Synovial mesenchymal stem cell-derived exosomes delivering GRPEL1 activate PINK1-mediated mitophagy to promote cartilage repair in arthritis

Figure 5 Synovial mesenchymal stem cell-derived exosomes delivery of GrpE-like 1 mitigates interleukin-1 beta-induced changes in CHON-001 cells. A: Immunofluorescence tracking of Dil-labeled exosomes demonstrates cellular internalization and distribution across different experimental conditions, revealing exosomal uptake dynamics; B: Quantitative real-time polymerase chain reaction analysis of GrpE-like 1 (GRPEL1) mRNA expression levels in CHON-001 cells, providing molecular insights into genetic cargo transfer and expression; C: Western blot examination confirms GRPEL1 protein expression, complementing transcriptional analysis and validating exosomal cargo delivery; D: CCK-8 assay evaluates cellular viability, assessing the protective potential of GRPEL1-delivered exosomes against interleukin-1 beta-induced cellular stress; E: Transwell migration assay investigates cellular migratory capabilities, elucidating potential functional modifications induced by exosomal GRPEL1; F: Western blot analysis of cartilage-associated proteins (collagen II, aggrecan, a disintegrin and metalloproteinase with thrombospondin motifs 5, matrix metalloproteinase-13) reveals molecular changes in chondrocyte phenotype and matrix metabolism. Scale bar: 50 μm. ^bP < 0.01 vs control; ^dP < 0.01 vs IL-1β; ^fP < 0.01 vs IL-1β + Exo-oeNC; ^hP < 0.01 vs IL-1β + Exo-shNC. IL-1β: Interleukin-1 beta; Exo: Exosome; DAPI: 4’-6-diamidino-2-phenylindole; GRPEL1: GrpE-like 1; OD: Optical density; ADAMTS5: A disintegrin and metalloproteinase with thrombospondin motifs 5; MMP-13: Matrix metalloproteinase-13.