D2 inhibits TLR2- initiated 12p40 transcription (-) TLR2 PGN MDP. MyD88 IRAK ECSIT TRAF6 NIK. Smallest unit of PGN muramyl dipeptide IKK.

Transcription

1 D2 inhibits TLR2- initiated 12p40 transcription CARD CARD NOD2 LRR RICK/Rip2 NIK MDP TRAF6 PGN TLR2 MyD88 IRAK ECSIT (-) IKK Smallest unit of PGN muramyl dipeptide IκB NF-κB atanabe et al, 2004 NF-κB IL-12p40

2 LPS NOD2 model CD14 MD2 TLR-4 CARD CARD NOD2 LRR RICK NIK TRAF6 MyD88 IRAK ECSIT /// IKK IκB NF-κB NF-κB Chronic intracellular bacterial infection Lack of cross-talk to adaptive immune system

3 Increased mucosally- associated bacteria in mucosal biopsies of Crohn s disease patients Swidsinski, et.al. Gastroenterology. 122: 44-54, 2002 Normal control Active Crohn s disease (FISH analysis: BL=Basal lamina; G=Goblet cell; N= Nucleus)

4 ormal Mucosal Defenses minal factors stric acid creatic enzymes e acids istalsis film Tight junctions Intestinal trefoil factor Bacteria PGE 2 Defensins KGF TGF-β FGF 20?GM-CSF Antigens Restitution siga Mucus Blood flow IgA Mucus layer

5 ndogenous Flora - Immune Interaction esident intestinal bacteria profoundly influence mucosal an systemic immune responses. Homeostasis vs. chronic intestinal inflammation is determined by the host s genetically determined innate and adaptive immunologic responses to luminal antigens and adjuvants egulated immune response: tolerance mediated by regulato T cells, dendritic cells and epithelial cells (TGF-β, IL-10, PGE 2, PGJ 2, PPARγ, Α20) ysregulated immune response: chronic relapsing intestinal inflammation mediated by macrophages, T H1 and possibly NKT cells (IL-1β, TNF, IL-12, IL-13, IL-23, IFNγ)

6 rmal Host: Induction of tolerance siga M M Luminal antigens M Bacterial antigens, adjuvants TH 0 Induction of Tolerance TGFβ ( -) IFNγ TH 3 TR 1 IL-10 ( -) TH 1 Mφ IL-12

7

8 - Susceptible Host: ction of pathogenic une responses Luminal Antigens, Adjuvants Leaky mucosal barrier IgG paired mucosal defenses, cterial clearance IL-1β TNF IFNγ TNF TH 1 IL-12 IL-23 TH 2 Dysregulated immune response Loss of Tolerance

9

10 Bacterial components activate innate and adaptive immune responses CD 40 IFNγ Antigen presenting cells (APC) process and present bacterial antigens, are activated by bacterial adjuvants MHC IL-12,18, 23 CD-80 CD-86 Ag CD 40 L TCR CD-28 TH 1 MHC Ag IL-10 TGFβ CD-80 CD-86 TCR IL-10 CTLA-4 TR 1, T H3 T reg CD25

11 Lipopeptides Peptidoglycan LPS HSP60 ds RNA TLR2 TLR4/ MD2 TLR3 Flagellin TLR5 TLR9 MAPK NFκB IL-1R ERK1/2 JNK P38 DAP P50 P65 CARD4/NOD1 CARD15/NOD2 MDP Transcription IL-1 TNFR

12 A variety of bacterial adjuvants stimulate IL-12 production to a greater extent in IL-10 -/- than wild type spleen cells WT IL-10-/- IL-12 (pg/ml) medium alone PG-PS 100 ug/ml LPS 25 ug/ml CpG 6 ug/ml CBL 50 ug/ml

13 IL-10 controls IL-12p40 protein secretion by bone marrow- derived dendritic cells (BMDC) WT WT IL10-/- IL-10-/ IL-10 (pg/ml) unstimulated LPS LPS+IL10 unstimulated LPS 24h LPS 72h (Hoentjen et al, Blood 2005

14 LPS Wild-type IL-10 TLR-4 IL-10R STAT3 P IκB P50 P65 NFκB P50 P65 NFκB + - P P STAT3 oentjen et al, Blood 2005) IL-12p40 mrna

15 LPS TLR-4 IL-10 -/- IL-10 IL-10R STAT3 IκB P50 P65 NFκB P50 P65 NFκB ++++ IL-12p40 mrna

16 Induction of pathogenic vs. regulatory T cells depends on APC interaction CD 40 IFNγ Antigen presenting cells (APC) process and present bacterial antigens, are activated by bacterial adjuvants MHC CD-80 CD-86 Ag CD 40 L IL-12 TCR CD-28 MHC Ag IL-10 TGFβ CD-80 CD-86 TCR IL-10 CTLA-4 TR TH 1 1 TH 3, T reg CD25

17 Genetic Susceptibility Familial incidence 10-15% Conserved familial patterns of disease Twins: monozygotic > dizygotic concordance monozygotic twins Dizyogotic twins: CD 44-58%, UC 6-18% 3-5% > Candidate gene approach - HLA region, TNF Genome-wide search: chromosomes 12, 16 (NOD2 gene), 5 (OCTN-1/2), 1, 6 lvarson J et al. Gastroenterology 124:2003

18 Intestinal epithelial cells are a functional element of the innate immune response and respond to pathogenic and commensal bacteria Pathogenic bacteria Viruses, Cytokines Non-pathogenic enteric bacteria and bacterial componen (D. Haller et al, JBC 2002) TNF, GM-CSF, IL-1 IL-8, GRO, ENA-78, IP-10, MCP-1, RANTES PGE2, NO IL-1, TNF, IL-4, IL-2, IFN-γ IL-12, IL-10

19 Inhibition of B. vulgatus induced NF-κB transcriptional activity in CaCO-2 cells by dominant negative TLR4 Reporter gene assay (κb) 3 -LUC

20 B. vulgatus activates the NF-κB signal transduction pathway in IEC from monoassociated wild-type rats

21 Intestinal epithelial cell- mononuclear cell transwell co-cultures to study immune-mediated cross-talk APC Lymphocytes and monocytes

22 Luciferase Luciferase activity activity (fold (fold induction) induction) B. vulgatus-induced NF-κB transcriptional activity is blocked in lymphocytic but not in monocytic- IEC co-culture culture 12 * * Monocytes Lymphocytes PBMC medium

23 IL 6 secretion (pg/ml) TGFβ1 1 inhibits LPS and B.vulgatus- induced IL-6 6 secretion in CMT-93 cells 180 IL-6 secretion (pg/ml) TGFβ 0 B. vulgatus - LPS

24 TGFβ blocks B.vulgatus-induced IL-6 6 gene expression by ibiting RelA recruitment to the gene promoter (Haller JBC 20 R4 MD-2 TGFβ IKK IκBα NF-κB R-smads (Smad2/3) P P S32/36 p300 P P Co-smads (Smad 4) S536 X His3 acetyl/phosp transcription Nucleus IL-6 6 gene promoter

25 ifferential NF-κB RelA phosphorylation in native IEC from E. aecalis-monoassociated WT and IL-10-/- mice WT 129 SvEv IL-10 -/- 129 SvEv P-RelA P-p44/p42 β-actin Germ-free E. faecalis Germ-free E. faecalis time (days)

26 WT 129 SvEv E. faecalis TLR2 Phospho-RelA Phospho- Erk1/2 faecalis triggers: arly and transient induction of F-κB signaling in native IEC well as cell lines through the LR2 cascade P-RelA Smad4 arly and transient TGF- Smad signaling in native as ell as IEC lines F-β inhibits: STAT3 Histone Phospho-Histone Phospho- Smad2/3 LR2 expression in native as ell IEC lines F-κB signaling and NF-κB pendent gene expression ller, D. et al., J. Immunology 2005 IL-10 IL-6, IP-10, TLR2 TGF-β TGF-R