Age-related macular degeneration (AMD) is the most common cause of visual impairment of the elderly in the developed world. Despite the increase in its prevalence within the aging population, its etiology and pathogenesis are poorly understood and treatment options are limited. We and others have demonstrated that HTRA1 may play a major role in genetic susceptibilty to AMD. The objectives of this proposal are to further analyze the possible causative variant(s) in 10q26, define the normal function of HTRA1, and to elucidate the molecular mechanisms leading to macular degeneration. Our central hypothesis is that HTRA1 plays a key role in retinal development, angiogenesis, and extracellular matrix modeling. Guided by this hypothesis, we propose to conduct the following specific aims.
Specific Aim 1 : To identify all SNP variants associated with AMD in LOC387715/HTRA1 region and investigate their role in AMD in transgenic mice. Our preliminary results have defined a major disease haplotype spanning a 10 kb region in 10q26 that explains the major risk of AMD. This region contains previously identified SNP LOC387715/ARMS2 rs10490924 and HTRA1 rs11200638, already shown to be associated with AMD. We propose to identify all SNP variants in this region by comprehensive direct sequencing analysis. Newly discovered SNPs will be used in a case control association study to investigate their association with AMD in a large cohort. Functional studies will be performed in transgenic mice carrying these AMD associated SNPs.
Specific Aim 2 : To determine the role of HTRA1 in retinal development and pathology. HTRA1 is expressed in the retina and RPE. In order to differentiate the role it plays in the RPE independent of that in retina, we will generate conditional knockout mice which delete HTRA1 in either the retina or RPE. Pathology will be examined in the conditional knockout (KO) by ophthalmoscopy, histology, ERG, and HTRA1 expression will be determined by QPCR, western blot and immunohistochemistry (IHC). Loss of HTRA1 function will be determined by measuring the reduction of or inability for choroidal neovascularization (CNV) to take place in homozygous and heterozygous conditional KO mice.
Specific Aim 3 : To examine the role of HTRA1 in AMD pathogenesis in vivo. A. Inhibition of CNV by injection of HTRA1 antibody in a CNV model. Our preliminary data indicate that over-expression of HTRA1 may contribute to AMD pathogenesis in humans. To verify this, we plan to quantify HTRA1 expression and the extent to which an HTRA1 antibody can inhibit CNV in a laser induced CNV model. B. Transgenic mice expressing WT and mutant HTRA1 genes. HTRA1 is a multi functional protein. In order to delineate which function of HTRA1 (protease, TGF? inhibition, or IGF domain) is involved in AMD pathogenesis in vivo, we will generate transgenic mice expressing different HTRA1 mutations. Mutants will lack either protease activity (SA mutant), the PDZ domain (?PDZ), the Mac25 domain (?Mac), or constitutively active protease. We will quantify the development of AMD-like features in these HTRA1 transgenic mice by ophthalmoscopy, angiography, immunohsitochemistry, biochemistry, and histopathology and compare them to age-matched wild-type mice. The identification of genes that have substantial impact on the risk of the disease may define key molecular pathways involved in its pathogenesis. This may lead to therapies directed at the underlying cause and pre-symptomatic diagnostics to allow for earlier intervention and treatment.

Public Health Relevance

This grant application focuses on investigation of a major gene (HTRA1) that causes age-related macular degeneration, the leading cause of blindness with a significant public health impact.

National Institute of Health (NIH)
National Eye Institute (NEI)
Research Project (R01)
Project #
Application #
Study Section
Biology and Diseases of the Posterior Eye Study Section (BDPE)
Program Officer
Chin, Hemin R
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of California San Diego
Schools of Medicine
La Jolla
United States
Zip Code
Bailey, Jessica N Cooke; Gharahkhani, Puya; Kang, Jae H et al. (2018) Testosterone Pathway Genetic Polymorphisms in Relation to Primary Open-Angle Glaucoma: An Analysis in Two Large Datasets. Invest Ophthalmol Vis Sci 59:629-636
Khawaja, Anthony P; Cooke Bailey, Jessica N; Wareham, Nicholas J et al. (2018) Genome-wide analyses identify 68 new loci associated with intraocular pressure and improve risk prediction for primary open-angle glaucoma. Nat Genet 50:778-782
Wang, Wenqiu; Gawlik, Katarzyna; Lopez, Joe et al. (2016) Genetic and environmental factors strongly influence risk, severity and progression of age-related macular degeneration. Signal Transduct Target Ther 1:16016
Pasquale, Louis R (2016) Vascular and autonomic dysregulation in primary open-angle glaucoma. Curr Opin Ophthalmol 27:94-101
Skowronska-Krawczyk, Dorota; Zhao, Ling; Zhu, Jie et al. (2015) P16INK4a Upregulation Mediated by SIX6 Defines Retinal Ganglion Cell Pathogenesis in Glaucoma. Mol Cell 59:931-40
Li, Zheng; Allingham, R Rand; Nakano, Masakazu et al. (2015) A common variant near TGFBR3 is associated with primary open angle glaucoma. Hum Mol Genet 24:3880-92
Luo, Jing; Baranov, Petr; Patel, Sherrina et al. (2014) Human retinal progenitor cell transplantation preserves vision. J Biol Chem 289:6362-71
Zhao, Jack Jiagang; Ouyang, Hong; Luo, Jing et al. (2014) Induction of retinal progenitors and neurons from mammalian Müller glia under defined conditions. J Biol Chem 289:11945-51
Kang, J H; Loomis, S J; Yaspan, B L et al. (2014) Vascular tone pathway polymorphisms in relation to primary open-angle glaucoma. Eye (Lond) 28:662-71
Springelkamp, Henriët; Höhn, René; Mishra, Aniket et al. (2014) Meta-analysis of genome-wide association studies identifies novel loci that influence cupping and the glaucomatous process. Nat Commun 5:4883

Showing the most recent 10 out of 46 publications