APP96-110 Elicits Neuroprotective Effects Following Ischemic Insult in Animal Models.

Competitive amyloidogenic pathways play an important role in many neurological diseases such as the onset of various degenerative diseases and ischemic stroke. Overexpression of amyloid precursor protein (APP) and amyloid-beta is modulated via the amyloidogenic pathway, which plays a crucial role in neuroinflammation. During ischemic conditions, the activity of the anti-inflammatory non-amyloidogenic pathway decreases, thus increasing the activity of amyloidogenic pathway. The soluble alpha form of APP (sAPPα), formed via the non-amyloidogenic pathway, exhibits neuroprotective effects against neurological diseases. sAPPα is thought to have a modulatory effect on several cell survival pathways, including its ability to inhibit the phosphoinositide 3-kinases (PI3K) pathway, thereby inhibiting the inflammatory response. The APP derivative, APP96-110, could act as a functional substitute for native sAPPα. Herein, we investigated whether APP96-110 has neuroprotective effects against neuroinflammation and damage following cerebral ischemic stroke. Treatment with diluted APP96-110 (0.005 mg/kg) in mice after 30 min of transient middle cerebral artery occlusion (tMCAO) showed improved motor function and reduced expression of the inflammatory marker CD86. APP96-110 decreased the infarct size and induced an anti-inflammatory response by inhibiting the PI3K pathway. These results suggest that the treatment of APP96-110 is efficacious in reducing neuroinflammation and infarct size in ischemic stroke.

CCR4 and CCR5 Involvement in Monocyte-Derived Macrophage Migration in Neuroinflammation.

Microglia, resident macrophages in the brain, play major roles in neuroinflammation after an acute many neurological diseases, including stroke. Our recent animal stroke model showed that interleukin (IL)-4 and IL-13 released by microglia are converted into monocyte-derived macrophages. However, the correlation with the migration mechanism of these cells is still unclear. This study aimed to clarify the effect of these cells on their migration and to identify potential targets that influence neuroinflammatory conditions. Inflammatory conditions were induced by lipopolysaccharide (LPS) treatment in in vitro and in vivo models. Cell migration was observed using transwell assay, and target chemokines were screened using the proteome profiler array in the in vitro model. Intravital, IVIS, and CLARITY imaging were used in the in vivo model. After LPS (1 ng/ml) treatment in BV2 (microglia cell line) and J774 (monocyte/macrophage cell line) cells, BV2 migration was approximately two-fold more enhanced compared to J774 migration. Overall, six types of chemokine C-C motif ligands (CCLs) were detected from the BV2 conditioned medium with LPS. These CCLs were related to C-C motif receptor (CCR)4 and CCR5. In the in vivo model, CCR4 and CCR5 antagonist significantly inhibited the migration of monocyte-derived macrophages to brain tissue following LPS (5 µg) treatment. In conclusion, the chemokines released by microglia may influence migration of monocyte-derived macrophages in necroinflammation conditions inducted by microglial activation. CCR4 and CCR5 expressed on monocyte-derived macrophages interacted with these chemokines and induced migration. Therefore, CCR4 and CCR5 may be explored as new therapeutic targets for neuroinflammation.

Role of agmatine in the application of neural progenitor cell in central nervous system diseases: therapeutic potentials and effects.

Agmatine, the primary decarboxylation product of L-arginine, generated from arginine decarboxylase. Since the discovery of agmatine in the mammalian brain in the 1990s, an increasing number of agmatine-mediated effects have been discovered, demonstrating the benefits of agmatine on ischemic strokes, traumatic brain injury and numerous psychological disorders such as depression, anxiety, and stress. Agmatine also has cellular protective effects and contributes to cell proliferation and differentiation in the central nervous system (CNS). Neural progenitor cells are an important component in the recovery and repair of many neurological disorders due to their ability to differentiate into functional adult neurons. Recent data has revealed that agmatine can regulate and increase proliferation and the fate of progenitor cells in the adult hippocampus. This review aims to summarise and discuss the role of agmatine in the CNS; specifically, the effects and relationship between agmatine and neural progenitor cells and how these ideas can be applied to potential therapeutic application.