RT Journal Article ID 03210611080ec17a A1 Boyce, Brendan A1 Yao, Zhenqiang A1 Xing, Lianping T1 Osteoclasts Have Multiple Roles in Bone in Addition to Bone Resorption JF Critical Reviews™ in Eukaryotic Gene Expression JO CRE YR 2009 FD 2009-06-26 VO 19 IS 3 SP 171 OP 180 K1 osteoclast K1 cytokine K1 osteoblast K1 bone resorption K1 inflammatory arthritis AB Osteoclasts are the cells that degrade bone to initiate normal bone remodeling and mediate bone loss in pathologic conditions by increasing their resorptive activity. They are derived from precursors in the myeloid/ monocyte lineage that circulate in the blood after their formation in the bone marrow. These osteoclast precursors (OCPs) are attracted to sites on bone surfaces destined for resorption and fuse with one another to form the multinucleated cells that resorb calcified matrixes under the influence of osteoblastic cells in bone marrow. Recent studies have identified functions for OCPs and osteoclasts in and around bone other than bone resorption. For example, they regulate the differentiation of osteoblast precursors and the movement of hematopoietic stem cells from the bone marrow to the bloodstream; they participate in immune responses, and secrete cytokines that can affect their own functions and those of other cells in inflammatory and neoplastic processes affecting bone. Here, we review these findings, which define new roles for osteoclasts and OCPs in the growing field of osteoimmunology and in common pathologic conditions in which bone resorption is increased. PB Begell House LK https://www.dl.begellhouse.com/journals/6dbf508d3b17c437,12b6e91c2627fc7a,03210611080ec17a.html