Monaci Sara, Wu Mengrui, Okada Hiroyuki, Mesil Kedkanya, Keum Byeong-Rak, Monseff Rodrigues da Silva Maisa, Rosen Clifford J, Gori Francesca, Baron Roland
Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, Massachusetts, USA.
MaineHealth Institute for Research, Maine Medical Center, Scarborough, Maine, USA.
JCI Insight. 2025 Jul 22;10(16). doi: 10.1172/jci.insight.191245. eCollection 2025 Aug 22.
Parathyroid hormone (PTH) regulates serum calcium and phosphate through its actions in bone and kidney and is used to increase bone in osteoporosis treatment. In bone, PTH targets osteoblasts and osteocytes to regulate bone remodeling but also bone marrow stromal cells (BMSCs), regulating their differentiation in the osteoblast or the adipocyte lineage. PTH exerts its action through the PTH/PTH-related peptide (PTHrP) receptor, a G protein-coupled receptor (GPCR), activating adenylyl cyclase and phospholipase C (PLC). Although the effects of cAMP and PKA are well characterized, little is known about the effects of PLC activation or on the crosstalk between PTH signaling and other pathways. Here, bulk RNA-Seq of PTH-treated murine BMSC line (W-20) revealed significant changes in the Hippo pathway. In addition to increasing its transcription, PTH stabilized YAP protein, a key target of Hippo, by decreasing YAP/LArge Tumor Suppressor kinase 1 (LATS1) interaction, YAPS127 phosphorylation, and YAP ubiquitination, leading to YAP nuclear translocation and expression of YAP target genes. Similar events occurred in osteocyte cell lines. This occurred via an increase in Src kinase activity: We identified YAPY428 as a key tyrosine residue phosphorylated by Src in response to PTH. Preventing YAPY428 phosphorylation led to YAP instability, blocking both osteogenic and adipogenic differentiation of W-20 cells. These results demonstrate active crosstalk between the PTH/PTHrP and the Hippo signaling pathways and reveal that PTH signaling utilizes the PLC/Ca2+/Src tyrosine kinase signaling cascade to influence YAP stability, antagonizing Hippo signaling and favoring stromal cell differentiation. Thus, PTH signaling counteracts the effects of Hippo signaling in BMSCs to favor their differentiation.
甲状旁腺激素（PTH）通过其在骨骼和肾脏中的作用来调节血清钙和磷酸盐，并用于骨质疏松症治疗中增加骨量。在骨骼中，PTH作用于成骨细胞和骨细胞以调节骨重塑，同时也作用于骨髓基质细胞（BMSC），调节它们向成骨细胞或脂肪细胞谱系的分化。PTH通过甲状旁腺激素/甲状旁腺激素相关肽（PTHrP）受体发挥作用，该受体是一种G蛋白偶联受体（GPCR），可激活腺苷酸环化酶和磷脂酶C（PLC）。虽然cAMP和PKA的作用已得到充分表征，但关于PLC激活的影响或PTH信号与其他途径之间的相互作用知之甚少。在这里，对PTH处理的小鼠BMSC系（W-20）进行的批量RNA测序揭示了Hippo通路中的显著变化。除了增加其转录外，PTH还通过减少YAP/大肿瘤抑制激酶1（LATS1）相互作用、YAPS127磷酸化和YAP泛素化来稳定YAP蛋白，YAP是Hippo的关键靶点，从而导致YAP核转位和YAP靶基因的表达。类似的事件也发生在骨细胞系中。这是通过Src激酶活性的增加而发生的：我们确定YAPY428是Src响应PTH磷酸化的关键酪氨酸残基。阻止YAPY428磷酸化会导致YAP不稳定，从而阻断W-20细胞的成骨和成脂分化。这些结果证明了PTH/PTHrP与Hippo信号通路之间存在活跃的相互作用，并揭示PTH信号利用PLC/Ca2+/Src酪氨酸激酶信号级联来影响YAP稳定性，拮抗Hippo信号并促进基质细胞分化。因此，PTH信号抵消了Hippo信号在BMSC中的作用，以促进它们的分化。
