Dataset Information

Comparative proteomics of three Giardia lamblia strains: Antigenic variation in the post-genomic era

ABSTRACT: Giardia lamblia is a causative agent of persistent diarrhea widespread in regions with low hygienic standards. Laboratory research is based on cloned lines issuing from various patient isolates typed in the late 1980s and 90s using restriction analysis and serology. In the present study, we compared the well characterized strain WBC6 with another clone of the parent WB isolate termed WBA1 and with a clone from another isolate, GS/M-83-H7, using shotgun mass spectrometry proteomics. We identified 398 proteins differentially expressed between the GS and both WB isolates and 97 proteins differentially expressed between both WB isolates. We investigated the expression levels of the predominant variant-specific surface proteins (VSPs) in each clone and matched the previously described major VSPs of each strain to the corresponding open reading frame (ORF) sequences identified by whole-genome sequencing efforts. Furthermore, since the original WB isolate comes from a patient treated with metronidazole, we compared the susceptibilities of the strains to nitro compounds, as well the expression levels of enzymes involved in nitro reduction and on the corresponding enzyme activities and found distinct differences between the three strains.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Giardia Intestinalis (giardia Lamblia)

TISSUE(S): Cell Culture

SUBMITTER: Manfred Heller

LAB HEAD: Loachim Müller

PROVIDER: PXD017597 | Pride | 2020-05-20

REPOSITORIES: Pride

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Dataset's files

Source:

			Action	DRS
	20190212_2_WBC6_JM_i01.raw	Raw
	20190212_2_WBC6_JM_i02.raw	Raw
	20190212_2_WBC6_JM_i03.raw	Raw
	20190212_6_A1_JM_i01.raw	Raw
	20190212_6_A1_JM_i02.raw	Raw

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Publications

Comparative proteomics of three <i>Giardia lamblia</i> strains: investigation of antigenic variation in the post-genomic era.

Müller Joachim J Braga Sophie S Uldry Anne-Christine AC Heller Manfred M Müller Norbert N

Parasitology 20200427 9

Giardia lamblia is a causative agent of persistent diarrhoea widespread in regions with low hygienic standards. Laboratory research is based on cloned lines issuing from various patient isolates typed in the late 1980s and 90s using restriction analysis and serology. In the present study, we compared the well-characterized strain WBC6 with another clone of the parent WB isolate termed WBA1 and with a clone from another isolate, GS/M-83-H7, using shotgun mass spectrometry proteomics. We identifie ...[more]

PMID: 32338227

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Project description:Giardia causes more episodes of illness worldwide than any other parasite. It is a flagellated cyst-forming enteric pathogen that inhabits the lumen of the small intestine and although it is clear that more and less virulent strains do occur, pathogenesis and virulence of Giardia remains poorly understood. Identification of Giardia virulence factors is highly desirable since their expression would be the best indicator for determining disease outcome. The advent of quantitative proteomics has been timely in investigating which proteins are likely to be secreted virulence factors. Here we successfully apply such analyses to the whole parasite and to the supernatants derived from the parasite, in order to ascertain a repertoire of secreted proteins. In our initial analysis we compared replicates of Giardia cells and culture supernatants from the two major lineages which cause human disease – assemblage A and assemblage B. The genome of Giardia is believed to contain open reading frames which could encode as many as 6000 proteins. In our study we confirm expression of ~1600 proteins from each assemblage, the vast majority of which being common to both lineages. To look for actual enrichment of secreted proteins, we considered the ratio of proteins in the supernatant compared with the pellet. This simple method defines a small group of enriched proteins, putatively secreted at a steady state by cultured growing Giardia trophozoites of both assemblages. This secretome contains a high proportion annotated to have N’ terminus signal peptides, with some showing evidence of having recently evolved under strong positive selective pressure. The most abundant secreted proteins include known virulence factors such as the Cathepsin B cysteine proteases and members of a Giardia superfamily of Cysteine Rich Proteins which comprises VSPs, HCMPs and a new class of virulence factors, the Giardia Tenascins. Since we also find that physiological function of human enteric epithelial cells can be disrupted by soluble factors even in the absence of the trophozoites we are able to propose a straightforward model of Giardia pathogenesis incorporating key roles for the major Giardia derived soluble mediators.

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