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Shafiee A, Sun J, Ahmed IA, Phua F, Rossi GR, Lin CY, Souza-Fonseca-Guimaraes F, Wolvetang EJ, Brown J, Khosrotehrani K. Development of Physiologically Relevant Skin Organoids from Human Induced Pluripotent Stem Cells. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2304879. [PMID: 38044307 DOI: 10.1002/smll.202304879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/28/2023] [Indexed: 12/05/2023]
Abstract
The development of skin organs for studying developmental pathways, modeling diseases, or regenerative medicine purposes is a major endeavor in the field. Human induced pluripotent stem cells (hiPSCs) are successfully used to derive skin cells, but the field is still far from meeting the goal of creating skin containing appendages, such as hair follicles and sweat glands. Here, the goal is to generate skin organoids (SKOs) from human skin fibroblast or placental CD34+ cell-derived hiPSCs. With all three hiPSC lines, complex SKOs with stratified skin layers and pigmented hair follicles are generated with different efficacies. In addition, the hiPSC-derived SKOs develop sebaceous glands, touch-receptive Merkel cells, and more importantly eccrine sweat glands. Together, physiologically relevant skin organoids are developed by direct induction of embryoid body formation, along with simultaneous inactivation of transforming growth factor beta signaling, activation of fibroblast growth factor signaling, and inhibition of bone morphogenetic protein signaling pathways. The skin organoids created in this study can be used as valuable platforms for further research into human skin development, disease modeling, or reconstructive surgeries.
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Affiliation(s)
- Abbas Shafiee
- Herston Biofabrication Institute, Metro North Hospital and Health Service, Brisbane, QLD, 4029, Australia
- Royal Brisbane and Women's Hospital, Metro North Hospital and Health Service, Brisbane, QLD, 4029, Australia
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4102, Australia
| | - Jane Sun
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4102, Australia
| | - Imaan A Ahmed
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4102, Australia
| | - Felicia Phua
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4102, Australia
| | - Gustavo R Rossi
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4102, Australia
| | - Cheng-Yu Lin
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4102, Australia
| | | | - Ernst J Wolvetang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jason Brown
- Herston Biofabrication Institute, Metro North Hospital and Health Service, Brisbane, QLD, 4029, Australia
- Royal Brisbane and Women's Hospital, Metro North Hospital and Health Service, Brisbane, QLD, 4029, Australia
| | - Kiarash Khosrotehrani
- Herston Biofabrication Institute, Metro North Hospital and Health Service, Brisbane, QLD, 4029, Australia
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, QLD, 4102, Australia
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Heiligenstein X, Lucas MS. One for All, All for One: A Close Look at In-Resin Fluorescence Protocols for CLEM. Front Cell Dev Biol 2022; 10:866472. [PMID: 35846358 PMCID: PMC9280628 DOI: 10.3389/fcell.2022.866472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Sample preparation is the novel bottleneck for high throughput correlative light and electron microscopy (CLEM). Protocols suitable for both imaging methods must therefore balance the requirements of each technique. For fluorescence light microscopy, a structure of interest can be targeted using: 1) staining, which is often structure or tissue specific rather than protein specific, 2) dye-coupled proteins or antibodies, or 3) genetically encoded fluorescent proteins. Each of these three methods has its own advantages. For ultrastructural investigation by electron microscopy (EM) resin embedding remains a significant sample preparation approach, as it stabilizes the sample such that it withstands the vacuum conditions of the EM, and enables long-term storage. Traditionally, samples are treated with heavy metal salts prior to resin embedding, in order to increase imaging contrast for EM. This is particularly important for volume EM (vEM) techniques. Yet, commonly used contrasting agents (e.g., osmium tetroxide, uranyl acetate) tend to impair fluorescence. The discovery that fluorescence can be preserved in resin-embedded specimens after mild heavy metal staining was a game changer for CLEM. These so-called in-resin fluorescence protocols present a significant leap forward for CLEM approaches towards high precision localization of a fluorescent signal in (volume) EM data. Integrated microscopy approaches, combining LM and EM detection into a single instrument certainly require such an “all in one” sample preparation. Preserving, or adding, dedicated fluorescence prior to resin embedding requires a compromise, which often comes at the expense of EM imaging contrast and membrane visibility. Especially vEM can be strongly hampered by a lack of heavy metal contrasting. This review critically reflects upon the fundamental aspects of resin embedding with regard to 1) specimen fixation and the physics and chemistry underlying the preservation of protein structure with respect to fluorescence and antigenicity, 2) optimization of EM contrast for transmission or scanning EM, and 3) the choice of embedding resin. On this basis, various existing workflows employing in-resin fluorescence are described, highlighting their common features, discussing advantages and disadvantages of the respective approach, and finally concluding with promising future developments for in-resin CLEM.
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Affiliation(s)
| | - Miriam S. Lucas
- Scientific Center for Light and Electron Microscopy (ScopeM), ETH Zurich, Zurich, Switzerland
- *Correspondence: Miriam S. Lucas,
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