Effect of alpha-7 nicotinic acetylcholine receptor activation on beta-amyloid induced recognition memory impairment. Possible role of neurovascular function

PURPOSE: To evaluate the effects of PHA-543613 (α7-nAChR agonist) and galantamine (acetylcholinesterase inhibitor (AChEI)) on recognition memory and neurovascular coupling (NVC) response in beta-amyloid (Aβ) 25-35-treated mice. METHODS: PHA-543613 (1 mg/kg, i.p.), and galantamine (3 mg/kg, s.c.), effects were tested in Aβ25-35 mice model of AD. α7-nAChR antagonist, methyllycaconitine (MLA) (1 mg/kg, i.p.), was used for evaluation of receptor blockade effects. Recognition memory in animals was assessed by the novel object recognition (NOR) task. NVC response was analyzed by laser-doppler flow meter in barrel cortex by whisker stimulation method. RESULTS: Both, PHA-543613 and galantamine improve recognition memory in Aβ-treated animals. However, the advantageous effects of PHA-543613 were significantly higher than galantamine. Also, pretreatment with MLA reversed both galantamine and PHA-543613 effects on NOR. Impaired NVC response in AD animals was improved by PHA-543613 and galantamine. However, MLA pretreatment disrupts this function. CONCLUSION: Activation of α7-nAChR improved recognition memory possible through enhancement of neurovascular response in Alzheimer's disease in animals.

In vitro activity of hypnophilin from Lentinus strigosus: a potential prototype for Chagas disease and leishmaniasis chemotherapy

Hypnophilin and panepoxydone, terpenoids isolated from Lentinus strigosus, have significant inhibitory activity onTrypanosoma cruzi trypanothione reductase (TR). Although they have similar TR inhibitory activity at 10 μg/mL (40.3 μM and 47.6 μM for hypnophilin and panepoxydone, respectively; ~100 percent), hypnophilin has a slightly greater inhibitory activity (~71 percent) on T. cruzi amastigote (AMA) growth in vitro as well as on in vitro phytohemagglutinin (PHA)-induced peripheral blood mononuclear (PBMC) proliferation (~70 percent) compared to panepoxydone (69 percent AMA inhibition and 91 percent PBMC inhibition). Hypnophilin and panepoxydone at 1.25 μg/mL had 67 percent inhibitory activity onLeishmania (Leishmania) amazonensis amastigote-like (AMA-like) growth in vitro. The panepoxydone activity was accompanied by a significant inhibitory effect on PHA-induced PBMC proliferation, suggesting a cytotoxic action. Moreover, incubation of human PBMC with panepoxydone reduced the percentage of CD16+ and CD14+ cells and down-regulated CD19+, CD4+ and CD8+ cells, while hypnophilin did not alter any of the phenotypes analyzed. These data indicate that hypnophilin may be considered to be a prototype for the design of drugs for the chemotherapy of diseases caused by Trypanosomatidae.

Evaluation of anti-Wnt/β-catenin signaling agents by pGL4-TOP transfected stable cells with a luciferase reporter system

Refractory and relapsed leukemia is a major problem during cancer therapy, which is due to the aberrant activation of Wnt/β-catenin signaling pathway. Activation of this pathway is promoted by wingless (Wnt) proteins and induces co-activator β-catenin binding to lymphoid enhancer factor (LEF)/T-cell factor protein (TCF). To provide a convenient system for the screening of anti-Wnt/β-catenin agents, we designed a bi-functional pGL4-TOP reporter plasmid that contained 3X β-catenin/LEF/TCF binding sites and a selectable marker. After transfection and hygromycin B selection, HEK 293-TOP and Jurkat-TOP stable clones were established. The luciferase activity in the stable clone was enhanced by the recombinant Wnt-3A (rWnt-3A; 100-400 ng/mL) and GSK3β inhibitor (2’Z,3’E)-6-bromoindirubin-3’-oxime (BIO; 5 µM) but was inhibited by aspirin (5 mM). Using this reporter model, we found that norcantharidin (NCTD; 100 µM) reduced 80 percent of rWnt-3A-induced luciferase activity. Furthermore, 50 µM NCTD inhibited 38 percent of BIO-induced luciferase activity in Jurkat-TOP stable cells. Employing ³H-thymidine uptake assay and Western blot analysis, we confirmed that NCTD (50 µM) significantly inhibited proliferation of Jurkat cells by 64 percent, which are the dominant β-catenin signaling cells and decreased β-catenin protein in a concentration-dependent manner. Thus, we established a stable HEK 293-TOP clone and successfully used it to identify the Wnt/β-catenin signaling inhibitor NCTD.

Prevención de adherencias peritoneales postoperatorias mediante uso de antagonista de receptores de neurokinina tipo 1 / Peritoneal adhesions prevention: neurokinin-1 receptor antagonist

Background: The fibrinolytic activity plays an important role in Peritoneal Adhesions (PA) develop-ment. It's well known that de substance P decreased the fibrinolysis by binding the neurokinin-1 receptor, improving the PA formation. Objectives: To evaluate the effectiveness of intraperitoneal treatment with a Neurokinin-1 receptor antagonist (NK-R1A) in peritoneal adhesión prevention in animal model. Materials and Methods: In 40 male wistar rats, PA were induced, and then randomly assigned to 2 groups: A group treated with Aprepitant (NK-Rl A), and a control group. The animals were killed at 7 or 14 postoperative day, and the number, severity and histopathology of PA were evaluated. Results: NK-Rl A decreased the number (40 percent less) and severity (p = 0.001) of PA when compare to control group. The NK-Rl A group had less PA in manipulated and no manipulated organs during surgery. Besides presented less fibrosis (p = 0.001), less inflamation (p = 0.005) and less vascular proliferation (p = 0.047) than control group. Conclusions: The NK-Rl A is effective as in PA prevention.

Introducción: La actividad fibrinolítica juega un papel fundamental en el desarrollo de las adherencias peritoneales (AP), y se conoce que la Sustancia P al actuar sobre receptores de neurokinina tipo 1 a nivel peritoneal, disminuye la fibrinólisis, favoreciendo la formación de las mismas. Objetivos: Evaluar la efectividad del tratamiento intraperitoneal con antagonista de receptores 1 de neurokinina (NK-R1A) en la prevención de AP en modelo animal. Materiales y Métodos: A 40 ratas wistar se les practicó cirugía formadora de AP y fueron distribuidas de forma aleatoria en 2 grupos, un grupo que recibió Aprepitant (NK-R1A), y el otro como grupo control. Los animales fueron sacrificados a los 7 ó 14 días, y se evaluó el número, severidad e histopatología de las AP. Resultados: El NK-Rl A disminuyó el número (40 por ciento menos) y severidad de las AP (p = 0,001) en relación al grupo control y presentó menos AP en órganos manipulados y no manipulados durante la cirugía. Ademßs presentó menor grado de fibrosis (p = 0,001), menor inflamación (p = 0,005) y menor proliferación vascular (p = 0,047) que el grupo control. Conclusión: El tratamiento peritoneal con NK-R1A es eficaz en la prevención de la formación de AP.