Dilated Cardiomyopathy in Transgenic Mice With Cardiac-Specific Overexpression of Tumor Necrosis Factor-α

Abstract

The failing human heart expresses tumor necrosis factor-α (TNF-α). However, its pathophysiological significance is not clear. We previously reported that robust overexpression of TNF-α in the murine heart causes lethal myocarditis. In this study, we modified the transgene to reduce the production of TNF-α by preserving the destabilizing sequence in TNF-α cDNA. Expression was driven by the murine α-myosin heavy chain promoter. Use of this modified construct allowed us to establish a murine transgenic line (TG). TG offspring were examined at 6, 12, and 24 weeks. All showed a significantly higher heart weight–to–body weight ratio. Northern blot analysis confirmed the expression of transgene in the heart, and enzyme-linked immunosorbent assay demonstrated the presence of TNF-α protein. The TG heart demonstrated a mild, diffuse, lymphohistiocytic interstitial inflammatory infiltrate. Cardiomyocyte necrosis and apoptosis were present but not abundant. Magnetic resonance imaging showed that the TG heart...