DJ-1调控Keap1-Nrf2-ARE通路在噪声致耳蜗毛细胞损伤中的保护作用及分子机制研究

Noise-induced hearing loss has become an important scientific problems that threating to human health. The previous studies have shown that reactive oxygen species play a key role in the occurrence and development process of noise-induced hearing loss, and it can relieve cochlear hair cells injury by inhibition of oxidative stress-resistance related factor Nrf2 and ERK2 expression, so as to improve hearing level. DJ-1 is the important regulatory factor of antioxidant pathways Keap1-Nrf2-ARE. It can promote neural cells survival and avoid cell oxidative stress damage. However, its relationship with noise-induced hearing loss has not yet been elucidated. We infer that “DJ-1 protects cochlear hair cells from oxidative stress-related damage through Keap1-Nrf2-ARE ways”. In order to verify the hypothesis, this project intends to use DJ-1 knockout mice and clinical specimens; and further explore the role of DJ-1 in cochlear hair cells beating oxidative stress damage through adenovirus transfection, RNA interference and western blot method; and provide therapeutic idea for targeting DJ-1 treatment. Through the GST pull-down and co-immunoprecipitation technology, it will be confirmed that DJ-1/Keap1-Nrf2-ARE way regulates the molecular mechanism of noise-induced hearing loss, providing theoretical basis for the prevention and treatment of noise-induced hearing loss.

噪声性耳聋已经成为威胁人类健康的重大科学问题，研究表明，活性氧在噪声性耳聋发生发展过程中起关键作用，通过抑制抗氧化应激的相关因子Nrf2、ERK2的表达可以减轻耳蜗毛细胞的损伤，从而改善听力水平。DJ-1是抗氧化通路Keap1-Nrf2-ARE的重要调节因子，能够促进神经细胞存活，避免细胞的氧化应激损伤，但是其与噪声性耳聋的关系尚未阐明。我们推断“DJ-1通过Keap1-Nrf2-ARE途径调控耳蜗毛细胞避免氧化应激损伤”。为证实该假说，本项目拟采用DJ-1基因敲除小鼠、临床标本等研究模型，通过腺病毒转染技术、RNA干扰、免疫印迹等方法，探讨DJ-1在噪声性耳聋耳蜗毛细胞抗氧化应激损伤中的作用，提供以DJ-1为靶向的治疗思路；通过GST pull-down和免疫沉淀技术，阐明DJ-1/Keap1-Nrf2-ARE途径调节噪声性耳聋的分子机制，为噪声性耳聋的防治提供理论依据。

噪声是人们日常生活和工作中最常遭受的环境暴露，其最常见的危害是引起噪声性耳聋。研究表明氧化应激是噪声引起毛细胞损害的主要原因，强噪声可引起耳蜗血管收缩，导致组织缺氧、缺血，影响组织局部有氧代谢，使耳蜗内产生大量活性氧等自由基。本研究应用HEI-OC1细胞和氧化应激诱导剂模拟体内氧化应激的微环境，研究DJ-1在耳蜗毛细胞氧化应激中的作用，结果表明DJ-1通过降低自由基产生的氧化应激能力保护耳蜗HEI-OC1细胞免受诱导氧化应激源的影响。在体观察过表达DJ-1对噪声暴露听功能水平的影响，结果表明DJ-1对噪声性听力损失和毛细胞丢失有一定的保护作用，能够降低噪声后听性脑干反应和耳声发射阈值，对高频区域外毛细胞有保护作用。此外，本研究初步探索了DJ-1和Nrf2的相互作用在DJ-1防治噪声性耳聋的作用，及DJ-1防治噪声性耳聋的机理。结果表明，在噪声性耳聋中，DJ-1通过Keap1-Nrf2-ARE信号通路激活下游的抗氧化应激因子，从而减轻耳蜗毛细胞对氧化应激的损伤。本项目研究成果为噪声性耳聋的防治开创了新思路。