Acta Pharmacologica Sinica (2009) 30: 1253–1261; doi: 10.1038/aps.2009.114; published online 17 August 2009

Aim: Overexpression of human tissue kallikrein (HK), mediated by recombinant adeno-associated virus (rAAV), decreased blood pressure in spontaneous hypertensive rats (SHRs) and reduced injury to the heart, aorta and kidney.  In this study, we used both an in vivo animal model and in vitro cell culture system to investigate whether rAAV-mediated HK gene therapy protects against organ damage by inhibiting cell apoptosis.

Methods: rAAV encoding HK (rAAV-HK) or LacZ (rAAV-lacZ) were delivered as a control to spontaneously hypertensive rats (SHRs) and cultured human embryonic kidney (HEK) 293 cells. 

Results: Treatment with rAAV-HK decreased cell apoptosis in the target organs of SHRs and also inhibited lipopolysaccharide (LPS)-induced HEK 293 apoptosis.  The rAAV-HK delivery system also increased the levels of apoptosis-inhibiting proteins bcl-2 and bcl-x_L, and decreased the level of Bax and the activity of caspase 3, two promoters of apoptosis.  In addition to its role in the inhibition of apoptosis, rAAV-HK also activated the cell survival and proliferation signaling pathways ERK1/2 and PI3K/AKT. 

Conclusion: rAAV-mediated HK gene delivery has multiple therapeutic possibilities for treating hypertension, not only by decreasing blood pressure, but also by directly inhibiting end-organ damage. 

Keywords: kallikrein; recombinant adeno-associated virus; gene therapy; hypertension; apoptosis; target organs injuries