HDAC1双向调控在脐带MSCs向神经元样细胞定向分化过程中的作用和机制研究

Spinal cord injury (SCI) is a disease with high mobility and mortality, for which there is no effective treatment in clinic, yet researching on stem cells brings new hope to SCI. The prior problems to be resolved are to discover the key factors regulating neuronal differentiation and promote the efficiency of neuronal differentiation of MSCs. Recently, it has been discovered that histone acetylation plays an important role in the proliferation and differentiation of stem cells. However, the effects and mechanisms of the bi-directional regulation of histone deacetylase 1 (HDAC1) on the differentiation of umbilical cord MSCs into neuron-like cells are still not understood. In this study, we will use flow cytometry, qRT-PCR, Western, immunofluorescence, ChIP-on-chip and bioinformatics analysis in vivo and vitro to observe the effect of the bi-directional regulation of HDAC1 on the differentiation of umbilical cord MSCs into neuron-like cells under neural induction microenvironment, meanwhile, to explore and discuss the roles and mechanisms of histone acetylation in the differentiation of MSCs. This research will provide theoretical basis for revealing the molecular mechanisms of the differentiation of MSCs into neuron-like cells, and lay foundation for improving the effect of MSCs in the treatment for SCI and other neurological diseases, which is of profound research significance and broad application prospect.

脊髓损伤（SCI）致残率和死亡率高，临床上无特效疗法，干细胞为其治疗带来希望。寻找调控神经分化的关键因子、提高MSCs神经分化效率是亟待解决的问题。近年发现组蛋白乙酰化修饰在干细胞增殖和分化中发挥重要作用，但是组蛋白去乙酰化酶1（HDAC1）的双向调控在脐带MSCs增殖和向神经元样细胞定向分化中的作用和分子机制还不清楚。因此，本项目拟采用流式细胞术、qRT-PCR、Western、免疫荧光、ChIP-on-chip及生物信息学分析等技术，通过体外和体内实验观察神经诱导微环境下，HDAC1的双向调控对脐带MSCs向神经元样细胞定向分化的影响，并初步探讨乙酰化修饰在MSCs成神经分化中的作用和机制。本项目的研究为揭示MSCs向神经元样细胞分化的分子机制提供理论依据，同时为提高MSCs在SCI等神经系统疾病的临床治疗效果奠定基础，具有深远的研究意义和广阔的应用前景。

干细胞为脑损伤、脊髓损伤等神经疾病的治疗带来希望，但是干细胞在损伤部位的存活和神经分化效率低。因此，寻找调控神经分化的关键因子、提高MSCs神经分化效率和疗效是亟需解决的关键问题。组蛋白乙酰化修饰在干细胞增殖、分化以及神经损伤修复中发挥关键作用。但是组蛋白去乙酰化酶1（HDAC1）在脐带或骨髓MSCs增殖和向神经元样细胞定向分化中的作用和分子机制还不清楚。本研究旨在通过体内外实验检测HDAC1表达下调对脐带或骨髓MSCs增殖、神经分化及其治疗脑损伤或脊髓损伤效果的影响。我们发现使用siHDAC1靶向下调HDAC1表达可以在体外调控脐带MSCs的增殖、凋亡、迁移，并且通过激活BDNF-TrkB-CREB通路促进hUC-MSCs的神经分化。体内研究显示MSC-siHDAC1移植后可改善TBI小鼠的运动功能和认知功能，减轻脑水肿、减小损伤体积和神经凋亡，促进SGZ区的神经再生，其作用与PI3K/AKT通路的激活有关。另一方面，我们使用曲古霉素A（TSA）抑制HDAC1的表达。我们发现TSA预处理可以提高hUC-MSCs乙酰化水平，促进hUC-MSCs的迁移和神经分化，并提高hUC-MSCs移植对TBI小鼠的神经修复和保护作用。此外，TSA能够激活Nrf2/ARE通路，促进BMSC移植对脊髓损伤小鼠的神经保护作用，其作用主要表现在改善神经功能、降低损伤部位氧化水平，促进神经再生等。这些结果表明HDAC1表达下调可以在体内外水平促进脐带或骨髓MSCs的存活和神经分化，并增强MSCs对脑损伤或脊髓损伤的神经修复和神经保护作用。因此，组蛋白乙酰化修饰联合干细胞可以为脑损伤或脊髓损伤提供一种有效的治疗方式。