In a recent conversation, Duncan Borthwick (Head of Sales & Marketing) had the opportunity to sit down with Dr. Florian Régent (Head of Ophthalmology) to speak about the the critical role of iPSC-derived cells in studying Dry Age-related Macular Degeneration (AMD) and advancing drug discovery. Below is a summary of the conversation.

Duncan: Hi Florian, thanks for joining us today. We’d love to hear about your work in ophthalmology and some of the exciting updates from your lab. Can you provide a quick refresher for our audience on dry AMD and the role iPSC models play in your research?

Florian: Of course, Duncan. Age-related Macular Degeneration (AMD) is a leading cause of blindness worldwide, affecting over 200 million people, with numbers expected to rise as the global population ages. Dry AMD is the most common form of the disease, affecting 80-90% of AMD patients. Unfortunately, current treatment options are very limited, creating a significant need for new therapies. To develop these therapies, we need good models to assess their efficacy. At Axol, we’ve chosen to use induced pluripotent stem cells (iPSCs) to create robust models. The retinal pigment epithelium (RPE) cells are primarily affected by dry AMD. These cells help nourish the photoreceptors in the eye, and when they dysfunction or die, photoreceptor cells follow, leading to vision loss. So, having a reliable in vitro model with functional RPE cells is crucial to our research.

Duncan: That sounds fascinating. How do you ensure that the RPE cells you generate from iPSCs are functioning properly and mimicking the human tissue in a meaningful way for your experiments?

Florian: That’s a great question. There are two main approaches to obtaining functional RPE cells: primary RPE cells and RPE cell lines. Primary cells resemble in vivo RPE cells at a molecular and functional level but can’t be scaled up for large-scale assays. On the other hand, cell lines are easy to culture, but they don’t function as well as real RPE cells. At Axol, we use iPSC-derived RPE cells because they allow us to scale up production and generate mature, functional cells in large quantities. Our process involves carefully differentiating iPSCs into RPE cells. Each batch is checked for proper morphology (the formation of a monolayer of pigmented cells) and functional markers (like MITF, ZO1, and PMEL17). We also ensure these cells form tight junctions and can perform phagocytosis, both of which are vital functions of RPE cells in vivo.

Duncan: It’s clear there’s a lot of quality control that goes into your work. I also saw some of the advanced equipment at your site during my visit, including the use of the blue light activation system. Can you walk us through the process you use for modeling dry AMD and testing compounds?

Florian: Yes, after we generate high-quality RPE cells, the next step is to model dry AMD by applying relevant stressors to the cells. Dry AMD is a complex disease, and its mechanisms aren’t fully understood. However, one hallmark of aging RPE cells is the accumulation of lipofuscin, which is a byproduct of the visual cycle. Lipofuscin is photosensitive, and when exposed to blue light, it generates reactive oxygen species (ROS), which induce oxidative stress in the cells. In our model, we expose the RPE cells to a compound called A2E, a major component of lipofuscin, and use chronic, repeated dosing with blue light exposure over two weeks to mimic the slow progression of the disease. This process induces oxidative stress and leads to RPE cell degeneration, which mirrors what happens in dry AMD. The entire experiment takes about a month and a half to complete.

Duncan: That’s impressive, Florian. Now, let’s talk about the compounds you test in this model. What endpoints do you measure, and how scalable is your platform for drug discovery?

Florian: In our model, we can measure several key endpoints. For example, we track oxidative stress levels, monitor the secretion of pro-inflammatory cytokines like IL-6 and IL-8, and analyze the expression of genes involved in drug inflammation. We also measure cell viability, which helps us assess the protective effect of potential compounds. If needed, we also integrate human serum into our model to study complement activation. Our platform is compatible with medium- to high-throughput screening. In fact, we’ve already screened a library of 7,000 compounds with great success, demonstrating good reproducibility and minimal variability. We can also scale up for larger screens or perform more in-depth analysis on smaller scales.

Duncan: It sounds like your system is both flexible and highly scalable. You’ve also been working on an exciting project with Amarna Pharmaceuticals. Can you tell us about it?

Florian: Yes, we are happy to be leading the “Halt AMD” project in collaboration with Amarna Pharmaceuticals. This project focuses on assessing the potential of an innovative gene therapy for dry AMD. We’re developing a 3D model that incorporates RPE cells, microglia, and photoreceptor cells, all derived from iPSCs. The role of microglia in dry AMD progression, particularly inflammation, is becoming more recognized, and protecting photoreceptors, the light-sensitive cells responsible for vision, is the ultimate goal. This model will allow us to study how these cell types interact in both a healthy environment and in disease states, which will be extremely valuable for advancing drug discovery, particularly gene therapies for dry AMD.

Duncan: This project sounds like a major leap forward in dry AMD research. Florian, thank you for sharing all these details with us. We’re excited to see how your work progresses and how it can contribute to drug discovery in ophthalmology.

Florian: Thank you, Duncan, and thank you to everyone. At Axol, we’re committed to helping accelerate drug discovery in any way we can. If anyone is interested in learning more about our services or collaborating with us, feel free to reach out.

Florian’s team at Axol Bioscience is at the forefront of dry AMD research, using iPSC-derived RPE cells to model the disease and test new therapies. By combining cutting-edge technology, high-throughput screening, and in-depth analysis, we’re continuing to do our part in supporting the community to building better models of dry AMD to accelerate drug discovery.

Explore how Axol’s iPSC models can be used in your research by contacting us at operations@axolbio.com or discover our latest poster showcasing our latest work: The potential of iPSCs to accelerate drug discovery for AMD.