cyclic-gmp and arginyl-glycyl-aspartic-acid

Cardiac remodeling involves the accumulation of extracellular matrix (ECM) proteins including fibronectin (FN). FN contains RGD motifs that bind integrins at DDX sequences allowing signaling from the ECM to the nucleus. We noted that the natriuretic peptide receptor A (NPR-A) sequence contains both RGD and DDX sequences. The goal of the current investigation was to determine potential interactions between FN and NPR-A on BNP induction of cGMP in cultured human cardiac fibroblasts (CFs). Further, we sought to determine whether a Mayo designed NPR-A specific RGD peptide could modify this interaction. Here we reconfirm the presence of all three natriuretic peptide receptors (NPR) in CFs. CFs plated on FN demonstrated a pronounced increase in cGMP production to BNP compared to non-coated plates. This production was also enhanced by the NPR-A specific RGD peptide, which further augmented FN associated cGMP production. Addition of HS-142-1, a NPR-A/B antagonist, abrogated the responses of BNP to both FN and the NPR-A specific RGD peptide. Finally, we defined a possible role for the NPR-C through non-cGMP mechanisms in mediating the anti-proliferative actions of BNP in CFs where the NPR-C antagonist cANF 4-28 but not HS-142-1 blocked BNP-mediated inhibition of proliferation of CFs. We conclude that NPR-A interacts with components of the ECM such as FN to enhance BNP activation of cGMP and that a small NPR-A specific RGD peptide augments this action of BNP with possible therapeutic implications. Lastly, the NPR-C may also have a role in mediating anti-proliferative actions of BNP in CFs.

Topics: Cell Proliferation; Cells, Cultured; Cyclic GMP; Fibroblasts; Fibronectins; Guanylate Cyclase; Humans; Myocardium; Natriuretic Peptide, Brain; Oligopeptides; Receptors, Atrial Natriuretic Factor

Peptides containing the extracellular matrix peptide cell attachment sequence RGD possess potent, endothelium-dependent vasorelaxant properties. In the present study, the ability of RGD-containing peptides to cause vasorelaxation in the presence and absence of a functional endothelium was examined in rat aortic rings along with the ability of RGD-containing peptides to increase cGMP production in these vessels. The active RGD-containing peptide GRGDNP induced rapid relaxation in endothelium-intact, norepinephrine contracted rat aortic rings. When the endothelium was removed, RGD-containing peptides produced a slow relaxation of contracted rings which took approx. 40 min to reach maximum relaxation. Control RGD peptides were without effect either in the presence or absence of a functional endothelium. While acetylcholine and sodium nitroprusside stimulated cGMP production in endothelium-intact and denuded aortic segments, neither the control RGD peptide nor the active GRGDNP increased cGMP in these vessels when compared to controls upon either short (30 s) or long (45 min) incubation times. These data indicate that relaxations of rat aortic rings in response to RGD-containing peptides occur both in the presence and absence of an intact endothelium and that cGMP is likely not the sole mediator of these responses.

Topics: Acetylcholine; Amino Acid Sequence; Animals; Aorta, Thoracic; Cyclic GMP; Endothelium, Vascular; Male; Muscle, Smooth, Vascular; Nitroprusside; Norepinephrine; Oligopeptides; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Time Factors; Vasodilation; Vasodilator Agents