Molecular Protozoology

Summary

Lipids are the major components of biological membranes, fulfilling structural functions, energy storage and intra-and intercellular signaling. Comprise a large group of compounds including fatty acids, sphingolipids and sterols glycerolipids, among others. Our laboratory is focused, from different perspectives, to the study of biochemistry and molecular biology of lipid metabolism in different eukaryotic microorganisms (protists). This is carried out using bioinformatic approaches, molecular biology and genetics and a wide range of analytical methodologies for the study of lipid species (Gaseous and Liquid Chromatography coupled to Mass Spectrometry and GC/MS- -LC/MS-MS Chromatography thin layer, etc.).

Research Lines

Identification of drug targets in the lipid metabolism of trypanosomatids.

Our group has depicted the fatty acid and sphingolipid metabolisms in trypanosomatids. These organisms are responsible of serious human and animal diseases such as Chagas disease, caused by Trypanosoma cruzi, sleeping sickness (T. brucei) and leishmaniasis (Leishmania spp.). By mean of genetic approaches and the design of specific inhibitors, we have identified that two enzymes of the pathway are essential for the parasites, the D9 and D12 desaturases. We continue analyzing the essentiality of other desaturases and elongases, and developing new drugs, more efficacious and with potential clinical use. A new line of research focuses on the enzymes involved in lipoic acid biosynthesis.

Sterol metabolism in ciliate protozoa.

Another line of work focuses on the metabolism of sterols in the ciliates Tetrahymena thermophila and Paramecium tetraurelia. T. thermophila is able of taking up sterols from the media and modifying them by a series of desaturations and dealkylation. By using reverse genetic approaches such as feeding-RNA interference and knock out mutagenesis, we succeeded identifying the D5 and D6 desaturases and the dealkylating enzyme, which is the first one described in nature. The consequence of these reactions is the synthesis of pro-vitamin D, which is accumulated in the ciliate membrane. This has obvious biotechnological applications in the creation of functional foods of animal origin, with the dual benefit of reducing cholesterol and the concomitant enrichment in pro-vitamin D. We are also studying the synthesis of glycogen and triglycerides, which act as carbon and energy stores. We have determined that glycerol (a cheap by-product of the biodiesel industry) is a good carbon source for the ciliates, repressing the accumulation of glycogen, but stimulating the synthesis of triglycerides, which can be used in biodiesel production.

Selected Publications

  •  Sterols metabolism in the filastereanCapsasporaowczarzaki has features that resemble both fungi and animals (2016) Najle SR, Molina MC, Ruiz-Trillo I, Uttaro AD. Open Biol.6, 160029.
  • Biosynthesis of very long chain fatty acids in Trypanosomacruzi(2015) Livore VI, Uttaro AD. Parasitol. Res. 114, 265-271.
  • Acquisition and Biosynthesis of Saturated and Unsaturated Fatty Acids by Trypanosomatids (2014) Antonio D. Uttaro. Mol. Biochem. Parasitol.196, 61–70.
  • Synergistic effect of inhibitors of fatty acid desaturases on Trypanosoma parasites (2013) Andrés Alloatti, Karina EJ. Tripodi, Antonio D. Uttaro. Parasitol. Res. 112, 3289–3294.
  • Najle SR, Nusblat AD, Nudel CB, Uttaro AD. (2013) The Sterol-C7 desaturase from the ciliate Tetrahymena thermophila is a Rieske Oxygenase, which is highly conserved in animals. Mol Biol Evol. 30(7):1630-43. doi: 10.1093/molbev/mst076.
  • Vacchina P, Tripodi KE, Escalante AM, Uttaro AD. (2012) Characterization of bifunctional sphingolipid Δ4-desaturases/C4-hydroxylases of trypanosomatids by liquid chromatography-electrospray tandem mass spectrometry. Mol Biochem Parasitol 184(1):29-38
  • Alloatti, A., Gupta, S., Gualdrón-López, M., Nguewa, PA., Altabe, S.G., Deumer, G., Wallemacq, P, Michels, PAM.,Uttaro, A.D. (2011). Stearoyl-CoA desaturase is an essential enzyme for the parasitic protist Trypanosoma brucei. Biochem. Biophys. Res. Commun. 412, 286–290.
  • Alloatti, A., Uttaro, A.D. (2011). Highly specific methyl-end fatty-acid desaturases of trypanosomatids. Mol. Biochem. Parasitol. 175, 126-132.
  • Tomazic, ML., Najle, SR., Nusblat, AD., Uttaro, AD. Nudel, CB. (2011). A Novel Sterol Desaturase-Like Protein Promoting Dealkylation of Phytosterols in Tetrahymena thermophila. Eukaryotic Cell 10, 423-434.
  • Alloatti, A., Gupta, S., Gualdrón-López, M., Igoillo-Esteve, M., Nguewa, P.A., Deumer, G., Wallemacq, P., Altabe, S.G., Michels, P.A.M., and Uttaro, A.D. (2010). Genetic and chemical evaluation of Trypanosoma brucei oleate desaturase as a candidate drug target. PLoS ONE 5, e14239
  • Nusblat, A.D., Najle, S.R., Tomazic, M.L., Uttaro, A.D., and Nudel, C.B. (2009). C5(6) sterol desaturase from Tetrahymena thermophila: gene identification and knockout, sequence analysis and comparison to other C5(6) sterol desaturases. Eukaryotic Cell 8, 1287-1297.
  • Alloatti, A., Testero, S.A., and Uttaro, A.D. (2009). Chemical evaluation of fatty acid desaturases as drug targets in Trypanosoma cruzi. Int. J. Parasitol. 39, 985-993.

Collaborators

  • Alejandro Nusblat y Clara Nudel, Facultad de Farmacia y Bioquímica, UBA Paul AM. Michels, Christian de Duve Institute and Université Catholique de Lovaine, Bruselas, Bélgica.

Grants

  • FONCyT, PICT-2014 Nº 1311 Tema: Análisis transcriptómico y funcional de la respuesta al colesterol exógeno en el ciliado de interés biotecnológico Tetrahymenathermophila.
  • Agencia Nacional de Promoción Científica y Tecnológica. PICT 2012 - 1301. "Evaluación de la biosíntesis de lipoato como blanco quimioterapéutico para el diseño de drogas de efecto pleiotrópico en tripanosomas".

Director

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http://www.ibr-conicet.gov.ar/wp-content/uploads/2013/12/Uttaro.jpg

Uttaro, Antonio D.
Core CCT
Email: uttaro@ibr-conicet.gov.ar
Phone: +54 341 4237070
Office Extension: 635
Laboratory Extension: 624

Researchers

  • Sebastián R. Najle
  • Paola Vacchina

Doctoral fellows

  • Josefina Hernandez
  • Nicolás Garcia Siburu
  • Vanesa Frea

Undergraduate Students

  • Alejandro P. Pariani

Imágenes

Microscopía confocal de células del ciliado Tetrahymena thermophila. En azul, tinción del micro y macronúcleo. En verde, localización perinuclear y en microcuerpos de una desaturasa de esteroles fusionada a la proteína verde fluorescente.

Microscopia confocal mostrando la localización de la desaturasa (verde) y de fagosomas conteniendo bacterias fluorescentes rojas (derecha); Tinción con Nile Red, mostrando estructuras membranosas (rojo) y cuerpos lipídicos o “lipid droplets” en amarillo (izquierda).