323,044 research outputs found
SYNTHESIS AND PHARMACOLOGICAL CHARACTERIZATION OF RIBOSE-MODIFIED ADENOSINE DERIVATIVES AS P1 RECEPTOR LIGANDS
No full textAdenosine, the natural ligand of P1 receptors, is implicated in the control of many physiological and pathological conditions such as inflammation, pain, cardiovascular and central nervous system (CNS) diseases.1
P1 receptors belong to the large family of GPCR receptors and are divided in four subtypes: A1, A2A, A2B and A3 adenosine receptors (ARs). Even though a large number of P1 ligands have been synthesized and characterized byin vitro and in vivo pharmacological studies, only very few of them are commercially available.
Modifications at the ribose moiety and substitution at the N6-position of adenosine, lead to adenosine derivatives endowed with increased potency at A1 or A3AR. Our previous SAR studies showed that the replacement of OH at 5’-position of the ribose moiety of N6-substituted adenosine derivatives by a chlorine improved A1AR potency and selectivity versus A3AR, with 5′-chloro-5′-deoxy-N6-(±)-(endo- norborn-2-yl)-adenosine (5′Cl5′d-(±)-ENBA) as one of the most potent and selective A1AR agonists,2 while a 5’-C-ethyl-tetrazolyl moiety maintained the A1AR potency, but restored high A3AR affinity, leading to very potent dual A1AR and A3AR ligands.3 Interestingly, both modifications at 5’-position of adenosine derivatives brought to human A3AR antagonism.
In order to further explore the structural determinants of this class of P1 ligands, a new series of ribose- modified N6-substituted adenosine derivatives was synthesized and their pharmacological profile was assayed. The results of this study will be discussed.References
1. Jacobson KA, Muller CE, Neuropharmacology 2015, doi: 10.1016/J.neuropharm.2015.12.001.
2. (a) Franchetti, P.; Cappellacci, L.; Vita, P.; Petrelli, R.; Lavecchia, A.; Kachler, S.; Klotz, K.-N.; Marabese, I.; Luongo, L.; Maione, S.; Grifantini, M. J. Med. Chem. 2009, 52, 2393−2406. (b) Luongo, L.; Petrelli, R.; Gatta, L.; Giordano, C.; Guida, F.; Vita, P.; Franchetti, P.; Grifantini, M.; De Novellis, V.; Cappellacci, L.; Maione, S. Molecules 2012, 17, 13712−13726. (c) Luongo, L.; Guida, F.; Imperatore, R.; Napolitano, F.; Gatta, L.; Cristino, L.; Giordano, C.; Siniscalco, D.; Di Marzo, V.; Bellini, G.; Petrelli, R.; Cappellacci, L.; Usiello, A.; de Novellis, V.; Rossi, F.; Maione, S. Glia 2014, 62, 122−132.
3. Petrelli, R.; Torquati, I.; Kachler, S.; Luongo, L.; Maione, S.; Franchetti, P.; Grifantini, M.; Novellino, E.; Lavecchia, A.; Klotz, K.-N-; Cappellacci, L. J. Med. Chem. 2015, 58, 2560-2566
Effects of 5'-chloro-5'-deoxy-N6-(±)-endo-norbornyl-adenosine, a potent and highly selective A1 adenosine receptor agonist, on neuropathic pain-induced behavioural and morphological changes in spinal microglia
No full textThis study was undertaken in order to investigate the effect of chronic treatment with 5'-chloro-5'-deoxy-N6-(±)-endo-norbornyladenosine (5'Cl5'd-(±)-ENBA),1 a potent and highly selective adenosine A1 receptor agonist, on thermal hyperalgesia and mechanical allodynia in a mouse model of neuropathic pain, the spared nerve injury (SNI). Chronic systemic administrations of 5'Cl5'd-(±)-ENBA (0.5 mg/kg, i.p once a day) reduced both thermal hyperalgesia and mechanical allodynia 3 and 7 days after SNI, in a way prevented by DPCPX (3 mg/kg, i.p.), a selective A1 receptor antagonist. SNI induced spinal changes on microglial activation ipsilaterally to the nerve injury. Moreover, 5'Cl5'd-(±)-ENBA significantly reduced microglial activation in vitro. In particular pre-incubation with 5'Cl5'd-(±)-ENBA prevented the microglial morphological changes induced by LPS, ATP, LPS+ATP challenges. Our results demonstrated an involvement of A1 receptors in the increase of nociceptive thresholds and in spinal changes occurred in neuropathic pain. In addition, 5'Cl5'd-(±)-ENBA antiallodynic and antihyperalgesic effects could be mediated by the A1 receptors expressed on microglial cells.
(1) Franchetti, P.; Cappellacci, L.; Vita, P.; Petrelli, R.; Lavecchia, A.; Kachler, S.; Klotz, K.-N.; Marabese, I.; Luongo, L.; Maione, S.; Grifantini, M. J. Med. Chem. 2009, 52, 2393-2406
SYNTHESIS AND BIOLOGICAL EVALUATION OF NOVEL A1 ADENOSINE RECEPTOR AGONISTS
No full textA1 adenosine receptor (A1AR) is the best characterized subtype of the four known adenosine receptors.1 Selective A1AR agonists show neuro- and cardio-protective effects, reduce intraocular pressure in glaucoma, and have anticonvulsivant activity. The majority of A1AR agonists are adenosine derivatives and even though many efforts have been carried out, only few drugs in advanced clinical studies are A1AR agonists. The main
problem is represented by the significant cardiovascular side effects (bradicardia and hypotension).1 In our previous studies we found that the replacement of the 5’-hydroxy-group by a chlorine atom in N6-substituted adenosine derivatives, improved both the A1AR affinity and selectivity. 5’-Chloro-5’-deoxy-N6-(±)-endo-
norbornyl-adenosine (5’Cl5’d-(±)-ENBA) resulted a potent and highly selective A1AR2 agonist showing
analgesic effects in a mice model of neuropathic pain.3 Interestingly, at analgesic doses it did not lower blood pressure and locomotor activity in mice.3 Moreover, it reduced dyskinesia evoked by L-DOPA in a mice model of Parkinson disease.4
Based on these interesting findings, a novel series of 5’-modified N6-substitued adenosine derivatives was synthesized and tested in human A1, A2A, A2B, and A3 adenosine receptors binding assay. The most potent and

selective compounds of the series were also assayed in a formalin test in mice. The results of this work will be discussed.
1Fredholm, B.B.; IJzerman, A.P.; Jacobson, K.A.; Linden, J.; Muller, C.E. Pharmacol. Rev. 2011, 63, 1-34.
2Franchetti, P.; Cappellacci, L.; Vita, P.; Petrelli, R.; Lavecchia, A.; Kachler, S.; Klotz, K.-N.; Marabese, I.; Luongo, L.; Maione, S.;
Grifantini, M. J. Med. Chem. 2009, 52, 2393−2406.
3(a) Luongo, L.; Petrelli, R.; Gatta, L.; Giordano, C.; Guida, F.; Vita, P.; Franchetti, P.; Grifantini, M.; De Novellis, V.; Cappellacci, L.; Maione, S. Molecules 2012, 17, 13712−13726. (b) Luongo, L.; Guida, F.; Imperatore, R.; Napolitano, F.; Gatta, L.; Cristino, L.; Giordano, C.; Siniscalco, D.; Di Marzo, V.; Bellini, G.; Petrelli, R.; Cappellacci, L.; Usiello, A.; de Novellis, V.; Rossi, F.; Maione, S. Glia 2014, 62, 122−132.
4Mango, D.; Bonito-Oliva, A.; Ledonne, A.; Cappellacci, L.; Petrelli, R.; Nisticò, R.; Berretta, N.; Fisone, G.; Mercuri, N.B. Exp. Neurol. 2014, 261, 733−743
Novel N6/5’-Disubstituted Adenosine Derivatives As A1 Adenosine Receptor Agonists: Synthesis, Binding Assay And Antinociceptive Activity
No full textAdenosine is a regulatory nucleoside that can be generated in response to cellular stress and tissue damage as well as during episodes of tissue hypoxia or inflammation. It acts on specific G-protein coupled receptors that have been classified into four subtypes (A1, A2A, A2B and A3) on the basis of their structures and signal transduction systems.
Selective A1 adenosine receptor (A1AR) agonists have antinociceptive, antiarrhythmic and neuro- and cardioprotective effects. There is a large body of evidence to suggest that A1AR agonists produce antinociception at spinal cord level as well as at supraspinal level. Our previous work showed that replacement of the 5′ -hydroxy-group by a chlorine atom in N6-substituted adenosine derivatives increased selectivity for A1AR [1]. 5′-Chloro-5′-deoxy-N6-(±)-(endo-norborn-2-yl)-adenosine (5′Cl5′d-(±)- ENBA) displayed high A1AR affinity and selectivity. It was shown to reduce both mechanical allodynia and thermal hyperalgesia in a mice model of neuropathic pain without affecting motor and cardiovascular functions [2]. Moreover, it reduced dyskinesia evoked by L-DOPA in a mice model of Parkinson’s disease [3].
In this work, novel N6/5’-disubstituted adenosine derivatives were synthesized and evaluated for analgesic activity in a formalin test in mice. The most potent compound of the series was found to inhibit the second phase of the nocifensive response induced by intrapaw injection of formalin at a dose of 2 mg/kg i.p. [2] Franchetti, P.; Cappellacci, L.; Vita, P.; Petrelli, R.; Lavecchia, A.; Kachler, S.; Klotz, K.-N.; Marabese, I.; Luongo, L.; Maione, S.; Grifantini, M. J. Med. Chem. 2009, 52, 2393−2406.
[3] (a) Luongo, L.; Petrelli, R.; Gatta, L.; Giordano, C.; Guida, F.; Vita, P.; Franchetti, P.; Grifantini, M.; De Novellis, V.; Cappellacci, L.; Maione, S. Molecules 2012, 17, 13712−13726. (b) Luongo, L.; Guida, F.; Imperatore, R.; Napolitano, F.; Gatta, L.; Cristino, L.; Giordano, C.; Siniscalco, D.; Di Marzo, V.; Bellini, G.; Petrelli, R.; Cappellacci, L.; Usiello, A.; de Novellis, V.; Rossi, F.; Maione, S. Glia 2014, 62, 122−132.
[4] Mango, D.; Bonito-Oliva, A.; Ledonne, A.; Cappellacci, L.; Petrelli, R.; Nisticò, R.; Berretta, N.; Fisone, G.; Mercuri, N.B. Exp. Neurol. 2014, 261, 733−743
5’-deoxy-5’-N-pyrazolyl-N6-substituded adenosine derivates as A1 adenosine receptor agonists: synthesis and antinociception in mice
No full textAdenosine receptors (ARs) are widely distributed throughout the body and are present in basically all cells, making them an interesting target for pharmacologic intervention in many pathophysiologic conditions. ARs belong to the family of G-protein coupled receptors (GPCRs) and are divided in four subtypes: A1, A2A, A2B and A3.
A1AR agonists are known to have antiarrhythmic, antinociceptive, anticonvulsant effects and to mediate neuroprotective effects through microglial cells. Moreover, A1AR agonists reduce lipolysis in adipose tissue and reduce elevated intraocular pressure (IOP) in glaucoma. Selectivity for the A1AR may be achieved by substitution of the N6-position of adenosine with a wide range of cycloalkyl-, bicycloalkyl-, and arylalkyl groups. Moreover, modifications at the ribose moiety contributes to A1AR affinity, selectivity, and efficacy, leading to full or partial A1 agonists [1]. Our previous work showed that replacement of the 5′-hydroxy group by a chlorine atom in N6-substituted adenosine derivatives increased selectivity for A1AR [2]. 5′-Chloro-5′-deoxy-N6-(±)-(endo- norborn-2-yl)-adenosine (5′Cl5′d-(±)-ENBA) displayed high A1AR affinity and selectivity. It was shown to reduce both mechanical allodynia and thermal hyperalgesia in a mice model of neuropathic pain without affecting motor and cardiovascular functions [3] and to reduce dyskinesia evoked by L-DOPA in a mice model of Parkinson’ s disease [4].
As part of our interest in identifying potent and selective A1AR agonists, we were interested in novel nucleosides modified in 5’- and N6- positions. In particular, 5’-deoxy-5’-N-pyrazolyl- N6-substituted adenosine derivatives were synthesized and tested in binding assays and in formalin test in mice. Based on our previous results on 5′Cl5′d-(±)-ENBA, we also tested the intermediates for the synthesis of the designed compounds, i.e. the 5’-deoxy-5’-chloro-N6- substituted adenosine derivatives. The results of our biological evaluation will be presented. [1] Cappellacci L, Petrelli R, Klotz K-N et al. Bioorg. Med. Chem. 2008, 16, 336.
[2] Franchetti P, Cappellacci L, Petrelli R, Klotz, K-N et al. J. Med. Chem. 2009, 52, 2393.
[3] (a) Luongo L, Petrelli R, Cappellacci L, Maione S et al. Molecules 2012, 17, 13712 (b) Luongo L, Petrelli R, Cappellacci L, Maione S. et al. Glia 2014, 62, 122.
[4] Mango D, Cappellacci L, Petrelli R, Mercuri NB et al. Exp. Neurol. 2014, 261, 733.
This work was supported by the Italian MIUR fund (PRIN2009, prot. no. 200928EEX4_004 to P.R.
5'-CHLORO-5'-DEOXY-N6-(±)-endo-NORBORNYLADENOSINE, A POTENT AND HIGHLY SELECTIVE HUMAN A1 ADENOSINE RECEPTOR AGONIST, PREVENTS HYPERALGESIA/ALLODYNIA AND EARLY OVER-EXPRESSION OF PRO-APOPTOTIC AND PRO-INFLAMMATORY GENES IN A MICE MODEL OF NEUROPATHIC PAIN
No full textA1 adenosine receptor (A1AR) is a promising drug target for neuropathic pain treatment. Some N6-substituted adenosine derivatives as A1AR agonists have shown to modulate nociception in vivo. Recently, we reported 5'-chloro-5'-deoxy-N6-(±)-endo-norbornyladenosine (5'Cl5'd-(±)-ENBA) as a very potent and highly selective human A1AR agonist with antinociceptive effects in mice.1 In this study we used mice with sciatic nerve injury (spared nerve injury, SNI) and combined behavioural, molecular and morphological approaches to assess the involvement of A1AR in neuropathic pain-associated hyperalgesia and allodynia and spinal cord gliosis and neuro-inflammation.
Mechanical allodynia and thermal hyperalgesia developed 2-3 days after surgery. Morphological changes in the ipsilateral L4-L6 laminae I-II consisted of: i) increased TUNEL-positive profiles, ii) increased microglia activity, and iii) astrogliosis. Molecular expression data showed: 1) increased expression of pro-apoptotic and pro-inflammatory genes (bax, 325 ± 12%; caspase 7, 109 ± 17%; caspase 8, 133 ± 17%), 7 days after SNI. The selective A1AR agonist 5'Cl5'd-(±)-ENBA (1 mg/Kg i.p. once daily), reduced the development of thermal hyperalgesia and mechanical allodynia. This treatment in part normalized the spinal cord expression of bax, bcl-2 and caspases in SNI mice, and proved to be cytoprotective at 7 days post-SNI. This study shows that: a) allodynia and hyperalgesia developed with spinal cord glia activation, b) over-expression of pro-apoptotic or pro-inflammatory genes may be critical for maintaining gliosis in the spinal cord, and c) adenosine A1 receptor stimulation was capable to protect neuropathic mice from the observed biomolecular and morphological modifications.
(1) Franchetti, P.; Cappellacci, L.; Vita, P.; Petrelli, R.; Lavecchia, A.; Kachler, S.; Klotz, K.-N.; Marabese, I.; Luongo, L.; Maione, S.; Grifantini, M. J. Med. Chem. 2009, 52, 2393-2406
Highly potent dual acting A1 and A3 adenosine receptor ligands: synthesis, binding, functional assays and analgesic effects in mice
No full textAdenosine (Ado) is a purine nucleoside endowed with many different physiological and pathological functions. Many studies support the fact that Ado acts as a neurotrasmitter and neuromodulator, and as an endogenous agonist on adenosine receptors (ARs). ARs belong to the superfamily of G-protein- coupled receptors (GPCRs) and are represented by four subtypes: A1, A2A, A2B, and A3 ARs (1). They are found in almost all kind of tissue: central nervous system (CNS), peripheral neurons, cardiovascular system, respiratory tract and immune system (2). Due to the wide distribution of ARs throughout the body, there is a substantial possibility that Ado ligands will have unwanted effects in non target tissues.
One way to overcome adverse effects is the use of multitarget drugs (3). A multitarget drug may display an improved therapeutic efficacy compared to a highly selective one. In fact, multitarget activities may potentiate the effect of treatment either additively or synergistically. Moreover, a multitarget drug has the advantage of following only one pharmacokinetic and metabolic pattern, thus overcoming the limits of combination therapy.
Substitutions at both purine and sugar moiety of adenosine results on AR ligands endowed with different affinity and selectivity at the four AR subtypes (4). Potent and highly selective A1AR agonists have been previously obtained by replacement of the 5’-hydroxyl group with a chlorine atom in N6-substituted-adenosine derivatives (5). 5’-Chloro-5’-deoxy-N6-(±)-(endo-norborn-2-yl)- adenosine (5’Cl5’d-(±)-ENBA) showed analgesic effects in mice without affecting cardiovascular and motor functions (6).
Combining a 5’-C-ethyltetrazol-2-yl group with the appropriate N6-substitution in adenosine derivatives led to an increased affinity versus both hA1AR and hA3AR, reaching subnanomolar values, while remaining agonists at hA1 and antagonists at hA3AR (7).
In this work a new series of 5’-C-ethyltetrazol-2-yl-N6-substituted adenosine derivatives were synthesized and studied both in vitro in binding and functional assays and in vivo in a mouse model of pain. Through an in silico receptor-driven approach, the molecular bases of the hA1- and hA3AR recognition and activation of this series of 5’-C-ethyl-tetrazolyl derivatives were explained.
References: 1. Fredholm, B. B.; IJzerman, A. P.; Jacobson, K. A.; Linden, J.; Muller, C. Pharmacol. Rev. 2011, 63, 1-34. 2. Jacobson, K. A.; Muller, C. E. Neuropharmacology 2016, 104, 31-49. 3. Anighoro, A.; Bajorath, J.; Rastelli, G. J. Med. Chem. 2014, 57, 7874-7887. 4. Petrelli, R.; Grifantini, M.; Cappellacci, L. Curr. Med. Chem. 2016, 23, 3118-3135. 5. Franchetti, P.; Cappellacci, L.; Vita, P.; Petrelli, R.; Lavecchia, A.; Kachler, S.; Klotz, K.-N.; Marabese, I.; Luongo, L.; Maione, S.; Grifantini, M. J. Med. Chem. 2009, 52, 2393-2406. 6. Luongo, L.; Petrelli, R.; Gatta, L.; Giordano, C.; Guida, F.; Vita, P.; Franchetti, P.; Grifantini, M.; De Novellis, V.; Cappellacci, L.; Maione, S. Molecules 2012, 17, 13712-13726. 7. Petrelli, R.; Torquati, I.; Kachler, S.; Luongo, L.; Maione, S.; Franchetti, P.; Grifantini, M.; Novellino, E.; Lavecchia, A.; Klotz, K.- N.; Cappellacci, L. J. Med. Chem. 2015, 58, 2560-2566
Cytostatic hetero-fused 7-deazapurine nucleosides, pharmacology, metabolism and mechanism of action.
No full textRecently we discovered that hetero-fused 7-deazapurine nucleosides exert nanomolar cytostatic activity, but their biological target and mechanism of action are unknown. Therefore, we propose to synthesize other analogues and derivatives, systematically study structure- activity relationship, intracellular metabolism, identify the cellular target(s) and the mode of action of these compounds, as well as their pharmacological properties (ADME), toxicity and in vivo activity, in order to optimize the lead structures and select candidates for preclinical development toward antitumor drugs
N6-substituted-5'-C-ethyi-tetrazolyl-adenosine derivatives: potent dual acting A1 and A3 adenosine receptor iigands with analgesic properties
No full textAdenosine (Ado) is the endogenous ligand of a family of G-protein coupied receptors (GPCRs) represented by four subtypes: Ai, A2A, A2B, and A3 adenosine receptors (ARs). They are widely distributed in all the human body including the central nervous system (CNS), peripheral neurons, cardiovascular system, respiratory tract and immune system [1].
Affinity and selectivity towards the four ARs can be modulated through substitutions at both purine and sugar moiety of adenosine. The replacement of the 5'-hydroxyl group with a chlorine atom in /V6-substituted adenosine derivatives led to discovery of 5'-chloro-5'-deoxy-/V6-(±)-(endo-norborn-2-yl)- adenosine (5'CI5'd-(±)-ENBA), a potent and selective A1AR agonist that showed analgesic effects in mice without affecting cardiovascular and motor functìons [2].
Introduction of a 5'-C-ethyltetrazol-2-yl group, together with the appropriate N6-substitution in adenosine derivatives, furnished compounds endowed with an increased affinity versus both hA1AR and hA3AR, reaching affinities in subnanomolar range [3].
In this work, a new series of 5'-C-ethyltetrazol-2-yl-N6-substituted adenosine derivatives were designed, synthesized and tested in vitro in binding and functional assays and in vivo in a mouse model of pain. The molecular features necessary for the hA1- and hA3AR recognition and activation by this series of derivatives were explained through an in silice receptor-driven approach. [1] K. A. Jacobson and C. E. Muller, Neuropharmacology 104(2016) 31-49.
[2] L. Luongo, R. Petrelli, L. Gatta, C. Giordano, F. Guida, P. Vita, P. Franchetti, M. Grifantini, V. De Novellls, L. Cappellacci, and S. Maione, Molecules 17 (2012) 13712-13726.
[3] R. Petrelli, I. Torquati, S. Kachler, L. Luongo, S. Maione, P. Franchetti, M. Grifantini, E. Novellino, A. Lavecchia, K.-N. Klotz, and L. Cappellacci, J. Med. Chem. 58 (2015) 2560-2566
5'-Chloro-5'-deoxy-N6-(±)-endo-norbornyladenosine, a potent and highly selective human A1 adenosine receptor agonist modulates neuropathic pain in mice.
No full textA1 adenosine receptors (A1ARs) are promising drug targets for neuropathic pain treatment. Some N6-substituted adenosine derivatives as A1AR agonists have shown to modulate nociception in vivo. Recently, we reported 5'-chloro-5'-deoxy-N6-(±)-endo-norbornyladenosine (5'Cl5'd-(±)-ENBA) as a very potent and highly selective human A1AR agonist with antinociceptive effects in mice.1 This study was undertaken to investigate the effect of 5'Cl5'd-(±)-ENBA on neuropathic pain. Mice with sciatic nerve injury (spared nerve injury, SNI) and combined behavioural, molecular and morphological approaches to assess the involvement of A1ARs in neuropathic pain-associated hyperalgesia, allodynia, spinal cord gliosis and neuro-inflammation, were used. It was found that A1AR stimulation with 5'Cl5'd-(±)-ENBA was capable to protect neuropathic mice from all those SNI-induced modifications.
1. Franchetti, P.; Cappellacci, L.; Vita, P.; Petrelli, R.; Lavecchia, A.; Kachler, S.; Klotz, K.-N.; Marabese, I.; Luongo, L.; Maione, S.; Grifantini, M. J. Med. Chem. published on Web 03/24/2009
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