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

急性一过性炎症对于启动骨愈合、种植体的骨整合、成骨 骨髓间充质干细胞的分化和免疫调节。然而，有害的慢性炎症和骨丢失 (骨溶解)是由不良刺激引起的，包括关节置换产生的磨损副产物(JR)。核子 KappaB因子(NF-κB)是巨噬细胞(mϕ)和骨髓间充质干细胞(MSCs)中的一种关键转录因子，调节 炎症、骨形成/重塑和衰老。我们发现骨髓间充质干细胞可以用脂类进行预适应- 内毒素和肿瘤坏死因子-α诱导急性瞬时激活核因子-αB的实验研究 协同增强成骨作用，并将m-ϕ极化从促炎(M1)调节为 抗炎促再生(M2)表型。此外，抑制持续的NF-κB信号转导 核因子-κB诱骗寡核苷酸可减轻炎症性骨丢失。我们有 转基因间充质干细胞感受核因子-κB的激活并增加抗炎作用的产生 促再生细胞因子IL-4。这项资助的目的是加速净骨的形成和减轻 慢性炎症和骨溶解通过使用预适应或遗传的核因子-kB驱动的免疫调节 将修饰后的MSCs移植到局部环境中。 特定目标#1a-确定预适应与核因子-κB传感的关键免疫调节相互作用 M-ϕ上分泌IL-4的间充质干细胞暴露于穿戴骨科植入物的副产品。 特定目标#1b-通过使用预适应与NF-κB传感和IL-4分泌来促进成骨 在MSCs/mϕ共培养模型中，MSCs暴露于骨科植入物的副产品中。 特定目标#2a--证实移植预适应的MSCs对骨的治疗效果 在急性炎症阶段(模拟假体的初始植入阶段和 骨整合)使用小鼠股骨颗粒持续输注模型。 特定目标#2b--验证预适应与核因子-κB传感和IL-4的治疗效果 在慢性炎症阶段(模拟已建立的磨损)中分泌MSCs的净骨形成 颗粒性疾病)采用小鼠股骨干颗粒持续输注模型。 具体目标#3-证明上述调节急性和慢性炎症的原则是 有效，无论动物性别(雄鼠与雌鼠)或年龄(幼鼠与老年鼠)在体内。我们假设 NF-κB预适应或NF-κB传感和IL-4分泌的骨髓间充质干细胞将促进成骨和 间充质干细胞的免疫调节信号，通过m-ϕ和间充质干细胞的串扰促进骨形成。核因子-kB驱动 骨髓间充质干细胞的免疫调节应减轻颗粒诱导的炎症、破骨细胞的激活，并增强 幼年和老年、雄性和雌性小鼠的骨形成。核因子-kB介导的骨髓间充质干细胞免疫调节是一种新的方法， 机械性的，并直接转化为其他器官系统的炎症性疾病。

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.