Intravenous Gene Therapy With Pim-1 Via a Cardiotropic Viral Vector Halts the Progression of Diabetic Cardiomyopathy Through Promotion of Prosurvival Signaling
Rationale: Studies in transgenic mice showed the key role of Pim-1 (proviral integration site for Moloney murine leukemia virus-1) in the control of cardiomyocyte function and viability.
Objective: We investigated whether Pim-1 represents a novel mechanistic target for the cure of diabetic cardiomyopathy, a steadily increasing cause of nonischemic heart failure.
Methods and Results: In streptozotocin-induced type 1 diabetic mice, Pim-1 protein levels declined during progression of cardiomyopathy, along with upregulation of Pim-1 inhibitors, protein phosphatase 2A, and microRNA-1. Moreover, diabetic hearts showed low levels of antiapoptotic B-cell lymphoma-2 (Bcl-2) protein and increased proapoptotic caspase-3 activity. Studies on adult rat cardiomyocytes and murine cardiac progenitor cells challenged with high glucose confirmed the in vivo expressional changes. In rescue studies, anti-microRNA-1 boosted Pim-1 and Bcl-2 expression and promoted cardiomyocyte and cardiac progenitor cell survival under high glucose conditions. Similarly, transfection with Pim-1 plasmid prevented high glucose–induced cardiomyocyte and cardiac progenitor cell apoptosis. Finally, a single intravenous injection of human Pim-1 via cardiotropic serotype-9 adeno-associated virus (1×1010 or 5×1010 plaque-forming units per animal) at 4 weeks after diabetes induction led to sustained cardiac overexpression of Pim-1 and improved diastolic function and prevented left ventricular dilation and failure. Histological examination showed reduced cardiomyocyte apoptosis and fibrosis in association with increased c-kit+ cells and cardiomyocyte proliferation, whereas molecular analysis confirmed activation of the prosurvival pathway and conservation of sarcoendoplasmic reticulum Ca2+-ATPase and α-myosin heavy chain in Pim-1–treated hearts.
Conclusions: Pim-1 downregulation contributes in the pathogenesis of diabetic cardiomyopathy. Systemic delivery of human Pim-1 via cardiotropic adeno-associated virus serotype-9 represents a novel and effective approach to treat diabetic cardiomyopathy.
- Received December 13, 2010.
- Revision received March 23, 2011.
- Accepted March 25, 2011.
- © 2011 American Heart Association, Inc.