Involvement of METTL3/m6Adenosine and TGFß/Smad3 signaling on Tenon's fibroblasts and in a rabbit model of glaucoma surgery.

Glaucoma filtration surgery (GFS) is a classic operation for the treatment of glaucoma, which is the second leading cause of blindness, and scar formation caused by excessive human Tenon's capsule fibroblasts (HTFs) activation is responsible for surgery failure. However, the mechanism underlying excessive HTFs activation is largely unknown. Studies have revealed that N6-methyladenosine (m6A), which is one of the most common posttranscriptional modifications, plays an important role in multiple types of cellular processes. First, we isolated and identified primary HTFs and found that transforming growth factor-ß1 (TGF-ß1) enhanced cell viability and promoted cell proliferation and extracellular matrix (ECM) deposition in HTFs. We subsequently found that TGF-ß1 elevated the quantity of m6A and promoted the expression of m6A "writers", in the process from DNA to RNA, adenylate was methylated at the sixth N position by methylases methyltransferase-like 3 (METTL3). Furthermore, we demonstrated that METTL3 repression inhibited the promotion of cell viability, proliferation and ECM deposition in HTFs treated with TGF-ß1. We then illustrated that increased METTL3 played a role by promoting Smad3 in TGF-ß1-induced HTFs. We subsequently demonstrated that the METTL3/Smad3 regulatory axis was aberrantly expressed in the rabbit model of GFS. Thus, our study reveals that METTL3 indeed plays a role in modulating Smad3 in TGF-ß1-induced HTFs and further provides novel theoretical strategies based on METTL3 for the inhibition of scar formation after GFS.

Effects of Qingguang'an containing serum on the expression levels of autophagy-related genes in human Tenon's fibroblasts induced by transforming growth factor beta 1.

OBJECTIVE: To explore the effects of Qingguang'an () containing serum on the expression levels of autophagy related genes in the transforming growth factor beta 1 (TGF-ß1)-activated human Tenon's fibroblasts (HTFs). METHODS: (a) Primary HTFs were stimulated by TGF-ß1 and underwent immunohistochemistry, which established a cell model after Glaucoma filtration surgery (GFS). (b) The cell models were divided into 4 group: normal group (normal cells), model group (+TGF-ß1),treatment group (+TGF-ß1+ medicated serum), and positive control group (TGF-ß1+ rapamycin). Then, Qingguang'an medicated serum with optimum concentration was added to the corresponding group. The autophagy positive cells were identified by the Cyto-ID autophagy detection kits under fluorescent microscope and Cytation 5 multifunctional instrument for cell imaging. And the mean fluorescence intensity of autophagy positive cells was determined by flow cytometry. The expression levels of autophagy related genes － Beclin-1, autophagy related gene 5 (ATG-5), and microtubule-associated protein 1 light chain 3 (LC-3Ⅱ were detected by quantitative reverse transcription-polymerase chain reaction and Western blot analysis. RESULTS: Compared with the normal group and the model group, the relative mRNA expression levels of autophagy-related genes (Beclin-1, ATG-5 and LC-3Ⅱ in the experimental group were notably increased (P < 0.05, P < 0.01), and with the extension of treatment time, it had an increasing trend (48 h was more obvious), which showed a certain time dependency; the protein expression levels of autophagy-related genes (Beclin-1, ATG-5, and LC-3Ⅱ were significantly increased in the experimental group (P < 0.05, P < 0.01). With the prolongation of treatment time, there was an increasing trend (48 h was relatively obvious), and it revealed a certain time dependency. CONCLUSION: The Qingguang'an medicated serum could up-regulate autophagy related genes (Beclin1, ATG5, and LC3Ⅱ in the TGF-ß1-activated HTFs.

Differential Effects of TGF-ß2 on the Low-Density Lipoprotein Receptor Expression in Three Types of Human Subconjunctival Fibroblasts.

Purpose: To investigate whether TGF-ß2 had a different effect on the expression levels of low-density lipoprotein receptor (LDLr) in the subconjunctival fibroblasts from glaucoma patients who underwent a reoperation (RGSFs) compared with those from glaucoma patients who underwent first filtering surgery (GSFs) and control patients with cataracts (HSFs). Methods: Human subconjunctival fibroblasts were obtained from the three groups of patients. Different concentrations of TGF-ß2 were added to the fibroblasts for 1, 3, and 5 days. The proliferation of the fibroblasts was determined by CCK-8 assays. Real-time PCR and western blotting were performed to analyze the mRNA and protein levels of LDLr. The uptake of DiI-labeled LDL was determined by confocal microscopy. Results: The results revealed that under TGF-ß2 exposure, fibroblast proliferation was positively correlated with LDLr expression (all p < .001). The LDLr mRNA and protein levels were affected by TGF-ß2 in a concentration-dependent and time-dependent manner in the RGSFs, GSFs and HSFs. The maximal expression of LDLr after TGF-ß2 stimulation was consistent with the peak uptake of DiI-LDL, which was obviously highest in the RGSFs, followed by the GSFs, and then the HSFs (all p < .05). All 3 groups took up DiI-LDL in a similar time-dependent manner, with maximal uptake at 6 h following DiI-LDL incubation (all p < .05). In addition, there were significant differences in the LDLr protein levels in the subconjunctival tissues isolated from the glaucoma patients during reoperation, the glaucoma patients during first filtering surgery and the control patients at day 3 (p < .05). The highest protein expression of LDLr was observed in the RG group. Conclusion: These data suggested that the RGSFs had the highest LDLr expression and the highest peak uptake of LDL among three groups. The LDLr-drug-LDL delivery system could potentially be used for targeted delivery of antimetabolite agents in anti-scarring therapy for glaucoma patients after filtering surgery.

Natural Plant Extract Berbamine Is a Potent Inhibitor of Cell Growth and Survival of Human Tenon's Fibroblasts.

INTRODUCTION: Post-trabeculectomy scarring due to excessive proliferation of human Tenon's fibroblasts (HTFs) often led to operation failure. Developing a new anti-fibrosis drug with high efficacy to inhibit HTF cell growth will greatly improve the effectiveness of trabeculectomy. OBJECTIVE: This study aims to investigate the effect of berbamine (BBM) treatment on the cell growth and survival of HTFs. METHODS: Cultured human fetal Tenon's fibroblasts (HFTFs) were treated with or without different concentrations of BBM. Cell morphology was observed with a phase contrast microscope. A CCK-8 method and Ki67 immunofluorescence were used to determine cell viability and cell proliferation. A scratch test was used to study cell migration. Flow cytometry and TUNEL staining were performed to detect cell apoptosis. The expression of BAX/BCL-2, ERK, and AKT/mTOR pathway components was determined by Western blotting. RESULTS: BBM treatment disrupted HFTF normal morphology and inhibited its cell growth in a dose-dependent manner. Ki67 immunofluorescence and scratch assay showed BBM suppressed HFTF cell proliferation and migration. Importantly, BBM dose-dependently increased the BAX/BCL-2 ratio and induced apoptosis in HFTF cells. Western blotting showed BBM significantly inhibited the ERK and AKT/mTOR pathway, and PTEN inhibition ameliorated the inhibitory effect of BBM on cell viability and survival in HFTFs. CONCLUSIONS: BBM potently inhibits the cell growth and survival of HTFs through AKT/mTOR and has the potential to serve as an anti-fibrosis drug after trabeculectomy.

Antifibrotic Effects of Sakuraso-Saponin in Primary Cultured Pterygium Fibroblasts in Comparison With Mitomycin C.

Purpose: To investigate the antifibrotic effects of sakuraso-saponin on a primary culture of human pterygium fibroblasts (HPFs) and normal human Tenon fibroblasts (HTFs) as compared to the effects of mitomycin C (MMC). Methods: Samples of HPFs and HTFs were acquired during primary pterygium surgery. Cell toxicity, cell migration, and expression of α-smooth muscle actin (α-SMA) and transforming growth factor-ß (TGF-ß) were evaluated in HPFs and HTFs after treatment with sakuraso-saponin and MMC. To determine the possible mechanisms underlying the antifibrotic effects of sakuraso-saponin, the expression of phosphorylated Smad2/3 was evaluated after treatment with sakuraso-saponin and MMC. Results: MMC (≥200 µg/mL) significantly reduced cell viability in both HPFs and HTFs, whereas sakuraso-saponin (1.0 µg/mL) decreased cell viability in HPFs only. Both sakuraso-saponin (1.0 µg/mL) and MMC (200 µg/mL) treatment significantly reduced the expression of α-SMA and TGF-ß in HPFs (P < 0.05). It is interesting that the expression of α-SMA and TGF-ß after treatment with sakuraso-saponin was significantly lower than that after treatment with MMC (P < 0.05). The expression of phosphorylated Smad2/3 protein was decreased by sakuraso-saponin and MMC in HPFs. Both sakuraso-saponin and MMC inhibited TGF-ß1-induced cell migration as compared to the control in HPFs. Conclusions: Sakuraso-saponin could be more effective than MMC for the reduction of fibrosis in HPFs. Our results might present the basis for its use as a promising candidate drug for adjuvant therapy to prevent recurrent pterygium after surgery.

Rosiglitazone Treatment Prevents Postoperative Fibrosis in a Rabbit Model of Glaucoma Filtration Surgery.

Purpose: To evaluate the potential antifibrotic effect of rosiglitazone (RSG), a peroxisome proliferator-activated receptor γ (PPARγ)-selective agonist, on subconjunctival fibrosis in a rabbit model of glaucoma filtration surgery (GFS) in vivo, and to investigate the underlying mechanisms in human Tenon's fibroblasts (HTFs) in vitro. Methods: GFS were performed on adult male New Zealand white rabbits with chronic ocular hypertension previously established by injections of 2% methylcellulose into the anterior chamber. Rabbits were treated by RSG, mitomycin C (MMC) or 5-fluorouracil (5-FU) intraoperatively. The morphology of filtering blebs was evaluated by Indiana Bleb Appearance Grading Scale (IBAGS) scoring. Expression of profibrotic genes was determined by quantitative PCR, immunoblot, and/or histochemical analysis. In vitro studies were performed in a transforming growth factor (TGF)-ß1-based cell model of fibrosis. Autophagy was evaluated by the formation of autophagosomes and autolysosomes using fluorescent and transmission electron microscopy and by expression of key mediators in the autophagic pathway. Results: RSG treatment ameliorated a rebound intraocular pressure (IOP) elevation, prolonged the survival of filtering blebs, and attenuated subconjunctival fibrosis in rabbits following trabeculectomy. Pretreatment of HTFs with RSG inhibited TGF-ß1-induced expression of profibrotic genes encoding specificity protein 1, connective tissue growth factor, and α smooth muscle actin. RSG augmented TGF-ß1-induced autophagy in HTFs via a beclin1/VPS34-dependent mechanism. Augmentation of autophagy is associated with inhibition of TGF-ß1-induced profibrotic gene expression by RSG. Conclusions: RSG treatment prevents subconjunctival fibrosis after GFS by inhibition of profibrotic gene expression through a mechanism involved in promoting autophagy in local fibroblasts. RSG represents a novel antifibrotic drug with the potential to improve the success rate of GFS.

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-ß (TGF-ß1), 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-ß1, 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.

The Smad2/3/4 complex binds miR-139 promoter to modulate TGFß-induced proliferation and activation of human Tenon's capsule fibroblasts through the Wnt pathway.

The activation and proliferation of human Tenon's fibroblasts (HTFs) play a vital role in the fibrosis in the pathology of the scar formation after the glaucoma filtration surgery. Transforming growth factor ß1 (TGFß1)/Smads signaling has been reported to promote fibrosis. In our previous study, we revealed that TGFß1-induced orbital fibroblast activation and proliferation through Wnt/ß-catenin signaling. As microRNA (miR)-139 could target several factors in Wnt signaling to modulate fibrosis, here, the effect and mechanism of miR-139 in HTF activation and proliferation were investigated. miR-139 overexpression significantly reversed the TGFß1-induced increase in collagen I and α-smooth muscle actin contents and proliferation in HTFs. CTNNB1 and CTNND1 were direct downstream of miR-139 and can significantly restore the suppressive effect of miR-139 on the activation and proliferation in HTFs under TGFß1 stimulation. Smad2/3/4 complex inhibits the transcription activity of miR-139, most possibly by Smad4 binding to the miR-139 promoter. Taken together, we demonstrated a new mechanism of HTF activation and proliferation from the perspective of miRNA regulation, which may provide new strategies for improving the fibrosis after the glaucoma filtration surgery.

TGF-ß1 Induces Human Tenon's Fibroblasts Fibrosis via miR-200b and Its Suppression of PTEN Signaling.

BACKGROUND: To determine the involvement of MicroRNA-200b (miR-200b) in human Tenon's fibroblasts (HTFs) fibrosis. METHODS: HTFs were treated with 10 ng/ml TGF-ß1 for 24 h. Expression of α-smooth muscle actin (α-SMA), Fibronectin and Collagen1A1 (COL1A1) was assessed by western blot and immunofluorescence. MiR-200b was detected by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR), and its potential target genes were validated by luciferase assay. The effects of miR-200b and PTEN (the target gene) on HTFs fibrogenesis were evaluated using miR-200b mimics or inhibitor transfected HTFs, and confirmed with PTEN-specific small interfering RNA (siRNA) and PTEN inhibitor. RESULTS: TGF-ß1 up-regulated miR-200b and promoted the expression of α-SMA, Fibronectin and COL1A1 in HTFs, and the effects could be strengthened or hampered by adding miR-200b mimics or inhibitor, respectively. Luciferase assay identified PTEN as the target gene of miR-200b, and decreased PTEN level due to up-regulation of miR-200b was found to correlate with intensified expression of α-SMA, Fibronectin and COL1A1. Determination of PTEN's role in fibrosis was carried out by adding PTEN specific siRNA or PTEN inhibitor into HTFs, which led to intensified expression of fibrosis-related proteins. CONCLUSION: TGF-ß1-mediated miR-200b induces HTFs fibrosis through suppressing PTEN signaling pathway.

Nintedanib inhibits TGF-ß-induced myofibroblast transdifferentiation in human Tenon's fibroblasts.

Purpose: This study aimed to investigate the effect of nintedanib on the conversion of human Tenon's fibroblasts (HTFs) into myofibroblasts and reveal the molecular mechanisms involved. Methods: Primary cultured HTFs were incubated with transforming growth factor ß1 (TGF-ß1) alone or combined with nintedanib, and cell proliferation and migration were measured by cell counting kit-8 (CCK8) and the scratch wound assay, respectively. HTF contractility was evaluated with a 3D collagen contraction assay. The mRNA and protein levels of α smooth muscle actin (α-SMA) and Snail and the phosphorylation levels of Smad2/3, p38 mitogen-activated protein kinase (p38MAPK), and extracellular signal-regulated kinase ½ (ERK1/2) were determined by quantitative reverse transcription polymerase chain reaction (RT-PCR), western blot, and immunofluorescence staining. Results: Nintedanib inhibited the proliferation and migration of HTFs in a dose-dependent manner. Furthermore, nintedanib prevented HTF myofibroblast differentiation via downregulation of mRNA and protein expression of α-SMA and Snail. A three-dimensional (3D) collagen gel contraction assay demonstrated that nintedanib effectively inhibits myofibroblast contraction induced by TGF-ß1. Mechanistically, we revealed that nintedanib reduces the TGF-ß1-induced phosphorylation of Smad2/3, p38MAPK, and ERK1/2, suggesting that nintedanib acts through both classic and nonclassic signaling pathways of TGF-ß1 to prevent HTF activation. Conclusions: Our study provides new evidence that nintedanib has potent antifibrotic effects in HTFs and suggests that it may be used as a potential therapeutic agent for subconjunctival fibrosis.

The Antiangiogenesis Effect of Pirfenidone in Wound Healing In Vitro.

Abstracts Purpose: Pirfenidone is mostly used in antifibrotic and anti-inflammatory therapies. We have previously demonstrated that pirfenidone had antifibrotic and anti-inflammatory effects on the wound healing process after glaucoma filtration surgery in vitro and in vivo. Since the wound healing and reactive scarring process simultaneously involves inflammation, fibrosis, and angiogenesis, and angiogenesis plays a more important role in chronic or prolonged wound healing, we tried to explore the antiangiogenesis effect in pirfenidone and its potential multitarget function in regulating excessive scarring. The aim of the present study was to investigate the antiangiogenesis effect of pirfenidone. METHODS: The proliferation of human umbilical vein endothelial cells (HUVECs) and human Tenon's fibroblasts (HTFs) were detected by WST-1 assay. The cell viability of HUVECs was measured by Trypan Blue together with lactate dehydrogenase, Annexin 5 experiment, and Ki-67 immunofluorescence assay. The functions of HUVECs and HTFs were demonstrated using cell migration assay, transwell invasion assay, and tube formation assay. The expression levels of vascular endothelial growth factor-A (VEGF-A), VEGF receptor-2 (VEGFR-2), neuropilin-1(NRP-1), and their downstream signaling proteins p-PI3K, PI3K, p-AKT, AKT, p-mTOR, and mechanistic target of rapamycin (mTOR) were indicated by western blot assay. The secretion of VEGF-A was detected by enzyme-linked immunosorbent assay. RESULTS: Pirfenidone inhibited proliferation, migration, invasion, and tube formation of HUVECs in vitro, and had an equivalent antiangiogenesis effect when compared with Ranibizumab in HUVECs and HTFs. Pirfenidone downregulated VEGF-A/VEGFR-2, VEGF-A/NRP-1, and its downstream signaling pathway protein expression. CONCLUSIONS: Pirfenidone has an antiangiogenesis effect in the wound healing process and may become an ideal multitarget antiscarring agent after glaucoma filtration surgery.

5-Aza-2'-deoxycytidine induces human Tenon's capsule fibroblasts differentiation and fibrosis by up-regulating TGF-ß type I receptor.

The principle reason of high failure rate of glaucoma filtration surgery is the loss of filtration function caused by postoperative scar formation. We investigated the effects of 5-aza-2'-deoxycytidine (5-Aza-dc), a DNA methyltransferases inhibitor, on human Tenon's capsule fibroblasts (HTFs) differentiation and fibrosis and its mechanism of action, especially in relation to transforming growth factor (TGF)-ß1 signaling. TGF-ß1 was used to induce differentiation of cultured HTFs. 5-Aza-dc suppressed DNA methyltransferases (DNMTs) activity 6 h after treatment with a course corresponding to that of TGF-ß1-induced reduction of DNMT activity without affecting cell viability as measured by Cell Counting Kit-8 assay. 5-Aza-dc also reduced DNMT1 and DNMT3a protein expression from 24 to 48 h. HTFs migration evaluated by scratch-wound assay were significantly increased 24 h after 5-Aza-dc treatment, a time course similar to that of TGF-ß1. Treatment with 5-Aza-dc significantly increased the mRNA and protein levels of α-smooth muscle actin (α-SMA), collagen-1A1 (Col1A1), fibronectin (FN) and TGF-ß type I receptor (TGFßRI). Furthermore, the effects of 5-Aza-dc on DNMT activity suppression, cell migration, and fibrosis were all reversed by a TGFßRI inhibitor- SB-431542. Meanwhile, knockdown of DNMT1 upregulated TGFßRI expression and had the same fibrosis-inducing effect in HTFs, which was also inhibited by SB-431542. Thus, the results indicate that DNA hypomethylation induces HTFs differentiation and fibrosis through up-regulation of TGFßRI. DNA methylation status plays an important role in subconjunctival wound healing.

Silibinin Inhibits Platelet-Derived Growth Factor-Driven Cell Proliferation via Downregulation of N-Glycosylation in Human Tenon's Fibroblasts in a Proteasome-Dependent Manner.

The objective of this study was to evaluate the effects of silibinin on cell proliferation in platelet-derived growth factor (PDGF)-treated human Tenon's fibroblasts (HTFs). The effect of silibinin on cell proliferation in PDGF-treated HTFs was determined by examining the expression of proliferating cell nuclear antigen (PCNA) and performing WST-1 assays. Cell cycle progression was evaluated using flow cytometry. The related cyclins and cyclin-dependent kinases (CDKs) were also analyzed using western blot. A modified rat trabeculectomy model was established to evaluate the effect of silibinin on cell proliferation in vivo. Western blot analysis was carried out to determine the effect of silibinin on the expression of PDGF receptor and on the downstream signaling pathways regulated by PDGF receptor. PDGF elevated the expression of PCNA in HTFs, and this elevation was inhibited by silibinin. The inhibitory effect of silibinin on cell proliferation was also confirmed via WST-1 assay. PDGF-stimulated cell cycle in HTFs was delayed by silibinin, and the related cyclin D1 and CDK4 were also suppressed by silibinin. In the rat model of trabeculectomy, silibinin reduced the expression of PCNA at the site of blebs in vivo. The effects of silibinin on PDGF-stimulated HTFs were mediated via the downregulation of PDGF receptor-regulated signaling pathways, such as ERKs and STATs, which may be partially caused by the downregulation of N-glycosylation of PDGF receptor beta (PDGFRß). The effect of silibinin on modulation of N-glycosylation of PDGFRß was mediated in a proteasome-dependent manner. Silibinin inhibited cell proliferation and delayed cell cycle progression in PDGF-treated HTFs in vitro. PDGF also modulated the process of N-glycosylation of the PDGFRß in a proteasome-dependent manner. Our findings suggest that silibinin has potential therapeutic applications in glaucoma filtering surgery.

Details of the Collagen and Elastin Architecture in the Human Limbal Conjunctiva, Tenon's Capsule and Sclera Revealed by Two-Photon Excited Fluorescence Microscopy.

PURPOSE: To investigate the architecture and distribution of collagen and elastin in human limbal conjunctiva, Tenon's capsule, and sclera. METHODS: The limbal conjunctiva, Tenon's capsule, and sclera of human donor corneal buttons were imaged with an inverted two-photon excited fluorescence microscope. No fixation process was necessary. The laser (Ti:sapphire) was tuned at 850 nm for two-photon excitation. Backscatter signals of second harmonic generation (SHG) and autofluorescence (AF) were collected through a 425/30-nm and a 525/45-nm emission filter, respectively. Multiple, consecutive, and overlapping (z-stack) images were acquired. Collagen signals were collected with SHG, whereas elastin signals were collected with AF. RESULTS: The size and density of collagen bundles varied widely depending on depth: increasing from conjunctiva to sclera. In superficial image planes, collagen bundles were <10 µm in width, in a loose, disorganized arrangement. In deeper image planes (episclera and superficial sclera), collagen bundles were thicker (near 100 µm in width) and densely packed. Comparatively, elastin fibers were thinner and sparse. The orientation of elastin fibers was independent of collagen fibers in superficial layers; but in deep sclera, elastin fibers wove through collagen interbundle gaps. At the limbus, both collagen and elastin fibers were relatively compact and were distributed perpendicular to the limbal annulus. CONCLUSIONS: Two-photon excited fluorescence microscopy has enabled us to understand in greater detail the collagen and elastin architecture of the human limbal conjunctiva, Tenon's capsule, and sclera.

Stage-specific differentiation of iPSCs toward retinal ganglion cell lineage.

PURPOSE: As an alternative and desirable approach for regenerative medicine, human induced pluripotent stem cell (hiPSC) technology raises the possibility of developing patient-tailored cell therapies to treat intractable degenerative diseases in the future. This study was undertaken to guide human Tenon's capsule fibroblasts-derived iPSCs (TiPSCs) to differentiate along the retinal ganglion cell (RGC) lineage, aiming at producing appropriate cellular material for RGC regeneration. METHODS: By mimicking RGC genesis, we deliberately administered the whole differentiation process and directed the stage-specific differentiation of human TiPSCs toward an RGC fate via manipulation of the retinal inducers (DKK1+Noggin+Lefty A) alongside master gene (Atoh7) sequentially. Throughout this stepwise differentiation process, changes in primitive neuroectodermal, eye field, and RGC marker expression were monitored with quantitative real-time PCR (qRT-PCR), immunocytochemistry, and/or flow cytometry. RESULTS: Upon retinal differentiation, a large fraction of the cells developed characteristics of retinal progenitor cells (RPCs) in response to simulated environment signaling (DKK1+Noggin+Lefty A), which was selectively recovered with manual isolation approaches and then maintained in the presence of mitogen for multiple passages. Thereafter, overexpression of ATOH7 further promoted RGC specification in TiPSC-derived RPCs. A subset of transfected cells displayed RGC-specific expression patterns, including Brn3b, iSlet1, calretinin, and Tuj, and approximately 23% of Brn3b-positive RGC-like cells were obtained finally. CONCLUSIONS: Our DKK1+Noggin+Lefty A/Atoh7-based RGC-induction regime could efficiently direct TiPSCs to differentiate along RGC lineage in a stage-specific manner, which may provide a benefit to develop possible cell therapies to treat retinal degenerative diseases such as glaucoma.

Paclitaxel inhibits cell proliferation and collagen lattice contraction via TGF-ß signaling pathway in human tenon's fibroblasts in vitro.

As an anti-microtubule agent, paclitaxel has been widely applied clinically. However, the effects of paclitaxel on human tenon's fibroblast (HTF) proliferation and migration in vitro was still unclear. In the present study, we explored the influences of paclitaxel on HTF cell proliferation, cell viability, cell cycle phase distribution under various concentrations of paclitaxel (i.e., 0, 10(-8), 10(-7), 10(-6)mol/l) via real-time cell electronic system and flow cytometry, further determined the expression of TGF-ß1 and connective tissue growth factor (CTGF) after treatment with different concentrations of paclitaxel. Moreover, extra cellular matrix production and collagen lattice contraction assay were also explored. The results indicate that paclitaxel could apparently inhibit the cell viability, induces the elevation of S and G2/M phases of HTFs, and downregulates the expression of both TGF-ß1 and CTGF. Meanwhile, the levels of fibronectin extra domain A (EDA), collagen and collagen lattice contraction were apparently reduced after treatment with paclitaxel. Overall, paclitaxel could apparently inhibit the proliferation of HTFs and leads to cell cycle arrest at both S and G2/M phases, attenuates the generation of collagen and collagen lattice contraction, decreases the expressions of TGF-ß1, CTGF and fibronectin EDA. The inhibitory mechanism of paclitaxel on HTFs is involved in TGF-ß1 signaling pathway.

GMP-grade platelet lysate enhances proliferation and migration of tenon fibroblasts.

Tenon's fibroblasts (TFs), widely employed as in vitro model for many ophthalmological studies, are routinely cultured with FBS. Platelet Lysate (PL), a hemoderivate enriched with growth factors and cytokines has been largely tested in several clinical applications and as substitute of FBS in culture. Here, we investigate whether PL can exert biological effects on TF populations similarly to other cell types. Results show that PL significantly enhances cell proliferation and migration vs. FBS, without influencing cell size/granularity. Upregulation of EGF, VEGF, KDR, MMP2-9, FAK mRNA levels also occurs and phosphorylation of AKT but not of ERK1/2 is significantly enhanced. The inhibition of the PI3kinase/AKT pathway with the specific inhibitor wortmannin, decreases PL-induced cell migration but not proliferation. Condition supernatants containing PL show increased bioavailability of Nitric Oxide and reduced levels of 8-Iso-PGF2-alpha, correlating with cell proliferation and migration. Pro-angiogenic/inflammatory soluble factors (GRO, Angiogenin, EGF, I-309, PARC) are exclusively or greater expressed in media containing PL than FBS. GMP-grade PL preparations positively influence in vitro biological effects of TFs representing a suitable and safer alternative to FBS.

Effects of ranibizumab on TGF-ß1 and TGF-ß2 production by human Tenon's fibroblasts: An in vitro study.

PURPOSE: Inhibiting exaggerated wound healing responses, which are primarily mediated by human Tenon's fibroblast (HTF) migration and proliferation, has become the major determining factor for a successful trabeculectomy. Antivascular endothelial growth factor (anti-VEGF) has showed promising results as a potential antifibrotic candidate for use concurrently in trabeculectomy. Preliminary cohort studies have revealed improved bleb morphology following trabeculectomy augmented with ranibizumab. However, the effects on HTFs remain unclear. This study was conducted to understand the effects of ranibizumab on transforming growth factor (TGF)-ß1 and transforming growth factor (TGF)-ß2 expression by HTFs. METHODS: The effect of ranibizumab on HTF proliferation and cell viability was determined using 3-(4,5-dimethylthiazone-2-yl)-2,5-diphenyl tetrazolium (MTT) assay. 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 TGF-ß1 and TGF-ß2 mRNA and protein levels using quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). RESULTS: At 48 h, 0.5 mg/ml of ranibizumab significantly induced cell death under serum-free culture conditions (p<0.05). Ranibizumab caused a significant reduction in TGF-ß1 mRNA, but not for TGF-ß2. However, the total protein production of TGF-ß1 and TGF-ß2 was unaffected by this anti-VEGF treatment. CONCLUSIONS: Exposure of HTFs to an intravitreal dose of ranibizumab significantly suppresses cell viability in vitro; however, the application seemed unable to affect the ultimate production of TGF-ß. Therefore, we highlighted ranibizumab as a potential antiscarring agent that acts via a different mechanism when used synergistically with another antifibrotic agent. Understanding the mechanism of actions of ranibizumab offers an additional view of a possible new rational therapeutic strategy.

In vitro characteristics of Tenon's fibroblast lines derived from pediatric and adult eyes do not fully explain pediatric glaucoma surgery failure: a preliminary report.

PURPOSE: To compare the in vitro characteristics of Tenon's capsule fibroblasts from children and adults that may be relevant to filtration surgery success. METHODS: Fibroblast cell lines derived from 5 young (median patient age, 2.4 years) and 7 old (median patient age, 71 years) discarded Tenon's capsule surgical specimens were used at early passage (P2-P3). Fibroblasts were plated at "high" (10(4)cells/cm(2)) or "low" density (10(3)cells/cm(2)) and harvested at days 0-14, for growth curve and doubling time comparisons. Migration was measured using a wound model (confluent monolayers ± 5-fluorouracil [5-FU] over 1-96 hours). Collagen synthesis was measured as secreted hydroxyproline/24 hours from confluent monolayers. RESULTS: At low density, "young" fibroblasts achieved higher cell numbers at confluence (day 14) compared with "old": 158 ± 35 versus 105 ± 12 × 10(3)cells/cm(2) (P = 0.0034). Mean doubling time for young versus old was similar at low density plating: 20.95 ± 1.55 versus 22.37 ± 2.09 hours (P = 0.26). It was shorter, however, for young versus old at high-density plating: 42.11 ± 6.01 versus 54.26 ± 4.24 hours (P = 0.0051). Wound closure rates were similar for young versus old cells (4 lines for each group) with and without 5-FU. Collagen synthesis was similar for young and old (4 lines for each group). CONCLUSIONS: Although young fibroblasts reached higher density than old at confluence and had shorter doubling times at high-density plating, wound closure/migration and collagen synthesis rates were similar. Despite the preliminary nature of this study (few specimens, limited cell features explored), factors besides those intrinsic to the fibroblasts themselves likely mediate the more rapid healing/scarring after glaucoma filtration surgery in children.

Expression of protein kinase C isoforms in cultured human Tenon's capsule fibroblast cells.

Members of the protein kinase C (PKC) family are involved in physiological and pathophysiological processes, and exert an important role in signal transduction. The aim of the present study was to determine which of the 12 protein kinase C (PKC) isoforms (PKCα, PKCßⅠ, PKCßⅡ, PKCγ, PKCδ, PKCε, PKCη, PKCθ, PKCµ, PKCζ, PKCλ and PKCι) were expressed in vitro in cultured human Tenon's capsule fibroblasts (HTFs). HTFs from cell passages three to five were investigated for the presence of the 12 PKC isoforms at the cellular, mRNA and protein levels using laser scanning confocal microscopy (LSCM), reverse transcription­polymerase chain reaction (RT­PCR) and western blot analysis, respectively. These analyses yielded similar results for several of the PKC isoforms (PKCα, PKCδ, PKCε, PKCη, PKCµ, PKCζ, PKCλ and PKCι); however, PKCßⅠ, PKCßⅡ, PKCγ and PKCθ were not expressed in the cultured HTFs. LSCM revealed that eight PKC isoforms, PKCα, PKCδ, PKCε, PKCη, PKCµ, PKCζ, PKCλ and PKCι, appeared almost exclusively in the cytoplasm of the cells. Notably, PKCδ was expressed particularly well in the cytoskeleton. The present study revealed that all 12 PKC isoforms were expressed and that eight of the isoforms were present in cultured HTFs. These results will be of value when determining specific roles for the PKC isoforms in HTF proliferation, which may provide a novel therapeutic target for bleb scarring in glaucoma filtering surgery.