scholarly journals Overexpression of SPARC in Human Trabecular Meshwork Increases Intraocular Pressure and Alters Extracellular Matrix

2013 ◽  
Vol 54 (5) ◽  
pp. 3309 ◽  
Author(s):  
Dong-Jin Oh ◽  
Min Hyung Kang ◽  
Yen Hoong Ooi ◽  
Kyu Ryong Choi ◽  
E. Helene Sage ◽  
...  
2020 ◽  
Author(s):  
Sizhen Li ◽  
Qingsong Yang ◽  
Zixiu Zhou ◽  
Min Fu ◽  
Xiaodong Yang ◽  
...  

Abstract Background: Glaucoma is the main reason for irreversible blindness, and pathological increased intraocular pressure is the leading risk factor for glaucoma. It is reported that trabecular meshwork cell injury is closely associated with the elevated intraocular pressure. The current study aimed to investigate the role of SNHG3 in human trabecular meshwork (HTM) cells under oxidative stress. Methods: A series of experiments including real-time quantitative polymerase chain reaction (RT-qPCR), subcellular fractionation assay, western blot analysis, cell counting kit-8 (CCK-8) assay, RNA pull down, flow cytometry analysis, and RIP assay were employed to explore the biological function and regulatory mechanism of SNHG3 in HTM cells under oxidative stress.Results: First, we observed that H2O2 induced SNHG3 upregulation in HTM cells. Then, we found that SNHG3 silencing alleviated H2O2-induced oxidative damage in HTM cells. Moreover, SNAI2 knockdown alleviated the oxidative damage induced by H2O2 in HTM cells. Mechanistically, SNHG3 bound with ELAVL2 to stabilize SNAI2. Finally, SNAI2 overexpression counteracted the effect of SNHG3 silencing on H2O2-induced HTM cells. Conclusion: Our results demonstrated that SNHG3 cooperated with ELAVL2 to modulate cell apoptosis and extracellular matrix (ECM) accumulation by stabilizing SNAI2 in HTM cells under oxidative stress.


2014 ◽  
Vol 33 (4) ◽  
pp. 1215-1224 ◽  
Author(s):  
Huan Zou ◽  
Rongdi Yuan ◽  
Qijun Zheng ◽  
Yan Huo ◽  
Min Lang ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2864
Author(s):  
Avinash Soundararajan ◽  
Sachin Anil Ghag ◽  
Sai Supriya Vuda ◽  
Ting Wang ◽  
Padmanabhan Paranji Pattabiraman

The homeostasis of extracellular matrix (ECM) and actin dynamics in the trabecular meshwork (TM) outflow pathway plays a critical role in intraocular pressure (IOP) regulation. We studied the role of cathepsin K (CTSK), a lysosomal cysteine protease and a potent collagenase, on ECM modulation and actin cytoskeleton rearrangements in the TM outflow pathway and the regulation of IOP. Initially, we found that CTSK was negatively regulated by pathological stressors known to elevate IOP. Further, inactivating CTSK using balicatib, a pharmacological cell-permeable inhibitor of CTSK, resulted in IOP elevation due to increased levels and excessive deposition of ECM-like collagen-1A in the TM outflow pathway. The loss of CTSK activity resulted in actin-bundling via fascin and vinculin reorganization and by inhibiting actin depolymerization via phospho-cofilin. Contrarily, constitutive expression of CTSK decreased ECM and increased actin depolymerization by decreasing phospho-cofilin, negatively regulated the availability of active TGFβ2, and reduced the levels of alpha-smooth muscle actin (αSMA), indicating an antifibrotic action of CTSK. In conclusion, these observations, for the first time, demonstrate the significance of CTSK in IOP regulation by maintaining the ECM homeostasis and actin cytoskeleton-mediated contractile properties of the TM outflow pathway.


Author(s):  
Normie Aida Mohd Nasir ◽  
Renu Agarwal ◽  
Anna Krasilnikova ◽  
Siti Hamimah Sheikh Abdul Kadir ◽  
Igor Iezhitsa

AbstractObjectivesSteroid-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.MethodsHuman 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.ResultsDexamethasone 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.ConclusionsDexamethasone reduces MMP-2 and -9 secretion by HTMCs and this effect of dexamethasone is associated with reduced NFKB phosphorylation and A1AR expression.


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