Gene transfer of a novel vasoactive natriuretic peptide stimulates cGMP and lowers blood pressure in mice

Dendroaspis natriuretic peptide (DNP) is a recently described peptide produced by Dendroaspis angusticeps with structural and functional similarities to mammalian natriuretic peptides. These similarities suggest a potential role for DNP in cardiovascular therapeutics. To determine the physiological effects of chronic delivery of DNP, a gene transfer approach using first generation adenoviral vectors was utilized. Although the gene for DNP has not been cloned in any species, the peptide sequence in the snake is known. Preferred mammalian codons for snake DNP were cloned downstream of either the leader sequence (referred to as pBDNP-1) or prepropeptide sequence of human brain natriuretic peptide (BNP) cDNA (referred to as pBDNP-2). Transfections with pBDNP-1 or pBDNP-2 resulted in expected forms of chimeric DNP (cDNP) in cell lysates and conditioned media. Functional studies demonstrated the ability of both forms of cDNP within conditioned media to stimulate cGMP production in human vascular smooth muscle cells (hVSMC). Expressed cDNP inhibited hVSMC proliferation and stimulated vasorelaxation in a similar fashion. To investigate the chronic physiological effects of administration of cDNP, an adenoviral vector expressing cDNP (Ad-BDNP) was generated. Intravenous delivery of Ad-BDNP in mice resulted in dose-dependent systemic expression of cDNP. The highest level of expression was associated with consistent elevation of its presumed second messenger (cGMP) for 21 days but with transient lowering of systolic blood pressure in normotensive mice. This study demonstrates the biological features of the expression of the xenogenic peptide DNP.