Atrial Natriuretic Peptide Enhances IL-1β-Stimulated Nitric Oxide Production in Cultured Rat Vascular Smooth Muscle Cells

Abstract

Objective: To elucidate the effect of atrial natriuretic peptide (ANP) on cytokine-induced nitric oxide (NO) production, we examined whether ANP affects IL-1β-stimulated NO production and inducible NO synthase (iNOS) mRNA expression in cultured rat vascular smooth muscle cells (VSMC). Methods: VSMC were incubated with test agents for 24 h. The nitrite concentration of the culture medium, a stable-end product of NO, was measured by the column reduction method. NOS mRNA expression was analyzed by Northern blotting. The intracellular cAMP content was measured by enzyme immunoassay. cAMP-dependent kinase (PKA) activity was determined by a PKA assay system. Results: IL-1β stimulated nitrite production in VSMC. ANP (10 nM to 1 mM) enhanced the nitrite production and iNOS mRNA expression in the presence of IL-1β. Both 8-bromo-guanosine 3′,5′-cyclic monophosphate (8-br-cGMP) and dibutylyl adenosine 3′,5′-cyclic monophate enhanced IL-1β-induced nitrite production. The effects of these two nucleotide donors on the nitrite production were not additive, suggesting a common pathway. KT 5720, an inhibitor of PKA, abolished the enhancement of nitrite production by ANP and 8-br-cGMP, while KT 5823, an inhibitor of cGMP-dependent protein kinase, did not inhibit the enhancement. In the in vitro assay 8-br-cGMP increased PKA activity. Conclusions: ANP and cGMP enhanced IL-1β-induced NO production in VSMC. PKA rather than PKG may be involved in the enhancement.

Sildenafil stimulates the expression of gaseous monoxide-generating enzymes in vascular smooth muscle cells via distinct signaling pathways

“…In fact, incubation of SMCs with the PKA inhibitor KT 5720 abolishes the sildenafil-mediated increase in NO synthesis in cytokine-exposed cells. These results are in-line with earlier reports showing that PKA mediates the augmentation of cytokine-induced NO generation in vascular SMCs by activators of guanylate cyclase [36,37]. Furthermore, the ability of KT 5720 to suppress NO synthesis following cytokine treatment is consistent with a previous study showing a critical role for PKA in mediating the induction of iNOS by cytokines [38].…”

The Anti-Platelet Agent, Ticlopidine, Upregulates Interleukin-1-Beta-Stimulated Nitric Oxide Production in Cultured Rat Vascular Smooth Muscle Cells

“…In cultured rat VSMC, we found that cGMP-generating agents, including ANP, could enhance the IL-1β-induced NO production through activation of protein kinase A [12]. In the present study, ticlopidine increased both cyclic nucleotides.…”

“…We also reported that erythropoietin (EPO) inhibited the iNOS mRNA expression and protein via activation of protein kinase C [9, 10]. Conversely, both atrial natriuretic peptide and cGMP enhanced IL-1β-induced NO production in VSMC, possibly through activation of cAMP-dependent protein kinase [11, 12]. With regard to cyclic nucleotides, cyclic 3′,5′-adenosine monophosphate (cAMP) is known to have a potency to stimulate iNOS mRNA expression and NO production [13, 14, 15].…”

Pharmacological Intervention for Prevention of Left Ventricular Remodeling and Improving Prognosis in Myocardial Infarction

“…64 ANP was first identified as a diuretic/natriuretic and vasodilating hormone, 65 but subsequent studies revealed that ANP has various cardioprotective effects such as antiapoptosis, antifibrosis, and antihypertrophy not only as circulating hormones but also as local autocrine and/or paracrine factors. 66 -68 ANP has been reported to accelerate nitric oxide generation, 69,70 which mediates late preconditioning. Furthermore, ANP activates the reperfusion injury salvage kinase, which acts like ischemic preconditioning and postconditioning.…”