The interconnected role of chemokines and estrogen in bone metabolism.

Over the past few decades, researchers have paid considerable attention to the relationship between estrogen and bone metabolism. Nevertheless, few studies have examined the potential role of chemokines in estrogen regulation of bone metabolism. Chemokines are members of a superfamily of low-molecular-weight chemoattractant cytokines. Various chemokines and their corresponding transmembrane G protein-coupled receptors play distinct roles in the functional regulation and homeostasis of the immune and skeletal systems. This review summarizes the evidence that chemokines and estrogen display cooperative behavior in the skeletal system, with a focus on the mechanisms by which estrogen regulates the chemotactic factors that affect bone metabolism. Chemokines appear to represent a novel area for further examination in order to develop new therapeutics to treat disorders of bone metabolism.