TL1A Expression in Human IBD and Animal

ModelsBala Manickam

Pfizer ACVP-STP fellow, Anatomic pathology residentUniversity of Georgia, Athens GA

TL1A & DR3 - Biology

Nat Rev Rheumatol. 2010 Feb;6(2):67-82

Biochem Pharmacol. 2011 Apr 1;81(7):838-47

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Inflammatory Bowel Disease

Human IBD

IBD represents an important chronic disease affecting the GI tract of man and domesticated animal species.

The 2 IBD entities in humans are Crohn’s disease (CD) and Ulcerative colitis (UC).

Immune mediated - responds to immunomodulatory drugs

The pathogenesis of IBD involves:1. Failure of immune regulation.2. Genetic susceptibility.3. Environmental triggers

(microbial flora).4. Disruption of the mucosal

barrier.

Mouse models of IBD

DSS (Dextran sulphate) colitis: Oral administration of this sulphated polysaccharide to mice induces a self limiting colitis

TNBS (Trinitrobenzene sufonic acid) colitis: Colonic inflammation is induced by intrarectal administration of TNBS dissolved in 50% ethanol

Canine IBD

Small intestine: Lymphocytic-plasmacytic enteritis (LPE), eosinophilic enteritis and eosinophilic gastro-enteritis (EGE)

Large intestine; Lymphocytic-plasmacytic colitis, eosinophilic colitis, histiocytic ulcerative colitis (HUC) (mainly PAS-positive macrophages), and regional granulomatous colitis (mainly PAS-negative macrophages)

Healthy Person CD UC

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TL1A & DR3 expression in human IBD

TL1A

DR3

J Immunol 2003;171;4868-4874

Control anti TL1A

Mucosal Immunology (2011) 4, 172-185;

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TL1A & DR3 : Evidence of Efficacy

TNBS colitis

DSS colitis

Control DR3 KO

Gut bacteria Gut bacteria

GASTROENTEROLOGY 2008;135:552–567

Rationale for current study

Up-regulation of TL1A and DR3 in human CD and UC and in rodent IBD models

TL1A and DR3 deficiency attenuates murine IBD

IBD occurs spontaneously in dogs. Because of this, and because it shares a similar immunopathology, it may provide valuable mechanistic insight into the disease in humans.

Studying IBD in spontaneous and induced models may provide insights into how we model the disease in laboratory mice

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Hypothesis

By characterizing and comparing expression profile of TL1A and other critical immunological markers in murine IBD to people, we may further validate (and perhaps even uncover) therapeutic targets for human IBD.

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Objectives

Compare and characterize the staining of TL1A & DR3 in intestinal tissues obtained from DSS and TNBS mouse colitis models, human IBD, canine IBD and normal colons from cynomolgus monkeys.

Compare the staining characteristics of mast cells in intestinal tissues obtained from DSS and TNBS mouse colitis models, human IBD and canine IBD.

Compare the expression of T&B cells in different models of IBD.

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Experimental design Groups Number of

subjectsNumber of slides/subject

Total number of slides

DSS (Mouse) 5 10 50

TNBS (Mouse) 5 10 50

Normal colon (Mouse) 5 10 50

UC (Human) 6 6 36

CD (Human) 6 6 36

Normal colon (Human) 6 6 36

Normal colon (Primate) 5 5 25

IBD (Dog) 5 10 50

Normal colon (Dog) 5 10 50

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Reagents

• Anti-human TL1A mAb (made by Pfizer, optimized for IHC)– Homology to mouse, rat: 92%– Homology to dog (predicted): 86%

• Anti-human DR3 mAb (made by Novus Biol)– The immunogenic peptide shares– 44% homology with canine DR3 (XP_546752 )– 88% homology with primate DR3 (XM_003274297

• CD3, CD45RB220, CD20, Toluidine blue

Pfizer Internal Use 10

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Normal CD UC

Results: TL1A expression

Mice

Naïve DSS TNBS

Human

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Cynomolgus Human Mice

Vasculature(+)

Results: TL1A expression

Germinal center

(-)

DR3 CD Lamina propria

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Mast cells in IBD – Dog, Mice

H&E

Naive IBD

T-blue

Naive DSS TNBS

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B-lymphocytes-Human IBD

Germinal center

Normal CD UC

Lamina propria

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B-lymphocytes-Mice IBD

Germinal center

Naive DSS TNBS

Lamina propria

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T-lymphocytes-Human IBD

Germinal center

Normal CD UC

Lamina propria

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T-lymphocytes-Mice IBD

Germinal center

Naive DSS TNBS

Lamina propria

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B & T lymphocytes- Cynomolgus

Germinal center

B-cells T-cells

Lamina propria

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TL1A: The expression of TL1A was similar and consistent across the species TL1A was up regulated in IBD when compared to the Naive/healthy patients This data not only validates the existing murine IBD models but also indicates

that TL1A could be a druggable target in IBD We also uncovered that Cynomolgus shares similar staining characteristics

with human and murine IBD tissues and thus can probably be a good model to study human IBD

B&T-lymphocytes: Increased numbers of both B & T cells in the lamina propria in cases of IBD,

suggests a potential role for immune activation in IBD

Mast cells: In our study, We could not detect any difference in the expression of mast

cells in both naïve and or IBD patients in both murine and Dog cases.

Conclusion

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Acknowledgement

Dr. Timothy LaBranche (Industry Mentor) Dr. Elizabeth Howerth (Academic Mentor) Dr. Zaher Radi (Pfizer) Dr. Shawn O’ Neil (Pfizer) Jameel Syed (Pfizer) Zachery Stewart (Pfizer) University of Georgia ACVP-STP Coalition Studies were funded and supported by DRSD, Pfizer

Pfizer Internal Use 21

Thank you!