All-trans-retinoic acid inhibition of transforming growth factor-β-induced collagen gel contraction mediated by human Tenon fibroblasts: role of matrix metalloproteinases

Gene expression profiles in COVID-19-associated tracheal stenosis indicate persistent anti-viral response and dysregulated retinol metabolism

INTRODUCTION

Coronavirus disease 2019 (COVID-19)-associated tracheal stenosis (COATS) may occur as a result of prolonged intubation during COVID-19 infection. We aimed to investigate patterns of gene expression in the tracheal granulation tissue of patients with COATS, leverage gene expression data to identify dysregulated cellular pathways and processes, and discuss potential therapeutic options based on the identified gene expression profiles.

METHODS

Adult patients (age ≥ 18 years) presenting to clinics for management of severe, recalcitrant COATS were included in this study. RNA sequencing and differential gene expression analysis was performed with transcriptomic data for normal tracheal tissue being used as a control. The top ten most highly upregulated and downregulated genes were identified. For each of these pathologically dysregulated genes, we identified key cellular pathways and processes they are involved in using Gene Ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) applied via Database for Annotation, Visualization, and Integrated Discovery (DAVID).

RESULTS

Two women, aged 36 years and 37 years, were included. The profile of dysregulated genes indicated a cellular response consistent with viral infection (CXCL11, PI15, CCL8, DEFB103A, IFI6, ACOD1, and DEFB4A) and hyperproliferation/hypergranulation (MMP3, CASP14 and HAS1), while downregulated pathways included retinol metabolism (ALDH1A2, RBP1, RBP4, CRABP1 and CRABP2).

CONCLUSION

Gene expression changes consistent with persistent viral infection and dysregulated retinol metabolism may promote tracheal hypergranulation and hyperproliferation leading to COATS. Given the presence of existing literature highlighting retinoic acid's ability to favorably regulate these genes, improve cell-cell adhesion, and decrease overall disease severity in COVID-19, future studies must evaluate its utility for adjunctive management of COATS in animal models and clinical settings.

All Trans-Retinoic Acids Facilitate the Remodeling of 2D and 3D Cultured Human Conjunctival Fibroblasts

Vitamin A derivative, all-trans-retinoic acid (ATRA), is known to be a potent regulator of the growth and differentiation of various types of cells. In the present study, the unidentified effects of ATRA on superficial and vertical spreading conjunctival scarring were examined. The study involved the use of two-dimensional (2D) and three-dimensional (3D) cultures of human conjunctival fibroblast (HconF) cells in the presence or absence of TGF-β2. The effects of ATRA (1 μM) on superficial or vertical spreading conjunctival scarring were evaluated by the barrier function by trans-endothelial electrical resistance (TEER) and FITC dextran permeability measurements and real-time metabolic analysis, as well as the physical properties, namely, the size and stiffness, of 3D spheroids, respectively. In addition, the expressions of several related molecules, including extracellular matrix (ECM) molecules, ECM modulators including a tissue inhibitor of metalloproteinases (TIMPs), matrix metalloproteinases (MMPs), and ER stress-related factors, were examined. ATRA significantly induced (1) an increase in TEER values and a decrease in FITC dextran permeability, respectively, in the 2D monolayers, and (2) relatively and substantially increased the size and stiffness, respectively, of the 3D spheroids. These ATRA-induced effects were further enhanced in the TGF-β2-treated cells, whereas the TGF-β2-induced enhancement in glycolytic capacity was canceled by the presence of ATRA. Consistent with these physical and morphological effects, the mRNA expressions of several molecules were significantly but differently induced between 2D and 3D cultures by ATRA, although the presence of TGF-β2 did not substantially affect these gene expression levels. The findings reported in this study indicate that ATRA may exacerbate both superficial and vertical conjunctival fibrosis spreading independently of TGF-β2-induced changes.

Promotion of conjunctival fibroblast-mediated collagen gel contraction by mast cells through up-regulation of matrix metalloproteinase release and activation

Mast cells and conjunctival fibroblasts contribute to conjunctival wound healing and allergic ocular inflammation. The number of mast cells in the conjunctiva is increased in individuals with cicatricial fibrosis-causing ocular surface diseases and after glaucoma filtering surgery, suggesting that these cells may contribute to the scarring observed after such surgery. We studied the potential mechanism of fibroblast-mast cell interaction in the healing of conjunctival wounds using a three-dimensional collagen gel culture system. We found that mast cells derived from the bone marrow of mice embedded in a collagen gel did not induce gel contraction. However, an increase in mast cells was associated with increased collagen gel contraction mediated by mouse conjunctival fibroblasts. The extent of collagen degradation was not affected by the co-culture of mast cells and conjunctival fibroblasts. Gelatin zymography disclosed that mast cells increased the amounts of both the pro form of matrix metalloproteinase (MMP)-9 and the active form of MMP-2 in supernatants of conjunctival fibroblast cultures. Furthermore, the potentiating effect of mast cells on contraction of the collagen gel through conjunctival fibroblasts was attenuated by the addition of a synthetic MMP inhibitor. Thus, current results suggest that mast cells accelerate the conjunctival fibroblast-dependent contraction of collagen gel by increasing the release as well as activation of MMPs. Therefore, the interaction between mast cells and conjunctival fibroblasts may contribute to conjunctival scar formation after glaucoma filtering surgery.

Comprehensive microRNA and transcriptomic profiling of rheumatoid arthritis monocytes: role of microRNA-146b in proinflammatory progression

OBJECTIVE

To explore global miRNA and transcriptomic profiling of monocytes from rheumatoid arthritis (RA) patients compared with healthy controls (HC) to predict which aberrantly expressed microRNA (miRNA) can negatively modulate inflammatory molecules.

METHODS

Using next generation sequencing (NGS), we have performed simultaneous global analysis of miRNA (miRNA-seq) and transcriptome (RNA-seq) of monocytes from RA patients, HC. Global analysis of miRNA of systemic sclerosis (SSc) monocytes was also performed. Following differential analysis and negative correlation, miRNA-RNA pairs were selected.

RESULTS

We found that 20 specific miRNA candidates are predicted to silence inflammatory mediators, out of 191 significantly changed miRNAs in RA monocytes. Based on the highest scoring in terms of negative correlation (r=-0.97, p= 1.75e-07, FDR = 0.04) and the number of seeds in miRNA responsible for negative regulation, we selected miRNA-146b and its target gene anti-inflammatory retinoic acid receptor alpha (RARA). Similarly, to NGS, qPCR analysis also confirmed negative correlation between miRNA-146b and RARA expression (r= -0.45, p= 0.04,). Additionally, miRNA-146b expression in RA monocytes significantly correlated with clinical parameters including disease activity score-28 for RA with c-reactive protein (DAS28-CRP) and erythrocyte sedimentation rate (DAS28-ESR). Whereas overexpression of miRNA-146b was able to functionally reduce RARA expression in THP-1 monocytic cell line. Finally, circulating miRNA-146b expression in sera and synovial fluids was significantly elevated in RA patients.

CONCLUSIONS

Overall, in this study we have identified a new miRNA-146b candidate which is predicted to negatively regulate anti-inflammatory RARA transcript, whereas circulating miRNA-146b level can be used as a biomarker predicting proinflammatory RA progression and disease activity.

N-acetyl cysteine-loaded graphene oxide-collagen hybrid membrane for scarless wound healing

Wound dressings composed of natural polymers, such as type I collagen, possess good biocompatibility, water holding capacity, air permeability, and degradability, and can be used in wound repair. However, due to the persistent oxidative stress in the wound area, the migration and proliferation of fibroblasts might be suppressed, leading to poor healing. Thus, collagen-containing scaffolds are not suitable for accelerated wound healing. Antioxidant N-acetyl cysteine (NAC) is known to reduce the reactive oxygen species (ROS) and has been widely used in the clinic. Theoretically, the carboxyl group of NAC allows loading of graphene oxide (GO) for sustained release and may also enhance the mechanical properties of the collagen scaffold, making it a better wound-dressing material. Herein, we demonstrated an innovative approach for a potential skin-regenerating hybrid membrane using GO incorporated with collagen I and NAC (N-Col-GO) capable of continuously releasing antioxidant NAC. Methods: The mechanical stability, water holding capacity, and biocompatibility of the N-Col-GO hybrid membrane were measured in vitro. A 20 mm rat full-skin defect model was created to evaluate the repair efficiency of the N-Col-GO hybrid membrane. The vascularization and scar-related genes in the wound area were also examined. Results: Compared to the Col only scaffold, N-Col-GO hybrid membrane exhibited a better mechanical property, stronger water retention capacity, and slower NAC release ability, which likely promote fibroblast migration and proliferation. Treatment with the N-Col-GO hybrid membrane in the rat wound model showed complete healing 14 days after application which was 22% faster than the control group. HE and Masson staining confirmed faster collagen deposition and better epithelization, while CD31 staining revealed a noticeable increase of vascularization. Furthermore, Rt-PCR demonstrated decreased mRNA expression of profibrotic and overexpression of anti-fibrotic factors indicative of the anti-scar effect. Conclusion: These findings suggest that N-Col-GO drug release hybrid membrane serves as a better platform for scarless skin regeneration.

Effects of the isothiocyanate sulforaphane on TGF-β1-induced rat cardiac fibroblast activation and extracellular matrix interactions

An important step in many pathological conditions, particularly tissue and organ fibrosis, is the conversion of relatively quiescent cells into active myofibroblasts. These are highly specialized cells that participate in normal wound healing but also contribute to pathogenesis. These cells possess characteristics of smooth muscle cells and fibroblasts, have enhanced synthetic activity secreting abundant extracellular matrix components, cytokines, and growth factors, and are capable of generating contractile force. As such, these cells have become potential therapeutic targets in a number of disease settings. Transforming growth factor β (TGF-β) is a potent stimulus of fibrosis and myofibroblast formation and likewise is an important therapeutic target in several disease conditions. The plant-derived isothiocyanate sulforaphane has been shown to have protective effects in several pathological models including diabetic cardiomyopathy, carcinogenesis, and fibrosis. These studies suggest that sulforaphane may be an attractive preventive agent against disease progression, particularly in conditions involving alterations of the extracellular matrix and activation of myofibroblasts. However, few studies have evaluated the effects of sulforaphane on cardiac fibroblast activation and their interactions with the extracellular matrix. The present studies were carried out to determine the potential effects of sulforaphane on the conversion of quiescent cardiac fibroblasts to an activated myofibroblast phenotype and associated alterations in signaling, expression of extracellular matrix receptors, and cellular physiology following stimulation with TGF-β1. These studies demonstrate that sulforaphane attenuates TGF-β1-induced myofibroblast formation and contractile activity. Sulforaphane also reduces expression of collagen-binding integrins and inhibits canonical and noncanonical TGF-β signaling pathways.

Tranilast inhibits TGF-β-induced collagen gel contraction mediated by human corneal fibroblasts

AIM

To determine if tranilast affects human corneal fibroblast (HCFs) contraction.

METHODS

HCFs cultured in a three-dimensional type I collagen gel were treated with or without transforming growth factor beta (TGF-β) or tranilast. Gel diameter was measured as an indicator for collagen contraction. Immunoblot was performed to evaluate myosin light chain (MLC) and paxillin phosphorylation. Confocal microscopy was employed to examine the focal adhesions and actin stress fiber formation. Immunoblot analysis and gelatin zymography were performed to detect tissue inhibitors of metalloproteinases and matrix metalloproteinases (MMPs) in supernatant.

RESULTS

The inhibitory effect of tranilast on HCFs-mediated collagen gel contraction induced by TGF-β was dose-dependent. The significant effect of tranilast was started from 100 µmol/L and maximized at 300 µmol/L. The peak effect of 300 µmol/L tranilast also relied on the duration of treatment, which showed statistical significance from day 2. TGF-β-induced paxillin and MLC phosphorylation, stress fiber formation, focal adhesions, and MMP-1, MMP-2, and MMP-3 secretion in HCFs were also inhibited by tranilast.

CONCLUSION

Tranilast suppresses the HCFs-cultured collagen gel contraction induced by TGF-β. It attenuates actin stress fibers formation, focal adhesions, and the secretion of MMPs, with these actions likely contributing to the inhibitory effect on HCF contractility. By attenuating the contractility of corneal fibroblasts, tranilast treatment may inhibit corneal scarring.

Modulation of Fibroblasts in Conjunctival Wound Healing

Modulating conjunctival wound healing has the potential to improve outcomes after glaucoma filtration surgery and for several ocular disorders, including ocular cicatrial pemphigoid, vernal keratoconjunctivitis, and pterygium. Although anti-inflammatories and antimetabolites have been used with success, these nonspecific agents are not without their complications. The search for novel and more targeted means to control conjunctival fibrosis without such limitations has brought much attention to the regulation of fibroblast proliferation, differentiation, extracellular matrix production, and apoptosis. This review provides an update on where we stand with current antifibrotic agents and outlines the strategies that novel agents use, as they evolve from the bench to the bedside.

The selective cysteinyl leukotriene receptor 1 (CysLT1R) antagonist montelukast regulates extracellular matrix remodeling

Scar formation after filtration surgery of glaucoma is mainly caused by excessive synthesis of new extracellular matrix (ECM) and contraction of subconjunctival tissue mediated by human Tenon fibroblasts (HTFs) and the transforming growth factor (TGF-β1). Montelukast, a potent and specific cysteinyl leukotriene receptor 1 (cysLT1R) antagonist, is a licensed drug clinically used for the treatment of bronchial asthma. In this study, we investigated the effects of montelukast on the contractility of HTFs cultured in a three-dimensional collagen gel. We found that cysLT1R was expressed in HTFs. Interestingly, the expression of cysLT1R was increased in response to TGF-β1 in a dose dependent manner, suggesting its potential role in TGF-β1 induced fibrosis. Importantly, we found that montelukast inhibited TGF-β1-induced collagen gel contraction mediated by HTFs in a concentration- and time-dependent manner. In addition, TGF-β1-induced expression of MMP-1 and MMP-3, generation of fibronectin and type I collagen production, focal adhesion kinase (FAK) and paxillin phosphorylation in HTFs were also ameliorated by montelukast in a dose dependent manner. These results suggested that montelukast might provide therapeutic possibilities for inhibition of scar formation after such surgery.

Inhibition of Zymosan-Induced Inflammatory Factors Expression by ATRA Nanostructured Lipid Carriers

Purpose. The study aimed to evaluate the effect of all-trans retinoic acid-loaded nanostructured lipid carriers (ATRA-NLCs) on the zymosan-induced expression of the cytokines IL-4, IL-10, and IFN-γ and the matrix metalloproteinases/tissue inhibitor of metalloproteinases (MMPs/TIMPs) and TLR₂ in rabbit corneal fibroblasts (RCFs). Methods. ATRA-NLCs were prepared by emulsification. RCFs were isolated and harvested after four to seven passages in monolayer culture. Cytokine release (IL-4, IL-10, and IFN-γ) induced by zymosan was analyzed by cytokine release assay, reverse transcription, and real-time polymerase chain reaction (RT-PCR) analysis detection. MMP-1, MMP-3, and MMP-13, TIMP-1 and TIMP-2, and TLR2 expression were analyzed by immunoblotting. Results. ATRA-NLCs were resistant to light and physically stable, and the average size of the ATRA-NLCs was 200 nm. ATRA-NLCs increased the zymosan-induced release of IL-4 and IL-10 and decreased the release of IFN-γ by RCFs. ATRA-NLCs decreased the levels of TLR2 and MMPs/TIMPs above. Conclusions. ATRA may be a potent anti-inflammatory agent for the therapy of fungal keratitis (FK).