Tang Lei, Zhang Jian, Gao Jianping
Department of Ophthalmology, The First People's Hospital of Changde City (Changde Hospital, Xiangya School of Medicine, Central South University), Changde, Hunan, China.
J Diabetes Investig. 2025 Jun 26. doi: 10.1111/jdi.70100.
Mesenchymal stromal/stem cells have neuroprotective effects that limit damage to the retina, which is predominantly mediated by the released extracellular vesicles (EVs). This study aims to investigate the protective effect of adipose-derived mesenchymal stem cell-derived EVs (ADSC-EVs) against pyroptosis of retinal ganglion cells (RGCs).
ADSC-EVs were isolated and then characterized. Mouse primary RGCs exposed to high glucose (HG) were applied for in vitro experiments. miR-26a-5p expression in RGCs after ADSC-EV treatment was determined by RT-qPCR. Target relation between miR-26a-5p and histone deacetylase 4 (HDAC4) was identified by luciferase reporter assay. miR-26a-5p blockad and HDAC4 ectopic expression experiments were conducted to clarify their functions in the pyroptosis of RGCs. The pyroptosis-associated protein GSDMD-N, inflammatory factors, and cell death were further evaluated by western blot, ELISA, and LDH assays, respectively.
Exposure to HG reduced RGC viability and increased cell death, GSDMD-N protein level, and IL-1β and IL-18 levels, indicating pyroptosis induction. However, these HG-caused alterations could be reversed by ADSC-EVs. ADSC-EVs transferred miR-26a-5p into RGCs where miR-26a-5p targeted HDAC4 to limit its expression and enhance histone H3 lysine 27 acetylation (H3K27ac) modification at the nuclear factor erythroid 2-related factor 2 (Nrf2) promoter region. This effect contributed to increases in Nrf2 protein level and nuclear translocation. Importantly, decreased H3K27ac modification at the Nrf2 promoter region could partially abrogate the inhibiting effect of ADSC-EVs on HG-induced RGC pyroptosis.
Overall, our findings reveal the beneficial effects of ADSC-EVs shuttling miR-26a-5p on HG-induced RGCs and determine a potential mechanism responsible for pyroptosis.
间充质基质/干细胞具有神经保护作用，可限制视网膜损伤，这主要由释放的细胞外囊泡（EVs）介导。本研究旨在探讨脂肪来源的间充质干细胞衍生的细胞外囊泡（ADSC-EVs）对视网膜神经节细胞（RGCs）焦亡的保护作用。
分离并鉴定ADSC-EVs。将暴露于高糖（HG）的小鼠原代RGCs用于体外实验。通过RT-qPCR测定ADSC-EV处理后RGCs中miR-26a-5p的表达。通过荧光素酶报告基因测定法鉴定miR-26a-5p与组蛋白去乙酰化酶4（HDAC4）之间的靶向关系。进行miR-26a-5p阻断和HDAC4异位表达实验，以阐明它们在RGCs焦亡中的作用。分别通过蛋白质免疫印迹法、酶联免疫吸附测定法和乳酸脱氢酶测定法进一步评估焦亡相关蛋白GSDMD-N、炎症因子和细胞死亡情况。
暴露于HG会降低RGCs的活力，增加细胞死亡、GSDMD-N蛋白水平以及IL-1β和IL-18水平，表明诱导了焦亡。然而，这些由HG引起的改变可被ADSC-EVs逆转。ADSC-EVs将miR-26a-5p转运至RGCs中，在其中miR-26a-5p靶向HDAC4以限制其表达，并增强核因子红细胞2相关因子2（Nrf2）启动子区域的组蛋白H3赖氨酸27乙酰化（H3K27ac）修饰。这种作用导致Nrf2蛋白水平升高和核转位增加。重要的是，Nrf2启动子区域H3K27ac修饰的降低可部分消除ADSC-EVs对HG诱导的RGCs焦亡的抑制作用。
总体而言，我们的研究结果揭示了携带miR-26a-5p的ADSC-EVs对HG诱导的RGCs的有益作用，并确定了一种与焦亡相关的潜在机制。
