Gene-Environment Interplay on Behaviour

1. Gene-Environment Interplay on Behaviour Marla B. Sokolowski, PhD, FRSC University Professor Canada Research Chair in Genetics and Behavioural Neurology, Academic Director Institute for the Fraser Mustard Human Development. Co-director of Canadian Institutes for Advanced Research (CIFAR) Experience Based Brain and Biological Development Programme (EBBD),

2. Funding for our Research

3. Early adversity sets developmental trajectories for health, learning and social functioning across the life-time. How? a) Gene-Environment Interactions b) Epigenetics

4. For most traits: • It’s not just nature (genes) • It’s not just nurture (environment) • It’s not nature plus nature (genes + environment). It is their interaction! G x E Sokolowski and Wahlsten 2001

5. Example of Gene by Environment Interaction in Human Mothering Behavior (serotonin transporter gene variants LL, SS and LS) Mileva-Seitz et al 2011

6. Why? Conservation of DNA Sequence Conservation of a Gene’s Behavioural Function Candidate Genes Model Organisms to Humans

7. Example 2: G x E: The foraging(for) gene • Almost all organisms have the gene including humans! • The gene affects energy balance: food intake, food related movement, fat, learning and memory • Different individuals have different forms of the gene –rover or sitter • The gene makes an enzyme found in the brain called PKG. Rovers have more of it than sitters • How much enzyme the gene makes depends on the environment. (G x E) (Osborne et al 1997 Science; Ben Shahar et al 2002 Science; Mery et al 2007 PNAS; Fitzpatrick et al 2007 Nature; Kaun et al 2007 J Exp Biol; Lucas and Sokolowski 2009 PNAS; Sokolowski 2010 Neuron).

8. Rover and sitter foraging behaviour Sokolowski 2001 Nature Review Genetics

9. The rover/sitter natural variants are due to variation in a single gene called foraging which makes a cGMP-dependent protein kinase (PKG) enzymeRover heads and larval CNSs have more foraging enzyme than sitter heads and larval CNSs. Osborne et al. 1997 Science 277: 834-836.

10. Proof of cloning the DNA of the foraging gene: “Gene Therapy”

13. The foraging gene responds to the environment Fruit Flies Honey Bee Nurse or forager Rover or sitter BenShahar et al 2002 Science Osborne et al 1997 Science Nematode Worm Ant Roamer or dweller Forager or defender Fujiwara et al. 2002 Neuron Lucas & Sokolowski 2009 PNAS Sokolowski 2010 Neuron

14. Gene-Environment Interaction in response to the nutritional environment

15. Rover Rover Sitter Sitter Enzyme Activity 15 12 Food Intake 10 8 * 5 4 100% 15% 100% 15% Food Quality Food Quality Example 2: Rovers change into sitters when chronically food deprived (the gene is responsive to the early rearing environment) Kaun et al 2007 J Exp Biol

16. Chronic nutritional deprivation in the larval period affects adult exploratory behaviour Burns et al 2012 PNAS

17. Darting Exploration (darting is stop and go motion) High ‘darting exploration’ Low ‘darting exploration’

18. G-E interplay: sitter adults exhibit a more plastic response to modifications in the larval nutritional environment *** *** p<0.001 Burns et 2012 PNS

19. Cost of darting exploration Dworkin, Michigan State www.chickencrap.com

20. Increasing foraging gene expression in the mushroom bodies changes exploratory behavior from sitter to rover (reared in 100% food) *** UAS-forT1a + - + - + - - Gal4 30Y 201Y 739Y None *** p<0.001, ** p<0.01, * p<0.05 Burnset al 2012 PNAS

21. Chronic food deprivation early in life effects adult fitness (fecundity) Burns et al 2012 PNAS

22. foraging affects learning and memory: the gene is responsive to the environment Rovers have better short term memory. foraging acts in the mushroom bodies for olfactory based aversive learning and memory Mery et al 2007 PNAS

24. Example 3: Gene-Environment interplay in response to social context

25. STM: sitters are sensitive to the learning context (rovers and sitters are trained alone or in groups) P = 0.20 P = 0.005 Kohn, Reaume, Burns, Sokolowski, Mery(submitted)

26. Increasing foraging enables sitter to learn when alone PKG activator (8-Bromo-cGMP) on flies trained and tested alone P = 0.01 P < 0.001 S2 Treatment

27. Decreasing PKG decreases learning in rovers PKG inhibitor (KT5823) on individuals trained and tested alone P = 0.01 S2 Treatment

28. Early adversity sets developmental trajectories for health and behaviour across the life-time. How? a) Gene-Environment Interactions b) Epigenetics

29. DNA is like books in a library. Limitless potential to inform and inspire…….But they need to be read.

30. Health Risks Depression Drug abuse Anxiety Diabetes Heart disease Obesity Early Experience Abuse Family strife Emotional neglect Harsh discipline Health Risks Associated with Early Adversity and Low SES Individual differences in neural and endocrine responses to stress brain development, Immune system Prevention

31. A New Science = EPIGENETICS the study of those environmental factors that alter whether DNA will be “expressed” without altering the DNA sequence Epigenetics Factors that change the likelihood that a book will be read. Champagne and Mashoodh, 2009

32. What factors induce epigenetic changes? Epigenetic Variation nutrition stress Environmental toxins hormones drug use social interactions smoking

33. When the DNA is read it is said to be “expressed” hard to read epigenetics easier to read Early adversity makes some genes difficult to read. Those involved in: 1) how we cope with stress, 2) how our brain develops and works and, 3) how we fight disease.

34. Social Interactions: Natural Variations in Maternal Care in the Rat: High and Low Lickers and Groomers. Differential Methylation of Glucocorticoid Receptor in rats (and humans) Michael Meaney, McGill University

35. Low licking and grooming High licking and grooming Cross fostering

36. 0.8 0.6 0.4 0.2 0.0 Epigenetics: Cross-fostering shows direct effects of maternal care on the expression of genes in the brain (i.e. glucocorticoid receptor) involved with coping with stress! * * GRir (ROD) High/High High/Low Low/High Low/Low Biological Mom / Foster Mom Gl

37. 60 1.5 1.0 40 0.5 20 0.0 0 Control Control Suicide Suicide - Abuse + Abuse Suicide Suicide - Abuse + Abuse Early Abuse in Victims of Suicide * GR 1-F CpGMethylation (%) * GR-1F mRNA/GAPDH (log conc.) McGowan et al 2009 Nature Neuroscience

38. Changes to the epigenome are a cellular memory of an environmental event New Era of Research on the Origins of our “Uniqueness”

39. Consequences? • The mom’s behaviour (social context) affects the lifelong health of the infants via later stress reactivity • The mom’s behaviour is transferred to the pups in an epigenetic manner • Is this epigenetic effect is reversible, how?

40. Early adversity sets developmental trajectories for health and behaviour across the life-time. How: mechanisms? Gene by Environment Interaction and Epigenetics When: sensitive periods? What: early adversities? (individual differences)

41. Drosophila foraging gene project: Amsale Belay Ralph Greenspan Kate Osborne Joel Levine Mark Fitzpatrick Chris Reaume Locke Rowe Tony So Karla Kaun Tad Kawecki Craig Riedl Bertam Gerber Clement Kent Thomas Hendel Bryon Hughson Aaron Allen Hiwote Belay Bee foraging gene project: Yehuda Ben-Shahar Alain Robichon Gene Robinson Ant foraging gene project: Christophe Lucas Human foraging gene project James Kennedy Robert LevitanHiwote Belay Sam Bidnur Roger Ferreira Torry Higgins Learning and Memory Fred Mery Nancy Kohn

42. Epigenetic by Genetic Interactions

43. How does the foraging gene respond to food deprivation? Hypothesis: Epigenetic modification of foraging by EHMT euchromatinhistonemethyltransferases a family of evolutionarily conserved proteins that write part of the epigenetic code through methylation of histone 3 at lysine 9 (H3K9). EHMT is a a key epigenetic regulator of neuronal genes and processes.

44. EHMT in the transcriptional control of foraging (Mutations in EHMT affect larval foraging behaviour and adult cognition) foraging gene transcripts Loss of methylation peak in EHMT mutants USCS genome browser “LOMB” track Kramer et al in prep

45. FORAGING protein levels are reduced in response to food deprivation. This does not occur in EHMT mutants EHMT(-) Kramer et al in prep

46. I. Anreiter, J. Kramer, M.B. Sokolowski

47. I. Anreiter, B. Hughson, J. Kramer, M.B. Sokolowski

48. foraging’s behavioural plasticity may be regulated via epigenetic modifications through EHMT. -foraging allele specific? -food deprivation specific? -other organisms? bees, ants, flies, humans?