Redox regulation of methylthioadenosine phosphorylase in liver cells: molecular mechanism and functional implications

MTAP (5'-methylthioadenosine phosphorylase) catalyses the reversible phosphorolytic cleavage of methylthioadenosine leading to the production of methylthioribose-1-phosphate and adenine. Deficient MTAP activity has been correlated with human diseases including cirrhosis and hepatocellular carcinoma. In the present study we have investigated the regulation of MTAP by ROS (reactive oxygen species). The results of the present study support the inactivation of MTAP in the liver of bacterial LPS (lipopolysaccharide)-challenged mice as well as in HepG2 cells after exposure to t-butyl hydroperoxide. Reversible inactivation of purified MTAP by hydrogen peroxide results from a reduction of V(max) and involves the specific oxidation of Cys(136) and Cys(223) thiols to sulfenic acid that may be further stabilized to sulfenyl amide intermediates. Additionally, we found that Cys(145) and Cys(211) were disulfide bonded upon hydrogen peroxide exposure. However, this modification is not relevant to the mediation of the loss of MTAP activity as assessed by site-directed mutagenesis. Regulation of MTAP by ROS might participate in the redox regulation of the methionine catabolic pathway in the liver. Reduced MTA (5'-deoxy-5'-methylthioadenosine)-degrading activity may compensate for the deficient production of the precursor S-adenosylmethionine, allowing maintenance of intracellular MTA levels that may be critical to ensure cellular adaptation to physiopathological conditions such as inflammation

Diversity of Acari and Collembola along a pollution gradient in soils of a pre-pyrenean forest ecosystem

Mites and springtails are important members of soil mesofauna and have been proven to be good bioindicators of airborne pollutants. We studied the surrounding area of a steel mill located in a mountain valley of North Spain. Previous studies had documented the existence of a pollution gradient in this area due to the emissions of the factory, thus providing an interesting site to investigate the potential effects of pollutants (heavy metals and nitrogen) on soil biodiversity. The density of Acari and Collembola significantly decreased with the increase in concentration of Cr, Mn, Zn, Cd and Pb. Mites appeared to be more sensitive to heavy metal pollution than springtails. Likewise, the density of these microarthropoda was lower in those soils exhibiting higher nitrogen content. The species composition of the community of Acari and Collembola changed according to heavy metal pollution. Significant differences in abundance, species richness and diversity were observed between the communities of the sampling sites. Some species were exclusive of the less polluted sites, while other appeared in the most contaminated ones. This different response of soil mesofauna to pollutants suggests that some mite or springtail species could be used as bioindicators of heavy metal pollution

Functional proteomics of nonalcoholic steatohepatitis: mitochondrial proteins as targets of S-adenosylmethionine

Recent work shows that S-adenosylmethionine (AdoMet) helps maintain normal liver function as chronic hepatic deficiency results in spontaneous development of steatohepatitis and hepatocellular carcinoma. The mechanisms by which these nontraditional functions of AdoMet occur are unknown. Here, we use knockout mice deficient in hepatic AdoMet synthesis (MAT1A(-/-)) to study the proteome of the liver during the development of steatohepatitis. One hundred and seventeen protein spots, differentially expressed during the development of steatohepatitis, were selected and identified by peptide mass fingerprinting. Among them, 12 proteins were found to be affected from birth, when MAT1A(-/-) expression is switched on in WT mouse liver, to the rise of histological lesions, which occurs at approximately 8 months. Of the 12 proteins, 4 [prohibitin 1 (PHB1), cytochrome c oxidase I and II, and ATPase beta-subunit] have known roles in mitochondrial function. We show that the alteration in expression of PHB1 correlates with a loss of mitochondrial function. Experiments in isolated rat hepatocytes indicate that AdoMet regulates PHB1 content, thus suggesting ways by which steatohepatitis may be induced. Importantly, we found the expression of these mitochondrial proteins was abnormal in obob mice and obese patients who are at risk for nonalcoholic steatohepatitis

Omics approaches in pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma, which represents 80% of pancreatic cancers, is mainly diagnosed when treatment with curative intent is not possible. Consequently, the overall five-year survival rate is extremely dismal—around 5% to 7%. In addition, pancreatic cancer is expected to become the second leading cause of cancer-related death by 2030. Therefore, advances in screening, prevention and treatment are urgently needed. Fortunately, a wide range of approaches could help shed light in this area. Beyond the use of cytological or histological samples focusing in diagnosis, a plethora of new approaches are currently being used for a deeper characterization of pancreatic ductal adenocarcinoma, including genetic, epigenetic, and/or proteo-transcriptomic techniques. Accordingly, the development of new analytical technologies using body fluids (blood, bile, urine, etc.) to analyze tumor derived molecules has become a priority in pancreatic ductal adenocarcinoma due to the hard accessibility to tumor samples. These types of technologies will lead us to improve the outcome of pancreatic ductal adenocarcinoma patients

Molecular profiling of hepatocellular carcinoma in mice with a chronic deficiency of hepatic s-adenosylmethionine: relevance in human liver diseases

S-adenosylmethionine arises as a central molecule in the preservation of liver homeostasis as a chronic hepatic deficiency results in spontaneous development of steatohepatitis and hepatocellular carcinoma. In the present work, we have attempted a comprehensive analysis of proteins associated with hepatocarcinogenesis in MAT1A knock out mice using a combination of two-dimensional electrophoresis and mass spectrometry, to then apply the resulting information to identify hallmarks of human HCC. Our results suggest the existence of individual-specific factors that might condition the development of preneoplastic lesions. Proteomic analysis allowed the identification of 151 differential proteins in MAT1A-/- mice tumors. Among all differential proteins, 27 changed in at least 50% of the analyzed tumors, and some of these alterations were already detected months before the development of HCC in the KO liver. The expression level of genes coding for 13 of these proteins was markedly decreased in human HCC. Interestingly, seven of these genes were also found to be down-regulated in a pretumoral condition such as cirrhosis, while depletion of only one marker was assessed in less severe liver disorders

Smelling the dark proteome: Functional characterization of PITH domain-containing protein 1 (C1orf128) in olfactory metabolism

The Human Proteome Project (HPP) consortium aims to functionally characterize the dark proteome. On the basis of the relevance of olfaction in early neurodegeneration, we have analyzed the dark proteome using data mining in public resources and omics data sets derived from the human olfactory system. Multiple dark proteins localize at synaptic terminals and may be involved in amyloidopathies such as Alzheimer’s disease (AD). We have characterized the dark PITH domain-containing protein 1 (PITHD1) in olfactory metabolism using bioinformatics, proteomics, in vitro and in vivo studies, and neuropathology. PITHD1–/– mice exhibit olfactory bulb (OB) proteome changes related to synaptic transmission, cognition, and memory. OB PITHD1 expression increases with age in wild-type (WT) mice and decreases in Tg2576 AD mice at late stages. The analysis across 6 neurological disorders reveals that olfactory tract (OT) PITHD1 is specifically upregulated in human AD. Stimulation of olfactory neuroepithelial (ON) cells with PITHD1 alters the ON phosphoproteome, modifies the proliferation rate, and induces a pro-inflammatory phenotype. This workflow applied by the Spanish C-HPP and Human Brain Proteome Project (HBPP) teams across the ON-OB-OT axis can be adapted as a guidance to decipher functional features of dark proteins. Data are available via ProteomeXchange with identifiers PXD018784 and PXD021634

Encapsulation of MSCs and GDNF in an Injectable Nanoreinforced Supramolecular Hydrogel for Brain Tissue Engineering

The co-administration of glial cell line-derived neurotrophic factor (GDNF) and mesenchymal stem cells (MSCs) in hydrogels (HGs) has emerged as a powerful strategy to enhance the efficient integration of transplanted cells in Parkinson's disease (PD). This strategy could be improved by controlling the cellular microenvironment and biomolecule release and better mimicking the complex properties of the brain tissue. Here, we develop and characterize a drug delivery system for brain repair where MSCs and GDNF are included in a nanoparticle-modified supramolecular guest-host HA HG. In this system, the nanoparticles act as both carriers for the GDNF and active physical crosslinkers of the HG. The multifunctional HG is mechanically compatible with brain tissue and easily injectable. It also protects GDNF from degradation and achieves its controlled release over time. The cytocompatibility studies show that the developed biomaterial provides a friendly environment for MSCs and presents good compatibility with PC12 cells. Finally, using RNA-sequencing (RNA-seq), we investigated how the three-dimensional (3D) environment, provided by the nanostructured HG, impacted the encapsulated cells. The transcriptome analysis supports the beneficial effect of including MSCs in the nanoreinforced HG. An enhancement in the anti-inflammatory effect of MSCs was observed, as well as a differentiation of the MSCs toward a neuron-like cell type. In summary, the suitable strength, excellent self healing properties, good biocompatibility, and ability to boost MSC regenerative potential make this nanoreinforced HG a good candidate for drug and cell administration to the brain

Behavioral interactions and trophic overlap between invasive signal crayfish Pacifastacus leniusculus (Decapoda, Astacidae) and native fishes in iberian rivers

The signal crayfish Pacifastacus leniusculus Dana, 1852 is a successful invasive species in the Iberian Peninsula. This is of particular conservation concern, as fish fauna is highly endemic and also threatened within this ecoregion. The aim of this study was to analyze behavioral interactions and trophic overlap between signal crayfish and native fishes in Iberian rivers (northern Spain). Video cameras were used to record fish "dominance/evasion" after spatial encounters with crayfish. Diet composition and isotopic signatures (¿13C and ¿15N) were compared to evaluate the niche overlap. Fish were dominant in 25% of the encounters with juvenile crayfish, whereas this percentage was only 4% with adult crayfish. Observations showed a high fish "evasion" response for Pyrenean stone loach Barbatula quignardi (B¿cescu-Me¿ter, 1967) (>30%). Dietary results showed a high trophic overlap between signal crayfish with the pelagic Pyrenean minnow Phoxinus bigerri Kottelat, 2007 and the benthic loach. However, the isotopic niche overlap was low, with brown trout Salmo trutta L., 1758 showing the highest area (only 0.1 ¿2). Overall, our findings suggest that interferences may occur with native species for food (i.e., benthic invertebrates). Consequently, measures should be applied to control invasive crayfish in Iberian rivers

Medidas para reducir la exposición de los ciclistas a los principales contaminantes atmosféricos urbanos

Recoge los principales resultados generados durante la realización del proyecto LIFE+RESPIRA, llevado a cabo en la ciudad de Pamplona (Navarra, España) por un equipo interdisciplinar constituido por más de 30 investigadores pertenecientes a la Universidad de Navarra, el Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) y Gestión Ambiental de Navarra (GAN-NIK). El libro, que se ha publicado en castellano y en inglés, se ha dividido en 7 capítulos: 1. ¿Ciudades sostenibles? 2. Exposición de los ciudadanos a la contaminación atmosférica 3. Papel de la vegetación urbana en la calidad del aire 4. Modelos de alta resolución para evaluar la calidad del aire 5. Impactos de la contaminación urbana 6. Movilidad y sostenibilidad urbanas 7. Comunicación y educación ambiental. Este libro pretende ser una guía de utilidad para científicos, gestores y ciudadanos, aportando un conjunto de herramientas que permitan mejorar la calidad de vida de nuestras ciudades. Además, quiere rendir un homenaje a todos los voluntarios ciclistas que han participado en dicho proyecto y que son los verdaderos artífices del mismo, ya que gracias a su dedicación incondicional durante más de dos años, han proporcionado una cantidad ingente de datos sobre la calidad del aire de la ciudad de Pamplona

Reduction of exposure of cyclists to urban air pollution

This book collects the main outcomes that were generated during the implementation of the LIFE+RESPIRA project (LIFE13 ENV/ES/000417), carried out in the city of Pamplona, Navarra, Spain. The research was conducted by a cross-functional team made up of more than 30 researchers belonging to three entities: The University of Navarra, the Centre for Energy, Environmental and Technological Research (CIEMAT) and Environmental Management of Navarra (GAN-NIK)