Roxana A. Radu Laboratory
Retina Biochemistry and Disease Modeling
Understanding and treatment of retinal diseases through research on retinoid metabolism and pigment epithelium biology
Roxana A. Radu, M.D.
Associate Professor
- Vernon O. Underwood Family Chair in Ophthalmology
- Department of Ophthalmology
- Jules Stein Eye Institute
Dr. Radu leads a cutting-edge research program focused on understanding and treating degenerative macular diseases, specifically Stargardt disease (STGD1) and age-dependent macular degeneration (AMD). Dr. Radu’s group has made significant breakthroughs in understanding complex eye diseases. Key discoveries include identifying the ABCA4 gene’s expression in RPE cells, developing innovative "disease-in-a-dish" models using induced pluripotent stem cells, and revealing complement system dysregulation as a common pathological pathway in both STGD1 and AMD. The laboratory is pioneering new approaches by examining retinoid-lipid processing, mitochondrial function, and cellular interactions to identify molecular targets for potential therapeutic interventions.
Key Scientific Questions
- What are the distinct, cell-type-specific roles of ABCA4 in photoreceptors versus RPE, and how does their loss synergize to drive STGD1 pathology?
- How does dysregulated vitamin A-lipid metabolism contribute to retinoid-lipid buildup and metabolic impairment in STGD1 RPE cells?
- How does loss of ABCA4 impair phosphatidylethanolamine-dependent LC3-associated phagocytosis (LAP) and endolysosomal function, leading to toxic bisretinoid and lipid accumulation in RPE?
- Which lipid-sensitive signaling cascades link lipid droplet accumulation to complement and inflammatory activation, and how can these pathways be targeted therapeutically?
- Can human iPSC-derived RPE–retinal organoid co-culture systems recapitulate ABCA4 genotype-specific disease phenotypes and serve as platforms to identify and validate therapeutic targets?
Lab Members
Undergraduate Students
Eudia Sze Rou Ng(she/her)
“Undergraduate”
Eudia studies morphological developments in retinal pigment epithelium cells of mice with a knock out ABCA4 gene (ABCA4 -/-). She is particularly interested in imaging and mapping early morphological changes in the RPE prior to overt cell degradation.
Jaclyn Ohanyan
Undergraduate
Jaclyn studies Retinal Pigmented Epithelial (RPE) cells and organoids in the culture room and their development over time. She is also studying an inflammatory pathway of RPE as a result of varying diets on ABCA4 KO genotype mice.
Simran Purohit(she/her)
Undergraduate
Simran studies how vitamin A-derived lipid accumulation leads to inflammation in STGD1 mouse models using Western blots.
Eesha Vaghasia
Undergraduate
Eesha studies how the expression of the ABCA4 gene can influence various inflammasome pathways in relation to photoreceptors and the RPE. Her current research focuses on the activation of the NLRP3 inflammasome and subsequent age related acceleration of Stargardt Disease.
Marissa Valdez(she/her)
Undergraduate
Marissa studies the accumulation of NLRP3 in the inflammasome pathways to retinal pigment epithelium (RPE) cells in relation to Stargardt's Disease.
Fanny Zheng(She/Her)
Undergraduate
Fanny studies the cellular mechanisms regulating autophagic flux in Stargardt disease. Her current research focuses on assessing LC3 lipidation in Retinal Pigment Epithelium (RPE) cells.
Recent Publications
DGAT1-associated lipid-retinoid dysregulation correlates with metabolic impairment in the RPE of Stargardt disease
Arpita Dave, Eunice Sze Yin Ng, Zhichun Jiang, Jane Hu, Jordan Tatang, Antonio Paniagua, …, Roxana A. Radu, et al.
iScience (2026)
View PublicationDual Knockout Models of the Spatially and Functionally Conserved rgra and rgrb Zebrafish Genes Reveal the Requirement of RGR for the Integrity of Cone‐Mediated Photopic Vision, the Photopic Visual Cycle and Bruch's Membrane Morphology
Grace Ruddin, Tess McCann, Joanna J. Kaylor, Michelle M. Fox, John D. Fehilly, Rebecca Ward, …, Roxana A. Radu, et al.
The FASEB Journal (2026)
View PublicationDysregulated DNA Methylation in Abca4-/- Retinal Pigment Epithelium: Insights into Early Stage of Stargardt Disease
Arpita Dave, Anela Tosevska, Marco Morselli, Emily Tom, Matteo Pellegrini, Dorota Skowronska-Krawczyk, Roxana A. Radu
International Journal of Molecular Sciences (2025)
View PublicationMutant mice with rod-specific VPS35 deletion exhibit retinal α-synuclein pathology-associated degeneration
Cheng Fu, Nan Yang, Jen-Zen Chuang, Nobuyuki Nakajima, Satoshi Iraha, Neeta Roy, …, Roxana A. Radu, et al.
Nature Communications (2024)
View PublicationImpaired cathepsin D in retinal pigment epithelium cells mediates Stargardt disease pathogenesis
Eunice Sze Yin Ng, Jane Hu, Zhichun Jiang, Roxana A. Radu
The FASEB Journal (2024)
View PublicationConditional deletion of miR-204 and miR-211 in murine retinal pigment epithelium results in retinal degeneration
Samuel W. Du, Ravikiran Komirisetty, Dominik Lewandowski, Elliot H. Choi, Damian Panas, Susie Suh, …, Roxana A. Radu, et al.
Journal of Biological Chemistry (2024)
View PublicationMembrane Attack Complex Mediates Retinal Pigment Epithelium Cell Death in Stargardt Macular Degeneration
Eunice Ng, Nermin Kady, Jane Hu, Arpita Dave, Zhichun Jiang, Jacqueline Pei, …, Roxana Radu, et al.
Cells (2022)
View PublicationDawn and dusk peaks of outer segment phagocytosis, and visual cycle function require Rab28
Ailís L. Moran, Stephen P. Carter, Joanna J. Kaylor, Zhichun Jiang, Sanne Broekman, Eugene T. Dillon, …, Roxana A. Radu, et al.
The FASEB Journal (2022)
View PublicationAssessing Variant Causality and Severity Using Retinal Pigment Epithelial Cells Derived from Stargardt Disease Patients
Anna Matynia, Jun Wang, Sangbae Kim, Yumei Li, Anupama Dimashkie, Zhichun Jiang, …, Roxana A. Radu, et al.
Translational Vision Science and Technology (2022)
View PublicationReproducibility of the Rod Photoreceptor Response Depends Critically on the Concentration of the Phosphodiesterase Effector Enzyme
Ala Morshedian, Gabriela Sendek, Sze Yin Ng, Kimberly Boyd, Roxana A. Radu, Mingyao Liu, et al.
Journal of Neuroscience (2022)
View Publication