Biology subjects

Achberger, K.

Publications and source records attributed to Achberger, K..

6 recordsLinked to original sources

bioRxiv2026

A mutation-agnostic and allele-specific ASO strategy demonstrates potent functional rescue and retinal preservation in RHO-linked retinitis pigmentosa

Autosomal dominant retinitis pigmentosa (adRP) caused by RHO mutations is a leading form of inherited retinal degeneration. Extensive allelic heterogeneity of RHO pathogenic variants limits the translational applicability of mutation-specific gene therapies. To address this, we developed SNARE (SNP-guided Silencing of Aberrant RHO Expression), a mutation-independent, allele-specific antisense oligonucleotide (ASO) strategy. SNARE selectively suppresses mutant RHO transcripts by targeting the common, benign c.-26A/G single-nucleotide polymorphism (SNP) as an allelic discriminator. Candidate gapmer ASOs were screened in engineered reporter lines and validated in patient-derived retinal organoids, identifying RHOligo-A as the lead c.-26A-targeting candidate. In vitro, RHOligo-A achieved robust, preferential knockdown of the target allele, improving RHO localization in retinal organoids, and demonstrated a favorable safety profile with minimal transcriptomic off-target effects and no detectable immunostimulatory activity. Subsequent validation in a novel, humanized RHOP347L/WT mouse model, achieved sustained c.-26A-linked allele-selective suppression, retinal structure preservation, and significantly restored visual function, upon a single intravitreal administration. These findings establish RHOligo-A and SNARE as a scalable, mutation-independent therapeutic platform with strong translational potential and substantial clinical reach for RHO-associated adRP.

genetics↗

bioRxiv2026

ViTAMIn-O: Democratizing computer vision-based machine learning for stem cell research

Deep Learning (DL) holds exciting potential in automating the prediction of organoid differentiation results. Nevertheless, current models lack adaptability, openness, and robustness in performance. Additionally, broad employments of predictive models in wet-lab settings necessitate machine learning expertise, often not readily available in biologically oriented laboratories. To offer an intuitive solution, we present ColabViTAMIn-O, a code-free platform together with ViTAMIn-O. ViTAMIn-O is a fully open organoid-specific DL model trained and tested on a total of 34 organoid categories, incorporating annotated images across transmitted light microscopy (TLM) modalities at single-organoid resolution. It is adaptable to downstream prediction tasks of varying dataset sizes and outperforms established models even with linear-probing. It performs reliably within a few-shot framework and is even extensible to human embryo TLM imaging data at single specimen level. By releasing our platform, centralized model hub, and datasets, we hope to encourage broader deployments of specialized DL models in stem-cell laboratories.

bioinformatics↗

bioRxiv2021

Aged human iPSC-RPE organoid cultures display hallmarks of drusen formation

Age-related macular degeneration (AMD) is among the most common causes of irreversible vision loss. Disease progression is strongly associated with age-related pathological changes of retinal pigment epithelial (RPE) cells, such as accumulation of intracellular lipid-containing cell debris, extracellular lipid-rich deposits (drusen) and collagen-rich basal laminar deposits. Current AMD models provide a limited understanding of the complex pathomechanisms, revealing the lack of adequate physiological human AMD models. In this study, we developed an in vitro model applicable for the exploration of AMD pathomechanisms and risk factors for AMD progression and drusen formation. Advanced 3D culturing technologies allow long-term cultivation of hiPSC-derived RPE organoids (RPEorg) for up to 360 days, which is the time frame necessary for the development of an AMD-like phenotype. Aged RPEorg exhibit hallmarks of AMD and age-related alterations such as increased autofluorescence, accumulation of lipid droplets, calcification, and the formation of extracellular clusters of the drusen-associated proteins such as apolipoprotein E (APOE) and tissue inhibitor of metalloproteinases 3 (TIMP3). Electron microscopy further reveals drusen-like extracellular deposits mimicking the signs of late drusen formation and AMD progression. In summary, our results demonstrate that hiPSC-derived 3D RPEorg provide a promising model to study age-associated RPE pathology and drusen formation. We show here that RPEorg are applicable for disease modelling studies and early stages of drug development and provide the opportunity to uncover inter-individual genetic and epigenetic factors that alter the course of the disease.

cell biology↗

bioRxiv2021

Human immunocompetent Choroid-on-Chip: a novel tool for studying ocular effects of biological drugs

Disorders of the eye leading to visual impairment are a major issue that affects millions of people. On the other side ocular toxicities were described for e.g. molecularly targeted therapies in oncology and may hamper their development. Current ocular model systems feature a number of limitations affecting human-relevance and availability. To find new options for pharmacological treatment and assess mechanisms of toxicity, hence, novel complex model systems that are human-relevant and readily available are urgently required. Here, we report the development of a human immunocompetent Choroid-on-Chip (CoC), a human cell-based in vitro model of the choroid layer of the eye integrating melanocytes and microvascular endothelial cells, covered by a layer of retinal pigmented epithelial cells. Immunocompetence is achieved by perfusion of peripheral immune cells. We demonstrate controlled immune cell recruitment into the stromal compartments through a vascular monolayer and in vivo-like cytokine release profiles. To investigate applicability for both efficacy testing of immunosuppressive compounds as well as safety profiling of immunoactivating antibodies, we exposed the CoCs to cyclosporine and tested CD3 bispecific antibodies. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=96 SRC="FIGDIR/small/443846v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@506402org.highwire.dtl.DTLVardef@1d5cdd3org.highwire.dtl.DTLVardef@1bc09d3org.highwire.dtl.DTLVardef@2909de_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

bioengineering↗

bioRxiv2021

Human stem cell-based retina-on-chip as new translational model for validation of AAV retinal gene therapy vectors

Gene therapies using adeno-associated viruses (AAVs) are amongst the most promising strategies to treat or even cure hereditary and acquired retinal diseases. However, the development of new efficient AAV vectors is slow and costly, largely because of the lack of suitable non-clinical models. By faithfully recreating structure and function of human tissues, human induced pluripotent stem cell (iPSC)-derived retinal organoids could become an essential part of the test cascade addressing translational aspects. Organ-on-Chip (OoC) technology further provides the capability to recapitulate microphysiological tissue environments as well as a precise control over structural and temporal parameters. By employing our recently developed Retina-on-chip that merges organoid and OoC-technology, we analyzed the efficacy, kinetics and cell tropism of seven first and second generation AAV vectors. The presented data demonstrate the potential of iPSC-based OoC models as the next generation of screening platforms for future gene therapeutic studies.

bioengineering↗

bioRxiv2019

Human Retina-on-a-Chip: Merging Organoid and Organ-on-a-Chip Technology to Generate Complex Multi-Layer Tissue Models

The devastating effects and incurable nature of hereditary and sporadic retinal diseases such as Stargardt disease, age-related macular degeneration or retinitis pigmentosa urgently require the development of new therapeutic strategies. Additionally, the prevalence of retinal toxicities is becoming more and more an issue of novel targeted therapeutic agents. To date, (ophthalmologic) drug development largely relies on animal models. Inadequate translatability of results from animal models to humans, however, limits advances in drug development and discovery. Hence, the establishment of more relevant human tissue-based in vitro models is of upmost importance. The discovery of self-forming retinal organoids (ROs) derived from human embryonic stem cells (hESCs) or human induced pluripotent stem cells (hiPSCs) is a promising approach to model the complex stratified retinal tissue. Yet, ROs lack vascularization and cannot recapitulate the important physiological interactions of matured photoreceptors and the retinal pigment epithelium (RPE). In this study, we present the retina-on-a-chip (RoC), a novel microphysiological model of the human retina integrating more than seven different essential retinal cell types derived from hiPSCs in a vasculature-like perfusion and enabling, for the first time, the recapitulation of the interaction of mature photoreceptor segments with RPE in vitro. We show that this interaction enhances the formation of outer segment like-structures and the establishment of in vivo-like physiological processes such as outer segment phagocytosis and calcium dynamics. In addition, we demonstrate the applicability of the RoC for drug testing, by reproducing the retinopathic side effects of the anti-malaria drug chloroquine and the antibiotic gentamicin. The developed hiPSC-based RoC has the potential to promote drug development and provide new insights into the underlying pathology of retinal diseases.

bioengineering↗