Fig. 1: Characterization of CircFNDC3B in human control and OA tissues.

a Heat map based on OA tissue and control tissue. b The relative expression of CircFNDC3B in human medial tibial plateau (MTP) and lateral tibial plateau (LTP) was detected by RT-qPCR. (n = 10). c The expression of CircFNDC3B in human MTP and LTP was revealed by RNA FISH. Scale bars are 50 µm and 100 µm. d Safranin-O/fast green staining of the cartilage from MTP and LTP of human sample. Scale bars are 100 µm and 200 µm. e HCs were treated with IL-1β (10 ng/mL) for 12 h, 24 h, and 48 h, the relative CircFNDC3B expression were detected by RT-qPCR. (n = 3) f The presence of CircFNDC3B was validated by Sanger sequencing. g The diagram demonstrated how FNDC3B gene formed FNDC3B mRNA (Left arrow) and circFNDC3B (right arrow). CircFNDC3B was validated by divergent primers. h RT-qPCR showed that CircFNDC3B could resist RNase R. (n = 3). i RNA FISH demonstrated the cellular localization of CircFNDC3B. Scale bar, 50 μm. j The expression of CircFNDC3B and FNDC3B mRNA in nucleus or cytoplasm of HCs treated with or without RNase R was detected by RT-PCR. (n = 3). Mean ± SEM; **p < 0.01; ***p < 0.001 by Student’s t test.