AAV-Mediated Gene Transfer to the Heart and Liver

The adeno-associated virus (AAV) vector can efficiently transfects a wide variety of cells and tissues, which are suitable for long term gene expression in non-dividing cells and short term in dividing cells with a low cytotoxicity and immunogenicity. The adeno-associated virus (AAV) of different serotypes and promoters render the virus with different tropism to different tissues and cells. Therefore, in order to improve the specificity of AAV virus, the different serotypes and promoters had been developed by scientists.
1. Heart-specific promoter cTnT mediated heart-specific expression.
rAAV-CMV-Luc, rAAV-cTnT-Luc and AAV-cTnT-EGFP viruses were constructed respectively. Mouse were injected through the jugular vein. After 4 weeks, the expression of luciferase reporter gene was detected in each tissue by in vivo luminescence imaging of mice (heart; H, liver; L, thymus; T, kidney; K, spleen; S, gastrocnemius muscle; Gn, brain; B, intercostal muscle; Ic)^Ref1.

Fig.1 | Schematic representation of wild-type AAV and AAV vectors.

Results show that compared with the CMV promoter widely expressed, cTnT promoter can realize specificity express in heart cells, and the luciferase expression levels in heart is 640 times higher than that in the liver, further confirmed CTnT promoter expression is highly specific in heart tissue.
2. Liver-specific promoter TBG mediated liver-specific expression.
The liver is an important target organ for gene therapy with adeno-associated virus (AAV) vectors, both for the production of secreted proteins which can be expressed in hepatocytes as well as for gene replacement therapy for metabolic liver diseases. The adeno-associated virus 8 (AAV8) are highly efficient in liver transduction and can be easily administered by intravenous injection. The authors constructed AAV-TBG-GFP virus and infected young rhesus monkeys, adult macaques, dogs and adult macaques, respectively. Then the immunofluorescence staining on liver after transfer with AAV8 were labeled with GFP antibody, and the central veins were labeled with glutamine synthase (GS).

Fig.2 | Immunofluorescence staining on liver after gene transfer with AAV8 expressing GFP from the TBG promoter.

The results showed that AAV-TBG-EGFP could specifically infect the liver of mice and was highly expressed. At present, Gene transfer to the liver using AAV is achieved by intravenous injection, either via a tail or portal vein. And the expression level of the portal vein injection was about 50% higher than that of the tail vein. However, the portal vein injection technique requires surgical expertise, and can only be performed on adult mice.

BrainVTA can provide pre-made products and customized services with the specific promoters and serotypes for heart, liver and other tissues for researchers which can meet various scientific research needs.

Tissue	Promoter	Serotypes
Heart	cTnT	1,6,8,9.
Heart	CS-CRM4-αMHC	1,6,8,9.
Liver	TBG	8

For more details, please email us at sales@brainvta.com.

References
1. Robust Cardiomyocyte-Specific Gene Expression Following Systemic Injection of AAV: In Vivo Gene Delivery Follows a Poisson Distribution.
2. Inverse zonation of hepatocyte transduction with AAV vectors between mice and non-human primates.