The pathogenesis of non-
alcoholic steatohepatitis (NASH) is not fully understood. In the present study, both in vitro and in vivo
vimentin expression and secretion in NASH were investigated. The exposure of
palmitate and
lipopolysaccharide (LPS) to HepG2 cells enhanced
caspase-3 activity and
vimentin expression, respectively. The combined effects of both treatments on
vimentin expression and
caspase-3 activation appeared to be synergic. In contrast, blockade of
caspase-3 activity by zVADfmk resulted in a significant reduction of cleaved
vimentin and secreted
vimentin into the culture supernatant. Similarly,
lipid accumulation and
inflammation occurred in mice fed a
methionine-
choline-deficient diet; thus,
vimentin expression and serum cleaved
vimentin levels were increased. However,
vimentin was not significantly upregulated, and no cleavage occurred in mice fed a high-fat diet. It was conclusively determined that
lipid accumulation in hepatocytes induces apoptosis through a
caspase-3 dependent pathway; whereas, LPS stimulates
vimentin expression, leading to its cleavage and secretion. Increased
vimentin fragment levels indicated the existence of substantial hepatocellular death via an apoptotic mechanism.