Fig. 3.

Exosomal circ_0001236 validation and expression in OA and healthy cartilage chondrocytes. a The presence of exosomal circ_0001236 was validated in primary human chondrocytes by RT-PCR. Divergent primers amplified circ_0001236 from cDNA, but not from genomic DNA. GAPDH was used as a negative control. b Schematic illustration showing the circularization of ZC3H78 exons 12 and 13 to form circZC3H78. The presence of circ_0001236 was validated by RT-PCR, followed by Sanger sequencing. c Northern blot analysis for the detection of circZC3H78 and ZC3H78 expression in chondrocytes treated with or without RNase R. d–f RNA FISH revealed the predominant localization of circ_0001236 in the cytoplasm. circ_0001236 probes were labeled with Cy-3. The nuclei were stained with DAPI (scale bar, 20 μm). g circ_0001236 expression was higher in healthy cartilage than in OA cartilage tissues (scale bar, 50 μm). The experiment was repeated independently three times, and representative results are shown