The novel Bruton tyrosine kinase inhibitor branebrutinib abrogates lipopolysaccharide/galactosamine-induced hepatic injury via limiting inflammation and oxidative stress

Liver inflammation encompasses an intricate interplay of primary injury caused by direct insults and secondary injury driven by immune dysregulation. Bruton tyrosine kinase (BTK) has recently evolved as a key player in inflammation response, particularly innate immune cell signaling and activation. Here, the second generation BTK inhibitor branebrutinib (BRB) was examined on lipopolysaccharide/galactosamine (LPS/D-GaIN)-mouse model of hepatitis to gain more insight into its role and underlying mechanisms. Mice were pretreated with BRB (1 and 2 mg/kg, oral) 2 h prior to LPS/D-GaIN (70 μg/kg and 700 mg/kg, respectively, i.p.) for 1 h and 6 h. At 6 h, BRB pretreatment dose dependently alleviated LPS/D-GaIN-induced hepatocellular injury (ALT, AST, LDH), death (apoptosis, necrosis) and proliferation (PCNA). BRB (1 and 2 mg/kg) significantly inhibited LPS/D-GaIN-induced release of TNF-α, IL-6, IL-1β and IL-10 at only 6 h, but not 1 h. This indicates that BTK is not involved in Kupffer cell-driven inflammation at the primary wave (0-1 h), but BTK is essential for the secondary inflammation wave mediated by infiltrated immune cells at 6 h. This finding was supported by BRB capability to inhibit LPS/D-GaIN-induced escalation in serum GM-CSF concentration and F4/80-positive macrophages in the liver at 6 h. Mechanistically, BRB reduced LPS/D-GaIN-phosphorylation of JNK, IκBα and STAT3 in the liver after 1 h, resulting in decreasing cytokines at 6 h. Besides, BRB activated NRF-2/HO-1 axis and limited iNOS rise at 1h that abated oxidative stress at 6h in the liver. In conclusion, BRB abrogated liver injury through mitigating the second wave of inflammation driven by recruited immune cells and hepatic oxidative stress.