Inhibited effect of an RGD peptide hydrogel on the expression of β1-integrin, FAK, and Akt in Tenon's capsule fibroblasts

Characteristics of Mitomycin C-Loaded Peptide Hydrogel In Vitro and Antiscarring Effects in Rat Ocular Injury Model

Purpose: To investigate the characteristics of sustained drug release systems established by an arginine-glycine-aspartic acid (RGD) peptide hydrogel and mitomycin C (MMC) in vitro, and verify their antiscar effects in rat ocular injury model. Methods: Low, medium, and high loading doses of MMC were added to 5 mL 0.25%, 0.5%, and 1% wt RGD peptide hydrogel, respectively, to prepare 9 ratios of MMC-RGD systems. Drug release characteristics of the systems in phosphate-buffered saline solution were investigated by plotting the drug release curves and fitting them with mathematical models in OriginPro8.0 software. Appropriate ratios of MMC-RGD systems were selected as treatment in rat ocular injury model. Scar formation was observed by Masson staining and immunohistochemical staining with alpha-smooth muscle actin (α-SMA) and fibronectin (FN). Results: Nine ratios of MMC-RGD systems could release drug slowly. The maximum drug release proportions of all systems were >80%, and the time to maximum release proportions statistically prolonged with the increase of drug loading. Fitting with mathematical models indicated that the mechanisms of drug release were mainly Fick diffusion at early stage and Anomalous Transport at later stage. Systems of 1% wt RGD hydrogel were evaluated in animal experiments, which could inhibit hyperplasia of collagen and expression of α-SMA and FN. Conclusions: The RGD peptide hydrogel could be used as the carrier of MMC to establish sustained drug release system, which could inhibit scar formation after rat's ocular injury.

Glaucoma Treatment and Hydrogel: Current Insights and State of the Art

Aqueous gels formulated using hydrophilic polymers (hydrogels) and those based on stimuli-responsive polymers (in situ gelling or gel-forming systems) attract increasing interest in the treatment of several eye diseases. Their chemical structure enables them to incorporate various ophthalmic medications, achieving their optimal therapeutic doses and providing more clinically relevant time courses (weeks or months as opposed to hours and days), which will inevitably reduce dose frequency, thereby improving patient compliance and clinical outcomes. Due to its chronic course, the treatment of glaucoma may benefit from applying gel technologies as drug-delivering systems and as antifibrotic treatment during and after surgery. Therefore, our purpose is to review current applications of ophthalmic gelling systems with particular emphasis on glaucoma.

Self-Assembled Peptide Nanostructures for ECM Biomimicry

Proteins are functional building blocks of living organisms that exert a wide variety of functions, but their synthesis and industrial production can be cumbersome and expensive. By contrast, short peptides are very convenient to prepare at a low cost on a large scale, and their self-assembly into nanostructures and gels is a popular avenue for protein biomimicry. In this Review, we will analyze the last 5-year progress on the incorporation of bioactive motifs into self-assembling peptides to mimic functional proteins of the extracellular matrix (ECM) and guide cell fate inside hydrogel scaffolds.

NEDD9 Mediates the FAK/Src Signaling Pathway to Promote the Adhesion of Human Trabecular Meshwork Cells after Dexamethasone Treatment

PURPOSE

The differential gene expression of neural precursor cell expressed developmentally downregulated 9 (NEDD9) in human trabecular meshwork (HTM) cells after dexamethasone (Dex) treatment was confirmed through gene expression profiling. However, the regulatory mechanism of NEDD9 expression in HTM cells remains unknown. In this study, we investigated NEDD9 expression in HTM cells and gained a better understanding of glucocorticoid-induced glaucoma (GIG) pathophysiology.

METHODS

The Gene Expression Omnibus database and GEO2R tool were used to identify differentially expressed genes in the GSE37474 and GSE124114 datasets, and NEDD9 gene expression was found to be upregulated. Human corneoscleral segments and HTM cells were treated with 100 nM Dex or an equal volume of ethanol (0.01%) for 7 days. NEDD9 expression in TM tissues was evaluated by immunohistochemistry, and NEED9 expression in HTM cells was confirmed by RT-qPCR and western blotting. HTM cell adhesive behaviors were assessed with a cell adhesion detection kit. NEDD9 expression was knocked down with short hairpin RNA in HTM cells, and FAK/Src signaling pathway activation was found to be regulated by NEDD9.

RESULTS

After 7 days of HTM cell Dex treatment, NEDD9 expression was upregulated to be approximately twice that of control. FAK, Src, phospho-FAK, and phospho-Src expression in Dex-treated HTM cells was markedly increased. Downregulation of NEDD9 expression reduced HTM cell adhesion to the surface of culture wells and simultaneously led to a reduction in FAK, Src, phospho-FAK and phospho-Src expression.

CONCLUSIONS

NEDD9 expression is upregulated in HTM cells after Dex treatment and promotes HTM cell adhesion. These findings underscore the contribution of NEDD9 overexpression to altered HTM cell adhesion during glucocorticoid therapy and may play a key role in GIG pathological progression. Considering the similarity between GIG and primary open-angle glaucoma (POAG), our findings suggest that targeting NEDD9 may be a new therapeutic strategy for POAG patients.