The Glycoprotein 340's Scavenger Receptor Cysteine-Rich Domain Promotes Adhesion of Staphylococcus aureus and Pseudomonas aeruginosa to Contact Lens Polymers.

Contact lenses are biomaterials worn on the eye to correct refractive errors. Bacterial adhesion and colonization of these lenses results in adverse events, such as microbial keratitis. The adsorption of tear proteins to contact lens materials enhances bacterial adhesion. Glycoprotein 340 (Gp340), a tear component, is known to promote microbial colonization in the oral cavity; however, it has not been investigated in any contact lens-related adverse event. Therefore, this study examined the adsorption of Gp340 and its recombinantly expressed scavenger receptor cysteine-rich (iSRCR1Gp340) domain on two common contact lens materials, etafilcon A and lotrafilcon B, and the concomitant effects on the adherence of clinical isolates of microbial keratitis causative agents, Pseudomonas aeruginosa (PA6206; PA6294), and Staphylococcus aureus (SA38; USA300). Across all strains and materials, iSRCR1Gp340 enhanced adherence of bacteria in a dose-dependent manner. However, iSRCR1Gp340 did not modulate the lysozyme's or lactoferrin's effects on bacterial adhesion to the contact lens. The Gp340 binding serine-rich surface protein (SraP) significantly enhanced the binding of USA300 to iSRCR1Gp340-coated lenses. In addition, iSRCR1Gp340-coated surfaces had significantly diminished biofilms with the SraP mutant (ΔSraP), and there was a further reduction in biofilms with the sortase A mutant (ΔSrtA), indicating the likely involvement of additional surface proteins. Finally, the binding affinities between iSRCR1Gp340 and SraP were determined using surface plasmon resonance (SPR), where the complete SraP binding region displayed nanomolar affinity, whereas its smaller fragments adhered with micromolar affinities. This study concludes that Gp340 and its SRCR domains play an important role in bacterial adhesion to the contact lens.

Dry Eye Disease Practice in Ghana: Diagnostic Perspectives, Treatment Modalities, and Challenges.

SIGNIFICANCE: There is a dearth of studies investigating the challenges encountered in dry eye practice. Profiling these barriers is crucial to improving dry eye diagnosis and patient care. PURPOSE: This study aimed to examine the diagnostic and treatment perspectives, and challenges in dry eye practice in Ghana. METHODS: An anonymous paper-based or web survey regarding dry eye practice pattern, practice challenges, and access to diagnostic tools was distributed to 280 potential participants. RESULTS: One hundred thirteen respondents completed the survey. Case history (92.5%), fluorescein tear breakup time (87.5%), and corneal fluorescein staining (72.5%) were the topmost procedures used for dry eye diagnosis. A preserved lubricant drop was the most commonly prescribed treatment of mild, moderate, and severe dry eye at the rates of 77.0, 83.2, and 77.0%, respectively. A few respondents prescribed cyclosporine (2.7%) or punctal plugs (5.3%) across all disease severities, and none used scleral lens, autologous serum tears, or thermal pulsation. Graduate professional training influenced the practice pattern of 82.3% of respondents, whereas continuing professional education influenced less than 1%. Approximately 70.1 and 92.8% of optometrists considered referring dry eye in children and cases that are unresponsive to treatment, respectively. Eighty-eight percent of practitioners indicated they experience a challenge in dry eye practice, with limited access to diagnostic tools (77.9%) and limited availability of effective dry eye medication on the Ghanaian market (50.4%) being the most frequent challenges. More than 85% of respondents had access to a fluorescein dye or slit-lamp biomicroscope; however, none had access to a phenol red thread, lissamine green dye, osmolarity technology, or meibography device. CONCLUSIONS: Practitioners' limited access to diagnostic tools/techniques and the limited effective dry eye treatments are major challenges encountered in dry eye practice in Ghana. Addressing these will improve dry eye practice and treatment outcomes in the country.

Glycoprotein 340 in mucosal immunity and ocular surface.

Glycoprotein 340 (Gp340) is an innate immune receptor with well-defined roles in mucosal tissues. It is a normal component of mucosal fluids such as tears, breast milk, and saliva, and it is expressed in tissues such as the vagina, gastrointestinal tract, oral cavity, lung alveoli, and pancreas. In the eye, it is expressed in the lacrimal gland, cornea, conjunctiva, and retina. Investigations of the protein in wet-surfaced epithelia of the body show that the effects of Gp340 can be beneficial or harmful depending on the conformation in which it exists. In a fluid phase, Gp340 appears to be protective against mucosal infection, while in a surface-associated form it appears to promote infection. On the ocular surface, it is dysregulated in dry eye disease and inhibits twitching motility of P. aeruginosa in tears. This review discusses what is known about Gp340 in wet-surfaced mucosal epithelia and highlights the potential roles of the protein in ocular surface immunity, inflammation, and infections.