title: Metabolic determinants of the immune modulatory function of neural stem cells.
abstract: Neural stem cells (NSCs) display tissue trophic and immune modulatory therapeutic activities after transplantation in central nervous system disorders. The intercellular interplay between stem cells and target immune cells is increased in NSCs exposed to inflammatory cues. Here, we hypothesize that inflammatory cytokine signalling leads to metabolic reprogramming of NSCs regulating some of their immune modulatory effects.
  
  
  
  NSC lines were prepared from the subventricular zone (SVZ) of 7-12-week-old mice. Whole secretome-based screening and analysis of intracellular small metabolites was performed in NSCs exposed to cocktails of either Th1-like (IFN-γ, 500 U/ml; TNF-α, 200 U/ml; IL-1β, 100 U/ml) or Th2-like (IL-4, IL-5 and IL-13; 10 ng/ml) inflammatory cytokines for 16 h in vitro. Isotopologues distribution of arginine and downstream metabolites was assessed by liquid chromatography/mass spectrometry in NSCs incubated with U-(13)C6 L-arginine in the presence or absence of Th1 or Th2 cocktails (Th1 NSCs or Th2 NSCs). The expression of arginase I and II was investigated in vitro in Th1 NSCs and Th2 NSCs and in vivo in the SVZ of mice with experimental autoimmune encephalomyelitis, as prototypical model of Th1 cell-driven brain inflammatory disease. The effects of the inflammatory cytokine signalling were studied in NSC-lymph node cells (LNC) co-cultures by flow cytometry-based analysis of cell proliferation following pan-arginase inhibition with N(ω)-hydroxy-nor-arginine (nor-NOHA).
  
  
  
  Cytokine-primed NSCs showed significantly higher anti-proliferative effect in co-cultures vs. control NSCs. Metabolomic analysis of intracellular metabolites revealed alteration of arginine metabolism and increased extracellular arginase I activity in cytokine-primed NSCs. Arginase inhibition by nor-NOHA partly rescued the anti-proliferative effects of cytokine-primed NSCs.
  
  
  
  Our work underlines the use of metabolic profiling as hypothesis-generating tools that helps unravelling how stem cell-mediated mechanisms of tissue restoration become affected by local inflammatory responses. Among different therapeutic candidates, we identify arginase signalling as novel metabolic determinant of the NSC-to-immune system communication.
authors: CNS Repair Unit, Institute of Experimental Neurology (INSPE), Division of Neurosciences, San Raffaele Scientific Institute, 20132, Milan, Italy. drago.denise@hsr.it.|Department of Clinical Neurosciences, Wellcome Trust-Medical Research Council Stem Cell Institute and National Institute for Health Research Biomedical Research Centre, University of Cambridge, Hills Road, CB2 0HA, Cambridge, UK. drago.denise@hsr.it.
authors: Denise
authors: D
authors: Drago
authors: Lymphocyte Activation Unit, San Raffaele Scientific Institute, 20132, Milan, Italy.
authors: Veronica
authors: V
authors: Basso
authors: Medical Research Council Cancer Unit, Hutchison/MRC Research Centre, Cambridge, CB2 0XZ, UK.
authors: Edoardo
authors: E
authors: Gaude
authors: Department of Clinical Neurosciences, Wellcome Trust-Medical Research Council Stem Cell Institute and National Institute for Health Research Biomedical Research Centre, University of Cambridge, Hills Road, CB2 0HA, Cambridge, UK.
authors: Giulio
authors: G
authors: Volpe
authors: Department of Clinical Neurosciences, Wellcome Trust-Medical Research Council Stem Cell Institute and National Institute for Health Research Biomedical Research Centre, University of Cambridge, Hills Road, CB2 0HA, Cambridge, UK.
authors: Luca
authors: L
authors: Peruzzotti-Jametti
authors: Biomolecular Mass Spectrometry Unit, Division of Genetics and Cell Biology, San Raffaele Scientific Institute, 20132, Milan, Italy.
authors: Angela
authors: A
authors: Bachi
authors: Biomolecular NMR Unit, San Raffaele Scientific Institute, 20132, Milan, Italy.
authors: Giovanna
authors: G
authors: Musco
authors: ProMiFa, Protein Microsequencing Facility, San Raffaele Scientific Institute, 20132, Milan, Italy.
authors: Annapaola
authors: A
authors: Andolfo
authors: Medical Research Council Cancer Unit, Hutchison/MRC Research Centre, Cambridge, CB2 0XZ, UK.
authors: Christian
authors: C
authors: Frezza
authors: Lymphocyte Activation Unit, San Raffaele Scientific Institute, 20132, Milan, Italy.
authors: Anna
authors: A
authors: Mondino
authors: Department of Clinical Neurosciences, Wellcome Trust-Medical Research Council Stem Cell Institute and National Institute for Health Research Biomedical Research Centre, University of Cambridge, Hills Road, CB2 0HA, Cambridge, UK. spp24@cam.ac.uk.
authors: Stefano
authors: S
authors: Pluchino
mesh_terms: D000818:Animals; D001119:Arginase / Q000378:metabolism; D001120:Arginine / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D003124:Colorimetry; D016207:Cytokines / Q000378:metabolism* / Q000494:pharmacology; D004195:Disease Models, Animal; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000378:metabolism / Q000473:pathology; D005260:Female; D007155:Immunologic Factors / Q000378:metabolism*; D020547:Lateral Ventricles / Q000166:cytology; D055432:Metabolomics; D051379:Mice; D058953:Neural Stem Cells / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism
chemical_list: D016207:Cytokines; D007155:Immunologic Factors; D001120:Arginine; D001119:Arginase
keywords: Arginase I; Immune modulation; Lymph node cells; Metabolomics; Neural stem cells