rimorphin and Disease-Models--Animal

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

Rats exposed to learned helplessness (LH), an animal model of depression, showed a recovery following an intracerebroventricular injection of nor-binaltorphimine dihydrochloride (norBNI; a kappa-opioid antagonist). To investigate the potential role of dynorphin A and dynorphin B, we examined the effects of different stress/depression models on dynorphin A and dynorphin B immunoreactivity in hippocampus and nucleus accumbens (NAc). Immobilization stress (3 h) caused an increase in levels of dynorphin A and dynorphin B immunoreactivity in the hippocampus and the NAc. Forced swim stress also temporally increased dynorphin A levels in the hippocampus. Furthermore, exposure to LH produced a similar increase in dynorphin A and dynorphin B in the hippocampus and NAc. Infusions of norBNI into the dentate gyrus or CA3 regions of hippocampus and into the shell or core regions of NAc produced antidepressant-like effects in the LH paradigm. The degrees of norBNI's effects were stronger in the CA3 region and NAc shell and less effective in the dentate gyrus of hippocampus and NAc core. These results indicate that both dynorphin A and dynorphin B contribute to the effects of stress, and suggest that blockade of kappa-opioid receptors may have therapeutic potential for the treatment of depression.

Topics: Animals; Behavior, Animal; Cell Count; Disease Models, Animal; Dose-Response Relationship, Drug; Dynorphins; Endorphins; Escape Reaction; Helplessness, Learned; Immobilization; Immunohistochemistry; Limbic System; Male; Naltrexone; Rats; Rats, Sprague-Dawley; Stress, Physiological

The influence of chronic arthritic pain on two endogenous opioid peptides, dynorphin B and [Met5]enkephalin-Arg6-Phe7, and multiple opioid receptors in discrete brain, lumbar spinal cord and pituitary pools was investigated. Using radioimmunoassay and receptor binding assay, we examined the changes in regional opioid peptide levels and opioid receptor activity due to chronic inflammation in adjuvant arthritic rats. At 4 weeks post-inoculation, increased levels of immunoreactive dynorphin B and [Met5]enkephalin-Arg6-Phe7 were measured in tissues of arthritic rats compared with controls. No significant changes in mu-, delta- or kappa-opioid receptors were seen after chronic inflammation. Taken together, these results indicate that in chronic arthritis, opioid receptor changes do not follow the peptide alterations of pro-dynorphin and pro-enkephalin systems. Thus, dynamic modification and modulation of nociceptive information takes place during chronic inflammation. This supports the key role of the central nervous system in chronic inflammatory pain conditions.

Topics: Animals; Brain; Chronic Disease; Disease Models, Animal; Dynorphins; Endorphins; Enkephalin, Methionine; Female; Inflammation; Opioid Peptides; Pain; Pain Measurement; Rats; Rats, Inbred Lew; Receptors, Opioid; Spinal Cord

While the morphometry of classical transmitter systems has been extensively studied, relatively little quantitative information is available on the subcellular distribution of peptidergic dense core vesicles (DCVs) within axonal arbors and terminals, and how distribution patterns change in response to neural activity. This study used correlated quantitative light and electron microscopic immunohistochemistry to examine dynorphin B-like immunoreactivity (dyn B-LI) in the rat hippocampal mossy fiber pathway before and after seizures. Forty-eight hours after seizures induced by two pentylenetetrazol injections, light microscopic dyn B-LI was decreased dorsally and increased ventrally. Ultrastructural examination indicated that, in the hilus of the dentate gyrus, these alterations resulted from changes that were almost entirely restricted to the profiles of the large mossy-like terminals formed by mossy fiber collaterals (which primarily contact spines), compared to the profiles of the smaller, less-convoluted terminals found on the same collaterals (which primarily contact aspiny dendritic shafts). Dorsally, mossy terminal profile labeled DCV (/DCV) density dropped substantially, while ventrally, both mossy terminal profile perimeter and /DCV density increased. In all terminal profile examined, /DCVs also were closely associated with the plasma membrane. Following seizures, there was a reorientation of /DCVs along the inner surface of mossy terminal profile membranes, in relation to the types of profiles adjacent to the membrane: in both the dorsal and ventral hilus, significantly fewer /DCVs were observed at sites apposed to dendrites, and significantly more were observed at sites apposed to spines. Thus, after seizures, changes specific to: (1) the dorsoventral level of the hippocampal formation, (2) the type of terminal, and (3) the type of profile in apposition to the portion of the terminal membrane examined were all observed. An explanation of these complex, interdependent alterations will probably require evoking multiple interrelated mechanisms, including selective prodynorphin synthesis, transport, and release.

Topics: Animals; Disease Models, Animal; Dynorphins; Endorphins; Immunohistochemistry; Linear Models; Male; Microscopy, Electron; Mossy Fibers, Hippocampal; Neuropeptides; Neurotransmitter Agents; Rats; Rats, Sprague-Dawley; Seizures