Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1522282 (EMT)
 2,868 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Non-neuronal monoamine transporters OCT1, OCT2, and EMT, which are all members of the amphiphilic solute facilitator family, control signal transmission by removing released transmitters, such as dopamine, noradrenaline, adrenaline, 5-hydroxytryptamine, and histamine, from the extracellular space. In the current study, we have isolated human EMT (gene symbol SLC22A3) and OCT2 (SLC22A2) genes and report the gene and promoter organization. Both genes consist of 11 coding exons, with consensus GT/AG splice sites and conserved intron locations. The EMT gene is 77 kb, and the OCT2 gene is 45 kb in size. For the EMT gene, two transcription start points were identified by inverse polymerase chain reaction based on mRNA from Caki-1 cells. The EMT promoter, located within a CpG island, lacks a consensus TATA box but contains a prototypical initiator element and a number of potential binding sites for ubiquitous transcription factors Sp1 and NF-1. In contrast, the OCT2 promoter is not associated with a CpG island, contains a putative TATA box, and potential binding sites for specific transcription factors, such as HFH-8 and IK2. Since EMT and OCT2 may play important roles in catecholamine homeostasis and, as such, are candidate genes in human disease, the present results provide a basis for the analysis of genetic variation and the regulation of transcription.
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PMID:Gene structures of the human non-neuronal monoamine transporters EMT and OCT2. 1094 11

Pre-eclampsia is one of the most common causes of perinatal and maternal morbidity and mortality. High blood pressure and proteinuria are important clinical signs of pre-eclampsia. Sympathetic overactivity and elevated level of circulating vaso active substances, such as monoamines has been shown. Extracellular concentrations of monoamines are normally kept low by specific transporter proteins of which many are expressed in the placenta. In this study we used in situ hybridization and real-time PCR to study the gene expression of monoamine transporters, such as NET, SERT, VMAT2, EMT and OCT1/2, in normal as well as in pre-eclamptic placentae. We demonstrated high expression of NET mRNA in the trophoblast cells of the anchoring villi and a lower expression intensity in the chorionic villi. SERT mRNA was mainly detected in chorionic villi. VMAT2 mRNA was not detected in the central part of the placenta but was present in the spiral arteries of placenta bed biopsies, in cytokeratin positive cells. EMT mRNA was mainly detected in the intra lobular septa and together with OCT1 and OCT2 mRNAs also expressed in scattered cells of placental vessel adventitias. Moreover, quantitative analysis showed a significant lower expression of NET and EMT mRNAs in pre-eclamptic placentae as compared to the control group. A defective gene expression or function of these monoamines transporters might explain the elevated concentrations of monoamines in pre-eclamptic patients. Monoamine transporters may serve as a protective mechanism preventing vasoconstriction in the placental vascular bed and thereby securing a stable blood flow to the fetus.
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PMID:Norepinephrine transporter (NET), serotonin transporter (SERT), vesicular monoamine transporter (VMAT2) and organic cation transporters (OCT1, 2 and EMT) in human placenta from pre-eclamptic and normotensive pregnancies. 1513 35

The non-neuronal monoamine transporters OCT1, OCT2 and EMT (human gene symbols SLC22A1-A3) efficiently transport a number of positively-charged monoamines and some small organic cations across the plasma membrane, and thus are implicated in the inactivation of released monoamine transmitters (e.g. noradrenaline, histamine, agmatine) in vivo. Although prostaglandins are full anions at physiological pH, data from a recent publication suggest efficient transport of the prostaglandins PGE2 and PGF2alpha by OCT1 and OCT2. In the present study we have reexamined transport of PGE2 by OCT2 from human (OCT2h). Uptake of substrate into monolayers of 293 cells, stably transfected to express OCT2h, was compared to uptake into non-transfected control cells. Efficiency of transport of the established substrate 3H-1-methyl-4-phenylpyridinium (MPP+), expressed as clearance, was high at 81 microl min(-1) mg protein(-1) on average. By contrast, uptake of 3H-PGE2 was virtually identical for control cells and OCT2h cells. The efficiency of transport was 0.1+/-0.6, 1.0+/-0.3, and 0.7+/-0.4 microl min(-1) mg protein(-1) for cell lysis with methanol, HClO4, and Triton X-100 respectively. Similar results were obtained with unlabeled MPP+ (192+/-12 microl min(-1) mg protein(-1)) and PGE2 (0.3+/-0.1 microl min(-1) mg protein(-1)) in LC-MS/MS analysis. We conclude that OCT2h is not capable of transporting prostaglandins. The data from the previous report may represent binding rather than transport. Our comparison of transport efficiencies confirms the notion that relevant substrates of OCT1, OCT2, and EMT must carry a positive charge.
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PMID:Are organic cation transporters capable of transporting prostaglandins? 1621 6

For imaging of neuroblastoma and phaeochromocytoma, [(123)I]meta-iodobenzylguanidine ([(123)I]mIBG) is routinely used, whereas [(18)F]6-fluorodopamine ([(18)F]6-FDA) is sporadically applied for positron emission tomography in pheochromocytoma. Both substances are taken up by catecholamine transporters (CATs). In competition, some other cell types are able to take up catecholamines and related compounds probably by organic cation (OCT) [extraneuronal monoamine (EMT)] transporters (OCT1, OCT2, OCT3=EMT). In this study, we investigated the uptake of radioiodine-labeled meta-iodobenzylguanidine (mIBG) as well as [(3)H]dopamine (mimicring 6-fluorodopamine) and [(3)H]noradrenaline. SK-N-SH (neuroblastoma) and PC-12 (phaeochromocytoma) cells were used and compared with HEK-293 cells transfected with OCT1, OCT2 and OCT3, respectively. In order to gain a more selective uptake in CAT expressing tumor cells, different specific inhibitors were measured. Uptake of mIBG into OCT-expressing cells was similar or even better as into both CAT-expressing cell lines, whereas dopamine and noradrenaline uptake was much lower in OCT-expressing cells. In presence of corticosterone (f.c. 10(-4) M], catecholamine and mIBG uptake into SK-N-SH and PC-12 cells was only slightly reduced. In contrast, this process was significantly inhibited in OCT2 and OCT3 transfected HEK-293 as well as in Caki-1 cells, which naturally express OCT3. We conclude that the well-known corticosteroid corticosterone might be used in combination with [(18)F]6-FDA or [(123)I]mIBG to improve specific imaging of neuroblastoma and pheochromocytoma and to reduce irradiation dose to nontarget organs in [(131)I]mIBG treatment.
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PMID:Uptake of mIBG and catecholamines in noradrenaline- and organic cation transporter-expressing cells: potential use of corticosterone for a preferred uptake in neuroblastoma- and pheochromocytoma cells. 1932 74