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Gliadin, Intestinal Permeability, and Celiac Disease: From Innate Immunity to Autoimmunity
1. Gliadin, Intestinal Permeability, and Celiac Disease: From Innate Immunity to Autoimmunity: Alessio Fasano, M.D. Mucosal Biology Research Center University of Maryland School of Medicine
12. The Paracellular Pathway … Tight junctions are a ‘dark horse’ implicated in a host of disease states, ranging from acute injury to chronic inflammation and autoimmune diseases
13. DISCOVERY OF ZONULIN Coomassie Western blot 1 2 3 4 1: Tissue lysate 2: Sephacryl-S300 3: Q-sepharose 4: Immuoaffinity 1 2 3 4 PURIFICATION PROTOCOL FROM HUMAN INTESTINE
22. In Situ IFM of Biopsies from Either Celiac Disease Patients or Healthy Controls Showed Apical Expression of CXCR3 Celiac disease Non-celiac control CXCR3 Actin Nucleus
23. Proposed Zonulin Mechanism of Action Fasano et al, J Clin Invest 1995;96:710-20; el Asmar et al Gastroenterology 2002;123:1607-15 Following Pathway Activation Resting State Freeze-Fracture Zonulin signaling
24. Celiac Disease Pathogenesis: The Continuous Stimulation by Gluten is Necessary to Perpetuate the Autoimmune Process Intestinal Lumen A. Fasano and T. Shea Donohue, Nature Clin Pract Gastroenterol Hepatol 2005;2:416-22 PRR AGA EMA TTG MyD88 dependent Submucosa Bacteria
25. 1) bacterial adhesion, 2) internal signaling, 3) signal transmission to the effector cells, 4) zonulin release on the luminal side 5) zonulin binds to its receptor, 6) cascade of events ending 7) by the TJ opening, leading to 8) water and solutes paracellular passage and 9- “wash out” effect, 10) and paracellular passage of food antigens and macromolecules, 11) GALT stimulation and subsequent undesired effects H 2 O 5 6 8 7 11 10 9 H 2 O Lymphocytes Food Antigens Macromolecules Zonulin Bacteria Zonulin 1 4 2 Zonulin Enterocytes 3 3 El Asmar et al J Gastroenterology 2002;123:1607-1615 Zonulin System – Innate Immunity
39. Blocking the Zonulin-Dependent Increased Intestinal Permeability Aborts The Autoimmune Process Age: 52-54 days Treatment Animal flow Placebo Timeframe T 0 1 2 3 4 5 6 7 14 wks Pre-T 0 AT1001 Placebo 60% T1D (N = 10) (N = 20) (N = 30) AT1001 35% T1D T1D Sapone et al. ADA Meeting 2005: late breakthrough abstract Outcome 0 50 100 150 200 250 300 30 37 44 51 58 65 72 Age (days) Serum glucose (mg/dl) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 LA/MA Ratio ICA + (100%)
40. Diabetes Treatment Study: Treatment of Autoimmune Diabetes with AT-1001 Sapone et al. ADA Meeting 2005: late breakthrough abstract Untreated T1D Treated NO T1D 10X 40X
41. Insulin staining Glucagon staining A B C D Untreated BBDP rats that developed T1D Blocking the Zonulin-Dependent Increased Intestinal Permeability Aborts The Autoimmune Process AT1001-treated BBDP rats that DID NOT develop T1D: No insulitis Islet Immunohistochemistry
42. Insulin staining Glucagon staining A B C D 40X Blocking the Zonulin-Dependent Increased Intestinal Permeability Aborts The Autoimmune Process Islet Immunohistochemistry AT1001-treated BBDP rats that DID NOT develop T1D: Islets recovering from insulitis and islet regeneration 10X
43. Role of Gliadin in Type 1 Diabetes Pathogenesis Zonulin Intestinal Permeability Incidence of T1D BBDP rats on regular diet BBDP rats on GFD BBDP rats on regular diet BBDP rats on GFD BBDR rats on regular diet BBDP rats on regular diet BBDP rats on GFD
45. Sapone et al. Diabetes 2006 Role of Zonulin in T1D in Humans T1D Relatives T1D Controls 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 Serum zonulin (ng/mg protein) n= 339 89 97
46. Serum Zonulin Levels and Intestinal Permeability in T1D, Their Relatives and Controls Intestinal permeability and serum zonulin levels in T1D patients and their relatives. Both parameters were significantly higher in T1D subjects as compared to their relatives. *p=0.04; **p=0.02 Sapone et al. Diabetes 2006
47. Serum Zonulin and in vivo Permeability in Children with Type 1 Diabetes After Gluten Challenge, vs. Relatives Fig. 1. Serum zonulin levels in T1D patients (n=16) and their relatives (N=35) before and after a gluten-containing meal. *<0.05 compared to baseline. Fig. 2. Serum LA/MAin T1D patients (n=16) and their relatives (N=35) 1 hour before and 1 hour after a gluten-containing meal. *<0.0002; **<0.0005 compared to before meal LA/MA. ** 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 0 1 2 3 4 5 Time (hrs) Serum zonulin (ng/mg protein) T1D relatives Gliadin-containing meal * * * 0.000 0.050 0.100 0.150 0.200 0.250 0.300 1 2 3 4 5 Time (hrs) LA/MA ratio T1D relatives *
48. PROPOSED MODEL Proposed role of aberrant intestinal permeability in Type 1 diabetes pathogenesis. Non-self antigens are present in the intestinal lumen (1) and cross the tj barriers in subjects with dysregulation of the zonulin system (2-3). Antigen peptides bind to HLA receptors present on the surface of APC (4). In turn, these peptides are presented to T lymphocytes (5). In genetically susceptible individuals, an aberrant immune response (both umoral and cell-mediated) (6) leads to the autoimmune process mainly targeting the Langherans islets with subsequent insulin deficiency typical of type 1 diabetes (7). 5 Submucosa T B GAD, IA, IA-2 Tk P 2 3 4 6 1 APC Intestinal lumen 6 7 7