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Barresi E, Martini C, Da Settimo F, Greco G, Taliani S, Giacomelli C, Trincavelli ML. Allosterism vs. Orthosterism: Recent Findings and Future Perspectives on A 2B AR Physio-Pathological Implications. Front Pharmacol 2021; 12:652121. [PMID: 33841166 PMCID: PMC8024542 DOI: 10.3389/fphar.2021.652121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/12/2021] [Indexed: 11/13/2022] Open
Abstract
The development of GPCR (G-coupled protein receptor) allosteric modulators has attracted increasing interest in the last decades. The use of allosteric modulators in therapy offers several advantages with respect to orthosteric ones, as they can fine-tune the tissue responses to the endogenous agonist. Since the discovery of the first A1 adenosine receptor (AR) allosteric modulator in 1990, several efforts have been made to develop more potent molecules as well as allosteric modulators for all adenosine receptor subtypes. There are four subtypes of AR: A1, A2A, A2B, and A3. Positive allosteric modulators of the A1 AR have been proposed for the cure of pain. A3 positive allosteric modulators are thought to be beneficial during inflammatory processes. More recently, A2A and A2B AR allosteric modulators have also been disclosed. The A2B AR displays the lowest affinity for its endogenous ligand adenosine and is mainly activated as a consequence of tissue damage. The A2B AR activation has been found to play a crucial role in chronic obstructive pulmonary disease, in the protection of the heart from ischemic injury, and in the process of bone formation. In this context, allosteric modulators of the A2B AR may represent pharmacological tools useful to develop new therapeutic agents. Herein, we provide an up-to-date highlight of the recent findings and future perspectives in the field of orthosteric and allosteric A2B AR ligands. Furthermore, we compare the use of orthosteric ligands with positive and negative allosteric modulators for the management of different pathological conditions.
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Affiliation(s)
| | | | | | - Giovanni Greco
- Department of Pharmacy, University of Naples "Federico II", Naples, Italy
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2
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Taliani S, Da Settimo F, Martini C, Laneri S, Novellino E, Greco G. Exploiting the Indole Scaffold to Design Compounds Binding to Different Pharmacological Targets. Molecules 2020; 25:molecules25102331. [PMID: 32429433 PMCID: PMC7287756 DOI: 10.3390/molecules25102331] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 12/14/2022] Open
Abstract
Several indole derivatives have been disclosed by our research groups that have been collaborating for nearly 25 years. The results of our investigations led to a variety of molecules binding selectively to different pharmacological targets, specifically the type A γ-aminobutyric acid (GABAA) chloride channel, the translocator protein (TSPO), the murine double minute 2 (MDM2) protein, the A2B adenosine receptor (A2B AR) and the Kelch-like ECH-associated protein 1 (Keap1). Herein, we describe how these works were conceived and carried out thanks to the versatility of indole nucleus to be exploited in the design and synthesis of drug-like molecules.
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Affiliation(s)
- Sabrina Taliani
- Department of Pharmacy, University of Pisa, Via Bonanno Pisano, 6, 56126 Pisa, Italy; (F.D.S.); (C.M.)
- Correspondence: (S.T.); (G.G.); Tel.: +39-050-2219547 (S.T.); +39-081-678645 (G.G.)
| | - Federico Da Settimo
- Department of Pharmacy, University of Pisa, Via Bonanno Pisano, 6, 56126 Pisa, Italy; (F.D.S.); (C.M.)
| | - Claudia Martini
- Department of Pharmacy, University of Pisa, Via Bonanno Pisano, 6, 56126 Pisa, Italy; (F.D.S.); (C.M.)
| | - Sonia Laneri
- Department of Pharmacy, University of Naples “Federico II”, Via D. Montesano, 49, 80131 Naples, Italy; (S.L.); (E.N.)
| | - Ettore Novellino
- Department of Pharmacy, University of Naples “Federico II”, Via D. Montesano, 49, 80131 Naples, Italy; (S.L.); (E.N.)
| | - Giovanni Greco
- Department of Pharmacy, University of Naples “Federico II”, Via D. Montesano, 49, 80131 Naples, Italy; (S.L.); (E.N.)
- Correspondence: (S.T.); (G.G.); Tel.: +39-050-2219547 (S.T.); +39-081-678645 (G.G.)
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Vega Alanis BA, Iorio MT, Silva LL, Bampali K, Ernst M, Schnürch M, Mihovilovic MD. Allosteric GABA A Receptor Modulators-A Review on the Most Recent Heterocyclic Chemotypes and Their Synthetic Accessibility. Molecules 2020; 25:E999. [PMID: 32102309 PMCID: PMC7070463 DOI: 10.3390/molecules25040999] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 11/17/2022] Open
Abstract
GABAA receptor modulators are structurally almost as diverse as their target protein. A plethora of heterocyclic scaffolds has been described as modulating this extremely important receptor family. Some made it into clinical trials and, even on the market, some were dismissed. This review focuses on the synthetic accessibility and potential for library synthesis of GABAA receptor modulators containing at least one heterocyclic scaffold, which were disclosed within the last 10 years.
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Affiliation(s)
- Blanca Angelica Vega Alanis
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/193, 1060 Vienna, Austria; (B.A.V.A.); (M.T.I.); (M.D.M.)
| | - Maria Teresa Iorio
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/193, 1060 Vienna, Austria; (B.A.V.A.); (M.T.I.); (M.D.M.)
| | - Luca L. Silva
- Department of Anesthesiology and Intensive Care Medicine, Charité–Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany;
| | - Konstantina Bampali
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria;
| | - Margot Ernst
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria;
| | - Michael Schnürch
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/193, 1060 Vienna, Austria; (B.A.V.A.); (M.T.I.); (M.D.M.)
| | - Marko D. Mihovilovic
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/193, 1060 Vienna, Austria; (B.A.V.A.); (M.T.I.); (M.D.M.)
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El-Helby AGA, Ayyad RR, Sakr HM, Abdelrahim AS, El-Adl K, Sherbiny FS, Eissa IH, Khalifa MM. Design, synthesis, molecular modeling and biological evaluation of novel 2,3-dihydrophthalazine-1,4-dione derivatives as potential anticonvulsant agents. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2016.10.052] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Taliani S, Trincavelli ML, Cosimelli B, Laneri S, Severi E, Barresi E, Pugliesi I, Daniele S, Giacomelli C, Greco G, Novellino E, Martini C, Da Settimo F. Modulation of A2B adenosine receptor by 1-Benzyl-3-ketoindole derivatives. Eur J Med Chem 2013; 69:331-7. [PMID: 24077183 DOI: 10.1016/j.ejmech.2013.09.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 09/02/2013] [Indexed: 11/17/2022]
Abstract
We have disclosed a series of 1-benzyl-3-ketoindole derivatives acting as either positive or negative modulators of the human A(2B) adenosine receptor (A(2B) AR) depending on small differences in their side chain. The new compounds were designed taking into account structural similarities between AR antagonists and ligands of the GABA(A)/benzodiazepine receptor. All compounds resulted totally inactive at A(2A) and A₃ ARs and showed small (8a,b) or none (7a,b, 8c and 9a,b) affinity for A₁ AR. When tested on A(2B) AR-transfected CHO cells, 7a,b and 8a acted as positive modulators, whereas 8b,c and 9a,b acted as negative modulators, enhancing or weakening the NECA-induced increase of cAMP levels, respectively. Compounds 7-9 might be regarded as useful biological and pharmacological tools to explore the therapeutic potential of A(2B) AR modulators, while their 3-ketoindole scaffold might be taken as a reference to design new analogs.
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Affiliation(s)
- Sabrina Taliani
- Dipartimento di Farmacia, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
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Schmidt S, Preu L, Lemcke T, Totzke F, Schächtele C, Kubbutat MH, Kunick C. Dual IGF-1R/SRC inhibitors based on a N′-aroyl-2-(1H-indol-3-yl)-2-oxoacetohydrazide structure. Eur J Med Chem 2011; 46:2759-69. [DOI: 10.1016/j.ejmech.2011.03.065] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 03/29/2011] [Accepted: 03/30/2011] [Indexed: 01/07/2023]
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Taliani S, Cosimelli B, Da Settimo F, Marini AM, La Motta C, Simorini F, Salerno S, Novellino E, Greco G, Cosconati S, Marinelli L, Salvetti F, L'Abbate G, Trasciatti S, Montali M, Costa B, Martini C. Identification of anxiolytic/nonsedative agents among indol-3-ylglyoxylamides acting as functionally selective agonists at the gamma-aminobutyric acid-A (GABAA) alpha2 benzodiazepine receptor. J Med Chem 2009; 52:3723-34. [PMID: 19469479 DOI: 10.1021/jm9001154] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Anxioselective agents may be identified among compounds binding selectively to the alpha(2)beta(x)gamma(2) subtype of the gamma-aminobutyric acid-A (GABA(A))/central benzodiazepine receptor (BzR) complex and behaving as agonists or among compounds binding with comparable potency to various BzR subtypes but eliciting agonism only at the alpha(2)beta(x)gamma(2) receptor. Because of subtle steric differences among BzR subtypes, the latter approach has proved much more successful. A biological screening within the class of indol-3-ylglyoxylamides 1-3 allowed us to identify compounds 1c and 2b as potential anxiolytic/nonsedative agents showing alpha(2) selective efficacy in vitro and anxioselective effects in vivo. According to molecular modeling studies, and consistently with SARs accumulated in the past decade, 5-NO(2)- and 5-H-indole derivatives would preferentially bind to BzR by placing the indole ring in the L(Di) and the L(2) receptor binding sites, respectively.
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Affiliation(s)
- Sabrina Taliani
- Dipartimento di Scienze Farmaceutiche, Universita di Pisa, Via Bonanno 6, 56126 Pisa, Italy.
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Kahnberg P, Howard MH, Liljefors T, Nielsen M, Nielsen EØ, Sterner O, Pettersson I. The use of a pharmacophore model for identification of novel ligands for the benzodiazepine binding site of the GABAA receptor. J Mol Graph Model 2005; 23:253-61. [PMID: 15530821 DOI: 10.1016/j.jmgm.2004.06.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 06/04/2004] [Accepted: 06/23/2004] [Indexed: 11/27/2022]
Abstract
A Catalyst pharmacophore model has been developed for the benzodiazepine site within the GABA(A) receptor complex. The model is based on a pharmacophore model originally proposed by Cook and co-workers (Drug Des. Discovery 1995, 12, 193-248) and further developed by Kahnberg et al. (J. Med. Chem. 2002, 45, 4188-4201). The Catalyst pharmacophore model has been validated by using a series of flavonoids with varying affinities for the benzodiazepine receptor and has then been used as a search query in database searching with the aim of finding novel structures which have the possibility to be modified into novel lead compounds. Five of the hits from the database searching were purchased and their affinities for the benzodiazepine site of the GABA(A) receptor were determined. Two of the compounds displayed K(i) values below 10 microM. The substance showing highest potency in-vitro displayed an affinity of 121 nM making it an interesting compound for optimization. The false positive compounds (K(i) values >10 microM affinities) have been analysed in terms of conformational energy penalties and possibilities for hydrogen bond interactions. The analysis clearly demonstrates the need for post processing of Catalyst hits.
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Affiliation(s)
- Pia Kahnberg
- Department of Organic and Bioorganic Chemistry, Lund University, P.O.Box 124, S-22100 Lund, Sweden
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Primofiore G, Da Settimo F, Taliani S, Salerno S, Novellino E, Greco G, Cosimelli B, Besnard F, Costa B, Montali M, Martini C. High Affinity Central Benzodiazepine Receptor Ligands: Synthesis and Biological Evaluation of a Series of Phenyltriazolobenzotriazindione Derivatives. J Med Chem 2005; 48:2936-43. [PMID: 15828832 DOI: 10.1021/jm0408722] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of 2-phenyl[1,2,3]triazolo[1,2-a][1,2,4]benzotriazin-1,5(6H)-diones (PTBTs), VII, were prepared and tested at the central benzodiazepine receptor (BzR). The skeleton of these compounds was designed by formally combining the N-C=O moieties of the known BzR ligands, triazoloquinoxalines (IV) and triazinobenzimidazoles (ATBIs) (VI). Most of the PTBTs displayed submicromolar/nanomolar potency at the BzR. The 9-chloro derivatives (45-49) were generally found to be more potent than their 9-unsubstituted counterparts (37-44). Compound 45 turned out to be the most potent of the PTBTs (K(i) 2.8 nM). A subset of compounds (37, 42, 45, 49), when tested for their affinity on recombinant rat alpha1beta2gamma2, alpha2beta2gamma2, and alpha5beta3gamma2 GABA(A)/Bz receptor subtypes, showed enhanced affinities for the alpha1beta2gamma2 isoform, with compounds 45 and 49 exhibiting the highest selectivity. Moreover, compounds 45 and 49 were found to display a full agonist efficacy profile at alpha1 and alpha2 receptor subtypes, and an antagonist efficacy at alpha5-containing receptors.
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Affiliation(s)
- Giampaolo Primofiore
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy.
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Primofiore G, Settimo FD, Taliani S, Marini AM, Novellino E, Greco G, Lavecchia A, Besnard F, Trincavelli L, Costa B, Martini C. Novel N-(arylalkyl)indol-3-ylglyoxylylamides targeted as ligands of the benzodiazepine receptor: synthesis, biological evaluation, and molecular modeling analysis of the structure-activity relationships. J Med Chem 2001; 44:2286-97. [PMID: 11428922 DOI: 10.1021/jm010827j] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of N-(arylalkyl)indol-3-ylglyoxylylamides (4-8) was synthesized as ligands of the benzodiazepine receptor (BzR) and tested for their ability to displace [(3)H]flumazenil from bovine brain membranes. The new compounds, bearing a branched (4) or a geometrically constrained benzyl/phenylethyl amide side chain (5-8), represent the continuation of our research on N-benzylindol-3-ylglyoxylylamides 1 (Da Settimo et al., 1996), N'-phenylindol-3-ylglyoxylohydrazides 2 (Da Settimo et al., 1998), and N-(indol-3-ylglyoxylyl)alanine derivatives 3 (Primofiore et al., 1989). A few indoles belonging to the previously investigated benzylamides 1 and phenylhydrazides 2 were synthesized and tested to enrich the SARs in these two series. The affinities and the GABA ratios of selected compounds for clonal mammalian alpha(1)beta(2)gamma(2), alpha(3)beta(2)gamma(2), and alpha(5)beta(3)gamma(2) BzR subtypes were also determined. It was hypothesized that the reduced flexibility of indoles 4-8 would both facilitate the mapping of the BzR binding cleft and increase the chances of conferring selectivity for the considered receptor subtypes. In the series of indoles 4, the introduction of a methyl group on the benzylic carbon with the R configuration improved affinity of the 5-substituted (5-Cl and 5-NO(2)) derivatives, whereas it was detrimental for their 5-unsubtituted (5-H) counterparts. All S enantiomers were less potent than the R ones. Replacement of the methyl with hydrophilic substituents on the benzylic carbon lowered affinity. The isoindolinylamide side chain was tolerated if the 5-position was unsubstituted (K(i) of 5a = 123 nM), otherwise affinity was abolished (5b, c). All the 2-indanylamides 6 and (S)-1-indanylamides 8 were devoid of any appreciable affinity. The 5-Cl and 5-NO(2) (R)-1-indanylamides 7b (K(i) 80 nM) and 7c (K(i) 28 nM) were the most potent among the indoles 5-8 geometrically constrained about the side chain. The 5-H (R)-1-indanylamide 7a displayed a lower affinity (K(i) 675 nM). The SARs developed from the new compounds, together with those collected from our previous studies, confirmed the hypothesis of different binding modes for 5-substituted and 5-unsubstituted indoles, suggesting that the shape of the lipophilic pocket L(1) (notation in accordance with Cook's BzR topological model) is asymmetric and highlighted the stereoelectronic and conformational properties of the amide side chain required for high potency. Several of the new indoles showed selectivity for the alpha(1)beta(2)gamma(2) subtype compared with the alpha(3)beta(2)gamma(2) and alpha(5)beta(3)gamma(2) subtypes (e.g.: 4t and 7c bind to these three BzR isoforms with K(i) values of 14 nM, 283 nM, 239 nM, and 9 nM, 1960 nM, 95 nM, respectively). The GABA ratios close to unity exhibited by all the tested compounds on each BzR subtype were predictive of an efficacy profile typical of antagonists.
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Affiliation(s)
- G Primofiore
- Dipartimento di Scienze Farmaceutiche and Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy.
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Primofiore G, Da Settimo F, Taliani S, Marini AM, La Motta C, Novellino E, Greco G, Gesi M, Trincavelli L, Martini C. 3-Aryl-[1,2,4]triazino[4,3-a]benzimidazol-4(10H)-ones: tricyclic heteroaromatic derivatives as a new class of benzodiazepine receptor ligands. J Med Chem 2000; 43:96-102. [PMID: 10633040 DOI: 10.1021/jm991131h] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A series of 3-substituted [1,2,4]triazino[4,3-c]benzimidazoles V were prepared and tested at the central benzodiazepine receptor (BzR). These compounds were designed as rigid analogues of the previously described N-benzylindolylglyoxylylamide derivatives IV. The title compounds V showed an affinity which depended directly on the presence of the N(10)-H group and an aromatic ring at position 3. Some of them elicited a 2- or 3-fold higher affinity with respect to that of the indolylglyoxylylamide derivatives IV (R = H). The GABA ratio and [(35)S]-tert-butylcyclophosphorothionate binding data revealed an efficacy profile of partial inverse agonists/antagonists for compounds 1c,e,f,j,k, and of a partial agonist for 2c. This last compound proved to be effective in antagonizing pentylenetetrazole-induced seizures in mice. Attempts were made to interpret the structure-affinity relationships of compounds V in the light of possible tautomeric equilibria involving the ligands.
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Affiliation(s)
- G Primofiore
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
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Dekermendjian K, Kahnberg P, Witt MR, Sterner O, Nielsen M, Liljefors T. Structure-activity relationships and molecular modeling analysis of flavonoids binding to the benzodiazepine site of the rat brain GABA(A) receptor complex. J Med Chem 1999; 42:4343-50. [PMID: 10543878 DOI: 10.1021/jm991010h] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The affinities for the benzodiazepine binding site of the GABA(A) receptor of 21 flavonoids have been studied using [(3)H]flumazenil binding to rat cortical membranes in vitro. We show that flavonoids with high affinity for the benzodiazepine receptor in vitro spanning the whole efficacy range from agonists (1q) to inverse agonists (1l) can be synthesized. The receptor binding properties of the flavonoids studied can successfully be rationalized in terms of a comprehensive pharmacophore model recently developed by Cook and co-workers (Drug Des. Dev. 1995, 12, 193-248), supporting the validity of this model. However, in contrast to the requirement by the model that an interaction with the hydrogen bond-accepting site A2 is necessary for compounds to display inverse agonistic activity, 6-methyl-3'-nitroflavone (1l), which cannot engage in such an interaction, nevertheless displays inverse agonism. The analysis of the binding affinities of 3'- and 4'-substituted flavones in terms of the pharmacophore model has yielded new information for the further development of the pharmacophore model.
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Affiliation(s)
- K Dekermendjian
- Research Institute of Biological Psychiatry, Sct. Hans Hospital, DK-4000 Roskilde, Denmark.
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