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. 2017 Dec 27;13(12):e1006800.
doi: 10.1371/journal.ppat.1006800. eCollection 2017 Dec.

Host triacylglycerols shape the lipidome of intracellular trypanosomes and modulate their growth

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Host triacylglycerols shape the lipidome of intracellular trypanosomes and modulate their growth

Felipe Gazos-Lopes et al. PLoS Pathog. .

Abstract

Intracellular infection and multi-organ colonization by the protozoan parasite, Trypanosoma cruzi, underlie the complex etiology of human Chagas disease. While T. cruzi can establish cytosolic residence in a broad range of mammalian cell types, the molecular mechanisms governing this process remain poorly understood. Despite the anticipated capacity for fatty acid synthesis in this parasite, recent observations suggest that intracellular T. cruzi amastigotes may rely on host fatty acid metabolism to support infection. To investigate this prediction, it was necessary to establish baseline lipidome information for the mammalian-infective stages of T. cruzi and their mammalian host cells. An unbiased, quantitative mass spectrometric analysis of lipid fractions was performed with the identification of 1079 lipids within 30 classes. From these profiles we deduced that T. cruzi amastigotes maintain an overall lipid identity that is distinguishable from mammalian host cells. A deeper analysis of the fatty acid moiety distributions within each lipid subclass facilitated the high confidence assignment of host- and parasite-like lipid signatures. This analysis unexpectedly revealed a strong host lipid signature in the parasite lipidome, most notably within its glycerolipid fraction. The near complete overlap of fatty acid moiety distributions observed for host and parasite triacylglycerols suggested that T. cruzi amastigotes acquired a significant portion of their lipidome from host triacylglycerol pools. Metabolic tracer studies confirmed long-chain fatty acid scavenging by intracellular T. cruzi amastigotes, a capacity that was significantly diminished in host cells deficient for de novo triacylglycerol synthesis via the diacylglycerol acyltransferases (DGAT1/2). Reduced T. cruzi amastigote proliferation in DGAT1/2-deficient fibroblasts further underscored the importance of parasite coupling to host triacylglycerol pools during the intracellular infection cycle. Thus, our comprehensive lipidomic dataset provides a substantially enhanced view of T. cruzi infection biology highlighting the interplay between host and parasite lipid metabolism with potential bearing on future therapeutic intervention strategies.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Overview of experimental design, evaluation of T. cruzi amastigote isolation and LC-MS/MS methods.
(A) Schematic overview of the experimental approach that involved parallel lipidomics analysis of T. cruzi parasites isolated from two different mammalian cell types: C2C12 (mouse skeletal myoblast) and HFF (human foreskin fibroblasts). Host cell infection was established with T. cruzi trypomastigotes (TCT) and intracellular T. cruzi amastigotes (ICA) were isolated from infected host cells 48 hours post infection as detailed in the Methods. T. cruzi amastigote purity was evaluated using (B) transmission electron microscopy, scale bar = 2 μm, and (C) western blot analysis using antibodies to T. cruzi, host mitochondria (ATP5B), endoplasmic reticulum (IRE1) and lipid droplets (TIP47) to probe whole cell lysates of control uninfected HFF (HFFu), T. cruzi-infected HFF (HFFi), and T. cruzi amastigotes purified from HFF (hICA). (D) Positive ion mode base peak chromatogram of lipid extracts derived from C2C12, HFF, and cognate T. cruzi amastigote (cICA and hICA, respectively) analyzed by LC-ESI-MS/MS. The major lipid subclasses eluting at different retention times (min) are indicated above the chromatogram. TG–triacylglycerol, DG–diacylglycerol, Cer–ceramide, CerG–hexosylceramide, SM–sphingomyelin, LPC–lysophosphatidylcholine, PC–phosphatidylcholine, LPE–lysophosphatidylethanolamine, PE–phosphatidylethanolamine, LPS–lysophosphatidylserine, PS–phosphatidylserine, PI–phosphatidylinositol, PG–phosphatidylglycerol.
Fig 2
Fig 2. Lipid class breakdown in T. cruzi and mammalian cells.
Pie charts display the relative abundance of the major lipid subclasses of mammalian host cells (C2C12 and HFF) and T. cruzi intracellular amastigotes (ICA) and tissue-culture trypomastigotes (TCT) represented as a portion of total lipid content in each sample, averaged for 4 independent experiments. TG–triacylglycerol, DG–diacylglycerol, Cer–ceramide, CerG–hexosylceramide, SM–sphingomyelin, PC–phosphatidylcholine, PE–phosphatidylethanolamine, PS–phosphatidylserine, PI–phosphatidylinositol, PG–phosphatidylglycerol.
Fig 3
Fig 3. Principle component analysis of host and parasite lipidomes at the lipid species level.
Principle component analysis of lipid species are plotted for the (A) total lipidome, (B) TG subclass, and (C) PI subclass. The first two principle components are plotted (PC1 and PC2) with proportion of variance for each component shown in parenthesis. Each sample is represented and the 95% confidence interval indicated in shaded circle.
Fig 4
Fig 4. Trends in host and parasite FA composition varies between lipid classes.
The relative proportion of identified FA for (A) PE, (B) PI, (C) PC, and (D) LPC lipid subclasses is plotted (FA area %; calculated as detailed in Methods) for HFF-derived samples (C2C12-derived samples plotted in S4 Fig): uninfected HFF (HFFu), T. cruzi-infected HFF (HFFi) and T. cruzi amastigotes purified from HFF (hICA). The long-chain fatty acid (LCFA) and very long-chain polyunsaturated fatty acid (VLC-PUFA) are plotted separately for clarity. Data are represented as mean ± standard deviation.
Fig 5
Fig 5. FA composition in TG and DG of T. cruzi intracellular amastigotes mirrors host cells.
FA area % is plotted for (A) TG and (B) DG classes for HFF-derived samples, (C2C12 plotted in S5 Fig): uninfected HFF (HFFu), T. cruzi-infected HFF (HFFi) and T. cruzi amastigotes purified from HFF (hICA). Data are represented as mean ± standard deviation.
Fig 6
Fig 6. T. cruzi intracellular amastigotes (ICA) scavenge and incorporate exogenous FA, amastigote FA acquisition and proliferation are compromised in DGAT-TG synthesis deficient host cells.
Lipidomic analysis of uninfected HFF (uninfected), T. cruzi-infected HFF (infected) and T. cruzi amastigotes purified from HFF (ICA) show incorporation of exogenous C15:0 FA into (A) TG, (A, inset) total FA, dotted line indicates the average C15:0, C17:0, C17:1 in unlabeled samples, (B) PI, and (C) PE. Representative autoradiographs showing (D) neutral lipid and (E) glycerophospholipid TLC analysis of 14C-palmitate incorporation into uninfected (lanes 1–3), infected (lanes 4–6), and isolated amastigotes (lanes 7–9) from wild type mouse embryonic fibroblasts, diacylglycerol acyl transferase 1/2 knockout MEF DGAT1/2-/-, and DGAT1/2-/- (+DGAT2) cell lines, respectively; (F) Proliferation of T. cruzi amastigotes measured by CFSE intensity at 18 hpi (undivided) and 48 hpi in WT MEF, DGAT1/2-/- and DGAT1/2-/- (+DGAT2) cell lines.

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References

    1. Nunes MC, Guimaraes MH Junior, Diamantino AC, Gelape CL, Ferrari TC. Cardiac manifestations of parasitic diseases. Heart. 2017; 103(9):651–8. doi: 10.1136/heartjnl-2016-309870 . - DOI - PubMed
    1. World Health Organization WHO. Chagas Disease (American Trypanosomiasis) 2017 [29 Mar 2017]. http://www.who.int/mediacentre/factsheets/fs340/en/.
    1. Pecoul B, Batista C, Stobbaerts E, Ribeiro I, Vilasanjuan R, Gascon J, et al. The BENEFIT Trial: Where Do We Go from Here? PLoS Negl Trop Dis. 2016;10(2):e0004343 doi: 10.1371/journal.pntd.0004343 . - DOI - PMC - PubMed
    1. Lee BY, Bacon KM, Bottazzi ME, Hotez PJ. Global economic burden of Chagas disease: a computational simulation model. Lancet Infect Dis. 2013;13(4):342–8. doi: 10.1016/S1473-3099(13)70002-1 . - DOI - PMC - PubMed
    1. Prata A. Clinical and epidemiological aspects of Chagas disease. Lancet Infect Dis. 2001;1(2):92–100. doi: 10.1016/S1473-3099(01)00065-2 . - DOI - PubMed

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