Human recombinant chromogranin A-derived vasostatin-1 mimics preconditioning via an adenosine/nitric oxide signaling mechanism

Abstract

The acidic protein chromogranin A (CgA) is the precursor of several regulatory peptides generated by specific proteolytic processes. Human recombinant CgA NH(2)-terminal fragment STA-CgA(1-78) (hrSTA-CgA(1-78)), containing vasostatin-1 (CgA(1-76)) domain, exerts a negative inotropic effect and counteracts the beta-adrenergic positive inotropic effect on the rat heart. We hypothesized an involvement of nitric oxide (NO)-dependent pathway in both cardiodepression and cardioprotection by hrSTA-CgA(1-78). We also hypothesized an involvement of adenosine A(1) receptor and protein kinase C (PKC) in cardioprotection by hrSTA-CgA(1-78). Therefore, we evaluated whether 1) the cardioinhibition mediated by hrSTA-CgA(1-78) involves the G(i/o) proteins/NO-dependent signal transduction cascade, 2) hrSTA-CgA(1-78) induces ischemic preconditioning-like protective effects on the myocardium, and 3) inhibition of NO synthase (NOS), adenosine A(1) receptor, or PKC affects hrSTA-CgA(1-78) protection. Using the isolated rat heart, we found that the reduction of left ventricular pressure (LVP), rate-pressure product, and maximal values of the first derivative of LVP elicited by hrSTA-CgA(1-78) at 33 nM is abolished by blocking G(i/o) proteins with pertussis toxin, scavenging NO with hemoglobin, and blocking NOS activity with N(G)-monomethyl-l-arginine or N(5)-(iminoethyl)-l-ornithine, soluble guanylate cyclase with 1H-[1,2,4]oxadiazole-[4,4-a]quinoxalin-1-one, and protein kinase (PKG) with KT5823. Data suggest the involvement of the G(i/o) proteins/NO-cGMP-PKG pathway in the hrSTA-CgA(1-78)-dependent cardioinhibition. When given before 30 min of ischemia, hrSTA-CgA(1-78) significantly reduced the size of the infarct from 64 +/- 4 to 32 +/- 3% of the left ventricular mass. This protective effect was abolished by either NOS inhibition or PKC blockade and was attenuated, but not suppressed, by the blockade of A(1) receptors. These results suggest that hrSTA-CgA(1-78) activity triggers two different pathways: one of these pathways is mediated by A(1) receptors, and the other is mediated by NO release. As with repeated brief preconditioning ischemia, hrSTA-CgA(1-78) may be considered a stimulus strong enough to trigger both pathways, which may converge on PKC.

The catecholamine release-inhibitory peptide catestatin (chromogranin A344-364) modulates myocardial function in fish

“…In the present work, we report that the NO-cGMP pathway is involved in the negative inotropism induced by CST (Fig.7), as it is abolished by pretreatment with either the NOS inhibitor L-NMMA or the sGC blocker ODQ. This agrees with the involvement of this signaling pathway in the CSTdependent cardiosuppression observed in frog and rat Mazza et al, 2008), and with the NO-cGMP-dependent negative inotropism induced by VS-1 in both eel and rat (Imbrogno et al, 2004;Cappello et al, 2007). Although detailed molecular mechanisms are not yet completely established, the finding that the cardiotropic action of CST in at least three classes of vertebrates involves converging transduction cascades, underlines the key role of some mediators (i.e.…”

Catestatin reduces myocardial ischaemia/reperfusion injury: involvement of PI3K/Akt, PKCs, mitochondrial KATP channels and ROS signalling

“…Risk area and infarct-size assessed in hearts perfused with only inhibitors (groups [8][9][10][11][12] were similar to those observed in I/R control group (Fig.2B). This lack of effects on I/R injury has been already reported [14,35,39,[41][42][43][44].…”

“…For instance, the N-terminal VS-1 induced a preconditioning-like effect via adenosine/nitric oxide (NO) protective signalling, reducing the extension of myocardial infarction in the rat heart [10].…”

Catecholamines, cardiac natriuretic peptides and chromogranin A: evolution and physiopathology of a ‘whip-brake’ system of the endocrine heart

“…By contrast, neither the N-nor the C-terminal group of VS-1 is critical for the cardiosuppressant effect of the peptide . Importantly, we demonstrated in the rat heart that VS-1 also exerts cardioprotection by reducing the effects of ischemia in a way that mimics ischemic preconditioning (Cappello et al, 2007). On the whole, the cardiotropic and vasoactive properties of CgA-derived VS, together with their ischemic preconditioning-like influence, suggest that these peptides function as homeostatic stabilizers of the cardiovascular system, particularly under conditions of stress (i.e.…”

“…Only in the eel are cholinergic M1 receptors also involved. In both eel and frog, the VS-1-induced negative inotropism is also abolished by the inhibition of either potassium or calcium fluxes, emphasizing the relevance of spatially restricted membrane domains in which receptors, modulatory proteins and ion channels may be functionally coupled Imbrogno et al, 2004;Cappello et al, 2007). As, in cardiomyocytes, the above signaling molecules are clustered with their substrates in specialized membrane microenvironments -the caveolae -these were proposed as the action sites of the peptide [for references, see Tota et al (Tota et al, 2007a)].…”