IADR Abstract Archives
Trb3-Directed Therapy Promotes Bone Regeneration in Osteoporosis
Objectives: Age-related osteoporosis is characterized by abnormal bone modeling due to reduced bone mass and increased marrow fat. Bone regeneration in osteoporosis is hindered by dysregulated differentiation of mesenchymal stem cells (MSCs), favoring adipocytes over osteoblasts. Modulating MSC lineage commitment offers a potential therapeutic strategy for addressing bone loss. We previously identified Trb3 as a critical molecular switch governing MSC lineage fate. This study investigates the role of Trb3 in bone regeneration of osteoporosis.
Methods: A novel modified EM expressing endogenous Trb3 (EMb3) was generated from small molecule-treating MSCs using an extrusion approach. Various molecular techniques were used to assess the osteo- and adipogenic effects of EMb3 at gene and protein levels. The osteogenic effect of EMb3 was assessed in a 3D model by incorporating them into an apatite-PLGA scaffold. A metabolic engineering technique was adopted to enhance bone-targeting ability by conjugating EMb3 with alendronate (ALD-EMb3), a bone-targeting molecule. Bone-binding experiments with Nile-labeled ALD-EMb3 were conducted to test bone-targeting ability. To assess in-vivo bone regeneration, various doses of ALD-EMb3 were injected into ovariectomized mice and evaluated via µCT (n=7).
Results: Our data demonstrated a significant augmentation of endogenous Trb3 expression in EMb3. Moreover, EMb3 displayed increased osteogenesis as shown by elevated osteogenic gene expression, ALP activities, and mineral deposition. Conversely, EMb3 inhibited MSC adipogenesis, indicated by reduced expression of adipogenic markers. EMb3/scaffold complex showed highly cellular viability and increased osteogenesis, along with decreased adipogenesis. Ex vivo bone-binding experiment with a mouse skull bone chip revealed ALD-EMb3 with specific bone targeting ability. µCT images also showed that ALD-EMb3 promotes bone regeneration in OVX mouse as confirmed by quantitative analysis (BMD and BV/TV). Mechanistically, the pro-osteogenic and anti-adipogenic effects of EMb3 was found through stimulating Wnt signaling.
Conclusions: The successful completion of these studies holds potential for transitioning this therapeutic strategy to osteoporotic individuals.
Methods: A novel modified EM expressing endogenous Trb3 (EMb3) was generated from small molecule-treating MSCs using an extrusion approach. Various molecular techniques were used to assess the osteo- and adipogenic effects of EMb3 at gene and protein levels. The osteogenic effect of EMb3 was assessed in a 3D model by incorporating them into an apatite-PLGA scaffold. A metabolic engineering technique was adopted to enhance bone-targeting ability by conjugating EMb3 with alendronate (ALD-EMb3), a bone-targeting molecule. Bone-binding experiments with Nile-labeled ALD-EMb3 were conducted to test bone-targeting ability. To assess in-vivo bone regeneration, various doses of ALD-EMb3 were injected into ovariectomized mice and evaluated via µCT (n=7).
Results: Our data demonstrated a significant augmentation of endogenous Trb3 expression in EMb3. Moreover, EMb3 displayed increased osteogenesis as shown by elevated osteogenic gene expression, ALP activities, and mineral deposition. Conversely, EMb3 inhibited MSC adipogenesis, indicated by reduced expression of adipogenic markers. EMb3/scaffold complex showed highly cellular viability and increased osteogenesis, along with decreased adipogenesis. Ex vivo bone-binding experiment with a mouse skull bone chip revealed ALD-EMb3 with specific bone targeting ability. µCT images also showed that ALD-EMb3 promotes bone regeneration in OVX mouse as confirmed by quantitative analysis (BMD and BV/TV). Mechanistically, the pro-osteogenic and anti-adipogenic effects of EMb3 was found through stimulating Wnt signaling.
Conclusions: The successful completion of these studies holds potential for transitioning this therapeutic strategy to osteoporotic individuals.