Using Induced Pluripotent Stem Cell-Derived Retinal Pigmented Epithelium to Study the Effects of Oxidative Stress and Complement Activation in Age-Related Macular Degeneration In Vitro
The retinal pigment epithelium (RPE), a layer of cells under the light-capturing photoreceptors, plays a crucial role in the development of age-related macular degeneration (AMD). In this project we will utilize stem cells engineered from tissue of living humans, known as induced pluripotent stem cells (iPSCs) to study how toxins derived from smoking lead to RPE damage through the activation of the immune complement system. The use of iPSC technology to recapitulate certain aspects of AMD (ie, a “disease-in-a-dish” approach) offers a clear advantage over current models because we can derive tissues from AMD patients, which carry the genetic background of the disease. This will allow us to directly investigate the immune complement system in genetic conditions of AMD, thereby providing a better understanding of disease mechanisms and the ability to test potential therapeutic interventions.
Note: This award was administratively transferred to Co-Principal Investigator, Dr. Bärbel Rohrer, PhD, to act as Principal Investigator for the final few months of the award.
Our long term goal is to identify novel disease mechanisms to design new and effective therapies to treat and/or prevent AMD. In this project we are investigating how toxins derived from cigarette smoke, lead to RPE cell damage through the activation of the immune complement system.
Scientific evidence has demonstrated that cigarette smoke is a major risk factor for AMD and that inflammatory-induced damage plays a central role in the development of the disease. Furthermore, the RPE, a single layer of cells under the light-capturing photoreceptors, is a primary cellular target affected in AMD. Under normal conditions, light and oxygen are essential for good vision; however, they may also damage the RPE and retina, if it weren’t for their natural repair and antioxidant mechanisms. On the other hand, aging and life style factors such as smoking decrease these repair mechanisms, leading to reversible or irreversible tissue damage. However, the mechanisms of RPE damage in AMD are still not fully understood, perhaps due to a lack of good AMD models that address the genetic background of individual patients.
The recent demonstration that adult cells can be genetically sent back to their embryonic stages (stem cells), together with methods to differentiate these cells into specific mature cell types, opened up new avenues to model and understand human diseases (iPSC techniques). Thus, using iPSC-derived RPE cells from AMD patients and controls, we are investigating (1) the basic functional characteristics of iPSC-derived RPE cells from AMD compared with RPE cells from unaffected control patients; and, (2) the effects of smoke-derived oxidative stress, using these same cells, on cellular function and complement activation. In the first point we are characterizing iPSC and iPSC-RPE cells to explore whether there are intrinsic differences in cells derived from diseased and unaffected controls. We test this, for example, by checking for RPE-specific functions. Secondly, we are investigating whether those RPE functions, as well as levels of inflammatory-derived complement molecules, are altered before and after stressing these genetically unique iPSC-RPE cells with cigarette smoke.
The primary innovation in this project is the use of iPSC-RPE derived from AMD patients and controls to address whether there is an underlying genetic susceptibility for AMD. This approach of using genetically distinct patient-derived cells to model AMD in a dish may bridge the gap between clinical observations and the use of human cell lines and murine disease models. The benefits to be gained from these experiments are a better understanding of ways to model complex eye diseases, as well as a better understanding of disease mechanisms. This in turn will improve the accuracy of therapeutic drug screening and the generation of target-specific therapies for AMD.
About the Researcher
Ernesto F. Moreira, MD, is a graduate of the University of Buenos Aires School of Medicine, in Buenos Aires, Argentina, and is currently an Instructor in Department of Ophthalmology at the Medical University of South Carolina, Charleston, SC. He trained as a postdoctoral fellow at the National Eye Institute, National Institutes of Health, with Dr. Ignacio Rodriguez, PhD; and at the Wilmer Eye Institute, Johns Hopkins University School of Medicine, under the mentorship of the late Ruben Adler, MD. Dr. Moreira is interested in understanding the pathogenesis of AMD using stem cell technology in order to design novel and more effective therapies to treat patients. To accomplish this he uses patient-specific iPSC- derived retinal cells to recapitulate certain aspects of the disease in a dish. Using these cells, he is investigating the role of oxidative stress (in particular cigarette smoke) and inflammation in the development of AMD. The importance of this work is that patient-derived cells carry the genetic background of the patients, which is an aspect that is missing from previous AMD models. Prior to receiving the BrightFocus Foundation award, he received as a postdoctoral fellow, the Knights Templar Eye Foundation award to study retinal development.
"This award represents an important step forward in my career as a junior faculty member. It is also important to our research program in the Ophthalmology Department at the Medical University of South Carolina. The foundation laid by this BrightFocus-sponsored research opportunity will allow me to pursue an entry-level competitive grant from the National Institutes of Health (i.e., an RO1 award).
Foundation support, like that from BrightFocus, and the fact that your organization is particularly interested in funding the work of junior faculty members, is essential for the future of scientific research, and particularly so at this time, when government funding seems insufficient. I am extremely thankful to all the donors that make this possible by donating to ophthalmology research programs of the BrightFocus Foundation.
I believe the future is bright for this field; the eye is a particularly accessible organ to study, and new technologies in genetics, such as gene editing and induced pluripotent stem cells technologies, are revolutionizing the field at a fast pace. This is making new and improved therapeutic alternatives a real possibility in the near future."
First published on: July 15, 2015
Last modified on: July 1, 2018