The sealed anatomical features of the eye and its physiological activity that rapidly removes drugs are called anatomical and physiological barriers, which are the cause of more than 90% of drug loss. This aspect remains a critical issue in eye surface medication. Thus, promoting tissue permeability of drugs as well as prolonging their retention on the eye surface can improve their bioavailability and enhance their therapeutic effects. Thanks to the existence of a negatively charged mucin layer on the eye surface, several peptide-decorated polymeric micelles were prepared to enhance the interaction between the micelle and eye surface, thus prolonging the drug retention on the eye surface and promoting its tissue permeability. Tacrolimus (also known as FK506) is a hydrophobic macrolide immunosuppressant used to treat dry eye syndrome and other eye diseases. However, its hydrophobic nature makes its delivery as a topical eye surface medication difficult, with the risk of side effects due to overdoses. Therefore, the aim of this work is to evaluate the ability of FK506 micelles in promoting their permeability on the eye surface. Our results showed that the positively charged nanomicelles could significantly prolong FK506 retention on the eye surface and enhance its corneal permeability in ex vivo and in vivo conditions. FK506 nanomicelles exhibited superior curing effects against dry eye diseases than the FK506 suspension and a commercial FK506 formula. It exerted better inhibitory effects on eye surface inflammation and corneal epithelium apoptosis when examined by a slip lamp and a transferase-mediated dUTP nick end labeling assay, respectively. Further assays revealed the higher suppressive effects on the expression of several inflammation-related factors at an mRNA and protein level. Hence, our results suggested that these positively charged nanomicelles might be a good drug delivery system for ocular surface medication.

PURPOSE. The purpose of this study was to determine whether either a hyperosmotic or oxidative stress induces NLRP3 inflammasome activation and increases in bioactive IL-1b secretion through transient receptor potential melastatin 2 (TRPM2) activation in primary human corneal epithelial cells (PHCECs). METHODS.Real-time PCR, Western blots, and immunofluorescent staining were used to evaluate TRPM2 and NLRP3, ASC, caspase-1, and IL-1b mRNA and protein expression levels, respectively. A CCK-8 assay evaluated cell viability. Hyperosmotic 500 mOsm and oxidative 0.5 mM H 2 O 2 stresses were imposed. TRPM2 expression was inhibited with a TRPM2 inhibitor, 20 lM N-(p-amylcinnamoyl) anthranilic acid (ACA), or TRPM2 siRNA knockdown.RESULTS. In the hypertonic medium, TRPM2, NLRP3, ASC, caspase-1, and IL-1b gene and protein expression levels rose after 4 hours (P 0.043), whereas ACA preincubation suppressed these rises (P 0.044). Similarly, H 2 O 2 upregulated TRPM2 protein expression by 80%, and induced both NLRP3 inflammasome activation and increased bioactive IL-1b secretion (P 0.036), whereas ACA pretreatment suppressed these effects (P 0.029). TRPM2 siRNA transfection reduced TRPM2 gene expression by 70% (P ¼ 0.018) in this hyperosmotic medium and inhibited the increases in NLRP3, caspase-1, and IL-1b gene (P 0.028) and protein expression (P 0.037).CONCLUSIONS. TRPM2 activation by either a hyperosmotic or oxidative stress contributes to mediating increases in NLRP3 inflammasome activity and bioactive IL-1b expression because inhibiting TRPM2 activation or its expression blunted both of these responses in PHCECs. This association points to the possibility that TRPM2 is a viable target to suppress hyperosmotic-induced corneal epithelial inflammation.

Ocular surface microbiome changes can affect meibomian gland dysfunction (MGD) development. This study aimed to delineate differences among the microbiome of eyelid skin, conjunctiva, and meibum in healthy controls (HCs) and patients afflicted with MGD. METHODS. Shotgun metagenomic analysis was used to determine if there are differences between the microbial communities in ocular sites surrounding the meibomian gland in healthy individuals and patients afflicted with MGD. RESULTS. The meibum bacterial content of these microbiomes was dissimilar in these two different types of individuals. Almost all of the most significant taxonomic changes in the meibum microbiome of individuals with MGD were also present in their eyelid skin, but not in the conjunctiva. Such site-specific microbe pattern changes accompany increases in the gene expression levels controlling carbohydrate and lipid metabolism. Most of the microbiomes in patients with MGD possess a microbe population capable of metabolizing benzoate. Pathogens known to underlie ocular infection were evident in these individuals. MGD meibum contained an abundance of Campylobacter coli, Campylobacter jejuni, and Enterococcus faecium pathogens, which were almost absent from HCs. Functional annotation indicated that in the microbiomes of MGD meibum their capability to undergo chemotaxis, display immune evasive virulence, and mediate type IV secretion was different than that in the microbiomes of meibum isolated from HCs. CONCLUSIONS. MGD meibum contains distinct microbiota whose immune evasive virulence is much stronger than that in the HCs. Profiling differences between the meibum microbiome makeup in HCs and patients with MGD characterizes changes of microbial communities associated with the disease status.

Chitosan (CS) based nanoparticles (NPs) have several advantages in delivering drugs. They are usually prepared in a micro-emulsion solvent system but this route can leave significant levels of potentially harmful organic solvent residue in the NPs. In this study, we prepared CS based nanocomposites using charge driven self-assembly in an aqueous buffer, thus avoiding the use of organic solvents. Doxorubicin (DOX) was covalently attached to positive charged CS with a legumain substrate peptide to confer targeted drug release property, since legumain is often overexpressed in tumors or tumor associated micro environments. This DOX prodrug solution interacted with negative charged methoxyl poly (ethylene glycol)-block-poly (glutamic acid) copolymer (PEG-PGA) in an aqueous buffer forming nanocomposite with a regular morphology. The particle size and zeta potential of these NPs was regulated by the addition of different PEG-PGA concentrations into the DOX prodrug solution. Due to its potential for legumain triggered release, this DOX NP exhibited enhanced cytotoxicity against choroidal melanoma cell line (Mum-2C) and reduced cytotoxicity on normal human corneal epithelial cells (HCEC), suggesting a good potential for enhanced targeted delivery of chemotherapeutic agents. A chitosan based nanocomposite with legumain sensitive properties are rapidly controllable prepared in aqueous buffer by charge driven self-assembly strategy, without using micro-emulsion solvent system and cross-linking agents.