Clinical and pathological characteristics associated with the presence of the IS6110 Mycobacterim tuberculosis transposon in neoplastic cells from non-small cell lung cancer patients.

Lung cancer (LC) and pulmonary tuberculosis (TB) are the deadliest neoplastic and bacterial infectious diseases worldwide, respectively. Clinicians and pathologists have long discussed the co-existence of LC and TB, and several epidemiologic studies have presented evidence indicating that TB could be associated with the development of LC, particularly adenocarcinoma. Nonetheless, this data remains controversial, and the mechanism which could underlie the association remains largely unexplored. Some bioinformatic studies have shown that human cancer biopsies have a very high frequency of bacterial DNA integration; since Mycobacterium Tuberculosis (MTb) is an intracellular pathogen, it could play an active role in the cellular transformation. Our group performed an exploratory study in a cohort of 88 LC patients treated at the Instituto Nacional de Cancelorogía (INCan) of Mexico City to evaluate the presence of MTb DNA in LC tissue specimens. For the first time, our results show the presence of the MTb IS6110 transposon in 40.9% (n = 36/88) of patients with lung adenocarcinomas. Additionally, through in-situ PCR we identified the presence of IS6110 in the nuclei of tumor cells. Furthermore, shotgun sequencing from two samples identified traces of MTb genomes present in tumor tissue, suggesting that similar Mtb strains could be infecting both patients.

A novel, sequencing-free strategy for the functional characterization of Taenia solium proteomic fingerprint.

The flatworm Taenia solium causes human and pig cysticercosis. When cysticerci are established in the human central nervous system, they cause neurocysticercosis, a potentially fatal disease. Neurocysticercosis is a persisting public health problem in rural regions of Mexico and other developing countries of Latin America, Asia, and Africa, where the infection is endemic. The great variability observed in the phenotypic and genotypic traits of cysticerci result in a great heterogeneity in the patterns of molecules secreted by them within their host. This work is aimed to identify and characterize cysticercal secretion proteins of T. solium cysticerci obtained from 5 naturally infected pigs from Guerrero, Mexico, using 2D-PAGE proteomic analysis. The isoelectric point (IP) and molecular weight (MW) of the spots were identified using the software ImageMaster 2D Platinum v.7.0. Since most secreted proteins are impossible to identify by mass spectrometry (MS) due to their low concentration in the sample, a novel strategy to predict their sequence was applied. In total, 108 conserved and 186 differential proteins were identified in five cysticercus cultures. Interestingly, we predicted the sequence of 14 proteins that were common in four out of five cysticercus cultures, which could be used to design vaccines or diagnostic methods for neurocysticercosis. A functional characterization of all sequences was performed using the algorithms SecretomeP, SignalP, and BlastKOALA. We found a possible link between signal transduction pathways in parasite cells and human cancer due to deregulation in signal transduction pathways. Bioinformatics analysis also demonstrated that the parasite release proteins by an exosome-like mechanism, which could be of biological interest.

Microbiome-MX 2018: microbiota and microbiome opportunities in Mexico, a megadiverse country.

A weekly conference series paired with lectures entitled "Microbiome-MX: exploring the Microbiota and Microbiome Research in Mexico" was organized to provide a multidisciplinary overview of the most recent research done in Mexico using high-throughput sequencing. Scientists and postgraduate students from several disciplines such as microbiology, bioinformatics, virology, immunology, nutrition, and medical genomics gathered to discuss state of the art in each of their respective subjects of expertise, as well as advances, applications and new opportunities on microbiota/microbiome research. In particular, high-throughput sequencing is a crucial tool to understand the challenges of a megadiverse developing country as Mexico, and moreover to know the scientific capital and capabilities available for collaboration. The conference series addressed three main topics important for Mexico: i) the complex role of microbiota in health and prevalent diseases such as obesity, diabetes, inflammatory bowel disease, tuberculosis, HIV, autoimmune diseases and gastric cancer; ii) the use of local, traditional and prehispanic products as pre/probiotics to modulate the microbiota and improve human health; and iii) the impact of the microbiota in shaping the biodiversity of economically important terrestrial and marine ecosystems. Herein, we summarize the contributions that Mexican microbiota/microbiome research is making to the global trends, describing the highlights of the conferences and lectures, rather than a review of the state-of-the-art of this research. This meeting report also presents the efforts of a multidisciplinary group of scientist to encourage collaborations and bringing this research field closer for younger generations.

The CDR1 and Other Regions of Immunoglobulin Light Chains are Hot Spots for Amyloid Aggregation.

Immunoglobulin light chain-derived (AL) amyloidosis is a debilitating disease without known cure. Almost nothing is known about the structural factors driving the amyloidogenesis of the light chains. This study aimed to identify the fibrillogenic hotspots of the model protein 6aJL2 and in pursuing this goal, two complementary approaches were applied. One of them was based on several web-based computational tools optimized to predict fibrillogenic/aggregation-prone sequences based on different structural and biophysical properties of the polypeptide chain. Then, the predictions were confirmed with an ad-hoc synthetic peptide library. In the second approach, 6aJL2 protein was proteolyzed with trypsin, and the products incubated in aggregation-promoting conditions. Then, the aggregation-prone fragments were identified by combining standard proteomic methods, and the results validated with a set of synthetic peptides with the sequence of the tryptic fragments. Both strategies coincided to identify a fibrillogenic hotspot located at the CDR1 and ß-strand C of the protein, which was confirmed by scanning proline mutagenesis analysis. However, only the proteolysis-based strategy revealed additional fibrillogenic hotspots in two other regions of the protein. It was shown that a fibrillogenic hotspot associated to the CDR1 is also encoded by several κ and λ germline variable domain gene segments. Some parts of this study have been included in the chapter "The Structural Determinants of the Immunoglobulin Light Chain Amyloid Aggregation", published in Physical Biology of Proteins and Peptides, Springer 2015 (ISBN 978-3-319-21687-4).

Structural Basis for the Limited Response to Oxidative and Thiol-Conjugating Agents by Triosephosphate Isomerase From the Photosynthetic Bacteria Synechocystis.

In plants, the ancestral cyanobacterial triosephosphate isomerase (TPI) was replaced by a duplicated version of the cytosolic TPI. This isoform acquired a transit peptide for chloroplast localization and functions in the Calvin-Benson cycle. To gain insight into the reasons for this gene replacement in plants, we characterized the TPI from the photosynthetic bacteria Synechocystis (SyTPI). SyTPI presents typical TPI enzyme kinetics profiles and assembles as a homodimer composed of two subunits that arrange in a (ß-α)8 fold. We found that oxidizing agents diamide (DA) and H2O2, as well as thiol-conjugating agents such as oxidized glutathione (GSSG) and methyl methanethiosulfonate (MMTS), do not inhibit the catalytic activity of SyTPI at concentrations required to inactivate plastidic and cytosolic TPIs from the plant model Arabidopsis thaliana (AtpdTPI and AtcTPI, respectively). The crystal structure of SyTPI revealed that each monomer contains three cysteines, C47, C127, and C176; however only the thiol group of C176 is solvent exposed. While AtcTPI and AtpdTPI are redox-regulated by chemical modifications of their accessible and reactive cysteines, we found that C176 of SyTPI is not sensitive to redox modification in vitro. Our data let us postulate that SyTPI was replaced by a eukaryotic TPI, because the latter contains redox-sensitive cysteines that may be subject to post-translational modifications required for modulating TPI's enzymatic activity.

Experimental and Theoretical Approaches To Investigate the Immunogenicity of Taenia solium-Derived KE7 Antigen.

Taenia solium cysticercosis, a parasitic disease that affects human health in various regions of the world, is preventable by vaccination. Both the 97-amino-acid-long KETc7 peptide and its carboxyl-terminal, 18-amino-acid-long sequence (GK-1) are found in Taenia crassiceps Both peptides have proven protective capacity against cysticercosis and are part of the highly conserved, cestode-native, 264-amino-acid long protein KE7. KE7 belongs to a ubiquitously distributed family of proteins associated with membrane processes and may participate in several vital cell pathways. The aim of this study was to identify the T. solium KE7 (TsKE7) full-length protein and to determine its immunogenic properties. Recombinant TsKE7 (rTsKE7) was expressed in Escherichia coli Rosetta2 cells and used to obtain mouse polyclonal antibodies. Anti-rTsKE7 antibodies detected the expected native protein among the 350 spots developed from T. solium cyst vesicular fluid in a mass spectrometry-coupled immune proteomic analysis. These antibodies were then used to screen a phage-displayed 7-random-peptide library to map B-cell epitopes. The recognized phages displayed 9 peptides, with the consensus motif Y(F/Y)PS sequence, which includes YYYPS (named GK-1M, for being a GK-1 mimotope), exactly matching a part of GK-1. GK-1M was recognized by 58% of serum samples from cysticercotic pigs with 100% specificity but induced weak protection against murine cysticercosis. In silico analysis revealed a universal T-cell epitope(s) in native TsKE7 potentially capable of stimulating cytotoxic T lymphocytes and helper T lymphocytes under different major histocompatibility complex class I and class II mouse haplotypes. Altogether, these results provide a rationale for the efficacy of the KETc7, rTsKE7, and GK-1 peptides as vaccines.