Biology subjects

Hruba, E.

Publications and source records attributed to Hruba, E..

3 recordsLinked to original sources

bioRxiv2025

Photostimulation Improves Maturation of Human Photoreceptors

The human retina contains photoreceptor cells that detect light and enable vision. The development of these cells involves a tightly regulated cascade of structural and molecular events, and their dysfunction leads to irreversible blindness in many retinal diseases. Human retinal organoids derived from stem cells have become powerful tools to model retinal development and disease, but they often remain immature and lack key features required for full function. Light is not only the sensory target of photoreceptors but also an important developmental signal in vivo. However, light has rarely been used as a deliberate stimulus during in vitro differentiation. Here we show that exposing retinal organoids to rhythmic light flicker at a specific frequency enhances photoreceptor maturation across multiple levels. This stimulation improves the development of outer segments, accelerates the transcriptional transition from precursor to mature photoreceptors, and strengthens functional connectivity with downstream neurons. These findings identify patterned light as a potent and physiologically relevant signal for driving retinal development in vitro. This approach represents a non-invasive and easily scalable method for improving the quality of retinal organoids, with implications for disease modelling, drug discovery and the preparation of photoreceptors for cell-based therapies.

cell biology↗

bioRxiv2025

PRPF8-associated retinitis pigmentosa variant induces human neural retina-autonomous photoreceptor defects

Retinitis pigmentosa (RP) is an inherited retinal disorder characterized by the progressive loss of photoreceptors that currently lacks effective treatment. Here, we investigated the impact of the pathogenic PRPF8-Y2334N variant on neural retina cells in hiPSC-derived retinal organoids. Expression of this variant resulted in photoreceptor defects, including thinning of the outer segment layer. At the molecular level, we observed relatively minor changes in mRNA expression in multiple retinal cells, indicating that neural retina cells are impacted independently of retinal pigment epithelium (RPE). We found splicing alterations in genes associated with neural and retinal diseases, including those involved in intraflagellar transport, suggesting that these genes may represent common targets of splicing factor mutations. We further detected the misexpression of several circular RNAs (circRNAs), which could serve as early biomarkers of splicing defects caused by RP mutations. Together, we present a model of RP that recapitulates photoreceptor degeneration and demonstrates that these defects are independent of RPE erosion.

cell biology↗

bioRxiv2025

Unveiling the Cellular and Molecular Mechanisms of Diabetic Retinopathy with Human Retinal Organoids

Diabetic retinopathy (DR) is a leading cause of vision impairment worldwide, driven by chronic hyperglycaemia and its complex metabolic consequences. While animal models have been widely used to study DR, they often fail to replicate the physiology of human retina. To address this limitation, we employed human retinal organoids as a model to study the effects of hyperglycaemia across various stages of retinal differentiation. Early-stage organoids demonstrated resilience to high glucose levels, maintaining normal morphology, viability, and gene expression. However, advanced-stage organoids displayed significant disruptions, including the downregulation of outer segment-specific genes, which impaired photoreceptor maturation, and a noticeable shortening of photoreceptor outer segments. Transcriptomic analysis revealed substantial changes in pathways related vision including G protein-coupled receptor signalling pathway, response to light stimulus, and visual perception. While photoreceptors were particularly vulnerable, other retinal cell types, including bipolar cells, ganglion cells, and Muller glia, showed greater resilience. Additionally, glial activation, evidenced by increased expression of astrocyte markers, suggested an adaptive response to hyperglycaemia. To validate our findings, we compared our dataset with publicly available transcriptomic datasets from human retinas with DR, confirming key overlaps in pathways related to photoreceptor dysfunction, gliogenesis, and oxidative stress responses. These results establish human retinal organoids as an effective and relevant model for studying the molecular mechanisms of neurodegeneration associated with DR progression.

cell biology↗