John A. Bowden, Alan Heckert, Candice Z. Ulmer, Christina M. Jones, Jeremy P. Koelmel, Laila Abdullah, Linda Ahonen, Yazen Alnouti, Aaron M. Armando, John M. Asara, Takeshi Bamba, John R. Barr, Jonas Bergquist, Christoph H. Borchers, Joost Brandsma, Susanne B. Breitkopf, Tomas Cajka, Amaury Cazenave-Gassiot, Antonio Checa, Michelle A. Cinel, Romain A. Colas, Serge Cremers, Edward A. Dennis, James E. Evans, Alexander Fauland, Oliver Fiehn, Michael S. Gardner, Timothy J. Garrett, Katherine H. Gotlinger, Jun Han, Yingying Huang, Aveline Huipeng Neo, Tuulia Hyötyläinen, Yoshihiro Izumi, Hongfeng Jiang, Houli Jiang, Jiang Jiang, Maureen Kachman, Reiko Kiyonami, Kristaps Klavins, Christian Klose, Harald C. Köfeler, Johan Kolmert, Therese Koal, Grielof Koster, Zsuzsanna Kuklenyik, Irwin J. Kurland, Michael Leadley, Karen Lin, Krishna Rao Maddipati, Danielle McDougall, Peter J. Meikle, Natalie A. Mellett, Cian Monnin, M. Arthur Moseley, Renu Nandakumar, Matej Oresic, Rainey Patterson, David Peake, Jason S. Pierce, Martin Post, Anthony D. Postle, Rebecca Pugh, Yunping Qiu, Oswald Quehenberger, Parsram Ramrup, Jon Rees, Barbara Rembiesa, Denis Reynaud, Mary R. Roth, Susanne Sales, Kai Schuhmann, Michal Laniado Schwartzman, Charles N. Serhan, Andrej Shevchenko, Stephen E. Somerville, Lisa St. John-Williams, Michal A. Surma, Hiroaki Takeda, Rhishikesh Thakare, J. Will Thompson, Federico Torta, Alexander Triebl, Martin Trötzmüller, S. J. Kumari Ubhayasekera, Dajana Vuckovic, Jacquelyn M. Weir, Ruth Welti, Markus R. Wenk, Craig E. Wheelock, Libin Yao, Min Yuan, Xueqing Heather Zhao, Senlin Zhou

Glucose metabolism is remodeled in cancer, but the global pattern of cancer-specific metabolic changes remains unclear. Here we show, using the comprehensive measurement of metabolic enzymes by large-scale targeted proteomics, that the metabolism both carbon and nitrogen is altered during the malignant progression of cancer. The fate of glutamine nitrogen is shifted from the anaplerotic pathway into the TCA cycle to nucleotide biosynthesis, with this shift being controlled by glutaminase (GLS1) and phosphoribosyl pyrophosphate amidotransferase (PPAT). Interventions to reduce the PPAT/GLS1 ratio suppresses tumor growth of many types of cancer. A meta-analysis reveals that PPAT shows the strongest correlation with malignancy among all metabolic enzymes, in particular in neuroendocrine cancer including small cell lung cancer (SCLC). PPAT depletion suppresses the growth of SCLC lines. A shift in glutamine fate may thus be required for malignant progression of cancer, with modulation of nitrogen metabolism being a potential approach to SCLC treatment.

Adiponectin, an adipocyte-derived circulating protein, accumulates in vasculature, heart, and skeletal muscles through interaction with a unique glycosylphosphatidylinositol-anchored cadherin, T-cadherin. Recent studies have demonstrated that such accumulation is essential for adiponectin-mediated cardiovascular protection. Here, we demonstrate that the adiponectin/T-cadherin system enhances exosome biogenesis and secretion, leading to the decrease of cellular ceramides. Adiponectin accumulated inside multivesicular bodies, the site of exosome generation, in cultured cells and in vivo aorta, and also in exosomes in conditioned media and in blood, together with T-cadherin. The systemic level of exosomes in blood was significantly affected by adiponectin or T-cadherin in vivo. Adiponectin increased exosome biogenesis from the cells, dependently on T-cadherin, but not on AdipoR1 or AdipoR2. Such enhancement of exosome release accompanied the reduction of cellular ceramides through ceramide efflux in exosomes. Consistently, the ceramide reduction by adiponectin was found in aortas of WT mice treated with angiotensin II, but not in T-cadherin–knockout mice. Our findings provide insights into adiponectin/T-cadherin–mediated organ protection through exosome biogenesis and secretion.

Significance: Sensing tissue damage is a crucial function of pattern recognition receptors (PRRs). However, endogenous ligand recognition by PRRs is not well documented. Macrophage inducible C-type lectin (Mincle) is a PRR that recognizes both pathogens and damaged cells. In this study, we isolated endogenous glycolipids derived from damaged cells and identified a ubiquitous intracellular metabolite, β-glucosylceramide (GlcCer), as a Mincle ligand. β-GlcCer induced inflammatory and acquired immune responses via Mincle on myeloid cells. Accumulation of β-GlcCer leads to Gaucher disease, a disorder characterized mainly by systemic inflammation. In a Gaucher model in which mice are deficient in the β-GlcCer–degrading enzyme, further deletion of the Mincle gene attenuated inflammatory responses. These results suggest that β-GlcCer is an endogenous Mincle ligand and acts as an immunostimulatory factor upon cell damage.

Lipidomics, the mass spectrometry-based comprehensive analysis of lipids, has attracted attention as an analytical approach to provide novel insight into lipid metabolism and to search for biomarkers. However, an ideal method for both comprehensive and quantitative analysis of lipids has not been fully developed. Herein, we have proposed a practical methodology for widely-targeted quantitative lipidome analysis using supercritical fluid chromatography fast-scanning triple-quadrupole mass spectrometry (SFC/QqQMS) and theoretically calculated a comprehensive lipid multiple reaction monitoring (MRM) library. Lipid classes can be separated by SFC with a normal phase diethylamine-bonded silica column with high-resolution, high-throughput, and good repeatability. Structural isomers of phospholipids can be monitored by mass spectrometric separation with fatty acyl-based MRM transitions. SFC/QqQMS analysis with an internal standard-dilution method offers quantitative information for both lipid class and individual lipid molecular species in the same lipid class. Additionally, data acquired using this method has advantages including reduction of misidentification and acceleration of data analysis. Using the SFC/QqQMS system, alteration of plasma lipid levels in myocardial infarction-prone rabbits to the supplementation of eicosapentaenoic acid was first observed. Our developed SFC/QqQMS method represents a potentially useful tool for in-depth studies focused on complex lipid metabolism and biomarker discovery.

Recently, we identified a novel mechanism of lipotoxicity in the kidney proximal tubular cells (PTECs); lipid overload stimulates macroautophagy/autophagy for the renovation of plasma and organelle...