Modulation of Bcl-x Alternative Splicing Induces Apoptosis of Human Hepatic Stellate Cells

Abstract EN

Liver fibrosis is a major cause of morbidity and mortality worldwide due to chronic viral hepatitis and, more recently, from fatty liver diseases.

Activation and proliferation of hepatic stellate cells (HSCs) represent a key aspect of fibrogenesis and are associated with progressive reduction of HSC apoptosis.

Bcl-x, an antiapoptotic member of Bcl-2 gene family, plays a role in apoptosis regulation in mammalian cells.

Through alternative splicing, the Bcl-x gene yields two major protein isoforms with opposing functions, antiapoptotic Bcl- x L and proapoptotic Bcl- x S .

This study aimed to investigate the role of Bcl-x and its alternate splicing in HSC apoptosis.

The results indicated that the expression of Bcl- x L was dramatically higher than Bcl-2 in activated human HSCs.

The relative expression of Bcl- x L over Bcl- x S increased gradually when HSCs were activated in cell culture, which was consistent with the increase in apoptosis resistance of activated HSCs.

Redirection of Bcl-x splicing by an antisense oligonucleotide from the antiapoptotic isoform to the proapoptotic isoform induced death of HSCs without other apoptosis stimuli.

We conclude that Bcl-x plays a role in regulation of HSC apoptosis and modulation of Bcl-x alternative splicing may become a novel molecular therapy for liver fibrosis.