Fig. 5

Metformin delays astrocytes senescence by blocking astrocytic Mfn2-cGAS. A–D Astrocytes were transfected with vector or Mfn2 plasmid for 48 h and then treated with metformin (0.2 mM) and MPP⁺. qPCR measurement of the levels of IL-1α (A), IL-1β (B), IL-6 (C), and MMP3 (D) in astrocytes (Four independent experiments). E, F Representative images of SA-β-gal staining and quantification of the percentage of SA-β-gal⁺ astrocytes over total astrocytes in astrocytes (Three independent experiments). DAPI stains nucleus (blue). G–J Representative immunoblots (G) and quantification of relative expression of p16 (H), cGAS (I) and p-STING (J) in astrocytes (Three independent experiments). K Heatmap of relative mRNA levels of SASP as indicated in SNpc (n = 3 animals for each group). L–Q qPCR measurement of the levels of IL-1α (L), IL-1β (M), IL-6 (N), MMP3 (O), MMP9 (P), and p16^Ink4a (Q) in the SNpc (n = 6 animals for each group). R Representative double-immunostaining for lamin B1 and astrocytic marker GFAP in the SNpc. DAPI stains nucleus (blue). S Quantification of lamin B1 immunofluorescence intensity in GFAP⁺ astrocytes in the SNpc (n = 6 animals for each group). The data shown are the mean ± SEM. Two-way ANOVA with Tukey’s post-hoc tests were used. **p < 0.01, ***p < 0.001, NS: no significant