Proliferation Of Human Tenon's Fibroblasts Research Articles

Zinc oxide nanoparticle-triggered oxidative stress and autophagy activation in human tenon fibroblasts

Glaucoma is a leading cause of irreversible blindness worldwide due to elevated intraocular pressure, and filtering surgery can efficiently control intraocular pressure of glaucoma patients. However, failure of filtering surgery commonly results from scarring formation at the surgical site, in which fibroblast proliferation plays an essential role in the scarring process. Our previous study has demonstrated that zinc oxide (ZnO) nanoparticles could efficiently inhibit human tenon fibroblasts (HTFs) proliferation. The present study aimed to explore the underlying mechanism involved in oxidative stress and autophagy signaling in zinc oxide (ZnO) nanoparticles-induced inhibition of HTFs proliferation. In this study, we investigated the effect of ZnO nanoparticles on HTFs proliferation, mitochondrial function, ATP production and nuclear morphology. Moreover, we also explored the interactions between ZnO nanoparticles and HTFs, investigated the influence of ZnO nanoparticles on the autophagosome formation, the expression of autophagy-related 5 (Atg5), Atg12 and Becn1 (Beclin 1), and the level of light chain 3 (LC3). The results suggested that ZnO nanoparticles can efficiently inhibit HTFs proliferation, disrupt the mitochondrial function, attenuate the adenosine triphosphate (ATP) generation, and damage the nuclear morphology of HTFs. Exposure of HTFs to ZnO nanoparticles can also induce the shifted peak, elevate the expression of Atg5, Atg12 and Becn1, enhance the autophagosome formation, and promote the LC3 expression, and thus activate autophagy signaling. Overall, ZnO nanoparticles can apparently trigger oxidative stress and activate autophagy signaling in HTFs, and thus inhibit HTFs proliferation and mediate HTFs apoptosis.

Zinc oxide nanoparticles ameliorate collagen lattice contraction in human tenon fibroblasts

Glaucoma is a major cause of irreversible blindness in the world and filtering surgery is commonly carried out to control intraocular pressure. Failure of filtering surgery is usually due to postoperative scarring, and fibroblast proliferation, collagen production and subconjunctival fibrosis play a prominent role in obstructing aqueous humor from the anterior chamber to the subconjunctival space. Zinc oxide (ZnO) nanoparticles have been widely applied in biomedical fields. However, the influence of ZnO nanoparticles on human tenon fibroblasts (HTFs) is still unclear. In the present study, we first explored the effects of various concentrations of ZnO nanoparticles on HTFs proliferation, reactive oxygen species (ROS) generation, cell cycle arrest, and apoptosis. Further, we determined the changes of transforming growth factor-β (TGF-β1), fibronectin (FN) extra domain A (ED-A), and procollagen I carboxyterminal propeptide (PICP) at mRNA and protein levels, explored the effect of ZnO nanoparticles on the collagen lattice contraction in HTFs. The results indicated that ZnO nanoparticles can efficiently inhibit HTFs proliferation, elevate ROS production level, and induce cell cycle arrest at G2/M phase, leading to HTFs apoptosis. ZnO nanoparticles can also decrease the expressions of TGF-β1, ED-A, and PICP at mRNA and protein levels; significantly prevent fibroblast-mediated collagen lattice contraction. Taken together, ZnO nanoparticles can efficiently ameliorate collagen lattice contraction in HTFs, and may be a promising antifibrotic agent in glaucoma filtration surgery. Our findings provide a new insight on anti-scar formation after glaucoma filtration surgery by using ZnO nanoparticles.

Low density lipoprotein - rosiglitazone - chitosan-calcium alginate/nanoparticles inhibition of human tenon's fibroblasts activation and proliferation.

Anti-fibrotic therapeutic methods with safety and efficiency after glaucoma filtration surgery (GFS) are desirable. In our previous study, by using Human Tenon's Fibroblasts (HTFs) as a model, we proved the expression of peroxisome proliferator activates receptor-γ (PPAR-γ) in HTFs; in addition, rosiglitazone (RSG), an agonist of PPAR-γ, can inhibit transforming growth factorsβ1 (TGF-β1)-induced reactivation of HTFs, thus to inhibit specifically scarring after GFS through intervening TGF-β/Smads signal pathway. However, a better drug delivery way of RSG, to prolong the duration of its function, and to reduce the toxicity of RSG to ocular tissue still remains challenges. Low density lipoprotein receptor (LDLr) is strongly expressed in hyper-proliferation HTFs after GFS. Therefore, we structured targeting LDL-RSG complexes and channel them into HTFs through LDL-LDLr pathway in order to promote anti-proliferation of HTFs and reduce the toxicity to ocular tissue. Meanwhile, in order to improve the release properties of LDL-RSG complexes, we structured slow release system of LDL-RSG/chitosan-calcium alginate - nanoparticles (CSNP), which effectively inhibited TGF-β1-induced HTFs proliferation, synthesis of extracellular matrix and activation of TGF-β1/SMAD pathway. These data suggested that LDL-RSG/CSNP can be a new anti-fibrotic therapeutic method on scarring after GFS and also a novelty administration of RSG.

Suppression of Human Tenon Fibroblast Cell Proliferation by Lentivirus-Mediated VEGF Small Hairpin RNA.

Purpose. The functions of vascular endothelial growth factor (VEGF) in scar formation after trabeculectomy were investigated in a human Tenon fibroblast cell line from glaucoma patients using lentivirus-mediated VEGF shRNA. Methods. Human Tenon fibroblast (HTF) cells were isolated from scar tissue of glaucoma patients during secondary surgery. Lentivirus-VEGF-shRNA was constructed and transfected into HTF cells. Subsequently, VEGF mRNA and protein expression were analyzed using quantitative RT-PCR and western blotting, respectively, and the effects of VEGF knockdown were analyzed. The inhibition of HTF proliferation was monitored according to total cell numbers using ScanArray. Results. Both mRNA and protein levels of VEGF were reduced by lentivirus-mediated VEGF-shRNA, and proliferation of HTF cells was inhibited. Conclusions. Primary cultures of human Tenon fibroblast (HTF) were established, and proliferation was decreased following inhibition of VEGF. VEGF may be a suitable therapeutic target for reducing scar tissue formation in glaucoma patients after filtration surgery.

Rho kinase inhibitor AMA0526 improves surgical outcome in a rabbit model of glaucoma filtration surgery.

First, to elucidate the effect of Rho kinase inhibitor, AMA0526, on Human Tenon Fibroblast (HTF) proliferation and transdifferentiation to myofibroblasts. Second, the effects of ROCK inhibition on the wound healing process and surgical outcome were investigated in a rabbit model of glaucoma filtration surgery. After exposure of HTF to AMA0526 (0.1-25 μM), a water-soluble tetrazolium salt-1 assay and caspase 3/7 activity assay were used to assess its effect on cell proliferation and to elucidate any toxic effects, respectively. Immunohistochemistry of α-smooth muscle actin expression was used to investigate fibroblast-to-myofibroblast differentiation induced by transforming growth factor-beta 1 (TGF-β1) in the presence or absence of the ROCK inhibitor. The effect of topical treatment was studied in a rabbit model of glaucoma filtration surgery. Treatment outcome was studied by performing intraocular pressure (IOP) measurements and clinical investigation of the bleb area and survival. Immunohistological analysis for inflammation (CD45), angiogenesis (CD31), and collagen I was performed at day 8, 14, and 30 after surgery (n=5/time point). Separate control groups treated with vehicle were used as control. In vitro results showed that AMA0526 dose dependently inhibited proliferation of HTF (P<0.05) without the induction of caspase 3/7 activity. Incubation of HTF with the AMA0526 inhibited TGF-β1 induced fibroblast-to-myofibroblast differentiation. In the rabbit model, topical treatment significantly improved surgical outcome. Compared to vehicle-treated eyes, AMA0526 resulted in increased bleb area (P<0.0001) and prolonged survival (P=0.0025). IOP remained significantly lower throughout the course of the experiment in the AMA0526 group (P<0.0001). Histological evaluation revealed that blebs treated with the ROCK inhibitor were characterized by reduced inflammation, angiogenesis, and collagen deposition at the site of filtration surgery (P<0.05). AMA0526 had profound effects on HTF proliferation and myofibroblast transition and improved glaucoma filtration surgery outcome by interfering at different levels of the wound healing process. Therefore, these data indicate that ROCK inhibitors may be considered as more physiological agents which specifically target the wound healing process to improve the outcome of glaucoma surgery.

Rho Kinase Inhibitor AMA0526 improves surgical outcome in a rabbit model of glaucoma filtration surgery

AbstractPurpose To elucidate the effect of the ROCK inhibitor AMA0526 on the wound healing process and surgical outcome of glaucoma filtration surgery.Methods The in vitro effect of ROCK inhibitor AMA0526 on human brain microvascular endothelial cells (HBMEC) and human Tenon fibroblasts (HTF) was determined using a proliferation assay. Secondly the in vivo effect of topical AMA0526 0.3% TID was investigated in a rabbit model of glaucoma filtration surgery (n=5/time point). Treatment outcome was studied by clinical investigation of the bleb area as well as immunohistological analyses for inflammation (CD45), angiogenesis (CD31) and collagen deposition at day 8, 14 and 30 after surgery. Contralateral eyes were used as control and were treated with vehicle.Results A dose‐dependent reduction of HBMEC and HTF proliferation was measured after incubation with AMA0526. Incubation with the highest concentration of AMA0526 reduced proliferation of HBMEC and HTF to 22 and 35%. In the surgery model, AMA0526 significantly improved bleb area and survival compared to vehicle treated eyes. Immunohistological analyses showed significant reduction of inflammation, angiogenesis and collagen deposition after treatment with the ROCK inhibitor. Compared to vehicle, inflammation was decreased by 33% at 8 days and angiogenesis by 52% on day 8 and by 29% at 14 days. Collagen deposition was significantly reduced by 11 and 42% on day 14 and 30.Conclusion This study shows that AMA0526 is able to inhibit proliferation of microvascular endothelial cells and Tenon fibroblasts in vitro, and to improve glaucoma surgery outcome in rabbits. In addition to improved bleb area, AMA0526 led to decreased inflammation, angiogenesis and fibrosis.

Effects of ranibizumab on the extracellular matrix production by human Tenon's fibroblast

Anti-Vascular Endothelial Growth Factors (Anti-VEGF) agents have received recent interest as potential anti-fibrotic agents for their concurrent use with trabeculectomy. Preliminary cohort studies have revealed improved bleb morphology following trabeculectomy augmented with ranibizumab. The effects of this humanized monoclonal antibody on human Tenon's fibroblast (HTF), the key player of post trabeculectomy scar formation, are not fully understood. This study was conducted to understand the effects of ranibizumab on extracellular matrix production by HTF. The effect of ranibizumab on HTF proliferation and cell viability was determined using MTT assay (3-(4,5-dimethylthiazone-2-yl)-2,5-diphenyl tetrazolium). Ranibizumab at concentrations ranging from 0.01 to 0.5 mg/mL were administered for 24, 48 and 72 h in serum and serum free conditions. Supernatants and cell lysates from samples were assessed for collagen type 1 alpha 1 and fibronectin mRNA and protein level using quantitative real time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). After 48-h, ranibizumab at 0.5 mg/mL, significantly induced cell death under serum-free culture conditions (p < 0.05). Ranibizumab caused significant reduction of collagen type 1 alpha 1 (COL1A1) mRNA, but not for fibronectin (FN). Meanwhile, COL1A1 and FN protein levels were found upregulated in treated monolayers compared to control monolayers. Ranibizumab at 0.5 mg/mL significantly reduced cell viability in cultured HTF. From this study, we found that single application of ranibizumab is inadequate to induce the anti-fibrotic effects on HTF, suggesting the importance of adjunctive therapy. Further studies are underway to understand mechanism of actions of ranibizumab on HTF.

A TGF-β receptor 1 inhibitor for prevention of proliferative vitreoretinopathy

This study evaluates the use of the TGF-β receptor 1 inhibitor LY-364947 (LY) to prevent proliferative vitreoretinopathy (PVR). For the in vitro experiments Human Tenon's Fibroblasts (HTFs) and retinal pigment epithelial (RPE) cells were treated with different concentrations of LY to determine HTF proliferation and RPE transdifferentiation. For in vivo testing 30 rabbits underwent a PVR trauma model. The animals received different concentrations of intravitreally injected LY, with or without vitrectomy. LY treatment reduced HTF proliferation and RPE transdifferentiation in vitro. In vivo intravitreal injection of LY prevented PVR development significantly. This positive effect was also present when LY injection was combined with vitrectomy. Intravitreal injection of LY prevented tractional retinal detachment in 14 out of 15 animals. In conclusion, treatment with the TGF-β receptor 1 inhibitor LY reduces HTF proliferation and RPE transdifferentiation in vitro and prevents proliferative vitreoretinopathy and subsequent tractional retinal detachment in vivo.

MicroRNA-216b/Beclin 1 axis regulates autophagy and apoptosis in human Tenon's capsule fibroblasts upon hydroxycamptothecin exposure

Proliferation and fibrosis of human Tenon's fibroblasts (HTFs) have significantly challenged the outcome of glaucoma filtration surgery. Hydroxycamptothecin (HCPT) is considered as a potential chemical to overcome this issue as it was previously shown that HCPT inhibited cell proliferation and induced apoptosis in fibroblasts. Here, we further dissected the molecular pathway, through which the HCPT inhibit the proliferation of HTFs. We showed that HCPT induced significant autophagy as well as apoptosis, two self-destructive processes, and down-regulated the expression of miR-216b in HTFs. Overexpression of miR-216b in HTFs suppressed the autophagy and apoptosis induced by HCPT, whereas silence of miR-216b led to effects that were similar to those caused by the treatment with HCPT. Further, we showed that miR-216b could directly target a specific fragment in the 3′ untranslated region of Beclin 1 as demonstrated by luciferase assay, and consequently decreased the expression of Beclin 1. Consistently, knocking down Beclin 1 significantly decreased HCPT-triggered autophagy and apoptosis, and increased the viability of HTFs treated with HCPT, thus implicating that Beclin 1 functions as a pro-apoptotic molecule in this circumstance. Altogether, we concluded that miR-216b regulated both autophagy and apoptosis by modulating Beclin 1 in HTFs treated with HCPT. We also demonstrated that HCPT-induced autophagy is one of the agent's anti-proliferative effects.

Effect of paclitaxel on proliferation of human Tenon fibroblast and its probably mechanism

Background The excessive growth of human Tenon fibroblasts (HTFs) is a primary cause of failure of anti-glaucomatous filtering surgery.To seek a drug of anti-fibrosis is of an important significance for improving the successful rate of anti-glaucomatous filtration surgery.Objective The goal of this study was to investigate the effect of paclitaxel on proliferation of HTFs in vitro.Methods Human Tenon tissue was obtained during the anti-glaucomatous filtering surgery.HTFs were cultivated using explant method and 3-6 generations of cells were used in the experiment.The cells were identified by immunochemistry using keratin,vimentin,fibronectin and S-100.Different concentrations (0,1 ×10-s,1 × 10-7,1 × 10-6 mol/L) of paclitaxel were added into the medium,and then the cell indexes (CI) in the various groups were detected by real-time cell electronic sensing (RT-CES) 24 hours after affection of paclitaxel.Apoptosis of the cells was examined using DAPI staining,and the proportion of the cells in different cycles were assayed by flow cytorneter 12 hours after addition of paclitaxel.The expressions of matrix metalloproteinase-1 (MMP-1) protein and mRNA were detected by ELISA and real-time PCR,respectively.Results The cells migrated from the cultivated tissue within 7 days with the fibrocyte-like shape.The cells showed the positive response for vimentin and absent response for keratin,fibronectin and S-100.The CI values were 1.093 ±0.191,0.665 ± 0.093 and 0.473 ± 0.117 in the 1 × 10-8,1 × 10-7 and 1 × 10-6 mol/L paclitaxel groups,showing significant rise in comparison with the 1.514 ±0.283 of the 0 mol/L paclitaxel group (all at P =0.000).The cell nuclei were normal in the 0 mol/L paclitaxel group,however,blue-fluorescent particles and apoptotic bodied were found in the cell nuclei after affection of paclitaxel.The proportion of G2/M phase of cells were (9.20±0.80) ％,(12.37±0.45)％ and (13.80±0.35)％ in the 1×10-8 mol/L,1×10-7 mol/L and 1×10-6 mol/L paclitaxel groups,which were higher than the (7.17±0.50) ％ in the 0 mol/L paclitaxel group (P=0.005,0.000,0.000).In addition,the relative expressing level of M MP-1 mRNA (MMP-1 mRNA/GAPDH mRNA) and the expression level of MMP-1 protein in the HTFs were significantly lower in the 1 ×10-8 mol/L,1 × 10-7 mol/L and 1 × 10-6 mol/L paclitaxel groups than those in the 0 mol/L group (all at P＜0.05).Conclusions Paclitaxel at the concentrations of 1 × 10-8 mol/L-1 × 10-6 mol/L inhibits the proliferation of HTFs in vitro by arresting the cellular mitosis and inducing cell apoptosis.These effects probably associated with down-regulation of MMP-1 expression in the HTFs. Key words: Paclitaxe/pharmacology ; Glaucoma/surgery; Tenon capsule/ cytology; Fibroblast/cytology; Matrix metalloproteinase-1

Effects of Pirfenidone on Proliferation, Migration, and Collagen Contraction of Human Tenon’s Fibroblasts In Vitro

To investigate the effect of pirfenidone, a novel antifibrotic agent, on proliferation, migration, and collagen contraction of human Tenon's fibroblasts (HTFs). After treatment of HTFs with pirfenidone, cell proliferation was measured by MTT assay. Cell migration was investigated by scratch assay. Contractility was evaluated in fibroblast-populated collagen gels. Cell viability was determined by trypan blue exclusion assay. The expression of TGF-beta1, -beta2, and -beta3 was estimated with RT-PCR, Western blot, and immunofluorescence analyses. Pirfenidone induced significant dose-dependent inhibition of HTF proliferation and migration and collagen contraction. After treatment with different concentrations of pirfenidone (0.15, 0.3, and 1 mg/mL) for 24 and 72 hours, cell viability was not different in the treatment and control groups. After 24 hours of treatment with pirfenidone, HTFs showed dose-dependent decreases in mRNA and protein levels of TGF-beta1, -beta2, and -beta3. These findings indicate that pirfenidone inhibits proliferation, migration, and collagen contraction of HTFs at nontoxic concentrations. A decrease in autocrine TGF-beta signaling may have a role in the effects of pirfenidone.

P38 Inhibitors Prevent TGF-β–Induced Myofibroblast Transdifferentiation in Human Tenon Fibroblasts

The role of mitogen-activated protein kinase (MAPK) pathways in TGF-beta-induced myofibroblast transdifferentiation of human tenon fibroblasts (HTFs) was investigated to identify potential pharmacologic targets for the inhibition of scarring after glaucoma surgery. TGF-beta-dependent activation of Smad2, p38, and Erk-1/2 was examined by Western blot analysis. TGF-beta-induced mRNA expression of collagen Ialpha1, fibronectin, and the myofibroblast transdifferentiation marker alpha smooth muscle actin (alpha-SMA) was analyzed by real-time RT-PCR. alpha-SMA protein expression and subcellular distribution were determined by Western blot analysis and immunofluorescence cytochemistry. Fibroblast contractility was assessed in three-dimensional collagen gel contraction assays, stress fiber assembly with rhodamine-phalloidin stains, and confocal microscopy. Cell proliferation was measured with an MTT assay. Specific pharmacologic kinase inhibitors were used to characterize the involvement of MAPK-dependent pathways. TGF-beta stimulation of HTF induced a rapid and transient activation of Smad2 and Erk, whereas p38 activation was biphasic and sustained. After 24 hours of TGF-beta stimulation, increased levels of collagen Ialpha1, fibronectin, and alpha-SMA transcripts were detected. After 3 days of stimulation, HTF displayed increased alpha-SMA protein levels, enhanced contractility, and assembly of actin stress fibers. TGF-beta also induced HTF proliferation. Specific p38 inhibitors prevented all these aspects of TGF-beta-induced myofibroblastic transdifferentiation. Pharmacologic inhibition of p38 abrogates TGF-beta-induced myofibroblast transdifferentiation, reduces extracellular matrix protein expression and HTF proliferation, and may therefore serve to inhibit scarring after glaucoma surgery.

Alkylphosphocholines: a new therapeutic option in glaucoma filtration surgery.

To investigate the effect of alkylphosphocholines (APCs) on human Tenon fibroblast (HTF) proliferation, migration, and cell-mediated collagen gel contraction. HTFs were isolated from tissue samples of three patients obtained during surgery and cultured in DMEM and 10% fetal calf serum (FCS). HTFs (passage 3-6) were treated with one APC in different concentrations spanning the 50% inhibitory concentration (IC(50)), as determined previously. Inhibition of cell proliferation was assessed by the tetrazolium dye reduction assay. Migration was determined in chemoattractant chambers with fibronectin-coated polycarbonated membranes. For inhibition of contraction, three-dimensional collagen gels were seeded with HTFs, and the gel size was measured. Cell viability was determined by the trypan blue exclusion assay. For analysis of the mechanism of action, protein kinase C (PKC) activity was measured. The IC(50) varied between 7.0 and 10.5 microM for all APCs tested. At this concentration, all four APCs inhibited HTF migration and cell-mediated collagen gel contraction in the presence of serum. The inhibitory effects on HTF proliferation, migration, and contraction were observed at nontoxic concentrations. PKC activity was reduced to 50% of control level at the IC(50) of all APCs applied. APCs are effective inhibitors of HTF proliferation, migration, and cell-mediated contraction of collagen gels at nontoxic concentrations. Their mechanism of action seems to involve the inhibition of the PKC pathway.

Antiproliferative effect of mycophenolate mofetil on cultured human Tenon fibroblasts.

Wound healing after glaucoma filtering surgery is often complicated by exaggerated scarring of the subconjunctival Tenon's layer. Therefore, antiproliferatives are commonly employed. The immunosuppressive drug mycophenolate mofetil (MMF) is used to prevent graft rejection after kidney or liver transplantation. The effect is mediated by inhibition of lymphocyte proliferation. In this study we investigated the effect of MMF on human Tenon fibroblast proliferation in cell culture. Human Tenon fibroblasts (HTF) were cultivated with 10% fetal calf serum. Cells were incubated with MMF concentrations of 0.1 microM to 3000 microM for up to 20 days. In a second set of experiments HTF were incubated for 10 min only in MMF solutions. Cell counts were performed to evaluate the proliferation rate. The proliferation was also assessed by Ki67 staining. Morphological changes were documented by vimentin staining. Growth inhibition of HTF by MMF was concentration dependent. IC(50) was 0.85+/-0.05 microM for 6 days of incubation. Brief exposure to MMF leads to a reversible growth arrest for up to 14 days with concentrations of 1000 microM or higher. Ki67 staining confirmed the concentration dependent proliferation rate. MMF has a concentration-dependent antiproliferative effect on HTF without any detected cytotoxicity in the applied concentration range. Brief incubation also leads to a growth arrest; therefore, intraoperative MMF application might prevent exaggerated scarring after glaucoma filtering surgery.