Effects of SEA0400 on Mutant NCX1.1 Na+-Ca2+ Exchangers with Altered Ionic Regulation

Bouchard, Ron A.; Omelchenko, Alexander; Le, Huy; Choptiany, Platon; Matsuda, Takehisa; Baba, Akemichi; Takahashi, Keiichi; Nicoll, Debora A.; Philipson, Kenneth D.; Hnatowich, Mark; Hryshko, Larry V.

doi:10.1124/mol.65.3.802

Cited by 36 publications

(29 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These data suggest that the inhibitory effect of SN-6 is related to the kinetics of I 1 inactivation. Similar results have also been observed in other benzyloxyphenyl derivatives, including KB-R7943 and SEA0400 (Bouchard et al, 2004;Iwamoto et al, 2004). K229Q apparently works as a constitutively active exchanger, as do Y224W/Y226W/Y228W/ Y231W (termed XIP-4YW) and ⌬229-232, which were used in the above-cited reports.…”

Section: Discussionsupporting

confidence: 63%

“…This possibility received support from the evidence that benzyloxyphenyl derivatives had hypersensitivities to N1-F223E, which are able to very quickly enter an I 1 inactive state (Bouchard et al, 2004;Iwamoto et al, 2004). Therefore, we speculate that the interaction of benzyloxyphenyl derivatives with the exchanger probably stabilizes the I 1 inactive state or accelerates the rate of entry into an I 1 inactive state.…”

Section: Ncx Inhibition By Sn-6 53mentioning

confidence: 58%

See 1 more Smart Citation

The Exchanger Inhibitory Peptide Region-Dependent Inhibition of Na+/Ca2+ Exchange by SN-6 [2-[4-(4-Nitrobenzyloxy)benzyl]thiazolidine-4-carboxylic Acid Ethyl Ester], a Novel Benzyloxyphenyl Derivative

Iwamoto

Inoue²,

Ito³

et al. 2004

Molecular Pharmacology

102

View full text Add to dashboard Cite

We investigated the properties and interaction domains of Ca2ϩ efflux (i.e., the forward mode) in NCX1-transfected fibroblasts. SN-6 was 3-to 5-fold more inhibitory to 45 Ca 2ϩ uptake in NCX1 (IC 50 ϭ 2.9 M) than to that in NCX2 or NCX3 but not to that in NCKX2. We searched for regions that may form the SN-6 receptor by NCX1/ NCX3-chimeric analyses and determined that amino acid regions 73 to 108 and 193 to 230 in NCX1 are mostly responsible for the differential drug response between NCX1 and NCX3. Further sitedirected mutagenesis revealed that double substitutions of Val227 and Tyr228 in NCX1, which exist within the exchanger inhibitory peptide (XIP) region, mimicked the different drug response. In addition, F213R, G833C, and N839A mutations in NCX1 resulted in loss of drug sensitivity. Exchangers with mutated XIP regions, which display either undetectable or accelerated Na ϩ -dependent inactivation, had markedly reduced sensitivity or hypersensitivity to SN-6, respectively. Cell ATP depletion enhanced the inhibitory potency of SN-6. Therefore, SN-6 at lower doses (IC 50 ϭ 0.63 M) potently protected against hypoxia/reoxygenation-induced cell damage in renal tubular cells overexpressing NCX1, suggesting that this drug predominantly works under hypoxic/ischemic conditions. These properties of SN-6, which may be derived from its interaction with the XIP region, are advantageous to developing it as a new anti-ischemic drug.

show abstract

Section: Discussionsupporting

confidence: 63%

Section: Ncx Inhibition By Sn-6 53mentioning

confidence: 58%

The Exchanger Inhibitory Peptide Region-Dependent Inhibition of Na+/Ca2+ Exchange by SN-6 [2-[4-(4-Nitrobenzyloxy)benzyl]thiazolidine-4-carboxylic Acid Ethyl Ester], a Novel Benzyloxyphenyl Derivative

Iwamoto

Inoue²,

Ito³

et al. 2004

Molecular Pharmacology

102

View full text Add to dashboard Cite

show abstract

“…Furthermore, we evaluated the effects of YM-244769 on NCX1 mutant (i.e., D447V/D498I) displaying a phenotype for a low regulatory Ca 2ϩ affinity, but we could not detect a significant relationship between the drug sensitivity and I 2 inactivation. These properties have also been observed in other benzyloxyphenyl derivatives (Bouchard et al, 2004;Iwamoto et al, 2004a,b).…”

Section: Neuroprotection By Ym-244769 2081supporting

confidence: 50%

“…In existing benzyloxyphenyl NCX inhibitors, reverse mode-selectivity is commonly observed under unidirectional ionic conditions (Iwamoto et al, 1996(Iwamoto et al, , 2004aWatano et al, 1996;Bouchard et al, 2004). On the other hand, other data have shown that both SEA0400 and KB-R7943 equally block outward and inward exchange cur- , and NCX3 isoforms in SH-SY5Y and LLC-PK 1 cells, microsomes (30 g) from cells or from mouse brain were subjected to immunoblot analyses with specific antibodies against the isoforms.…”

Section: Discussionmentioning

confidence: 99%

YM-244769, a Novel Na+/Ca2+ Exchange Inhibitor That Preferentially Inhibits NCX3, Efficiently Protects against Hypoxia/Reoxygenation-Induced SH-SY5Y Neuronal Cell Damage

Iwamoto¹,

Kita²

2006

Molecular Pharmacology

View full text Add to dashboard Cite

We investigated the pharmacological properties and interaction domains of N- (3-aminobenzyl)-6-{4-[(3-fluorobenzyl)oxy]phenoxy} nicotinamide (YM-244769), a novel potent Na ϩ /Ca 2ϩ exchange (NCX) inhibitor, using various NCX-transfectants and neuronal and renal cell lines. YM-244769 preferentially inhibited intracellular Na ϩ -dependent 45 Ca 2ϩ uptake via NCX3 (IC 50 ϭ 18 nM); the inhibition was 3.8-to 5.3-fold greater than for the uptake via NCX1 or NCX2, but it did not significantly affect extracellular Na ϩ -dependent 45 Ca 2ϩ efflux via NCX isoforms. We searched for interaction domains with YM-244769 by NCX1/NCX3-chimeric analysis and determined that the ␣-2 region in NCX1 is mostly responsible for the differential drug response between NCX1 and NCX3. Further cysteine scanning mutagenesis in the ␣-2 region identified that the mutation at Gly833 markedly reduced sensitivity to YM-244769. Mutant exchangers that display either undetectable or accelerated Na ϩ -dependent inactivation, had markedly reduced sensitivity or hypersensitivity to YM-244769, respectively. YM-244769, like 2-[2-[4-(4-nitrobenzyloxyl)phenyl]ethyl]isothiourea methanesulfonate (KB-R7943), protected against hypoxia/reoxygenation-induced cell damage in neuronal SH-SY5Y cells, which express NCX1 and NCX3, more efficiently than that in renal LLC-PK 1 cells, which exclusively express NCX1, whereas 2-[4-(4-nitrobenzyloxy)benzyl]thiazolidine-4-carboxylic acid ethyl ester (SN-6) suppressed renal cell damage to a greater degree than neuronal cell damage. These protective potencies consistently correlated well with their inhibitory efficacies for the Ca 2ϩ uptake via NCX isoforms existing in the corresponding cell lines. Antisense knockdown of NCX1 and NCX3 in SH-SY5Y cells confirmed that NCX3 contributes to the neuronal cell damage more than NCX1. Thus, YM-244769 is not only experimentally useful as a NCX inhibitor that preferentially inhibits NCX3, but also has therapeutic potential as a new neuroprotective drug.

show abstract

“…Overall, the major inhibitory effects of SEA0400 require the presence of intracellular Na ϩ and generally follow the preponderance of the I 1 inactive state. Similar conclusions have been reached based on the evaluation of mutant Na ϩ -Ca 2ϩ exchangers with altered I 1 inactivation (Bouchard et al, 2004;Iwamoto et al, 2004).…”

supporting

confidence: 62%

Inhibitory Profile of SEA0400 [2-[4-[(2,5-Difluorophenyl)methoxy]phenoxy]-5-ethoxyaniline] Assessed on the Cardiac Na+-Ca2+ Exchanger, NCX1.1

Lee

Visen²,

Dhalla³

et al. 2004

The Journal of Pharmacology and Experimental Therapeutics

Self Cite

View full text Add to dashboard Cite

SEA0400 (2-[4-[(2,5-difluorophenyl)methoxy]phenoxy]-5-ethoxyaniline) has recently been described as a potent and selective inhibitor of Na ϩ -Ca 2ϩ exchange in cardiac, neuronal, and renal preparations. The inhibitory effects of SEA0400 were investigated on the cloned cardiac Na ϩ -Ca 2ϩ exchanger, NCX1.1, expressed in Xenopus laevis oocytes to gain insight into its inhibitory mechanism. Na ϩ -Ca 2ϩ exchange currents were measured using the giant excised patch technique using conditions to evaluate both inward and outward currents. SEA0400 inhibited outward Na ϩ -Ca 2ϩ exchange currents with high affinity (IC 50 ϭ 78 Ϯ 15 and 23 Ϯ 4 nM for peak and steady-state currents, respectively). Considerably less inhibitory potency (i.e., micromolar) was observed for inward currents. The inhibitory profile was reexamined after proteolytic treatment of excised patches with ␣-chymotrypsin, a procedure that eliminates ionic regulatory mechanisms. After this treatment, an IC 50 value of 1.2 Ϯ 0.6 M was estimated for outward currents, whereas inward currents became almost insensitive to SEA0400. The inhibitory effects of SEA0400 on outward exchange currents were evident at both high and low concentrations of regulatory Ca 2ϩ , although distinct features were noted. SEA0400 accelerated the inactivation rate of outward currents. Based on paired pulse experiments, SEA0400 altered the recovery of exchangers from the Na ϩ i -dependent inactive state, particularly at higher regulatory Ca 2ϩ i concentrations. Finally, the inhibitory potency of SEA0400 was strongly dependent on the intracellular Na ϩ concentration. Our data confirm that SEA0400 is the most potent inhibitor of the cardiac Na ϩ -Ca 2ϩ exchanger described to date and provide a reasonable explanation for its apparent transport mode selectivity.

show abstract

Effects of SEA0400 on Mutant NCX1.1 Na+-Ca2+ Exchangers with Altered Ionic Regulation

Cited by 36 publications

References 20 publications

The Exchanger Inhibitory Peptide Region-Dependent Inhibition of Na+/Ca2+ Exchange by SN-6 [2-[4-(4-Nitrobenzyloxy)benzyl]thiazolidine-4-carboxylic Acid Ethyl Ester], a Novel Benzyloxyphenyl Derivative

The Exchanger Inhibitory Peptide Region-Dependent Inhibition of Na+/Ca2+ Exchange by SN-6 [2-[4-(4-Nitrobenzyloxy)benzyl]thiazolidine-4-carboxylic Acid Ethyl Ester], a Novel Benzyloxyphenyl Derivative

YM-244769, a Novel Na+/Ca2+ Exchange Inhibitor That Preferentially Inhibits NCX3, Efficiently Protects against Hypoxia/Reoxygenation-Induced SH-SY5Y Neuronal Cell Damage

Inhibitory Profile of SEA0400 [2-[4-[(2,5-Difluorophenyl)methoxy]phenoxy]-5-ethoxyaniline] Assessed on the Cardiac Na+-Ca2+ Exchanger, NCX1.1

Contact Info

Product

Resources

About