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Selective inhibitors of cardiac ADPR cyclase as novel anti-arrhythmic compounds.

Kannt A, Sicka K, Kroll K, Kadereit D, Gögelein H - Naunyn Schmiedebergs Arch. Pharmacol. (2012)

Bottom Line: Via its interaction with the ryanodine receptor Ca(2+) channel in the heart, cADPR may exert arrhythmogenic activity.Using a high-throughput screening approach on cardiac sarcoplasmic reticulum membranes isolated from pig and rat and nicotinamide hypoxanthine dinuleotide as a surrogate substrate, we have identified potent and selective inhibitors of an intracellular, membrane-bound cardiac ADPRC that are different from the two known mammalian ADPRCs, CD38 and CD157/Bst1.Inhibition of cardiac ADPRC prevents Ca(2+) overload-induced spontaneous depolarizations and ventricular fibrillation and may thus provide a novel therapeutic principle for the treatment of cardiac arrhythmias.

View Article: PubMed Central - PubMed

Affiliation: Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, G877, 65926 Frankfurt am Main, Germany. aimo.kannt@sanofi.com

ABSTRACT
ADP-ribosyl cyclases (ADPRCs) catalyse the conversion of nicotinamide adenine dinucleotide to cyclic adenosine diphosphoribose (cADPR) which is a second messenger involved in Ca(2+) mobilisation from intracellular stores. Via its interaction with the ryanodine receptor Ca(2+) channel in the heart, cADPR may exert arrhythmogenic activity. To test this hypothesis, we have studied the effect of novel cardiac ADPRC inhibitors in vitro and in vivo in models of ventricular arrhythmias. Using a high-throughput screening approach on cardiac sarcoplasmic reticulum membranes isolated from pig and rat and nicotinamide hypoxanthine dinuleotide as a surrogate substrate, we have identified potent and selective inhibitors of an intracellular, membrane-bound cardiac ADPRC that are different from the two known mammalian ADPRCs, CD38 and CD157/Bst1. We show that two structurally distinct cardiac ADPRC inhibitors, SAN2589 and SAN4825, prevent the formation of spontaneous action potentials in guinea pig papillary muscle in vitro and that compound SAN4825 is active in vivo in delaying ventricular fibrillation and cardiac arrest in a guinea pig model of Ca(2+) overload-induced arrhythmia. Inhibition of cardiac ADPRC prevents Ca(2+) overload-induced spontaneous depolarizations and ventricular fibrillation and may thus provide a novel therapeutic principle for the treatment of cardiac arrhythmias.

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a Formation of cIDPR by purified cardiac sarcoplasmic reticulum vesicles. Filled circles, rat cardiac SR; open circles, pig cardiac SR (n = 16 each). Specific IDPR cyclase activity was estimated as 6.5 nmol min−1 mg protein−1 for rat and 0.63 nmol min−1 mg protein−1 for pig SR. b Effect of Zn2+ ions on the activity of rat cardiac SR ADPR cyclase, CD38 and A. californica ADPR cyclase. For the rat cardiac ADPR cyclase, the dashed line denotes the IC50 value that was determined as 320 ± 55 μM (n = 3). c In-gel activity assay of partially purified ADPR cyclase from rat cardiac SR vesicles. Activities in aqueous solutions of the samples in lanes 2, 3 and 4 corresponded to 21, 15 and 4 RFU/s, respectively
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Fig1: a Formation of cIDPR by purified cardiac sarcoplasmic reticulum vesicles. Filled circles, rat cardiac SR; open circles, pig cardiac SR (n = 16 each). Specific IDPR cyclase activity was estimated as 6.5 nmol min−1 mg protein−1 for rat and 0.63 nmol min−1 mg protein−1 for pig SR. b Effect of Zn2+ ions on the activity of rat cardiac SR ADPR cyclase, CD38 and A. californica ADPR cyclase. For the rat cardiac ADPR cyclase, the dashed line denotes the IC50 value that was determined as 320 ± 55 μM (n = 3). c In-gel activity assay of partially purified ADPR cyclase from rat cardiac SR vesicles. Activities in aqueous solutions of the samples in lanes 2, 3 and 4 corresponded to 21, 15 and 4 RFU/s, respectively

Mentions: Sarcoplasmic reticulum vesicles prepared from rat or pig hearts were found to contain ADPR cyclase activity measured using NHD as a surrogate substrate (Fig. 1a), as previously described by Meszaros et al. (1997) and Xie et al. (2005). Unlike CD38, the cardiac SR enzyme was determined to be inhibited by Zn2+ (Fig. 1b) showing that the cardiac protein is different from the known mammalian ADPR cyclases, CD38 and Bst1/CD157, that are both activated by Zn2+ (Hirata et al. 1994; Xie et al. 2005). In an in-gel activity assay with partially purified rat heart ADPR cyclase, a single fluorescent band corresponding to an apparent molecular weight of approximately 35 kDa was observed (Fig. 1c), again in line with previous observations (Xie et al. 2005).Fig. 1


Selective inhibitors of cardiac ADPR cyclase as novel anti-arrhythmic compounds.

Kannt A, Sicka K, Kroll K, Kadereit D, Gögelein H - Naunyn Schmiedebergs Arch. Pharmacol. (2012)

a Formation of cIDPR by purified cardiac sarcoplasmic reticulum vesicles. Filled circles, rat cardiac SR; open circles, pig cardiac SR (n = 16 each). Specific IDPR cyclase activity was estimated as 6.5 nmol min−1 mg protein−1 for rat and 0.63 nmol min−1 mg protein−1 for pig SR. b Effect of Zn2+ ions on the activity of rat cardiac SR ADPR cyclase, CD38 and A. californica ADPR cyclase. For the rat cardiac ADPR cyclase, the dashed line denotes the IC50 value that was determined as 320 ± 55 μM (n = 3). c In-gel activity assay of partially purified ADPR cyclase from rat cardiac SR vesicles. Activities in aqueous solutions of the samples in lanes 2, 3 and 4 corresponded to 21, 15 and 4 RFU/s, respectively
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3367138&req=5

Fig1: a Formation of cIDPR by purified cardiac sarcoplasmic reticulum vesicles. Filled circles, rat cardiac SR; open circles, pig cardiac SR (n = 16 each). Specific IDPR cyclase activity was estimated as 6.5 nmol min−1 mg protein−1 for rat and 0.63 nmol min−1 mg protein−1 for pig SR. b Effect of Zn2+ ions on the activity of rat cardiac SR ADPR cyclase, CD38 and A. californica ADPR cyclase. For the rat cardiac ADPR cyclase, the dashed line denotes the IC50 value that was determined as 320 ± 55 μM (n = 3). c In-gel activity assay of partially purified ADPR cyclase from rat cardiac SR vesicles. Activities in aqueous solutions of the samples in lanes 2, 3 and 4 corresponded to 21, 15 and 4 RFU/s, respectively
Mentions: Sarcoplasmic reticulum vesicles prepared from rat or pig hearts were found to contain ADPR cyclase activity measured using NHD as a surrogate substrate (Fig. 1a), as previously described by Meszaros et al. (1997) and Xie et al. (2005). Unlike CD38, the cardiac SR enzyme was determined to be inhibited by Zn2+ (Fig. 1b) showing that the cardiac protein is different from the known mammalian ADPR cyclases, CD38 and Bst1/CD157, that are both activated by Zn2+ (Hirata et al. 1994; Xie et al. 2005). In an in-gel activity assay with partially purified rat heart ADPR cyclase, a single fluorescent band corresponding to an apparent molecular weight of approximately 35 kDa was observed (Fig. 1c), again in line with previous observations (Xie et al. 2005).Fig. 1

Bottom Line: Via its interaction with the ryanodine receptor Ca(2+) channel in the heart, cADPR may exert arrhythmogenic activity.Using a high-throughput screening approach on cardiac sarcoplasmic reticulum membranes isolated from pig and rat and nicotinamide hypoxanthine dinuleotide as a surrogate substrate, we have identified potent and selective inhibitors of an intracellular, membrane-bound cardiac ADPRC that are different from the two known mammalian ADPRCs, CD38 and CD157/Bst1.Inhibition of cardiac ADPRC prevents Ca(2+) overload-induced spontaneous depolarizations and ventricular fibrillation and may thus provide a novel therapeutic principle for the treatment of cardiac arrhythmias.

View Article: PubMed Central - PubMed

Affiliation: Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, G877, 65926 Frankfurt am Main, Germany. aimo.kannt@sanofi.com

ABSTRACT
ADP-ribosyl cyclases (ADPRCs) catalyse the conversion of nicotinamide adenine dinucleotide to cyclic adenosine diphosphoribose (cADPR) which is a second messenger involved in Ca(2+) mobilisation from intracellular stores. Via its interaction with the ryanodine receptor Ca(2+) channel in the heart, cADPR may exert arrhythmogenic activity. To test this hypothesis, we have studied the effect of novel cardiac ADPRC inhibitors in vitro and in vivo in models of ventricular arrhythmias. Using a high-throughput screening approach on cardiac sarcoplasmic reticulum membranes isolated from pig and rat and nicotinamide hypoxanthine dinuleotide as a surrogate substrate, we have identified potent and selective inhibitors of an intracellular, membrane-bound cardiac ADPRC that are different from the two known mammalian ADPRCs, CD38 and CD157/Bst1. We show that two structurally distinct cardiac ADPRC inhibitors, SAN2589 and SAN4825, prevent the formation of spontaneous action potentials in guinea pig papillary muscle in vitro and that compound SAN4825 is active in vivo in delaying ventricular fibrillation and cardiac arrest in a guinea pig model of Ca(2+) overload-induced arrhythmia. Inhibition of cardiac ADPRC prevents Ca(2+) overload-induced spontaneous depolarizations and ventricular fibrillation and may thus provide a novel therapeutic principle for the treatment of cardiac arrhythmias.

Show MeSH
Related in: MedlinePlus