Effect of cytoglobin overexpression on extracellular matrix component synthesis in human tenon fibroblasts

Sulforaphane inhibits TGF-β-induced fibrogenesis and inflammation in human Tenon's fibroblasts

Purpose

Subconjunctival fibrosis is the main cause of failure after glaucoma filtration surgery. We explored the effects of sulforaphane (SFN) on the conversion of human Tenon's fibroblasts (HTFs) into myofibroblasts, transforming growth factor (TGF)-β-induced contraction of collagen gel, and inflammation.

Methods

After treatment with the combination of TGF-β and SFN or TGF-β alone, primary HTFs were subjected to a three-dimensional collagen contraction experiment to examine their contractility. Levels of α smooth muscle actin (α-SMA), synthesis of extracellular matrix (ECM), and phosphorylation of various signaling molecules were determined by western blot or quantitative reverse transcription-polymerase chain reaction (RT-qPCR). Fluorescence microscopy was employed to examine stress fiber formation in HTFs. The expressions of interleukin (IL)-6, IL-8, and connective tissue growth factor (CTGF) were determined using RT-qPCR.

Results

The contraction of myofibroblasts caused by TGF-β was significantly suppressed by SFN. This suppressive effect was exerted via the differentiation of HTFs into myofibroblasts by inhibiting the production of fibronectin and the expression of α-SMA. Moreover, SFN treatment reduced the expression of TGF-β-promoted integrins β1 and α5, myosin light chain (MLC) phosphorylation, and stress fiber formation, as well as the expression of IL-6, IL-8, and CTGF. Finally, TGF-β-induced Smad2/3 and extracellular signal-regulated kinase (ERK) phosphorylations were attenuated by SFN.

Conclusions

SFN inhibits HTF contractility, differentiation into myofibroblasts, and inflammation caused by TGF-β. These effects are mediated by both classic and non-classic signaling pathways. Our results indicate that SFN has potent anti-fibrotic and anti-inflammatory effects in HTFs and is a potential candidate for subconjunctival fibrosis therapy.

Insights into the function of cytoglobin

Since its discovery in 2001, the function of cytoglobin has remained elusive. Through extensive in vitro and in vivo research, a range of potential physiological and pathological mechanisms has emerged for this multifunctional member of the hemoglobin family. Currently, over 200 research publications have examined different aspects of cytoglobin structure, redox chemistry and potential roles in cell signalling pathways. This research is wide ranging, but common themes have emerged throughout the research. This review examines the current structural, biochemical and in vivo knowledge of cytoglobin published over the past two decades. Radical scavenging, nitric oxide homeostasis, lipid binding and oxidation and the role of an intramolecular disulfide bond on the redox chemistry are examined, together with aspects and roles for Cygb in cancer progression and liver fibrosis.

Effectiveness of conjunctival bleb scarring by knock-down of heat shock protein 47 in rat model

AIM

To evaluate the effectiveness of knock-down of heat shock protein 47 (HSP47) on conjunctival bleb scarring in a rat model and its possible mechanism.

METHODS

Male Sprague-Dawley rats were used for glaucoma filtration surgery (GFS) and were treated with either phosphate buffered solution, shControl, mitomycin C, or sh-HSP47 using a microsyringe immediately after GFS. The morphology of filtering blebs was observed postoperatively. The levels of HSP47 were analyzed at 2, 5, 8, and 11d after GFS via real-time quantitative polymerase chain reaction (PCR) and Western blot. The silencing effect of HSP47, the expression of collagen I and III, and the potential signaling pathways of HSP47 during scarification were explored 11d post GFS. The protein levels of transforming growth factor-β1 (TGF-β1), phospho-Smad2 (pSmad2), phospho-Smad3 (p-Smad3), and phospho-p38 (p-p38) were also analyzed using Western blot.

RESULTS

Sh-HSP47 treatment significantly prolonged the functional filtration bleb retention. The levels of HSP47 were increased significantly at 5, 8, and 11d postoperatively compared to the control group (P<0.05, P<0.01, and P<0.001). The levels of HSP47 protein at day 11 postoperatively were significantly down-regulated after HSP47 silencing using sh-HSP47 adenovirus transfection (P<0.01). Expression levels of collagen I and III within the blebs were significantly reduced in the absence of HSP47 (P<0.01). Moreover, the protein levels of TGF-β1, p-Smad2/3, and p-p38 were dramatically inhibited after treatment with sh-HSP47 (P<0.01).

CONCLUSION

The inhibitory effects of HSP47 knock-down on scarring after GFS have the potential to be an efficacious therapeutic option for the treatment of conjunctival bleb scarring.

Circ_0080940 Regulates miR-139-5p/CTGF Pathway to Promote the Proliferation, Migration, Extracellular Matrix Deposition of Human Tenon's Capsule Fibroblasts

PURPOSE

Circular RNA (circRNA) has been identified as an important regulator for glaucoma progression. Our study aims to reveal the circ_0080940 roles in glaucoma progression.

METHODS

Transforming growth factor β1 (TGF-β1) was used to treat human Tenon's capsule fibroblasts (HTFs) to mimic glaucoma cell models. Cell function was determined by cell counting kit 8 assay, EdU assay and wound healing assay. Protein levels were determined by western blot analysis. Quantitative real-time PCR was used to measure RNA expression. Dual-luciferase reporter assay was performed to evaluate RNA interaction.

RESULTS

Our data confirmed that TGF-β1 induced HTFs proliferation, migration and extracellular matrix (ECM) deposition. Circ_0080940 was highly expressed in glaucoma patients, and its knockdown inhibited TGF-β1-induced proliferation, migration and ECM deposition in HTFs. Circ_0080940 sponged miR-139-5p, and anti-miR-139-5p revoked the effect of si-circ_0080940 on the biological functions of TGF-β1-induced HTFs. CTGF was targeted by miR-139-5p, and overexpressed CTGF overturned the inhibition effect of miR-139-5p on the biological functions of TGF-β1-induced HTFs. Furthermore, CTGF expression could be positively regulated by circ_0080940.

CONCLUSION

To sum up, we confirmed that circ_0080940 contributed to glaucoma progression by miR-139-5p/CTGF axis.

High Levels of Heat Shock Protein 47 in the Aqueous Humor of Patients with Acute Primary Angle Closure

INTRODUCTION

Acute primary angle closure (APAC) is often characterized by acute elevation of intraocular pressure accompanied by severe ocular and systemic symptoms. Excessive collagen accumulation, which can be caused by upregulated heat shock protein 47 (HSP47) expression, can produce scarring in rat conjunctival blebs. Meanwhile, the presence of HSP47 in human aqueous humor and its levels are yet to be determined.

METHODS

We examined 32 consecutive patients with APAC and 16 age-matched participants without APAC scheduled for cataract surgery who were enrolled as a control group. Aqueous humor samples were collected from all subjects at the time of surgery and compared between the subjects with and without APAC.

RESULTS

The levels of HSP47 in the aqueous humor of patients with APAC (1,210.4 ± 450.2 pg/mL) were found to be significantly increased (p = 0.001) compared with those in the control group (863.4 ± 240.0 pg/mL). Notably, the levels of HSP47 negatively correlated with the age of patients with APAC (p = 0.023).

CONCLUSION

HSP47 was upregulated in the aqueous humor of patients with APAC and may play a role in scarring after trabeculectomy for APAC.

Role of cytoglobin, a novel radical scavenger, in stellate cell activation and hepatic fibrosis

Cytoglobin (Cygb), a stellate cell-specific globin, has recently drawn attention due to its association with liver fibrosis. In the livers of both humans and rodents, Cygb is expressed only in stellate cells and can be utilized as a marker to distinguish stellate cells from hepatic fibroblast-derived myofibroblasts. Loss of Cygb accelerates liver fibrosis and cancer development in mouse models of chronic liver injury including diethylnitrosamine-induced hepatocellular carcinoma, bile duct ligation-induced cholestasis, thioacetamide-induced hepatic fibrosis, and choline-deficient L-amino acid-defined diet-induced non-alcoholic steatohepatitis. This review focuses on the history of research into the role of reactive oxygen species and nitrogen species in liver fibrosis and discusses the current perception of Cygb as a novel radical scavenger with an emphasis on its role in hepatic stellate cell activation and fibrosis.