The Role of Twin Studies in IBD Research

Dr Hannah GordonClinical Research Fellow

Chelsea and Westminster Hospital

Introduction

• Review • History of twin studies• Twin studies in IBD• New molecular techniques in IBD

• UK IBD Nixon Twin and Multiplex Registry and Biobank

History of Twin Studies

• 1st recorded 1875 • Francis Galton (1)• Description of twin pairs

• Personal traits• Physical and mental health

“Nature is far stronger than nurture”

• Monozygotic vs dizygotic distinguished 1914 (2)

Twin Studies – study design

• Classical• Monozygotic vs dizygotic (nature vs nurture)

• Adoption• Genetically identical individuals reared apart

• Longitudinal• Correlation between environment and discordance

over time • Exercise and depression

• Offspring of twins• Birth weight of children of MZ female twins more

similar than birth weight of children of MZ male twins

Twin Studies in IBD – Inheritance

• Twin study 1988 showed CD MZ concordance 55% DZ concordance 3.8% (3)• Figure 1: Range of Concordance of Crohn’s and UC between Twin Pairs (from Swedish, UK, Danish, Dutch and German Twin Populations (4))

• Variation• CC defined 1960s• Genetic differences between populations

• Crohn’s has stronger genetic basis

• Strong environmental component

Crohn’s Disease Ulcerative Colitis

Monozygotic 20-55% 6.3-17%

Dizygotic 0-3.6% 0-6.3%

Twin studies:

• UC altered mucosal glycosylation presented in discordant MZ pairs (9)

• MZ concordance • CD location and behaviour• UC extent (5,6)

• monozygotic twin pairs x1CD x1 UC (7)

• X2 concordance DZ twins compared with other siblings (8)• Shared uterus• More similar childhood environment

Genome Wide Association Studies

• 163 SNPs associated with IBD (10,11)

The Microbiome – a living active ecosystem

• Trillions of microbes (10x number of human cells) (12)• >1000 species level phylotypes• Microbial genome 150x larger than human host (13)• Changes during life• Interactions with host (and each other)

• Obesity• DM• IBD• CV disease

Study of Microbiota

• Megagenomics • 16srRNA PCR sequencing and amplification (14)

• Metaproteomics • Expressed gene products

• Metabolomics• Metabolites of host-microbiota interactions• High res NMR spect• Multivariate statistical analysis• “Metabolic fingerprint”

Microbiota of MZ twins:

• Healthy MZ twins have similar microbiota (15)

• Twins with CD have differing microbiota (concordant or discordant) (16)

• Microbiota tends towards phenotype rather than genotype (17)

• Inactive UC microbiota no different from healthy twin (18)

Metabolomics – “Fingerprints” in IBD

• Metabolomic profile of faecal water of A) CD (n=10), B) UC (n=10), C) Healthy control (n=13) (19)

Key:

1, butyrate; 2, leucine; 3, propionate; 4, valine; 5, isoleucine; 6, threonine; 7, alanine; 8, lysine; 9, acetate; 10, glutamate; 11,succinate; 12, aspartic acid; 13, asparagine; 14, trimethylamine; 15, cysteine; 16, proline; 17, glycerol; 18, methylamine; 19, 5-aminosalicylicacid; 20,N-acetyl-5-aminosalicylic acid; 21, tyrosine; and 22, uracil

Metabolomic profiles IBD:

• CD• Depletion of short chain fatty acids• Decreased methylamine and trimethylamine

• UC• Increased amino acids

Metabolomic profiles of Twins

• Difference between discordant MZ pairs (ICD and CCD) (20)

• Similarity between healthy MZ• Differentiation between ICD and CCD

• ?Metabolites associated with SNPs higher in affected twin

Epigenetics – Blurring the distinction between nature and nurture

• “Heritable changes in gene expression that occur without alterations in DNA sequence” (11)

• Methylation • gene silencing

• Histone modification

• Changes persist after mitosis• ?persist after meiosis (transgenerational)

Epigenetics

• IBD – 50 genes with different methylation between patients with CD and controls (21)

• Twin studies – different methylation patterns SLE MZ discordant

• Role of twin studies• ?timing of methylation• ?Inheritance of methylation in offspring

MicroRNA

• Small non coding RNA molecule• Transported from nucleus• Forms protein complex• Binds with mRNA• mRNA degraded sooner and translated less

• How does it change in IBD?• Distinct miRNA signatures in peripheral blood in CD

vs UC vs Control (11)• MiRNA

• NOD2 controls miRNA expression (24)• MiRNA 29 deficient mice – worse colitis

Limitations of twin studies

• Sample size

• MZ twins 3/1000 births• DZ twins 13/1000 births• IBD prevalence UK 400/100,000

IBD Nixon TAM Registry and Biobank

• History• Royal Free Dataset

• 250 twin pairs

• Study of MZ vs DZ concordance 1996 (23)• Database revisited and reanalysed 2011 (6)

• Concordance of disease location and extent• Childhood infection

• Current• Contacting Twins from previous dataset• Recruiting new Twin pairs• Biobank

Conclusion

• Continuing relevance to twin studies in omics era(2)• Microbiome• Epigenetics

• Twin studies to date• Evidence of genetic component

• Development• Disease pattern

• Galton wrong – environmental factors predominate

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smoking. Gut. 1988; 29: 990–9964. Brant S. Update on the heritability of IBD: The importance of twin studies. Inflammatory Bowel Disease Vol 17, Issue 1, Pg 1-5 Jan 20115. Halfvarson J, Jess T, Bodin L, et al. Longitudinal concordance for clinical characteristics in a Swedish-Danish twin population with inflammatory bowel disease. Inflamm Bowel Dis. 2007; 13:

1536–1544.6. Ng SC, Woodrow S, Patel N, Subhani J, Harbord M. Role of genetic and environmental factors in British twins with Inflamatory Bowel disease. Inflamm Bowel Dis. 2012 Apr;18(4):725-36. doi:

10.1002/ibd.21747. Halfvarson J. Genetics in twins with Crohn's disease: less pronounced than previously believed? Inflamm Bowel Dis. Epub ahead of print: 2010; June8. Bengtson MB, Aamodt G, Vatn MH, Harris JR. Concordance for IBD among twins compared to ordinary siblings – a Nowegian population based study. J Crohns Colitis. 2010 Sep;4(3):312-8 9. Bodger K, Halfvarson J, Dodson AR, Campbell F, Wilson S, Lee R, Lindberg E, Järnerot G, Tysk C, Rhodes JM. Altered colonic glycoprotein expression in unaffected monozygotic twins of

inflammatory bowel disease patients. Gut. 2006 Jul;55(7):973-7. Epub 2006 Feb 410. Jostins L, Ripke S, Weersma RK, et al. Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease. Nature. 2012;490:119–12411. Ventham NT, Kennedy NA, Nimmo ER, Satsangi J. Beyond gene discovery in inflammatory bowel disease: the emerging role of epigenetics. Gastroenterology.2013 Aug;145(2):293-30812. Nicholson JK, Holmes E, Kinross J, Burcelin R, Gibson G, Jia W, Pettersson S. Host-gut microbiota metabolic interatctions. Science. 2012 Jun 8;336(6086):1262-713. Qin, J., Li, R., Raes, J., Arumugam, M., Burgdorf, K.S., Manichanh, C., Nielsen, T., Pons, N., Levenez, F., and Yamada, T., et al A human gut microbial gene catalogue established by

metagemonic sequencing .MetaHIT Consortium Nature 464, 59-65(2010) 14. Holmes E, Li JV, Marchesi JR, Nicholson JK. Gut microbiota composition and activity in relation to host metabolic phenotype and disease risk. Cell Metab. 2012;16(5):559-64.15. Dicksved J, Halfvarson J, Rosenquist M, Jarnerot G, Tysk C, et al. (2008) Molecular analysis of the gut microbiota of identical twins with Crohn's disease. ISME Journal 2: 716–72716. Erickson AR, Cantarel BL, Lamdela R, Darzi Y, Mongeodin EF, Pan C, Shah M, Halvarson J, Tysk C, Henrissat B, Rees J, Verberkmoes NC, Fraser CM, Hettich RL, Jannson JK. Integrated

metagenomics/metaproteomics reveals human host-microbiota signatures of Crohn’s disease. 2012;7(11):e49138. doi: 10.1371/journal.pone.0049138. Epub 2012 Nov 28.17. Willing B, Halfvarson J, Dicksved J, et al. Twin studies reveal specific imbalances in the mucosa-associated microbiota of patients with ileal Crohn's disease. Inflamm Bowel Dis. 2009; 15:

653–66018. Willing BP, Dicksved J, Halfvarson J, Andersson AF, Lucio M, et al. (2010) A pyrosequencing study in twins shows that gastrointestinal microbial profiles vary with inflammatory bowel disease

phenotypes. Gastroenterology 139: 1844–185419. Marchesi RJ, Holmes E, Khan F, Kochhar S, Scanlan P, Shanahan F, Willson ID, Wang Y. Rapid and noninvesive metabolomics characterization of inflammatory bowel disease. J. Proteome Res

2007 Feb;6(2):546-51.20. Jansson J, Willing B, Lucio M, Fekete A, Dicksved J, et al. (2009) Metabolomics Reveals Metabolic Biomarkers of Crohn's Disease. PLoS One 4: e368621. Nimmo ER, Prendergast JG, Aldhous MC, et al. Genome-wide methylation profiling in Crohn’s disease identifies altered epigenetic regulation of key host defense mechanisms including the

Th17 pathway. Inflamm Bowel Dis. 2012;18:889–89922. Wu F, Guo NJ, Tian H, et al. Peripheral blood microRNAs distinguish active ulcerative colitis and Crohn’s disease. Inflamm Bowel Dis. 2012;17:241–25023. Thompson N, Driscoll R, Pounder R E, Wakefield A J. Genetics versus environment in inflammatory bowel disease: results of a British twin study. BMJ. 1996 January 13; 312(7023): 95–9624. Brain O, Owen B et al. The intracellular sensor NOD2 Induces MicroRNA-29 Expression In Human Dendritic Cells to limit IL23 release. Immunity 39 521–536, September 19, 2013

Inflammatory Bowel Diseases 2014

• Bella Center Copenhagen, Denmark• EACCME applied• Register online at www.ecco-ibd.eu

CALLING ALL TWINS!!!!!

If you know of any IBD patients who are part of a twin pair please contact me:

Email: hannah.gordon@chelwest.nhs.ukTel: +44 (0)7834 705791