title: Genetic variants and increased expression of Parascaris equorum P-glycoprotein-11 in populations with decreased ivermectin susceptibility.
abstract: Macrocyclic lactones (MLs) represent the major drug class for control of parasitic infections in humans and animals. However, recently reports of treatment failures became more frequent. In addition to human and ruminant parasitic nematodes this also is the case for the horse-nematode Parascaris equorum. Nevertheless, to date the molecular basis of ML resistance is still not understood. Unspecific resistance mechanisms involving transporters such as P-glycoproteins (Pgps) are expected to contribute to ML resistance in nematodes. Here, complete sequences of two P. equorum Pgps were cloned and identified as orthologs of Caenorhabditis elegans Ppg-11 and an unnamed Caenorhabditis briggsae Pgp designated as Pgp-16 using phylogenetic analysis. Quantitative real-time PCR was used to compare expression between tissues. Significantly higher PeqPgp-11 expression was found in the gut for both genders, whereas for PeqPgp-16 the body wall was identified as predominant expression site. Furthermore, Pgps were analyzed regarding their participation in resistance development. Using SeqDoC analyses, Pgp-sequences of P. equorum populations with different ML susceptibility were compared. This approach revealed three single nucleotide polymorphisms (SNPs) causing missense mutations in the PeqPgp-11 sequence which correlated with decreased ML susceptibility. However, no resistance associated differences in mRNA expression levels were detected between embryonated eggs of these populations. In contrast, comparison of two pre-adult groups with different ivermectin (IVM) susceptibility revealed the presence of the three SNPs and in addition statistically significant PeqPgp-11 overexpression in the group of worms with reduced susceptibility. These results indicate that Pgp-11 might be involved in IVM resistance in P. equorum as it shows increased expression in an IVM exposed life-cycle stage of an IVM resistant population as well as occurrence of putatively resistance associated SNPs in populations with reduced IVM susceptibility. These SNPs are promising diagnostic candidates for detection of ML resistance with potential also for other parasitic nematode species.
authors: Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Germany.
authors: I Jana I
authors: IJ
authors: Janssen
authors: Jürgen
authors: J
authors: Krücken
authors: Janina
authors: J
authors: Demeler
authors: Marta
authors: M
authors: Basiaga
authors: Sławomir
authors: S
authors: Kornaś
authors: Georg
authors: G
authors: von Samson-Himmelstjerna
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics*; D000483:Alleles; D000818:Animals; D000969:Antinematodal Agents / Q000494:pharmacology*; D001199:Ascaridoidea / Q000145:classification / Q000187:drug effects* / Q000235:genetics*; D004351:Drug Resistance / Q000235:genetics; D005260:Female; D015870:Gene Expression; D005786:Gene Expression Regulation / Q000187:drug effects; D005787:Gene Frequency; D014644:Genetic Variation; D006736:Horses / Q000469:parasitology; D007559:Ivermectin / Q000494:pharmacology*; D008297:Male; D009928:Organ Specificity / Q000235:genetics; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D000969:Antinematodal Agents; D012333:RNA, Messenger; D007559:Ivermectin
references: J Parasitol. 1994 Jun;80(3):493-7
references: 8195956
references: Genome Biol. 2007;8(2):R19
references: 17291332
references: Parasit Vectors. 2009 Sep 25;2 Suppl 2:S8
references: 19778469
references: N Z Vet J. 2006 Dec;54(6):323-8
references: 17151732
references: Vet Parasitol. 2012 Dec 21;190(3-4):519-29
references: 22840641
references: EMBO J. 1996 Nov 15;15(22):6132-43
references: 8947035
references: Parasitol Today. 1999 Apr;15(4):141-6
references: 10322335
references: Clin Chem. 2009 Apr;55(4):611-22
references: 19246619
references: Curr Pharm Biotechnol. 2012 May;13(6):853-65
references: 22039784
references: Bioinformatics. 2002 Sep;18(9):1250-6
references: 12217917
references: PLoS Negl Trop Dis. 2011 Mar 29;5(3):e998
references: 21468315
references: Exp Parasitol. 1999 Mar;91(3):250-7
references: 10072327
references: BMC Bioinformatics. 2005 May 31;6:133
references: 15927052
references: Biochem Pharmacol. 2012 Jan 15;83(2):269-78
references: 22024132
references: Mol Biochem Parasitol. 1999 Aug 20;102(2):273-81
references: 10498183
references: Vet Parasitol. 2011 Mar 22;176(4):374-81
references: 21300438
references: Mol Biochem Parasitol. 2011 Dec;180(2):99-105
references: 21945142
references: Mol Biol Evol. 2008 Jul;25(7):1307-20
references: 18367465
references: Vet Parasitol. 2008 Mar 25;152(1-2):101-7
references: 18241994
references: Int J Parasitol. 2011 Aug 1;41(9):935-42
references: 21683705
references: Vet Parasitol. 2011 Sep 27;181(2-4):388-92
references: 21570194
references: J Neurochem. 2004 Jun;89(5):1137-47
references: 15147506
references: Cell. 1987 Jun 19;49(6):753-61
references: 3581169
references: Mol Biochem Parasitol. 2005 Sep;143(1):58-66
references: 15993957
references: Syst Biol. 2011 Oct;60(5):685-99
references: 21540409
references: Bioinformatics. 2005 May 1;21(9):2104-5
references: 15647292
references: Trends Parasitol. 2010 Jul;26(7):334-40
references: 20478743
references: Vet Parasitol. 2010 Nov 24;174(1-2):77-84
references: 20850927
references: J Helminthol. 2012 Jun;86(2):202-8
references: 21729384
references: Mol Biochem Parasitol. 1998 Mar 15;91(2):327-35
references: 9566525
references: Parasit Vectors. 2009 Sep 25;2 Suppl 2:S3
references: 19778464
references: Trends Parasitol. 2004 Oct;20(10):469-76
references: 15363440
references: PLoS Negl Trop Dis. 2009;3(3):e397
references: 19308251
references: Int J Parasitol. 1979 Aug;9(4):285-92
references: 489235
references: EMBO J. 1995 May 1;14(9):1858-66
references: 7743993
references: Science. 2009 Mar 27;323(5922):1718-22
references: 19325113
references: Int J Antimicrob Agents. 2003 Sep;22(3):332-46
references: 13678840
references: Parasitology. 2010 Jul;137(8):1195-212
references: 20233492
references: Science. 1974 Sep 6;185(4154):862-4
references: 4843792
references: Bioinformatics. 2011 Apr 15;27(8):1164-5
references: 21335321
references: Parasitology. 2007;134(Pt 8):1123-32
references: 17608972
references: Parasitology. 2009 Mar;136(3):349-58
references: 19154653
references: Int J Parasitol Drugs Drug Resist. 2011 Nov 07;2:58-75
references: 24533264
references: Mol Biochem Parasitol. 1998 Sep 15;95(2):193-201
references: 9803412
references: J Mol Biol. 1992 Nov 20;228(2):701-11
references: 1360540
references: Vet Parasitol. 2012 Apr 19;185(1):9-15
references: 22078748
references: PLoS Negl Trop Dis. 2007 Aug 30;1(1):e76
references: 17989789
references: Parasitol Res. 2003 Sep;91(1):79-85
references: 12898231
references: Int J Parasitol. 2009 Jan;39(2):213-20
references: 18708066
references: Parasitology. 2000 May;120 ( Pt 5):535-45
references: 10840983
references: J Parasitol. 2004 Oct;90(5):998-1003
references: 15562598
references: Parasitology. 2011 Feb;138(2):160-74
references: 20825689
references: Int J Parasitol. 1998 Aug;28(8):1235-40
references: 9762570
references: J Mol Biol. 2004 Nov 19;344(2):409-17
references: 15522294
references: Syst Biol. 2010 May;59(3):307-21
references: 20525638
references: Cell. 1999 Jan 8;96(1):47-56
references: 9989496