Characterization of TGF-β by Induced Oxidative Stress in Human Trabecular Meshwork Cells

Abstract

Oxidative stress generated by reactive oxygen species (ROS) plays a critical role in the pathomechanism of glaucoma, which is a multifactorial blinding disease that may cause irreversible damage within human trabecular meshwork cells (HTMCs). It is known that the transforming growth factor-β (TGF-β) signaling pathway is an important component of oxidative stress-induced damage related to extracellular matrix (ECM) fibrosis and activates cell antioxidative mechanisms. To elucidate the dual potential roles and regulatory mechanisms of TGF-β in effects on HTMCs, we established an in vitro oxidative model using hydrogen peroxide (H2O2) and further focused on TGF-β-related oxidative stress pathways and the related signal transduction. Via a series of cell functional qualitative analyses to detect related protein level alterations and cell fibrosis status, we illustrated the role of TGF-β1 and TGF-β2 in oxidative stress-induced injury by shTGF-β1 and shTGF-β2 knockdown or added recombinant human TGF-β1 protein (rhTGF-β1). The results of protein level showed that p38 MAPK, TGF-β, and its related SMAD family were activated after H2O2 stimulation. Cell functional assays showed that HTMCs with H2O2 exposure duration had a more irregular actin architecture compared to normal TM cells. Data with rhTGF-β1 (1 ng/mL) pretreatment reduced the cell apoptosis rate and amount of reactive oxygen species (ROS), while it also enhanced survival. Furthermore, TGF-β1 and TGF-β2 in terms of antioxidant signaling were related to the activation of collagen I and laminin, which are fibrosis-response proteins. Succinctly, our study demonstrated that low concentrations of TGF-β1 (1 ng/mL) preserves HTMCs from free radical-mediated injury by p-p38 MAPK level and p-AKT signaling balance, presenting a signaling transduction mechanism of TGF-β1 in HTMC oxidative stress-related therapies.

An α2-Adrenergic Agonist, Brimonidine, Beneficially Affects the TGF-β2-Treated Cellular Properties in an In Vitro Culture Model

“…For the evaluation of the drug efficacy of brimonidine (BRI), an α2-adrenergic agonist on TGF-β2 (5 ng/mL)-treated HTM cells (2D and 3D) 10 μM BRI were supplemented on cell culture day 1. The drug concentrations were confirmed as the optimal concentrations based on previous studies [ 11 , 13 , 14 ], and a cell viability analysis of BRI using retinal pigment epithelium cells [ 15 ].…”

Tibetan Medicine Shi-Wei-Gan-Ning-San Alleviates Carbon Tetrachloride-Induced Chronic Liver Injury by Inhibiting TGF-β1 in Wistar Rats

“…Especially in the CCl 4 -induced liver injury model, several studies indicate that natural products can alleviate tissue injury by modulating immune responses and oxidative stress [43][44][45][46]. TGF-β1 is well known for regulating inflammation and oxidative stress [47,48]. In other words, TGF-β1 can be associated with the process of liver injury by mediating inflammation and oxidative stress, for example, downregulation of miR-10a can suppress sepsis-induced liver injury by downregulating the TGF-β1 pathway, as well as inflammation and oxidative stress [49].…”

Genome-wide transcriptome profiling of human trabecular meshwork cells treated with TGF-β2

“…In podocytes TGF-β induces the synthesis and release of EDN1 which initiates mitochondrial ROS, mitochondrial DNA damage and mitochondrial dysfunction 68 . Similarly, there is an interplay between ROS and TGF-β in glaucoma 69 , and NOX4 is one of the major sources of cellular oxidative stress and is an important downstream effector in mediating TGF-β-induced fibrosis in the heart, lungs and kidneys via the production of ROS 70 . NOX4 was significantly upregulated by TGF-β2 in our study and has been demonstrated to drive ECM production, actin stress fibre formation and αSMA expression in the TM 71 .…”