Liver-specific microRNA-122 target sequences incorporated in AAV vectors efficiently inhibits transgene expression in the liver

Gene Ther. 2011 Apr;18(4):403-10. doi: 10.1038/gt.2010.157. Epub 2010 Dec 9.


Vectors based on adeno-associated virus (AAV) are effective in gene delivery in vivo. Tissue-specific gene expression is often needed to minimize ectopic expression in unintended cells and undesirable consequences. Here, we investigated whether incorporation of target sequences of tissue-specific microRNA (miRNA) into AAV vectors could inhibit ectopic expression in tissues such as the liver and hematopoietic cells. First we inserted liver-specific miR-122 target sequences (miR-122T) into the 3'-untranslated region (UTR) of a number of AAV vectors. After intravenous delivery in mice, we found that five copies of the 20mer miR-122T reduced liver expression of luciferase by 50-fold and β-galactosidase (LacZ) by 70-fold. Five copies of miR-122T also reduced mRNA levels of a secretable protein (myostatin propeptide) from the AAV vector plasmid by 23-fold in the liver. However, gene expression in other tissues, including the heart was not inhibited. Similarly, we inserted four copies of miR-142-3pT or miR-142-5pT, both hematopoietic lineage-specific, into the 3'-UTR of the AAV-luciferase vector. We wished to see whether they could prolong transgene expression by inhibiting expression in antigen-presenting cells. However, in vivo luciferase gene expression in major tissues declined with time, regardless of the miR-142 target sequences used. Quantitative analysis of the vector DNA in various tissues revealed that the decline of transgene expression in vivo was mainly because of promoter shut-off other than loss of AAV-transduced cells by immune destruction. Moreover, transgene expression was not detected in circulating mononuclear cells after delivering AAV9 vector with or without miR142T. These results demonstrate that liver-specific miR-122 target sequence in AAV vectors was highly efficient in reducing liver expression, whereas hematopoietic miR-142 target sequences were ineffective in preventing decline of AAV vector gene expression in nonhematopoietic tissues resulted from promoter shut-off.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antigen-Presenting Cells / metabolism
  • Dependovirus / genetics*
  • Gene Expression Regulation
  • Gene Transfer Techniques*
  • Genetic Vectors*
  • Liver / metabolism*
  • Luciferases / genetics
  • Mice
  • MicroRNAs / genetics*
  • Myostatin / metabolism
  • Organ Specificity
  • Transgenes
  • beta-Galactosidase / genetics


  • MIRN122 microRNA, human
  • MicroRNAs
  • Mirn142 microRNA, mouse
  • Mstn protein, mouse
  • Myostatin
  • Luciferases
  • beta-Galactosidase