mrs-1220 and Disease-Models--Animal

Adenosine possesses potent anti-inflammatory properties which are partly mediated by G(i) -coupled adenosine A3 receptors (A3Rs). A3R agonists have shown clinical benefit in a number of inflammatory conditions although some studies in A3R-deficient mice suggest a pro-inflammatory role. We hypothesised that, in addition to cell signalling effects, A3R compounds might inhibit neutrophil chemotaxis by disrupting the purinergic feedback loop controlling leukocyte migration. Human neutrophil activation triggered rapid upregulation of surface A3R expression which was disrupted by pre-treatment with either agonist (Cl-IB-MECA) or antagonist (MRS1220). Both compounds reduced migration velocity and neutrophil transmigration capacity without impacting the response to chemokines per se. Similar effects were observed in murine neutrophils, while cells from A3R-deficient mice displayed a constitutively impaired migratory phenotype indicating compound-induced desensitisation and genetic ablation had the same functional outcome. In a dextran sodium sulphate-induced colitis model, A3R-deficient mice exhibited reduced colon pathology and decreased tissue myeloperoxidase levels at day 8 - consistent with reduced neutrophil recruitment. However, A3R-deficient mice were unable to resolve the dextran sodium sulphate-induced inflammation and had elevated numbers of tissue-associated bacteria by day 21. Our data indicate that A3Rs play a role in neutrophil migration and disrupting this function has the potential to adversely affect innate immune responses.

Topics: Adenosine; Adenosine A3 Receptor Agonists; Adenosine A3 Receptor Antagonists; Animals; Chemotaxis; Colitis; Dextran Sulfate; Disease Models, Animal; Humans; Immunity, Innate; Inflammation; Mice; Mice, Knockout; Neutrophils; Quinazolines; Receptor, Adenosine A3; Triazoles; Up-Regulation

Topics: Adenosine A2 Receptor Antagonists; Adenosine A3 Receptor Antagonists; Animals; Disease Models, Animal; Endotoxemia; Inosine; Inosine Monophosphate; Interleukin-10; Male; Mice; Mice, Inbred C57BL; Pneumonia, Pneumococcal; Quinazolines; Receptor, Adenosine A2A; Receptor, Adenosine A2B; Receptor, Adenosine A3; Signal Transduction; Streptococcus pneumoniae; Triazoles; Tumor Necrosis Factor-alpha

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

Adenosine is a major negative neuromodulator of synaptic activity in the central nervous system and can exert anticonvulsant and neuroprotective effects in many experimental models of epilepsy. Extracellular adenosine can be formed by a membrane-anchored enzyme ecto-5'-nucleotidase. The purposes of this study were to characterize the role of adenosine receptors in modulating status epilepticus (SE) induced by pilocarpine and evaluate its neuroprotective action. Ecto-5'-nucleotidase activity was studied during the different phases of pilocarpine-induced epilepsy in rats.. Adult rats were pretreated with different adenosinergic agents to evaluate the latency and incidence of SE induced by pilocarpine in rats. The neuroprotective effect also was evaluated.. A proconvulsant effect was observed with DPCPX and DMPX that reduced the latency of SE in almost all rats. Pretreatment with the MRS 1220 did not alter the incidence of SE but reduced the latency to develop SE. An anticonvulsant and neuroprotective effect was detected with R-PIA. Rats pretreated with R-PIA had a decreased number of apoptotic cells in the hippocampus, whereas pretreatment with DPCPX did not modify the hippocampal damage. An intensification of neuronal death was observed in the dentate gyrus and CA3 when rats were pretreated with DMPX. MRS-1220 did not modify the number of apoptotic cells in the hippocampus. An increase in the ecto-5 -nucleotidase staining was detected in the hippocampus during silent and chronic phases.. The present data show that adenosine released during pilocarpine-induced SE via A1-receptor stimulation can exhibit neuroprotective and anticonvulsant roles. Similar effects could also be inferred with A2a and A3 adenosinergic agents, but further experiments are necessary to confirm their roles. Ecto-5 -nucleotidase activity during silent and chronic phases might have a role in blocking spontaneous seizures by production of inhibitory neuromodulator adenosine, besides taking part in the mechanism that controls sprouting.

Topics: 5'-Nucleotidase; Adenosine; Animals; Dentate Gyrus; Disease Models, Animal; Epilepsy, Temporal Lobe; Hippocampus; In Situ Nick-End Labeling; Male; Neuronal Plasticity; Neuroprotective Agents; Pilocarpine; Purinergic P1 Receptor Antagonists; Quinazolines; Rats; Rats, Wistar; Receptors, Purinergic P1; Status Epilepticus; Synapses; Triazoles; Xanthines