Dataset Information

TGF-Beta Receptor II Is Critical for Osteogenic Progenitor Cell Proliferation and Differentiation During Postnatal Alveolar Bone Formation.

ABSTRACT: Transforming growth factor beta (TGFβ) signaling plays an important role during osteogenesis. However, most research in this area focuses on cortical and trabecular bone, whereas alveolar bone is largely overlooked. To address the role of TGFβR2 (the key receptor for TGFβ signaling) during postnatal alveolar bone development, we conditionally deleted Tgfβr2 in early mesenchymal progenitors by crossing Gli1-Cre ^ERT2; Tgfβr2 ^flox/flox ; R26R ^tdTomato mice (named early cKO) or in osteoblasts by crossing 3.2kb Col1-Cre ^ERT2 ; Tgfβr2 ^flox/flox ; R26R ^tdTomato mice (named late cKO). Both cKO lines were induced at postnatal day 5 (P5) and mice were harvested at P28. Compared to the control littermates, early cKO mice exhibited significant reduction in alveolar bone mass and bone mineral density, with drastic defects in the periodontal ligament (PDL); conversely, the late cKO mice displayed very minor changes in alveolar bone. Mechanism studies showed a significant reduction in PCNA+ PDL cell numbers and OSX+ alveolar bone cell numbers, as well as disorganized PDL fibers with a great reduction in periostin (the most abundant extracellular matrix protein) on both mRNA and protein levels. We also showed a drastic reduction in β-catenin in the early cKO PDL and a great increase in SOST (a potent inhibitor of Wnt signaling). Based on these findings, we conclude that TGFβ signaling plays critical roles during early alveolar bone formation via the promotion of PDL mesenchymal progenitor proliferation and differentiation mechanisms.

SUBMITTER: Xu C

PROVIDER: S-EPMC8497707 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundAdipose-derived stem cells (ADSCs) are an attractive cell source for bone tissue engineering and have great potential for bone regeneration and defect repair. The transcriptional coactivator with PDZ-binding motif (TAZ) has been demonstrated to modulate osteogenic and adipogenic differentiation of mesenchymal stem cells. However, its roles during ADSC differentiation and therapeutic potentials for bone regeneration have as yet not been well established.MethodsTAZ expression was measured during osteogenic differentiation of ADSCs in vitro. Both loss-of-function and gain-of-function approaches by TAZ knockdown or enforced overexpression were utilized to determine its functions during osteogenic differentiation of ADSCs. TM-25659, a chemical activator of TAZ, was used to determine whether pharmacological activation of TAZ in ADSCs enhanced osteogenic differentiation in vitro and bone formation in animal models. The molecular mechanisms underlying TAZ in promoting osteogenesis of ADSCs were also explored.ResultsIncreased TAZ expression was observed during osteogenic differentiation of human ADSCs. TAZ knockdown resulted in compromised osteogenic differentiation and enhanced adipogenic differentiation of ADSCs. In contrast, enforced TAZ overexpression yielded increased osteogenic differentiation and bone regeneration in vivo, and impaired adipogenic differentiation of ADSCs. Pharmacological activation of TAZ by its chemical activator TM-25659 facilitated osteogenic differentiation of ADSCs. Noticeably, transient treatment of ADSCs with TM-25659 or intraperitoneal injection of TM-25659 significantly enhanced bone regeneration of ADSCs loaded with porous ?-TCP in vivo. Mechanistically, TM-25659 exposure significantly promoted TAZ phosphorylation and nuclear translocation, and potentiated the assembly of the TAZ-Runx2 complex. Subsequently, the TAZ-Runx2 complex was further recruited to the promoter of osteocalcin and in turn enhanced its transcription.ConclusionsOur findings indicate that TAZ is a key mediator that promotes ADSC commitment to the osteoblast lineage. Pharmacological activation of TAZ in ADSCs might become a feasible and promising approach to enhance bone regeneration and repair.

Project description:Bone sialoprotein (BSP) is an extracellular matrix (ECM) protein associated with mineralized tissues, particularly bone and cementum. BSP includes functional domains implicated in collagen binding, hydroxyapatite nucleation, and cell signaling, although its function(s) in osteoblast and osteoclast differentiation and function remain incompletely understood. Genetic ablation of BSP in Ibsp knockout (Ibsp-/-) mice results in developmental bone mineralization and remodeling defects, with alveolar bone more severely affected than the femurs and tibias of the postcranial skeleton. The role of BSP in alveolar bone healing has not been studied. We hypothesized that BSP ablation would cause defective alveolar bone healing. We employed a maxillary first molar extraction socket healing model in 42-d postnatalIbsp-/- and wild-type (WT) control mice. Tissues were collected at 0, 7, 14, 21, and 56 d postprocedure (dpp) for analysis by micro-computed tomography (microCT), histology, in situ hybridization (ISH), immunohistochemistry (IHC), and quantitative polymerase chain reaction (qPCR) array. As expected, alveolar bone healing progressed in WT mice with increasing bone volume fraction (BV/TV), bone mineral density (BMD), and tissue mineral density (TMD), transitioning from woven to mature bone from 7 to 56 dpp. Ibsp messenger RNA (mRNA) and BSP protein were strongly expressed during alveolar bone healing in parallel with other osteogenic markers. Compared to WT, Ibsp-/- mice exhibited 50% to 70% reduced BV/TV and BMD at all time points, 7% reduced TMD at 21 dpp, abnormally increased Col1a1 and Alpl mRNA expression, and persistent presence of woven bone and increased bone marrow in healing sockets. qPCR revealed substantially dysregulated gene expression in alveolar bone of Ibsp-/- versus WT mice, with significantly disrupted expression of 45% of tested genes in functional groups, including markers for osteoblasts, osteoclasts, mineralization, ECM, cell signaling, and inflammation. We conclude that BSP is a critical and nonredundant factor for alveolar bone healing, and its absence disrupts multiple major pathways involved in appropriate healing.

Dataset Information

TGF-Beta Receptor II Is Critical for Osteogenic Progenitor Cell Proliferation and Differentiation During Postnatal Alveolar Bone Formation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets