Human Corneal Fibroblasts Research Articles

Coenzyme Q10 and Vitamin E Regulate the Bioactivity of Human Corneal Fibroblast Cells.

Purpose: Corneal fibroblasts are involved in the wound healing of the cornea with proliferation, migration, and differentiation processes. Coenzyme Q10 (CoQ10) and vitamin E can enhance corneal wound healing when applied after a corneal lesion as an eye drop. Thus, this study was performed to determine the potential efficiency of a CoQ10 ophthalmical solution containing a CoQ10 and vitamin E D-α-tocopherol polyethylene glycol 1000 succinate (TPGS)-derived formulation in human corneal fibroblasts (HCFs) in vitro. Methods: Primary HCFs were obtained from cadaveric corneal tissue, and cell viability was determined using MTT assay at 24 and 72 h. Cell migration was evaluated using an in vitro wound healing assay, and mRNA expressions of collagen type I (COL-I), collagen type III (COL-III), lumican, hyaluronan, matrix metalloproteinase (MMP)-1, MMP-2, MMP-9, tissue inhibitors of MMP (TIMP)-1, TIMP-2, interleukin (IL)-1β, IL-6, IL-8, and IL-10 were assessed using reverse transcription polymerase chain reaction at 24 and 72 h. Results: At various concentrations of CoQ10 ophthalmical solution (CoQ10-os), cell viability and wound healing rates of HCFs increased compared with the control group. The expressions of COL-I, COL-III, lumican, and hyaluronan were increased by CoQ10-os, whereas those of MMP-1, MMP-2, MMP-9, TIMP-1, TIMP-2, and TIMP-3 were not affected by CoQ10-os at 24 and 72 h. In treating HCFs with a CoQ10-os medium, IL-1β, IL-6, and IL-8 decreased, whereas IL-10 was significantly increased in a time- and dose-dependent manner. Conclusions: The findings indicate that CoQ10 and vitamin E-TPGS are potent regulators of the bioactivity of HCFs, thus supporting their potential application as ophthalmical solutions in therapies aimed at the fast regeneration of damaged cornea tissues.

Generating a 3D Co-Culture Model of Human Corneal Fibroblasts and Neurons

Generating a 3D Co-Culture Model of Human Corneal Fibroblasts and Neurons

Proteomic Characterization of Corneal Epithelial and Stromal Cell-Derived Extracellular Vesicles.

Communication between the different layers of the cornea (epithelium and stroma) is a complex, yet crucial element in the corneal healing process. Upon corneal injury, it has been reported that the bi-directional cross talk between the epithelium and stroma via the vesicular secretome, namely, extracellular vesicles (EVs), can lead to accelerated wound closure upon injury. However, the distinct protein markers of EVs derived from human corneal epithelial (HCE) cells, keratocytes (HCKs), fibroblasts (HCFs), and myofibroblasts (HCMs) remain poorly understood. All EVs were enriched for CD81 and showed increased expression levels of ITGAV and FN1 in HCM-EVs compared to HCE- and HCF-EVs. All EVs were negative for GM130 and showed minimal differences in biophysical properties (particle concentration, median particle size, and zeta potential). At the proteomic level, we show that HCM-EVs are enriched with proteins associated with fibrosis pathways, such as COL6A1, COL6A2, MMP1, MMP2, TIMP1, and TIMP2, compared to HCE-, HCK-, and HCF-EVs. Interestingly, HCE-EVs express proteins involved with the EIF-2 signaling pathway (stress-induced signals to regulate mRNA translation), such as RPS21, RALB, EIF3H, RALA, and others, compared to HCK-, HCF-, and HCM-EVs. In this study, we isolated EVs from cell-conditioned media from HCE, HCKs, HCFs, and HCMs and characterized their biophysical and protein composition by Western blot, nanoparticle tracking analysis, and proteomics. This study supports the view that EVs from the corneal epithelium and stroma have a distinct molecular composition and may provide novel protein markers to distinguish the difference between HCE-, HCK-, HCF-, and HCM-EVs.

Corneal epithelial-stromal constructs to study differences associated with diabetes mellitus

Diabetes mellitus (DM) is a common metabolic disease associated with severe macrovascular and microvascular complications that influence nearly every tissue in the body, including the anterior and posterior segments of the eye. In the cornea, DM is associated with recurrent epithelial erosion and reduced wound-healing capacity, which increases the risk of corneal scarring. We previously developed a co-culture model of the cornea consisting of immortalized human corneal epithelial cells (hCE-TJ) overlaying a self-assembled stromal layer generated by human corneal fibroblasts (hCFs) over a 4-week period. In this study, we investigated epithelial-stromal constructs generated from hCFs derived from subjects with Type 1 (T1DM) or 2 diabetes (T2DM) compared to controls. We found that T2DM constructs exhibited a disrupted epithelium and a thicker, stratified stromal layer compared to controls or T1DM. Both T1DM and T2DM stromal constructs expressed lower expression of thrombospondin-1 in isolated extracellular vesicles (EVs) compared to controls with no significant difference observed in the presence of epithelial cells, suggesting that reduced provisional matrix secretion in the corneal stroma may be a factor that promotes delayed corneal wound healing in diabetes. The tetraspanins are established extracellular vesicle (EV) markers and include CD63, CD81, and CD9, and were highly expressed by EVs in all three cell types. Control corneal stromal fibroblasts produced more and larger EVs when compared to T1DM and T2DM hCF-derived EVs, supporting a role for altered cell-cell communication in the context of DM. Further characterization of EVs and their cargo is expected to aid in the development of targeted treatments to improve corneal wound healing.

Sodium butyrate alleviates lipopolysaccharide-induced inflammation through JAK/STAT signalling in primary human corneal fibroblasts

BackgroundBacterial keratitis is a common cause of blindness. Antibiotic treatment leads to the rapid release of lipopolysaccharide (LPS), which can activate corneal fibroblasts and cause persistent and excessive inflammatory responses. The anti-inflammatory drugs currently used to treat keratitis have serious side effects. Therefore, the ability of sodium butyrate (NaB), which can suppress the production of proinflammatory cytokines and promote the production of anti-inflammatory cytokines, to ameliorate keratitis was assessed in the present study. MethodsThe effect of NaB on the viability of primary human corneal fibroblasts was assayed with a CCK-8 kit. Cell migration was assessed by an in vitro scratch assay. Cell phenotypes were assessed by Western blotting and immunofluorescence staining. An antibody array was used to measure the production of proinflammatory cytokines and chemokines. ResultsAt 0–1 mM, NaB had no significant effect on cell viability, promoted the expression of the keratocyte marker keratocan and inhibited the fibroblast marker vimentin. Inhibition of cell migration was observed in the wound healing assay. By targeting the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signalling pathway, NaB decreased the levels of inflammation-related cytokines and chemokines whose expression was induced by LPS. ConclusionsNaB maintained the keratocyte phenotype, inhibited cell migration, and relieved LPS-induced inflammatory responses through the JAK/STAT signalling pathway.

Expression of matrix metalloproteinases and their inhibitors in corneal stromal fibroblasts and keratocytes from healthy and keratoconus corneas.

To examine the in-vitro expression of matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) in corneal stromal cells by distinguishing between fibroblasts and keratocytes of healthy and keratoconus (KC) corneas. Stromal cells were isolated from healthy and KC corneas (n = 8). A normal-glucose, serum-containing cell culture medium (NGSC-medium) was used for cultivation of healthy human corneal fibroblasts (HCFs) and KC human corneal fibroblasts (KC-HCFs). In order to obtain a keratocyte phenotype, the initial cultivation with NGSC-medium was changed to a low-glucose, serum-free cell culture medium for healthy (Keratocytes) and KC cells (KC-Keratocytes). Gene and protein expression of MMP-1, -2, -3, -7, -9 and TIMP-1, -2, -3 were measured by quantitative PCR and Enzyme-Linked Immunosorbent Assay (ELISA) from the cell culture supernatant. KC-HCFs demonstrated a lower mRNA gene expression for MMP-2 compared to HCFs. In contrast to their respective fibroblast groups (either HCFs or KC-HCFs), Keratocytes showed a higher mRNA gene expression of TIMP-3, whereas TIMP-1 mRNA gene expression was lower in Keratocytes and KC-Keratocytes. Protein analysis of the cell culture supernatant revealed lower concentrations of MMP-1 in KC-HCFs compared to HCFs. Compared to Keratocytes, TIMP-1 concentrations was lower in the cell culture supernatant of KC-Keratocytes. In HCFs and KC-HCFs, protein levels of MMP-1 and TIMP-1 were higher and MMP-2 was lower compared to Keratocytes and KC-Keratocytes, respectively. This study indicates an imbalance in MMP and TIMP expression between healthy and diseased cells. Furthermore, differences in the expression of MMPs and TIMPs exist between corneal fibroblasts and keratocytes, which could influence the specific proteolytic metabolism in-vivo and contribute to the progression of KC.

The Role of Vimentin in Human Corneal Fibroblast Spreading and Myofibroblast Transformation.

Vimentin has been reported to play diverse roles in cell processes such as spreading, migration, cell-matrix adhesion, and fibrotic transformation. Here, we assess how vimentin impacts cell spreading, morphology, and myofibroblast transformation of human corneal fibroblasts. Overall, although knockout (KO) of vimentin did not dramatically impact corneal fibroblast spreading and mechanical activity (traction force), cell elongation in response to PDGF was reduced in vimentin KO cells as compared to controls. Blocking vimentin polymerization using Withaferin had even more pronounced effects on cell spreading and also inhibited cell-induced matrix contraction. Furthermore, although absence of vimentin did not completely block TGFβ-induced myofibroblast transformation, the degree of transformation and amount of αSMA protein expression was reduced. Proteomics showed that vimentin KO cells cultured in TGFβ had a similar pattern of protein expression as controls. One exception included periostin, an ECM protein associated with wound healing and fibrosis in other cell types, which was highly expressed only in Vim KO cells. We also demonstrate for the first time that LRRC15, a protein previously associated with myofibroblast transformation of cancer-associated fibroblasts, is also expressed by corneal myofibroblasts. Interestingly, proteins associated with LRRC15 in other cell types, such as collagen, fibronectin, β1 integrin and α11 integrin, were also upregulated. Overall, our data show that vimentin impacts both corneal fibroblast spreading and myofibroblast transformation. We also identified novel proteins that may regulate corneal myofibroblast transformation in the presence and/or absence of vimentin.

Amelioration of Fibrosis via S1P Inhibition Is Regulated by Inactivation of TGF-β and SPL Pathways in the Human Cornea.

Human corneal fibrosis can lead to opacity and ultimately partial or complete vision loss. Currently, corneal transplantation is the only treatment for severe corneal fibrosis and comes with the risk of rejection and donor shortages. Sphingolipids (SPLs) are known to modulate fibrosis in various tissues and organs, including the cornea. We previously reported that SPLs are tightly related to both, transforming growth factor beta (TGF-β) signaling and corneal fibrogenesis. The aim of this study was to investigate the effects of sphingosine-1-phosphate (S1P) and S1P inhibition on specific TGF-β and SPL family members in corneal fibrosis. Healthy human corneal fibroblasts (HCFs) were isolated and cultured in EMEM + FBS + VitC (construct medium) on 3D transwells for 4 weeks. The following treatments were prepared in a construct medium: 0.1 ng/mL TGF-β1 (β1), 1 μM sphingosine-1-phosphate (S1P), and 5 μM Sphingosine kinase inhibitor 2 (I2). Five groups were tested: (1) control (no treatment); rescue groups; (2) β1/S1P; (3) β1/I2; prevention groups; (4) S1P/β1; and (5) I2/β1. Each treatment was administered for 2 weeks with one treatment and switched to another for 2 weeks. Using Western blot analysis, the 3D constructs were examined for the expression of fibrotic markers, SPL, and TGF-β signaling pathway members. Scratch assays from 2D cultures were also utilized to evaluate cell migration We observed reduced fibrotic expression and inactivation of latent TGF-β binding proteins (LTBPs), TGF-β receptors, Suppressor of Mothers Against Decapentaplegic homologs (SMADs), and SPL signaling following treatment with I2 prevention and rescue compared to S1P prevention and rescue, respectively. Furthermore, we observed increased cell migration following stimulation with I2 prevention and rescue groups, with decreased cell migration following stimulation with S1P prevention and rescue groups after 12 h and 18 h post-scratch. We have demonstrated that I2 treatment reduced fibrosis and modulated the inactivation of LTBPs, TGF-β receptors, SPLs, and the canonical downstream SMAD pathway. Further investigations are warranted in order to fully uncover the potential of utilizing SphK I2 as a novel therapy for corneal fibrosis.

Rose Bengal Photodynamic Therapy (RB-PDT) Modulates the Inflammatory Response in LPS-Stimulated Human Corneal Fibroblasts By Influencing NF-κB and p38 MAPK Signaling Pathways

Purpose To investigate the effect of rose bengal photodynamic therapy on lipopolysaccharide-induced inflammation in human corneal fibroblasts. Furthermore, to analyze potential involvement of the mitogen-activated protein kinase and nuclear factor kappa B signaling pathways in this process. Methods Human corneal fibroblast cultures underwent 0–2.0 µg/mL lipopolysaccharide treatment, and 24 h later rose bengal photodynamic therapy (0.001% RB, 565 nm wavelength illumination, 0.17 J/cm2 fluence). Interleukin-6, interleukin-8, intercellular adhesion molecule-1, interferon regulatory factor-3, interferon α2, and interferon β1 gene expressions were determined by quantitative PCR. Interleukin-6, interleukin-8, and C-C motif chemokine ligand-4 concentrations in the cell culture supernatant were measured by enzyme-linked immunosorbent assays and intercellular adhesion molecule-1 protein level in human corneal fibroblasts by western blot. In addition, the nuclear factor kappa B and mitogen-activated protein kinase signaling pathways were investigated by quantitative PCR and phosphorylation of nuclear factor kappa B p65 and p38 mitogen-activated protein kinase by western blot. Results Rose bengal photodynamic therapy in 2.0 µg/mL lipopolysaccharide-stimulated human corneal fibroblasts triggered interleukin-6 and interleukin-8 mRNA (p < .0001) and interleukin-6 protein increase (p < .0001), and downregulated intercellular adhesion molecule-1 expression (p < .001). C-C motif chemokine ligand-4, interferon regulatory factor-3, interferon α2, and interferon β1 expressions remained unchanged (p ≥ .2). Rose bengal photodynamic therapy increased IκB kinase subunit beta, nuclear factor kappa B p65, extracellular signal-regulated kinases-2, c-Jun amino terminal kinase, and p38 transcription (p ≤ .01), and triggered nuclear factor kappa B p65 and p38 mitogen-activated protein kinase phosphorylation (p ≤ .04) in lipopolysaccharide treated human corneal fibroblasts. Conclusion Rose bengal photodynamic therapy of lipopolysaccharide-stimulated human corneal fibroblasts can modify the inflammatory response by inducing interleukin-6 and interleukin-8 expression, and decreasing intercellular adhesion molecule-1 production. C-C motif chemokine ligand-4, interferon regulatory factor-3, and interferon α and β expressions are not affected by rose bengal photodynamic therapy in these cells. The underlying mechanisms may be associated with nuclear factor kappa B and p38 mitogen-activated protein kinase pathway activation.

Substance P promotes transforming growth factor-β-induced collagen synthesis in human corneal fibroblasts.

Corneal fibroblasts maintain homeostasis of the corneal stroma by mediating the synthesis and degradation of extracellular collagen, and these actions are promoted by transforming growth factor-β (TGF-β) and interleukin-1β (IL-1β), respectively. The cornea is densely innervated with sensory nerve fibers that are not only responsible for sensation but also required for physiological processes such as tear secretion and wound healing. Loss or dysfunction of corneal nerves thus impairs corneal epithelial wound healing and can lead to neurotrophic keratopathy. The sensory neurotransmitter substance P (SP) promotes corneal epithelial wound healing by enhancing the stimulatory effects of growth factors and fibronectin. We have now investigated the role of SP in collagen metabolism mediated by human corneal fibroblasts in culture. Although SP alone had no effect on collagen synthesis or degradation by these cells, it promoted the stimulatory effect of TGF-β on collagen type I synthesis without affecting that of IL-1β on the expression of matrix metalloproteinase-1. This effect of SP on TGF-β-induced collagen synthesis was accompanied by activation of p38 mitogen-activated protein kinase (MAPK) signaling and was attenuated by pharmacological inhibition of p38 or of the neurokinin-1 receptor. Our results thus implicate SP as a modulator of TGF-β-induced collagen type I synthesis by human corneal fibroblasts, and they suggest that loss of this function may contribute to the development of neurotrophic keratopathy.NEW & NOTEWORTHY This study investigates the role of substance P (SP) in collagen metabolism mediated by human corneal fibroblasts in culture. We found that, although SP alone had no effect on collagen synthesis or degradation by corneal fibroblasts, it promoted the stimulatory effect of transforming growth factor-β on collagen type I synthesis without affecting that of interleukin-1β on the expression of matrix metalloproteinase-1.

MiR-135a Mediates Mitochondrial Oxidative Respiratory Function through SIRT1 to Regulate Atrial Fibrosis

Introduction: This study aimed to explore the function of miR-135a in the progress of atrial fibrosis and the mechanism of miR-135a/SIRT1 (sirtuin 1) in human cardiac fibroblasts and mouse cardiac fibroblasts (MCFs) mediating the regulation of atrial fibrosis by mitochondrial oxidative respiration function. Methods: Using Ang II (angiotensin II) to induce fibrosis in HCFs (human corneal fibroblasts) and MCF (Michigan Cancer Foundation, MCF) cells in vitro, the miRNA-seq results of previous studies were validated. Proliferative and invasive ability of HCFs and MCFs was detected by Cell Counting Kit-8 assay (CCK-8) and scratch experiment after overexpressing miR-135a in HCFs and MCF cells. Protein and mRNA expression was tested using Western blot and qPCR. The target of miR-135a was verified as SIRT1 by a luciferase reporter assay and the activities of the mitochondrial respiratory enzyme complexes I, II, III, and IV were determined colorimetrically. The activities of malondialdehyde, reactive oxygen species, and superoxide dismutase in cells were detected with enzyme-linked immunosorbent assay (ELISA). Results: miR-135a expression was elevated in HCFs and MCFs cells in the Ang II group than control group. Overexpression of miR-135a could promote the proliferation, migration, oxidative stress, as well as fibrosis of cardiac fibroblasts and suppresses mitochondrial activity. In addition, we found SIRT1 was a target gene of miR-135a. What is more, the findings showed miR-135a promoted fibrosis in HCFs and MCFs cells acting through regulation of SIRT1. Conclusions: miR-135a mediates mitochondrial oxidative respiratory function through SIRT1 to regulate atrial fibrosis.

Viability of Transplanted De Novo Retinal Ganglion Cells in Human Donor Eyes Maintained Under Elevated Intraocular Pressure

Purpose: Glaucoma is a group of optic neuropathies characterized by visual field loss, classically due to increased intraocular pressure (IOP) and retinal ganglion cell (RGC) degeneration. Current treatment options reduce IOP, but RGC degeneration persists. De novoRGCs can be differentiated from reprogrammed human corneal fibroblasts and transplanted into the retina to potentially restore vision in patients with late-stage disease when most RGCs are irreversibly damaged. We investigate the survival of these human induced pluripotent stem cell (IPSC) derived RGCs after culturing them in human donor eyes under conditions of elevated and normal IOP using the ocular translaminar autonomous system (TAS) chamber.&#x0D; Methods: Human iPSCs were generated by reprogramming human donor corneal fibroblasts using Sendai viral vectors with Yamanaka factors. These iPSCs were then differentiated into retinal organoids from which RGCs were obtained. The RGCs were transduced with AAV2-GFP and transplanted into donor human eyes obtained from control individuals. They were pressurized for approximately 5 days, with the left eye maintained at normal IOP and right eye at elevated IOP. Viability was measured by expression levels of pro-survival pathways via qRTPCR, immunohistochemistry staining, and electroretinography for retinal function (ERG).&#x0D; Results: We successfully transplanted human RGCs into human donor eyes and visualized them after GFP transduction. We maintained a pressure differential between the two eyes for approximately 5 days using the TAS model. Differential expression of survival, inflammatory and apoptotic genes was identified between normal and high IOP. We identified retinal function changes under normal and high IOP after RGC transplantation.&#x0D; Conclusions: Human iPSC derived RGCs provide a potential strategy to overcome vision loss in patients with diseases that damage RGCs such as glaucoma, Parkinson’s, Alzheimer's, multiple sclerosis, and traumatic optic neuropathy. Future investigation would involve integration of transplanted RGCs and directing their axons towards visual centers in the brain.

Short‐term effect of rose bengal photodynamic therapy on collagen I, collagen V, nuclear factor kappa B, lysyl oxydase, transforming growth factor beta and interleukin 6 expression of human corneal fibroblasts, in vitro

Aims/Purpose: To investigate collagen I, collagen V, nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB), lysyl oxidase (LOX), transforming growth factor β (TGF‐β) and interleukin‐6 (IL‐6) expression in healthy human corneal fibroblasts (HCFs) and keratoconus fibroblasts (KC‐HCFs), 24 h after rose bengal photodynamic therapy (RB‐PDT).Methods: HCFs were isolated from healthy human corneal donors (n = 5) and KC‐HCFs from elective penetrating keratoplasties (n = 5). Both cell cultures underwent RB‐PDT (0.001% rose bengal concentration, 0.17 J/cm2 fluence) and 24 h later collagen I, collagen V, NF‐κB, LOX, TGF‐β and IL‐6 mRNA and protein expression has been determined using qPCR and Western blot, compared to untreated cultures. IL‐6 concentration in the cell culture supernatant has been determined by ELISA.Results: TGF‐β mRNA expression was significantly lower (p = 0.02) and IL‐6 mRNA expression was significantly higher in HCFs 24 h after treatment (p = 0.01), than in controls. COL1A1, COL5A1 and TGF‐β mRNA expression was significantly lower (p = 0.048; p = 0.02 and p = 0.02) and IL‐6 mRNA expression was significantly higher (p = 0.02) in KC‐HCFs 24 h after RB‐PDT, than in untreated KC‐HCFs. TGF‐β protein expression in HCFs was significantly higher 24 h after treatment, than in controls (p = 0.03). IL‐6 protein concentration in the HCF and KC‐HCF culture supernatant was significantly higher 24 h after treatment, than in controls (p = 0.02; p = 0.03). Nevertheless, collagen I, collagen V protein, NF‐κB and LOX mRNA and protein expression did not differ significantly between any of the RB‐PDT treated and untreated groups.Conclusions: In conclusion, our study demonstrates that RB‐PDT reduces collagen I, collagen V and TGF‐β mRNA expression, while increasing IL‐6 mRNA and protein expression in KC‐HCFs. In HCFs, RB‐PDT increases TGF‐β and IL‐6 protein level after 24 h. These observations may provide a basis for future research in this field.

Human corneal epithelial cell and fibroblast migration and growth factor secretion after rose bengal photodynamic therapy (RB-PDT) and the effect of conditioned medium.

To investigate human corneal epithelial cell and fibroblast migration and growth factor secretion after rose bengal photodynamic therapy (RB-PDT) and the effect of conditioned medium (CM). A human corneal epithelial cell line (HCE-T), human corneal fibroblasts (HCF) and keratoconus fibroblasts (KC-HCF) have been used. Twenty-four hours after RB-PDT (0.001% RB concentration, 565 nm wavelength illumination, 0.17 J/cm2 fluence) cell migration rate using scratch assay and growth factor concentrations in the cell culture supernatant using ELISA have been determined. In addition, the effect of CM has been observed. RB-PDT significantly reduced migration rate in all cell types, compared to controls (p≤0.02). Migration rate of HCE-T cultures without RB-PDT (untreated) was significantly higher using HCF CM after RB-PDT, than using HCF CM without RB-PDT (p<0.01). Similarly, untreated HCF displayed a significantly increased migration rate with HCE-T CM after RB-PDT, compared to HCE-T CM without treatment (p<0.01). Furthermore, illumination alone and RB-PDT significantly decreased keratinocyte growth factor (KGF) concentration in HCF and KC-HCF supernatant, and RB-PDT significantly decreased soluble N-Cadherin (SN-Cad) concentration in HCF supernatant, compared to controls (p<0.01 for all). In HCE-T CM, RB-PDT increased hepatocyte growth factor (HGF) and basic fibroblast growth factor (FGFb) concentration (p≤0.02), while decreasing transforming growth factor β (TGF-β) concentration (p<0.01). FGFb concentration increased (p<0.0001) and TGF-β concentration decreased (p<0.0001) in HCF CM, by RB-PDT. Epidermal growth factor (EGF), HGF, and TGF-β concentration decreased (p≤0.03) and FGFb concentration increased (p<0.01) in KC-HCF CM, using RB-PDT. HCE-T, HCF and KC-HCF migration rate is reduced 24 hours after RB-PDT. In contrast, HCE-T migration is enhanced using HCF CM after RB-PDT, and HCF migration rate is increased through HCE-T CM following RB-PDT. Modulation of EGF, KGF, HGF, FGFb, TGF-β and N-Cadherin secretion through RB-PDT may play an important role in corneal wound healing.

Effect of Silica in the Manufacture of Autologous Serum Eye Drops on Corneal Stromal Cells.

The aim of this study was to evaluate the effect of serum clot activator, silica (SiO 2 ), which may be used for making autologous serum eye drops, on human corneal fibroblasts. Cultured human corneal fibroblasts were exposed to 10%, 20%, and 30% silica for 1, 6, and 24 hours; methyl thiazolyl tetrazolium-based colorimetric assay was performed to determine the survival rate of fibroblasts and lactate dehydrogenase leakage assay to assess the cytotoxicity. The apoptotic response was evaluated by flow cytometric analysis and fluorescence staining with Annexin V and propidium iodide. Cellular morphology was evaluated by inverted phase-contrast light microscopy and electron microscopy. The survival rate of human corneal fibroblasts and cytotoxicity showed both dose-dependent and time-dependent responses. The fluorescent micrograph and flow cytometry showed that as the exposure time increased, more cells underwent apoptosis or necrosis after treatment with 30% silica. When observed with light and electron microscopy, the number of corneal fibroblasts decreased and they were more detached from the dish. In addition, damaged corneal fibroblasts showed degenerative changes after exposure to 30% silica. Silica showed dose-dependent and time-dependent toxicity in human corneal fibroblasts. It is safer to keep the blood in tubes without a clot activator when manufacturing autologous serum eye drops to prevent possible corneal cytotoxicity.

Cell sheet-based approach to study the diabetic corneal stroma

Prolonged hyperglycemia during diabetes mellitus (DM) is associated with severe complications that may affect both the anterior and posterior ocular segments, leading to impaired vision or blindness. The cornea is a vital part of the eye that has a dual role as a protective transparent barrier and as a major refractive structure and is likewise negatively affected by hyperglycemia in DM. Understanding the cellular and molecular mechanisms underlying the phenotypic changes associated with DM is critical to developing targeted therapies to promote tissue integrity. In this proof-of-concept study, we applied a cell sheet-based approach to generate stacked constructs of physiological corneal thickness using primary human corneal fibroblasts isolated from cadaveric control (healthy), Type 1 DM and Type 2 DM corneal tissues. Self-assembled corneal stromal sheets were generated after 2 weeks in culture, isolated, and subsequently assembled to create stacked constructs, which were evaluated using transmission electron microscopy. Analysis of gene expression patterns revealed significant downregulation of fibrotic markers, α-smooth muscle actin, and collagen type 3, with stacking in Type 2 DM constructs when compared to controls. IGF1 expression was significantly upregulated in Type 2 DM constructs compared to controls with a significant reduction induced by stacking. This study describes the development of a thicker, self-assembled corneal stromal construct as a platform to evaluate phenotypic differences associated with DM-derived corneal fibroblasts and enable the development of targeted therapeutics to promote corneal integrity.

Short-Term Effect of Rose Bengal Photodynamic Therapy (RB-PDT) on Collagen I, Collagen V, NF-κB, LOX, TGF-β and IL-6 Expression of Human Corneal Fibroblasts, In Vitro

Purpose To investigate collagen I, collagen V, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), lysyl oxidase (LOX), transforming growth factor β1 (TGF-β1) and interleukin-6 (IL-6) expression in healthy and keratoconus human corneal fibroblasts (HCFs and KC-HCFs), 24 h after Rose Bengal photodynamic therapy (RB-PDT). Methods HCFs were isolated from healthy human corneal donors (n = 5) and KC-HCFs from elective penetrating keratoplasties (n = 5). Both cell cultures underwent RB-PDT (0.001% RB concentration, 0.17 J/cm2 fluence) and 24 h later collagen I, collagen V, NF-κB, LOX, TGF-β1 and IL-6 mRNA and protein expression have been determined using qPCR and Western blot, IL-6 concentration in the cell culture supernatant by ELISA. Results TGF-β1 mRNA expression was significantly lower (p = 0.02) and IL-6 mRNA expression was significantly higher in RB-PDT treated HCFs (p = 0.01), than in HCF controls. COL1A1, COL5A1 and TGF-β1 mRNA expression was significantly lower (p = 0.04; p = 0.02 and p = 0.003) and IL-6 mRNA expression was significantly higher (p = 0.02) in treated KC-HCFs, than in KC-HCF controls. TGF-β1 protein expression in treated HCFs was significantly higher than in HCF controls (p = 0.04). IL-6 protein concentration in the HCF and KC-HCF culture supernatant after RB-PDT was significantly higher than in controls (p = 0.02; p = 0.01). No other analyzed mRNA and protein expression differed significantly between the RB-PDT treated and untreated groups. Conclusions Our study demonstrates that RB-PDT reduces collagen I, collagen V and TGF-β1 mRNA expression, while increasing IL-6 mRNA and protein expression in KC-HCFs. In HCFs, RB-PDT increases TGF-β1 and IL-6 protein level after 24 h.

A negative feedback loop centered on SMAD3 expression in transforming growth factor β1-induced corneal myofibroblast differentiation

SMAD3 downregulation is documented in transforming growth factor β1 (TGF-β1)-induced corneal fibroblasts differentiation to myofibroblasts (“fibroTOmyoDiff”) or corneal wound healing. However, the exact regulatory mechanism of TGF-β1/SMAD3 pathway in this context remains unclear. Here, we investigated the role and related mechanism of SMAD3 down-regulation in TGF-β1-induced human corneal fibroTOmyoDiff. By detecting expression changes of SMAD family during this process, we demonstrated that SMAD3 protein expression was dramatically decreased in the process and the decrease occurred mainly in SMAD3 gene transcription. Furthermore, SMAD3 overexpression using lentivirus infection and knockdown using sgRNA lentivirus infection or siRNAs revealed that SMAD3 overexpression enhanced TGF-β1-induced corneal fibroTOmyoDiff and vice versa. In addition, specific siRNAs and inhibitors targeting particular signaling pathway were used to figure out the intracellular signaling pathway regulating SMAD3, and the result showed that the decease of SMAD3 induced by TGF-β1 stimulation in human corneal fibroblasts (HCFs) was strikingly prevented by SMAD4 knockdown or p38 signaling inhibitor SB203580 treatment. Collectively, these results demonstrate that, in TGF-β1 induced corneal fibroTOmyoDiff, down-regulation of SMAD3 expression regulated by SMAD4 and p38 signaling pathways forms a negative feedback loop of TGFβ signaling to avoid excessive activation of the signaling, which suggest that SMAD3 may be a key target for corneal fibrosis treatment.

TGF-β2 Induces Epithelial-Mesenchymal Transitions in 2D Planer and 3D Spheroids of the Human Corneal Stroma Fibroblasts in Different Manners.

To examine the epithelial-mesenchymal transition (EMT) that is induced on the human corneal stroma, two- and three-dimensional (2D and 3D) cultures of human corneal stroma fibroblasts (HCSFs) were used. In this study, HCSF 2D monolayers and 3D spheroids were characterized by (1) scanning electron microscopy (SEM), (2) trans-endothelial electrical resistance (TEER) measurements and fluorescein isothiocyanate (FITC)-dextran permeability, (3) cellular metabolic measurements, (4) the physical properties of 3D HCSF spheroids, and (5) the extracellular matrix (ECM) molecule gene expressions, including collagen (COL) 1, 4 and 6, and fibronectin (FN), a tissue inhibitor of metalloproteinase (TIMP) 1-4, matrix metalloproteinase (MMP) 2, 3, 9 and 14, and several endoplasmic reticulum (ER) stress-related factors. In the 2D HCSFs, TGF-β2 concentration-dependently generated (1) a considerable increase in ECM deposits revealed by SEM, (2) an increase in TEER values and a decrease in FITC-dextran permeability, (3) increases in both mitochondrial and glycolytic functions, and a substantial upregulation of COL1, COL4, FN, αSMA, TIMP1, TIMP, and most ER stress-related genes and the downregulation of COL6 and MMP3. In the case of 3D spheroids, TGF-β2 induced the downsizing and stiffening of 3D spheroids and the upregulation of COL6, MMP14, and most ER stress-related genes. These findings suggest that TGF-β2 significantly induced a number of EMT-associated biological events including planar proliferation, cellular metabolic functions, and the production of ECM molecules in the 2D cultured HCSF cells, but these effects were significantly less pronounced in the case of 3D HCSF spheroids.

Novel Correlation between TGF-β1/-β3 and Hormone Receptors in the Human Corneal Stroma.

This study investigated the interplay between transforming growth factor beta (TGF-β1/T1 and TGF-β3/T3), and sex hormone receptors using our 3D in vitro cornea stroma model. Primary human corneal fibroblasts (HCFs) from healthy donors were plated in transwells at 106 cells/well and cultured for four weeks. HCFs were supplemented with stable vitamin C (VitC) and stimulated with T1 or T3. 3D construct proteins were analyzed for the androgen receptor (AR), progesterone receptor (PR), estrogen receptor alpha (ERα) and beta (ERβ), luteinizing hormone receptor (LHR), follicle-stimulating hormone receptor (FSHR), gonadotropin-releasing hormone receptor (GnRHR), KiSS1-derived peptide receptor (KiSS1R/GPR54), and follicle-stimulating hormone subunit beta (FSH-B). In female constructs, T1 significantly upregulated AR, PR, ERα, FSHR, GnRHR, and KiSS1R. In male constructs, T1 significantly downregulated FSHR and FSH-B and significantly upregulated ERα, ERβ, and GnRHR. T3 caused significant upregulation in expressions PR, ERα, ERβ, LHR, FSHR, and GNRHR in female constructs, and significant downregulation of AR, ERα, and FSHR in male constructs. Semi-quantitative Western blot findings present the interplay between sex hormone receptors and TGF-β isoforms in the corneal stroma, which is influenced by sex as a biological variable (SABV). Additional studies are warranted to fully delineate their interactions and signaling mechanisms.