Biology subjects

Wiley, L. A.

Publications and source records attributed to Wiley, L. A..

3 recordsLinked to original sources

bioRxiv2025

Modeling MEK-inhibitor Associated Retinopathy in vitro using human induced-1 pluripotent stem cell-derived retinal pigment epithelial cells

Pharmacologic inhibitors of MEK are important anti-cancer drugs but can result in MEK inhibitor-Associated Retinopathy (MEKAR) in which vision is lost due to serous retinal detachments that form via an unknown mechanism. We hypothesized that the cause of this side effect is drug-induced dysfunction of retinal pigment epithelial (RPE) cells. To test this hypothesis, we used human induced pluripotent stem cell-derived RPE cells. We treated mature, hiPSC-derived RPE cells with selumetinib and measured impacts on RPE-specific function, structure, and gene expression. Selumetinib increases the ability of hiPSC-derived RPE to internalize bovine rod outer segments (1.9 vs 3.0, p=0.0024). It also decreases expression of aquaporin 1 during the first 10 days of treatment (2.7 vs 1.1, p=0.0015). It has no effect on the ability of hiPSC-derived RPE to maintain membrane integrity. Selumetinib alters gene expression of hiPSC-derived RPE, with significant changes in genes involved in transport of ions and small molecules regulating cell volume and lysosomal acidification. Selumetinib may lead to subretinal fluid accumulation by both increasing secretions into this space and decreasing outflow.

molecular biology↗

bioRxiv2025

Sialoglycoconjugate Profiling of Human Choroid, Retinal Pigment Epithelium, and Macular Degeneration Related Lesions

Age-related macular degeneration is a leading cause of central vision loss in the elderly. Early hallmarks of the disease include basal laminar deposit and choriocapillaris degeneration. The location and composition of sialoglycoconjugates in healthy and diseased choroid and disease-related lesions have not been thoroughly examined. This study utilized lectins to examine sialoglycoconjugates in human tissue, specifically Sambucus nigra/Elderberry Bark Lectin (EBL) and Maackia amurensis lectin II (MAL-II), to examine -2,6 and -2,3 sialic acids, respectively. EBL and MAL-II both label the choroid and basal laminar deposit, with slightly different patterns. Whereas MAL-II predominantly labels the choriocapillaris endothelium, EBL also labels Bruchs membrane and extracellular domains surrounding the vasculature (intercapillary pillars). EBL labeling overlaps with the distribution of complement factor H to a greater extent than MAL-II. After treatment with neuraminidase to remove terminal sialic acids, a battery of lectins was applied to sections of choroids. Lectins that recognize {beta}-galactose, N-acetyllactosamine, galactose ({beta}-1,3) N-acetylgalactosamine, and - or {beta}-N-acetylgalactosamine showed increased reactivity, including increased labeling of glycans in basal laminar deposits. This study provides insight into the location and partial identities of sialoglycoconjugates in the human choroid, with possible implications for the pathogenesis of macular degeneration.

cell biology↗

bioRxiv2025

Production of clinical grade patient iPSC-derived 3D retinal organoids containing transplantable photoreceptor cells

Neurodegenerative conditions that affect the retina are currently the leading cause of incurable blindness in the developed world. Although gene and drug therapies are being developed to slow disease progression in some cases, restorative cell replacement approaches are needed for patients with significant vision impairment due to retinal degeneration. While a variety of different cell types have been evaluated in the context of retinal cell replacement, induced pluripotent stem cells (iPSCs), which can be generated and delivered as an autologous therapeutic, are in many ways the most attractive donor cell source currently available. Like embryonic stem cells, iPSCs must be differentiated into the target therapeutic cell type prior to transplantation. For instance, for patients with retinitis pigmentosa who have primary photoreceptor cell disease, photoreceptor cell derivation and enrichment are required prior to transplantation. Although other effective retinal differentiation protocols exist, they are often not fully compatible with clinical manufacturing. In this study, we report development of a xeno-free 3D retinal differentiation protocol based on the most robust adherent/non-adherent 3D differentiation strategies published to date. In addition, we demonstrate that while iPSC reprogramming efficiency is enhanced under reduced oxygen tension (i.e., 5%), efficient embryoid body and subsequent retinal organoid production require standard oxygen levels (i.e., 21%). Finally, we show that photoreceptor precursor cells obtained from 3D retinal organoids derived using the developed protocol under current good manufacturing practices (cGMP) survive in the subretinal space of dystrophic Pde6b-null rats for 1-month post-transplantation and form new synaptic connections with host bipolar neurons.

neuroscience↗