血浆外泌体/miR-27a/sFRP1轴调控经典Wnt通路促颌骨放射性骨损伤修复的研究

Mandible radiation bone injury is a common complication after radiotherapy in head and neck cancer pateints. Yet there is no ideal treatment. Targeted gene enhancement techniques for vascularization and bone regeneration represent a new strategy for the treatment of mandible radiation bone injury. The canonical Wnt pathway can upregulate the vascularization and osteogenesis behavior, and we found that plasma exosomes can activate the classical Wnt pathway and promote the normal osteogenesis and angiogenesis, but the mechanism is still not clear. Recent studies suggest that miR-27a, which is enriched in plasma exosomes, is a specific inhibitory miRNA of the canonical Wnt pathway inhibitor sFRP1. Therefore, we propose a scientific hypothesis that the plasma exosomes/miR-27a/sFRP1 axis may activate the canonical Wnt pathway, promote angiogenesis and osteogenesis, and then repair mandible radiation bone injury. We will first construct a murine mandible radiation bone injury model to study the effect of plasma exosomes in the microcirculation and bone regeneration. After that, the interaction between miR-27a/sFRP1 and canonical Wnt pathway will be studied by gene knockout mice and lentivirus. We aim to clarify the function and mechanism of plasma exosomes/miR-27a/sFRP1 axis , and expand the novel application of plasma exosomes in radiation bone injury.

颌骨放射性骨损伤是头颈肿瘤放疗后常见的严重并发症，尚无理想治疗手段。血管新生和骨再生的靶向基因增强技术代表了颌骨放射性骨损伤的治疗新策略。经典Wnt通路可正向调控血管化和成骨行为。申请人前期发现，血浆外泌体可激活经典Wnt通路，促进血管化和成骨，但其机制尚不明确。最新研究提示：血浆外泌体内富含的miR-27a是经典Wnt通路抑制剂sFRP1的特异性抑制miRNA。因此，我们提出科学假设：血浆外泌体/miR-27a/sFRP1轴可能通过激活经典Wnt通路，上调血管化和成骨靶基因蛋白，修复颌骨放射性骨损伤。本课题将构建小鼠颌骨放射性骨损伤模型，研究血浆外泌体对颌骨放射性骨损伤微循环和骨再生的治疗效果；并采用基因敲除小鼠和慢病毒，研究miR-27a及sFRP1与经典Wnt通路的交互作用。从而阐明血浆外泌体/miR-27a/sFRP1轴的功能和机制，并原创性地拓展血浆外泌体在放射性骨损伤中的应用。

头颈部恶性肿瘤患者在接受放疗后出现的正常软、硬组织并发症，是口腔临床常见的疑难病。血浆来源的外泌体具有临床采集方便，生物信息丰富的特点，具有一定的临床应用价值。据此，本课题拟探讨血浆外泌体对放疗后软、硬组织愈合的影响。.本课题建立了放疗后大鼠颅顶骨缺损模型和伤口愈合模型，利用正常大鼠血浆外泌体进行干预。结果表明血浆外泌体可以促进放疗后骨缺损的愈合，促进局部新生血管的形成和骨小梁的再生，并加速放疗后伤口的愈合，推动胞外基质的沉积和改建。通过对放射后成纤维细胞和巨噬细胞的干预，和转录组测序的分析，本课题发现血浆外泌体能够显著促进细胞增殖，并促增殖和血管化相关基因、蛋白的表达。同时，我们还发现，血浆外泌体对铁死亡的调控被证实参与到该过程中。.综上所述，本课题证实血浆外泌体能通过调控放射后成纤维细胞、巨噬细胞增殖等细胞行为，促进放疗后软、硬组织的愈合，并提出了潜在的治疗靶点，为放疗并发症的处理提供了一定实验依据。