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Ahsanuddin S, Wu AY. Single-cell transcriptomics of the ocular anterior segment: a comprehensive review. Eye (Lond) 2023; 37:3334-3350. [PMID: 37138096 PMCID: PMC10156079 DOI: 10.1038/s41433-023-02539-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 03/07/2023] [Accepted: 04/11/2023] [Indexed: 05/05/2023] Open
Abstract
Elucidating the cellular and genetic composition of ocular tissues is essential for uncovering the pathophysiology of ocular diseases. Since the introduction of single-cell RNA sequencing (scRNA-seq) in 2009, vision researchers have performed extensive single-cell analyses to better understand transcriptome complexity and heterogeneity of ocular structures. This technology has revolutionized our ability to identify rare cell populations and to make cross-species comparisons of gene expression in both steady state and disease conditions. Importantly, single-cell transcriptomic analyses have enabled the identification of cell-type specific gene markers and signalling pathways between ocular cell populations. While most scRNA-seq studies have been conducted on retinal tissues, large-scale transcriptomic atlases pertaining to the ocular anterior segment have also been constructed in the past three years. This timely review provides vision researchers with an overview of scRNA-seq experimental design, technical limitations, and clinical applications in a variety of anterior segment-related ocular pathologies. We review open-access anterior segment-related scRNA-seq datasets and illustrate how scRNA-seq can be an indispensable tool for the development of targeted therapeutics.
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Affiliation(s)
- Sofia Ahsanuddin
- Department of Ophthalmology, Byers Eye Institute, Stanford University School of Medicine, Stanford, CA, USA
- Department of Ophthalmology, New York Eye and Ear Infirmary of Mount Sinai, New York City, NY, USA
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York City, NY, USA
| | - Albert Y Wu
- Department of Ophthalmology, Byers Eye Institute, Stanford University School of Medicine, Stanford, CA, USA.
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Vöcking O, Famulski JK. Single cell transcriptome analyses of the developing zebrafish eye- perspectives and applications. Front Cell Dev Biol 2023; 11:1213382. [PMID: 37457291 PMCID: PMC10346855 DOI: 10.3389/fcell.2023.1213382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 06/20/2023] [Indexed: 07/18/2023] Open
Abstract
Within a relatively short period of time, single cell transcriptome analyses (SCT) have become increasingly ubiquitous with transcriptomic research, uncovering plentiful details that boost our molecular understanding of various biological processes. Stemming from SCT analyses, the ever-growing number of newly assigned genetic markers increases our understanding of general function and development, while providing opportunities for identifying genes associated with disease. SCT analyses have been carried out using tissue from numerous organisms. However, despite the great potential of zebrafish as a model organism, other models are still preferably used. In this mini review, we focus on eye research as an example of the advantages in using zebrafish, particularly its usefulness for single cell transcriptome analyses of developmental processes. As studies have already shown, the unique opportunities offered by zebrafish, including similarities to the human eye, in combination with the possibility to analyze and extract specific cells at distinct developmental time points makes the model a uniquely powerful one. Particularly the practicality of collecting large numbers of embryos and therefore isolation of sufficient numbers of developing cells is a distinct advantage compared to other model organisms. Lastly, the advent of highly efficient genetic knockouts methods offers opportunities to characterize target gene function in a more cost-efficient way. In conclusion, we argue that the use of zebrafish for SCT approaches has great potential to further deepen our molecular understanding of not only eye development, but also many other organ systems.
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Affiliation(s)
| | - Jakub K. Famulski
- Department of Biology, University of Kentucky, Lexington, KY, United States
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Ruiz-Ceja KA, Capasso D, Pinelli M, Del Prete E, Carrella D, di Bernardo D, Banfi S. Definition of the transcriptional units of inherited retinal disease genes by meta-analysis of human retinal transcriptome data. BMC Genomics 2023; 24:206. [PMID: 37072692 PMCID: PMC10111803 DOI: 10.1186/s12864-023-09300-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 04/07/2023] [Indexed: 04/20/2023] Open
Abstract
BACKGROUND Inherited retinal diseases (IRD) are genetically heterogeneous disorders that cause the dysfunction or loss of photoreceptor cells and ultimately lead to blindness. To date, next-generation sequencing procedures fail to detect pathogenic sequence variants in coding regions of known IRD disease genes in about 30-40% of patients. One of the possible explanations for this missing heritability is the presence of yet unidentified transcripts of known IRD genes. Here, we aimed to define the transcript composition of IRD genes in the human retina by a meta-analysis of publicly available RNA-seq datasets using an ad-hoc designed pipeline. RESULTS We analysed 218 IRD genes and identified 5,054 transcripts, 3,367 of which were not previously reported. We assessed their putative expression levels and focused our attention on 435 transcripts predicted to account for at least 5% of the expression of the corresponding gene. We looked at the possible impact of the newly identified transcripts at the protein level and experimentally validated a subset of them. CONCLUSIONS This study provides an unprecedented, detailed overview of the complexity of the human retinal transcriptome that can be instrumental in contributing to the resolution of some cases of missing heritability in IRD patients.
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Affiliation(s)
- Karla Alejandra Ruiz-Ceja
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei, 34, 80078, Pozzuoli, Italy
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Program in Molecular Life Science, University of Campania "Luigi Vanvitelli", Via Vivaldi, 43, 81100, Caserta, Italy
| | - Dalila Capasso
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei, 34, 80078, Pozzuoli, Italy
- Scuola Superiore Meridionale (SSM, School of Advanced Studies), Genomic and Experimental Medicine Program, University of Naples "Federico II", Largo S. Marcellino, 10, 80138, Napoli, Italy
| | - Michele Pinelli
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei, 34, 80078, Pozzuoli, Italy
| | - Eugenio Del Prete
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei, 34, 80078, Pozzuoli, Italy
| | - Diego Carrella
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei, 34, 80078, Pozzuoli, Italy
| | - Diego di Bernardo
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei, 34, 80078, Pozzuoli, Italy
- Chemical Engineering, University of Naples "Federico II", Piazzale Tecchio, 80, 80125, Napoli, Italy
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei, 34, 80078, Pozzuoli, Italy.
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Via de Crecchio, 7, 80138, Napoli, Italy.
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Dillon N, Cocanougher B, Sood C, Yuan X, Kohn AB, Moroz LL, Siegrist SE, Zlatic M, Doe CQ. Single cell RNA-seq analysis reveals temporally-regulated and quiescence-regulated gene expression in Drosophila larval neuroblasts. Neural Dev 2022; 17:7. [PMID: 36002894 PMCID: PMC9404614 DOI: 10.1186/s13064-022-00163-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/19/2022] [Indexed: 12/12/2022] Open
Abstract
The mechanisms that generate neural diversity during development remains largely unknown. Here, we use scRNA-seq methodology to discover new features of the Drosophila larval CNS across several key developmental timepoints. We identify multiple progenitor subtypes - both stem cell-like neuroblasts and intermediate progenitors - that change gene expression across larval development, and report on new candidate markers for each class of progenitors. We identify a pool of quiescent neuroblasts in newly hatched larvae and show that they are transcriptionally primed to respond to the insulin signaling pathway to exit from quiescence, including relevant pathway components in the adjacent glial signaling cell type. We identify candidate "temporal transcription factors" (TTFs) that are expressed at different times in progenitor lineages. Our work identifies many cell type specific genes that are candidates for functional roles, and generates new insight into the differentiation trajectory of larval neurons.
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Affiliation(s)
- Noah Dillon
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, OR, 97403, Eugene, USA
| | - Ben Cocanougher
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Chhavi Sood
- Department of Biology, University of Virginia, VA, 22904, Charlottesville, USA
| | - Xin Yuan
- Department of Biology, University of Virginia, VA, 22904, Charlottesville, USA
| | - Andrea B Kohn
- Whitney Laboratory for Marine Biosciences, University of Florida, FL, 32080, St. Augustine, USA
| | - Leonid L Moroz
- Whitney Laboratory for Marine Biosciences, University of Florida, FL, 32080, St. Augustine, USA
| | - Sarah E Siegrist
- Department of Biology, University of Virginia, VA, 22904, Charlottesville, USA
| | - Marta Zlatic
- MRC Laboratory of Molecular Biology, Dept of Zoology, University of Cambridge, Cambridge, UK.,Janelia Research Campus, VA, Ashburn, USA
| | - Chris Q Doe
- Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, OR, 97403, Eugene, USA.
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Wu Y, Wu Y, Liu K, Liu H, Wang S, Huang J, Ding H. Identification of Genetic Predisposition in Noncirrhotic Portal Hypertension Patients With Multiple Renal Cysts by Integrated Analysis of Whole-Genome and Single-Cell RNA Sequencing. Front Genet 2021; 12:775470. [PMID: 34868264 PMCID: PMC8633307 DOI: 10.3389/fgene.2021.775470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/26/2021] [Indexed: 01/16/2023] Open
Abstract
Background and Aims: The multiple renal cysts (MRC) occur in some patients with noncirrhotic portal hypertension (NCPH) could be a subset of ciliopathy. However, the potential genetic influencers and/or determinants in NCPH with MRC are largely unknown. The aim of this study was to explore the potential candidate variants/genes associated with those patients. Methods: 8,295 cirrhotic patients with portal hypertension were enrolled in cohort 1 and 267 patients affected with NCPH were included in cohort 2. MRC was defined as at least two cysts in both kidneys within a patient detected by ultrasonography or computed tomography. Whole-genome sequencing (WGS) was performed in nine patients (four from cohort 1 and five from cohort 2). Then we integrated WGS and publicly available single-cell RNA sequencing (scRNA-seq) to prioritize potential candidate genes. Genes co-expressed with known pathogenic genes within same cell types were likely associated NCPH with MRC. Results: The prevalence of MRC in NCPH patients (19.5%, 52/267) was significantly higher than cirrhotic patients (6.2%, 513/8,295). Further, the clinical characteristics of NCPH patients with MRC were distinguishable from cirrhotic patients, including late-onset, more prominent portal hypertension however having preserved liver functions. In the nine whole genome sequenced patients, we identified three patients with early onset harboring compound rare putative pathogenic variants in the known disease gene PKHD1. For the remaining patients, by assessing cilia genes profile in kidney and liver scRNA-seq data, we identified CRB3 was the most co-expressed gene with PKHD1 that highly expressed in ureteric bud cell, kidney stromal cell and hepatoblasts. Moreover, we found a homozygous variant, CRB3 p.P114L, that caused conformational changes in the evolutional conserved domain, which may associate with NCPH with MRC. Conclusion: ScRNA-seq enables unravelling cell heterogeneity with cell specific gene expression across multiple tissues. With the boosting public accessible scRNA-seq data, we believe our proposed analytical strategy would effectively help disease risk gene identification.
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Affiliation(s)
- Yanjing Wu
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital, Affiliated with Capital Medical University, Beijing, China
| | - Yongle Wu
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital, Affiliated with Capital Medical University, Beijing, China
| | - Kun Liu
- Department of General Surgery, Beijing Friendship Hospital, Affiliated with Capital Medical University, Beijing, China
| | - Hui Liu
- Department of Pathology, Beijing You'an Hospital, Affiliated with Capital Medical University, Beijing, China
| | - Shanshan Wang
- Beijing Institute of Hepatology, Beijing You'an Hospital, Affiliated with Capital Medical University, Beijing, China
| | - Jian Huang
- Experimental Center, Beijing Friendship Hospital, Affiliated with Capital Medical University, Beijing, China
| | - Huiguo Ding
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital, Affiliated with Capital Medical University, Beijing, China
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