Epidermal growth factor receptor (EGRF)-signaling is a key mediator of hormone-induced leukocyte infiltration in the pubertal female mammary gland.
Aupperlee MD, Zhao Y, Tan YS, Leipprandt JR, Bennett JM, Haslam SZ, Schwartz RC.
Michigan State University, Lansing, MI.
It is well known that certain white blood cells play important roles in normal mouse mammary gland development at puberty. While it is also known that estrogen and progesterone are key players in mammary gland development, the roles these hormones might play in regulating the actions of white blood cells in that process has not been well studied. We now have shown that estrogen and progesterone, respectively, induce unique, but overlapping, sets of genes that are typically involved in inflammation and blood vessel development in the pubertal mouse mammary gland, as well as induce the entry of white blood cells into the mammary gland. Importantly, epidermal growth factor (EGFR)-signaling, which is likely carried out by a protein called amphiregulin, is responsible for recruitment of white blood cells to the mammary gland by estrogen and progesterone. Another protein called RANKL also contributes to the effects of progesterone. Amphiregulin by itself can induce white blood cell recruitment at levels similar to those observed with estrogen and progesterone. Our new finding extends a previously described role for amphiregulin in regulating growth of ducts in the pubertal mammary gland.