A catecholamine transporter from the human parasite Schistosoma mansoni with low affinity for psychostimulants.
The trematode Schistosoma mansoni is the primary cause of schistosomiasis, a devastating neglected tropical disease that affects 200 million individuals. Identifying novel therapeutic targets for the treatment of schistosomiasis is therefore of great public interest. The catecholamines norepinephrine (NE) and dopamine (DA) are essential for the survival of the parasite as they cause muscular relaxation and a lengthening in the parasite and thereby control movement. Here we characterize a novel dopamine/norepinephrine transporter (SmDAT) gene transcript, from S. mansoni. The SmDAT is expressed in the adult form and in the sporocyst form (infected snails) of the parasite, and also in the egg and miracidium stage. It is absent in the cercariae stage but curiously a transcript missing the exon encoding transmembrane domain 8 was identified in this stage. Heterologous expression of the cDNA in mammalian cells resulted in saturable, dopamine transport activity with an apparent affinity for dopamine comparable to that of the human dopamine transporter. Efflux experiments reveal notably higher substrate selectivity compared with its mammalian counterparts as amphetamine is a much less potent efflux elicitor against SmDAT compared to the human DAT. Pharmacological characterization of the SmDAT revealed that most human DAT inhibitors including psychostimulants such as cocaine were significantly less potent in inhibiting SmDAT. Like DATs from other simpler organisms the pharmacology for SmDAT was more similar to the human norepinephrine transporter. We were not able to identify other dopamine transporting carriers within the completed parasite genome and we hypothesize that the SmDAT is the only catecholamine transporter in the parasite and could be responsible for not only clearing DA but also NE.
Department of Neurobiology, University of Pittsburgh School of Medicine, PA 15260, USA.
Mads B
MB
Larsen
Andréia C K
AC
Fontana
Lizandra G
LG
Magalhães
Vanderlei
V
Rodrigues
Ole V
OV
Mortensen
D000595:Amino Acid Sequence; D000818:Animals; D001337:Autonomic Agents / Q000737:chemistry / Q000378:metabolism*; D050482:Catecholamine Plasma Membrane Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002395:Catecholamines / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D018507:Gene Expression Regulation, Developmental; D015801:Helminth Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012550:Schistosoma mansoni / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D012555:Schistosomiasis mansoni; D012908:Snails / Q000469:parasitology; D013379:Substrate Specificity
D001337:Autonomic Agents; D050482:Catecholamine Plasma Membrane Transport Proteins; D002395:Catecholamines; D015801:Helminth Proteins
Traffic. 2008 Sep;9(9):1393-402
18445122
J Pharmacol Exp Ther. 1974 Aug;190(2):260-71
4155765
Mol Pharmacol. 2001 Jan;59(1):83-95
11125028
PLoS Biol. 2004 Mar;2(3):E78
15024426
J Neurochem. 1998 Oct;71(4):1369-80
9751167
J Biol Chem. 2006 Jan 27;281(4):2012-23
16272152
J Neurochem. 2008 Nov;107(4):928-40
18786172
Mol Biochem Parasitol. 2009 Nov;168(1):24-33
19545592
J Biol Chem. 2001 Feb 9;276(6):3805-10
11071889
Comp Biochem Physiol C Comp Pharmacol. 1977;58(2C):157-9
23928
Exp Parasitol. 1984 Dec;58(3):314-24
6500002
Mol Pharmacol. 2008 Mar;73(3):813-23
17978168
J Biol Chem. 2004 Oct 1;279(40):42147-56
15271993
J Neurochem. 2004 May;89(4):853-64
15140185
N Engl J Med. 2002 Apr 18;346(16):1212-20
11961151
J Neurochem. 2006 Sep;98(5):1531-40
16923164
J Exp Biol. 2006 Dec;209(Pt 24):4858-68
17142674
Parasitology. 1993 Sep;107 ( Pt 3):265-74
8233590
Curr Opin Infect Dis. 2008 Dec;21(6):659-67
18978535
Nat Neurosci. 2008 Jul;11(7):780-9
18568020
Mol Genet Genomics. 2002 Mar;267(1):96-106
11919720
Am J Trop Med Hyg. 1983 Jan;32(1):83-93
6130710
Eur J Pharmacol. 2003 Oct 31;479(1-3):159-70
14612147
Nat Rev Neurosci. 2003 Jan;4(1):13-25
12511858
Lancet. 2006 Sep 23;368(9541):1106-18
16997665
Eur J Pharmacol. 2009 Aug 15;616(1-3):48-57
19549517
Proc Natl Acad Sci U S A. 1994 Jun 7;91(12):5355-8
8202492
PLoS One. 2010 Aug 05;5(8):e11945
20700532
J Neurochem. 2005 Jul;94(2):352-9
15998286
J Pharmacol Exp Ther. 2005 Aug;314(2):575-83
15879005
Mol Biol Cell. 2008 Jul;19(7):2818-29
18434601