The expression of lacrimal androgen-binding proteins in mice Pseudomonas aeruginosa keratitis

Prenylcysteine oxidase 1 like protein is required for neutrophil bactericidal activities

The bactericidal function of neutrophils is dependent on a myriad of intrinsic and extrinsic stimuli. Using systems immunology approaches we identify microbiome- and infection-induced changes in neutrophils. We focus on investigating the Prenylcysteine oxidase 1 like (Pcyox1l) protein function. Murine and human Pcyox1l proteins share ninety four percent aminoacid homology revealing significant evolutionary conservation and implicating Pcyox1l in mediating important biological functions. Here we show that the loss of Pcyox1l protein results in significant reductions in the mevalonate pathway impacting autophagy and cellular viability under homeostatic conditions. Concurrently, Pcyox1l CRISPRed-out neutrophils exhibit deficient bactericidal properties. Pcyox1l knock-out mice demonstrate significant susceptibility to infection with the gram-negative pathogen Psuedomonas aeruginosa exemplified through increased neutrophil infiltrates, hemorrhaging, and reduced bactericidal functionality. Cumulatively, we ascribe a function to Pcyox1l protein in modulation of the prenylation pathway and suggest connections beween metabolic responses and neutrophil functionality.

Establishing an Experimental Pseudomonas aeruginosa Keratitis Model in Mice - Challenges and Solutions

BACKGROUND

With the ongoing increase in antimicrobial resistances seen in bacterial isolates causing a keratitis in humans, animal models have become an important tool to study new antimicrobial therapies. Nevertheless, the establishment of experimental keratitis is difficult. Here, we discuss the impact of different arrangements, including animal age, bacterial strain and dose as well as epithelium removal on the outcome of experimental keratitis. We therefore present the methods and results of our establishing experiments.

METHODS

Bacterial load determination and flow cytometry were performed using eye homogenate gained from a 72hours lasting murine Pseudomonas aeruginosa keratitis model. Additionally, the intensity of the infection was scored from 0 to 5, the mice weighed, and blood immune cells counted.

RESULTS

We found that older C57BL/6N mice (8-11 months) are more susceptible to develop a keratitis than younger mice (5-6 weeks). Epithelium removal has no major impact on infectivity and disease progression in aged mice. P. aeruginosa exoU⁺ strains, such as PA54, should preferentially be used and highly concentrated (∼ 5×10⁷ CFU). Establishing an infection with the exoU^- PAO1 derivative DSM 19880 was not possible.

CONCLUSIONS

We present a replicable method to achieve a successful experimental P. aeruginosa keratitis in C57BL/6N mice that is sustained or aggravated over the observation period of 3 days in 80% of all animals tested. Our work is of particular interest to all researchers planning the establishment of such experimental models. We show some key aspects that can simplify and quicken the procedure, ultimately saving costs and animal life.

Lacrimal androgen-binding proteins protect against Aspergillus fumigatus keratitis in mice

AIM

To clarify the regulatory mechanisms of lacrimal androgen-binding proteins (ABPs) in mice with keratitis caused by Aspergillus fumigatus (A. fumigatus).

METHODS

Mouse models of A. fumigatus keratitis were established. Lacrimal glands were removed after 24 h for general and histological comparison. Lacrimal ABPs were detected by qRT-PCR and quantitative proteomic analysis, or were detected by qRT-PCR after subconjunctival or lacrimal gland injection with dexamethasone. Unique inflammatory factors were detected by qRT-PCR, Western blot and/or immunofluorescence. Interleukin-1β (IL-1β) was injected into the lacrimal gland to explore the relationship between IL-1β and lacrimal ABPs.

RESULTS

The lacrimal glands of mice with fungal keratitis were larger than normal mice and these structures became disorganized. Moreover, the expression of ABP ε and ABP δ were increased. Subconjunctival injection with dexamethasone could reduce the size of the lacrimal gland and increase the expression of ABP ε and ABP δ, while lacrimal gland injection with dexamethasone had no obvious effects. The expression of IL-1β in the lacrimal gland of mice with A. fumigatus keratitis was increased. When IL-1β was injected into the lacrimal gland, the lacrimal gland enlarged and the expression of ABP ε and ABP δ decreased.

CONCLUSION

Lacrimal glands contributed to protection in fungal keratitis, which was not due to the involvement of inflammatory cells in mice. ABP δ and ABP ε of mice were involved in reducing the severity of corneal damage in mice with A. fumigatus keratitis. Moreover, the expression of IL-1β and ABP δ and ABP ε were intrinsically linked.