Stem Cells and the Translational Control of Differentiation: Following the Ribosome Footprints

Ministério da Saúde, Fundação Araucária, FIOCRUZSubmitted by Luciane Willcox ([email protected]) on 2016-10-05T18:16:14Z No. of bitstreams: 1 Stem Cells and the Translational Control of Differentiation.pdf: 361777 bytes, checksum: d72396ea6e1561bce3061897bca3838d (MD5)Approved for entry into archive by Luciane Willcox ([email protected]) on 2016-10-05T18:22:43Z (GMT) No. of bitstreams: 1 Stem Cells and the Translational Control of Differentiation.pdf: 361777 bytes, checksum: d72396ea6e1561bce3061897bca3838d (MD5)Made available in DSpace on 2016-10-05T18:22:43Z (GMT). No. of bitstreams: 1 Stem Cells and the Translational Control of Differentiation.pdf: 361777 bytes, checksum: d72396ea6e1561bce3061897bca3838d (MD5) Previous issue date: 2014-06-20Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Stem cells have been proposed as a promising source for cell therapy. Understanding the biological processes that commit stem cells to differentiate into a particular cell type is essential for the successful repair of injured tissue, and even for whole organogenesis. Cellular differentiation can be modeled as a network of regulatory circuits that direct various steps of gene expression and mediate the spatiotemporal control of a cell’s proteome. In this minireview, we discuss the current aspects of posttranscriptional regulation of gene expression in stem cells, with an emphasis on translational regulation. Several data supports the idea that a significant percentage of genes have their expression controlled at the translational level during stem cell commitment and differentiation. We focus on strategies using polysome and ribosome profiling to measure translational rates and to unravel the dynamics of this process

Modulation of Virulence Factors during <i>Trypanosoma cruzi</i> Differentiation

Chagas disease is a neglected tropical disease caused by Trypanosoma cruzi. This protozoan developed several mechanisms to infect, propagate, and survive in different hosts. The specific expression of proteins is responsible for morphological and metabolic changes in different parasite stages along the parasite life cycle. The virulence strategies at the cellular and molecular levels consist of molecules responsible for mediating resistance mechanisms to oxidative damage, cellular invasion, and immune evasion, performed mainly by surface proteins. Since parasite surface coat remodeling is crucial to invasion and infectivity, surface proteins are essential virulence elements. Understanding the factors involved in these processes improves the knowledge of parasite pathogenesis. Genome sequencing has opened the door to high-throughput technologies, allowing us to obtain a deeper understanding of gene reprogramming along the parasite life cycle and identify critical molecules for survival. This review therefore focuses on proteins regulated during differentiation into infective forms considered virulence factors and addresses the current known mechanisms acting in the modulation of gene expression, emphasizing mRNA signals, regulatory factors, and protein complexes

Trypanosoma cruzi XRNA granules colocalise with distinct mRNP granules at the nuclear periphery

BACKGROUND Eukaryotic ribonucleoprotein (RNP) granules are important for the regulation of RNA fate. RNP granules exist in trypanosomatids; however, their roles in controlling gene expression are still not understood. XRNA is a component of granules in Trypanosoma brucei but has not been investigated in Trypanosoma cruzi. OBJECTIVES This study aimed to investigate the TcXRNA dynamic assembly and its interaction with RNP components under conditions that affect the mRNA availability. METHODS We used in vitro metacyclogenesis of T. cruzi to observe changes in RNP granules during the differentiation process. TcXRNA expression was analysed by Western blot and immunofluorescence. Colocalisation assays were performed to investigate the interaction of TcXRNA with other RNP components. FINDINGS TcXRNA is constantly present during metacyclogenesis and is localised in cytoplasmic granules. TcXRNA does not colocalise with TcDHH1 and TcCAF1 granules in the cytoplasm. However, TcXRNA granules colocalise with mRNP granules at the nuclear periphery when mRNA processing is inhibited. MAIN CONCLUSIONS TcXRNA plays a role in mRNA metabolism as a component of mRNP granules whose assembly is dependent on mRNA availability. TcXRNA granules colocalise with distinct RNP granules at the nuclear periphery, suggesting that the perinuclear region is a regulatory compartment in T. cruzi mRNA metabolism

Biological effects of extracts obtained from Stryphnodendron adstringens on Herpetomonas samuelpessoai

We report the effect of Stryphnodendron adstringens on the trypanosomatid Herpetomonas samuelpessoai. The parasites were grown at 28ºC in a chemically defined medium containing crude extract and fractions at concentrations from 100 to 5000 µg/ml obtained from S. adstringens. Concentrations of 500, 1000, 2500, and 5000 µg/ml both crude extract and semi-purified fraction progressively inhibited the protozoans' growth. At a concentration of 100 µg/ml, crude extract or a semi-purified (F3) fraction did not affect the growth of the protozoans. The F3-9 - F3-12 sub-fractions, at a concentration of 1000 µg/ml, also showed increased inhibitory activity on H. samuelpessoai. The IC50 of the crude extract and the F3 fraction were 538 and 634 µg/ml, respectively. Ultrastructural and enzymatic alterations in the trypanosomatids were also evaluated. H. samuelpessoai cultivated in the presence of IC50 crude extract showed considerable ultrastructural alterations, such as marked mitochondrial swelling with a large number of cristae and evident Golgi complex vesiculation, as observed by transmission electron microscopy. Cells exposed to 538 µg/ml of crude extract at 28ºC for 72 h, showed decreased activity of the enzyme succinate cytochrome c reductase, a typical mitochondrion marker, as compared to untreated cell