| 1 | RhoA/Rock activation represents a new mechanism for inactivating Wnt/β-catenin signaling in the aging-associated bone loss显示文摘The Wnt/β-catenin signaling pathway appears to be particularly important for bone homeostasis,whereas nuclear accumulation ofβ-catenin requires the activation of Rac1,a member of the Rho small GTPase family.The aim of the present study was to investigate the role of RhoA/Rho kinase(Rock)-mediated Wnt/β-catenin signaling in the regulation of aging-associated bone loss.We find that Lrp5/6-dependent and Lrp5/6-independent RhoA/Rock activation by Wnt3a activates Jak1/2 to directly phosphorylate Gsk3βat Tyr216,resulting in Gsk3βactivation and subsequentβ-catenin destabilization.In line with these molecular events,RhoA loss-or gain-of-function in mouse embryonic limb bud ectoderms interacts genetically with Dkk1 gain-of-function to rescue the severe limb truncation phenotypes or to phenocopy the deletion ofβ-catenin,respectively.Likewise,RhoA loss-of-function in pre-osteoblasts robustly increases bone formation while gain-of-function decreases it.Importantly,high RhoA/Rock activity closely correlates with Jak and Gsk3βactivities but inversely correlates withβ-catenin signaling activity in bone marrow mesenchymal stromal cells from elderly male humans and mice,whereas systemic inhibition of Rock therefore activates theβ-catenin signaling to antagonize aging-associated bone loss.Taken together,these results identify RhoA/Rock-dependent Gsk3βactivation and subsequentβ-catenin destabilization as a hitherto uncharacterized mechanism controlling limb outgrowth and bone homeostasis. | Wei Shi Chengyun Xu Ying Gong Jirong Wang Qianlei Ren Ziyi Yan Liu Mei Chao Tang Xing Ji Xinhua Hu Meiyu Qv Musaddique Hussain Ling-Hui Zeng Ximei Wu | 2021 | Cell Regeneration2021，10，1： | 0 |
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