Carma3 is an intracellular scaffolding protein that can form complex with Bcl10 and Malt1 to mediate G protein-coupled receptor- or growth factor receptor-induced NF-κB activation. However, the in vivo function of Carma3 has remained elusive. Here, by establishing a Con A-induced autoimmune hepatitis model, we show that liver injury is exacerbated in Carma3 -/- mice. Surprisingly, we find that the Carma3 expression level is higher in liver sinusoidal endothelial cells (LSECs) than in hepatocytes in the liver. In Carma3 -/- mice, Con A treatment induces more LSEC damage, accompanied by severer coagulation. In vitro we find that Carma3 localizes at mitochondria and Con A treatment can trigger more mitochondrial damage and cell death in Carma3-deficient LSECs. Taken together, our data uncover an unrecognized role of Carma3 in maintaining LSEC integrity, and these results may extend novel strategies to prevent liver injury from toxic insults.
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