IL4I1 Is a Metabolic Immune Checkpoint that Activates the AHR and Promotes Tumor Progression

Immune checkpoint blockade therapy induces the AHR-activating enzyme IL4I1, which promotes tumor progression, through its effects on tumor cell motility and adaptive immunity

Proteome studies for understanding of mitochondrial senescence

Zusammenfassend ist festzustellen, dass ein neues Proteomikverfahren für eine globale und quantitative Analyse von oxidativen Proteinmodifikationen entwickelt wurde, um die mitochondriale freie Radikal-Theorie des Alterns (MFRTA) eingehend zu prüfen. Die MFRTA nimmt an, dass die endogene Konzentration von reaktiven Sauerstoffspezies (ROS) in biologischen Systemen während des Alterns zunimmt. Diese iTRAQ-basierte Studie repräsentiert die erste umfassende Analyse von ROS-induzierten Auswirkungen während des Alterns und der Kalorienrestriktion auf das mitochondriale Proteom. Im Widerspruch zur MFRTA, bestätigen diese Erkenntnisse allerdings keinen massiven Anstieg der Proteinoxidation während des Alterns und lassen eher einen funktionalen Protein-Homöostase Mechanismus vermuten. Zusätzlich konnte ein vermeintlicher hormetischer Effekt der Kalorienrestriktion auf das mitochondriale Proteom mit dieser globalen, ungerichteten, Modifikations-fokussierten Studie detektiert werden.In summary, a new proteomics workflow for global, quantitative and untargeted analyses of oxidative protein modifications was developed to scrutinize the free radical theory of ageing. According to the free radical theory of ageing, an increased endogenous concentration of reactive oxygen species (ROS) damages cellular components during senescence of biological systems and leads to the accumulation of oxidatively damaged biomolecules. This iTRAQ-based study represents the first comprehensive analysis of ROS-induced effects during ageing and CR on the mitochondrial proteome. However, in contradiction to the ROS theory, these findings do not confirm massive increase in protein oxidation during aging and rather suggest a functional protein homeostasis mechanism even at high age in both organisms. Additionally, a putatively hormetic effect of CR could be detected on the mitochondrial proteome with this large-scale temporal modification-centric study

Global role of the membrane protease LonB in Archaea: Potential protease targets revealed by quantitative proteome analysis of a lonB mutant in Haloferax volcanii

The membrane-associated LonB protease is essential for viability in Haloferax volcanii, however, the cellular processes affected by this protease in archaea are unknown. In this study, the impact of a lon conditional mutation (down-regulation) on H. volcanii physiology was examined by comparing proteomes of parental and mutant cells using shotgun proteomics. A total of 1778 proteins were identified (44% of H. volcanii predicted proteome) and 142 changed significantly in amount (≥. 2 fold). Of these, 66 were augmented in response to Lon deficiency suggesting they could be Lon substrates. The "Lon subproteome" included soluble and predicted membrane proteins expected to participate in diverse cellular processes. The dramatic stabilization of phytoene synthase (57 fold) in concert with overpigmentation of lon mutant cells suggests that Lon controls carotenogenesis in H. volcanii. Several hypothetical proteins, which may reveal novel functions and/or be involved in adaptation to extreme environments, were notably increased (300 fold). This study, which represents the first proteome examination of a Lon deficient archaeal cell, shows that Lon has a strong impact on H. volcanii physiology evidencing the cellular processes controlled by this protease in Archaea. Additionally, this work provides a platform for the discovery of novel targets of Lon proteases. Biological Significance: The proteome of a Lon-deficient archaeal cell was examined for the first time showing that Lon has a strong impact on H. volcanii physiology and evidencing the proteins and cellular processes controlled by this protease in Archaea. This work will facilitate future investigations aiming to address Lon function in archaea and provides a platform for the discovery of endogenous targets of the archaeal-type Lon as well as novel targets/processes regulated by Lon proteases. This knowledge will advance the understanding on archaeal physiology and the biological function of membrane proteases in microorganisms.Fil: Cerletti, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Paggi, Roberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Ramallo Guevara, Carina. Ruhr Universität Bochum; AlemaniaFil: Poetsch, Ansgar. Ruhr Universität Bochum; AlemaniaFil: de Castro, Rosana Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; Argentin

Data in support of global role of the membrane protease LonB in Archaea: Potential protease targets revealed by quantitative proteome analysis of a lonB mutant in Haloferax volcanii

This data article provides information in support of the research article “Global role of the membrane protease LonB in Archaea: Potential protease targets revealed by quantitative proteome analysis of a lonB mutant in Haloferax volcanii” [1]. The proteome composition of a wt and a LonB protease mutant strain (suboptimal expression) in the archaeon Haloferax volcanii was assessed by a quantitative shotgun proteomic approach. Membrane and cytosol fractions of H. volcanii strains were examined at two different growth stages (exponential and stationary phase). Data is supplied in the present article. This study represents the first proteome examination of a Lon-deficient cell of the Archaea Domain

Glioblastoma multiforme: Metabolic differences to peritumoral tissue and IDH-mutated gliomas revealed by mass spectrometry imaging.

Kampa JM, Kellner U, Marsching C, et al. Glioblastoma multiforme: Metabolic differences to peritumoral tissue and IDH-mutated gliomas revealed by mass spectrometry imaging. Neuropathology : official journal of the Japanese Society of Neuropathology. 2020;40(6):546-558.Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor. High infiltration rates and poor therapy responses make it the deadliest glioma. The tumor metabolism is known to differ from normal one and is influenced through various factors which can lead to longer survival. Metabolites are small molecules (<1500Da) that display the metabolic pathways in the tissue. To determine the metabolic alterations between tumor and peritumoral tissue in human GBMs, mass spectrometry imaging (MSI) was performed on thin sections from 25 resected tumors. In addition, the GBMs were compared with six gliomas harboring a mutation in the isocitrate dehydrogenase (IDH1) gene (IDH1). With this technique, a manifold of analytes can be easily visualized on a single tissue section. Metabolites were annotated based on their accurate mass using high resolution MSI. Differences in their mean intensities in the tumor and peritumoral areas were statistically evaluated and abundances were visualized on the tissue. Enhanced levels of the antioxidants ascorbic acid, taurine, and glutathione in tumor areas suggest protective effects on the tumor. Increased levels of purine and pyrimidine metabolism compounds in GBM areas indicate the high energy demand. In accordance with these results, enhanced abundances of lactate and glutamine were detected. Moreover, decreased abundance of N-acetylaspartate, a marker for neuronal health, was measured in tumor areas. Obtained metabolic information could potentially support and personalize therapeutic approaches, hence emphasizing the suitability of MSI for GBM research. © 2020 The Authors. Neuropathology published by John Wiley & Sons Australia, Ltd on behalf of Japanese Society of Neuropathology

LonB protease Is a novel regulator of carotenogenesis controlling degradation of phytoene synthase in Haloferax volcanii

The membrane protease LonB is an essential protein in the archaeon Haloferax volcanii and globally impacts its physiology. However, natural substrates of the archaeal Lon protease have not been identified. The whole proteome turnover was examined in a H. volcanii LonB mutant under reduced and physiological protease levels. LC-MS/MS combined with stable isotope labeling was applied for the identification/quantitation of membrane and cytoplasm proteins. Differential synthesis and degradation rates were evidenced for 414 proteins in response to Lon expression. A total of 58 proteins involved in diverse cellular processes showed a degradation pattern (none/very little degradation in the absence of Lon and increased degradation in the presence of Lon) consistent with a LonB substrate, which was further substantiated for several of these candidates by pull-down assays. The most notable was phytoene synthase (PSY), the rate-limiting enzyme in carotenoid biosynthesis. The rapid degradation of PSY upon LonB induction in addition to the remarkable stabilization of this protein and hyperpigmentation phenotype in the Lon mutant strongly suggest that PSY is a LonB substrate. This work identifies for the first time candidate targets of the archaeal Lon protease and establishes proteolysis by Lon as a novel post-translational regulatory mechanism of carotenogenesis.Fil: Cerletti, Micaela. Universidad Nacional de Mar del Plata; ArgentinaFil: Paggi, Roberto Alejandro. Universidad Nacional de Mar del Plata; ArgentinaFil: Troetschel, Christian. Ruhr Universität Bochum; AlemaniaFil: Ferrari, María Celeste. Universidad Nacional de Mar del Plata; ArgentinaFil: Guevara, Carina Ramallo. Ruhr Universität Bochum; AlemaniaFil: Albaum, Stefan. Universitat Bielefeld; AlemaniaFil: Poetsch, Ansgar. Plant Biochemistry, Ruhr University Bochum; AlemaniaFil: de Castro, Rosana Esther. Universidad Nacional de Mar del Plata; Argentin

LonB Protease Is a Novel Regulator of Carotenogenesis Controlling Degradation of Phytoene Synthase in <i>Haloferax volcanii</i>

The membrane protease LonB is an essential protein in the archaeon <i>Haloferax volcanii</i> and globally impacts its physiology. However, natural substrates of the archaeal Lon protease have not been identified. The whole proteome turnover was examined in a <i>H. volcanii</i> LonB mutant under reduced and physiological protease levels. LC–MS/MS combined with stable isotope labeling was applied for the identification/quantitation of membrane and cytoplasm proteins. Differential synthesis and degradation rates were evidenced for 414 proteins in response to Lon expression. A total of 58 proteins involved in diverse cellular processes showed a degradation pattern (none/very little degradation in the absence of Lon and increased degradation in the presence of Lon) consistent with a LonB substrate, which was further substantiated for several of these candidates by pull-down assays. The most notable was phytoene synthase (PSY), the rate-limiting enzyme in carotenoid biosynthesis. The rapid degradation of PSY upon LonB induction in addition to the remarkable stabilization of this protein and hyperpigmentation phenotype in the Lon mutant strongly suggest that PSY is a LonB substrate. This work identifies for the first time candidate targets of the archaeal Lon protease and establishes proteolysis by Lon as a novel post-translational regulatory mechanism of carotenogenesis

Spatial probabilistic mapping of metabolite ensembles in mass spectrometry imaging

Spatial visualization of metabolites in tissues via mass spectrometry imaging can be prone to user perception bias. Here, the authors report the computational framework moleculaR that introduces probabilistic data-dependent molecular mapping of nonrandom spatial patterns of metabolite signals