Understanding the Neurobiology of Cd200 and the Cd200 Receptor: A Therapeutic Target For Controlling Inflammation In Human Brains?

Abstract

CD200 and its receptor, CD200 receptor (CD200R), have uniaue roles in controlling damaging inflammatory processes. At present, the only identified function for CD200 is as a ligand for CD200R. These proteins interact resulting in the activation of anti-inflammatory signaling by CD200R-expressing cells. When this interaction becomes deficient with aging or disease, chronic inflammation occurs, Experimental animal studies have demonstrated the consequences of disrupting CD200–CD200R interactions in the brain, but there have been few studies in human brains. Deficiency in neuronal CD200 may explain the chronic inflammation in human neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease and multiple sclerosis; however, deficits in the microglial expression of CD200R may also be of functional significance. The purpose of this review is to assess the data regarding the role of CD200–CD200R interactions in relation to the brain in order to determine if this could be a therapeutic target for human brain diseases with inflammatory components, and what additional studies are needed.

Effects of silver nanoparticles on the interactions of neuron‐ and glia‐like cells: Toxicity, uptake mechanisms, and lysosomal tracking

“…We selected the Transwell system not only because it allows of cell‐cell simultaneous interaction, thus avoiding loss of short half‐life species such as ROS when using conditioned medium transfer system, but it also distinguishes the responses occurring in different kinds of cells after AgNP exposure. The system also can neglect the contribution of cell‐cell contact (such as disruption of CD200/CD200r between neurons and microglia) on indirect effects of NPs. To demonstrate the indirect AgNP effects on N2a cells, it is essential to prove significantly less amount of AgNPs in the N2a cells of Transwell insert than that in well plate.…”

Melatonin decreases brain apoptosis, oxidative stress, and CD200 expression and increased survival rate in mice infected by Venezuelan equine encephalitis virus

“…CD200 represents an immunosuppressive molecule when it interacts with its receptor (CD200R), decreasing the inflammatory response. 30 CD200 is expressed on neurons, 14 oligodendrocytes, and reactive astrocytes 15 but not on normal microglia; 31 however, microglia can express CD200 during inflammatory responses. 32 The expression of CD200R is mainly restricted to the myeloid lineage cells and microglia, 14,15 but not on neurons, 32 suggesting a neuronal inhibitory effect on inflammatory microglial activation.…”

M1 and M2 immune activation in Parkinson’s Disease: Foe and ally?

“…However, it is important to note that, especially in vivo , macrophages or microglia are not necessarily only M1 or only M2, but can exist as continuums of M1 and M2 responses (Vogel et al, 2013, Martinez and Gordon, 2014). The M2 activation states in chronic disease have been the subject of intense recent interest and extensively reviewed in a series of recent publications (Shechter and Schwartz, 2013, Walker and Lue, 2013, Jiang et al, 2014, Miron and Franklin, 2014, Murray et al, 2014, Plemel et al, 2014). …”