Journal: Bioactive Materials

Article Title: Microenvironment-educated MSC-EVs loaded injectable smart hydrogel for targeting senescent nucleus pulposus cells and inhibiting ferroptosis against intervertebral disc degeneration

doi: 10.1016/j.bioactmat.2026.02.030

Figure Lengend Snippet: Senescent Microenvironment-Educated Mesenchymal Stem Cells Release High-Affinity Senescent NPC Domesticated Extracellular Vesicles. (A) Schematic diagram of the experimental setup for educating MSCs with SASP-CM to generate D-EVs versus N-EVs. (B) Confocal microscopy images showing different EVs internalization by senescent NPCs after 12 h in vitro. (C) Flow cytometry and quantification analysis of different EVs uptake by senescent NPCs. (D) In vivo validation of the senescent niche. Representative fluorescence images following injection of senescence-tracer (Red). (E) In vivo PKH26-labeled D-EVs tracking. (F) Representative SA-β-Gal images and quantification of MSCs treated with SASP-CM or not. (G) Gene Ontology (GO) analysis confirming enrichment of external encapsulating structure organization and cytokine production in Biological Process (BP) categories. (H) Heatmap indicating gene expression associated with EVs biogenesis within D-MSCs and N-MSCs. (I) Heatmap indicating gene expression associated with cytokine production within D-MSCs and N-MSCs. (J and L) Gene Ontology (GO) analysis confirming enrichment of terms related to vesicle organization and transport in the Cellular Component (CC) categories. (K) Western blot analysis confirmed core senescence markers p16 and p21 and DNA damage marker γ-H2AX in N-MSC and D-MSC. (M) Western blot analysis confirmed the expression of CD9, CD63, TSG101, Calnexin, and GM130 in MSC-EVs, N-EVs, or D-EVs. (N) TEM images showing the morphology and size of MSC-derived EVs, N-EVs, and D-EVs. (O) NTA shows size distribution in MSC-EVs, N-EVs, or D-EVs. The data were presented as mean ± SD. n = 3, ns, not significant; ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001.

Article Snippet: After blocked with 5% non-fat milk for 2 h at room temperature, the membranes were incubated with primary antibodies against GAPDH (1:5000, 104941-AP, Proteintech), TSG101 (1:1000, DF8427, Affinity), CD9 (1:1000, AF5139, Affinity), CD63 (1:2000, 25682-1-AP, Proteintech), Calnexin (1:5000, 10427-2-AP, Proteintech), GM130 (1:20000, 11308-1-AP, Proteintech), CXCR3 (1:5000, 26756-1-AP, Proteintech), CXCL10 (1:2000, 10937-1-AP, Proteintech), MMP3 (1:2000, 17873-1-AP, Proteintech), ADAMTS5 (DF13268, Affinity), P16 (AF5484, Affinity), P21 (10355-1-AP, Proteintech), GPX4 (1:1000, 381958, Zen-bio), SLC7A11 (1:1000, 26864-1-AP, Proteintech), ACSL4 (1:5000, 22401-1-AP, Proteintech) and Tubulin (1:10000, T40103 , Abmart) overnight at 4 °C.

Techniques: Confocal Microscopy, In Vitro, Flow Cytometry, In Vivo, Biomarker Discovery, Fluorescence, Injection, Labeling, Gene Expression, Western Blot, Marker, Expressing, Derivative Assay