Platelet-activating factor contributes to the induction of long-term potentiation in the rat somatosensory cortex in vitro

Transcriptomic Analysis of Mecp2 Mutant Mice Reveals Differentially Expressed Genes and Altered Mechanisms in Both Blood and Brain

Rett syndrome is a rare neuropsychiatric disorder with a wide symptomatology including impaired communication and movement, cardio-respiratory abnormalities, and seizures. The clinical presentation is typically associated to mutations in the gene coding for the methyl-CpG-binding protein 2 (MECP2), which is a transcription factor. The gene is ubiquitously present in all the cells of the organism with a peak of expression in neurons. For this reason, most of the studies in Rett models have been performed in brain. However, some of the symptoms of Rett are linked to the peripheral expression of MECP2, suggesting that the effects of the mutations affect gene expression levels in tissues other than the brain. We used RNA sequencing in Mecp2 mutant mice and matched controls, to identify common genes and pathways differentially regulated across different tissues. We performed our study in brain and peripheral blood, and we identified differentially expressed genes (DEGs) and pathways in each tissue. Then, we compared the genes and mechanisms identified in each preparation. We found that some genes and molecular pathways that are differentially expressed in brain are also differentially expressed in blood of Mecp2 mutant mice at a symptomatic-but not presymptomatic-stage. This is the case for the gene Ube2v1, linked to ubiquitination system, and Serpin1, involved in complement and coagulation cascades. Analysis of biological functions in the brain shows the enrichment of mechanisms correlated to circadian rhythms, while in the blood are enriched the mechanisms of response to stimulus-including immune response. Some mechanisms are enriched in both preparations, such as lipid metabolism and response to stress. These results suggest that analysis of peripheral blood can reveal ubiquitous altered molecular mechanisms of Rett and have applications in diagnosis and treatments' assessments.

From peroxisomal disorders to common neurodegenerative diseases - the role of ether phospholipids in the nervous system

The emerging diverse roles of ether (phospho)lipids in nervous system development and function in health and disease are currently attracting growing interest. Plasmalogens, a subgroup of ether lipids, are important membrane components involved in vesicle fusion and membrane raft composition. They store polyunsaturated fatty acids and may serve as antioxidants. Ether lipid metabolites act as precursors for the formation of glycosyl-phosphatidyl-inositol anchors; others, like platelet-activating factor, are implicated in signaling functions. Consolidating the available information, we attempt to provide molecular explanations for the dramatic neurological phenotype in ether lipid-deficient human patients and mice by linking individual functional properties of ether lipids with pathological features. Furthermore, recent publications have identified altered ether lipid levels in the context of many acquired neurological disorders including Alzheimer's disease (AD) and autism. Finally, current efforts to restore ether lipids in peroxisomal disorders as well as AD are critically reviewed.

Platelet-activating factor attenuation of long-term potentiation in rat hippocampal slices via protein tyrosine kinase signaling

It is well established that HIV-1-infected mononuclear phagocytes release platelet activating factor (PAF) and elevated levels of PAF have been detected in blood and in the cerebrospinal fluid (CSF) of acquired immunodeficiency syndrome (AIDS) patients with HIV-associated neurocognitive disorders (HAND). It is our hypothesis that the elevated levels of PAF alter long-term potentiation (LTP) in the hippocampus, leading to neurocognitive dysfunction. To test this hypothesis, we studied the effects of PAF on LTP in the CA1 region of rat hippocampal slices. Our results showed incubation of hippocampal slices with PAF attenuated LTP. The PAF-mediated attenuation was blocked by ginkgolide B, a PAF receptor antagonist, suggesting PAF attenuation of LTP via PAF receptors. Application of lyso-PAF, an inactive PAF analog, had no apparent effect on LTP. Further investigation revealed an involvement of tyrosine kinase in PAF attenuation of LTP, which was demonstrated by lavendustin A (a specific protein tyrosine kinase inhibitor) blockage of PAF attenuation of LTP. As LTP is widely considered as the cellular and synaptic basis for learning and memory, the attenuation of LTP by PAF may contribute at least in part to the HAND pathogenesis.

Platelet-activating factor receptor affects food intake and body weight

"Let's Move!" is a comprehensive initiative, launched by the First Lady, Michelle Obama, dedicates to solving problems of obesity, which is growing in child. The life behaviors do affect obesity; however, the mechanistic insight in molecular level is still not clear. In this study, by continually monitoring mouse body weight under chow and high fat western diets as well as metabolic, physical activity and food intake behaviors assessed in a CLAMS Comprehensive Lab Animal Monitoring System, we demonstrated that the platelet-activating factor receptor (PTAFR) contributes to modification of life behaviors. PTAFR does not affect metabolism of ingested dietary fat and carbohydrate in young animals; however, Ptafr ablation dramatically increased weight gain without affecting adipose tissue accumulation. Ptafr^-/- mice possess new habits that increased food intake and decreased movement. Our studies suggest that regulation of PTAFR activity may be a novel strategy to control obesity in children or young adults.

Roles of the hippocampal formation in pain information processing

Pain is a complex experience consisting of sensory-discriminative, affective-motivational, and cognitive-evaluative dimensions. Now it has been gradually known that noxious information is processed by a widely-distributed, hierarchically- interconnected neural network, referred to as neuromatrix, in the brain. Thus, identifying the multiple neural networks subserving these functional aspects and harnessing this knowledge to manipulate the pain response in new and beneficial ways are challenging tasks. Albeit with elaborate research efforts on the cortical responses to painful stimuli or clinical pain, involvement of the hippocampal formation (HF) in pain is still a matter of controversy. Here, we integrate previous animal and human studies from the viewpoint of HF and pain, sequentially representing anatomical, behavioral, electrophysiological, molecular/biochemical and functional imaging evidence supporting the role of HF in pain processing. At last, we further expound on the relationship between pain and memory and present some unresolved issues.