Project description:Corneal organoids are useful tools for disease modeling and tissue transplantation however they have not yet been well studied during maturation. We characterized human iPSC derived corneal organoids at 1, 2, 3 and 4 months of development using single-cell RNA sequencing to determine the cellular heterogeneity at each stage. We found pluripotent cell clusters committed to epithelial cell lineage at 1 month early corneal epithelial, endothelial and stromal cells markers at 2 months, keratocytes as the largest cell population at 3 months, and a large epithelial cell population at 4 months. We compared organoid to fetal corneal development at different stages and found that 4 month organoids closely resemble the corneal cellular complexity of the fetal (16 post conception week) and adult cornea. Using RNA velocity pseudotime trajectory analysis, we found that eye field primordial cells and limbal stem cells appear to give rise to corneal epithelial cells during development.
Project description:The cornea is a protective and refractive barrier in the eye crucial for vision. Understanding the human cornea in health, disease and cell-based treatments can be greatly advanced with cornea organoids developed in culture from induced pluripotent stem cells. While a limited number of studies have investigated the single-cell transcriptomic composition of the human cornea, its organoids have not been examined similarly. Here we elucidated the transcriptomic cell fate map of 4-month-old human cornea organoids and human donor corneas. The organoids harbor cell clusters that resemble cells of the corneal epithelium, stroma and endothelium with sub-populations that capture signatures of early developmental states. Unlike the adult cornea where the largest cell population is stromal, the organoids contain large proportions of epithelial and endothelial-like cells. These corneal organoids offer a three-dimensional model to study corneal diseases and integrated responses of different cell types.
Project description:The human brain has changed dramatically from other primate species, but the genetic and developmental mechanisms behind the differences remains unclear. Here we used single cell RNA sequencing based on 10X technology to explore temporal transcriptomic dynamics and cellular heterogeneity in cerebral organoids derived from human and non-human primates chimpanzee and rhesus macaque stem cells. Using cerebral organoids as a proxy of early brain development, we detect a delayed pace of human brain development relative to the other two primate species. Additional human-specific gene expression patterns resolved to different cell states through progenitors to neurons are also found. Our data provide a transcriptomic cell atlas of primate early brain development, and illustrate features that are unique to humans.
Project description:The human brain has changed dramatically from other primate species, but the genetic and developmental mechanisms behind the differences remains unclear. Here we used single cell RNA sequencing based on 10X technology to explore temporal transcriptomic dynamics and cellular heterogeneity in cerebral organoids derived from human and non-human primates chimpanzee and rhesus macaque stem cells. Using cerebral organoids as a proxy of early brain development, we detect a delayed pace of human brain development relative to the other two primate species. Additional human-specific gene expression patterns resolved to different cell states through progenitors to neurons are also found. Our data provide a transcriptomic cell atlas of primate early brain development, and illustrate features that are unique to humans.
Project description:The 16p11.2 is the most common copy number variant (CNV) associated with Autism Spectrum Disorder (ASD). We used patient-derived cerebral organoids to investigate neurodevelopmental pathways dysregulated by dosage changes of 16p11.2 CNV. To investigate molecular dysregulation in DEL and DUP organoids, we carried out RNA sequencing and Tandem Mass Tag mass spectrometry (TMT-MS) on 1-month and 3-month organoids from the same samples. In proteomic analyses, we quantified a total of 6126 proteins in 1-month and 5481 proteins in 3-month organoids, with 13 and 11 proteins from within 16p11.2 CNV, respectively. Transcriptomic and proteomic profiling of organoids identifies the key drivers of functional effect by 16p11.2 CNV during neocortical development.
Project description:The corneal endothelium plays a primary role in maintaining corneal homeostasis and clarity, and must be surgically replaced with allogenic donor corneal endothelium in the event of visually significant dysfunction. However, a worldwide shortage of donor corneal tissue has led to a search for alternative sources of transplantable tissue. Cultured human corneal endothelial cells (HCEnC) have been shown to restore corneal clarity in experimental models of corneal endothelial dysfunction in animal models, but characterization of cultured HCEnC remains incomplete. To this end, we utilized next-generation RNA sequencing technology to compare the transcriptomic profile of ex vivo human corneal endothelium (evHCEnC) with that of primary HCEnC and HCEnC lines, and to determine the utility of cultured and immortalized corneal endothelial cells as models of in vivo corneal endothelium. Multidimensional analyses of the transcriptome datasets demonstrated that primary HCEnC have a closer relationship to evHCEnC than do immortalized HCEnC. Subsequent analyses showed that the majority of the genes specifically expressed in HCEnC (not expressed in ex vivo corneal epithelium or fibroblasts) demonstrated a marked variability of expression in cultured cells compared with evHCEnC. In addition, genes associated with either corneal endothelial cell function or corneal endothelial dystrophies were investigated. Significant differences in gene expression and protein levels were observed in the cultured cells compared with evHCEnC for each of the genes tested except for AGBL1 and LOXHD1, which were not detected by RNA-seq or qPCR. Our transcriptomic analysis suggests that at a molecular level primary HCEnC most closely resemble evHCEC and thus represent a viable therapeutic option for managing corneal endothelial dysfunction. Our findings also suggest that investigators should perform an assessment of the entire transcriptome of cultured HCEnC prior to determination of the potential clinical utility of the cultured HCEnC for the management of corneal endothelial cell failure. Transcriptomes from ex vivo corneal endothelium, primary cultures and three cell lines were compared. Three samples of each endothelial cell group were submitted for RNA sequencing for a total of 15 samples. The transcriptome for the ex vivo corneal endothelium was used as the reference (i.e., proxy for in vivo corneal endothelium). Transcript abundances for a subset of genes associated with corneal endothelial cell function or disease were validated with qPCR and western blot. Samples of ex vivo endothelium used for validation were independent replicates not used for RNA-sequencing.
Project description:Proper differentiation of corneal epithelial cells (CECs) from limbal stem/progenitor cells (LSCs) is required for maintaining ocular homeostasis and clear vision. Here, using a single-cell transcriptomic atlas, we delineate the comprehensive and refined molecular regulatory dynamics during human CEC development and differentiation. We find that RORA is a CEC-specific molecular switch that initiates and drives LSCs to differentiate into mature CECs by activating PITX1. RORA dictates CEC differentiation by establishing CEC-specific enhancers and chromatin interactions between CEC gene promoters and distal regulatory elements. Conversely, RORA silences LSC-specific promoters and disrupts promoter-anchored chromatin loops to turn off LSC genes. Collectively, our work provides detailed and comprehensive insights into the transcriptional dynamics and RORA-mediated epigenetic remodeling underlying human corneal epithelial differentiation.
Project description:Proper differentiation of corneal epithelial cells (CECs) from limbal stem/progenitor cells (LSCs) is required for maintaining ocular homeostasis and clear vision. Here, using a single-cell transcriptomic atlas, we delineate the comprehensive and refined molecular regulatory dynamics during human CEC development and differentiation. We find that RORA is a CEC-specific molecular switch that initiates and drives LSCs to differentiate into mature CECs by activating PITX1. RORA dictates CEC differentiation by establishing CEC-specific enhancers and chromatin interactions between CEC gene promoters and distal regulatory elements. Conversely, RORA silences LSC-specific promoters and disrupts promoter-anchored chromatin loops to turn off LSC genes. Collectively, our work provides detailed and comprehensive insights into the transcriptional dynamics and RORA-mediated epigenetic remodeling underlying human corneal epithelial differentiation.
Project description:Kidney organoids are a valuable and innovative model to understand genetic diseases, kidney development and transcriptomic dynamics. However, their proteome has not been analyzed so far. Here, we analyzed the organoid proteome trajectory during differentiation. Genes involved in podocytopathies and cystic kidney diseases were abundantly expressed on protein level, distinguishing organoids from almost every available cell culture model. On their pathway to terminal differentiation, organoids developed increased deposition of extracellular matrix. Single cell transcriptomic analysis suggests that most changes locate to podocytes and early podocyte progenitors. This matrix deposition is different from commonly used animal models of glomerular disease. We grew organoids from two independent batches according to the Freedman protocol, and performed proteomic profiling (Freedman, Brooks et al. 2015, Czerniecki, Cruz et al. 2018). The IPSCs were differentiated for a three-week period until first spheroids from. From day 21 of the culture they were used in our experiments up until day 29, where off-target differentiation of organoids becomes an issue.