Differential utilization of the ethanolamine moiety of phosphatidylethanolamine derived from serine and ethanolamine during NGF-induced neuritogenesis of PC12 cells

Characterization of the lipidomic profile of BmN cells in response to Bombyx mori cytoplasmic polyhedrosis virus infection

Bombyx mori cytoplasmic polyhedrosis virus (BmCPV)that belongs to the genus Cypovirus in the family of Reoviridae is one of the problematic pathogens in sericulture. In our previous study, we have found that lipid-related constituents in the host cellular membrane are associated with the BmCPV life cycle. It is important to note that the lipids not only affect the cellular biological processes, they also impact the virus life cycle. However, the intracellular lipid homeostasis in BmN cells after BmCPV infection remains unclear. Here, the lipid metabolism in BmCPV-infected BmN cells was studied by lipidomics analysis. Our results revealed that the intracellular lipid homeostasis was disturbed in BmN cells upon BmCPV infection. Major lipids constituents in cellular membrane were found to be significantly induced upon BmCPV infection, which included triglycerides, phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, phospholipids, glucoside ceramide, monoetherphosphatidylcholin, ceramide, ceramide phosphoethanolamine and cardiolipin. Further analysis of the pathways related to these altered lipids (such as PE and PC) showed that glycerophospholipid metabolism was one of the most enriched pathways. These results suggested that BmCPV may manipulate the lipid metabolism of cells for their own interest. The findings may facilitate a better understanding of the roles of lipid metabolic changes during virus infection in future studies.

Differentiation of NSC-34 cells is characterized by expression of NGF receptor p75, glutaminase and NCAM L1, activation of mitochondria, and sensitivity to fatty acid intervention

Motor neuronal damage due to diseases, traumatic insults or de-afferentation of the spinal cord is often incurable because of poor intrinsic regenerative capacity. Hence, medical basic research has to provide a better understanding of development-/regeneration-related cellular processes as only way to develop new and successful therapeutic strategies. Here, we investigated the neuronal differentiation of the NSC-34 hybrid cell line, which is an accepted model for spinal cord motor neurons. Their differentiation was stimulated by switching from normal to differentiation medium and by supplementation with palmitic and oleic acid. To characterize neuro-differentiation of NSC-34 cells, expression of nicotinic acetylcholine receptor alpha 4, NGF p75 receptor, IGF I alpha receptor, glutaminase, NCAM L1, ADAM10 and myelin basic protein as well as activation of mitochondria were analyzed. Both switch from normal to differentiation medium and fatty acid application stimulated NSC-34 differentiation. Differentiation was characterized by diminishing expression of the nicotinic acetylcholine receptor alpha 4 and enhancing expression of the NGF receptor p75, of glutaminase, of NCAM L1 and it's partially transformation from the cell surface into the cell. Fatty acid intervention stabilized the expression of the nicotinic acetylcholine receptor alpha 4, diminished the expression of the NGF receptor p75, consolidated the expression profile of NCAM L1, and intensified the expression of the relevant for NCAM L1 cleavage ADAM10. However, NCAM L1 cleavage itself was unaffected by fatty acid intervention, as was the differentiation-relevant activation of mitochondria and their transformation into neuronal filopodia.

Analysis of glycerophospholipid metabolism after exposure to PCB153 in PC12 cells through targeted lipidomics by UHPLC-MS/MS

Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) that have neurotoxicity, reproductive toxicity, hepatotoxicity and immunotoxicity in both animals and humans. Few studies have focused on the changes to endogenous glycerophospholipid metabolism caused by PCB153. To evaluate the relationships between exposure to PCB153 and specific endogenous glycerophospholipid metabolism, an ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was implemented in this study. Twenty-two endogenous glycerophospholipids in PC12 cells were analyzed after exposure to PCB153 at dosages of 0.05 μg mL^-1, 0.5 μg mL^-1 or 20 μg mL^-1 for 120 h. PC(14:0/14:0), PE(16:0/18:1), PE(16:0/18:2), PS(18:0/18:1) and PI(16:0/18:1) were identified as potential biomarkers under the rules of t-test (P) value < 0.05 and variable importance at projection (VIP) value > 1. It was also found that the alterations at 0.05 μg mL^-1 and 20 μg mL^-1 PCB153 were similar at 120 h, while 0.5 μg mL^-1 PCB153 presented an opposite trend. Additionally, significant upregulation of PC, PE and PS with the same fatty acid chains of 18:0/18:2 was found after exposure to 0.05 μg mL^-1 and 20 μg mL^-1 PCB153 at 120 h. This study revealed that PCB153 exposure modulated 22 endogenous glycerophospholipids in PC12 cells and provided the basis for the further study of PCB153 on the effects of glycerophospholipids on PC12 cells.

Metabolism and functions of phosphatidylserine in mammalian brain

Phosphatidylserine (PtdSer) is involved in cell signaling and apoptosis. The mechanisms regulating its synthesis and degradation are still not defined. Thus, its role in these processes cannot be clearly established at molecular level. In higher eukaryotes, PtdSer is synthesized from phosphatidylethanolamine or phosphatidylcholine through the exchange of the nitrogen base with free serine. PtdSer concentration in the nervous tissue membranes varies with age, brain areas, cells, and subcellular components. At least two serine base exchange enzymes isoforms are present in brain, and their biochemical properties and regulation are still largely unknown because their activities vary with cell type and/or subcellular fraction, developmental stage, and differentiation. These peculiarities may explain the apparent contrasting reports. PtdSer cellular levels also depend on its decarboxylation to phosphatidylethanolamine and conversion to lysoPtdSer by phospholipases. Several aspects of brain PtdSer metabolism and functions seem related to the high polyunsaturated fatty acids content, particularly docosahexaenoic acid (DHA).