Choline transport for phospholipid synthesis: An emerging role of choline transporter-like protein 1.
Ontology highlight
ABSTRACT:
SUBMITTER: Hedtke V
PROVIDER: S-EPMC6552397 | biostudies-literature | 2019 May
REPOSITORIES: biostudies-literature
Publications
Choline transport for phospholipid synthesis: An emerging role of choline transporter-like protein 1.
Hedtke Vera V Bakovic Marica M
Experimental biology and medicine (Maywood, N.J.) 20190218 8
<h4>Impact statement</h4>This review will provide a summary of recent advances in choline transport research and highlight important novel areas of focus in the field. ...[more]
Similar Datasets
Project description:Choline is an essential nutrient that is required for synthesis of the main eukaryote phospholipid, phosphatidylcholine. Macrophages are innate immune cells that survey and respond to danger and damage signals. Although it is well-known that energy metabolism can dictate macrophage function, little is known as to the importance of choline homeostasis in macrophage biology. We hypothesized that the uptake and metabolism of choline are important for macrophage inflammation. Polarization of primary bone marrow macrophages with lipopolysaccharide (LPS) resulted in an increased rate of choline uptake and higher levels of PC synthesis. This was attributed to a substantial increase in the transcript and protein expression of the choline transporter-like protein-1 (CTL1) in polarized cells. We next sought to determine the importance of choline uptake and CTL1 for macrophage immune responsiveness. Chronic pharmacological or CTL1 antibody-mediated inhibition of choline uptake resulted in altered cytokine secretion in response to LPS, which was associated with increased levels of diacylglycerol and activation of protein kinase C. These experiments establish a previously unappreciated link between choline phospholipid metabolism and macrophage immune responsiveness, highlighting a critical and regulatory role for macrophage choline uptake via the CTL1 transporter.
| S-EPMC6065184 | biostudies-literature
Project description:Synthesis of acetylcholine (ACh) by non-neuronal cells is now well established and plays diverse physiologic roles. In neurons, the Na(+) -dependent, high affinity choline transporter (CHT1) is absolutely required for ACh synthesis. In contrast, some non-neuronal cells synthesize ACh in the absence of CHT1 indicating a fundamental difference in ACh synthesis compared to neurons. The aim of this study was to identify choline transporters, other than CHT1, that play a role in non-neuronal ACh synthesis. ACh synthesis was studied in lung and colon cancer cell lines focusing on the choline transporter-like proteins, a five gene family choline-transporter like protein (CTL)1-5. Supporting a role for CTLs in choline transport in lung cancer cells, choline transport was Na(+) -independent and CTL1-5 were expressed in all cells examined. CTL1, 2, and 5 were expressed at highest levels and knockdown of CTL1, 2, and 5 decreased choline transport in H82 lung cancer cells. Knockdowns of CTL1, 2, 3, and 5 had no effect on ACh synthesis in H82 cells. In contrast, knockdown of CTL4 significantly decreased ACh secretion by both lung and colon cancer cells. Conversely, increasing expression of CTL4 increased ACh secretion. These results indicate that CTL4 mediates ACh synthesis in non-neuronal cell lines and presents a mechanism to target non-neuronal ACh synthesis without affecting neuronal ACh synthesis.
| S-EPMC3866050 | biostudies-literature
Project description:Macromolecular trafficking and cell-to-cell communication in plants occurs via plasmodesmata (PD). Currently, little is known about the proteins defining these sophisticated cell-to-cell contacts. To uncover proteins required for PD structure and function we made use of the 17 kDa movement protein (MP17) of the Potato leafroll virus (PLRV). The protein is required for cell-to-cell movement of the virus and localizes specifically to branched PD in source tissues. By forward genetic screening for Arabidopsis mutants with altered PD binding of MP17, several mutants were found. Map-based cloning of one of these mutants revealed a mutation in the choline transporter-like 1 (CHER1) protein. The mutation abolished plasma membrane localization of the protein. As consequence phosphatidylcholine levels and PD binding of MP17 decreased. Transcriptome analysis revealed a down-regulation of defense genes and genes involved in the synthesis of very long chain fatty acids, indicating an impairment of lipid signaling. Furthermore, cher1 mutants showed a reduced assimilate export and stunted growth. These findings highlight the emerging role of phospholipids, especially in the context of PD structure and function as well as potential binding sites for plasma membrane- and PD-associated proteins, which has been neglected for a long time. light exposed source leaves from wild type Col-0, T-DNA insertion line cher1-4 and mutant cher1-5 (10 weeks old). Samples: per pool 2 source leaves from 4 different plants, taken in the afternoon; wildtype (WT): Col-0, cher1-4: T-DNA insertion line SALK-065853 (ecotype Col-0, kanamycin resistance), cher1-5: Col-0 with GGA -->GAA at position 740 of cds
2016-06-01 | E-GEOD-61595 | biostudies-arrayexpress
Project description:Macromolecular trafficking and cell-to-cell communication in plants occurs via plasmodesmata (PD). Currently, little is known about the proteins defining these sophisticated cell-to-cell contacts. To uncover proteins required for PD structure and function we made use of the 17 kDa movement protein (MP17) of the Potato leafroll virus (PLRV). The protein is required for cell-to-cell movement of the virus and localizes specifically to branched PD in source tissues. By forward genetic screening for Arabidopsis mutants with altered PD binding of MP17, several mutants were found. Map-based cloning of one of these mutants revealed a mutation in the choline transporter-like 1 (CHER1) protein. The mutation abolished plasma membrane localization of the protein. As consequence phosphatidylcholine levels and PD binding of MP17 decreased. Transcriptome analysis revealed a down-regulation of defense genes and genes involved in the synthesis of very long chain fatty acids, indicating an impairment of lipid signaling. Furthermore, cher1 mutants showed a reduced assimilate export and stunted growth. These findings highlight the emerging role of phospholipids, especially in the context of PD structure and function as well as potential binding sites for plasma membrane- and PD-associated proteins, which has been neglected for a long time.
2016-06-01 | GSE61595 | GEO
Project description:The synaptic uptake of choline via the high-affinity, hemicholinium-3-dependent choline transporter (CHT) strongly influences the capacity of cholinergic neurons to sustain acetylcholine (ACh) synthesis and release. To advance research on the impact of CHT capacity in humans, we established the presence of the neuronal CHT protein in human T lymphocytes. Next, we demonstrated CHT-mediated choline transport in human T cells. To address the validity of T cell-based choline uptake as a proxy for brain CHT capacity, we isolated T cells from the spleen, and synaptosomes from cortex and striatum, of wild type and CHT-overexpressing mice (CHT-OXP). Choline uptake capacity in T cells from CHT-OXP mice was two-fold higher than in wild type mice, mirroring the impact of CHT over-expression on synaptosomal CHT-mediated choline uptake. Monitoring T lymphocyte CHT protein and activity may be useful for estimating human CNS cholinergic capacity and for testing hypotheses concerning the contribution of CHT and, more generally, ACh signaling in cognition, neuroinflammation and disease.
| S-EPMC5524217 | biostudies-literature
Project description:Bacterial microcompartments (MCPs) are widespread protein-based organelles that play important roles in the global carbon cycle and in the physiology of diverse bacteria, including a number of pathogens. MCPs consist of metabolic enzymes encapsulated within a protein shell. The main roles of MCPs are to concentrate enzymes together with their substrates (to increase reaction rates) and to sequester harmful metabolic intermediates. Prior studies indicate that MCPs have a selectively permeable protein shell, but the mechanisms that allow selective transport across the shell are not fully understood. Here we examine transport across the shell of the choline utilization (Cut) MCP of Escherichia coli 536, which has not been studied before. The shell of the Cut MCP is unusual in consisting of one pentameric and four hexameric bacterial microcompartment (BMC) domain proteins. It lacks trimeric shell proteins, which are thought to be required for the transport of larger substrates and enzymatic cofactors. In addition, its four hexameric BMC domain proteins are very similar in amino acid sequence. This raises questions about how the Cut MCP mediates the selective transport of the substrate, products and cofactors of choline metabolism. In this report, site-directed mutagenesis is used to modify the central pores (the main transport channels) of all four Cut BMC hexamers to assess their transport roles. Our findings indicate that a single shell protein, CmcB, plays the major role in choline transport across the shell of the Cut MCP and that the electrostatic properties of the CmcB pore also impact choline transport. The implications of these findings with regard to the higher-order structure of MCPs are discussed.
| S-EPMC10710832 | biostudies-literature
Project description:Inflammatory activity and hypoxia in atherosclerotic plaques are associated with plaque instability and thrombotic complications. Recent studies show that vascular cell metabolism affects atherogenesis and thrombogenicity. This study aimed to identify the metabolites in macrophage-rich unstable plaques that modulate atherogenesis and serve as potential markers of plaque instability. Atherosclerotic plaques were induced by balloon injury in the iliofemoral arteries of rabbits fed on a conventional or 0.5% cholesterol diet. At 3 months post-balloon injury, the arteries and cardiac tissues were subjected to histological, quantitative real-time polymerase chain reaction, and metabolomic analyses. The identified metabolite-related proteins were immunohistochemically analyzed in stable and unstable plaques from human coronary arteries. The factors modulating the identified metabolites were examined in macrophages derived from human peripheral blood mononuclear cells. Metabolomic analysis revealed that choline and guanine levels in macrophage-rich arteries were upregulated compared with those in non-injured arteries and cardiac tissues. Vascular choline levels, but not guanine levels, were positively correlated with the areas immunopositive for macrophages and tumor necrosis factor (TNF)-α and matrix metalloproteinase (MMP) 9 mRNA levels in injured arteries. In human coronary arteries, choline transporter-like protein (CTL) 1 was mainly localized to macrophages within plaques. The area that was immunopositive for CTL1 in unstable plaques was significantly higher than that in stable plaques. Intracellular choline levels were upregulated upon stimulation with TNF-α but were downregulated under hypoxia in cultured macrophages. Administration of choline upregulated the expression of TNF-α and CTL1 mRNA in cultured macrophages. The transfection of CTL1 small interfering RNA decreased CTL1, TNF-α, and MMP9 mRNA levels in cultured macrophages. These results suggest that choline metabolism is altered in macrophage-rich atherosclerotic lesions and unstable plaques. Thus, CTL1 may be potential markers of plaque instability.
| S-EPMC9937458 | biostudies-literature
Project description:The blood-brain barrier choline transporter (BBB-ChT) may have utility as a drug delivery vector to the central nervous system (CNS). We therefore initiated molecular docking studies with the AutoDock and AutoDock Vina (ADVina) algorithms to develop predictive models for compound screening and to identify structural features important for binding to this transporter. The binding energy predictions were highly correlated with r(2) =0.88, F=692.4, standard error of estimate =0.775, and P-value<0.0001 for selected BBB-ChT-active/inactive compounds (n=93). Both programs were able to cluster active (Gibbs free energy of binding <-6.0 kcal*mol(-1)) and inactive (Gibbs free energy of binding >-6.0 kcal*mol(-1)) molecules and dock them significantly better than at random with an area under the curve value of 0.86 and 0.84, respectively. In ranking smaller molecules with few torsional bonds, a size-related bias in scoring producing false-negative outcomes was detected. Finally, important blood-brain barrier parameters, such as the logBBpassive and logBBactive values, were assessed to predict compound transport to the CNS accurately. Knowledge gained from this study is useful to better understand the binding requirements in BBB-ChT, and until such time as its crystal structure becomes available, it may have significant utility in developing a highly predictive model for the rational design of drug-like compounds targeted to the brain.
| S-EPMC4159400 | biostudies-literature
Project description:Choline acetyltransferase (ChAT) synthesizes the neurotransmitter, acetylcholine, at cholinergic nerve terminals. ChAT contains nuclear localization signals and is also localized in the nuclei of neural and non-neuronal cells. Nuclear ChAT might have an as yet unidentified function, such as transcriptional regulation. In this study, we investigated the alteration of candidate gene transcription by ChAT. We chose high affinity choline transporter (CHT1) and vesicular acetylcholine transporter (VACHT) as candidate genes, which function together with ChAT in acetylcholine production. Using SH-SY5Y human neuroblastoma cells stably expressing wild-type human ChAT, we found that overexpressed ChAT enhanced transcription of the CHT1 gene but not the VACHT gene. In contrast, nuclear localization signal disrupted, and catalytically inactive mutant ChATs could not induce, CHT1 expression. Additionally, ChAT did not alter CHT1 expression in non-neuronal HEK293 cells. Our results suggest that ChAT activates the transcription of selected target genes in neuronal cells. Both enzymatic activity and nuclear translocation of ChAT are required for its transcriptional enhancement.
| S-EPMC3037696 | biostudies-literature
Project description:Lower rim carboxylic acid calix[n]arenes and upper rim phosphonic acid functionalized calix[4]arenes effect selective transport of distinct molecular payloads through a liquid membrane. The secret to this success lies in the attachment of a receptor-complementary handle. We find that the trimethylammonium ethylene group present in choline is a general handle for the transport of drug and drug-like species. Furthermore, neurotransmitters possessing ionizable amine termini are also transported. Some limitations to this strategy have been uncovered as payloads become increasingly lipophilic. These developments reveal new approaches to synthetic receptor-mediated selective small molecule transport in vesicular and cellular systems.
| S-EPMC4495001 | biostudies-literature