Bone anabolic effects of osteoclast-produced phospho-Wnt5a

项目摘要 仍然需要找到治疗骨质疏松症的新的有效和成本效益高的合成代谢骨药物。 条件、骨骼脆性和修复。本申请的目标是建立WNT5a的磷酸化形式 破骨细胞产生的破骨因子，能够促进体内的骨形成。这是随附的 将拟磷化Wnt5a多肽作为促进成骨的合成药物的翻译承诺 未来。拟议的工作的前提是我们令人信服的初步证据，即有条件删除 来自破骨细胞(OCL)的WNT5A导致骨量减少，并伴随着骨减少 体内形成率。我们进一步在破骨细胞中发现了Wnt5a特异的丝氨酸磷酸化。这 磷酸化WNT5a或其模拟突变蛋白促进成骨。因此，我们假设一个 Wnt5a的磷酸化形式由OCL产生，而不是OBS，作为促进合成代谢的碎裂因子 骨形成。为了验证这一假说，我们将：首先建立OCL对OB功能的体内控制- 产生了Wnt5a，并确定了Wnt5a在OCL前体中过度表达的骨骼后果(第一 目标)。然后我们将揭示翻译后修饰形式所通过的细胞和分子机制 OCL产生的WNT5a在体外和体内均可调控OB功能。最后，我们将产生诱导多能性 通过基因组编辑表达磷酸化缺陷和模拟WNT5a突变体的干细胞促进骨生长 在小鼠临界大小的颅骨缺损处形成(第二个目的)。

Project Summary There is still a need to identify new efficacious and cost effective anabolic bone drugs to treat osteopenic conditions, bone fragility and repair. The goal of this application is to establish a phosphorylated form of Wnt5a produced by osteoclasts as a clastokine, capable of enhancing bone formation in vivo. This comes with the translational promise to deliver phosphomimetic Wnt5a peptide as an anabolic drug to promote osteogenesis in the future. The proposed work is premised on our compelling preliminary evidence that conditional deletion of Wnt5a from osteoclasts (OCLs) resulted in decreased bone mass, which was concomitant with decreased bone formation rate in vivo. We further discovered a specific Ser phosphorylation of Wnt5a in osteoclastic cells. This phospho-Wnt5a or its mimetic mutant proteins promoted osteogenesis. We therefore hypothesize that a phosphorylated form of Wnt5a, produced by OCL but not OBs, serve as a clastokine to promote anabolic bone formation. To verify this hypothesis, we will: first establish the in vivo control of OB function by OCL- produced Wnt5a and determine the skeletal consequences of Wnt5a over-expression in OCL-precursors (First Aim). We will then reveal the cellular and molecular mechanisms via which a post-translationally modified form of Wnt5a produced by OCL control OB function in vitro and in vivo. Finally, we will generate induced pluripotent stem cells expressing phospho-defective and -mimetic Wnt5a mutants via genome editing to promote bone formation in a murine critical sized calvarial defect (Second Aim).