(A and B) Human OA chondrocytes were transfected with adenovirus (Ad-KLF4 or Ad-EGFP for (A), and Ad-KLF2 or Ad-EGFP for (B)), and RNA was collected 48 hours after transfection (n=9 donors). (C and D) Human meniscal cells were transfected with adenovirus (Ad-KLF4 or Ad-EGFP for (C), and Ad-KLF2 or Ad-EGFP for (D)), and RNA was collected 48 hours after transfection (n=4 donors). (E and F) Human bone marrow-derived mesenchymal stem cells (BMSCs) were transfected with adenovirus (Ad-KLF4 or Ad-EGFP for (E), and Ad-KLF2 or Ad-EGFP for (F)), and were cultured in pellets. RNA was collected 2 weeks after pellet culture (n=3 donors). mRNA levels are expressed as means±SE, relative to Ad-EGFP. *P<0.05, **P<0.01, paired t-test.