1 / 40

INTERACTION OF AN ASTHMA PROMOTING IL4RA ALLELE WITH OXIDATIVE STRESS PATHWAYS

Loida Viera-Hutchins, M.D. Mentor: Talal Chatila, M.D., MSc. INTERACTION OF AN ASTHMA PROMOTING IL4RA ALLELE WITH OXIDATIVE STRESS PATHWAYS. Overall objective. To study the role gene-environment interactions in promoting the development of asthma. Asthma. 20 million

feo
Download Presentation

INTERACTION OF AN ASTHMA PROMOTING IL4RA ALLELE WITH OXIDATIVE STRESS PATHWAYS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Loida Viera-Hutchins, M.D. Mentor: Talal Chatila, M.D., MSc. INTERACTION OF AN ASTHMA PROMOTING IL4RA ALLELE WITH OXIDATIVE STRESS PATHWAYS

  2. Overall objective • To study the role gene-environment interactions in promoting the development of asthma

  3. Asthma • 20 million • 10 million allergic asthma • Increase in the prevalence 75% from 1980-1994 • Children < 5 asthma rates increased >160% from 1980-1994

  4. Asthma Environmental Factors Genetic polymorphism Inter-individual variability

  5. Air Pollution • Ozone (O 3) • Particles • Sulfur Dioxide (SO ) sulfur • Oxides of Nitrogen (NO x) • Volatile Organic Compounds (VOCs)

  6. The impact of particulate pollutants on asthma • Cardiorespiratory morbidity and mortality • Asthma flares • Increased symptom score • Requirement for more frequent medication • Hospitalization

  7. Particulate pollutants & allergic sensitization • Children who live near motorways have increased incidence asthma • In humans intranasal co-administration of Diesel exhaust particles (DEP) and neo-antigen (KHL) → primary sensitization and anti-KHL specific IgE in 9 of 15 atopic patients J Allergy Clin Immunol 1999;1183-8

  8. Murine Models Particle exposure during antigen sensitization increases: • Airway hyper-reactivity • Airway inflammatory cells • Number of goblet cells • Antigen specific IgE levels • Increase in pro-allergic T helper 2 cytokine profile (Th2) IL-5, IL4, IL-13 • Decrease in T helper 1 cytokine IFN-g

  9. Particles • Coarse 2.5–10 µm • Fine ≤2.5 µm • Ultrafine ≤0.1 µm • Diesel Exhaust Particles (DEP) (composed of fine and ultrafine particles)

  10. Particle Composition * *Organic Carbons: polycyclic aromatic hydrocarbons (PAH) and quinones Free Radic Biol Med. 2008 May 1; 44(9): 1689–1699.

  11. Role of oxidative stress in the health effects of particulate pollutants • Oxidative stress is a state of redox disequilibrium • Decrease in the cellular glutathione (GSH)/glutathione disulfide (GSSG) ratio • Activates a number of the redox-sensitive signaling cascades • Responses that could be protective or injurious in nature

  12. Oxidative stress promotes dendritic cell pro-allergic Th2 skewing • DEP induced oxidative stress inhibits TH1 immunity in response to TLR agonist • TH1 immunity restored with administration of antioxidant, N-acetylcysteine Clin Immunol. 1999 Dec;104(6):1183-8.

  13. Asthma Environmental Factors Genetic polymorphism Inter-individual variability

  14. IL4Rαpolymorphism, Q576R • Severe asthma • Severe RSV bronchiolitis • Rapid decline in lung function in smokers • Heightened allergen sensitization in the context of maternal smoking • 70% allele frequency in African Americans vs. 20% in Caucasians, 50% and 4% homozygosity, respectively

  15. Q576R mutation promotes intense allergen-induced airway inflammation and remodeling • Increased peribronchial and perivascular inflammation • Increased goblet cell • Increased bronchoalveolar lavage (BAL) fluid eosinophils • Sub-epithelial cell fibrosis • Augments IL-4R –dependent signaling J Exp Med. 2009 Sep 28;206(10):2191-204.

  16. Specific Aim • Study the impact of Q576R X Diesel exhaust particles (DEP) interaction on allergen induced airway disease. • Hypothesis • DEP acts as an adjuvant to promote allergic airway sensitization • Q576R synergizes with DEP exposure to promote heightened allergic airway inflammation

  17. In-vivo study design: 6-8 week old • Intranasal • Sensitization • Saline • UFP • OVA • UFP+OVA Q576R WT 3 day 1% OVA aerosol challenge

  18. Study Design Q576R WT Total IgE & OVA-IgE ELISA Bronchoalveolar lavage (BAL): Total cell # & diff IL-4, IL-13,IL-6 IL-17A, INF-γ Lung histochemical analysis, PAS staining

  19. In-vitro studies • DEP acts as an adjuvant to promote allergic airway sensitization

  20. Mechanism of DEP associated allergic sensitization • Oxidative stress • Prelim data: Chatila lab performed gene microarray of DEP exposed human dendritic cells • Increase in genes in the oxidative stress pathway • Increase in Jagged1

  21. Notch Th1 vs. Th2 Nat Rev Immunol. 2009 Feb;9(2):116-24.

  22. Notch pathway and asthma • May program cells toward proallergic Th2 vs Th1 pathways • Jagged 1 or Jagged 2 + Notch 1 or 2 Th 2 • DLL1 or DLL4 + Notch3 Th 1 • Administration of Notch pathway inhibitor, Gamma Secretase Inhibitor (GSI) inhibits asthma features . Am J Respir Crit Care Med. 2009 May 15;179(10):875-82

  23. In-vitro protocol Murine bone- marrow DEP X 24 hr: 2.5ug cm2 - 15ug cm2 Flow-cytometry DC confirmation & protein expression Quantitative PCR gene expression

  24. DC culture led to 60-70% DC purity Dendritic cell Gate Unstained sample CD11c+ 68%

  25. DC culture treatment with DEP results in up to 20X increase in Jagged 1 expression 0 2.5 5 10 15 20 units ug/cm2, n=3 per group

  26. DC culture treatment with DEP results in 40% decrease in Notch 1 expression 0 2.5 5 10 15 20 units ug/cm2, n=3 per group

  27. DC culture treatment with DEP results in a reduction of DLL1 0 2.5 5 10 units ug/cm2, n=3 per group

  28. Jagged 2 Notch 2 No difference in Jagged 2 or Notch 2 gene expression

  29. Notch 3 Notch 4 No difference in Notch 3 or Notch 4 gene expression

  30. DLL4 DLL3 No difference in DLL4 or DLL3 gene expression

  31. Flow results Unstained Control CD11c+ Gate ssc FSC

  32. DEP treatment results in suppression of DLL1 Red: DEP treated Blue: Untreated Purple: Negative Control Gate CD11c+ n=3

  33. DEP treated group decreased Notch 2 Red: DEP treatedBlue: UntreatedPurple: Negative Control Gate CD11c+ n=3

  34. No difference in Notch 3 and DLL4 Notch 3 DLL4

  35. Ongoing experiments DEP txd DO11 T cells + Tx OVA Proliferation, CFSE PCR: IL-2, IL-4, IL-13, IFN-gamma, GATA-3, T-bet

  36. Summary • Preliminary results suggest that a potential mechanism by which DEP promotes allergic sensitization TH2 DC programming via the Notch pathway • Assess for differences in the Q576R mice • Confirm these results in-vivo

  37. References • Vercelli, D. 2008. Discovering susceptibility genes for asthma and allergy. Nat Rev Immunol 8:169-182. • Chatila, T.A. 2004. Interleukin-4 receptor signlaing pathways in asthma pathogenesis. Trends Mol. Med. 10:493-499. • Hershey, G.K.K., et al. 1997. The association of atopy with a gain-of-function mutation in the a subunit of the interleukin 4 receptor. N. Engl. J. Med. 337:1720-1725. • Ober, C., et al. 2000. Variation in the Interleukin 4-Receptor alpha Gene Confers Susceptibility to Asthma and Atopy in Ethnically Diverse Populations. Am J Hum Genet 66:517-526. • Howard, T.D., et al. 2002. Gene-gene interaction in asthma: IL4RA and IL13 in a Dutch population with asthma. Am J Hum Genet 70:230-236. • Sandford, A.J., et al. 2000. Polymorphisms in the IL4, IL4RA, and FCERIB genes and asthma severity. J Allergy Clin Immunol 106:135-140.

  38. References • Rosa-Rosa, L., et al. 1999. The R576 IL-4 receptor alpha allele correlates with asthma severity. J Allergy Clin Immunol 104:1008-1014. • Wenzel, S.E., et al. 2007. IL4R alpha mutations are associated with asthma exacerbations and mast cell/IgE expression. Am J Respir Crit Care Med 175:570-576. • Blaeser, F., et al. 2003. Targeted Inactivation of the IL-4 Receptor {alpha} Chain I4R Motif Promotes Allergic Airway Inflammation. J Exp Med 198:1189-1200. • Saxon, A., et al. 2005. Air pollution and allergy: you are what you breathe. Nat Immunol 6:223-226. • McCreanor, J., et al. 2007. Respiratory effects of exposure to diesel traffic in persons with asthma. N Engl J Med 357:2348-2358. • 1Whitekus, M.J., et al. 2002. Thiol antioxidants inhibit the adjuvant effects of aerosolized diesel exhaust particles in a murine model for ovalbumin sensitization. J Immunol 168:2560-2567.

  39. References • Rangasamy, T., et al. 2005. Disruption of Nrf2 enhances susceptibility to severe airway inflammation and asthma in mice. J Exp Med 202:47-59. • Raffi Tachdjian1, Clinton Mathias3, Shadi Al Khatib1, Paul J. Bryce3, Hong S. Kim1, Frank Blaeser4, Brian D. O'Connor2, Danuta Rzymkiewicz1, Andrew Chen1, Michael J. Holtzman5, Gurjit K. Hershey6, Holger Garn7, Hani Harb7, Harald Renz7, Hans C. Oettgen3, and Talal A. Chatila1 Pathogenicity of a disease-associated human IL-4 receptor allele in experimental asthma. J Exp Med. 2009 Sep 28;206(10):2191-204. • Li N, Sioutas C, Cho A, Schmitz D, Misra C, Sempf J, Wang M, Oberley T, Froines J, Nel A.Ultrafine particulate pollutants induce oxidative stress and mitochondrial damage. Environ Health Perspect 2003;111:455–460. • Carine Delayre-Ortheza, Julien Beckera, Frédéric de Blaya, b, Nelly Frossarda, Françoise Ponsa. Exposure to Endotoxins during Sensitization Prevents Further Endotoxin-Induced Exacerbation of Airway Inflammation in a Mouse Model of Allergic Asthma. Int Arch Allergy Immunol 2005;138:298-304

  40. References • Proteomics. 2009 Dec 22. • Health Perspectives 2003; 111:1521-18. • Toxicology Letter 2004; 149: 225-243. • Clin Immunol. 1999 Dec;104(6):1183-8. • Am J Respir Crit Care Med. 2009 May 15;179(10):875-82.

More Related