ABSTRACT
In Alzheimer's disease (AD), microglia are involved in synaptic pruning and mediate synapse loss. LINGO-1 is a negative regulator of nerve growth, and whether antagonizing LINGO-1 can attenuate synaptic pruning by microglia and rescue dendritic spines in the hippocampus in AD is still unclear. On this basis, the anti-LINGO-1 antibody, which binds to LINGO-1 protein and antagonizes the effects of LINGO-1, was administered to 10-month-old APP/PS1 transgenic mice for 2 months. The Morris water maze test, immunohistochemical and stereological methods, immunofluorescence and 3D reconstruction were used. Compared to wild-type mice, APP/PS1 transgenic mice had worse performance on behavioral tests, fewer dendritic spines but more microglia in the hippocampus. Meanwhile, the microglia in APP/PS1 transgenic mice had more branches of medium length (4-6 µm) and a cell body area with greater variability. Moreover, APP/PS1 transgenic mice had more postsynaptic termini colocalized with microglia in the hippocampus than wild-type mice. The anti-LINGO-1 antibody significantly reversed these changes in AD, indicating that the anti-LINGO-1 antibody can improve hippocampus-dependent learning and memory abilities and effectively rescue dendritic spines in the hippocampus of AD mice and that microglia might participate in this progression in AD. These results provide a scientific basis for further studying the mechanism of the anti-LINGO-1 antibody in AD and help to elucidate the role of LINGO-1 in the treatment of AD.
Subject(s)
Alzheimer Disease , Amyloid beta-Protein Precursor , Animals , Mice , Alzheimer Disease/metabolism , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Dendritic Spines/metabolism , Disease Models, Animal , Hippocampus/metabolism , Maze Learning , Mice, Transgenic , Microglia/metabolism , Presenilin-1/genetics , Presenilin-1/metabolismABSTRACT
In view of the negative regulatory effect of leucine-rich repeat and immunoglobulin-like domain-containing nogo receptor-interacting protein 1 (LINGO-1) on neurons, an antibody against LINGO-1 (anti-LINGO-1 antibody) was herein administered to 10-month-old APP/PS1 transgenic Alzheimer's disease (AD) mice for 2 months as an experimental intervention. Behavioral, stereology, immunohistochemistry and immunofluorescence analyses revealed that the anti-LINGO-1 antibody significantly improved the cognitive abilities, promoted adult hippocampal neurogenesis (AHN), decreased the amyloid beta (Aß) deposition, enlarged the hippocampal volume, and increased the numbers of total neurons and GABAergic interneurons, including GABAergic and CCK-GABAergic interneurons rich in cannabinoid type 1 receptor (CB1R), in the hippocampus of AD mice. In contrast, this intervention significantly reduced the number of GABAergic interneurons expressing LINGO-1 and CB1R in the hippocampus of AD mice. More importantly, we also found a negative correlation between LINGO-1 and CB1R on GABAergic interneurons in the hippocampus of AD mice, while the anti-LINGO-1 antibody reversed this relationship. These results indicated that LINGO-1 plays an important role in the process of hippocampal neuron loss in AD mice and that antagonizing LINGO-1 can effectively prevent hippocampal neuron loss and promote AHN. The improvement in cognitive abilities may be attributed to the improvement in AHN, and in the numbers of GABAergic interneurons and CCK-GABAergic interneurons rich in CB1Rs in the hippocampus of AD mice induced by the anti-LINGO-1 antibody. Collectively, the double target effect (LINGO-1 and CB1R) initiated by the anti-LINGO-1 antibody may provide an important basis for the study of drugs for the prevention and treatment of AD in the future.
Subject(s)
Antibodies, Monoclonal/pharmacology , Cognitive Dysfunction/metabolism , GABAergic Neurons/metabolism , Hippocampus/metabolism , Membrane Proteins/metabolism , Nerve Tissue Proteins/metabolism , Receptor, Cannabinoid, CB1/metabolism , Alzheimer Disease/genetics , Alzheimer Disease/metabolism , Animals , Antibodies, Monoclonal/therapeutic use , Cognitive Dysfunction/drug therapy , GABAergic Neurons/drug effects , Hippocampus/drug effects , Interneurons/drug effects , Interneurons/metabolism , Male , Membrane Proteins/antagonists & inhibitors , Mice , Mice, Transgenic , Nerve Tissue Proteins/antagonists & inhibitors , Neurogenesis/drug effects , Neurogenesis/physiology , Receptor, Cannabinoid, CB1/genetics , Receptor-Interacting Protein Serine-Threonine Kinase 2/genetics , Receptor-Interacting Protein Serine-Threonine Kinase 2/metabolismABSTRACT
INTRODUCTION: Acrolein (2-propenal) is a reactive α, ß-unsaturated aldehyde which causes a health hazard to humans. The present study focused on determining the protection offered by sulforaphane against acrolein-induced damage in peripheral blood mononuclear cells (PBMC). MATERIAL AND METHODS: Acrolein-induced oxidative stress was determined through evaluating the levels of reactive oxygen species, protein carbonyl and sulfhydryl content, thiobarbituric acid reactive species, total oxidant status and antioxidant status (total antioxidant capacity, glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase activity). Also, Nrf-2 expression levels were determined using western blot analysis. Acrolein-induced inflammation was determined through analyzing expression of cyclooxygenase-2 by western blot and PGE2 levels by ELISA. The protection offered by sulforaphane against acrolein-induced oxidative stress and inflammation was studied. RESULTS: Acrolein showed a significant (p < 0.001) increase in the levels of oxidative stress parameters and down-regulated Nrf-2 expression. Acrolein-induced inflammation was observed through upregulation (p < 0.001) of COX-2 and PGE2 levels. Pretreatment with sulforaphane enhanced the antioxidant status through upregulating Nrf-2 expression (p < 0.001) in PBMC. Acrolein-induced inflammation was significantly inhibited through suppression of COX-2 (p < 0.001) and PGE2 levels (p < 0.001). CONCLUSIONS: The present study provides clear evidence that pre-treatment with sulforaphane completely restored the antioxidant status and prevented inflammatory responses mediated by acrolein. Thus the protection offered by sulforaphane against acrolein-induced damage in PBMC is attributed to its anti-oxidant and anti-inflammatory potential.
ABSTRACT
We consider a two-dimensional system in which a dilute stream of particles collides with an oblique planar wall. Both collisions between particles and collisions between particles and the wall are inelastic. We perform numerical simulations in two dimensions and show that the mean force experienced by the wall can be a nonmonotonic function of the angle between the wall and the particle stream. We show that this occurs because particles that rebound from the wall can collide with incoming particles and be scattered. This kind of particle-particle collision can reduce the force experienced by the wall. We refer to this effect as shielding. Furthermore, we show that the force experienced by the wall may be an increasing, decreasing or nonmonotonic function of the restitution coefficient in particle-particle collisions. We derive an exact solution for the mean force on the wall if the system is dilute, and the theoretical prediction is found to be in good agreement with our numerical results. The theory allows us to explicitly quantify the effects of shielding, and thus to explain a number of interesting features. The theory generally provides a useful upper bound for the mean force.
