Phosphodiesterase 5a Inhibition with Adenoviral Short Hairpin RNA Benefits Infarcted Heart Partially through Activation of Akt Signaling Pathway and Reduction of Inflammatory Cytokines.

Longhu Li,Christian Paul,Zhe Jin,Yigang Wang,Jian Zhang,Dong Zhao,Yaoliang Tang

doi:10.1371/journal.pone.0145766

Abstract

IntroductionTreatment with short hairpin RNA (shRNA) interference therapy targeting phosphodiesterase 5a after myocardial infarction (MI) has been shown to mitigate post-MI heart failure. We investigated the mechanisms that underpin the beneficial effects of PDE5a inhibition through shRNA on post-MI heart failure.MethodsAn adenoviral vector with an shRNA sequence inserted was adopted for the inhibition of phosphodiesterase 5a (Ad-shPDE5a) in vivo and in vitro. Myocardial infarction (MI) was induced in male C57BL/6J mice by left coronary artery ligation, and immediately after that, the Ad-shPDE5a was injected intramyocardially around the MI region and border areas.ResultsFour weeks post-MI, the Ad-shPDE5a-treated mice showed significant mitigation of the left ventricular (LV) dilatation and dysfunction compared to control mice. Infarction size and fibrosis were also significantly reduced in Ad-shPDE5a-treated mice. Additionally, Ad-shPDE5a treatment decreased the MI-induced inflammatory cytokines interleukin (IL)-1β, IL-6, tumor necrosis factor-α, and transforming growth factor-β1, which was confirmed in vitro in Ad-shPDE5a transfected myofibroblasts cultured under oxygen glucose deprivation. Finally, Ad-shPDE5a treatment was found to activate the myocardial Akt signaling pathway in both in vivo and in vitro experiments.ConclusionThese findings indicate that PDE5a inhibition by Ad-shPDE5a via the Akt signal pathway could be of significant value in the design of future therapeutics for post-MI heart failure.

Highlights

Treatment with short hairpin RNA interference therapy targeting phosphodiesterase 5a after myocardial infarction (MI) has been shown to mitigate post-myocardial infarction (post-MI) heart failure
These findings indicate that PDE5a inhibition by Ad-shPDE5a via the Akt signal pathway could be of significant value in the design of future therapeutics for post-MI heart failure
Chronic heart failure is the leading cause of mortality and morbidity worldwide, and is commonly a result of myocardial infarction (MI)-induced remodeling of the left ventricle (LV), which is characterized by left ventricular (LV) dilatation and cardiac dysfunction[1, 2]

Summary

Methods

An adenoviral vector with an shRNA sequence inserted was adopted for the inhibition of phosphodiesterase 5a (Ad-shPDE5a) in vivo and in vitro. Myocardial infarction (MI) was induced in male C57BL/6J mice by left coronary artery ligation, and immediately after that, the Ad-shPDE5a was injected intramyocardially around the MI region and border areas. This study was approved by the IACUC at University of Cincinnati (Protocol Number: 06-03-03-01). Humane endpoints during the animal survival study were identified as animals with weight loss of 20% or greater and/or animals with respiratory distress after opening of thoracic cavity surgery. If symptoms were to occur, veterinary staff was consulted and appropriate medical treatment was provided. If animals did not respond to appropriate treatment, animals were euthanized. The animals were euthanized under anesthesia by cardioplegic solution injected into the heart to arrest the heart at diastolic phase followed by removal of vital organ

Results

Discussion

Conclusion