Multifunctional Cerium Oxide Nanozyme for Synergistic Dry Eye Disease Therapy.

Dry eye disease (DED) is a chronic multifactorial ocular surface disease mainly caused by the instability of tear film, characterized by a series of ocular discomforts and even visual disorders. Oxidative stress has been recognized as an upstream factor in DED development. Diquafosol sodium (DQS) is an agonist of the P2Y2 receptor to restore the integrity/stability of the tear film. With the ability to alternate between Ce3+ and Ce4+, cerium oxide nanozymes could scavenge overexpressed reactive oxygen species (ROS). Hence, a DQS-loaded cerium oxide nanozyme was designed to boost the synergistic treatment of DED. Cerium oxide with branched polyethylenimine-graft-poly(ethylene glycol) as nucleating agent and dispersant was fabricated followed with DQS immobilization via a dynamic phenylborate ester bond, obtaining the DQS-loaded cerium oxide nanozyme (defined as Ce@PBD). Because of the ability to mimic the cascade processes of superoxide dismutase and catalase, Ce@PBD could scavenge excessive accumulated ROS, showing strong antioxidant and anti-inflammatory properties. Meanwhile, the P2Y2 receptors in the conjunctival cells could be stimulated by DQS in Ce@PBD, which can relieve the incompleteness and instability of the tear film. The animal experiments demonstrated that Ce@PBD significantly restored the defect of the corneal epithelium and increased the number of goblet cells, with the promotion of tear secretion, which was the best among commercial DQS ophthalmic solutions.

Non-viral gene therapy using RNA interference with PDGFR-α mediated epithelial-mesenchymal transformation for proliferative vitreoretinopathy.

Fibrotic eye diseases, a series of severe oculopathy, that will destroy normal ocular refractive media and imaging structures. It is characterized by the transformation of the epithelial cells into mesenchyme cells. Proliferative vitreoretinopathy (PVR) is one of these representative diseases. In this investigation, polyethylene glycol grafted branched Polyethyleneimine (PEI-g-PEG) was used as a non-viral gene vector in gene therapy of PVR to achieve anti-fibroblastic effects in vitro and in vivo by interfering with platelet-derived growth factor alpha receptor (PDGFR-α) in the epithelial-mesenchymal transition (EMT) of retinal pigment epithelium (RPE) cells. The plasmid was wrapped by electrostatic conjugation. Physical characterization of the complexes indicated that the gene complexes were successfully prepared. In vitro, cellular experiments showed excellent biocompatibility of PEI-g-PEG, efficient cellular uptake of the gene complexes, and successful expression of the corresponding fragments. Through gene silencing technique, PEI-g-PEG/PDGFR-α shRNA successfully inhibited the process of EMT in vitro. Furthermore, in vivo animal experiments suggested that this method could effectively inhibit the progression of fibroproliferative membranes of PVR. Herein, a feasible and promising clinical idea was provided for developing non-viral gene vectors and preventing fibroblastic eye diseases by RNA interference (RNAi) technology.

Non-viral gene coating modified IOL delivering PDGFR-α shRNA interferes with the fibrogenic process to prevent posterior capsular opacification.

Posterior capsule opacification (PCO), the most common complication after cataract surgery, is caused by the proliferation, migration and epithelial-mesenchymal transition (EMT) of residual lens epithelial cells in the capsule bag. Although the surface modification and drug loading of intraocular lens (IOLs) have been effective in preventing PCO to some extent, the intraocular safety of anti-proliferative drug application is still a major limitation in clinical application. In this study, we used non-viral gene delivery systems in combination with layer-by-layer (LBL) self-assembly technology, and the modified IOL could effectively prevent the development of PCO by interfering with the EMT process mediated by the platelet-derived growth factor receptor-α (PDGFR-α). Herein, the gene fragments were wrapped by electrostatic conjugation using polyethyleneimine-graft-poly(ethylene glycol) to form gene complexes. Gene complexes were characterized by dynamic light scattering, transmission electron microscopy (TEM) and agarose gel electrophoresis, and evaluated for storage and serum stability. The layer assembly behavior of the IOL surface, changes in optical properties and the release behavior of the gene complexes were characterized using quartz crystal microbalance, UV-vis, contact angle and TEM. In vitro experiments showed that the IOL coating has good bio-compatibility and can achieve the corresponding transfection effect, and the released gene complexes exhibited excellent cell internalization and lysosomal escape behaviors, as well as effective inhibition of PDGFR-α expression and its mediated EMT process. The early PCO prevention effect and bio-compatibility evaluation of the modified IOL in vivo were evaluated by implantation into animal eyes. This study provides a new strategy for the development of surface modifications of small nucleic acid drugs and non-toxic EMT interference therapies for PCO.

Overexpression of MePMEI1 in Arabidopsis enhances Pb tolerance.

Pb is one of the most ubiquitously distributed heavy metal pollutants in soils and has serious negative effects on plant growth, food safety, and public health. Pectin methylesterase inhibitors (PMEIs) play a pivotal role in regulating the integrity of plant cell walls; however, the molecular basis by which PMEIs promote plant resistance to abiotic stress remains poorly understood. In this study, we identified a novel PMEI gene, MePMEI1, from Manihot esculenta, and determined its role in plant resistance to Pb stress. The expression of MePMEI1 was remarkably upregulated in the roots, stems, and leaves of cassava plants following exposure to Pb stress. An analysis of subcellular localization revealed that the MePMEI1 protein was localized in the cell wall. MePMEI1 inhibited commercial orange peel pectin methyltransferase (PME), and the expression of MePMEI1 in Arabidopsis decreased the PME activity, indicating that MePMEI1 can inhibit PME activity in the cell wall. Additionally, the overexpression of MePMEI1 in Arabidopsis reduced oxidative damage and induced the thickening of cell walls, thus contributing to Pb tolerance. Altogether, the study reports a novel mechanism by which the MePMEI1 gene, which encodes the PMEI protein in cassava, plays an essential role in promoting tolerance to Pb toxicity by regulating the thickness of cell walls. These results provide a theoretical basis for the MePMEI1-mediated plant breeding for increasing heavy metal tolerance and provide insights into controlling Pb pollution in soils through phytoremediation in future studies.