Augmenter of liver regeneration: an important intracellular survival factor for hepatocytes.

Abstract

BACKGROUND/AIMS:

Augmenter of liver regeneration (ALR), a protein synthesized and stored in hepatocytes, is associated with mitochondria, and possesses sulfhydryl oxidase and cytochrome c reductase activities. We sought to determine the effects of ALR depletion in hepatocytes by antisense oligonucleotide transfection.

METHODS:

Rat hepatocytes in primary culture were transfected with antisense oligonucleotide for ALR mRNA (ALR-AS) or scrambled oligonucleotide. Various analyses were performed at times up to 24h after transfection.

RESULTS:

Treatment with ALR-AS caused a decrease in ALR mRNA, cellular depletion of ALR protein primarily from mitochondria, and decreased viability. Flow cytometric analysis of ALR-AS-transfected hepatocytes stained with annexin-Vcy3 and 7-aminoactinomycin D revealed apoptosis as the predominant cause of death up to 6h; incubation beyond this time resulted in necrosis in addition to apoptosis. ALR-AS-transfection caused release of mitochondrial cytochrome c, activation of caspase-3, profound reduction in the ATP content, and cellular release of LDH. Inhibition of caspase-3 inhibited the early phase of ALR-AS-induced death but not the late phase that included ALR and LDH release.

CONCLUSIONS:

These results suggest that ALR is critically important for the survival of hepatocytes by its association with mitochondria and regulation of ATP synthesis.

• Authors: Chinnasamy Thirunavukkarasu, Lian Fu Wang, Stephen A K Harvey, Simon C Watkins, J Richard Chaillet, John Prelich, Thomas E Starzl, Chandrashekhar R Gandhi
• Journal: Journal of hepatology (J Hepatol) Vol. 48 Issue 4 Pg. 578-88 (Apr 2008) ISSN: 0168-8278 [Print] Netherlands
• PMID: 18272248 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Oligonucleotides, Antisense
• Proteins
• RNA, Messenger
• augmenter of liver regeneration factor
• Adenosine Triphosphate

Topics

• Adenosine Triphosphate (biosynthesis)
• Animals
• Apoptosis
• Cell Count
• Cell Survival (physiology)
• Cells, Cultured
• Flow Cytometry
• Hepatocytes (cytology, metabolism)
• Intracellular Fluid (metabolism)
• Mitochondria, Liver (genetics, metabolism)
• Oligonucleotides, Antisense (genetics)
• Proteins (genetics, metabolism)
• RNA, Messenger (genetics)
• Rats
• Reverse Transcriptase Polymerase Chain Reaction
• Spectrophotometry
• Transfection