BARRIER DISRUPTION IN STAT6VT TRANSGENIC MICE AS A POTENTIAL MODEL FOR ATOPIC DERMATITIS SKIN INFLAMMATION Sonia Cristina DaSilva Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Master of Science in the Department of Biochemistry and Molecular Biology, Indiana University November 2010 Accepted by the Faculty of Indiana University, in partial fulfillment of the requirements for the degree of Master of Science Dan F Spandau, Ph.D., Chair Jeffrey B Travers, M.D., Ph.D Master’s Thesis Committee Raymond Konger, M.D Sonal Sanghani, Ph.D ii This is dedicated to my parents, and my best friends Jorge & Tim… “There are only two mistakes one can make along the road to truth; not going all the way, and not starting” – Siddhartha Gautama, Buddha iii Acknowledgments “We don't accomplish anything in this world alone ” -Sandra Day O’Connor, U.S Supreme Court I would like to thank Dr Jeffrey Travers for his constant mentorship, understanding, and confidence in me Thank you for the opportunity to shadow you in your AD clinic I would also like to thank Dr Dan Spandau and Dr Raymond Konger for the constant encouragement and their utter patience I owe my gratitude to Dr Sonal Sanghani for educating me in all the biotechnological techniques that I used in pursuit of my degree I am very fortunate to have wonderful mentors guiding me and willing to let me interrupt their work with my questions I would also like to thank Dr Mark Kaplan for generously providing me with the STAT6VT transgenic mice, and Dr Michael Southall for hosting me at Johnson & Johnson, NJ I thank all the members of the labs where I completed each segment of my project and were instrumental to the technical aspects of this project For Dr Ravi Sahu, Dr Mohammed Al-Hassani, Dr Sarita Sehra, Dr Simarna Kaur, Qiaofang Yi, Davina A Lewis, Badri M Rashid, Evelyn T Nguyen, and Pamela Durant And finally, to Tim, I owe my sincerest gratitude for encouraging me every time that I thought I had lost it You gave me comfort and hope whenever I needed it iv Table of Contents List of Tables……………………………………………….……………… ………… vi List of Figures……………………………………………….……………… ………… vii Abbreviations……………………………………………….……………… ………… viii Introduction….……………….………………………………………… ………… Materials and Methods….…….…………………………………….…………… 11 Results………………….…….……………………………………………… …… 18 Discussion…………….…………………………………………………….………… 23 Figures… ………….………………………………………………….…………… 28 References… ………….……………………………………………………….……… 35 Curriculum Vitae v List of Tables Table Inflammatory cytokine protein expression in STAT6VT transgenic mice treated with repeated SLS vi List of Figures Fig TEWL is augmented in STAT6VT transgenic mice with repeated SLS irritation Fig Barrier disruption in WT versus STAT6VT transgenic mice following repeated SLS treatment Fig STAT6VT mice exhibit enhanced inflammation in the shaved dorsal epidermis following repetitive SLS application Fig STAT6VT transgenic mice feature augmented hyperplasia and active proliferation following repeated SLS treatment Fig Effect of SLS on EDC genes in WT versus STAT6VT transgenic mice Fig Effect of SLS on inflammatory cytokine gene expression in WT versus STAT6VT transgenic mice vii Abbreviations AD BCA cDNA CE EDC FLG GM-CSF IFNγ ICD IL-1ß IL-4 IL-12 IL-13 IVL JAK KLK7 KRT14 KO LOR PBS PCR qRT-PCR SPINK5 SH2 STAT6 STAT6VT SC TBS TEWL TH1 TH2 TNFα WT atopic dermatitis bicinchoninic acid complementary deoxyribonucleic acid cornified envelope epidermal differentiation complex filaggrin granulocyte-macrophage colony-stimulating factor interferon gamma irritant contact dermatitis interleukin-1 beta interleukin-4 interleukin-12 interleukin-13 involucrin Janus kinase kallikrein keratin 14 knockout loricrin phosphate buffered saline polymerase chain reaction quantitative real-time polymerase chain reaction serine peptidase inhibitor Kazal type Src homology domain signal transducer and activator of transcription STAT6 V547A/T548A mutation stratum corneum tris buffered saline transepidermal water loss T-helper Type cells T-helper Type cells tumor necrosis factor alpha wild-type viii Introduction Atopic dermatitis (AD) is a pruritic, chronic inflammatory skin disease with a lifetime prevalence of 10-20% in children and 1-3% in adults, worldwide It is the most common cause of occupational skin disease in adults In the past three decades, prevalence of the disease has increased by two to three-fold in industrialized countries, with higher incidences in urban regions compared to rural regions (Leung & Bieber, 2003) A recent review has described how AD impacts both the child and immediate family (Sehra, et al., 2008) The pruritic feature of AD can cause mental exhaustion, mood changes, lack of concentration in school or work, and an increase in parental and child morbidity The clinical features of AD include mild cases of erythema in localized areas of the body to acute lesions that appear as erythematous macules Lesions tend to occur on the cheeks, scalp and extensor areas of the arms and legs in infants, and in the flexural regions of the extremities in older children (Sehra, et al., 2008) The pathogenesis of AD includes complex interactions between susceptibility genes, environment, and immunological factors (Leung, 2000) Although recent studies have resulted in an enhanced understanding of the pathogenesis of AD, there is still a need for an improved elucidative animal model The systemic immune response of AD involves an increase in blood serum IgE antibodies to nonpathogenic allergens and a decrease in interferon γ levels (IFNγ) Approximately 80% of children with AD will develop either allergic rhinitis or asthma (Leung & Bieber, 2003) Biopsy samples from unaffected skin of patients with AD, compared to healthy, normal skin, show an increase in the number of TH2 cells that regulate interleukin-4 and interleukin-13 (IL-4, IL-13, respectively) (Hamid, et al., 1996) Histologically, there are differences between acute and chronic atopic dermatitis Acute AD lesions demonstrate focal parakeratosis, spongiosis of the epidermis, and inflammatory cell filtrates in the dermis made up of T-cells expressing IL-4 and IL-13, inflammatory dendritic epidermal cells, macrophages, eosinophils, mast cells, and antigen-presenting cells like Langerhans cells On the other hand, chronic AD shows a less pronounced dermal infiltrate and a significant reduction in IL-4 and IL-13 expression Interleukin-5 (IL-5), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-12 (IL-12), and IFNγ are also increased in comparison to the acute phase of AD and there is acanthosis (Dubrac, Schmuth, & Ebner) The increase in IL-5 is generally seen during the transition from acute to chronic AD and may be responsible for prolonged eosinophil survival and function (Hamid, Boguniewicz, & Leung, 1994) Those with a history of AD are more prone to developing irritant contact dermatitis (ICD) of the hands The clinical result of ICD is inflammation caused by the release of proinflammatory cytokines from keratinocytes in response to chemical stimuli (Hogan, 1990) Naive T-cells will differentiate into having either a Type or Type helper T cell phenotype, (TH1 or TH2 respectively), depending on the source of antigenpresenting cells Generally, the TH1 pathway is stimulated in response to intravesicular pathogens in response to infected macrophages On the other hand, TH2 cells are generated when basophils present antigen to the T cell receptor triggering antibody production in B-cells (Kaiko, Horvat, Beagley, & Hansbro, 2008) The skin is responsible for preventing loss of water from the body as well deterring the entry of environmental particulates The function of the epidermal 28 Fig TEWL is augmented in STAT6VT transgenic mice with repeated SLS irritation STAT6VT transgenic and WT C57BL/6 sibling controls were treated for six-day periods with 5% SLS followed by a single six-day period of 10% SLS TEWL(g/hm2) measurements were taken prior to the application of the topical irritant The dates of topical irritation were: Days 1-6, 20-25, 39-44 and 48-53, as indicated STAT6VT mice show a marked increase in TEWL (g/hm2) during each of the application periods as compared to WT mice Results are the mean ± SEM from samples of 5-8 mice Results significantly different from WT, * p