Overexpression of TGFβ1 by adeno-associated virus type-2 vector protects myocardium from ischemia-reperfusion injury

Transforming growth factor beta(1) (TGF beta(1)) has been purported to protect tissues from ischemia - reperfusion (I-R) injury. This study was designed to examine if overexpression of TGF beta(1) using adeno-associated virus type 2 (AAV) protects cardiomyocytes from reoxygenation injury. TGF beta(1) was overexpressed in cultured HL-1 mouse cardiomyocytes by transfection with AAV/TGF beta(Latent)(1) or with AAV/TGF beta(ACT)(1) (active TGF beta(1)). TGF beta(1) upregulation reduced cardiomyocyte apoptosis and necrosis induced by 24 h of hypoxia followed by 3 h of reoxygenation concomitant with reduction in reactive oxygen species release, activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and NF-kappa B expression. Transfection with AAV/TGF beta(ACT)(1) was superior to that with AAV/TGF beta(Latent)(1). To determine if AAV/TGF beta(ACT)(1) upregulation in vivo would induce cardioprotection from I-R injury, rat hearts were injected with AAV/TGF beta(ACT)(1) or phosphate-buffered saline (PBS). Six weeks later, TGF beta(ACT)(1) was upregulated throughout the myocardium. Following I-R, AAV/TGF beta(ACT)(1)-overexpressing rats had much smaller infarct size (P < 0.01 vs PBS group), which was also related to reduced activation of NADPH oxidase and NF-kappa B, and lower levels of malondialdehyde in I-R tissues. These data demonstrate that overexpression of TGF beta(1) by AAV can protect cardiac tissues from reperfusion injury, possibly via antioxidant mechanism. These findings suggest potential of TGF beta(ACT)(1) gene therapy for cardioprotection from I-R injury.