TL1A Expression in Human IBD and Animal Models BalaManickam Pfizer ACVP-STP fellow, Anatomic pathology resident University of Georgia, Athens GA
TL1A & DR3 - Biology Biochem Pharmacol. 2011 Apr 1;81(7):838-47 Nat Rev Rheumatol. 2010 Feb;6(2):67-8
Inflammatory Bowel Disease • Mouse models of IBD • DSS (Dextran sulphate) colitis: Oral administration of this sulphated polysaccharide to mice induces a self limiting colitis • TNBS(Trinitrobenzenesufonic acid) colitis: Colonic inflammation is induced by intrarectaladministration of TNBS dissolved in 50% ethanol • 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 immunomodulatorydrugs • The pathogenesis of IBD involves: • Failure of immune regulation. • Genetic susceptibility. • Environmental triggers (microbial flora). • Disruption of the mucosal barrier. • Canine IBD • Small intestine: Lymphocytic-plasmacyticenteritis (LPE), eosinophilic enteritis and eosinophilic gastro-enteritis (EGE) • Large intestine; Lymphocytic-plasmacyticcolitis, eosinophilic colitis, histiocytic ulcerative colitis (HUC) (mainly PAS-positive macrophages), and regional granulomatous colitis (mainly PAS-negative macrophages)
TL1A & DR3 expression in human IBD Healthy Person CD UC TL1A DR3 J Immunol 2003;171;4868-4874
TL1A & DR3 : Evidence of Efficacy Control anti TL1A Gut bacteria Gut bacteria TNBS colitis DSS colitis Control DR3 KO GASTROENTEROLOGY 2008;135:552–567 Mucosal Immunology (2011) 4, 172-185;
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
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.
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.
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
Results: TL1A expression Normal CD UC Human Naïve DSS TNBS Mice
Results: TL1A expression Cynomolgus Human Mice Vasculature (+) Germinal center (-) CD Lamina propria DR3
Mast cells in IBD – Dog, Mice Naive IBD H&E T-blue Naive DSS TNBS
B-lymphocytes-Human IBD Normal CD UC Germinal center Lamina propria
B-lymphocytes-Mice IBD Naive DSS TNBS Germinal center Lamina propria
T-lymphocytes-Human IBD Normal CD UC Germinal center Lamina propria
T-lymphocytes-Mice IBD Naive DSS TNBS Germinal center Lamina propria
B & T lymphocytes- Cynomolgus B-cells T-cells Germinal center Lamina propria
Conclusion 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.
Acknowledgement • Dr. Timothy LaBranche (Industry Mentor) • Dr. Elizabeth Howerth (Academic Mentor) • Dr. ZaherRadi (Pfizer) • Dr. Shawn O’ Neil (Pfizer) • JameelSyed (Pfizer) • Zachery Stewart (Pfizer) • University of Georgia • ACVP-STP Coalition • Studies were funded and supported by DRSD, Pfizer
Thankyou! Pfizer Internal Use