Patrizia Vita

5'-Chloro-5'-deoxy-(±)-ENBA, a Potent and Selective Adenosine A1 Receptor Agonist, Alleviates Neuropathic Pain in Mice Through Functional Glial and Microglial Changes without Affecting Motor or Cardiovascular Functions

This study was undertaken in order to investigate the effect of chronic treatment with 5′-chloro-5′-deoxy-(±)-ENBA, a potent and highly selective agonist of human adenosine A1 receptor, on thermal hyperalgesia and mechanical allodynia in a mouse model of neuropathic pain, the Spared Nerve Injury (SNI) of the sciatic nerve. Chronic systemic administration of 5′-chloro-5′-deoxy-(±)-ENBA (0.5 mg/kg, i.p.) reduced both mechanical allodynia and thermal hyperalgesia 3 and 7 days post-SNI, in a way prevented by DPCPX (3 mg/kg, i.p.), a selective A1 adenosine receptor antagonist, without exerting any significant change on the motor coordination or arterial blood pressure. In addition, a single intraperitoneal injection of 5′-chloro-5′-deoxy-(±)-ENBA (0.5 mg/kg, i.p.) 7 days post-SNI also reduced both symptoms for at least two hours. SNI was associated with spinal changes in microglial activation ipsilaterally to the nerve injury. Activated, hypertrophic microglia were significantly reduced by 5′-chloro-5′-deoxy-(±)-ENBA chronic treatment. Our results demonstrated an involvement of adenosine A1 receptor in the amplified nociceptive thresholds and in spinal glial and microglial changes occurred in neuropathic pain, without affecting motor coordination or blood pressure. Our data suggest a possible use of adenosine A1 receptor agonist in neuropathic pain symptoms.

Novel Inhibitors of Inosine Monophosphate Dehydrogenase in Patent Literature of the Last Decade

Inosine monophosphate dehydrogenase (IMPDH), an NAD-dependent enzyme that controls de novo synthesis of guanine nucleotides, has received considerable interest in recent years as an important target enzyme, not only for the discovery of anticancer drugs, but also for antiviral, antiparasitic, and immunosuppressive chemotherapy. The field of IMPDH inhibitor research is highly important for providing potential therapeutics against a validated target for disease intervention. This patent review examines the chemical structures and biological activities of recently reported IMPDH inhibitors. Patent databases SciFinder and Espacenet and Delphion were used to locate patent applications that were published between January 2002 and July 2012, claiming chemical structures for use as IMPDH inhibitors. From 2002 to 2012, around 47 primary patent applications have claimed IMPDH inhibitors, which we analyzed by target and applicant. The level of newly published patent applications covering IMPDH inhibitors remains high and a diverse range of scaffolds has been claimed.

Inhibition of HIV-1 Replication in Macrophages by Red Blood Cell-Mediated Delivery of a Heterodinucleotide of Lamivudine and Tenofovir

Homo- and heterodimers of nucleoside/nucleotide analogues as reverse transcriptase inhibitors are effective on HIV-1-infected human monocyte-derived macrophages (M/M) compared to the single drugs or their combination. Since the combined treatment of lamivudine (3TC) and tenofovir ((R)PMPA) has an antiretroviral efficacy and a synergic effect respect to separate drugs, the heterodinucleotide 3TCpPMPA was synthesized. A single administration of the dimer as free drug or 3TCpPMPA-loaded RBC selectively targeted to M/M was able to almost completely protect macrophages from “de novo” infection.

Ribose-modified mizoribine analogues : Synthesis and biological evaluation

Synthesis, conformational analysis and antitumor evaluation of 2′- and 3′-C-methyl analogues of mizoribine (bredinine, 4-carbamoyl-1-β-D-ribofuranosylimidazole-5-olate) are reported.

SYNTHESIS AND BIOLOGICAL EVALUATION OF NAD ANALOGS AS HUMAN PYRIDINE NUCLEOTIDE ADENYLYLTRANSFERASE INHIBITORS

NAD analogs modified at the ribose adenylyl moiety, named N-2′-MeAD and Na-2′-MeAD, were synthesized as ligands of pyridine nucleotide (NMN/NaMN) adenylyltransferase (NMNAT). Both dinucleotides resulted selective inhibitors against human NMNAT-3 isoenzyme.

Synthesis and Antitumor Activity of a Heterodinucleotide of BVDU and Gemcitabine

A heterodinucleotide comprising BVDU and Gemcitabine bound together by a 5′,5′-pyrophospate bridge (BVDUp2dFdC) has been synthesized and evaluated as antitumor agent against AH13 rat sarcoma cells. BVDUp2dFdC showed a cytotoxicity similar to that of Gemcitabine.

ATP-mimetics derived from 2 '(3 ')-C-methyladenosine as human P2Y2 agonists

P2X4 and P2X7 are the predominant purinergic receptor subtypes expressed in macrophages, microglia and epithelial cells, and they are potentially important therapeutic targets for treatment of pain and inflammation. For both subtypes, there is evidence that plasmamembrane expression is tightly regulated. P2X4 receptors are prominently localized to lysosomes and resist degradation by virtue of N-linked glycans decorating the intra-luminal loop of the receptor. P2X7 receptors are reported to be predominantly intracellular in monocytes and are upregulated at the plasma membrane upon differentiation of monocytes to macrophages. We have previously shown an interaction between P2X4 and P2X7 receptors, suggesting that they might form an association. The mechanisms that regulate their plasma membrane expression are not well understood, and we have used biochemical methods to look at the size and distribution of the native complexes in a variety of cell types in which they are co-expressed. We have compared the proportion of receptors expressed at the cell surface in cultured microglia and macrophages following exposure to modulators of microglial/macrophage activation. Surface expression was analysed by biotinylation of exposed proteins and by cross-linking proteins with membrane impermeant cross-linkers, followed by SDS-PAGE and western blotting. The modulators included lipopolysaccharide (LPS), ATP and phorbol esters. Cross-linking of surface receptors also provides a means of analysing the subunit composition of the complexes at the plasma membrane, based upon the size difference of P2X4 and P2X7 subunits. These results are compared with those obtained using blue native (BN)-PAGE analysis of the total P2X receptor population.Plenary Presentations The struggle to establish purinergic signalling Burnstock, Geoffrey Autonomic Neuroscience Centre Royal Free and University College Medical School, Rowland Hill Street, London NW3 2PF, UK Early experiments in the 1960’s will be described leading to the purinergic neurotransmission hypothesis proposed in 1972. The influence of publications by key figures such as Andrew Szent-Györgyi, Pamela Holton, Robert Berne, Mike Rand and Jack Eccles is recognised. Unfortunately, the hypothesis was regarded with scepticism by many for the next 25 years and stories of this resistance will be recounted. The cloning of receptors for purines and pyrimidines in the early 1990’s was an important turning point in the acceptance of the hypothesis and the important contributions of many outstanding scientists will be related. Current strong interest in the pathophysiological roles of purinergic signalling and exploration of the therapeutic potential for a number of disease conditions will be discussed. From chemoreception to eye development -fundamental roles of ATP signalling