Metabolomic profiling reveals a finely tuned, starvation-induced metabolic switch in Trypanosoma cruzi epimastigotes

Abstract

Edited by Chris WhitfieldTrypanosoma cruzi, the etiological agent of Chagas disease, is a protozoan parasite with a complex life cycle involving a triatomine insect and mammals. Throughout its life cycle, the T. cruzi parasite faces several alternating events of cell division and cell differentiation in which exponential and stationary growth phases play key biological roles. It is well accepted that arrest of the cell division in the epimastigote stage, both in the midgut of the triatomine insect and in vitro, is required for metacyclogenesis, and it has been previously shown that the parasites change the expression profile of several proteins when entering this quiescent stage. However, little is known about the metabolic changes that epimastigotes undergo before they develop into the metacyclic trypomastigote stage. We applied targeted metabolomics to measure the metabolic intermediates in the most relevant pathways for energy metabolism and oxidative imbalance in exponentially growing and stationary growth-arrested epimastigote parasites. We show for the first time that T. cruzi epimastigotes transitioning from the exponential to the stationary phase exhibit a finely tuned adaptive metabolic mechanism that enables switching from glucose to amino acid consumption, which is more abundant in the stationary phase. This metabolic plasticity appears to be crucial for survival of the T. cruzi parasite in the myriad different environmental conditions to which it is exposed during its life cycle.Cell growth, both in natural environments or in in vitro culture, usually presents in two phases: the exponential phase where cells divide at a roughly constant rate, and the stationary phase where cells slow down or stop the cell cycle and division. During the exponential phase, cells go through the well described canonical cell cycle of G 1 3 S 3 G 2 3 M. In the stationary phase, cells leave the regular cell cycle to enter a resting state known as quiescence, which is highly relevant because it corresponds to the physiological state in which most cells from both unicellular and multicellular organisms spend most of their life (1).Trypanosoma cruzi, the etiological agent of Chagas disease, is a protozoan parasite with a complex life cycle involving a triatomine insect and mammals. Throughout its life cycle, the T. cruzi parasite faces several alternated events of cell division and cell differentiation. Briefly, insects are infected during a blood meal from a mammal having non-dividing forms of the parasite, denominated trypomastigotes, present in their blood. Once in the midgut of the triatomine insect, the trypomastigotes differentiate to replicative non-infective epimastigotes, which proliferate and colonize the digestive tube. After the blood meal, nutrients are consumed by the intestinal epithelium, the parasite, and the intestinal microbiota population; therefore, the replicative epimastigotes eventually face nutrient starvation. Under this situation of metabolic stress, cell division is arrested, and the parasites adhe...

A link between mitochondrial gene expression and life stage morphologies in Trypanosoma cruzi

“…Since testing either mitochondrial‐encoded protein abundances or translation of the mitochondrial genome is a technical hurdle, we instead sought to determine whether we would see an increase in respiration that would suggest higher levels of ETC complexes or subunits. Although increases in respiration in nondividing cells is counter‐intuitive, such a phenomenon may occur when substrate availability issues (loss of environmental glucose) profoundly alter T. cruzi metabolism (Barisón et al, ). We analyzed mitochondrial respiration of CL Brener strain cells harvested in exponential and stationary growth phases in normal medium (D0 LIT and D8 LIT, respectively), and abrupt, severe starvation (48H TAU).…”

Structure, Properties, and Function of Glycosomes in Trypanosoma cruzi

“…cruzi, like other dixenous trypanosomatid parasites, undergoes an elaborate life cycle involving extracellular replicative epimastigotes in the triatomine digestive tube, non-replicative extracellular metacyclic and bloodstream trypomastigotes in the insect and mammalian host, respectively, and replicative amastigotes intracellularly in the cytosol of the mammalian cells. The different developmental stages differ importantly in morphology, but also in metabolism to adapt to the large nutritional conditions encountered in the different niches (Maugeri et al, 2011;Barisón et al, 2017;Avila et al, 2018;Marchese et al, 2018;Mattos et al, 2019). Since glycosomes harbor many enzymes of intermediary metabolism as well as enzymes of other metabolic processes which are differentially expressed, glycosomal metabolism has to undergo reprogramming.…”

“…Indeed, levels and activities of glycosomal enzymes differ importantly between bloodstream-form and procyclic T. brucei (Hart et al, 1984). As for T. cruzi, a comparison of the proteome of glycosomes from epimastigotes harvested from the exponential and stationary growth phase, which, respectively, rely primarily on glucose and amino acids as carbon and energy source (Barros-Alvarez et al, 2014;Barisón et al, 2017), showed only small qualitative differences in the repertoire of both intraglycosomal enzymes and proteins in the glycosomal membrane (Acosta et al, 2019). It remains to be determined to what extent quantitative and/or qualitative differences occur in the glycosomal proteome during in vivo differentiation between the different life-cycle stages.…”

A link between mitochondrial gene expression and life stage morphologies inTrypanosoma cruzi

“…Since testing either mitochondrial-250 encoded protein abundances or translation of the mitochondrial genome is a technical hurdle, we 251 instead sought to determine whether we would see an increase in respiration that would suggest 252 higher levels of ETC complexes or subunits. Although increases in respiration in non-dividing 253 cells is counter-intuitive, such a phenomenon may occur when substrate availability issues (loss 254 of environmental glucose) profoundly alter T. cruzi metabolism (Barisón et al, 2017). We 255 analyzed mitochondrial respiration of CL Brener strain cells harvested in exponential and 256 stationary growth phases in normal medium (D0 LIT and D8 LIT, respectively), and abrupt, 257 severe starvation (48H TAU).…”