AAV for Cardiovascular Gene Delivery: Serotypes, Promoters & Injection Routes | OBiO

The cardiovascular system, also known as the circulatory system, consists primarily of the heart and blood vessels. It delivers oxygen and nutrients throughout the body while removing metabolic waste. The heart is the central organ of the system, generating the force required to maintain blood flow and provide adequate perfusion to tissues and organs. In addition to its pumping function, the heart also has endocrine activity and releases peptide hormones involved in the regulation of blood pressure, urine output, and fluid balance. Blood vessels transport blood throughout the body and play essential roles in maintaining cardiovascular homeostasis. Cardiovascular diseases remain a leading cause of death worldwide, and many cardiovascular disorders are associated with impaired or obstructed blood flow.

Recombinant adeno-associated virus (rAAV) has become an important vector for gene delivery because of its diverse capsid serotypes, relatively low immunogenicity, potential for sustained transgene expression, and broad host range. AAV-mediated gene delivery has therefore become a widely used approach in cardiovascular research, providing new opportunities for studying disease mechanisms and exploring potential gene-based therapies.

For cardiovascular applications, AAV serotype selection, promoter selection, and injection route are closely interconnected. The optimal combination depends on the target tissue, cell type, experimental model, and biological question.

1. Choosing the Right AAV Serotype for Cardiovascular Gene Delivery

AAV serotypes differ in their capsid structures, which contributes to differences in tissue tropism and transduction profiles. Several serotypes, including AAV1, AAV6, AAV8, and AAV9, have been reported to efficiently transduce the heart in animal models. Among these, AAV9 is widely used for cardiac gene delivery in mice and has also been investigated for vascular targeting.

Comparison of cardiac transduction efficiency among different AAV serotypes
(K-M R. Prasad et al., Gene Therapy, 2011)

Targeting Cardiomyocytes

Cardiomyocytes (CMs) make up the majority of the heart and generate the contractile force required for cardiac pumping. MyoAAV1A has been reported to efficiently and selectively transduce striated muscle following systemic administration. In a mouse model, tail-vein administration of MyoAAV1A enabled efficient targeting of both skeletal muscle and cardiac muscle.

Tail-vein administration of MyoAAV1A enables efficient targeting of skeletal and cardiac muscle
(Mohammadsharif Tabebordbar et al., Cell, 2021)

Targeting Vascular Endothelial Cells

Vascular endothelial cells (VECs) are distributed throughout the cardiovascular system, from the heart and large vessels to the smallest capillaries. They play essential roles in vascular development, homeostasis, and cardiovascular function.

For studies investigating the roles of specific genes in vascular biology and cardiovascular disease, endothelial cell-selective gene delivery can be particularly valuable. AAV-Vec, a specialized AAV vector, has been developed for efficient transduction of vascular endothelial cells.

Efficient transduction of vascular endothelial cells by AAV-Vec
(L. Zhang et al., Human Gene Therapy, 2019)

2. Choosing the Right Promoter for Cell-Specific Gene Delivery

The cardiovascular system contains multiple cell populations that work together to maintain cardiac and vascular function. Selecting an appropriate promoter can provide an additional layer of cell-type specificity beyond AAV capsid tropism.

Key Cell Types in Cardiovascular Research

Cardiomyocytes (CMs) are the predominant cell type in the heart and generate contractile force through coordinated contraction.

Cardiac fibroblasts (CFs) produce extracellular matrix and participate in tissue repair, remodeling, and intercellular signaling. Following pathological stimuli such as injury or inflammation, cardiac fibroblasts can transition into activated cardiac myofibroblasts (CMFs). These cells are closely associated with pathological cardiac remodeling, myocardial infarction, and heart failure.

Vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) are also major cell populations of interest in cardiovascular research.

Because these cell types have distinct biological functions, cell-specific promoters can be combined with appropriate AAV serotypes to improve the specificity of gene expression.

Cardiovascular Cell-Specific Promoters

★AAV-Heart: A Combined Strategy for Cardiac Gene Delivery

Combining Efficient AAV Tropism with a Cardiac-Specific Promoter

AAV-Heart is a cardiac gene delivery system designed to achieve efficient and specific targeting of cardiomyocytes.

According to internal testing data, tail-vein administration of AAV-Heart resulted in higher cardiac transduction than the conventional AAV9-cTnT configuration, while showing minimal detectable transduction in the liver and skeletal muscle under the tested conditions.

These results support the potential use of AAV-Heart as a research tool for studying cardiomyocyte-specific gene function and cardiovascular disease mechanisms. Its performance has also been evaluated in multiple published research applications.

AAV-Heart transduction profile based on internal testing data

3. Injection Routes and Dosing Considerations for Cardiac Gene Delivery

The appropriate administration route is another critical consideration in cardiovascular AAV experiments. For cardiac gene delivery in mice, tail-vein injection and direct myocardial injection are commonly used approaches. For vascular targeting, systemic intravenous administration is frequently considered because it enables broad exposure of the vascular system to the vector.

Common Injection Routes for Cardiovascular AAV Studies

Note: AAV doses shown in the original reference are based on administration in adult mice. Dose selection should be determined according to the AAV vector, target tissue, animal model, administration route, and experimental objective.

4. Cardiovascular Gene Delivery: Research Applications and Case Studies

Case Study 1: Investigating the CORT-GR-LAMA5 Axis in Cardiac Hypertrophy

Chronic psychological stress is closely associated with cardiac disease, but the underlying molecular mechanisms remain incompletely understood.

A study published in Advanced Science in 2025 identified the corticosterone (CORT)-glucocorticoid receptor (GR)-LAMA5 axis as a potential mechanism and therapeutic target associated with chronic psychological stress-induced cardiomyocyte hypertrophy.

In the study, an AAV-Heart vector was administered by tail-vein injection to achieve targeted knockdown of Lama5 expression in the rat heart. The results showed that inhibition of LAMA5 could alleviate cardiomyocyte hypertrophy in vivo. The AAV vector used in the study was provided by OBiO.

Key finding: LAMA5 knockdown attenuated stress-induced cardiomyocyte enlargement.

(Chuanjing Zhang et al., Advanced Science, 2025)

Case Study 2: Targeting Cardiac Fibroblasts in High-Salt Diet-Induced Cardiac Fibrosis

A high-salt diet (HSD) can induce cardiac injury, including cardiac fibrosis, through mechanisms that may occur independently of changes in blood pressure.

A study published in the British Journal of Pharmacology in 2025 reported that silencing Fn1 could protect against NaCl-induced cardiac fibrosis by reducing ferroptosis in cardiac fibroblasts.

The researchers used an AAV vector carrying the TCF21 promoter to selectively suppress FN1 expression in cardiac fibroblasts. The study found that this intervention improved HSD-induced cardiac fibrosis and reduced ferroptosis. The AAV vector used in the study was provided by OBiO.

Key finding: Cardiac fibroblast-specific FN1 suppression alleviated high-salt diet-induced cardiac fibrosis.

(Yawei Dai et al., British Journal of Pharmacology, 2025)

Case Study 3: SLC7A5 and Cardiac Remodeling

Abnormal cardiac remodeling is a major contributor to heart failure. TRIM35 has been identified as an important regulator of cell growth, immune responses, and metabolism, but its role in fibroblast-mediated cardiac remodeling has remained less clear.

A research team reported a role for fibroblast TRIM35 in cardiac remodeling and further investigated a mechanism involving SLC7A5-mediated amino acid transport and mTORC1 activation.

In the study, an AAV9 vector carrying the Postn promoter was used to suppress Slc7a5 expression in cardiac myofibroblasts. The intervention reduced deterioration of cardiac function following transverse aortic constriction (TAC) surgery. The AAV vector used in the study was provided by OBiO.

Key finding: Suppression of SLC7A5 in cardiac myofibroblasts was associated with reduced cardiac fibrosis and improved cardiac remodeling outcomes.

(Boshen Yang et al., Cell Communication and Signaling, 2024)

Case Study 4: CCR10+ Endothelial Cells in Post-MI Angiogenesis

Impaired angiogenesis is an important pathological feature of advanced heart failure and can limit cardiac repair following myocardial infarction.

A study published in Nature Communications in 2025 reported that CCL28 promotes angiogenesis and cardiac repair after myocardial infarction through CCR10+ endothelial cells in male mice.

The researchers used an AAV9 vector combined with the Tie1 promoter to selectively interfere with Ccr10 in endothelial cells of the heart and gastrocnemius muscle. The results showed that interfering with CCR10 blocked the effects of CCL28 on angiogenesis and fibrosis, supporting the conclusion that the pro-angiogenic activity of CCL28 depends on CCR10+ endothelial cells. The AAV vector used in the study was provided by OBiO.

Key finding: The angiogenic effects of CCL28 depend on CCR10+ endothelial cells.

(Kun Yang et al., Nature Communications, 2025)

Case Study 5: VSMC-Specific TNS1 and Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a potentially life-threatening vascular disease for which effective pharmacological treatments remain limited.

A study published in Circulation Research in 2025 identified a mechanism involving miR-3154, TNS1, and the TNS1-TLN1 interaction in vascular smooth muscle cells (VSMCs) that contributes to AAA development.

The researchers used an AAV9 vector carrying the SM22α promoter to knock down Tns1 specifically in VSMCs. Tns1 knockdown substantially increased the incidence of AAA in mice and increased the maximum aortic diameter following Ang II administration. These findings suggest that reduced VSMC-specific TNS1 expression may aggravate AAA development through changes in VSMC phenotype and function. The AAV vector used in the study was provided by OBiO.

Key finding: VSMC-specific loss of TNS1 promoted Ang II-induced AAA formation in ApoE^-/- mice.

(Qingbin Hou et al., Circulation Research, 2025)

5.  Key Takeaways

• AAV serotype matters: AAV1, AAV6, AAV8, AAV9, and engineered AAV vectors can exhibit different cardiovascular tissue tropism and transduction profiles.
• Promoter selection adds specificity: Combining an appropriate AAV capsid with a cell-specific promoter can improve the specificity of gene expression.
• Injection route influences delivery: Tail-vein injection and direct myocardial injection are commonly used for cardiac gene delivery in mouse models, while systemic administration can also be useful for vascular targeting.
• Different cardiovascular cell types require different strategies: Cardiomyocytes, cardiac fibroblasts, endothelial cells, and VSMCs have distinct biological functions and may require different vector configurations.
• Experimental validation is essential: Vector performance should be evaluated in the specific experimental model rather than assumed solely from published tropism data.

For cardiovascular gene delivery studies, the optimal AAV design is therefore not determined by serotype alone. Capsid tropism, promoter specificity, administration route, dose, and experimental model should be considered as an integrated vector design strategy.