El silenciamiento de GPAT2 en células MDA-MB-231 afecta el remodelado del ácido araquidónico

La síntesis de novo de glicerolípidos en células de mamífero comienza con la acilación del glicerol-3-fosfato. Este paso esta catalizado por la glicerol-3-fosfato aciltransferasa (GPAT); hasta el momento se han clonado cuatro genes que codifican GPATs. La GPAT2, se clonó por homología de secuencia con GPAT1, sin embrago hemos demostrado que presenta características que la distinguen notablemente de las otras GPATs: se comporta como un antígeno cáncer/ testículo (expresión selectiva en testículo y en tumores de distintas localizaciones), presenta una expresión transitoria en un estadío particular de la meiosis y promueve el fenotipo tumoral incrementando la proliferación y supervivencia celular. Si bien los mecanismos mediante los cuales GPAT2 ejerce su rol funcional, tanto en condiciones fisiológicas como patológicas, no se han dilucidado, nuestros resultados previos indican que juega un rol relevante en el metabolismo del ácido araquidónico.Facultad de Ciencias Médica

El silenciamiento de GPAT2 en células MDA-MB-231 afecta el remodelado del ácido araquidónico

La síntesis de novo de glicerolípidos en células de mamífero comienza con la acilación del glicerol-3-fosfato. Este paso esta catalizado por la glicerol-3-fosfato aciltransferasa (GPAT); hasta el momento se han clonado cuatro genes que codifican GPATs. La GPAT2, se clonó por homología de secuencia con GPAT1, sin embrago hemos demostrado que presenta características que la distinguen notablemente de las otras GPATs: se comporta como un antígeno cáncer/ testículo (expresión selectiva en testículo y en tumores de distintas localizaciones), presenta una expresión transitoria en un estadío particular de la meiosis y promueve el fenotipo tumoral incrementando la proliferación y supervivencia celular. Si bien los mecanismos mediante los cuales GPAT2 ejerce su rol funcional, tanto en condiciones fisiológicas como patológicas, no se han dilucidado, nuestros resultados previos indican que juega un rol relevante en el metabolismo del ácido araquidónico.Facultad de Ciencias Médica

El silenciamiento de GPAT2 en células MDA-MB-231 afecta el remodelado del ácido araquidónico

La síntesis de novo de glicerolípidos en células de mamífero comienza con la acilación del glicerol-3-fosfato. Este paso esta catalizado por la glicerol-3-fosfato aciltransferasa (GPAT); hasta el momento se han clonado cuatro genes que codifican GPATs. La GPAT2, se clonó por homología de secuencia con GPAT1, sin embrago hemos demostrado que presenta características que la distinguen notablemente de las otras GPATs: se comporta como un antígeno cáncer/ testículo (expresión selectiva en testículo y en tumores de distintas localizaciones), presenta una expresión transitoria en un estadío particular de la meiosis y promueve el fenotipo tumoral incrementando la proliferación y supervivencia celular. Si bien los mecanismos mediante los cuales GPAT2 ejerce su rol funcional, tanto en condiciones fisiológicas como patológicas, no se han dilucidado, nuestros resultados previos indican que juega un rol relevante en el metabolismo del ácido araquidónico.Facultad de Ciencias Médica

Secondary Metabolites of Marine Microbes: From Natural Products Chemistry to Chemical Ecology

Marine natural products (MNPs) exhibit a wide range of pharmaceutically relevant bioactivities, including antibiotic, antiviral, anticancer, or anti-inflammatory properties. Besides marine macroorganisms such as sponges, algae, or corals, specifically marine bacteria and fungi have shown to produce novel secondary metabolites (SMs) with unique and diverse chemical structures that may hold the key for the development of novel drugs or drug leads. Apart from highlighting their potential benefit to humankind, this review is focusing on the manifold functions of SMs in the marine ecosystem. For example, potent MNPs have the ability to exile predators and competing organisms, act as attractants for mating purposes, or serve as dye for the expulsion or attraction of other organisms. A large compilation of literature on the role of MNPs in marine ecology is available, and several reviews evaluated the function of MNPs for the aforementioned topics. Therefore, we focused the second part of this review on the importance of bioactive compounds from crustose coralline algae (CCA) and their role during coral settlement, a topic that has received less attention. It has been shown that certain SMs derived from CCA and their associated bacteria are able to induce attachment and/or metamorphosis of many benthic invertebrate larvae, including globally threatened reef-building scleractinian corals. This review provides an overview on bioactivities of MNPs from marine microbes and their potential use in medicine as well as on the latest findings of the chemical ecology and settlement process of scleractinian corals and other invertebrate larvae

Critical role of TLR2 and MyD88 for functional response of macrophages to a group IIA-Secreted phospholipase A2 from snake venom

artículo (arbitrado) -- Universidad de Costa Rica, Instituto de Investigaciones Clodomiro Picado. 2014The snake venom MT-III is a group IIA secreted phospholipase A2 (sPLA2) enzyme with functional and structural similarities with mammalian pro-inflammatory sPLA2s of the same group. Previously, we demonstrated that MT-III directly activates the innate inflammatory response of macrophages, including release of inflammatory mediators and formation of lipid droplets (LDs). However, the mechanisms coordinating these processes remain unclear. In the present study, by using TLR22/2 or MyD882/2 or C57BL/6 (WT) male mice, we report that TLR2 and MyD88 signaling have a critical role in MT-III-induced inflammatory response in macrophages. MT-III caused a marked release of PGE2, PGD2, PGJ2, IL-1b and IL-10 and increased the number of LDs in WT macrophages. In MT-III-stimulated TLR22/2 macrophages, formation of LDs and release of eicosanoids and cytokines were abrogated. In MyD882/2 macrophages, MT-III-induced release of PGE2, IL-1b and IL-10 was abrogated, but release of PGD2 and PGJ2 was maintained. In addition, COX-2 protein expression seen in MT-III-stimulated WT macrophages was abolished in both TLR22/2 and MyD882/2 cells, while perilipin 2 expression was abolished only in MyD882/2 cells. We further demonstrated a reduction of saturated, monounsaturated and polyunsaturated fatty acids and a release of the TLR2 agonists palmitic and oleic acid from MT-III-stimulated WT macrophages compared with WT control cells, thus suggesting these fatty acids as major messengers for MT-III-induced engagement of TLR2/MyD88 signaling. Collectively, our findings identify for the first time a TLR2 and MyD88-dependent mechanism that underlies group IIA sPLA2- induced inflammatory response in macrophages.This investigation was supported by research grants from FAPESP, Sao Paulo, Brazil (www.fapesp.br), grants 11/21341-5 and 10/06345-1, INCTTOX, Sao Paulo, Brazil (www.incttox.com.br), grant 573790/2008-6, CNPq PQ, Brazil (www.cnpq.br), grant 306920/2011-5, Brazil, Spanish Ministery of Science and Innovation, Spain (http://web.micinn.es/), grant BFU2010-18826.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP

Cytosolic group IVA and calcium-independent group VIA phospholipase A2s act on distinct phospholipid pools in zymosan-stimulated mouse peritoneal macrophages

Phospholipase A2s generate lipid mediators that constitute an important component of the integrated response of macrophages to stimuli of the innate immune response. Because these cells contain multiple phospholipase A2 forms, the challenge is to elucidate the roles that each of these forms plays in regulating normal cellular processes and in disease pathogenesis. A major issue is to precisely determine the phospholipid substrates that these enzymes use for generating lipid mediators. There is compelling evidence that group IVA cytosolic phospholipase A2 (cPLA2α) targets arachidonic acid-containing phospholipids but the role of the other cytosolic enzyme present in macrophages, the Ca2+-independent group VIA phospholipase A2 (iPLA2β) has not been clearly defined. We applied mass spectrometry-based lipid profiling to study the substrate specificities of these two enzymes during inflammatory activation of macrophages with zymosan. Using selective inhibitors, we find that, contrary to cPLA2α, iPLA2β spares arachidonate-containing phospholipids and hydrolyzes only those that do not contain arachidonate. Analyses of the lysophospholipids generated during activation reveal that one of the major species produced, palmitoyl-glycerophosphocholine, is generated by iPLA2β, with minimal or no involvement of cPLA 2α. The other major species produced, stearoyl- glycerophosphocholine, is generated primarily by cPLA2α. Collectively, these findings suggest that cPLA2α and iPLA 2β act on different phospholipids during zymosan stimulation of macrophages and that iPLA2β shows a hitherto unrecognized preference for choline phospholipids containing palmitic acid at the sn-1 position that could be exploited for the design of selective inhibitors of this enzyme with therapeutic potential. Copyright © 2014 by The American Association of Immunologists, Inc

Autonomous Multimodal Metabolomics Data Integration for Comprehensive Pathway Analysis and Systems Biology.

Comprehensive metabolomic data can be achieved using multiple orthogonal separation and mass spectrometry (MS) analytical techniques. However, drawing biologically relevant conclusions from this data and combining it with additional layers of information collected by other omic technologies present a significant bioinformatic challenge. To address this, a data processing approach was designed to automate the comprehensive prediction of dysregulated metabolic pathways/networks from multiple data sources. The platform autonomously integrates multiple MS-based metabolomics data types without constraints due to different sample preparation/extraction, chromatographic separation, or MS detection method. This multimodal analysis streamlines the extraction of biological information from the metabolomics data as well as the contextualization within proteomics and transcriptomics data sets. As a proof of concept, this multimodal analysis approach was applied to a colorectal cancer (CRC) study, in which complementary liquid chromatography-mass spectrometry (LC-MS) data were combined with proteomic and transcriptomic data. Our approach provided a highly resolved overview of colon cancer metabolic dysregulation, with an average 17% increase of detected dysregulated metabolites per pathway and an increase in metabolic pathway prediction confidence. Moreover, 95% of the altered metabolic pathways matched with the dysregulated genes and proteins, providing additional validation at a systems level. The analysis platform is currently available via the XCMS Online ( XCMSOnline.scripps.edu )

Microbial Metabolite 3-Indolepropionic Acid Mediates Immunosuppression

The microbial-derived metabolite, 3-indolepropionic acid (3-IPA), has been intensely studied since its origins were discovered in 2009; however, 3-IPA’s role in immunosuppression has had limited attention. Untargeted metabolomic analyses of T-cell exhaustion and immunosuppression, represented by dysfunctional under-responsive CD8+ T cells, reveal a potential role of 3-IPA in these responses. T-cell exhaustion was examined via infection of two genetically related mouse strains, DBA/1J and DBA/2J, with lymphocytic choriomeningitis virus (LCMV) Clone 13 (Cl13). The different mouse strains produced disparate outcomes driven by their T-cell responses. Infected DBA/2J presented with exhausted T cells and persistent infection, and DBA/1J mice died one week after infection from cytotoxic T lymphocytes (CTLs)-mediated pulmonary failure. Metabolomics revealed over 70 metabolites were altered between the DBA/1J and DBA/2J models over the course of the infection, most of them in mice with a fatal outcome. Cognitive-driven prioritization combined with statistical significance and fold change were used to prioritize the metabolites. 3-IPA, a tryptophan-derived metabolite, was identified as a high-priority candidate for testing. To test its activity 3-IPA was added to the drinking water of the mouse models during LCMV Cl13 infection, with the results showing that 3-IPA allowed the mice to survive longer. This negative immune-modulation effect might be of interest for the modulation of CTL responses in events such as autoimmune diseases, type I diabetes or even COVID-19. Moreover, 3-IPA’s bacterial origin raises the possibility of targeting the microbiome to enhance CTL responses in diseases such as cancer and chronic infection