Center for Neuroscience Research, Faculty of Medicine, Universiti Teknologi MARA (UiTM), Sungai Buloh Campus, Sungai Buloh, Selangor, Malaysia.
Institute of Medical Molecular Biotechnology (IMMB), Universiti Teknologi MARA (UiTM), Sungai Buloh Campus, Sungai Buloh, Selangor, Malaysia.
J Basic Clin Physiol Pharmacol. 2020 Jul 22;31(6):jbcpp-2019-0373. doi: 10.1515/jbcpp-2019-0373.
Objectives Steroid-induced ocular hypertension and glaucoma are associated with extracellular matrix remodeling at the trabecular meshwork (TM) of the eye due to reduced secretion of matrix metalloproteinases (MMPs), a family of enzymes regulating extracellular matrix proteolysis. Several biological functions of steroids are known to involve regulation of adenosine A1 receptors (A1AR) and nuclear factor kappa B (NFKB). Since MMPs expression in TM has been shown to be regulated by A1AR as well as transcription factors, it is likely that dexamethasone-induced changes in aqueous humor dynamics involve reduced MMP and A1AR expression and reduced NFKB activation. Hence, the current study investigated the association of dexamethasone-induced reduction in MMP secretion with reduced NFKB activation and A1AR expression. Methods Human trabecular meshwork cells (HTMCs) were characterized by estimating myocilin and alpha smooth muscle actin expression and then were treated with dexamethasone 100 nM for 2, 5 and 7 days. The MMP secretion was estimated in culture media using Western blot. Immunocytochemistry (ICC) and ELISA were done to investigate the effect of dexamethasone on NFKB phosphorylation. A1AR expression in HTMCs was determined using Western blot and ELISA. Results Dexamethasone caused a significant reduction in both MMP-2 and -9 expression compared to untreated group after five and seven days but not after two days of culture. Significantly reduced phosphorylated NFKB and A1AR protein levels were detected in dexamethasone treated compared to vehicle treated HTMCs after five days of culture. Conclusions Dexamethasone reduces MMP-2 and -9 secretion by HTMCs and this effect of dexamethasone is associated with reduced NFKB phosphorylation and A1AR expression.
由于基质金属蛋白酶（MMPs）的分泌减少，细胞外基质重塑与类固醇诱导的眼内压升高和青光眼有关，MMPs 是调节细胞外基质蛋白水解的酶家族。已知类固醇的几种生物学功能涉及调节腺苷 A1 受体（A1AR）和核因子 kappa B（NFKB）。由于已经表明 MMP 在 TM 中的表达受 A1AR 以及转录因子调节，因此，地塞米松诱导的房水动力学变化可能涉及 MMP 和 A1AR 表达减少以及 NFKB 激活减少。因此，本研究调查了地塞米松诱导的 MMP 分泌减少与 NFKB 激活和 A1AR 表达减少之间的关联。
通过估计肌球蛋白和α平滑肌肌动蛋白的表达来鉴定人眼小梁细胞（HTMC），然后用 100 nM 地塞米松处理 HTMC 2、5 和 7 天。使用 Western blot 在培养基中估计 MMP 分泌。免疫细胞化学（ICC）和 ELISA 用于研究地塞米松对 NFKB 磷酸化的影响。使用 Western blot 和 ELISA 确定 HTMC 中的 A1AR 表达。
与未处理组相比，地塞米松处理 5 天和 7 天后，MMP-2 和 MMP-9 的表达均显著降低，但培养 2 天后则没有。与载体处理的 HTMC 相比，在培养 5 天后，地塞米松处理的 HTMC 中检测到磷酸化 NFKB 和 A1AR 蛋白水平显著降低。
地塞米松减少 HTMC 中 MMP-2 和 MMP-9 的分泌，这种地塞米松的作用与 NFKB 磷酸化和 A1AR 表达减少有关。
