Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.
NHC Key Laboratory of Myopia and Related Eye Diseases, Key Laboratory of Myopia and Related Eye Diseases, Chinese Academy of Medical Sciences, Shanghai, China.
Invest Ophthalmol Vis Sci. 2024 Nov 4;65(13):7. doi: 10.1167/iovs.65.13.7.
This study aimed to assess the expression of sterile alpha and TIR motif containing protein 1 (SARM1) in both chronic and acute glaucomatous animal models and investigate the underlying SARM1-JNK signaling mechanism responsible for the protective effects of SARM1 downregulation on retinal ganglion cell (RGC) soma and axons in a chronic intraocular hypertension (COH) model.
The COH model was induced by injecting magnetic microbeads into the anterior chamber, whereas the acute model was created through ischemia-reperfusion (I/R) injury. Immunohistochemistry and Western blot were used to assess SARM1 expression and JNK phosphorylation in the retina and optic nerve. SARM1 downregulation was achieved through the intravitreal injection of adeno-associated virus (AAV)2-shRNA. Quantitative analysis of RGC survival was performed by the counting of Brn3A-positive RGCs, and surviving axons were assessed through optic nerve toluidine blue stain.
The expression of SARM1 increased 1 week after microbead injection in the optic nerve, whereas the retinal SARM1 expression decreased at 3 days post-injection in the COH model. After 24 hours of reperfusion, SARM1 expression increased in both the optic nerves and the retinas in the I/R injury model. SARM1 downregulation led to increased survival of RGC soma and axons in the COH model. In this model, JNK phosphorylation was significantly reduced concomitant with decreased SARM1 expression.
Elevated SARM1 expression was observed in the optic nerves in both the COH and I/R injury models. Downregulation of SARM1 exhibited a protective effect on RGC soma and axons in the COH model, with JNK identified as a downstream regulator of SARM1 in this context.
本研究旨在评估无菌α和 TIR 基序包含蛋白 1（SARM1）在慢性和急性青光眼动物模型中的表达，并研究负责 SARM1 下调对慢性眼内高压（COH）模型中视网膜神经节细胞（RGC）体和轴突的保护作用的潜在 SARM1-JNK 信号机制。
通过在前房内注射磁性微珠诱导 COH 模型，通过缺血再灌注（I/R）损伤建立急性模型。免疫组织化学和 Western blot 用于评估视网膜和视神经中 SARM1 表达和 JNK 磷酸化。通过玻璃体内注射腺相关病毒（AAV）2-shRNA 下调 SARM1。通过 Brn3A 阳性 RGC 的计数对 RGC 存活进行定量分析，通过视神经甲苯胺蓝染色评估存活轴突。
微珠注射后 1 周，视神经中 SARM1 表达增加，而 COH 模型中视网膜 SARM1 表达在注射后 3 天下降。再灌注 24 小时后，I/R 损伤模型中视神经和视网膜中的 SARM1 表达均增加。在 COH 模型中，下调 SARM1 导致 RGC 体和轴突的存活增加。在该模型中，JNK 磷酸化显著降低，同时 SARM1 表达降低。
在 COH 和 I/R 损伤模型中均观察到视神经中 SARM1 表达升高。下调 SARM1 在 COH 模型中对 RGC 体和轴突表现出保护作用，在此背景下，JNK 被鉴定为 SARM1 的下游调节剂。
