Summer 2019
Project Dates:  August 1, 2019 – July 31, 2020

Unraveling the Proteolytic Landscape Regulating LOXL1 Implications in the Development of Pseudoexfoliation Syndrome
Principal Investigator: Fernando Rodriguez Pascual, PhD
Centro de Biologia Molecular “Severo Ochoa” (CSIC/UAM); Madrid, Spain

While precise pathogenesis of PEX syndrome remains unknown, the identification of genetic variants in the LOXL1 gene strongly associated to the disease has opened new avenues for the investigation on its molecular causes. The protein product of the LOXL1 gene belongs to the lysyl oxidase (LOX) family, a group of enzymes contributing to build the extracellular matrix (ECM) by promoting the covalent association (cross-linking) of elastin and collagens. In particular, LOXL1 plays an important role in the formation of elastic fibers, the ECM scaffold mostly imparting elasticity to animal tissues, an observation very consistent with its identification as an integral part of the PEX deposits. With the support of a previous grant from The Glaucoma Foundation, we initiated a line of research aiming to investigate the proteolytic processing of LOXL1 and its potential implications in the development of PEX syndrome. Far from being completed, our results provide a glimpse of the complexity of the proteolytic landscape regulating LOXL1 expression and activity, anticipating exciting findings potentially important for the development of PEX syndrome. Here we apply for a renewal of the support from TGF to accomplish the characterization of LOXL1 proteolytic regulation and to investigate its pathological relevance in the development of PEX syndrome.

Role of LOXL1 Activity in TGFβ-1-Mediated Fibrosis in the Conventional Outflow Pathway
Principal Investigator: Heather Schmitt, BS, MS, PhD
Duke University; Durham, NC 

The proposed research is designed to investigate the regulatory role of the LOXL1 protein that is associated with risk of pseudoexfoliation glaucoma. We are interested in how LOXL1 activity contributes to elevation in eye pressure that is typical of pseudoexfoliation glaucoma. Specifically, we will investigate the relationship between LOXL1, a signaling molecule called TGFβ-1 and eye pressure using a mouse model. TGFβ-1 is often elevated in eyes of people with pseudoexfoliation glaucoma, and it is known to induce “scarring” that causes elevated eye pressure. Results from this project will provide a better understanding of disease mechanism and may lead to targeted clinical interventions for pseudoexfoliation glaucoma.

New Understanding from Mouse Lines with Features of Pseudoexfoliation Syndrome
Principal Investigator: Yong Yuan, PhD
College of Medicine, University of Cincinnati; Cincinnati, Ohio

Pseudoexfoliation syndrome is the most identifiable cause of open-angle glaucoma. Animal models are critical tools for finding the cause of the disease and for testing potential treatment regimens. Currently, no animal model is available that can recapitulate the symptoms of this disease. We found features of Pseudoexfoliation syndrome in several mouse lines with genetic defects affecting cellular functions. The objective of this proposal is to find what is the common cause of the disease among these mouse lines. New knowledge obtained from this study will lead to a better understanding of the disease as well as new strategies for combating the disease.

SPRING 2019
Project Dates:  April 1, 2019 – March 31, 2020

Growth Differentiation Factor 15 Levels in Pseudoexfoliation Glaucoma
Principal Investigator: Rajendra Apte, MD, PhD
Washington University; St. Louis, MO

Loss of vision can make it more difficult for people to work, get around, and enjoy daily life. The number one cause of irreversible vision loss in the world is glaucoma. There are several kinds of glaucoma, all of which can lead to the death of cells in the eye that send visual information to the brain. Preventing these cells from dying is an important part of the treatment for glaucoma. However, it can be difficult for physicians to identify which patients are at highest risk of developing glaucoma, or having their glaucoma get worse over time. Finding a marker, such as a protein in the eye, whose presence might predict whether glaucoma will get worse would make it possible for physicians to better determine whether a patient should have surgery or another treatment. This project will study a protein called growth differentiation factor 15 (GDF-15), which is associated with retinal stress in rodents and humans. By measuring the levels of this protein in human patients with glaucoma before and after surgery, we hope to understand whether there is a relationship between GDF-15 levels in the eye, the severity of glaucoma, and success of glaucoma surgery. If high GDF-15 levels are linked with more severe glaucoma, it could be used as a marker to help determine treatment for patients at the highest risk of developing severe glaucoma.

Metabolomic Analyses of Aqueous Humor of Pseudoexfoliation Glaucoma
Principal Investigator: Sanjoy K. Bhattacharya, M. Tech, PhD
Bascom Palmer Eye Institute, University of Miami Miller School of Medicine; Miami, FL

We will identify the small molecules in the clear fluid of the front part of the eye termed aqueous humor. These small molecules are involved in all day-to-day functions of biological tissues in the eye. This analysis will show a difference in small molecules between pseudoexfoliation glaucoma and normal eyes. Their addition (for example the molecules that provide energy) or removal (for example known toxic molecules) may be early intervention strategies for treating pseudoexfoliation glaucoma.

Winter 2018
Project Dates:  January 14, 2019 – January 13, 2020

Evaluating the Effect of Ocular UV Exposure as a Major Causative Factor in a Risk Model for Exfoliation Syndrome in Indian Population.
Principal Investigator: Rashima Asokan, PhD
Medical Research Foundation, Sankara Nethralaya; Chennai, India

Certain changes in the genetic makeup of an individual make them more susceptible to developing exfoliation syndrome (XFS), the major cause of secondary glaucoma and associated vision loss. Similarly, environmental factors such as lifetime ocular UV exposure through solar radiation, inflammation and low oxygen supply to eye tissues also are known to play a role in XFS disease progression.  However, the extent of influence that the factors have individually or in combination remains uncertain and needs to be investigated. This study uses a single group of patients to address this issue and hopes to generate a profile accounting for the effect of both genetic and non-genetic factors in XFS disease pathology.

Towards an Understanding of the Roles of LOXL1 and BMP-1 in Exfoliation Syndrome
Principal Investigator: Ernst R. Tamm, MD
University of Regensburg; Regensburg, Germany 

Exfoliation syndrome (XFS) is characterized by the deposit of whitish fluffy material throughout the anterior eye segment.  Variants in the gene that codes for the protein LOXL1 are associated with exfoliation syndrome, and genetic and/or environmental factors may cause elevated levels of LOXL1 in the eye.  This project tests the idea that cleavage of LOXL1 (when present in high amounts) by the protein BMP-1 causes molecular changes that induce the formation of exfoliation material. Investigators will increase BMP-1 levels in mouse eyes via gene transfer and examine the eyes for signs of exfoliation material. The genetically engineered mice already have high levels of LOXL1 in the eye. Parallel cell culture experiments will elucidate the molecular mechanisms of the LOXL1/BMP-1 interaction.

FALL 2018
Project Dates:  September 17, 2018 – September 16, 2019

Elastic Fibers and Exfoliation Glaucoma
Principal Investigator: Rachel Kuchtey, MD, PhD
Vanderbilt Eye Institute; Nashville, TN

In order to effectively treat exfoliation glaucoma (XFG), precise understanding of its molecular mechanisms is needed. The breakthrough genetic discoveries within the last decade have paved the pathways leading toward this goal. Lysyl oxidase-like 1 () is the most significant gene associated with XFG and the interaction between LOXL1 and fibrillin-1 has been increasingly recognized as they are two essential elements for proper elastic fiber formation and function. This study will use mouse models to study these two key molecules, affording the unique opportunity to test the hypothesis that mice with dual defects of those two proteins have more severe XFG. If successful, new treatments could be quickly tested.

Identifying Changes in Protein Syntheses and Secretion Induced by PXFG-Associated LOXL1 Mutants
Principal Investigator: Joshua Morgan, PhD
University of California; Riverside, CA

Pseudoexfoliative glaucoma (PXFG) occurs due to the production of extracellular deposits within the eye. By inhibiting the flow of aqueous humor, these deposits lead to a dangerous increase in IOP, the hallmark of glaucoma. In this project, investigators use a sequencing technique, ribosome profiling, to understand how mutations in the gene LOXL1 and PXFG-associated molecules alter the production and secretion of proteins. This knowledge will provide increased understanding as to how changes in protein production within the cell can contribute to the formation of these deposits.

SPRING 2018
Project Dates:  June 1, 2018 – May 31, 2019

Robust Mouse Models of Exfoliation Glaucoma
Principal Investigator: Michael Anderson, PhD
University of Iowa; Iowa City, IA

While some mouse models of exfoliation glaucoma exist, they lack some key features of the human disease. This project proposes generating new mouse models of exfoliation syndrome (XFS) by screening animals with targeted manipulations to genes that are known genetic risk factors for human disease. These mice could be used by the research community in a wide range of studies that will expedite development of new treatments and bring us closer to finding a cure.

Winter 2017
Project Dates:  February 1, 2018 – January 31, 2019

The Role of Autophagy and Mitochondrial Dysfunction in the Pathogenesis of Exfoliation Glaucoma
Principal Investigator: John H. Fingert, MD, PhD
University of Iowa; Iowa City, IA

Exfoliation syndrome and exfoliation glaucoma at their core are caused by defects in cellular processes. Preliminary studies have suggested that abnormalities in the processes that cells use to eliminate waste products (autophagy) and by which cells produce energy in their mitochondria may be culprits in exfoliation syndrome. This study will comprehensively test a panel of cell lines from exfoliation patients and control subjects for abnormalities to determine if these cellular processes are involved in exfoliation glaucoma.

Optimization of a Cell Culture Model for Pseudoexfoliation Syndrome
Principal Investigator: Pedro Gonzalez, PhD
Duke University; Durham, NC

Currently there is limited information about the mechanisms leading to the production of exfoliation material and no specific treatment to prevent its accumulation in the eye. A major limitation is the lack of experimental models in which to identify treatments to inhibit the production of exfoliation material. The potential of using induced pluripotent stem cells from exfoliation donors to generate a cell culture model for the disease is being investigated. Preliminary results show that under certain conditions it is possible to replicate the formation of a material similar to that observed in the tissue of exfoliation patients. The objective is to validate this cell culture model for exfoliation syndrome, which would open new avenues to understand the disease and develop treatments.

Lysyl Oxidase-Like 1 (Loxl1) Dysregulation Promotes Reactive Astrocytosis by Altering Calcium Signaling in Optic Nerve Head Astrocytes
Principal Investigator: Simon Kaja, B.Sc., PhD
Edward Hines Jr. VA Hospital, Hines, IL; Loyola University Chicago, Chicago, IL

Genetic factors can predispose to exfoliation glaucoma, however, the exact molecular mechanisms leading to the full-blown disease are still unknown. This investigation is studying a novel hypothesis of how an individual’s genetic makeup can cause exfoliation glaucoma. Specifically, the project is studying how genetic factors alter communication within and between cells in the eye. Identifying broken chains in cellular communication can help devise novel therapies for treating exfoliation glaucoma.

Development of a Screening System to Identify Treatment Candidates for Exfoliation
Principal Investigator: Konstantin Petrukhin, PhD
Columbia University Medical Center; New York, NY

This study’s objective is to identify and characterize inhibitors of the gene that is associated with XFG, LOXL1 (lysyl oxidase-like 1). The overall goal of the proposed study is to develop an assay for LOXL1 modulators and to screen for compounds that inhibit it with the ultimate goal of developing a potent, selective, and non-toxic treatment for exfoliation glaucoma that can be topically administered as eye drops.