Susan Ewart,
Associate Professor
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email: ewart@cvm.msu.edu
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Our research focus is on the molecular mechanisms of inherited diseases. We study animal models of human disease, as well as genetic diseases that primarily affect animal species. Our primary goals are: 1) to understand the genetic predisposition to human asthma and related allergic airway diseases, and 2) to determine the molecular mechanisms of inherited diseases in domestic animals, particularly the horse. To accomplish these goals several diverse research projects are ongoing. One project focuses on the genetic mechanisms that predispose to human asthma, a potentially fatal respiratory disease. We are studying mouse models of human asthma to identify genes that underlie this disease. We recently determined the chromosomal location of three quantitative trait loci (genes), Abhr1, Abhr2 and Abhr3 (for antigen-induced bronchial hyperresponsiveness), that control airway hyperresponsiveness in mice. We are currently investigating the role of several positional candidate genes near the Abhr loci for contributing to airway hyperresponsiveness. In a related project, we are developing molecular tools to use in the study of asthma in cats.
We are also studying anterior segment dysgenesis, a codominantly inherited eye defect that occurs in horses. We recently described the phenotype and inheritance of this disease in the horse and are currently testing candidate genes based on phenotypically homologous eye diseases in humans (congenital aniridia) and mice (small eye). Along with investigating specific equine genetic diseases, we are developing molecular tools in the form of equine genetic markers and sequence polymorphisms to aid the research in other inherited diseases in the horse, such as dwarfism, narcolepsy, and malocclusion in Miniature horses.
Selected publications:
Shubitowski DM, Venta PJ, Douglass CL, Zhou R, and Ewart SL. Polymorphism identification within 50 equine gene-specific sequence tagged sites. Animal Genetics, 2001;32:78-88.
Ewart SL, Kuperman D, Schadt E, Tankersley C, Grupe A, Shubitowski DM, Peltz G, Wills-Karp M. Quantitative trait loci controlling allergen-induced asthma in inbred mice. Am J Respir Cell Mol Biol, 2000; 23:1-9.
Karp CL, Grupe A, Schadt E, Ewart SL, Keane-Moore M, Cuomo PJ, Kohl J, Wahl L, Kuperman D, Germer S, Aud D, Peltz G, Wills-Karp M. Identification of complement 5 (C5) as a susceptibility locus for experimental allergic asthma. Nature Immunology, 2000; 1(3):1-6.
Ewart SL, Ramsey DT, Xu J, and Meyers D. The horse homologue of congenital aniridia conforms to semidominant inheritance. J Heredity, 2000;91(2):93-98.
Ramsey DT, Ewart SL, Render JA, Cook CS, and Latimer CA. Anterior megalophthalmos and megalocornea of Rocky Mountain Horses. Vet Ophthalmol, 1999;2:47-59.
Nicolaides NC, Holroyd KJ, Ewart SL, Eleff SM, Kiser MB, Dragwa CR, Sullivan C, Grasso L, Zhang L-Y, Messler C, Kleeberger SR, Buetow K, and Levitt RC. Interleukin-9: A candidate gene for asthma. Proc Natl Acad Sci USA 1997;94:13175-13180.
Wills-Karp M, Ewart SL. The genetics of allergen-induced airway hyperresponsiveness in mice. Am J Respir Crit Care Med 1997;156:S89-S96.
Ewart SL, Mitzner W, Meyers D, DiSilvestre DA, and Levitt RC. Airway hyperresponsiveness to acetylcholine in mice: segregation analysis and evidence for linkage to chromosome 6. Am J Respir Cell Molec Biol 1996;14:487-495.
Ewart SL, Gavett S, Margolick J, and Wills-Karp M. Cyclosporin A attenuates genetic airway hyperresponsiveness in mice but not through inhibition of CD4+ T cells. Am J Respir Cell Molec Biol 1996;14:627-634.
Other Publications