Heart failure-inducible gene therapy targeting protein phosphatase 1 prevents progressive left ventricular remodeling.

Abstract

BACKGROUND:

The targeting of Ca(2+) cycling has emerged as a potential therapy for the treatment of severe heart failure. These approaches include gene therapy directed at overexpressing sarcoplasmic reticulum (SR) Ca(2+) ATPase, or ablation of phospholamban (PLN) and associated protein phosphatase 1 (PP1) protein complexes. We previously reported that PP1β, one of the PP1 catalytic subunits, predominantly suppresses Ca(2+) uptake in the SR among the three PP1 isoforms, thereby contributing to Ca(2+) downregulation in failing hearts. In the present study, we investigated whether heart-failure-inducible PP1β-inhibition by adeno-associated viral-9 (AAV9) vector mediated gene therapy is beneficial for preventing disease progression in genetic cardiomyopathic mice.

METHODS:

We created an adeno-associated virus 9 (AAV9) vector encoding PP1β short-hairpin RNA (shRNA) or negative control (NC) shRNA. A heart failure inducible gene expression system was employed using the B-type natriuretic protein (BNP) promoter conjugated to emerald-green fluorescence protein (EmGFP) and the shRNA sequence. AAV9 vectors (AAV9-BNP-EmGFP-PP1βshRNA and AAV9-BNP-EmGFP-NCshRNA) were injected into the tail vein (2×10(11) GC/mouse) of muscle LIM protein deficient mice (MLPKO), followed by serial analysis of echocardiography, hemodynamic measurement, biochemical and histological analysis at 3 months.

RESULTS:

In the MLPKO mice, BNP promoter activity was shown to be increased by detecting both EmGFP expression and the induced reduction of PP1β by 25% in the myocardium. Inducible PP1βshRNA delivery preferentially ameliorated left ventricular diastolic function and mitigated adverse ventricular remodeling. PLN phosphorylation was significantly augmented in the AAV9-BNP-EmGFP-PP1βshRNA injected hearts compared with the AAV9-BNP-EmGFP-NCshRNA group. Furthermore, BNP production was reduced, and cardiac interstitial fibrosis was abrogated at 3 months.

CONCLUSION:

Heart failure-inducible molecular targeting of PP1β has potential as a novel therapeutic strategy for heart failure.

• Authors: Yosuke Miyazaki, Yasuhiro Ikeda, Kozo Shiraishi, Shizuka N Fujimoto, Hidekazu Aoyama, Koichi Yoshimura, Makoto Inui, Masahiko Hoshijima, Hideko Kasahara, Hiroki Aoki, Masunori Matsuzaki
• Journal: PloS one (PLoS One) Vol. 7 Issue 4 Pg. e35875 ( 2012) ISSN: 1932-6203 [Electronic] United States
• PMID: 22558250 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Calcium-Binding Proteins
• Isoenzymes
• RNA, Small Interfering
• phospholamban
• Natriuretic Peptide, Brain
• Green Fluorescent Proteins
• Protein Phosphatase 1
• Sarcoplasmic Reticulum Calcium-Transporting ATPases

Topics

• Animals
• Calcium Signaling (genetics)
• Calcium-Binding Proteins (antagonists & inhibitors, metabolism)
• Cardiomyopathies (genetics, metabolism, therapy)
• Dependovirus (genetics)
• Gene Expression
• Genetic Therapy (methods)
• Genetic Vectors
• Green Fluorescent Proteins (genetics)
• Heart Failure (genetics, metabolism, therapy)
• Isoenzymes (antagonists & inhibitors, genetics, metabolism)
• Mice
• Mice, Knockout
• Myocardium (metabolism, pathology)
• Natriuretic Peptide, Brain (genetics)
• Promoter Regions, Genetic
• Protein Phosphatase 1 (antagonists & inhibitors, genetics, metabolism)
• RNA, Small Interfering (genetics)
• Sarcoplasmic Reticulum Calcium-Transporting ATPases (metabolism)
• Ventricular Remodeling (genetics)