Independent origins of loss-of-function mutations conferring oxamniquine resistance in a Brazilian schistosome population

Frédéric D. Chevalier, Winka Le Clec'h, Nina Eng, Anastasia R. Rugel, Rafael Ramiro de Assis, Guilherme Oliveira, Stephen P. Holloway, Xiaohang Cao, P. John Hart, Philip T Loverde, Timothy J C Anderson

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Molecular surveillance provides a powerful approach to monitoring the resistance status of parasite populations in the field and for understanding resistance evolution. Oxamniquine was used to treat Brazilian schistosomiasis patients (mid-1970s to mid-2000s) and several cases of parasite infections resistant to treatment were recorded. The gene underlying resistance (SmSULT-OR) encodes a sulfotransferase required for intracellular drug activation. Resistance has a recessive basis and occurs when both . SmSULT-OR alleles encode for defective proteins. Here we examine . SmSULT-OR sequence variation in a natural schistosome population in Brazil ∼40. years after the first use of this drug. We sequenced . SmSULT-OR from 189 individual miracidia (1-11 per patient) recovered from 49 patients, and tested proteins expressed from putative resistance alleles for their ability to activate oxamniquine. We found nine mutations (four non-synonymous single nucleotide polymorphisms, three non-coding single nucleotide polymorphisms and two indels). Both mutations (p.E142del and p.C35R) identified previously were recovered in this field population. We also found two additional mutations (a splice site variant and 1. bp coding insertion) predicted to encode non-functional truncated proteins. Two additional substitutions (p.G206V, p.N215Y) tested had no impact on oxamniquine activation. Three results are of particular interest: (i) we recovered the p.E142del mutation from the field: this same deletion is responsible for resistance in an oxamniquine selected laboratory parasite population; (ii) frequencies of resistance alleles are extremely low (0.27-0.8%), perhaps due to fitness costs associated with carriage of these alleles; (iii) that four independent resistant alleles were found is consistent with the idea that multiple mutations can generate loss-of-function alleles.

Original languageEnglish (US)
JournalInternational Journal for Parasitology
DOIs
StateAccepted/In press - Dec 1 2015

Fingerprint

Oxamniquine
Alleles
Mutation
Population
Single Nucleotide Polymorphism
Parasites
Sulfotransferases
Parasitic Diseases
Proteins
Schistosomiasis
Gene Frequency
Brazil
Costs and Cost Analysis
Pharmaceutical Preparations
Genes

Keywords

  • Biochemical assay
  • Loss-of-function
  • Oxamniquine resistance
  • Schistosoma mansoni
  • Soft selective event
  • Sulfotransferase

ASJC Scopus subject areas

  • Parasitology
  • Infectious Diseases

Cite this

Independent origins of loss-of-function mutations conferring oxamniquine resistance in a Brazilian schistosome population. / Chevalier, Frédéric D.; Le Clec'h, Winka; Eng, Nina; Rugel, Anastasia R.; Assis, Rafael Ramiro de; Oliveira, Guilherme; Holloway, Stephen P.; Cao, Xiaohang; Hart, P. John; Loverde, Philip T; Anderson, Timothy J C.

In: International Journal for Parasitology, 01.12.2015.

Research output: Contribution to journalArticle

Chevalier, Frédéric D. ; Le Clec'h, Winka ; Eng, Nina ; Rugel, Anastasia R. ; Assis, Rafael Ramiro de ; Oliveira, Guilherme ; Holloway, Stephen P. ; Cao, Xiaohang ; Hart, P. John ; Loverde, Philip T ; Anderson, Timothy J C. / Independent origins of loss-of-function mutations conferring oxamniquine resistance in a Brazilian schistosome population. In: International Journal for Parasitology. 2015.
@article{2d52e70c8f2746868320b765c75b509c,
title = "Independent origins of loss-of-function mutations conferring oxamniquine resistance in a Brazilian schistosome population",
abstract = "Molecular surveillance provides a powerful approach to monitoring the resistance status of parasite populations in the field and for understanding resistance evolution. Oxamniquine was used to treat Brazilian schistosomiasis patients (mid-1970s to mid-2000s) and several cases of parasite infections resistant to treatment were recorded. The gene underlying resistance (SmSULT-OR) encodes a sulfotransferase required for intracellular drug activation. Resistance has a recessive basis and occurs when both . SmSULT-OR alleles encode for defective proteins. Here we examine . SmSULT-OR sequence variation in a natural schistosome population in Brazil ∼40. years after the first use of this drug. We sequenced . SmSULT-OR from 189 individual miracidia (1-11 per patient) recovered from 49 patients, and tested proteins expressed from putative resistance alleles for their ability to activate oxamniquine. We found nine mutations (four non-synonymous single nucleotide polymorphisms, three non-coding single nucleotide polymorphisms and two indels). Both mutations (p.E142del and p.C35R) identified previously were recovered in this field population. We also found two additional mutations (a splice site variant and 1. bp coding insertion) predicted to encode non-functional truncated proteins. Two additional substitutions (p.G206V, p.N215Y) tested had no impact on oxamniquine activation. Three results are of particular interest: (i) we recovered the p.E142del mutation from the field: this same deletion is responsible for resistance in an oxamniquine selected laboratory parasite population; (ii) frequencies of resistance alleles are extremely low (0.27-0.8{\%}), perhaps due to fitness costs associated with carriage of these alleles; (iii) that four independent resistant alleles were found is consistent with the idea that multiple mutations can generate loss-of-function alleles.",
keywords = "Biochemical assay, Loss-of-function, Oxamniquine resistance, Schistosoma mansoni, Soft selective event, Sulfotransferase",
author = "Chevalier, {Fr{\'e}d{\'e}ric D.} and {Le Clec'h}, Winka and Nina Eng and Rugel, {Anastasia R.} and Assis, {Rafael Ramiro de} and Guilherme Oliveira and Holloway, {Stephen P.} and Xiaohang Cao and Hart, {P. John} and Loverde, {Philip T} and Anderson, {Timothy J C}",
year = "2015",
month = "12",
day = "1",
doi = "10.1016/j.ijpara.2016.03.006",
language = "English (US)",
journal = "International Journal for Parasitology",
issn = "0020-7519",
publisher = "Elsevier Limited",

}

TY - JOUR

T1 - Independent origins of loss-of-function mutations conferring oxamniquine resistance in a Brazilian schistosome population

AU - Chevalier, Frédéric D.

AU - Le Clec'h, Winka

AU - Eng, Nina

AU - Rugel, Anastasia R.

AU - Assis, Rafael Ramiro de

AU - Oliveira, Guilherme

AU - Holloway, Stephen P.

AU - Cao, Xiaohang

AU - Hart, P. John

AU - Loverde, Philip T

AU - Anderson, Timothy J C

PY - 2015/12/1

Y1 - 2015/12/1

N2 - Molecular surveillance provides a powerful approach to monitoring the resistance status of parasite populations in the field and for understanding resistance evolution. Oxamniquine was used to treat Brazilian schistosomiasis patients (mid-1970s to mid-2000s) and several cases of parasite infections resistant to treatment were recorded. The gene underlying resistance (SmSULT-OR) encodes a sulfotransferase required for intracellular drug activation. Resistance has a recessive basis and occurs when both . SmSULT-OR alleles encode for defective proteins. Here we examine . SmSULT-OR sequence variation in a natural schistosome population in Brazil ∼40. years after the first use of this drug. We sequenced . SmSULT-OR from 189 individual miracidia (1-11 per patient) recovered from 49 patients, and tested proteins expressed from putative resistance alleles for their ability to activate oxamniquine. We found nine mutations (four non-synonymous single nucleotide polymorphisms, three non-coding single nucleotide polymorphisms and two indels). Both mutations (p.E142del and p.C35R) identified previously were recovered in this field population. We also found two additional mutations (a splice site variant and 1. bp coding insertion) predicted to encode non-functional truncated proteins. Two additional substitutions (p.G206V, p.N215Y) tested had no impact on oxamniquine activation. Three results are of particular interest: (i) we recovered the p.E142del mutation from the field: this same deletion is responsible for resistance in an oxamniquine selected laboratory parasite population; (ii) frequencies of resistance alleles are extremely low (0.27-0.8%), perhaps due to fitness costs associated with carriage of these alleles; (iii) that four independent resistant alleles were found is consistent with the idea that multiple mutations can generate loss-of-function alleles.

AB - Molecular surveillance provides a powerful approach to monitoring the resistance status of parasite populations in the field and for understanding resistance evolution. Oxamniquine was used to treat Brazilian schistosomiasis patients (mid-1970s to mid-2000s) and several cases of parasite infections resistant to treatment were recorded. The gene underlying resistance (SmSULT-OR) encodes a sulfotransferase required for intracellular drug activation. Resistance has a recessive basis and occurs when both . SmSULT-OR alleles encode for defective proteins. Here we examine . SmSULT-OR sequence variation in a natural schistosome population in Brazil ∼40. years after the first use of this drug. We sequenced . SmSULT-OR from 189 individual miracidia (1-11 per patient) recovered from 49 patients, and tested proteins expressed from putative resistance alleles for their ability to activate oxamniquine. We found nine mutations (four non-synonymous single nucleotide polymorphisms, three non-coding single nucleotide polymorphisms and two indels). Both mutations (p.E142del and p.C35R) identified previously were recovered in this field population. We also found two additional mutations (a splice site variant and 1. bp coding insertion) predicted to encode non-functional truncated proteins. Two additional substitutions (p.G206V, p.N215Y) tested had no impact on oxamniquine activation. Three results are of particular interest: (i) we recovered the p.E142del mutation from the field: this same deletion is responsible for resistance in an oxamniquine selected laboratory parasite population; (ii) frequencies of resistance alleles are extremely low (0.27-0.8%), perhaps due to fitness costs associated with carriage of these alleles; (iii) that four independent resistant alleles were found is consistent with the idea that multiple mutations can generate loss-of-function alleles.

KW - Biochemical assay

KW - Loss-of-function

KW - Oxamniquine resistance

KW - Schistosoma mansoni

KW - Soft selective event

KW - Sulfotransferase

UR - http://www.scopus.com/inward/record.url?scp=84964265141&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84964265141&partnerID=8YFLogxK

U2 - 10.1016/j.ijpara.2016.03.006

DO - 10.1016/j.ijpara.2016.03.006

M3 - Article

JO - International Journal for Parasitology

JF - International Journal for Parasitology

SN - 0020-7519

ER -