Interview with Head of Ophthalmology at Axol Bioscience, Dr Florian Regent:
Large-Scale Manufacturing Options for Human IPSC-Derived Retinal Pigment Epithelium (RPE) Cells
Dr Regent completed a PhD in Cell and Molecular Biology at the Université Paris-Saclay, before working at the NIH/NEI (National Eye Institute) for several years. He joined Phenocell as a Team Lead in 2023, remaining Head of Ophthalmology when Phenocell joined the Axol Bioscience family in late 2024. Florian leads the Ophthalmology team, working on delivering iPSC-derived retinal cells and drug discovery services to researchers working in the field of vision loss. We spoke to him about the custom differentiation and large-scale manufacturing services for Retinal Pigment Epithelium (RPE) cells offered by Axol Bioscience.
Q: Why are RPE cells important in ophthalmology?
Retinal Pigment Epithelial Cells (RPE cells) are a monolayer of pigmented cells in direct contact with the photoreceptor cells of the retina, which are responsible for phototransduction. RPE cells play a critical role in supporting photoreceptor function and survival. To fulfil this role, they perform several essential functions, including the regulation of nutrient and waste exchange with the blood, phagocytosis of photoreceptor outer segments, renewal of visual pigments through the visual cycle, and various other tasks necessary for retinal homeostasis.
In dry age-related macular degeneration (AMD), retinal pigment epithelium (RPE) cells play a central role in disease progression. Dysfunction and gradual loss of RPE cells lead to impaired support of photoreceptors, accumulation of toxic byproducts such as lipofuscin, and formation of drusen deposits beneath the retina. These changes disrupt the outer retinal environment and ultimately results in photoreceptor death and progressive central vision loss.
Q: At Axol, we frequently run custom manufacturing projects for clients. Could you tell me about how this works for RPE cells?
Sure, clients can request RPE cells manufactured from Axol cell lines, or we can use our expertise in custom differentiation to manufacture iPSC-derived RPE cells from lines that the client provides themselves.
We can undertake large production runs with timed delivery, or pilot scale production for the early stages of a project.
Q: What is the process for a custom manufacturing project?
The first step is a meeting between the client and Axol’s iPSC experts where we nail down the objectives of the project.
During the next stage, we undertake extensive iPSC characterization. We use flow cytometry to confirm pluripotency-associated marker expression in the iPSC line. When we have ensured we have high-quality starting material, the next step is directed differentiation and optimization. Our directed differentiation process uses cytokines and small molecules to replicate the main steps of retinal development and RPE specification. Built-in optimization provides a safety net for project challenges.
When we’ve produced a pure RPE cell population, we move into the QC stage. This includes rigorous checks for contaminants and optimal post-thaw viability. We undertake ICC and flow cytometry to confirm the expression of lineage-specific markers. We also assess the phagocytic capacity of the produced RPE cells, which is one of their key functions in vivo. If necessary, can perform custom assays to match the project requirements. Our end goal is to ship the desired end-point cells to the client, alongside optimized media and instructions for use.
Q: Do you provide ongoing support for clients?
Of course! We are happy to share our more than 10 years of hard-won experience! Our iPSC experts are happy to continue to give advice if required, for example, for troubleshooting, or how to adapt cells for use in a client’s experimental system.
Q: Which mutations do you think will be of most interest to scientists working in ophthalmology research and drug discovery?
Several single-nucleotide polymorphisms (SNPs) have been implicated in the pathogenesis of age-related macular degeneration (AMD) through genome-wide association studies (GWAS). Variants in CFH, the ARMS2/HTRA1 locus, C3, and APOE are among those showing the strongest correlation with increased AMD risk. Together, these genetic alterations underscore the multifactorial nature of AMD and its association with RPE dysfunction. We have collected cell lines from multiple AMD patients carrying either the protective or “at-risk” alleles of these variants.
Q: What do you think are the most exciting developments in your dry AMD research
In vitro Dry AMD research is moving toward advanced co-culture models that better replicate the complex cellular environment of the human retina. The integration of iPSC-derived RPE cells, microglia, and photoreceptors into 3D in vitro disease models would be a key step forward. These co-culture systems will enable more accurate modeling of the intricate interactions that occur in the retina, providing researchers with tools to study disease mechanisms in a physiologically relevant environment.
The ability to test various therapies in these models with greater accuracy and relevance could pave the way for innovative treatments, helping to address one of the leading causes of vision loss globally.
Read our ebook for more details on Axol Bioscience dry-AMD products and services
Download the poster, “Harnessing the potential of induced pluripotent stem cells to accelerate drug discovery for age-related macular degeneration”
