Endothelial cells are damaged by autophagic induction before hepatocytes in Con A-induced acute hepatitis

Abstract

We have reported both T-cell-dependent and -independent hepatitis in immunocompetent and immunodeficiency mice, respectively, after intravenous injection of Con A in mice. The mode of hepatocyte cell death is different: autophagy for T-cell-independent hepatitis in contrast to apoptosis for T-cell-dependent one. In this study, we further demonstrate that liver blood vessels are the first target in both modes. The infused Con A bond to the hepatic vascular endothelial cells and cause its damage with autophagy. Before the elevation of the serum alanine aminotransferase at 6 h post-injection, the plasma leakage and hemorrhage occur at 1-3 h without inflammation. Con A induces autophagy of endothelial cells and hemorrhage that is enhanced by IFN-gamma. Using the endothelial cell line HMEC-1, a dose- and time-dependent cell death with autophagic LC3-II (microtubule-associated protein light chain 3) conversion was induced by Con A and was enhanced by IFN-gamma. In conclusion, Con A induced autophagy on hepatic endothelial cells; the damage of liver blood vessel occurs before the induction of T-cell-dependent hepatitis via apoptosis or T-cell-independent hepatitis via autophagy.