Human umbilical cord mesenchymal stem cell-derived exosomal miR-199a-3p inhibits the MAPK4/NF-κB signaling pathway to relieve osteoarthritis

Figure 4 MiR-199a-3p inhibits the activation of the nuclear factor-kappaB signaling pathway by targeting mitogen-activated protein kinase 4. A: The level of mitogen-activated protein kinase 4 (MAPK4) mRNA in CHON-001 cells was measured via quantitative real-time polymerase chain reaction; B: Western blot analysis was used to evaluate MAPK4 protein expression in CHON-001 cells; C: StarBase (http://starbase.sysu.edu.cn/) was used to predict the specific binding sites of miR-199a-3p and MAPK4; D: Dual-luciferase reporter assays validated the interaction between miR-199a-3p and MAPK4; E: The interaction of miR-199a-3p with MAPK4 was confirmed by RNA pull-down assays; F: Quantitative real-time polymerase chain reaction was used to assess the miR-199a-3p transfection efficiency in CHON-001 cells; G: The expression levels of MAPK4 mRNA in CHON-001 cells were evaluated via quantitative real-time polymerase chain reaction; H: Western blot analysis was conducted to evaluate the expression levels of MAPK4 and p-nuclear factor-kappaB p65 in CHON-001 cells; I: Western blot analysis was used to assess the effectiveness of MAPK4 transfection in CHON-001 cells; J: Western blot analysis was used to examine the expression levels of p-nuclear factor-kappaB p65 in CHON-001 cells. ^bP < 0.01, ^cP < 0.001. MAPK4: Mitogen-activated protein kinase 4; IL: Interleukin; Exos: Exosomes; NC: Normal control; NC mimic: Negative control mimic; NC inhibitor: Negative control inhibitor; OE-NC: Overexpression negative control; OE-MAPK4: Overexpression mitogen-activated protein kinase 4; NF-κB: Nuclear factor-kappaB.