NLRC3 promotes host resistance against Pseudomonas aeruginosa-induced keratitis by promoting the degradation of IRAK1.

Pseudomonas aeruginosa (PA)-induced keratitis is one of the most common and destructive bacterial diseases. The pathogenesis of PA infections is closely associated with excessive inflammatory responses. Nucleotide oligomerization domain (NOD)-like receptor (NLR) family with caspase activation and recruitment domain (CARD) containing 3 (NLRC3) protein has been implicated as a negative regulator of inflammation and antiviral response, but the role of NLRC3 in PA-induced keratitis has not been described. In the present study, we investigated the effects of NLRC3 in PA-induced keratitis and explored the underlying mechanism. We found that the expression of NLRC3 was decreased in mouse corneas and macrophages after PA infection. Overexpr-ession of NLRC3 significantly attenuated disease progression, inhibited the activation of nuclear factor-κB signaling and decreased the production of pro-inflammatory cytokines after PA infection. Furthermore, overexpression of NLRC3 promoted K48-linked polyubiquitination and degradation of interleukin-1 receptor-associated kinase 1 (IRAK1). Taken together, we demonstrated that NLRC3 has an anti-inflammatory effect on PA-induced keratitis, which may provide an improved understanding of host resistance to PA infection.