Biology subjects

Liang, H. H.

Publications and source records attributed to Liang, H. H..

4 recordsLinked to original sources

bioRxiv2025

Patient induced pluripotent stem cells identify specificities of a reticular pseudodrusen phenotype in age-related macular degeneration

BackgroundAge-related macular degeneration (AMD) is a leading cause of vision loss. Reticular pseudodrusen (RPD), deposits on the apical side of the retinal pigment epithelium (RPE), signify a distinctive and critical AMD phenotype. Yet, their molecular basis and relationship to the conventional drusen seen in AMD remain unclear. ResultsWe generated induced pluripotent stem cell-derived RPE cells from a clinically phenotyped cohort comprising only individuals with conventional drusen (AMD/RPD-) or drusen coexisting with RPD (AMD/RPD+). From these cells, we generated single-cell transcriptomics, proteomics, and functional data to identify differences between the two cohorts. We show that AMD/RPD+ RPE cells exhibit enrichment in extracellular matrix (ECM) remodelling, cytoskeletal, and hypoxia-responsive programs, whereas AMD/RPD- RPE cells display a relatively greater representation of mitochondrial and protein homeostasis pathways. Both subtypes engaged pathways classically linked to ageing, including ECM remodelling and mitochondrial function, but differed in the direction and extent of these changes. Expression and protein quantitative trait loci (QTLs) highlight shared genetic influences on mitochondrial and iron-handling pathways, while disease-interacting eQTLs and transcriptome-wide association study identify regulatory signals that are distinctive of the RPD subtype within AMD, including through regulation of ECM. Functionally, all iPSC-derived RPE formed drusen-like deposits in vitro: AMD/RPD-lines generated more basal deposits, whereas AMD/RPD+ cells exhibited greater structural instability under bisretinoid-induced stress. ConclusionsThese findings indicate that AMD with and without RPD represent mechanistically distinct entities and provide novel insight into the molecular mechanisms underlying disease heterogeneity in AMD.

genetics↗

bioRxiv2021

Retinal ganglion cell-specific genetic regulation in primary open angle glaucoma

To assess the transcriptomic profile of disease-specific cell populations, fibroblasts from patients with primary open-angle glaucoma (POAG) were reprogrammed into induced pluripotent stem cells (iPSCs) before being differentiated into retinal organoids and compared to those from healthy individuals. We performed single-cell RNA-sequencing of a total of 330,569 cells and identified cluster-specific molecular signatures. Comparing the gene expression profile between cases and controls, we identified novel genetic associations for this blinding disease. Expression quantitative trait mapping identified a total of 2,235 significant loci across all cell types, 58 of which are specific to the retinal ganglion cell subpopulations, which ultimately degenerate in POAG. Transcriptome-wide association analysis identified genes at loci previously associated with POAG, and analysis, conditional on disease status, implicated 54 statistically significant retinal ganglion cell-specific expression quantitative trait loci. This work highlights the power of large-scale iPSC studies to uncover context-specific profiles for a genetically complex disease.

genetics↗

bioRxiv2020

Investigating the role of APOE: limitations of human pluripotent stem cell-derived cerebral organoids

Apolipoprotein E (APOE) is the most important susceptibility gene for late onset of Alzheimers disease, with the presence of APOE-{varepsilon}4 associated with increased risk of developing Alzheimers disease. Here, we reprogrammed human fibroblasts from individuals with different APOE-{varepsilon} genotypes into induced pluripotent stem cells, and generated isogenic lines with different APOE profiles. We then differentiated these into cerebral organoids for six months and assessed the suitability of this in vitro system to measure APOE, {beta} amyloid, and Tau phosphorylation levels. We identified intra- and inter-variabilities in the organoids cell composition. Using the CRISPR-edited APOE isogenic lines, we observed more homogenous cerebral organoids, and similar levels of APOE, {beta} amyloid, and Tau between the isogenic lines, with the exception of one site of Tau phosphorylation which was higher in the APOE-{varepsilon}4/{varepsilon}4 organoids. These data describe that pathological hallmarks of AD are observed in cerebral organoids, and that their variation is mainly independent of the APOE-{varepsilon} status of the cells, but associated with the high variability of cerebral organoid differentiation. It demonstrates that the batch-to-batch and cell-line-to-cell-line variabilities need to be considered when using cerebral organoids.

neuroscience↗

bioRxiv2017

Mitochondrial replacement in an iPSC model of Leber Hereditary Optic Neuropathy.

Cybrid technology was used to replace Leber hereditary optic neuropathy (LHON) causing mitochondrial DNA (mtDNA) mutations from patient-specific fibroblasts with wildtype mtDNA, and mutation-free induced pluripotent stem cells (iPSCs) were generated subsequently. Retinal ganglion cell (RGC) differentiation demonstrates increased cell death in LHON-RGCs and can be rescued in cybrid corrected RGCs.

cell biology↗