The broad objective of this application is to understand the tissue transitions that underlie the embryonic development of the anterior eye, including the role that these transformations play in eye pathologies as well as in normal morphogenesis. The objectives of the present proposal are to decipher the molecular mechanisms that underlie transformation of epithelium to mesenchyme (EMT) and mesenchyme to epithelium (MET) and to explain the physiological mechanism used by the meesenchymal cell to invade and migrate through the matrix. Epithelium is the primitive tissue type, residing on top of extracellular matrix (ECM) as a continuous sheet of adherent cells. Creation of the mesenchymal cell adds complexity to body form, permitting the ECM between epithelia to be inhabited by inwandering cells that diversify ECM composition and migrate great distances, e.g., from neural tube to the cornea of the eye in the case of neural creast. However, inappropriate transformation of epithelium to mesenchyme in the adult can bring about abnormal ECM deposition, as in anterior capsular cataract, and devastating ECM invasion, as in malignant metastasis.
The Specific aims are to study: (1) cellular mechanisms of corneal and uveal mesenchymal cell migration into and through ECM, using the new confocal microscope to view living cells labeled with sophistcated cytoskeletal probes; we believe ours is the first study to address motility mechanisms in malignant choroid melanoma cells and that new insights will be gained about motility in metastasis; (2) molecular mechanisms of the transformation of lens to mesenchyme induced by suspension in collagen gel; this study focuses on the role of signal tranduction initiated by the protoncogene, c-src and the master mesenchymal genes thus activated in the induction of EMT; (3) induction of MET in corneal fibroblasts and choroid meanoma cells; the fibroblasts and malignant melanoma """"""""mesenchyme"""""""" will be transfected with genes for E-cadherin and/or N-Cadherin. MET inducing agents (e.g., Wnt-1 protein) are added in some cases. The results of this study could nominate cadherin-induced MET as a possible way of inhibiting uveal metastasis in vivo.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY009721-08
Application #
2888408
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1992-08-01
Project End
2001-07-31
Budget Start
1999-08-01
Budget End
2000-07-31
Support Year
8
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Harvard University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
082359691
City
Boston
State
MA
Country
United States
Zip Code
02115
Hay, Elizabeth D (2005) The mesenchymal cell, its role in the embryo, and the remarkable signaling mechanisms that create it. Dev Dyn 233:706-20
Kim, Kwonseop; Sirota, Anna; Chen Yh, Yan-hua et al. (2002) Dendrite-like process formation and cytoskeletal remodeling regulated by delta-catenin expression. Exp Cell Res 275:171-84
Kim, Kwonseop; Lu, Zifan; Hay, Elizabeth D (2002) Direct evidence for a role of beta-catenin/LEF-1 signaling pathway in induction of EMT. Cell Biol Int 26:463-76
Kim, K; Hay, E D (2001) New evidence that nuclear import of endogenous beta-catenin is LEF-1 dependent, while LEF-1 independent import of exogenous beta-catenin leads to nuclear abnormalities. Cell Biol Int 25:1149-61
Kim, K; Pang, K M; Evans, M et al. (2000) Overexpression of beta-catenin induces apoptosis independent of its transactivation function with LEF-1 or the involvement of major G1 cell cycle regulators. Mol Biol Cell 11:3509-23
Hay, E D (1999) Biogenesis and organization of extracellular matrix. FASEB J 13 Suppl 2:S281-3
Kim, K; Daniels, K J; Hay, E D (1998) Tissue-specific expression of beta-catenin in normal mesenchyme and uveal melanomas and its effect on invasiveness. Exp Cell Res 245:79-90
Vanderburg, C R; Hay, E D (1996) E-cadherin transforms embryonic corneal fibroblasts to stratified epithelium with desmosomes. Acta Anat (Basel) 157:87-104
Harkin, D G; Hay, E D (1996) Effects of electroporation on the tubulin cytoskeleton and directed migration of corneal fibroblasts cultured within collagen matrices. Cell Motil Cytoskeleton 35:345-57
Hay, E D; Zuk, A (1995) Transformations between epithelium and mesenchyme: normal, pathological, and experimentally induced. Am J Kidney Dis 26:678-90

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