The development and the function of the anterior segment of the eye are important factors in many diseases that affect the eye. Among the most common of these diseases is glaucoma, an optic nerve neuropathy that is often associated with intraocular pressure. In the United States, glaucoma is the second leading cause of blindness, first among African Americans. Hence, an understanding of mechanisms that lead to glaucoma are essential to allow early detection and effective treatment of this progressive and debilitating disease. Recently, we have determined that mutations in the LIM-homeodomain transcription factor LMX1B cause a congenital disease caused nail patella syndrome. This disease affects the development of the limbs and results in renal failure and early onset open angle glaucoma. This insight has allowed us to begin to investigate the underlying molecular and genetic mechanisms leading to congenital glaucoma. By studying the mouse ortholog of human LMX1B, we have determined that lmx1b is expressed in and required for development of tissues that regulate intraocular pressure, linking lmx1b to ocular development and disease. One function of lmx1b in the eye may be to regulate the production of the extracellular matrix. We have also found that lmx1b is not only expressed during eye development, but is also highly expressed in the adult cornea, trabecular meshwork, and iris, suggesting that lmx1b may have important functions in these tissues. To test the hypotheses that lmx1b is expressed in a subset of the cranial mesenchyme, the neural crest, and required in that tissue, we will employ methods of conditional gene targeting in mice. We will extend these studies to test the hypothesis that lmx1b is required for trabecular meshwork formation in adult mice and that lmx1b functions in the adult to regulate important aspects of corneal and trabecular meshwork function. Using these conditionally engineered lmx1b mutant mice, we will explore morphological and molecular changes that accompany selective inactivation of lmx1b in tissues of the eye. These studies will enrich our understanding of molecular mechanisms that contribute to ocular diseases in human, especially glaucoma. Furthermore, these studies will suggest novel diagnostic and therapeutic approaches for the detection and treatment of glaucoma-induced blindness.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY012311-06
Application #
6631437
Study Section
Visual Sciences A Study Section (VISA)
Program Officer
Liberman, Ellen S
Project Start
1998-07-01
Project End
2006-07-31
Budget Start
2003-08-01
Budget End
2004-07-31
Support Year
6
Fiscal Year
2003
Total Cost
$377,500
Indirect Cost
Name
University of Texas MD Anderson Cancer Center
Department
Biochemistry
Type
Other Domestic Higher Education
DUNS #
800772139
City
Houston
State
TX
Country
United States
Zip Code
77030
Liu, Pu; Johnson, Randy L (2010) Lmx1b is required for murine trabecular meshwork formation and for maintenance of corneal transparency. Dev Dyn 239:2161-71
Gould, Douglas B; Reedy, Mark; Wilson, Lawriston A et al. (2006) Mutant myocilin nonsecretion in vivo is not sufficient to cause glaucoma. Mol Cell Biol 26:8427-36
Chen, You-Tzung; Kobayashi, Akio; Kwan, Kin Ming et al. (2006) Gene expression profiles in developing nephrons using Lim1 metanephric mesenchyme-specific conditional mutant mice. BMC Nephrol 7:1
Dunston, Jennifer A; Reimschisel, Tyler; Ding, Yu-Qiang et al. (2005) A neurological phenotype in nail patella syndrome (NPS) patients illuminated by studies of murine Lmx1b expression. Eur J Hum Genet 13:330-5
Kos, R; Reedy, M V; Johnson, R L et al. (2001) The winged-helix transcription factor FoxD3 is important for establishing the neural crest lineage and repressing melanogenesis in avian embryos. Development 128:1467-79