title: Identification of differentially expressed proteins in sulfadiazine resistant and sensitive strains of Toxoplasma gondii using difference-gel electrophoresis (DIGE).
abstract: Treatment options for toxoplasmosis in humans are generally limited to the use of sulfonamide and/or pyrimethamine-based compounds. However, there is increasing evidence for clinical therapy failures in patients suggesting the existence of drug resistance in these classes of drug. In vitro resistance to sulfadiazine has been detected in three strains of Toxoplasma gondii isolated from clinical cases. In order to begin to understand the mechanisms of resistance, we undertook a difference-gel electrophoresis (DIGE) approach combined with mass spectrometry to identify proteins that are differentially expressed in sulfadiazine-resistance strains of the parasite. Naturally resistant strains TgA 103001 (Type I), TgH 32006 (Type II) and TgH 32045 (Type II variant) were compared to sensitive strains RH (Type I) and ME-49 (Type II) using DIGE and the modulated proteins analyzed using LC-MS/MS. In total, 68 differentially expressed protein spots were analyzed by mass spectrometer and 31 unique proteins, including four hypothetical proteins, were identified. Among the differentially expressed proteins, 44% were over-expressed in resistant strains and 56% were over-expressed in sensitive strains. The virulence-associated rhoptry protein, ROP2A, was found in greater abundance in both naturally resistant Type II strains TgH 32006 and TgH 32045 compared to the sensitive strain ME-49. Enolase 2 and IMC1 were found to be in greater abundance in sensitive strains RH and ME-49, and MIC2 was found to be more abundant in the sensitive strain ME-49. Proteins regulation of ROP2, MIC2, ENO2, IMC1 and GRA7 were confirmed by Western blot analysis. In addition, gene expression patterns of ROP2, MIC2, ENO2 and IMC1 were analyzed with qRT-PCR. This study provides the first proteomics insights into sulfadiazine resistance in T. gondii resistant strains isolated from clinical cases.
authors.affiliation: Protozooses, transmises par l'alimentation: circulation et pathogénie, EA 3800, SFR CAP-Santé FED 4231, Université de Reims Champagne-Ardenne, 51 rue Cognacq-Jay, 51095 Reims Cedex, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Doliwa
authors.affiliation: Institute of Infection & Global Health, Faculty of Health and Life Sciences, University of Liverpool, Brownlow Hill, Liverpool L69 7ZJ, United Kingdom.
authors.forename: Dong
authors.initials: D
authors.lastname: Xia
authors.affiliation: Protozooses, transmises par l'alimentation: circulation et pathogénie, EA 3800, SFR CAP-Santé FED 4231, Université de Reims Champagne-Ardenne, 51 rue Cognacq-Jay, 51095 Reims Cedex, France ; BRC Toxoplasma and NRC on Toxoplasmosis, Hôpital Maison Blanche, 45 rue Cognacq-Jay, 51092 Reims Cedex, France.
authors.forename: Sandie
authors.initials: S
authors.lastname: Escotte-Binet
authors.affiliation: Institute of Infection & Global Health, Faculty of Health and Life Sciences, University of Liverpool, Brownlow Hill, Liverpool L69 7ZJ, United Kingdom.
authors.forename: Emma L
authors.initials: EL
authors.lastname: Newsham
authors.affiliation: Institute of Infection & Global Health, Faculty of Health and Life Sciences, University of Liverpool, Brownlow Hill, Liverpool L69 7ZJ, United Kingdom.
authors.forename: Sanderson
authors.initials: S
authors.lastname: Sanya J
authors.affiliation: Protozooses, transmises par l'alimentation: circulation et pathogénie, EA 3800, SFR CAP-Santé FED 4231, Université de Reims Champagne-Ardenne, 51 rue Cognacq-Jay, 51095 Reims Cedex, France ; BRC Toxoplasma and NRC on Toxoplasmosis, Hôpital Maison Blanche, 45 rue Cognacq-Jay, 51092 Reims Cedex, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Aubert
authors.affiliation: Institute of Infection & Global Health, Faculty of Health and Life Sciences, University of Liverpool, Brownlow Hill, Liverpool L69 7ZJ, United Kingdom.
authors.forename: Nadine
authors.initials: N
authors.lastname: Randle
authors.affiliation: Institute of Infection & Global Health, Faculty of Health and Life Sciences, University of Liverpool, Brownlow Hill, Liverpool L69 7ZJ, United Kingdom.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Wastling
authors.affiliation: Protozooses, transmises par l'alimentation: circulation et pathogénie, EA 3800, SFR CAP-Santé FED 4231, Université de Reims Champagne-Ardenne, 51 rue Cognacq-Jay, 51095 Reims Cedex, France ; BRC Toxoplasma and NRC on Toxoplasmosis, Hôpital Maison Blanche, 45 rue Cognacq-Jay, 51092 Reims Cedex, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Villena
keywords: DIGE; Drug resistance; EF1-α, elongation factor 1 alpha; ENO2, enolase 2; G3PDH, glyceraldehyde-3-phosphate dehydrogenase; GRA2, dense granule protein 2; GRA7, dense granule protein 7; Hsp70, heat shock protein 70; Hsp90, heat shock protein 90; MIC1, microneme protein 1; MIC2, microneme protein 2; PP2C, protein phosphatase 2C; ROP2, rhoptry protein 2; ROP9, rhoptry protein 9; Sulfadiazine; TgCDPK1, Toxoplasma gondii calcium-dependent protein kinase 1; Toxoplasma gondii; eIF-5A, translation initiation factor 5A; small Hsp20, small heat shock protein 20