3K3A-Activated Protein C Prevents Microglia Activation, Inhibits NLRP3 Inflammasome and Limits Ocular Inflammation

Dahlia Palevski, Gil Ben-David, Yehonatan Weinberger, Rabeei Haj Daood, José A. Fernández, Ivan Budnik, Sarina Levy-Mendelovich, Gili Kenet, Yael Nisgav, Dov Weinberger, John H. Griffin, Tami Livnat*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


3K3A-Activated Protein C (APC) is a recombinant variant of the physiological anticoagulant APC with pleiotropic cytoprotective properties albeit without the bleeding risks. The anti-inflammatory activities of 3K3A-APC were demonstrated in multiple preclinical injury models, including various neurological disorders. We determined the ability of 3K3A-APC to inhibit ocular inflammation in a murine model of lipopolysaccharide (LPS)-induced uveitis. Leukocyte recruitment, microglia activation, NLRP3 inflammasome and IL-1β levels were assessed using flow cytometry, retinal cryosection histology, retinal flatmount immunohistochemistry and vascular imaging, with and without 3K3A-APC treatment. LPS triggered robust inflammatory cell recruitment in the posterior chamber. The 3K3A-APC treatment significantly decreased leukocyte numbers and inhibited leukocyte extravasation from blood vessels into the retinal parenchyma to a level similar to controls. Resident microglia, which underwent an inflammatory transition following LPS injection, remained quiescent in eyes treated with 3K3A-APC. An inflammation-associated increase in retinal thickness, observed in LPS-injected eyes, was diminished by 3K3A-APC treatment, suggesting its clinical relevancy. Finally, 3K3A-APC treatment inhibited inflammasome activation, determined by lower levels of NLRP3 and its downstream effector IL-1β. Our results highlight the anti-inflammatory properties of 3K3A-APC in ocular inflammation and suggest its potential use as a novel treatment for retinal diseases associated with inflammation.

Original languageEnglish
Article number14196
JournalInternational Journal of Molecular Sciences
Issue number22
StatePublished - Nov 2022


FundersFunder number
Study of Blindness
Visual Disorders
National Institutes of Health
National Heart, Lung, and Blood InstituteR01HL142975
Sackler Faculty of Medicine, Tel-Aviv University


    • NLRP3
    • activated protein C
    • inflammasome
    • inflammation
    • microglia
    • uveitis


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