(A) Transfecting Grade IV OA chondrocytes, we assessed effects of HA tag-PSMD11 plasmid, compared to control plasmid transfection, on proteasome activity (n=4 donors), and (B) on accumulation of K48-polyubiquitinated proteins (results representative of 4 donors). (C) PSMD11 gain of function by transfection in OA chondrocytes (n=5 different donors), validated to augment cellular HA, was assessed for effects on SOX9 levels. (D) Using ChIP assay, we separately analyzed the effect of PSMD11 gain of function on nuclear SOX9 binding to the AGC1 promoter and COL2A1 enhancer.