Role of the NLRP3 Inflammasome in bacterial keratitis

Purpose: Inflammasomes are key molecular regulators that play important roles in inflammation. Studies have reported that the NLRP3 inflammasome is activated in response to infection with Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). However, the role of NLRP3 inflammasome in the pathogenesis of bacterial keratitis is not clearly understood. Macrophages play an important role in inflammation and infection and are known to produce the NLRP3 inflammasome. The NLRP3 inflammasome produces IL-1β a key pro-inflammatory mediator. The phenomenon of macrophage polarization during bacterial keratitis is not known, nor is the consequence of inhibiting the production of IL-1β via the NLRP3 inflammasome. So, these factors were investigated in the current study using MCC950, an NLRP3 inflammasome inhibitor in a mouse model of bacterial keratitis. Methods: The eyes of 7-10 weeks old female BALB/c were infected with strains of P. aeruginosa (6294, PAO1, 6206 and ATCC 19660) and S. aureus (31 and 38) and C57BL/6 mice with P. aeruginosa (6294 and 6206) and S. aureus (31 and 38). MCC950 (NLRP3 inflammasome inhibitor) or MCC950 + gentamicin or sterile phosphate buffer saline (PBS) was administered as topical drops (10µL of 100µM) or intraperitoneal injections (100µL of 20 mg/mL) twice a day to the infected mice. Ocular grading was performed using a slit lamp. Numbers of viable bacterial, polymorphonuclear cells and macrophages, and cytokines concentrations in eye homogenates were measured. Results: BALB/c mice infected with strains of P. aeruginosa showed a significant lowering (p<0.05) in clinical response, neutrophil numbers, and IL-1β, IL-17A, MIP-2 after treatment with MCC950 or MCC950 + gentamicin 24 and 72 hours after infection. In contrast, BALB/c mice infected with S. aureus and C57BL/6 mice did not show a significant improvement (p>0.05) in clinical outcome after treatment. Macrophage polarization was detected in BALB/c and C57BL/6 mice 72 hours after infection and treatment with MCC950 or MCC950 + gentamicin significantly inhibited the macrophage influx compared to PBS treatment at 72 hours. Conclusion: Treatments directed toward NLRP3 inflammasome inhibition could have therapeutic benefits in bacterial keratitis, as the treatment reduces the inflammation associated with keratitis.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2018

Author dc:creator

• Yerramothu, Praveen

• Mouse studies
• NLRP3 Inflammasome
• Bacterial keratitis
• Inflammation
• MCC950

Statement dc:rights

• open access
• CC BY-NC-ND 3.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by-nc-nd/3.0/au/

Language dc:language

EN

Identifier

https://doi.org/10.26190/unsworks/3586

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/60996