Ibrutinib suppresses the activation of neutrophils and macrophages and exerts therapeutic effect on acute peritonitis induced by zymosan.

Timely treatment of acute inflammatory reactions induced by fungi or bacteria is essential to prevent infectious damage. Ibrutinib is a Bruton's tyrosine kinase (BTK) inhibitor which is used to treat various lymphoid cancers. It is also known that BTK plays important roles in innate immunity and inflammatory response. In the present study, we investigated the regulatory effects of Ibrutinib on the activation of neutrophils and macrophages and its therapeutic effects on acute peritonitis. In addition, we also studied its anti-inflammatory mechanisms. The results showed that Ibrutinib inhibited the expression and secretion of inflammatory factors in macrophages induced by multiple Toll-like receptor (TLR) agonists. In the study of neutrophils, Ibrutinib selectively suppressed the activation, superoxide release, and calcium influx of neutrophils stimulated by zymosan. Furthermore, in zymosan-induced mice acute peritonitis, Ibrutinib significantly reduced the infiltration of neutrophils into peritoneal cavity, the release of myeloperoxidase (MPO) and β-glucuronidase as well as the production of inflammatory factors in peritoneal cavity. In mechanism study, Ibrutinib selectively inhibited the phosphorylation of PLCγ2, PKCδ, and ERK1/2 in neutrophils induced by zymosan. Collectively, Ibrutinib can significantly inhibit the activation of neutrophils and macrophages by inhibiting BTK-PLCγ2-PKC signaling pathway, and has great potential to be developed into therapeutic drug for acute inflammatory diseases.