This study investigates the interaction of two approved and one newly developed latanoprost formulation with in vitro and in silico models of the tear film and tear film lipid layer (TFLL). Latanoprost, a prostaglandin analogue used for intraocular elevated pressure treatment, is topically delivered by nanocarriers within aqueous solutions or emulsions. The study focuses on the impact of these carriers on drug interactions with the tear film and their effect on the TFLL. Three different types of latanoprost carriers, micellar, nanoemulsion, and polymer-based, were compared, and each revealed distinct interaction patterns with the TFLL. Surface pressure kinetics demonstrated a rapid increase for the benzalkonium chloride formulation and a slow rise for the preservative-free variants. Visualization of the acellular in vitro TFLL model revealed different patterns of incorporation for each formulation, indicating unique interaction mechanisms. Molecular dynamics simulations further revealed different mechanisms of drug release in the TFLL between micellar and nanoemulsion formulations. In-depth examination highlighted the role of triglyceride molecules in replenishing the nonpolar layer of the TFLL, which suggests potential improvements in ocular surface compatibility by adjusting the quality and concentration of the oily phase. These findings suggest the potential for optimizing latanoprost formulations by tuning the oily phase-to-surfactant ratio and selecting suitable surfactants.

• Klíčová slova
• Langmuir lipid films, Monoprost, Xalatan, drug delivery systems, drug formulations, latanoprost, molecular dynamics simulations, nanomedicine, ocular drug delivery, oil-in-water nanoemulsion, ophthalmology, surface tension,
• MeSH
• antihypertenziva terapeutické užití   MeSH
• glaukom * farmakoterapie   MeSH
• latanoprost terapeutické užití   MeSH
• lidé MeSH
• nitrooční tlak MeSH
• oči * MeSH
• systémy cílené aplikace léků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antihypertenziva MeSH
• latanoprost MeSH

We employed all-atom MD simulations to investigate the impact of palmitoylation on the PAG transmembrane peptide within various lipid environments, including the less explored boundary region separating lipid-ordered (Lo) and lipid-disordered (Ld) membrane phases. We found that palmitoylation of the peptide reduces its impact on membrane thickness, particularly within the Lo and boundary environments. Despite their hydrophobic nature, the palmitoyl chains on the peptide did not significantly affect the hydration of the surrounding membrane. Interestingly, the boundary membrane environment was found to be especially compatible with the palmitoylated peptide, suggesting its potential for accumulation in phase boundaries. Our findings highlight the importance of understanding how palmitoylation-modified peptides behave within membranes, with crucial implications for cell signaling and membrane organization. This knowledge may also inform the optimization of lipid membrane-based drug delivery systems, by improving our understanding of how drugs and excipients can be most effectively arranged within these carriers.

• Klíčová slova
• Lipid membrane phases, MD simulations, Membranes, PAG, Palmitoylation,
• MeSH
• lipidové dvojvrstvy * chemie   MeSH
• lipoylace MeSH
• peptidy metabolismus   MeSH
• simulace molekulární dynamiky * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• lipidové dvojvrstvy * MeSH
• peptidy MeSH

Glaucoma is a leading cause of blindness worldwide, with elevated intraocular pressure being a major risk factor for its development and progression. First-line treatment for glaucoma relies on the administration of prostaglandin analogs, with latanoprost being the most widely used. However, before latanoprost reaches the cornea, it must pass through the tear film and tear film lipid layer (TFLL) on the ocular surface. Given the significant lipophilicity of latanoprost, we hypothesize that TFLL could, to a certain extent, act as a reservoir for latanoprost, releasing it on longer time scales, apart from the fraction being directly delivered to the cornea in a post-instillation mechanism. We investigated this possibility by studying latanoprost behavior in acellular in vitro TFLL models. Furthermore, we employed in silico molecular dynamics simulations to rationalize the experimental results and obtain molecular-level insight into the latanoprost-TFLL interactions. Our experiments demonstrated that latanoprost indeed accumulates in the TFLL models, and our simulations explain the basis of the accumulation mechanism. These results support the hypothesis that TFLL can serve as a reservoir for latanoprost, facilitating its prolonged release. This finding could have significant implications for optimizing glaucoma treatment, especially in the development of new drug delivery systems targeting the TFLL.

• Klíčová slova
• Glaucoma, Latanoprost, Ophthalmology, Tear film, Tear film lipid layer, Topical delivery,
• MeSH
• antihypertenziva terapeutické užití   MeSH
• glaukom * farmakoterapie   MeSH
• latanoprost terapeutické užití   MeSH
• lidé MeSH
• nitrooční tlak MeSH
• počítačová simulace MeSH
• rohovka MeSH
• slzy MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antihypertenziva MeSH
• latanoprost MeSH

Benzalkonium chloride (BAK) compounds are commonly used in topical ophthalmic products as preservatives and stabilizers. BAK mixtures containing several compounds with different alkyl chain lengths are typically used. However, in chronic eye conditions, such as dry eye disease and glaucoma, the accumulation of adverse effects of BAKs was observed. Hence, preservative-free eye drops formulations are preferred. On the other hand, selected long-chain BAKs, particularly cetalkonium chloride, exhibit therapeutic functions, promoting epithelium wound healing and tear film stability. Nevertheless, the mechanism of BAKs influence on the tear film is not fully understood. By employing in vitro experimental and in silico simulation techniques, we elucidate the action of BAKs and demonstrate that long-chain BAKs accumulate in the lipid layer of the tear film model, stabilizing it in a concentration-dependent fashion. In contrast, short-chain BAKs interacting with the lipid layer compromise the tear film model stability. These findings are relevant for topical ophthalmic drug formulation and delivery in the context of selecting proper BAK species and understanding the dose dependency for tear film stability.

• Klíčová slova
• Benzalkonium chloride, Lipid films, Molecular dynamics, Tear film, Tear film lipid layer, Topical ophthalmic formulations,
• MeSH
• benzalkoniové sloučeniny škodlivé účinky   MeSH
• konzervační prostředky farmaceutické * farmakologie   MeSH
• lidé MeSH
• lipidy farmakologie   MeSH
• oční roztoky MeSH
• slzy MeSH
• syndromy suchého oka * farmakoterapie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• benzalkoniové sloučeniny MeSH
• konzervační prostředky farmaceutické * MeSH
• lipidy MeSH
• oční roztoky MeSH

Linker for activation in T cells (LAT) is a critical regulator of T-cell development and function. It organises signalling events at the plasma membrane. However, the mechanism, which controls LAT localisation at the plasma membrane, is not fully understood. Here, we studied the impact of helix-breaking amino acids, two prolines and one glycine, in the transmembrane segment on localisation and function of LAT. Using in silico analysis, confocal and super-resolution imaging and flow cytometry, we demonstrate that central proline residue destabilises transmembrane helix by inducing a kink. The helical structure and dynamics are further regulated by glycine and another proline residue in the luminal part of LAT transmembrane domain. Replacement of these residues with aliphatic amino acids reduces LAT dependence on palmitoylation for sorting to the plasma membrane. However, surface expression of these mutants is not sufficient to recover function of nonpalmitoylated LAT in stimulated T cells. These data indicate that geometry and dynamics of LAT transmembrane segment regulate its localisation and function in immune cells.

• Klíčová slova
• LAT, MD simulations, T cells, microscopy, transmembrane domain,
• MeSH
• adaptorové proteiny signální transdukční chemie   genetika   metabolismus   MeSH
• buněčná membrána metabolismus   MeSH
• glycin genetika   metabolismus   MeSH
• interferenční mikroskopie MeSH
• Jurkat buňky MeSH
• konfokální mikroskopie MeSH
• lidé MeSH
• membránové proteiny chemie   genetika   metabolismus   MeSH
• mutace MeSH
• prolin genetika   metabolismus   MeSH
• proteinové domény MeSH
• sekundární struktura proteinů MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• simulace molekulární dynamiky MeSH
• T-lymfocyty metabolismus   MeSH
• vápník metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adaptorové proteiny signální transdukční MeSH
• glycin MeSH
• LAT protein, human MeSH Prohlížeč
• membránové proteiny MeSH
• prolin MeSH
• vápník MeSH