TET3去甲基化途径介导HIF-1α活化PARKIN依赖线粒体自噬调控烧伤创面早期进展的作用及机制研究

Burn wounds are not usually stable and undergo a dynamic progress that results in the deepening and expansion of the initial burn area, a process also defined as burn-wound progression. The zone of stasis has a higher risk of deterioration and is regarded as a key region contributing to early burn-wound progression, and it is meaningful to study the inner protective mechanism involved in the development of tissue injury in this zone. Mitophagy was regarded as an important routine to eliminate damaged mitochondria and related increase of oxidative damages and apoptosis, which contributes to the relief of tissue injury in the zone of stasis. However, there is no detail clarified about the protective mechanism and involved regulators of mitophagy to burn-wound progression. Recently, we observed tissue hypoxia in the zone of stasis induced an “increase to decrease” expression alteration of HIF-1α, which tendency was similar to the time-related changes of mitophagy but opposite to trauma progression in the zone of stasis, and its regulation mainly targeted PARKIN receptor. Moreover, HIF-1α might regulate the transcription and expression of PARKIN via TET3/5-hmC hydroxymethylation axis. It is still unclear about detailed mechanism on abovementioned results. Accordingly, we hypothesized that HIF-1α ameliorates burn-wound progression through activating PARKIN-dependent mitophagy with the involvement of TET3-mediated DNA demethylation. This study aims to illuminate the detailed effect and mechanism of HIF-1α on mitophagy and deterioration of the zone of stasis with involvement of the TET3 routine and PARKIN receptor in an in vitro fibroblast hypoxic model and an in vivo rat burn model, which will provide a new way for further treatment on burn-wound progression.

烧伤创面早期不稳定，可进展性扩大、加深，淤滞区是关键变化区域，研究该区域的损伤保护机制对提高疗效、改善预后意义重大。线粒体自噬可清除受损线粒体以减少氧化应激、细胞凋亡等机制动员，是缓解淤滞区损伤加重的潜在途径，但调控其活化的关键因子及分子机制尚不明确。新近，我们发现伤后淤滞区组织缺氧诱导HIF-1α呈先增后降的表达变化，与损伤持续加重趋势相反，而与线粒体自噬相关联，PARKIN受体是潜在靶标；另发现，TET3/5-hmC羟甲基化轴可能参与HIF-1α调控PARKIN的转录表达，但机制细节仍未阐明。我们推测，HIF-1α通过TET3 DNA去甲基化途径活化PAKRIN依赖线粒体自噬来影响烧伤创面早期进展。本研究拟利用成纤维细胞低氧模型及大鼠烧伤模型从体内、外两个层面，重点关注TET3途径及PARKIN受体，以期阐明基于线粒体自噬的HIF-1α调控烧伤创面损伤进展的分子机制，为治疗提供新思路。

烧伤创面早期不稳定，存在扩大、加深的进展过程，淤滞区是关键变化区域，研究该区域的病理生理机制对保护创面、改善预后具有重要意义。本研究利用大鼠动物模型模拟烧伤后创面的早期病理生理变化过程，通过激光血流监测、病理、分子生物学检测等技术方法，评估并首次验证了伤后创面组织内缺血缺氧刺激通过HIF-1a/TET3途径调节PARKIN依赖线粒体自噬活化，进而调控烧伤创面损伤进展相关损伤机制激活的具体作用及机制。本研究聚焦于烧伤创面早期的动态进展过程，由机体内源性自保护机制出发，创新性地从线粒体自噬的角度，深入研究细胞器应激在烧伤创面阻滞区损伤进展中的作用机制和干预靶点，利用各种手段，为烧伤创面早期持续进展的机制提供理论阐述，并在国际上率先原创性提出烧伤创面内的线粒体自噬局部活化在调控烧伤早期进展中有重要参与地位，是机体对抗烧伤后早期损伤应激重要且极具潜力的内源性保护机制，研究内容具有较强创新性和独特性。该研究所关注的为烧伤领域常见且亟需解决的关键问题，具有较高的科学研究价值，项目的研究结果将引领并推动烧伤创面早期持续进展机制研究，进一步丰富烧伤早期损伤的治疗手段，提供多层次的诊疗空间。