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D-Aspartate as a regulator of brain activity - Annabella Di Giorgio

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Watching at the "D" side: D-amino acids and their significance in neurobiology
June 05 -June 09, 2016 – Lake Como School of Advanced Studies

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D-Aspartate as a regulator of brain activity - Annabella Di Giorgio

  1. 1. D-Aspartate as a regulator of brain activity Annabella Di Giorgio,M.D. Ph.D. M.Sc. ab.digiorgio@operapadrepio.it Lake Como School of Advanced Studies, 9 June 2016
  2. 2. Outline D-Asp and brain activity in vivo in humans DDO genetic variationand imaging prefrontalphenotypes IMAGING GENETICS Fundamentals Lessons from the last decade of research
  3. 3. Single Nucleotide Polymorphism (SNP)
  4. 4. Neuropsychopharmacology2000
  5. 5. British Medical Bulletin 2003
  6. 6. Emergent Phenotype Imaging Genetics: the principle The Wisconsin Card Sorting Task cognition Genes: multiple susceptibility alleles each of small effect Cells: multiple subtle abnormalities Systems: response bias to environmental cues Behavior: Complex functional interaction and emergent phenomena
  7. 7. What have we learned in the past ten years?
  8. 8. Imaging Genetics is a robust strategy for identifyinggeneticassociation with brain physiology Geneticassociation in brain and geneticmechanism ofclinical association are not necessarilyrelated The biology of imagingbiomarkers is easily misinterpreted Geneticassociationwith imagingmeasures depends on context Biological processes are not necessarily linear Lessons from the past ten years Source: http://www.imaginggenetics.uci.edu/
  9. 9. Imaging Genetics is a robust strategy for identifyinggeneticassociation with brain physiology Genetic association in brain and genetic mechanism of clinical association are not necessarily related The biology of imagingbiomarkers is easily misinterpreted Geneticassociationwith imagingmeasures depends on context Biological processes are not necessarily linear Lessons from the past ten years Source: http://www.imaginggenetics.uci.edu/
  10. 10. Di Giorgio et al, Psychol Med 2010 Hippocampal (H)-parahippocampal (PH) physiology during memory encoding in schizophrenia N=61, SPM5, p=1X10-6FWE corr Controls (N=33) vs Patients (N=28) Indoor or Outdoor? Recognition Memory- Encoding Hariri et al., J Neurosci 2003
  11. 11. Interaction between COMT Val158Met genotype and PH activity during memory encoding in schizophrenia VV VM MM MM VM VV N=61, SPM5, p=0.05FWE corr Genotype by diagnosis interaction Di Giorgio et al, Psychol Med 2010
  12. 12. Is this a neural system mechanism of the genetic association with schizophrenia?
  13. 13. Genetic association and brain function: some caveats Most genes are likely to influence brain function Genetic association with brain function and neural mechanisms of clinical risk are not necessarily linked This linkage requires demonstrationthat the neural association is with a heritable, susceptibility-related phenotype (i.e. an intermediate phenotype)
  14. 14. -0,1 -0,05 0 0,05 0,1 0,15 Controls (N=54) Siblings (N=15) Patients (N=39) N=108, SPM8, p=1x10-4 FWE corr H-PH physiology during memory encoding in patients with schizophrenia, unaffected siblings and healthy subjects %correctresponses-ENCODING N=108, [F(2,98)=5.97; p=4x10-3 Controls Siblings Patients 88 89 90 91 92 93 94 95 96 97 98 Maineffectofdiagnosis BOLDsignalinrhippocampus (x34,y–34,z-7)(arbitraryunits±SE) Maineffectofdiagnosis BOLDsignalinrparahippocampus (x34,y–28,z-19)(arbitraryunits±SE) Main effect of diagnosis p=0.008 -0,05 0 0,05 0,1 0,15 0,2 0,25 Controls (N=54) Siblings (N=15) Patients (N=39) p=0.02 Di Giorgio et al, Psychol Med 2013
  15. 15. Imaging Genetics is a robust strategy for identifyinggeneticassociation with brain physiology Geneticassociation in brain and geneticmechanism ofclinical association are not necessarilyrelated The biology of imaging biomarkers is easily misinterpreted Geneticassociationwith imagingmeasures depends on context Biological processes are not necessarily linear Lessons from the past ten years
  16. 16. Biological Psychiatry 2013
  17. 17. Imaging Genetics is a robust strategy for identifyinggeneticassociation with brain physiology Geneticassociation in brain and geneticmechanism ofclinical association are not necessarilyrelated The biology of imagingbiomarkers is easily misinterpreted Genetic association with imaging measures depends on context Biological processes are not necessarily linear Lessons from the past ten years
  18. 18. Zhang , Bertolino et al., PNAS 2007 rs1076560 (G/T) N=119:87 GG + 24 GT N=44:22 GG + 22 GT SPM2, pWE =.05 corrected
  19. 19. N=136, SPM5, pFWE=0.05 corected
  20. 20. DRD2 rs1076560 by CHNRA5 rs16969968 interaction on prefrontal physiology at 2-Back N=329, SPM8, pFWE=0.036 p=0.00008 Di Giorgio et al., PONE 2014 DRD2 GT subjects are not GT-like in the context of other variants
  21. 21. Imaging Genetics is a robust strategy for identifyinggeneticassociation with brain physiology Geneticassociation in brain and geneticmechanism ofclinical association are not necessarilyrelated The biology of imagingbiomarkers is easily misinterpreted Geneticassociationwith imagingmeasures depends on context Biological processes are not necessarily linear Lessons from the past ten years
  22. 22. Emergent Phenotype The Wisconsin Card Sorting Task cognition Genes: multiple susceptibility alleles each of small effect Cells: multiple subtle abnormalities Systems: response bias to environmental cues Behavior: Complex functional interaction and emergent phenomena Ten + Years of Imaging Genetics
  23. 23. Ten + Years of Imaging Genetics Franke et al., Hum Genet 2009 genotype intermediate phenotype phenotype
  24. 24. Background D-Aspartate (D-Asp) is an atypical amino acid, especially abundant in the developing mammalian brain, that occurs at high levels during embryonic stages and dramatically decreases during postnatal life, due to the concomitant expression of the catabolic enzyme D-Asp Oxidase (DDO) (D’Aniello et al., 1993). The biological role of D-Asp in the mammalian brain remains largely elusive. It has been demonstrated that D-Asp activates NMDARs by binding to the glutamate site on GluN2 subunits, modulating neurogenesis, synaptic plasticity and memory in rodents (Errico et al., 2012). Moreover, D-Asp levels are reduced in the post-mortem prefrontal cortex (PFC) of patients with schizophrenia, a disorder in which dysregulation of prefrontal glutamateis centrally implicated (Errico et al., 2013).
  25. 25. Aim of the study Aim of the study was to investigatewhether genetic variation of the DDO gene (6q21) affects DDO mRNA expression in prefrontal cortex and, in turn, modulates prefrontal grey matter volume and activity during working memory (WM) processing in healthy subjects. We hypothesized that genetically mediated reduced expression of DDO is mapped on prefrontal phenotypes suggestive of: a) greater prefrontal neuronal plasticity; b) greater activation of prefrontal neuronal networks during WM.
  26. 26.  Data from 268 post mortem brains of nonpsychiatric individuals were analyzed (http://braincloud.jhmi.edu). Association of DDO SNPs (N=92) with DDO mRNA expression was explored (Bonferroni correction). Rs3757351 (C/T) (intronic SNP) was selected for further in vivo analysis with imaging tools.  152 healthy subjects underwent 3T s-MRI to test the association of rs3757351 with prefrontal grey matter (GM) volume as assessed with voxel based morphometry (VBM).  143 healthy subjects underwent 3T BOLD fMRI to test the association of rs3757351 with prefrontal activity during Working Memory (WM) performance (N-Back task). Material and Methods
  27. 27. BrainCloud http://braincloud.jhmi.edu/
  28. 28. BrainCloud: DDO expression in PFC
  29. 29. DDO gene CHROMOSOME 6 (q21) rs3757351 NewNBCI variation viewer Phase 3 May 2013 Location = 110.735.639 Intron variant Alleles = A/G Global MAF = 0.3419
  30. 30.  Data from 268 post mortem brains of nonpsychiatric individuals were analyzed (http://braincloud.jhmi.edu). Association of DDO SNPs (N=92) with DDO mRNA expression was explored (Bonferroni correction). Rs3757351 (C/T) (intronic SNP) was selected for further in vivo analysis with imaging tools.  152 healthy subjects underwent 3T s-MRI to test the association of rs3757351 with prefrontal grey matter (GM) volume as assessed with voxel based morphometry (VBM).  143 healthy subjects underwent 3T BOLD fMRI to test the association of rs3757351 with prefrontal activity during Working Memory (WM) performance (N-Back task). Material and Methods
  31. 31.  Data from 268 post mortem brains of nonpsychiatric individuals were analyzed (http://braincloud.jhmi.edu). Association of DDO SNPs (N=92) with DDO mRNA expression was explored (Bonferroni correction). Rs3757351 (C/T) (intronic SNP) was selected for further in vivo analysis with imaging tools.  152 healthy subjects underwent 3T s-MRI to test the association of rs3757351 with prefrontal grey matter (GM) volume as assessed with voxel based morphometry (VBM).  143 healthy subjects underwent 3T BOLD fMRI to test the association of rs3757351 with prefrontal activity during Working Memory (WM) performance (N-Back task). Material and Methods
  32. 32. fMRI equipment
  33. 33. N-Back Task X X
  34. 34. Normalisation Statistical Parametric Map Image time-series Parameter estimates General Linear ModelRealignment Smoothing Design matrix Anatomical reference Spatial filter Statistical Inference RFT p <0.05 From images to statistics: processing pipelines.
  35. 35. Association of DDO rs3757351 with mRNA expression levels in post-mortem PFC
  36. 36. Association of DDO rs3757351 with prefrontal GM volume N=152, SPM8, pns Cluster ExtendCorrected =0.03
  37. 37. Association of DDO rs3757351 with prefrontal BOLD response during WM N=143, SPM8, pFWE=0.004
  38. 38. Take home messages Neuroimaging-based phenotyping has unique potential to characterize gene effects in brain and to identify genetic mechanisms of disease and of normal human neurobiologic variation. Using the Imaging genetic approach we have demonstrated for the first time that genetic variation affecting D-asp levels modulate prefrontal phenotypes in humans. Relevance of these findings for the pathophysiology of schizophrenia should be further elucidated.
  39. 39. Summary We demonstrated that the C allele of a single nucleotide variation in DDO (rs3757351), which predicts reduced DDO mRNA expression in human post-mortem PFC, is mapped on greater prefrontal grey matter volume and activity during working memory in healthy Caucasian subjects.
  40. 40. Acknowledgements IRCCS “Casa Sollievo della Sofferenza” San Giovanni Rotondo (FG), IT Teresa Popolizio Annalisa Simeone Domenico Di Bisceglie PNG, University of Bari “Aldo Moro”, Bari, IT Alessandro Bertolino Giuseppe Blasi, GraziaCaforio, Ileana Andriola, Linda Antonucci, Maria Teresa Attrotto, AuroraBonvino, Lucia Colagiorgio, Marco Colizzi, Pasquale Di Carlo, Enrico D’Ambrsio, Leonardo Fazio, Barbara Gelao, Riccarda Lomuscio, Giancarlo Maddalena, Marina Mancini, Rita Masellis, Apostolos Papazacharias, Giulio Pergola, Annamaria Porcelli, Tiziana Quarto, Antonio Rampino, Raffaella Romano, Pierluigi Selvaggi, Paolo Taurisano CBDB-NIMH-NIH Bethesda (MD)/Lieber Institute for Brain Development, JohnsHopkins, Baltimore (MD) USA Joseph H Callicott Venkata S Mattay Gianluca Ursini Daniel R. Weinberger Ohio State University, Columbus (OH) USA Ryan M Smith Wolfgang Sadee CEINGE - University of Naples, Naples , IT FrancescoErrico FrancescoNapolitano Alessandro Usiello King’s College London, London, UK Paola Dazzan

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