Bone remodeling targets

Bone is continuously broken down by osteoclasts and formed by osteoblasts. Studying this cycle has revealed a number of targets for use as potential treatments for bone diseases like osteoporosis. One of the more heavily explored steps in the process is the differentiation of hematopoietic cells to osteoclasts [1]. There are already compounds in the clinic and on the market attacking targets in this step, including selective estrogen receptor modulators (SERMs), selective androgen receptor modulators (SARMs), and blockers of receptor activator of nuclear factor-kappa B ligand (RANKL). Other targets being investigated here include osteoprotegrin, NFATc1 and other proteins in the CaMK-CREB pathway and TNF-associated factors (TRAFs). Once hematopoetic cells become mononuclear osteoclasts, they fuse together forming multinucleated osteoclasts, a process that has recently been found to involve Atp6v02 [2]. Multinucleated osteoclasts then go on to break down bone mineral and matrix, which involves various proteins such as calcitonin receptor, cathepsin K and TRAFs [3]. ...