A novel contractile phenotype with cardiac transgenic expression of the human P2X
            <sub>4</sub>
            receptor

Hu, Bing; Mei, Qibing; Yao, Xiujuan; Smith, Emily; Barry, William H.; Liang, Bruce T.

doi:10.1096/fj.01-0445fje

Cited by 45 publications

(85 citation statements)

References 26 publications

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“…Similarly, the P2 antagonist pyridoxal phosphate-6-azophenyl-2Ј,4Ј-disulfonic acid (50 M) did not block the 2-meSATP-stimulated increase in myocyte contractility (data not shown). Although more work is needed, the pharmacological features of the P2 agonist-induced contractile response of the chick embryo cardiac myocyte are similar to those of the response in adult rat and mouse cardiac myocytes (11,18). Since the P2X 4 receptor was also detected in these adult mammalian cardiac myocytes, the present data are consistent with the idea that the chick cardiac cell is a potentially good model to investigate the physiological role and biochemical property of the cardiac P2X 4 R.…”

Section: Resultssupporting

confidence: 83%

“…At later time points following the transfection with exogenous cP2X 4 R cDNA, only the 58-kDa receptor protein was present (Fig. 4b), consistent with a more complete glycosylation of the exogenous cP2X 4 R. Only the 58-kDa P2X 4 receptor was detectable in cardiac myocytes isolated from adult wild type mouse and from P2X 4 receptor transgenic mice, which showed an increased receptor-mediated contractility (11). These data suggested that the 58-kDa receptor protein, probably representing the glycosylated P2X 4 receptor, is the final and functional form of the receptor.…”

Section: Resultssupporting

confidence: 58%

“…Further, the increase in myocyte contractility was insensitive to blockade by the P2 antagonist suramin or pyridoxal phosphate-6-azophenyl-2Ј,4Ј-disulfonic acid, as was the P2X 4 receptor-mediated increase in current. Finally, the receptor was expressed in the heart, and its cardiac transgenic overexpression resulted in an increased basal contractility of the intact heart, mediated via the endogenous ATP stimulating the overexpressed P2X 4 receptor (11).…”

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P2X4 Receptor Is a Glycosylated Cardiac Receptor Mediating a Positive Inotropic Response to ATP

Senkler

Yang

et al. 2002

Journal of Biological Chemistry

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Although P2X receptors are suggested to play a role in synaptic neurotransmission, the specific physiological role of each P2X receptor subtype remains largely unknown. We used cultured chick embryo ventricular myocytes as a model to study a potential physiological role of the P2X 4 receptor in mediating the positive inotropic effect of ATP. The chick P2X4 receptor (cP2X 4 R) mRNA was expressed in the heart and the pharmacological features of the ATP-induced positive inotropic response were similar to those of the cP2X 4 R in terms of insensitivity to blockade by known P2 receptor antagonists and the ineffectiveness of adenosine 5-(␣,␤-methylene)triphosphate as an agonist. Treatment of myocytes with antisense oligonucleotides specific to the 5 region of cP2X 4 R abrogated the P2 agonist-stimulated 45 Ca influx. Similarly, antisense oligonucleotide treatment also blocked the 2-methylthio-ATP-stimulated increase in contractile amplitude. The data suggest that the native P2X 4 receptor is involved in mediating the P2 agonist-stimulated response in the heart. In characterizing the biochemical property of the P2X 4 receptor, antibody against cP2X 4 R detected a 44-kDa and a 58-kDa protein in the immunoblot. Inhibition of N-linked glycosylation by tunicamycin converted the 58-kDa protein to the 44-kDa protein, suggesting that the 58-kDa protein was a glycosylated P2X 4 receptor. The nonglycosylated 44-kDa P2X 4 receptor was resistant to various detergent/aqueous extraction, consistent with a role of glycosylation in maintaining its detergent solubility and hydrophilicity. Cross-linking the cell surface proteins with N-hydroxysuccinimide-SS-biotin followed by affinity precipitation with streptavidin-conjugated agarose and subsequent immunoblotting with anti-cP2X 4 R showed that only the glycosylated 58-kDa P2X 4 receptor was expressed on the cell surface, indicating an important role of glycosylation for the receptor's localization on the plasma membrane. These data revealed a novel physiologic function of the P2X 4 receptor and suggested the importance of N-linked glycosylation in its cell surface expression and detergent solubility.P2X receptors are nonselective cation channels gated by ATP (for reviews, see Refs. 1-3). Seven isoforms of P2X receptors identified so far show 35-50% sequence identities based on comparison of the homologous region. Each receptor has two transmembrane domains and a large extracellular loop that contains a number of putative N-glycosylation sites and an ATP binding site. Recent human genome data suggested three additional possible P2X receptors in the human genome, and no P2X counterparts were found in the yeast or Drosophila genome (4). Both N-and C-intracellular termini have been shown to be important in determining the rate of desensitization of the P2X receptor (1-3). Biochemical and elctrophysiological studies suggested homomeric and heteromeric structures, possibly trimer, as the functional form of P2X receptors (1-3, 5-7).In vitro and in vivo studies indicated that P2X receptors ar...

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Section: Resultssupporting

confidence: 83%

Section: Resultssupporting

confidence: 58%

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confidence: 99%

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P2X4 Receptor Is a Glycosylated Cardiac Receptor Mediating a Positive Inotropic Response to ATP

Senkler

Yang

et al. 2002

Journal of Biological Chemistry

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“…cardiac failure; contraction; isoproterenol; purines; adenine nucleotide ATP HAS LONG BEEN DEMONSTRATED to stimulate cardiac myocyte contractility at submicromolar concentrations (3,4,5,18,23). Recent studies show that activation of the P2X receptor subtype of the extracellular ATP receptor family increases the contractility of both cardiac myocytes and the intact heart (3,4,5,9,17,18,23). P2X receptors are ligand-gated ion channels whose activation results in sodium and calcium entry (6,10,12,19,24).…”

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A beneficial role of cardiac P2X₄ receptors in heart failure: rescue of the calsequestrin overexpression model of cardiomyopathy

Yang

Sonin

Jones³

et al. 2004

American Journal of Physiology-Heart and Circulatory Physiology

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influx. Transgenic cardiac overexpression of the human P2X4 receptor showed an in vitro phenotype of enhanced basal contractility. The objective here was to determine the in vivo cardiac physiological role of this receptor. Specifically, we tested the hypothesis that this receptor plays an important role in modulating heart failure progression. Transgenic cardiac overexpression of canine calsequestrin (CSQ) showed hypertrophy, heart failure, and premature death. Crossing the P2X4R mouse with the CSQ mouse more than doubled the lifespan (182 Ϯ 91 days for the binary CSQ/P2X4R mouse, n ϭ 35) of the CSQ mouse (71.3 Ϯ 25.4 days, n ϭ 50, P Ͻ 0.0001). The prolonged survival in the binary CSQ/P2X4R mouse was associated with an improved left ventricular weight-to-body weight ratio and a restored ␤-adrenergic responsiveness. The beneficial phenotype of the binary mouse was not associated with any downregulation of the CSQ level but correlated with improved left ventricular developed pressure and ϮdP/dt. The enhanced cardiac performance was manifested in young binary animals and persisted in older animals. The increased contractility likely underlies the survival benefit from P2X 4 receptor overexpression. An increased expression or activation of this receptor may represent a new approach in the therapy of heart failure. cardiac failure; contraction; isoproterenol; purines; adenine nucleotide ATP HAS LONG BEEN DEMONSTRATED to stimulate cardiac myocyte contractility at submicromolar concentrations (3,4,5,18,23). Recent studies show that activation of the P2X receptor subtype of the extracellular ATP receptor family increases the contractility of both cardiac myocytes and the intact heart (3,4,5,9,17,18,23). P2X receptors are ligand-gated ion channels whose activation results in sodium and calcium entry (6,10,12,19,24). Transgenic overexpression of the P2X 4 subtype of this family of receptor channels exhibits a phenotype of enhanced basal cardiac contractility and output in a working heart model (9). While these data suggest that the P2X receptor subfamily may mediate the effect of ATP on cardiac contractility, the potential cardiac physiological role of this receptor channel is not known. Because of the enhanced cardiac contractile performance of the P2X 4 receptor (P2X 4 R) transgenic mouse, it is possible that P2X 4 receptor overexpression will modulate the progression of heart failure. To test this hypothesis, the P2X 4 R mouse was crossed with the calsequestrin (CSQ) mouse model of cardiac hypertrophy and heart failure. The CSQ model of severe heart failure is generated by overexpressing the sarcoplasmic reticulum (SR) calcium-binding protein CSQ, which disrupts coordinated regulation of calcium release. The model showed a phenotype of hypertrophy that progress to dilated cardiomyopathy, failure, and premature cardiac death by 16 wk of age (2, 11). Here, we tested whether the cardiac P2X 4 R mediates a beneficial effect on the progression to heart failure in the CSQ-overexpressing mouse. We find that the binary CSQ/P2...

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“…[15][16][17][18][19] Interestingly, P2X4R is an important subunit of the native cardiac myocyte P2X receptor, 17 and cardiac-restricted overexpression of P2X4R can induce an enhanced contractile state of the intact heart. 20 More recently, it was found that cardiac overexpression of P2X4R increased cardiac contractility and survival in a model of myocardial infarction-induced cardiac failure. 21 It has therefore emerged as a key factor in the enhancement of cardiac performance.…”

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Expression of P2X4R mRNA and Protein in Rats With Hypobaric Hypoxia-Induced Pulmonary Hypertension

Ohata

Ogata

Nakanishi

et al. 2011

Circ J

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Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp he pulmonary hypertension that develops in hypobaric hypoxia is characterized by structural remodeling of the heart (eg, right ventricular hypertrophy). 1-7 Over the past 20 years or so, various factors and influences, including the adrenergic-receptor system, have been shown to be involved in such cardiovascular remodeling processes. [8][9][10][11][12] It is well known that hypoxia stimulates endothelial cells to release adenosine triphosphate (ATP). Purinergic P2 nucleotide receptors on endothelial cells bind this ATP, triggering secretion of nitric oxide and consequent vasodilation. The P2 class of nucleotide receptors includes the P2X receptor, which is a ligand-gated receptor channel, and the G protein-coupled P2Y receptor. 13,14 Recently, the P2X4 receptor (P2X4R) has been reported to control vascular tone and vessel remodeling in at least some blood vessels. 15-19 Interestingly, P2X4R is an important subunit of the native cardiac myocyte P2X receptor, 17 and cardiac-restricted overexpression of P2X4R can induce an enhanced contractile state of the intact heart. 20 More recently, it was found that cardiac overexpression of P2X4R increased cardiac contractility and survival in a model of myocardial infarction-induced cardiac failure. 21 It has therefore emerged as a key factor in the enhancement of cardiac performance. However, no reports have been published of alterations in P2X4R expression in certain organs, especially the heart, upon exposure to hypobaric hypoxia, and little is known about any changes in P2X4R expression in hypoxia-induced pulmonary hypertension (in which only RV is exposed to pressure overload).Even if changes in P2X4R expression occur during exposure to hypobaric hypoxia and show an apparent relation to the pulmonary pressure overload, it needs to be firmly established: (1) whether the changes in P2X4R (at both the protein and mRNA levels) occurring in certain organs, especially the heart, are coupled to the elevation in pulmonary arterial pressure seen after exposure to hypobaric hypoxia; (2) whether the changes in P2X4R protein occurring in certain organs as an adaptation to hypobaric hypoxic exposure are mirrored by similar changes at the mRNA level; and (3) whether the dis- Expression of P2X4R mRNA and Protein in RatsWith Hypobaric Hypoxia-Induced Pulmonary HypertensionYuichiro Ohata, MD; Sho Ogata, MD; Kuniaki Nakanishi, MD; Fumiko Kanazawa; Maki Uenoyama; Sadayuki Hiroi, PhD; Susumu Tominaga; Toshiaki Kawai, MD Background: The experimental pulmonary hypertension that develops in hypobaric hypoxia is characterized by structural remodeling of the heart. The P2X4 receptor (P2X4R) controls vascular tone and vessel remodeling in several blood vessels, and it has emerged as a key factor in the enhancement of cardiovascular performance.

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A novel contractile phenotype with cardiac transgenic expression of the human P2X ₄ receptor

Cited by 45 publications

References 26 publications

P2X4 Receptor Is a Glycosylated Cardiac Receptor Mediating a Positive Inotropic Response to ATP

P2X4 Receptor Is a Glycosylated Cardiac Receptor Mediating a Positive Inotropic Response to ATP

A beneficial role of cardiac P2X₄ receptors in heart failure: rescue of the calsequestrin overexpression model of cardiomyopathy

Expression of P2X4R mRNA and Protein in Rats With Hypobaric Hypoxia-Induced Pulmonary Hypertension

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A novel contractile phenotype with cardiac transgenic expression of the human P2X 4 receptor

Cited by 45 publications

References 26 publications

P2X4 Receptor Is a Glycosylated Cardiac Receptor Mediating a Positive Inotropic Response to ATP

P2X4 Receptor Is a Glycosylated Cardiac Receptor Mediating a Positive Inotropic Response to ATP

A beneficial role of cardiac P2X4 receptors in heart failure: rescue of the calsequestrin overexpression model of cardiomyopathy

Expression of P2X4R mRNA and Protein in Rats With Hypobaric Hypoxia-Induced Pulmonary Hypertension

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A novel contractile phenotype with cardiac transgenic expression of the human P2X ₄ receptor

A beneficial role of cardiac P2X₄ receptors in heart failure: rescue of the calsequestrin overexpression model of cardiomyopathy