Liver Bid suppression for treatment of fibrosis associated with non-alcoholic steatohepatitis

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• 作者：Akiko Eguchi¹ ; Xavier De Mollerat Du Jeu² ; Casey D. Johnson¹ ; Andronikou Nektaria² ; Ariel E. Feldstein¹ ; ^{afeldstein@ucsd.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：NAFLD ; non-alcoholic fatty liver disease ; NASH ; non-alcoholic steatohepatitis ; CDAA ; chorine-deficient L-amino acid defined ; BidΔhep ; hepatocyte-specific Bid deficient ; EV ; extracellular vesicle
• 刊名：Journal of Hepatology
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：64
• 期：3
• 页码：699-707
• 全文大小：2759 K

文摘

Liver fibrosis is the most worrisome feature of non-alcoholic steatohepatitis (NASH). Growing evidence supports a link between hepatocyte apoptosis and liver fibrogenesis. Our aim was to determine the therapeutic efficacy and safety of liver Bid, a key pro-apoptotic molecule, suppression using RNA interference (RNAi) for the treatment of fibrosis.

Methods

First, we optimized the delivery system for Bid siRNA in mice using ten different stealth RNAi siRNAs and two lipid formulations -Invivofectamine2.0 and a newly developed Invivofectamine3.0 – that have been designed for high efficacy accumulation in the liver, assessed via real-time PCR of Bid mRNA. Next, C57BL/6 mice were placed on a choline-deficient L-amino acid defined (CDAA) diet. After 19 weeks of the CDAA diet, a time point that results in severe fibrotic NASH, mice were injected with the selected Bid siRNA-Invivofectamine3.0 biweekly for three weeks. Additionally hepatocyte-specific Bid deficient (Bid^Δhep) mice were placed on CDAA diet for 20 weeks.

Results

A maximum Bid knockdown was achieved at 1.5 mg/kg siRNA with Invivofectamine3.0, whereas it was at 7 mg/kg with Invivofectamine2.0. In NASH mice, after 3 weeks of treatment, BID protein was reduced to 10% and this was associated with an improvement in liver fibrosis and inflammation associated with a marked reduction in TUNEL positive cells, caspase 3 activation, and a reduction in mitochondrial BAX and BAK. Bid^Δhep mice showed similar protection from fibrotic changes.

Conclusion

Our data demonstrate that liver Bid suppression by RNAi technology, as well as hepatocyte-specific Bid deficiency, improves liver fibrosis coupled with a reduction of inflammation in experimental NASH. These findings are consistent with existing evidence that hepatocyte apoptosis triggers hepatic stellate cell activation and liver fibrosis and suggest that Bid inhibition may be useful as an antifibrotic NASH therapy.