LCN2 and obesity due to melanocortin 4 receptor deficiency: Accordingly, because cartilage and subchondral bone are thought to act as a functional unit6, and considering that the obesity-related adipokine LCN2, an articular catabolic adipokine, is highly induced in osteoblasts under an unloading stimulus17, 24, we decided to investigate the role of LCN2 in osteoblast and chondrocyte metabolism by mimicking the OA osteochondral junction environment.