17940, ABclonal) and NRF2 (ab62352, Abcam).

Techniques: In Vivo, Micro-CT, Staining