High glucose upregulates BMAL1 in chondrocytes from macroscopically normal and osteoarthritic human cartilage but this only results in increased collagen synthesis in chondrocytes from macroscopically normal cartilage regions

These data demonstrate a novel mechanism by which high glucose-mediated upregulation of BMAL1 promotes collagen synthesis in chondrocytes. Although high glucose leads to similar upregulation of BMAL1 and P4HA2 in both MN and OA chondrocytes, overall lower <i>COL2A1</i> RNAin OA chondrocytes likely limits their ability to upregulate secreted procollagen II levels. Hence, MN but not OA chondrocytes show increased collagen II production in high glucose.