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Su X, Dohle W, Mills SJ, Watt JM, Rossi AM, Taylor CW, Potter BVL. Inositol Adenophostin: Convergent Synthesis of a Potent Agonist of d- myo-Inositol 1,4,5-Trisphosphate Receptors. ACS OMEGA 2020; 5:28793-28811. [PMID: 33195933 PMCID: PMC7659177 DOI: 10.1021/acsomega.0c04145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
d-myo-Inositol 1,4,5-trisphosphate receptors (IP3Rs) are Ca2+ channels activated by the intracellular messenger inositol 1,4,5-trisphosphate (IP3, 1). The glyconucleotide adenophostin A (AdA, 2) is a potent agonist of IP3Rs. A recent synthesis of d-chiro-inositol adenophostin (InsAdA, 5) employed suitably protected chiral building blocks and replaced the d-glucose core by d-chiro-inositol. An alternative approach to fully chiral material is now reported using intrinsic sugar chirality to avoid early isomer resolution, involving the coupling of a protected and activated racemic myo-inositol derivative to a d-ribose derivative. Diastereoisomer separation was achieved after trans-isopropylidene group removal and the absolute ribose-inositol conjugate stereochemistry assigned with reference to the earlier synthesis. Optimization of stannylene-mediated regiospecific benzylation was explored using the model 1,2-O-isopropylidene-3,6-di-O-benzyl-myo-inositol and conditions successfully transferred to one conjugate diastereoisomer with 3:1 selectivity. However, only roughly 1:1 regiospecificity was achieved on the required diastereoisomer. The conjugate regioisomers of benzyl derivatives 39 and 40 were successfully separated and 39 was transformed subsequently to InsAdA after amination, pan-phosphorylation, and deprotection. InsAdA from this synthetic route bound with greater affinity than AdA to IP3R1 and was more potent in releasing Ca2+ from intracellular stores through IP3Rs. It is the most potent full agonist of IP3R1 known and .equipotent with material from the fully chiral synthetic route.
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Affiliation(s)
- Xiangdong Su
- Medicinal
Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, U.K.
| | - Wolfgang Dohle
- Medicinal
Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, U.K.
| | - Stephen J. Mills
- Medicinal
Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, U.K.
| | - Joanna M. Watt
- Medicinal
Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, U.K.
- Wolfson
Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, U.K.
| | - Ana M. Rossi
- Department
of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K.
| | - Colin W. Taylor
- Department
of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U.K.
| | - Barry V. L. Potter
- Medicinal
Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, U.K.
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Shipton ML, Riley AM, Rossi AM, Brearley CA, Taylor CW, Potter BVL. Both d- and l-Glucose Polyphosphates Mimic d- myo-Inositol 1,4,5-Trisphosphate: New Synthetic Agonists and Partial Agonists at the Ins(1,4,5)P 3 Receptor. J Med Chem 2020; 63:5442-5457. [PMID: 32286062 PMCID: PMC7260056 DOI: 10.1021/acs.jmedchem.0c00215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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Chiral sugar derivatives are potential
cyclitol surrogates of the
Ca2+-mobilizing intracellular messenger d-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]. Six novel polyphosphorylated analogues derived from both d- and l-glucose were synthesized. Binding to Ins(1,4,5)P3 receptors [Ins(1,4,5)P3R] and the ability to release
Ca2+ from intracellular stores via type 1 Ins(1,4,5)P3Rs were investigated. β-d-Glucopyranosyl 1,3,4-tris-phosphate,
with similar phosphate regiochemistry and stereochemistry to Ins(1,4,5)P3, and α-d-glucopyranosyl 1,3,4-tris-phosphate
are full agonists, being equipotent and 23-fold less potent than Ins(1,4,5)P3, respectively, in Ca2+-release assays and similar
to Ins(1,4,5)P3 and 15-fold weaker in binding assays. They
can be viewed as truncated analogues of adenophostin A and refine
understanding of structure-activity relationships for this Ins(1,4,5)P3R agonist. l-Glucose-derived ligands, methyl α-l-glucopyranoside 2,3,6-trisphosphate and methyl α-l-glucopyranoside 2,4,6-trisphosphate, are also active, while
their corresponding d-enantiomers, methyl α-d-glucopyranoside 2,3,6-trisphosphate and methyl α-d-glucopyranoside 2,4,6-trisphosphate, are inactive. Interestingly,
both l-glucose-derived ligands are partial agonists: they
are among the least efficacious agonists of Ins(1,4,5)P3R yet identified, providing new leads for antagonist development.
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Affiliation(s)
- Megan L Shipton
- Drug Discovery & Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, U. K
| | - Andrew M Riley
- Drug Discovery & Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, U. K
| | - Ana M Rossi
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U. K
| | - Charles A Brearley
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U. K
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, U. K
| | - Barry V L Potter
- Drug Discovery & Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, U. K
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Mills SJ, Rossi AM, Konieczny V, Bakowski D, Taylor CW, Potter BVL. d- chiro-Inositol Ribophostin: A Highly Potent Agonist of d- myo-Inositol 1,4,5-Trisphosphate Receptors: Synthesis and Biological Activities. J Med Chem 2020; 63:3238-3251. [PMID: 32052631 PMCID: PMC7104261 DOI: 10.1021/acs.jmedchem.9b01986] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Analogues
of the Ca2+-releasing intracellular messenger d-myo-inositol 1,4,5-trisphosphate [1, Ins(1,4,5)P3] are important synthetic targets. Replacement
of the α-glucopyranosyl motif in the natural product mimic adenophostin 2 by d-chiro-inositol in d-chiro-inositol adenophostin 4 increased
the potency. Similar modification of the non-nucleotide Ins(1,4,5)P3 mimic ribophostin 6 may increase the activity. d-chiro-Inositol ribophostin 10 was synthesized by coupling as building blocks suitably protected
ribose 12 with l-(+)-3-O-trifluoromethylsulfonyl-6-O-p-methoxybenzyl-1,2:4,5-di-O-isopropylidene-myo-inositol 11. Separable
diastereoisomeric 3-O-camphanate esters of (±)-6-O-p-methoxy-benzyl-1,2:4,5-di-O-isopropylidene-myo-inositol allowed the preparation
of 11. Selective trans-isopropylidene
deprotection in coupled 13, then monobenzylation gave
separable regioisomers 15 and 16. p-Methoxybenzyl group deprotection of 16, phosphitylation/oxidation,
then deprotection afforded 10, which was a full agonist
in Ca2+-release assays; its potency and binding affinity
for Ins(1,4,5)P3R were similar to those of adenophostin.
Both 4 and 10 elicited a store-operated
Ca2+ current ICRAC in patch-clamped cells, unlike
Ins(1,4,5)P3 consistent with resistance to metabolism. d-chiro-Inositol ribophostin is the most potent
small-molecule Ins(1,4,5)P3 receptor agonist without a
nucleobase yet synthesized.
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Affiliation(s)
- Stephen J Mills
- Drug Discovery & Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Ana M Rossi
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Vera Konieczny
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Daniel Bakowski
- Centre of Integrative Physiology, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom
| | - Barry V L Potter
- Drug Discovery & Medicinal Chemistry, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
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4
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Synthesis and in vitro anticancer activity evaluation of novel bioreversible phosphate inositol derivatives. Eur J Med Chem 2015; 93:172-81. [DOI: 10.1016/j.ejmech.2015.01.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 12/29/2014] [Accepted: 01/31/2015] [Indexed: 01/13/2023]
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5
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A fluorescence-based method for evaluating inositol 1,4,5-trisphosphate receptor ligands: Determination of subtype selectivity and partial agonist effects. J Biotechnol 2013; 167:248-54. [DOI: 10.1016/j.jbiotec.2013.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 05/19/2013] [Accepted: 06/23/2013] [Indexed: 11/22/2022]
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Sureshan KM, Riley AM, Thomas MP, Tovey SC, Taylor CW, Potter BVL. Contribution of phosphates and adenine to the potency of adenophostins at the IP₃ receptor: synthesis of all possible bisphosphates of adenophostin A. J Med Chem 2012; 55:1706-20. [PMID: 22248345 PMCID: PMC3285137 DOI: 10.1021/jm201571p] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Although adenophostin A (AdA), the most potent agonist
of d-myo-inositol 1,4,5-trisphosphate receptors
(IP3R), is thought to mimic IP3, the relative
roles
of the different phosphate groups and the adenosine motif have not
been established. We synthesized all three possible bisphosphate analogues
of AdA and glucose 3,4-bisphosphate (7, AdA lacking the
2′-AMP). 2′-Dephospho-AdA (6) was prepared
via a novel regioselective dephosphorylation strategy. Assessment
of the abilities of these bisphosphates to stimulate intracellular
Ca2+ release using recombinant rat type 1 IP3R (IP3R1) revealed that 6, a mimic of Ins(4,5)P2, is only 4-fold less potent than IP3, while 7 is some 400-fold weaker and even 3″-dephospho-AdA
(5) is measurably active, despite missing one of the
vicinal bisphosphate groups normally thought to be crucial for IP3-like activity. Compound 6 is the most potent
bisphosphate yet discovered with activity at IP3R. Thus,
adenosine has a direct role independent of the 2′-phosphate
group in contributing toward the potency of adenophostins, the vicinal
bisphosphate motif is not essential for activity at the IP3R, as always thought, and it is possible to design potent agonists
with just two of the three phosphates. A model with a possible adenine–R504
interaction supports the activity of 5 and 6 and also allows a reappraisal of the unexpected activity previously
reported for the AdA regioisomer 2″-phospho-3″-dephospho-AdA 40.
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Affiliation(s)
- Kana M Sureshan
- Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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7
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Rossi AM, Riley AM, Potter BV, Taylor CW. Adenophostins. CURRENT TOPICS IN MEMBRANES 2010; 66:209-33. [DOI: 10.1016/s1063-5823(10)66010-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
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8
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Benito D, Isabel Matheu M, Morère A, Díaz Y, Castillón S. Designing an effective approach for obtaining methylenecarboxylate analogues of adenophostin A. Preliminary results. Carbohydr Res 2009; 344:2559-67. [DOI: 10.1016/j.carres.2009.09.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 09/16/2009] [Accepted: 09/27/2009] [Indexed: 11/29/2022]
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9
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Abstract
The inositol 1,4,5-trisphosphate (InsP3) receptors (InsP3Rs) are a family of Ca2+ release channels localized predominately in the endoplasmic reticulum of all cell types. They function to release Ca2+ into the cytoplasm in response to InsP3 produced by diverse stimuli, generating complex local and global Ca2+ signals that regulate numerous cell physiological processes ranging from gene transcription to secretion to learning and memory. The InsP3R is a calcium-selective cation channel whose gating is regulated not only by InsP3, but by other ligands as well, in particular cytoplasmic Ca2+. Over the last decade, detailed quantitative studies of InsP3R channel function and its regulation by ligands and interacting proteins have provided new insights into a remarkable richness of channel regulation and of the structural aspects that underlie signal transduction and permeation. Here, we focus on these developments and review and synthesize the literature regarding the structure and single-channel properties of the InsP3R.
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Affiliation(s)
- J Kevin Foskett
- Department of Physiology, University of Pennsylvania, Philadelphia 19104-6085, USA.
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10
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Chrétien F, Roussel F, Hilly M, Mauger J, Chapleur Y. New Sugar‐Based Permeant Analogs of D‐ Myo ‐Inositol 1,4,5‐Trisphosphate Mimicking the Effect of Vasopressin: Synthesis and Biologic Evaluation*. J Carbohydr Chem 2005. [DOI: 10.1081/car-200068070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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11
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Laporte R, Hui A, Laher I. Pharmacological modulation of sarcoplasmic reticulum function in smooth muscle. Pharmacol Rev 2005; 56:439-513. [PMID: 15602008 DOI: 10.1124/pr.56.4.1] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The sarco/endoplasmic reticulum (SR/ER) is the primary storage and release site of intracellular calcium (Ca2+) in many excitable cells. The SR is a tubular network, which in smooth muscle (SM) cells distributes close to cellular periphery (superficial SR) and in deeper aspects of the cell (deep SR). Recent attention has focused on the regulation of cell function by the superficial SR, which can act as a buffer and also as a regulator of membrane channels and transporters. Ca2+ is released from the SR via two types of ionic channels [ryanodine- and inositol 1,4,5-trisphosphate-gated], whereas accumulation from thecytoplasm occurs exclusively by an energy-dependent sarco-endoplasmic reticulum Ca2+-ATPase pump (SERCA). Within the SR, Ca2+ is bound to various storage proteins. Emerging evidence also suggests that the perinuclear portion of the SR may play an important role in nuclear transcription. In this review, we detail the pharmacology of agents that alter the functions of Ca2+ release channels and of SERCA. We describe their use and selectivity and indicate the concentrations used in investigating various SM preparations. Important aspects of cell regulation and excitation-contractile activity coupling in SM have been uncovered through the use of such activators and inhibitors of processes that determine SR function. Likewise, they were instrumental in the recent finding of an interaction of the SR with other cellular organelles such as mitochondria. Thus, an appreciation of the pharmacology and selectivity of agents that interfere with SR function in SM has greatly assisted in unveiling the multifaceted nature of the SR.
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Affiliation(s)
- Régent Laporte
- Ferring Research Institute, Inc., Ferring Pharmaceuticals, San Diego, California, USA
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12
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Terauchi M, Yahiro Y, Abe H, Ichikawa S, Tovey SC, Dedos SG, Taylor CW, Potter BV, Matsuda A, Shuto S. Synthesis of 4,8-anhydro-d-glycero-d-ido-nonanitol 1,6,7-trisphosphate as a novel IP3 receptor ligand using a stereoselective radical cyclization reaction based on a conformational restriction strategy. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.02.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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13
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Morris SA, Nerou EP, Riley AM, Potter BVL, Taylor CW. Determinants of adenophostin A binding to inositol trisphosphate receptors. Biochem J 2002; 367:113-20. [PMID: 12088506 PMCID: PMC1222864 DOI: 10.1042/bj20020675] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2002] [Revised: 06/25/2002] [Accepted: 06/27/2002] [Indexed: 11/17/2022]
Abstract
Inositol 1,4,5-trisphosphate (IP(3)) receptors from cerebellum and recombinant type 1 IP(3) receptors expressed in Sf9 cells had indistinguishable affinities for IP(3) ( K (d)=6.40+/-0.48 nM) and adenophostin A ( K (d)=0.89+/-0.05 nM). In cytosol-like medium, each of the three mammalian IP(3) receptor subtypes when expressed in Sf9 cells bound adenophostin A with greater affinity than IP(3). It has been suggested that adenophostin A binds with high affinity only in the presence of ATP, but we found that adenophostin A similarly displaced [(3)H]IP(3) from type 1 IP(3) receptors whatever the ATP concentration. N-terminal fragments of the type 1 receptor were expressed with and without the S1 splice site; its removal had no effect on [(3)H]IP(3) binding to the 1-604 protein, but abolished binding to the 224-604 protein. The 1-604 fragment and full-length receptor bound adenophostin A with the same affinity, but the fragment had 3-fold greater affinity for IP(3), suggesting that C-terminal residues selectively inhibit IP(3) binding. The 224-604S1(+) fragment bound IP(3) and adenophostin A with increased affinity, but as with the 1-604 fragment it bound adenophostin A with only 2-fold greater affinity than IP(3). High-affinity binding of adenophostin A may be partially determined by its 2'-phosphate interacting more effectively than the 1-phosphate of IP(3) with residues within the IP(3)-binding core. This may account for the 2-fold greater affinity of adenophostin A relative to IP(3) for the minimal IP(3)-binding domain. In addition we suggest that C-terminal residues, which impede access of IP(3), may selectively interact with adenophostin A to allow it unhindered access to the IP(3)-binding domain.
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Affiliation(s)
- Stephen A Morris
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, U.K
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14
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Roussel F, Moitessier N, Hilly M, Chrétien F, Mauger JP, Chapleur Y. D-myo-inositol-1,4,5-trisphosphate and adenophostin mimics: importance of the spatial orientation of a phosphate group on the biological activity. Bioorg Med Chem 2002; 10:759-68. [PMID: 11814866 DOI: 10.1016/s0968-0896(01)00329-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Three different routes for the synthesis of heterocyclic analogues of the second messenger D-myo-inositol-1,4,5-trisphosphate (InsP(3)) and the natural adenophostins, starting from allyl D-xyloside are described. The two diastereoisomers at C-2 of new compounds, which we named xylophostins, were obtained. The preliminary biological studies shows that the presence of the adenine residue has a beneficial effect on the affinity for the receptor. The low potency of one of the two diastereoisomeric compounds shows that the configuration of the carbon bearing the non-vicinal phosphate group is an important requirement for a high affinity to the receptor. These results provide evidence for the existence of a binding pocket for the adenine ring nearby the InsP(3) binding site. The consequence of these stabilizing interactions should be to place the phosphate group in a suitable position to perfectly mimic InsP(3) in the more active diastereoisomer. Obviously, in the other diastereoisomer, the phosphate cannot accommodate the same orientation, thus explaining the low affinity. The existence of such a binding pocket for adenine is in line with the high potency of adenophostins.
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MESH Headings
- Adenosine/analogs & derivatives
- Adenosine/chemical synthesis
- Adenosine/chemistry
- Adenosine/pharmacology
- Animals
- Binding Sites
- Binding, Competitive
- Calcium Channel Agonists/chemical synthesis
- Calcium Channel Agonists/chemistry
- Calcium Channel Agonists/pharmacology
- Calcium Channels/chemistry
- Calcium Channels/metabolism
- Hepatocytes/metabolism
- Inositol 1,4,5-Trisphosphate/chemical synthesis
- Inositol 1,4,5-Trisphosphate/chemistry
- Inositol 1,4,5-Trisphosphate/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors
- Microsomes
- Molecular Conformation
- Molecular Mimicry
- Phosphates/chemistry
- Rats
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, Cytoplasmic and Nuclear/chemistry
- Receptors, Cytoplasmic and Nuclear/metabolism
- Second Messenger Systems/drug effects
- Structure-Activity Relationship
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Affiliation(s)
- Fabien Roussel
- Groupe SUCRES, UMR 7565, CNRS-Université Henri Poincaré Nancy 1, BP 239, F-54506 Vandoeuvre, France
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15
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Abstract
The adenophostins exhibit approximately 10-100 times higher receptor binding and Ca2+ mobilising potencies in comparison with the natural second messenger D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P3]. Despite many synthetic attempts to determine the minimal structural requirement for this unusual behaviour of the adenophostins, few related simplified analogues displaying higher activity than that of Ins(1,4,5)P3 have been reported. However, biological evaluation of such analogues has revealed that one of the key factors for the enhanced biological activity is the adenine moiety. To further understand the effect that the adenine base has upon the activity of the adenophostins, congeners in which this functionality is replaced by uracil, benzimidazole, 2-methoxynaphthalene, 4-methylanisole and 4-methylnaphthalene using the common intermediate 1,2-di-O-acetyl-5-O-benzyl-3-O-(3,4-di-O-acetyl-2,6-di-O-benzyl-alpha-D-glucopyranosyl)-ribofuranose have been synthesised using a base replacement strategy. The synthesis of the uracil and benzimidazole analogues was achieved using the Vorbrüggen condensation procedure. The 1'-C-glycosidic analogues were prepared using Friedel-Crafts type C-aryl glycosidation reactions. Phosphate groups were introduced using the phosphoramidite method with subsequent removal of all-benzyl protecting groups by catalytic hydrogenation or catalytic hydrogen transfer. Apart from one analogue with an alpha-glycosidic linkage all compounds were more potent than Ins(1,4,5)P3 and most tended more towards adenophostin in activity. These analogues will be valuable tools to unravel the role that the adenine moiety plays in the potent activity of the adenophostins and demonstrate that this strategy is effective at producing highly potent ligands.
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Affiliation(s)
- S Shuto
- Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, UK
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16
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Correa V, Riley AM, Shuto S, Horne G, Nerou EP, Marwood RD, Potter BV, Taylor CW. Structural determinants of adenophostin A activity at inositol trisphosphate receptors. Mol Pharmacol 2001; 59:1206-15. [PMID: 11306705 DOI: 10.1124/mol.59.5.1206] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Adenophostin A is the most potent known agonist of inositol 1,4,5-trisphosphate (InsP(3)) receptors. Ca(2+) release from permeabilized hepatocytes was 9.9 +/- 1.6-fold more sensitive to adenophostin A (EC(50), 14.7 +/- 2.4 nM) than to InsP(3) (145 +/- 10 nM), consistent with the greater affinity of adenophostin A for hepatic InsP(3) receptors (K(d) = 0.48 +/- 0.06 and 3.09 +/- 0.33 nM, respectively). Here, we systematically modify the structures of the glucose, ribose, and adenine moieties of adenophostin A and use Ca(2+) release and binding assays to define their contributions to high-affinity binding. Progressive trimming of the adenine of adenophostin A reduced potency, but it fell below that of InsP(3) only after complete removal of the adenine. Even after substantial modifications of the adenine (to uracil or even unrelated aromatic rings, retaining the beta-orientation), the analogs were more potent than InsP(3). The only analog with an alpha-ribosyl linkage had massively decreased potency. The 2'-phosphate on the ribose ring of adenophostin A was essential and optimally active when present on a five-membered ring in a position stereochemically equivalent to its location in adenophostin A. Xylo-adenophostin, where xylose replaces the glucose ring of adenophostin A, was only slightly less potent than adenophostin A, whereas manno-adenophostin (mannose replacing glucose) had similar potency to InsP(3). These results are consistent with the relatively minor role of the 3-hydroxyl of InsP(3) (the equivalent is absent from xylo-adenophostin) and greater role of the equatorial 6-hydroxyl (the equivalent is axial in manno-adenophostin). This is the first comprehensive analysis of all the key structural elements of adenophostin A, and it provides a working model for the design of related high-affinity ligands of InsP(3) receptors.
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Affiliation(s)
- V Correa
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1QJ, United Kingdom
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Shuto S, Fukuoka M, Abe H, Matsuda A. Intracellular Ca(2+)-mobilizing adenine nucleotides. Synthesis and biological activity of cyclic ADP-carbocyclic-ribose and C-glycosidic analog of adenophostin A. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2001; 20:461-70. [PMID: 11563061 DOI: 10.1081/ncn-100002320] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We designed novel Ca(2+)-mobilizing purine nucleotides, cyclic ADP-carbocyclicribose 4, and its inosine congener 5, and C-glycosidic adenophostin A 6. In the synthesis of cADPR analogs, the intramolecular condensation to form the pyrophosphate linkage should be the key step. We developed an efficient method for forming such an intramolecular pyrophosphate linkage by the activation of the phenylthiophosphate group with I2 or AgNO3. Using this method, we achieved to synthesize the target compounds 4 and 5. The synthesis of C-glycosidic analog 6 of adenophostin A was achieved using a temporary silicon-tethered radical coupling reaction for constructing (3'alpha, 1" alpha)-C-glycosidic structure as the key step.
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Affiliation(s)
- S Shuto
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
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Mak DOD, McBride S, Foskett JK. ATP-dependent adenophostin activation of inositol 1,4,5-trisphosphate receptor channel gating: kinetic implications for the durations of calcium puffs in cells. J Gen Physiol 2001; 117:299-314. [PMID: 11279251 PMCID: PMC2217258 DOI: 10.1085/jgp.117.4.299] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2000] [Accepted: 02/13/2001] [Indexed: 11/26/2022] Open
Abstract
The inositol 1,4,5-trisphosphate (InsP(3)) receptor (InsP(3)R) is a ligand-gated intracellular Ca(2+) release channel that plays a central role in modulating cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)). The fungal metabolite adenophostin A (AdA) is a potent agonist of the InsP(3)R that is structurally different from InsP(3) and elicits distinct calcium signals in cells. We have investigated the effects of AdA and its analogues on single-channel activities of the InsP(3)R in the outer membrane of isolated Xenopus laevis oocyte nuclei. InsP(3)R activated by either AdA or InsP(3) have identical channel conductance properties. Furthermore, AdA, like InsP(3), activates the channel by tuning Ca(2+) inhibition of gating. However, gating of the AdA-liganded InsP(3)R has a critical dependence on cytoplasmic ATP free acid concentration not observed for InsP(3)-liganded channels. Channel gating activated by AdA is indistinguishable from that elicited by InsP(3) in the presence of 0.5 mM ATP, although the functional affinity of the channel is 60-fold higher for AdA. However, in the absence of ATP, gating kinetics of AdA-liganded InsP(3)R were very different. Channel open time was reduced by 50%, resulting in substantially lower maximum open probability than channels activated by AdA in the presence of ATP, or by InsP(3) in the presence or absence of ATP. Also, the higher functional affinity of InsP(3)R for AdA than for InsP(3) is nearly abolished in the absence of ATP. Low affinity AdA analogues furanophostin and ribophostin activated InsP(3)R channels with gating properties similar to those of AdA. These results provide novel insights for interpretations of observed effects of AdA on calcium signaling, including the mechanisms that determine the durations of elementary Ca(2+) release events in cells. Comparisons of single-channel gating kinetics of the InsP(3)R activated by InsP(3), AdA, and its analogues also identify molecular elements in InsP(3)R ligands that contribute to binding and activation of channel gating.
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Affiliation(s)
- Don-On Daniel Mak
- Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Sean McBride
- Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - J. Kevin Foskett
- Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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de Kort M, Regenbogen AD, Overkleeft HS, John Challiss R, Iwata Y, Miyamoto S, van der Marel GA, van Boom JH. Synthesis and Biological Evaluation of Cyclophostin: A 5′,6″-Tethered Analog of Adenophostin A. Tetrahedron 2000. [DOI: 10.1016/s0040-4020(00)00480-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Felemez M, Marwood RD, Potter BV, Spiess B. Inframolecular studies of the protonation of adenophostin A: comparison with 1-D-myo-inositol 1,4,5-trisphosphate. Biochem Biophys Res Commun 1999; 266:334-40. [PMID: 10600504 DOI: 10.1006/bbrc.1999.1832] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenophostin A is a glyconucleotide natural product with the highest known potency for the D-myo-inositol 1,4,5-trisphosphate receptor. Using synthetic adenophostin A we have investigated the macroscopic and microscopic protonation process of this compound by performing (31)P NMR, (1)H NMR, and potentiometric titration experiments. The logarithms of the first to the fourth stepwise protonation constants are, respectively, log K(1) = 8.48, log K(2) = 6.20, log K(3) = 4.96, and log K(4) = 3.80. The latter constant refers to the protonation equilibrium involving the N1 adenine nitrogen. From the microconstants the protonation fractions of each individual phosphate group can be calculated. Remarkably, the ionization state of the phosphates of adenophostin A at near physiological pH is very similar to those of inositol 1,4,5-trisphosphate, indicating that differences in phosphate charge cannot account for the high potency of this molecule. The analysis of the (1)H chemical shifts vs pH provided complementary conformational information. In particular, a slight "wrongway shift" of H1" can be related to the protonation of P2, thus indicating a short H1"-P2 distance. Our results are in line with a recently published model in which, however, a certain degree of constraint would keep the ribose 2'-phosphate moiety close to the glucose ring phosphates.
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Affiliation(s)
- M Felemez
- Laboratoire de Pharmacochimie Moléculaire, UMR 7081 du CNRS, Faculté de Pharmacie, 74, route du Rhin, Illkirch Cedex, 67401, France
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