Enhanced Bone Healing Around Implants by Transplanted NF-kB Driven Immunomodulating MSCs

急性短暂性炎症对于骨愈合、植入物的骨整合、成骨细胞的形成和骨形成的启动是至关重要的。 MSC的分化和免疫调节。然而，有害的慢性炎症和骨质流失 （骨质溶解）是由不利刺激引起的，包括关节置换（JR）的磨损副产物。核 因子κ B（NF-κB）是巨噬细胞和间充质干细胞中的一种重要转录因子， 炎症、骨形成/重塑和老化。我们发现用脂多糖预处理MSCs， 糖（LPS）和肿瘤坏死因子-α（TNF-α）诱导NF-κB B的急性瞬时活化 协同地增强骨生成，并将肌细胞极化从促炎性（M1）调节为促炎性（M2）。 抗炎促再生（M2）表型。此外，使用抗肿瘤药物抑制持续的NF-κB信号传导， 显示NF-κB诱饵寡脱氧核苷酸（ODN）减轻炎性骨丢失。我们有 基因修饰的MSC感知NF-κB活化，然后增加抗炎因子的产生， 促再生细胞因子IL-4。该补助金的目的是加速净骨形成， 通过使用预处理或遗传修饰的NF-κ B驱动的免疫调节的慢性炎症和骨质溶解 将修饰的MSC移植到局部环境中。 具体目的#1a -定义预处理与NF-κB传感的关键免疫调节相互作用 和IL-4分泌的MSC在暴露于矫形植入物的磨损副产物的小鼠上。 具体目标#1 B-通过使用预处理与NF-κB传感和IL-4分泌增强骨生成 MSC/骨髓基质细胞共培养模型中的MSC暴露于骨科植入物的磨损副产物。 具体目的#2a -证明移植的预处理MSC对骨的治疗作用 在急性炎症阶段（模拟假体的初始植入阶段， 骨整合）。 具体目的#2 B-证明预处理与NF-κB传感和IL-4的治疗作用 在慢性炎症阶段（模拟已建立的磨损）期间分泌MSC对网状骨形成的影响 颗粒病）。 具体目标#3 -证明上述调节急性和慢性炎症的原理是 无论动物性别（雄性小鼠vs.雌性小鼠）或年龄（年轻小鼠vs.老年小鼠），体内均有效。我们假设 NF-κB预处理或NF-κB敏感和IL-4分泌的MSC将促进成骨和成纤维细胞增殖， MSC的免疫调节信号传导，通过MSC和MSC的串扰增强骨形成。NF-kB驱动 MSC的免疫调节应减轻颗粒诱导的炎症、破骨细胞活化，并增强 年轻和年老的雄性和雌性小鼠的骨形成。NF-kB驱动的MSC的免疫调节是新颖的， 机制，并直接转化为其他器官系统中的炎症性疾病。

Acute transient inflammation is crucial for initiation of bone healing, osseointegration of implants, osteogenic differentiation of MSCs, and immunomodulation. However, harmful chronic inflammation and bone loss (osteolysis) are induced by adverse stimuli including wear byproducts from joint replacements (JR). Nuclear Factor kappa B (NF-κB) is a critical transcription factor in both macrophages (mϕ) and MSCs that regulates inflammation, bone formation/remodeling, and aging. We showed that preconditioning MSCs with lipopoly- saccharide (LPS) and tumor necrosis factor-α (TNF-α) to induce acute transient activation of NF-κB synergistically enhances osteogenesis, and modulates mϕ polarization from a pro-inflammatory (M1) to an anti-inflammatory pro-regenerative (M2) phenotype. Furthermore, inhibition of persistent NF-κB signaling using an NF-κB decoy OligoDeoxyNucleotide (ODN) was shown to mitigate inflammatory bone loss. We have genetically modified MSCs to sense NF-κB activation and then increase production of the anti-inflammatory pro-regenerative cytokine IL-4. The purpose of this grant is to accelerate net bone formation and mitigate chronic inflammation and osteolysis via NF-kB driven immunomodulation using preconditioned or genetically modified MSCs transplanted to the local environment. Specific Aim #1a -To define the critical immunomodulatory interactions of preconditioned vs. NF-κB sensing and IL-4 secreting MSCs on mϕ exposed to wear byproducts from orthopaedic implants. Specific Aim #1b - To enhance osteogenesis by using preconditioned vs. NF-κB sensing and IL-4 secreting MSCs in an MSC/mϕ co-culture model exposed to wear byproducts from orthopaedic implants. Specific Aim #2a - To demonstrate the therapeutic effects of transplanted preconditioned MSCs on bone during the acute inflammatory stage (simulating the stage of initial implantation of a prosthesis and osseointegration) using the murine continuous femoral particle infusion model. Specific Aim #2b - To demonstrate the therapeutic effects of preconditioned vs. NF-κB sensing and IL-4 secreting MSCs on net bone formation during the chronic inflammatory stage (simulating established wear particle disease) using the murine continuous femoral particle infusion model. Specific Aim #3 - To demonstrate that the above principles of modulating acute and chronic inflammation are valid irrespective of animal sex (male vs. female mice) or age (young vs. elderly mice) in vivo. We hypothesize that NF-κB preconditioning or NF-κB sensing and IL-4 secreting MSCs will enhance the osteogenic and immunomodulatory signaling of MSCs, enhancing bone formation via crosstalk by mϕ and MSCs. NF-kB driven immunomodulation of MSCs should mitigate particle-induced inflammation, osteoclast activation, and enhance bone formation in young and aged, male and female mice. NF-kB driven immune modulation of MSCs is novel, mechanistic, and directly translational to inflammatory disorders in other organ systems.