Crohn Disease : from gene to therapy

Prof Jean-Pierre HugotHopital Robert Debré

Paris, FranceJean-pierre.hugot@rdb.aphp.fr

Gordon Oppenheimer, Burill B Crohn and Leon Ginzburg, 1969

From « BB Crohn, Life and Work », Falk Foundation 2000

Treatments for Crohn Disease• Antibiotics• Probiotics• Nutritional support• 5 amino-salicylates• Steroids

• Immunosupressive drugs• Antibodies against TNF

and other chemiokines (IL12, ICAM, 4integrins)

• Pig parasites

Trichuris SuisTrichuris Suis

Environnemental factor

Genetic factor

Bouma G et al. Nature Rev Immunol 2003

1 2 3 4 5 6 7 8 9 10 11 12

13 14 15 16 17 18 19 20 21 22 Y X

IBD loci

IBD7IBD3

IBD2

IBD4 IBD8

SLC22A4/5

IBD6

DLG5

CARD15

Ibd1-Nod2-Card15

LRRTM ?NBDCARD 1 CARD 2

1 121 129 217 270 299 570 744 1020 1040

N ter C ter

NF-kBActivation

Oligomerisation Bacterial recognition

Why to discover genes?

• To make a diagnosis • Before disease occurrence (if prevention

possible) or to avoid invasive procedures (sensibiility, sensitivity).

Proportion of mutated patients (all non conservative variations *)

0%10%20%30%40%50%60%70%80%90%

100%

CD (n=453) UC (n=159) controls (n=103)

2 mutations1 mutation0 mutation

*except P268S

Why to discover genes?

• To make a diagnosis • Before disease occurrence (if prevention possible) or to

avoid invasive procedures (sensibiility, sensitivity).

• To classify the disease (definition of disease subgoups)

NOD2/CARD15 mutations are associated with :

• A younger age of onset

• A more frequent ileal involvement

• An higher complication rate• Lesage et al. Am J Hum Genet 2002• Vermeire et al. Am J Hum Genet 2002• Cuthbert et al. Gastroenterology 2002

• Hampe et al. Lancet 2002• Amhad et al. Gastroenterology 2002• Abreu et al. Gastroenterology 2002• Louis E et al. Gut 2003

Why to discover genes?

• To make a diagnosis • Before disease occurrence (if prevention possible) or to

avoid invasive procedures (sensibiility, sensitivity).• To classify the disease (definition of disease subgoups)

• To develop a treatment• Gene therapy (in the future?)

• Pharmacogenetics

Genotype/phenotype relationship : response to Infliximab.

0

10

20

30

40

50

60

%

CompleteResponse(n=132)

Partialresponse(n=58)

No Response(n=55)

wild type

heterozygous

homozygous andcompoundheterozygous

Vermeire S et al. Gastroenterology in press

Why to discover genes?

• To make a diagnosis • Before disease occurrence (if prevention possible) or to

avoid invasive procedures (sensibiility, sensitivity).• To classify the disease (definition of disease subgoups)

• To develop a treatment• Gene therapy (in the future?)• Pharmacogenetics

• Drug discovery (disease mechanisms)

From Elson C.N Eng J Med 2002

From Ogura et al. Nature 2001

..can induce an inflammation?

How a defect in a proinflammatory molecule…

CARD15 -/- mouse

Pauleau AL et al. Mol Cel Biol 2003

+/+

-/-

Watanabe T Nat Immunol 2004

Interaction between TLR2 and NOD2

How CD mutations induce the inflammation?

• A defect in the innate immunity induces an excess of response by the adaptive immunity which is deleterious for the mucosa.

• CD mutations are gain of fonction mutations (Maeda S Science 2005)

• CD mutations do not inhibit pro-inflammatoy pathways (Watanabe T Nature Immunol 2004; Chen CM J Biol Chem 2004)

• CD mutations no more activate anti-inflammatory pathways (IL10) (Netea MG Eur J Immunol 2004)

Unpublished 

CARD15 immunohistochemistrynormal colon Crohn

Berrebi D et al. Gut 2003

Card15 immunohistochemistry

Berrebi D et al. Gut 2003

NOD2 and Paneth cells

Ogura Y et al. Gut 2003

Crohn normal ileum

Card15

Lysozyme

Screening for Card15/Nod2 interacting small molecules

• Loss or gain of function?

• Which cell line?

• Role of MDP?

Toward a specific curative thérapy?

Why to discover genes?

• To make a diagnosis • Before disease occurrence (if prevention possible) or to

avoid invasive procedures (sensibiility, sensitivity).• To classify the disease (definition of disease subgoups)

• To develop a treatment• Gene therapy (in the future?)• Pharmacogenetics• Drug discovery (disease mechanisms)

• Prevention (environmental factors)

From Rose J et al. Gut 1988

ENVIRONMENTAL FACTORS FOR CD• Tobacco• Refined sugars• Fast-food and Cola• Microparticles• Tooth paste• Chewing-Gum• Margarin• Fibres• Backer yeast• Alcohol• Caffe• Corn-flakes• Curry

• Hot water• Refrigeration• Perinatal Infections• Infections in childhood • Antibiotics• Adenoïdectomy • Breast feeding• Life events• Oral contraceptives

Commensal flora….

Or specific pathogenic bacteria ?

Most popular infectious agents for CD

• Mycobacterium paratuberculosis

• E coli, • Y enterocolitica • L monocytogenes• Pseudomonas species

Card15Specific bacteria?

Octn 1/2?

Dlg5? Flora?way of life