Demonstration of osteocytic perilacunar/canalicular remodeling in mice during lactation

作者：Hai Qing, Laleh Ardeshirpour, Paola Divieti Pajevic, Vladimir Dusevich, Katharina Jähn, Shigeaki Kato, John J. Wysolmerski, Lynda Faye Bonewald · 发表于：Journal of Bone and Mineral Research · 年份：2012 · DOI：10.1002/jbmr.1567 · 被引用次数：499 · 研究领域：Connective tissue disorders research、Fibroblast Growth Factor Research、Growth Hormone and Insulin-like Growth Factors

Osteoclasts are thought to be solely responsible for the removal of bone matrix. However, we show here that osteocytes can also remove bone matrix by reversibly remodeling their perilacunar/canalicular matrix during the reproductive cycle. In contrast, no osteocytic remodeling was observed with experimental unloading despite similar degrees of bone loss. Gene array analysis of osteocytes from lactating animals revealed an elevation of genes known to be utilized by osteoclasts to remove bone, including tartrate-resistant acid phosphatase (TRAP) and cathepsin K, that returned to virgin levels upon weaning. Infusion of parathyroid hormone-related peptide (PTHrP), known to be elevated during lactation, induced TRAP activity and cathepsin K expression in osteocytes concurrent with osteocytic remodeling. Conversely, animals lacking the parathyroid hormone type 1 receptor (PTHR1) in osteocytes failed to express TRAP or cathepsin K or to remodel their osteocyte perilacunar matrix during lactation. These studies show that osteocytes remove mineralized matrix through molecular mechanisms similar to those utilized by osteoclasts.