甲状腺相关性眼病中PH20诱导CD44v上调对眼外肌纤维化抑制作用的实验研究

甲状腺相关性眼病（TAO）可致眼外肌功能障碍，对视觉功能造成不可逆损害。其发病机制为眼外肌成纤维细胞（EOM-F）介导的透明质酸（HA）堆积和组织纤维化，目前缺乏“一箭双雕”的治疗药物。我们已报道PH20（HA降解酶）可调节HA分子量进而抑制EOM-F增殖。由此猜想PH20或可通过HA调控纤维化，实现降解HA、抑制纤维化的双重目标。预实验表明PH20可提高HA分子量、上调CD44v（HA受体）并抑制纤维化。因此提出假说，PH20通过HA诱导CD44v可发挥抑制纤维化作用。本课题以TAO及正常对照EOM-F为研究对象，观察不同浓度、不同分子量HA对纤维化指标的影响，对比HA作用前后CD44v表达量的变化，分析CD44v表达量与纤维化程度的相关性，检测CD44v干扰后HA对纤维化的作用，探究纤维化相关通路Smad、Akt的磷酸化水平，从而明确HA调控纤维化的分子机制，为抗纤维化治疗提供新思路。

In thyroid associated ophthalmopathy, extraocular muscle dysfunction can irreversibly deteriorate visual function and quality of life. The pathogenesis refers to hyaluronan (HA) accumulation and tissue fibrosis. No drug is available to manage both processes. Extraocular muscle fibroblast (EOM-F), as our research object, is responsible for pathological changes. We have confirmed that hyaluronidase PH20 can not only degrade hyaluronan, but also regulate EOM-F proliferation via alteration of HA polymer size. Therefore, we hypothesize that PH20 may modulate fibrosis through its manipulative effects on HA, and achieve the dual-goal of “anti-HA & anti-fibrosis”. Pre-experiments discovered that PH20 incubation led to up-shift of HA molecular weight, higher expression of CD44v and lower expression of fibrotic markers. According to previous study, CD44, as HA receptor, can mediate fibrotic signaling pathways. Thus, we speculate that antifibrotic effect of PH20 is mediated by CD44v signaling, and CD44v upregulation is mediated by HA polymer size change. In order to explore the relationship between HA and CD44v, we plan to measure the effects of HA (different concentration and polymer size) on CD44v expression. In order to explore the relationship between CD44v and fibrosis, we plan to measure the changes of fibrotic markers after CD44 knockdown. In conclusion, our study aims to uncover the mechanism between HA and fibrosis, offer insights into the therapeutic role of PH20, and provide potential target for antifibrotic therapy.