Journal: Autophagy
Article Title: CircAASS alleviates renal injury and fibrosis by regulating mitochondrial homeostasis in tubular epithelial cells
doi: 10.1080/15548627.2025.2581212
Figure Lengend Snippet: Cytoplasmic circAASS modulates MIR324-3p /PINK1 axis-regulated mitophagy in TECs. (A) RIP assay confirms the interaction between circAASS and AGO2. (B) qPCR analysis showing the expression of PINK1 in circAASS -overexpressing HK2 cells. (C) Western blotting showing the protein expression of PINK1, SQSTM1/p62 and LC3 in circAASS -overexpressing HK2 cells exposed to H/R treatment. (D and E) mKeima expression in HK2 cells transfected with circAASS or empty vector, with or without H/R treatment. Live-cell confocal imaging was performed (excitation 561 nm: red; excitation 488 nm: green). The 561/488 nm excitation ratio of mKeima was quantified; n = 3. (F) Integrative analysis of bioinformatics prediction to screen for circAASS -binding miRNAs, MIR324-3p and MIR345-5p are the candidate miRNAs that also target 3‘ UTR of PINK1 . (G and H) Luciferase reporter assays showing MIR324-3p mimics, but not MIR345-5p mimics, remarkably inhibited luciferase activity of PINK1 -3‘ UTR or circAASS , as compared to NC mimics. (I and J) Luciferase reporter assays showing mutant circAASS or mutant PINK1 -3’ UTR reversed the effects of MIR324-3p mimics on luciferase activity of PINK1 -3‘UTR or circAASS . (K) RIP assay showing that circAASS directly bound to MIR324-3p in HK2 cells. (L) RNA FISH showing the colocalization of circAASS and MIR324-3p in the cytoplasm of HK2 cells. (M-S) Western blot and quantification data showing the expression of mitophagy related factors in circAASS -overexpressed HK2 cells transfected with NC mimic or MIR324-3p . (T) qPCR analysis of pro-inflammatory gene expression ( TNF , IL1B , CCL2 ) in HK2 cells. PINK1 knockdown markedly exacerbated the inflammatory response induced by H/R and abolished the anti-inflammatory effect of circAASS overexpression. Data are presented as the mean ± sd. *** p < 0.001, by 2-tailed Student’s t test (A, B and K). *** p < 0.001, by 1-way ANOVA with Tukey’s multiple-comparison test (E, G, H, I, J, N, O, P, Q, R, S, and T). Scale bars: 25 μm (D) and 10 μm (l).
Article Snippet: Sections were hybridized with digoxin-labeled LNA-modified circAASS probe (Sangon Biotech, Shanghai) at 52°C for 16 h. Following washing, sections were incubated overnight at 4°C with an anti-digoxigenin monoclonal antibody (Abcam, ab419; dilution 1:200) to facilitate detection.
Techniques: Expressing, Western Blot, Transfection, Plasmid Preparation, Imaging, Binding Assay, Luciferase, Activity Assay, Mutagenesis, Gene Expression, Knockdown, Over Expression, Comparison