Human Tenon's Capsule Fibroblasts Research Articles

Expression and Regulation of LOXL1 and Elastin-related Genes in Eyes With Exfoliation Syndrome

Exfoliation syndrome (XFS) is a complex, late-onset disorder of the elastic fiber system and the most common identifiable cause of open-angle glaucoma. Strong genetic risk is conferred by the lysyl oxidase-like 1 (LOXL1) gene, but additional comodulating factors are necessary for the manifestation of the disease. The aim of this study was to establish a comprehensive expression profile of LOXL1 and elastic proteins in XFS eyes and to analyze their regulation in an in vitro cell culture system. Eyes with XFS with and without glaucoma, and normal control eyes were analyzed for major elastic fiber components (elastin, fibrillin-1, fibulin-4), and lysyl oxidase (LOX) enzymes by real-time PCR, immunohistochemistry, and electron microscopy. Cultured human Tenon's capsule fibroblasts were exposed to transforming growth factor-β1, IL-6, homocysteine, oxidative stress, hypoxia, or ultraviolet radiation, and changes in the expression of LOXL1 and elastic components of XFS material were assessed by real-time PCR, immunohistochemistry, and Western blotting. LOXL1 expression in anterior eye tissues was significantly increased in early XFS stages but was decreased in advanced stages as compared with controls. LOXL1 was also found to be a major component of XFS material and to colocalize with elastin, fibrillin-1, and fibulin-4, which were upregulated in parallel to LOXL1. In contrast, in most posterior segment tissues, LOXL1 and elastic fiber proteins displayed no differential expression. Interestingly, lamina cribrosa specimens of early and late XFS stages without and with glaucoma revealed a selective downregulation of LOXL1 and elastic fiber components on the mRNA and protein level, which was associated with pronounced ultrastructural alterations of the laminar elastic fiber network in XFS eyes. Treatment of cultured cells with XFS-associated pathogenetic stimuli induced a significant increase in the expression of LOXL1 and elastic proteins and resulted in their assembly into XFS-like fibrils in vitro. The findings support the notion that both genetic and nongenetic factors may cooperate in the stable accumulation of XFS aggregates and provide evidence for a XFS-specific elastinopathy of the lamina cribrosa, possibly rendering XFS eyes more vulnerable to pressure-induced optic nerve damage and glaucoma development.

Investigation on novel chitosan nanoparticle–aptamer complexes targeting TGF-β receptor II

In our previous study, a dominant sequence called aptamer S58 antagonized TGF-β-induced myofibroblast transdifferentiation in human Tenon's capsule fibroblasts (HTFs) through sealing the targeting site of TGF-β receptor II (TβR II). However, rapid degradation by ubiquitous nucleases limited the aptamer's efficacy. Chitosan-nanoparticles (CS-NP) are good drug carriers. Herein we synthesises novel chitosan nanoparticle-aptamer S58 complexes called CS(S58)-NP in order to preserve and prolong S58's efficacy. We synthesised CS(S58)-NP at various molar ratios of CS-NP to S58 using an ionic gelation method. Then, the properties of the CS(S58)-NP including particle size, zeta potential, protection capacity, slow-release effect and cytotoxicity were studied. The targeting effect of the CS(S58)-NP was also studied. CS(S58)-NP at molar ratios of 20 and 30 showed high aptamer encapsulation efficiency, powerful aptamer protection, stable sustained-release ability and low cytotoxicity. FITC-labelled CS(S58)-NP could successfully bind to TβR II. As a result, TGF-β-induced cell proliferation and α-SMA expression were both inhibited. Furthermore, the CS(S58)-NP could inhibit TGF-β-induced α-SMA expression for a longer time than naked S58, even in serum. This research applied CS-NP as the aptamer carrier. The research results demonstrate that CS-NP are potentially able to preserve and prolong aptamer S58's efficacy. This study reveals that the use of CS-NP is promising for aptamer delivery and CS(S58)-NP can be a potential anti-scarring therapeutic approach after glaucoma filtration surgery.

Hydroxycamptothecin Induces Apoptosis of Human Tenon's Capsule Fibroblasts by Activating the PERK Signaling Pathway

Hydroxycamptothecin (HCPT) has been proven to induce apoptosis in fibroblasts. In this study, we investigated whether the PRKR-like ER kinase (PERK) pathway is implicated in apoptotic signaling of human Tenon's capsule fibroblasts (HTCFs) by HCPT. Normal and PERK-knockdown HTCFs were used in this study. Apoptosis was determined by the cell viability assay, Annexin V/propidium iodide (PI) dual-staining, cell cycle analysis in HTCFs treated with HCPT in various doses and for various durations. Endoplasmic reticulum (ER) stress markers and sensor proteins were detected by Western blot analysis. Mitochondrial dysfunction was measured by detecting the mitochondrial membrane potential (ΔΨm) and measuring the expression of cytochrome c (cyt c). HCPT induced apoptosis in the HTCFs, which was characterized as decreased cell viability and sub-S fraction of the cell cycle and increased apoptosis rate by Annexin V/PI dual-staining. The activity levels of caspase-3 and caspase-9 were significantly increased and were accompanied by cytosolic release of cyt c and decreased ΔΨm in response to HCPT. Treatment with HCPT increased the expression of glucose-regulated protein 78 (GRP78), phospho-PERK, activating transcription factor 6 (ATF6), phosphoinositol-requiring kinase 1 (IRE1), C/EBP homologous protein (CHOP), Bax, and phospho-c-Jun N-terminal kinase (JNK) and decreased the expression of Bcl-2. Knockdown of PERK attenuates HCPT-induced apoptosis in HTCFs, dependent upon both ER stress and the mitochondrial apoptotic pathway. This study suggests that the ER stress response and mitochondrial dysfunction are involved in apoptosis induced by HCPT in HTCFs, which might be mediated by PERK; thus, this study offers new insight into preventing postoperative scarring via treatment with HCPT.

Hydroxycamptothecin-induced apoptosis of human Tenon capsule fibroblast and its mechanism

Background The hyperplasia of human Tenon capsule fibroblasts (HTFs) is a common cause of filtering surgery failure in glaucomous eye.Researches demonstrated that hydroxycamptothecin is a cell cycle arresting drug and induce apoptosis of cancer and fibroblasts.However,its mechanism is currently less understood.Objective This study was to investigate whether hydroxycamptothecin induce the apoptosis of HTFs and explore the possible mechanism.Methods Human Tenon capsule tissue was obtained from EyeBank of Jiangsu Province Hospital.HTFs were cultured using explant method in vivo and passaged in DMEM containing 10％ FBS.The cells were identified using vimentin and keratin by immunochemistry,and the cells of generation 3-6 in the logarithmic growth phase were used in the experiment.The cells were incubated with 0.01,0.05 or 0.10 g/L hydroxycamptothecin for 5 minutes respectively,and the cells without any hydroxycamptothecin were served as the control group.Cell viability then was assessed by cell counting kit-8 (CCK8) for the optimal inhibition concentration.The cells were treated by 0.10 g/L hydroxycamptothecin for 24 hours,and the apoptotic rate of the cells were assayed with annexin V/PI double-staining.Mitochondrial membrane potential of HTFs was assessed using JC-1 staining.The expressions of caspase-3,caspase-9 and cytochrome C (cyt C) in mitochondria and cytoplasm of HTFs were detected by Western blot.Results The proliferative value (A450) of the HTFs 0,0.01,0.05,0.10 g/L was 0.9716±0.0608,0.8035 ± 0.0346,0.7048 ±0.0446,0.6265 ±0.0286,with a significant difference (F =26.372,P =0.002).A450 of HTFs in the 0.01,0.05,0.10 g/L groups was significantly lower than the control group (P＜0.05),with the lowest A450 value in the 0.10 g/L group.The apoptotic percentage of HTFs was (18.72±1.41)％,in the 0.10 g/L hydroxycamptothecin group and that of the control group was (3.67 ±0.36)％,showing a significant difference between them (t =-10.374,P=0.001).The expression intensity of caspase-3 and caspase-9 protein in HTFs was higher in the 0.10 g/L hydroxycamptothecin group than that in the control group.JC-1 staining showed that the green fluorescence of the monomer JC-1 in cytoplasm was stronger in the 0.10 g/L hydroxycamptothecin group than that in the control group,but the red fluorescence of the polymer JC-1 in the 0.10 g/L hydroxycamptothecin group was weaker than that in the control group.The grey scale of cyt C protein in HTFs in mitochondrion was 0.0605±0.0022 in the 0.10 g/L hydroxycamptothecin group,showing a significant increase in comparison with 0.0301 ±0.0016 of the control group (t=4.865,P=0.014).However,the grey scale of cyt C protein in cytoplasm was declined in the 0.10 g/L hydroxycamptothecin group than that in the control group (0.0605 ±0.0022 vs.0.0301 ±0.0016) (t =-11.177,P =0.001).Conclusions Hydroxycamptothecin can induce the apoptosis of HTFs through activating the mitochondrial apoptosis pathway. Key words: Hydroxycamptothecin; Fibroblast; Mitochondria apoptosis pathway; Glaucoma

Inhibitory effect of apigenin on human Tenon capsule fibroblasts

Background Proliferation of the human Tenon capsule fibroblasts(HTFs) is a main cause of failure of filtering surgery.To search the drug of inhibiting the growth of the HTFs is essential for the improvement of successful rate of filtering surgery.Objective The aim of this study was to investigate the inhibitory effect of apigenin on HTFs and its mechanism.Methods Human Tenon capsular tissue was obtained during the strabismus correction surgery.HTFs was primarily cultured using explant method and identified using vimentin by immunochemistry.The 3-5 generation of cells were incubated to 96-well plate.Apigenin of 0,20,40,80,160 μmol/L was added into the medium,respectively,for 24,48,72 hours,and the proliferation of HTFs was detected by sulfonyl chloride (SRB) at the wavelength of 560 nm (A560).Bromodeoxyuridine (BrdU) of 10 μg/L was added to culture the cells for 48 hours to calculate the labeling rate of BrdU.The morphology of the cells was observed using Hoechst 33258 staining,and apoptosis and cells cycle were evaluated by flow cytometry.Results Cultured cells grew well with the positive response for vimentin,showing the green fluorescence in cytoplasm.SRB assay showed that the A560 value was gradually declined with the increase of the dosage of apigenin and prolong of time (Fgroup =480.306,P =0.000 ; Ftime =555.144,P =0.000).The labeling rate after 0,40,80 μmol/L apigenin acted for 48 hours was (87.860 ±0.632)％,(61.520±4.306)％ and (23.480±4.472)％,showing a significant difference among the three groups (F =299.347,P =0.000).The labeling rate of HTFs for BrdU was significantly decreased in the 40 and 80 μmol/L apigenin groups compared with the 0 μmol/L apigenin group (P＜0.05).Hoechse 33258 staining found that the number of the HTFs was gradually decreased and the cell number of karyopyknosis and nuclear deformation was increased with the increase of apigenin dosage.Percentage of cells in G0/G1 phase were raised and that in S and G2/M phase were declined in the higher dosage apigenin group,with a significant difference among the different groups (FG0/G1 =58.621,P=0.000;Fs =32.357,P=0.001 ;FG2/M =83.998,P=0.000).In the 72nd hour after acted by 0,40,80,160 μmol/L apigenin,the apoptosis rate of HTFs was (4.77±0.21) ％,(13.24±1.35)％,(18.33±1.86) ％,(31.58 ± 2.77) ％,respectively,with a statistically significant difference among the four groups (F =204.791,P＜0.05).Conclusions Apigenin restrains the growth of HTFs by evoking G0/G1 cell cycle arrest and inducing apoptosis in a dosage-and time-dependent manner. Key words: Apigenin; Human Tenon capsule fibroblast; Apoptosis

RNA Interference Targeting Connective Tissue Growth Factor Inhibits the Transforming Growth Factor-β2Induced Proliferation in Human Tenon Capsule Fibroblasts

Purpose. This study was to determine the effect of CTGF-small interfering RNA (siRNA) on TGF-β 2-induced proliferation in human Tenon capsule fibroblasts (HTFs). Methods. HTFs were transfected with four of CTGF-siRNAs separately for screening of gene silencing efficacy that was determined by transcript level measured by quantitative real-time PCR (qRT-PCR). Recombinant TGF-β 2 was added into the culture to stimulate the proliferation of HTFs. The gene silencing efficacy of the siRNAs was evaluated by qRT-PCR and immunofluorescence of CTGF transcript and protein levels. The viability of HTFs was determined by cell counting kit-8 (CCK-8). FCM was used to assess cell cycle after CTGF-siRNA transfection. Results. The expression of CTGF and proliferation of HTFs were increased significantly by TGF-β 2 stimulation. The transfection of CTGF-siRNA abolished the upregulation of CTGF and cell proliferation induced by TGF-β 2. The analysis of cell cycle indicated that CTGF-siRNA treatment stimulated cells from S phase to G0/G1 phase in comparison with the inverse physiologic function of TGF-β 2. Conclusion. CTGF targeting siRNA could effectively suppress the expression of CTGF and attenuate the proliferation of HTFs. The siRNA approach may provide a therapeutic option for eliminating filtration bleb scarring after glaucoma filtration surgery (GFS).

Genetic/Epigenetic Modulation, Ocular Diseases, and Therapeutic Prospective

Complex eye diseases often have significant genetic components. Previous work exploring the genetic contributions of ocular diseases has implicated numerous genomic regions and a variety of candidate genes as modulators of the disease susceptibility, including cataract, age-related macular degeneration (AMD), diabetic retinopathy (DR), glaucoma, high myopia, and others. With the advance of techniques both on genotyping and phenotyping, additional genes with a role in complex eye disease are waiting to be discovered. In contrast, it is apparent that a significant portion of the heritability of ocular disease cannot be explained through the alteration of DNA sequences. The field of epigenetics pursues the changes in gene expression or cellular phenotypes caused by mechanisms other than changes in the underlying DNA sequence. In general, epigenetic changes pertain to DNA methylation and histone modification. Aberrant epigenetic changes are associated with genomic instability and have been implicated in various human diseases. Recent advances in high-throughput platforms can generate voluminous data, which requires desperately the tools of system biology to effectively elucidate the true pictures underlying them. Knowledge and understanding of these genetic components and pathways have led to the development of promising therapies including small inference RNA (siRNA). This special issue contains 5 articles, the contents of which are summarized as follows. In the original paper “An extensive replication study on three new susceptibility loci of primary angle closure glaucoma in Han Chinese: Jiangsu Eye Study” by A. Shi et al., the authors tried to replicate recent findings of three new susceptibility loci for primary angle closure glaucoma (PACG) reported by a genome-wide association study. For a long time, the genetic study on glaucoma has been focused on primary angle open glaucoma. Instead of using clinical diagnosis of PACG as the phenotype to study, the authors chose a preclinical condition, primary angle closure (PAC), and same anatomical features of eyes to investigate. This community-based study did not find any significant association between the defined phenotypes and the single nucleotide polymorphisms in PLEKHA7, COL11A1, and PCMTD1-ST18. In the review paper “Vascular adhesion protein 1 in the eye” by W. Luo et al., the authors gave an overview on the new research progresses of VAP-1 in the ocular diseases including uveitis, AMD, DR, and ocular tumor. Based on the properties and results obtained so far from preclinical and clinical studies VAP-1 may provide a novel research direction or a potent therapeutic strategy for ophthalmological diseases. In the original paper “RNA interference targeting connective tissue growth factor inhibits the transforming growth factor-β2 induced proliferation in human Tenon capsule fibroblasts” by J. Jing et al., the authors showed that siRNA could efficiently prevent TGF-β2 induced proliferation of human Tenon capsule fibroblast, through targeting CTGF gene expression. Therefore, a siRNA based therapeutic approach was proposed for eliminating filtration bleb scarring after glaucoma filtration surgery. In the original paper “RNA interference targeting snail inhibits the transforming growth factor β2-induced epithelial-mesenchymal transition in human lens epithelial cells” by P. Li et al., the authors tested the concept to use Snail targeting siRNA to block TGF β2-induced proliferation in human lens epithelial cells. The results show that epithelial-mesenchymal transition was inhibited by Snail targeting siRNA in the model system that the article described, accompanied by the suppression on snail expression. The finding is informative for the design of the preventive strategy on posterior capsule opacification after cataract surgery. In the original paper “Systems biology profiling of AMD on the basis of gene expression” by M. S. Abu-Asab et al., a systems biology analytical paradigm called parsimony phylogenetics was used to reveal the various transcriptomic profiles of AMD's subtypes. Genetic pathways underlying the initiation and progression of AMD and the correlations of AMD's genotypes, phenotypes, and disease spectrum were investigated. On the whole, the papers contained in this special issue covered the most active fields of genetic studies on complex eye diseases. Jingsheng Tuo Lai Wei Nan Hu

Induction and Mechanism of Apoptosis by Hydroxycamptothecin in Human Tenon's Capsule Fibroblasts

We investigated apoptosis induced by hydroxycamptothecin (HCPT) in human Tenon's capsule using fibroblasts cultured from human Tenon's capsule (HTFs), and the mechanism of induction. HTFs were treated with 0-4 mg/L HCPT for 24 hours. Cell proliferation was measured by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, and apoptotic cells were analyzed by Hoechst 33258 stain. The mRNA and protein levels of caspase-3, -8, and -9 were detected by RT-PCR and Western blotting. By MTT assay, HCPT induced apoptosis in HTFs in a concentration- and time-dependent manner. Hoechst 33258 staining and transmission electron microscopy showed typical apoptotic morphology, such as condensed chromatin, irregular nuclei, and apoptotic body formation. The mRNA and protein levels of caspase-3 and caspase-9 were upregulated, while caspase-8 was unchanged. Z-VAD-FMK, a caspase inhibitor, inhibited the apoptosis of fibroblasts induced by HCPT. The expression levels of caspase-3 and caspase-9 were down-regulated after Z-VAD-FMK treatment. Caspase-3 and caspase-9 are important elements in regulating HCPT-induced apoptosis in HTFs.

Alpha-melanocyte stimulating hormone suppresses the proliferation of human Tenon’s capsule fibroblast proliferation induced by transforming growth factor beta 1

Alpha-melanocyte stimulating hormone (alpha-MSH) is a proopiomelanocortin derivative and a multi-function neuropeptide, well know for its pigment-inducing capacity, inhibitory action on proinflammatory cytokines and chemoattractant cytokines, and suppressive action on collagen synthesis. Human Tenon's capsule fibroblasts (HTF) are the main effector cells in the initiation and mediation of wound healing and fibrotic scar formation after trabeculectomy. In this study the effects of alpha-MSH on proliferation of HTF stimulated by transforming growth factor beta1 (TGF-beta1), have been investigated and discussed. Fibroblasts were cultured in Dulbecco's modified Eagle's medium (DMEM) in the control group, and in DMEM with TGF-beta1 at concentration of 10(-12) M in the TGF-beta1 group, and DMEM with 10(-12) M TGF-beta1 and alpha-MSH ranging from 0, 10(-8) to 10(-4) M in the TGF-beta1/alpha-MSH groups. Cell proliferation was assessed 48 h later by the CellTiter 96 Aqueous One Solution Cell Proliferation Assay. After administration of TGF-beta1 at a concentration of 10(-12) M, or TGF-beta1 at 10(-12) M plus alpha-MSH at 10(-6) M, the mRNA level of type I (alpha1) collagen, fibronectin, TNF-alpha, intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), MMP-1, MMP-2, TIMP-1, and TIMP-2 in HTF were analyzed using the real time reverse transcription polymerase chain reaction. Alpha-MSH demonstrated an inhibitory effect on the proliferation of HTF induced by TGF-beta1 in a dose-dependent manner, when the concentration was lower than 10(-5) M, and a suppressive effect on the mRNA expression of type I (alpha1) collagen, TNF-alpha, ICAM-1 and VCAM-1, which were up-regulated by TGF-beta1. Our results showed a reverse effect of alpha-MSH on the imbalance between MMPs and TIMPs compared with TGF-beta1. Based on all these results, we conclude that alpha-MSH could effectively suppress HTF proliferation and modulate correlative genes in collagen synthesis stimulated by TGF-beta1, which implies that alpha-MSH could be exploited in the treatment of conjunctival fibrotic scar disorder.

Effect of tetrandrine eye drops on expression of apoptotic protein and transforming growth factor-β2 in human Tenon capsule fibroblast in vitro

Background Our previous study determined that tetrandrine (Tet) has an inhibitory effect on the proliferation of human Tenon capsule fibroblasts ( TCFs ) in vitro,but its mechanism is poorly understood.Objective This study was to investigate the effect mechanism of Tet on human TCFs. Methods Human TCFs were isolated and cultured from scleral tissue of donor using explant technique.The cells were identified by vimentin antibody staining and morphology.The third generation of cells were seeded in the culture plate at the density of 1 × 105 cells/ml.Twenty-four hours after inoculation,the Tet of 1 × 10-5 mol/L was added in the well of culture plate,and the cells cultured only in 1640 medium served as the control group.The apoptosis of the cells was assessed by TUNEL,and the expressions of bax,bel-2,transforming growth factor-β2 (TGF-β2 ) in TCFs were detected using immunochemistry. Results The cultured cells showed the features of the fibroblasts in shape with the positive response for vimentin.A number of TUNEL positive cells were seen in Tet group and no TUNEL positive response was found in control group.The expression levels (A value) of bax,bcl-2 and TGF-~ protein in TCFs were 0.577 ± 0.009,0.430±0.012 and 0.341 ±0.017 in Tet group,and those in control group were 0.320±0.015,0.819±0.021 and 0.624±0.014 respectively,showing statistically significant differences between two groups( t =33.277,-35.356,-28.093,P＜0.01 ). Conclusions Tet suppresses the proliferation of human TCFs through up-regulating the expression of bax and down-regulating the expressions of bcl-2 and TGF-β2 in vitro. Key words: Tetrandrine; Tenon capsule fibroblast; Apoptosis-related protein/bax, bcl-2; Tansforming growth factor β2 protein

Regulation of Lysyl Oxidase-like 1 (LOXL1) and Elastin-Related Genes by Pathogenic Factors Associated with Pseudoexfoliation Syndrome

Pseudoexfoliation (PEX) syndrome/glaucoma is a complex, late-onset disorder of the elastic fiber system. Strong genetic risk is conferred by the lysyl oxidase-like 1 (LOXL1) gene, but additional comodulating factors are necessary for the manifestation of the disease. The aim of this study was to analyze the effect of various PEX-associated pathogenic factors on the genotype-correlated expression of LOXL1 and elastin-related genes. Cultured human Tenon's capsule fibroblasts with high- and low-risk LOXL1 haplotypes were exposed to transforming growth factor (TGF)-β1, interleukin (IL)-6, homocysteine, oxidative stress, hypoxia, or ultraviolet (UV) radiation. Changes in the expression of LOXL1 and elastic constituents of PEX material and TGF-β1 were assessed by quantitative real-time PCR, Western blotting, immunohistochemistry, and electron microscopy. Treatment of fibroblasts with TGF-β1, oxidative stress, UV light, and hypoxia induced a significant increase in expression levels of LOXL1 and elastic proteins, whereas the effect of IL-6 was limited to induction of elastic constituents. Immunohistochemistry and electron microscopy confirmed an upregulation of LOXL1 and elastic fiber proteins and their assembly into extracellular microfibrillar networks with focal aggregation of microfibrils into PEX-like fibrils on stimulation with TGF-β1 and oxidative stress. Basal and stimulated expression of LOXL1 mRNA and protein was slightly decreased in cells carrying the high-risk compared with the low-risk haplotype of LOXL1, but the differences between groups were statistically not significant. The findings support the notion that both genetic and nongenetic fibrogenic factors, particularly TGF-β1 and oxidative stress, may cooperate in the stable accumulation of PEX aggregates.

Target drug delivery system as a new scarring modulation after glaucoma filtration surgery

BackgroundExcessive wound healing following glaucoma filtration surgery is the main determinant of surgical failure, resulting from the activation of human Tenon's capsule fibroblasts (HTFs). To mitigate the excessive wound healing, the topicall use of antiproliferative agents, such as mitomycin C (MMC) and 5-fluorouracil (5-FU), has increased the surgery success rate, but the traditional administration of these agents can result in a variety of toxicities with nonspecific damage. However, modulation of the wound healing process to prevent excessive fibroblast proliferation and scar formation can play a major role in improving the outcome of surgery. Therefore, the search for alternative modes of drug delivery and new agents is needed to minimize the ocular complications and improve the success of surgery. We have shown that there is a postoperative overexpression of the LDL receptor (LDLr) in the activated HTFs may provide a novel target for drug delivery systems.Presentation of the HypothesisWe hypothesize that antifibrotic agents (MMC) encapsulated in LDLr targeting drug delivery system (LDL-MMC-chitosan nanoparticles) may be proposed in anti-scarring therapy to increase the safety and effectiveness and to reduce toxicity.Testing the HypothesisA chitosan-based polymeric predrug of MMC was synthesized and its cytotoxicity was proved to be low. In addition, we propose hyaluronic acid film as a container to release LDL-MMC-chitosan nanoparticles gradually at subconjunctival filtering site after glaucoma filtration surgery to eliminate the LDL-MMC-chitosan nanoparticles.Implications of the Hypothesis and discussionThis strategy can be applicable to anti-scarring therapy during excessive conjunctival wound healing. This hypothesis integrates advantages of the targeting drug delivery and antifibrotic agents, such as high efficiency, convenience, and lower the toxicity.

Autophagy of Human Tenon's Capsule Fibroblasts Induced by Mitomycin-C

Autophagy of Human Tenon's Capsule Fibroblasts Induced by Mitomycin-C

Potentiation of Bortezomib-Induced Apoptosis by TGF-β in Cultured Human Tenon's Fibroblasts: Contribution of the PI3K/Akt Signaling Pathway

To investigate the effects of bortezomib on cell apoptosis and proliferation in human Tenon's capsule fibroblasts (HTFs) after cotreatment with TGF-β. The effect of bortezomib on the apoptosis and cell proliferation of cultured HTFs was determined with FACS analysis and 3-[4,5-demethylthiazol-2,5-diphenyl-2H-tetrazolium bromide] (MTT) assay with or without cotreatment of TGF-β. The apoptotic effect of cotreatment of bortezomib and TGF-β through the PI3K/Akt pathway was determined by Western blot analysis. The mRNA level of Bcl-2 and Bax was determined by RT-PCR. p53 expression, DNA-PKcs cleavage, and c-Jun phosphorylation were determined. Cotreatment with bortezomib (5 μM) and TGF-β (10 μM) increased the proportion of apoptotic cells in HTFs on FACS analysis, whereas either bortezomib or TGF-β treatment alone did not. The MTT assay also showed that when bortezomib was cotreated with TGF-β, the cell proliferation of HTFs induced by TGF-β treatment was significantly decreased at 72-hour incubation. The cotreatment of bortezomib and TGF-β specifically decreased the Akt phosphorylation induced by TGF-β, indicating on Western blot analysis that these changes are mediated by the PI3K/Akt pathway. The mRNA level of an apoptosis-related factor, Bcl-2, was significantly reduced, and p53 expression, DNA-PKcs cleavage, and c-Jun phosphorylation were increased after cotreatment. Bortezomib-induced apoptosis is potentiated by TGF-β cotreatment in cultured HTFs by inhibition of the PI3K/Akt pathway, indicating that the effect of bortezomib may be potentiated when the level of TGF-β is elevated, as is observed in the postoperative period.

Antifibrotic Activity of Bevacizumab on Human Tenon's Fibroblasts In Vitro

To evaluate the effect of the anti-VEGF-A monoclonal antibody bevacizumab on primary human Tenon's capsule fibroblasts (HTFs) in an in vitro model of wound healing. Fibroblasts were cultured in RPMI media, and bevacizumab was administered at a concentration ranging from 0.25 to 12.5 mg/mL. Fibroblast viability and cell death were assessed using the MTT colorimetric assay, lactate dehydrogenase assay, BrdU assay, and live/dead assay. Fibroblast contractility was assessed in floating collagen gels. Morphologic changes were assessed by transmission electron microscopy. Antifibrosis activities were compared with 5-fluorouracil. Bevacizumab induced a significant dose-related reduction of HTF cell number at 12.5 mg/mL at 72 hours (P < 0.05). Under serum-free conditions, bevacizumab induced significant fibroblast cell death at concentrations greater than 7.5 mg/mL (P < 0.05). Bevacizumab caused a moderate inhibition of fibroblast gel contraction from baseline (P < 0.05). Scanning electron microscopy revealed marked vacuolization in bevacizumab-treated fibroblasts. Bevacizumab disrupted fibroblast proliferation, inhibited collagen gel contraction ability, and induced fibroblast cell death at concentrations greater than 7.5 mg/mL in serum-free conditions. These results demonstrated that bevacizumab inhibited a number of fibrosis activities in culture. These activities may underpin the antifibrosis effect proposed in vivo.

Inducement effect of tetrandrine on the apoptosis of cultured human Tenon's capsule fibroblasts

Background Excessive conjunctival sear formation is a main cause of filtering surgical failure in glaucoma. It has been reported that the failure rate of filtering surgery is a tough problem in the research of glaucoma. Research showed that tetrandrine （Tet） suppress the proliferation of cultured human fibroblasts of Tenons capsule （TCFs） in vitro, but its possible mechanism is still unclear up to now. Objective The aim of this study is to investigate the inhibitory effects of Tet on the apoptosis of fibroblasts of Tenons capsule and mechanism. Methods The Tenon＇ s capsule was obtained from donor eyes of Zhongshan Eye Center Eye Bank for further use. Human Tenon＇ s capsule fibroblasts were cultured by explant culture method in mixed medium in vitro and the third to seventh generations of cells were collected for the experiment. The subcuhured cells were identified by morphology observation and Vimentin staining. The apoptosis of cultured fibroblasts in Tet-treated group and control group was studied by using TUNEL （TdT- mediated dUTP nick end ]abling,TUNEL）,flow cytometry （FCM） and transmission electron microscope. The cell number in different cellular cycle was calculated in Ted-treated group and control group. Results The cultured cells reached confluence in two weeks after cultured and presented the spindle or triangle shape with the radial-like or vortexiu-like arrangement . The cells showed the positive staining for Vimentin. Apoptosis changes of cultured cell and apoptosis bodies were seen under the transmission electron microscope. Apoptotic cell nuclei were observed in Tet group by TUNEL. FCM result showed that the cells at G0/G1 phase decreased by 22.2% ,and the cells at S and G2/M phases increased by 20. 53% and 1.6% in Ted-treated group. Significant differences in the numbers of cells in different cellular cycles and cell numbers of apoptosis were found between Tet-treated group and control group（ P = 0. 000）. Conclusion Tet can inhibit the proliferation of human TCFs by inducing apoptosis in vitro. Key words: tetrandrine; fibroblast cell; Tenon＇ s capsule; apoptosis; flow eytometry

The inhibitive effects of 5-fluorouracil-loaded polylactic acid nanoparticles on human Tenon's capsule fibroblast in vitro

To investigate the inhibitive effects of 5-fluorouracil-loaded polylactic acid nanoparticles (5-FU-PLA-NPs) on human Tenon's capsule fibroblasts in vitro. This paper was experimental study. MTT assay was performed to estimate the effects of 0.1 mg/L, 1.0 mg/L, 10.0 mg/L, 100.0 mg/L, 1000.0 mg/L unloaded polylactic acid nanoparticles (PLA-NPs) on fibroblasts proliferation on 48 h, 72 h. MTT assay was performed to estimate the effects of 0.1 mg/L, 1.0 mg/L, 10.0 mg/L, 100.0 mg/L, 1000.0 mg/L original 5-FU and 5-FU-PLA-NPs on fibroblasts' proliferation on 7 consecutive days respectively. The inhibitory rate of the two drugs against the fibroblasts was calculated. Cells were exposed to 100 mg/L original 5-FU and 5-FU-PLA-NPs respectively for 7 days. Semi-quantitative RT-PCR was used to observe the mRNA expression of type III procollagen at the 1st day, 5th day and 7th day. PLA-NPs had no cytotoxicity on the fibroblasts. Both 5-FU-PLA-NPs and original 5-FU could inhibit the proliferation of the fibroblasts and make the expression of type III procollagen mRNA lower in dose-dependent and time-dependent manner. The inhibitive effect of original 5-FU was more effective than 5-FU-PLA-NPs in the initial period, but the inhibitive effect of 5-FU-PLA-NPs was more effective than original 5-FU in long time. PLA has good biocompatibility and safety, and can be used as a carrier of ophthalmic drugs. 5-FU-PLA-NPs shows slow-releasing function. 5-FU-PLA-NPs can be proposed as a potential controlled and targeted ophthalmic delivery system for the treatment of antifibrosis after glaucoma filtering surgery.

Influence of ASODN to the human tenon's fibroblasts in expressing CTGF induced by transforming growth factor beta2

To investigate the effect of connective tissue growth factor's antisense oligonucleotides (ASODN) on the growth of human tenon' s capsule fibroblasts (HTF) induced by transforming growth factor beta2 (TGF-beta2) in vitro. It was a experimental study. HTF was collected from glaucoma patients and cultured. The 5-6 passage was used for experiments. The HTF induced by TGF-beta2 was divided into the following groups: N group: normal HTF; T group: HTF induced by TGF-beta2; A group: CTGF ASODN antisense:5'-TACTGGCGGCGGTCAT-3' encapsulated with liposome; S group: sense 5'-ATGACCGCCGCCAGTA-3' encapsulated with liposome; D group: HTF encapsulated with liposome only. The activity of HTF treated by different concentrations of liposome was detected using methylthianolyldiphenyl tetrazolium bromide (MT) colorimetry. The expression of CTGF was detected by reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry assays. The expression of fibronectin (Fn) was examined by Western blot and immunocytochemistry assays. Liposome-ASODN (A group) significantly (F=15.25, 204.88, 19.73, 90.00; P <0.05) inhibit the expression of CTGF and Fn in HTF induced by TGF-beta2 compared with S and D group. However, Liposome alone (T group) has no significant impact in HTF growth compared with T group (t = 0.90, 2.32, 0.75, 2.11; P > 0.05). CTGF-ASODN inhibits the CTGF and Fn expression of HTF induced by TGF-beta2, which may delay the formation of scar in glaucoma filtering surgery.

The Rho-Kinase Inhibitor H-1152P Suppresses the Wound-Healing Activities of Human Tenon’s Capsule Fibroblasts In Vitro

To analyze the role of Rho-kinase signaling in the wound-healing activities of human Tenon's capsule fibroblasts by using H-1152P, a potent inhibitor of this kinase, in vitro. The optimal concentration of H-1152P was determined by MTT test. Cell proliferation was measured by BrdU incorporation and Ki-67 immunostaining, whereas cell viability was investigated by ethidium homodimer-1 dye exclusion. The actin cytoskeleton organization was demonstrated by alpha-smooth muscle actin (SMA) immunostaining and Alexa 488-phalloidin staining. Cell migration was studied on restrained collagen gels and in a scratch-wound assay followed by Ki-67 and fibronectin immunostaining. The effect of H-1152P on contraction was analyzed in floating collagen gels populated with fibroblasts, which were subsequently processed for fibronectin immunostaining. The levels of adducin and the protein kinase A (PKA)-dependent phosphorylation of this protein were detected by immunoblot analysis, to rule out interference with PKA. Incorporation of BrdU and upregulation of Ki-67 were reduced by 80% to 90% in cells incubated with 10 microM of this inhibitor for 4 days (P < 0.01). H-1152P caused the disassembly of stress fibers in a dose-dependent manner without exerting toxic effects and without a considerable interference with the PKA-pathway. H-1152P also significantly suppressed cell migration 3- to 3.5-fold and the contraction of collagen lattices fivefold with a dose-dependent impairment in the assembly of the fibronectin network. These findings imply a role for Rho-kinase in the wound-healing activities of human Tenon's capsule fibroblasts and show the potential of H-1152P as a safe and specific means to suppress these events.

Synergistic effects of combined cytotoxic and apoptosis-inducing drugs on Tenon’s capsule fibroblasts in vitro and in vivo

Highly toxic antimetabolites have gained access to routine clinical use to modulate and reduce the amount of postoperative scarring following glaucomatous filtering procedures. It could be speculated that by combining two different antiproliferative substances with different mechanisms of action total amounts of the substances could be decreased and side effects reduced. Twenty-two substances were tested that had antiproliferative effects by acting cytotoxically, inhibiting growth factors, or inducing apoptosis. With combinations of each two substances, cell culture experiments using 3T3 and human Tenon's capsule fibroblasts were performed evaluating cell toxicity, proliferation and migration, the extent of free radicals, and the amount of apoptosis (TUNEL, electron microscopy). The five most potent combinations were used in an animal experiment with rabbits performing filtering procedures. The extent of episcleral scarring was evaluated by histopathology. The results of the various assays revealed consistently strong effects in 5 of the 462 combinations. Of these five combinations, two were highly effective in the rabbit model. Substances with strong effects when applied in combination included staurosporine, mitomycin, and CD95L. We found synergistic effects in assays that evaluated different aspects of cell function. The amount of scarring in an animal experiment was inhibited to a level comparable with a high single dose of mitomycin. Combination therapy of two antiproliferative acting substances may be a promising concept.