... 2Research articlePeroxisome proliferator-activated receptor γ1 expression is diminished in human osteoarthritic cartilage and is downregulated by interleukin-1β in articular chondrocytesHassan Afif1, ... proliferator-acti-vated receptor γ inhibits interleukin-1β- induced membrane-associated prostaglandin E2 synthase-1 expression in human synovial fibroblasts by interfering with Egr-1. J Biol Chem2004, ... expression of PPARγ in OA cartilage may, at least in part, be involved in increased expression of inflammatory and catabolic genes,promoting articular inflammation and cartilage degradation. In addition,...