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Chooi WH, Wu Y, Ng SY. Defined hydrogels for spinal cord organoids: challenges and potential applications. Neural Regen Res 2024; 19:2329-2330. [PMID: 38526259 PMCID: PMC11090425 DOI: 10.4103/nrr.nrr-d-23-01665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/07/2023] [Accepted: 12/26/2023] [Indexed: 03/26/2024] Open
Affiliation(s)
- Wai Hon Chooi
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Yuewen Wu
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore, Singapore
| | - Shi-Yan Ng
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
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2
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Kwokdinata C, Ramanujam V, Chen J, Nunes de Oliveira P, Nai MH, Chooi WH, Lim CT, Ng SY, David L, Chew SY. Correction to "Encapsulation of Human Spinal Cord Progenitor Cells in Hyaluronan-Gelatin Hydrogel for Spinal Cord Injury Treatment". ACS Appl Mater Interfaces 2024. [PMID: 38679863 DOI: 10.1021/acsami.4c06545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
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3
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Nguyen TD, Chooi WH, Jeon H, Chen J, Tan J, Roxby DN, Lee CYP, Ng SY, Chew SY, Han J. Label-Free and High-Throughput Removal of Residual Undifferentiated Cells From iPSC-Derived Spinal Cord Progenitor Cells. Stem Cells Transl Med 2024; 13:387-398. [PMID: 38321361 PMCID: PMC11016845 DOI: 10.1093/stcltm/szae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 12/06/2023] [Indexed: 02/08/2024] Open
Abstract
The transplantation of spinal cord progenitor cells (SCPCs) derived from human-induced pluripotent stem cells (iPSCs) has beneficial effects in treating spinal cord injury (SCI). However, the presence of residual undifferentiated iPSCs among their differentiated progeny poses a high risk as these cells can develop teratomas or other types of tumors post-transplantation. Despite the need to remove these residual undifferentiated iPSCs, no specific surface markers can identify them for subsequent removal. By profiling the size of SCPCs after a 10-day differentiation process, we found that the large-sized group contains significantly more cells expressing pluripotent markers. In this study, we used a sized-based, label-free separation using an inertial microfluidic-based device to remove tumor-risk cells. The device can reduce the number of undifferentiated cells from an SCPC population with high throughput (ie, >3 million cells/minute) without affecting cell viability and functions. The sorted cells were verified with immunofluorescence staining, flow cytometry analysis, and colony culture assay. We demonstrated the capabilities of our technology to reduce the percentage of OCT4-positive cells. Our technology has great potential for the "downstream processing" of cell manufacturing workflow, ensuring better quality and safety of transplanted cells.
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Affiliation(s)
- Tan Dai Nguyen
- Critical Analytics for Manufacturing of Personalized Medicine IRG, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| | - Wai Hon Chooi
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Hyungkook Jeon
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Manufacturing Systems and Design Engineering, Seoul National University of Science and Technology, Seoul, The Republic of Korea
| | - Jiahui Chen
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, Singapore
| | - Jerome Tan
- Critical Analytics for Manufacturing of Personalized Medicine IRG, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, Singapore
- NTU Institute for Health Technologies, Interdisciplinary Graduate Programme, Nanyang Technological University, Singapore, Singapore
| | - Daniel N Roxby
- Critical Analytics for Manufacturing of Personalized Medicine IRG, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, Singapore
| | - Cheryl Yi-Pin Lee
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Shi-Yan Ng
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Sing Yian Chew
- Critical Analytics for Manufacturing of Personalized Medicine IRG, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Jongyoon Han
- Critical Analytics for Manufacturing of Personalized Medicine IRG, Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
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Kwokdinata C, Ramanujam V, Chen J, de Oliveira PN, Nai MH, Chooi WH, Lim CT, Ng SY, David L, Chew SY. Encapsulation of Human Spinal Cord Progenitor Cells in Hyaluronan-Gelatin Hydrogel for Spinal Cord Injury Treatment. ACS Appl Mater Interfaces 2023; 15:50679-50692. [PMID: 37751213 DOI: 10.1021/acsami.3c07419] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Transplanting human induced pluripotent stem cells (iPSCs)-derived spinal cord progenitor cells (SCPCs) is a promising approach to treat spinal cord injuries. However, stem cell therapies face challenges in cell survival, cell localization to the targeted site, and the control of cell differentiation. Here, we encapsulated SCPCs in thiol-modified hyaluronan-gelatin hydrogels and optimized scaffold mechanical properties and cell encapsulation density to promote cell viability and neuronal differentiation in vitro and in vivo. Different compositions of hyaluronan-gelatin hydrogels formulated by varying concentrations of poly(ethylene glycol) diacrylate were mechanically characterized by using atomic force microscopy. In vitro SCPC encapsulation study showed higher cell viability and proliferation with lower substrate Young's modulus (200 Pa vs 580 Pa) and cell density. Moreover, the soft hydrogels facilitated a higher degree of neuronal differentiation with extended filament structures in contrast to clumped cellular morphologies obtained in stiff hydrogels (p < 0.01). When transplanted in vivo, the optimized SCPC-encapsulated hydrogels resulted in higher cell survival and localization at the transplanted region as compared to cell delivery without hydrogel encapsulation at 2 weeks postimplantation within the rat spinal cord (p < 0.01). Notably, immunostaining demonstrated that the hydrogel-encapsulated SCPCs differentiated along the neuronal and oligodendroglial lineages in vivo. The lack of pluripotency and proliferation also supported the safety of the SCPC transplantation approach. Overall, the injectable hyaluronan-gelatin hydrogel shows promise in supporting the survival and neural differentiation of human SCPCs after transplantation into the spinal cord.
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Affiliation(s)
- Christy Kwokdinata
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459, Singapore
| | - Vaibavi Ramanujam
- CNRS@CREATE, Create Tower #08-01, 1 Create Way, Singapore 138602, Singapore
| | - Jiahui Chen
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459, Singapore
| | | | - Mui Hoon Nai
- Department of Biomedical Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Wai Hon Chooi
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Republic of Singapore
| | - Chwee Teck Lim
- Department of Biomedical Engineering, National University of Singapore, Singapore 117576, Singapore
- Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore
| | - Shi Yan Ng
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Republic of Singapore
| | - Laurent David
- CNRS@CREATE, Create Tower #08-01, 1 Create Way, Singapore 138602, Singapore
- Ingénierie des Matériaux Polymères IMP UMR 5223, CNRS, Université Claude Bernard Lyon 1, INSA de Lyon, Université Jean Monnet, Université de Lyon, Villeurbanne F69622, France
| | - Sing Yian Chew
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
- School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
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Lee CYP, Chooi WH, Ng SY, Chew SY. Modulating neuroinflammation through molecular, cellular and biomaterial-based approaches to treat spinal cord injury. Bioeng Transl Med 2023; 8:e10389. [PMID: 36925680 PMCID: PMC10013833 DOI: 10.1002/btm2.10389] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/02/2022] [Accepted: 07/16/2022] [Indexed: 11/09/2022] Open
Abstract
The neuroinflammatory response that is elicited after spinal cord injury contributes to both tissue damage and reparative processes. The complex and dynamic cellular and molecular changes within the spinal cord microenvironment result in a functional imbalance of immune cells and their modulatory factors. To facilitate wound healing and repair, it is necessary to manipulate the immunological pathways during neuroinflammation to achieve successful therapeutic interventions. In this review, recent advancements and fresh perspectives on the consequences of neuroinflammation after SCI and modulation of the inflammatory responses through the use of molecular-, cellular-, and biomaterial-based therapies to promote tissue regeneration and functional recovery will be discussed.
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Affiliation(s)
- Cheryl Yi-Pin Lee
- Institute of Molecular and Cell Biology ASTAR Research Entities Singapore Singapore
| | - Wai Hon Chooi
- Institute of Molecular and Cell Biology ASTAR Research Entities Singapore Singapore
| | - Shi-Yan Ng
- Institute of Molecular and Cell Biology ASTAR Research Entities Singapore Singapore
| | - Sing Yian Chew
- School of Chemical and Biomedical Engineering Nanyang Technological University Singapore Singapore.,Lee Kong Chian School of Medicine Nanyang Technological University Singapore Singapore.,School of Materials Science and Engineering Nanyang Technological University Singapore Singapore
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Ow V, Chang JJ, Chooi WH, Boo YJ, Tan RPT, Wong JHM, Parikh BH, Su X, Ng SY, Loh XJ, Xue K. Orthogonally crosslinked alginate conjugate thermogels with potential for cell encapsulation. Carbohydr Polym 2023; 302:120308. [PMID: 36604036 DOI: 10.1016/j.carbpol.2022.120308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 10/18/2022] [Accepted: 11/01/2022] [Indexed: 11/25/2022]
Abstract
Hydrogels with more than one mode of crosslinking have gained interest due to improved control over hydrogel properties such as mechanical strength using multiple stimuli. In this work, sodium alginate was covalently conjugated onto thermoresponsive polyurethanes to prepare hybrid polymers (EPC-Alg) that are responsive to both temperature and Ca2+, forming orthogonally crosslinked hydrogels which are non-toxic to cells. Notably, the crosslinks are fully reversible, allowing for gel strength to be modulated via selective removal of either stimulus, or complete deconstruction of the hydrogel network by removing both stimuli. Higher alginate fractions increased the hydrophilicity and Ca2+ response of the EPC-Alg hydrogel, enabling tunable modulation of the thermal stability, stiffness and gelation temperatures. The EPC-Alg hydrogel could sustain protein release for a month and encapsulate neural spheroids with high cell viability after 7-day culture, demonstrating feasibility towards 3D cell encapsulation in cell-based biomedical applications such as cell encapsulation and cell therapy.
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Affiliation(s)
- Valerie Ow
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore; Department of Biomedical Engineering, National University of Singapore (NUS), 4 Engineering Drive 3, Singapore 117583, Singapore
| | - Jun Jie Chang
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore
| | - Wai Hon Chooi
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Yi Jian Boo
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore
| | - Rebekah P T Tan
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore
| | - Joey H M Wong
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore
| | - Bhav Harshad Parikh
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Xinyi Su
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore (NUS), 1E Kent Ridge Road, Singapore 119228, Singapore; Singapore Eye Research Institute (SERI), 20 College Rd, Singapore 169856, Singapore
| | - Shi Yan Ng
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Xian Jun Loh
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore; Department of Materials Science and Engineering, National University of Singapore (NUS), 9 Engineering Drive 1, Singapore 117575, Singapore; School of Materials Science and Engineering, Nanyang Technological University (NTU), 50 Nanyang Ave, Singapore 639798, Singapore.
| | - Kun Xue
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, Singapore 138634, Singapore.
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Chooi WH, Ng CY, Ow V, Harley J, Ng W, Hor JH, Low KE, Malleret B, Xue K, Ng SY. Defined Alginate Hydrogels Support Spinal Cord Organoid Derivation, Maturation, and Modeling of Spinal Cord Diseases. Adv Healthc Mater 2022; 12:e2202342. [PMID: 36502337 DOI: 10.1002/adhm.202202342] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/01/2022] [Indexed: 12/14/2022]
Abstract
In the process of generating organoids, basement membrane extracts or Matrigel are often used to encapsulate cells but they are poorly defined and contribute to reproducibility issues. While defined hydrogels are increasingly used for organoid culture, the effects of replacing Matrigel with a defined hydrogel on neural progenitor growth, neural differentiation, and maturation within organoids are not well-explored. In this study, the use of alginate hydrogels as a Matrigel substitute in spinal cord organoid generation is explored. It is found that alginate encapsulation reduces organoid size variability by preventing organoid aggregation. Importantly, alginate supports neurogenesis and gliogenesis of the spinal cord organoids at a similar efficiency to Matrigel, with mature myelinated neurons observed by day 120. Furthermore, using alginate leads to lower expression of non-spinal markers such as FOXA2, suggesting better control over neural fate specification. To demonstrate the feasibility of using alginate-based organoid cultures as disease models, an isogenic pair of induced pluripotent stem cells discordant for the ALS-causing mutation TDP43G298S is used, where increased TDP43 mislocalization in the mutant organoids is observed. This study shows that alginate is an ideal substitute for Matrigel for spinal cord organoid derivation, especially when a xeno-free and fully defined 3D culture condition is desired.
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Affiliation(s)
- Wai Hon Chooi
- Institute of Molecular and Cell Biology, A*STAR Research Entities, Singapore, 138673, Singapore
| | - Chong Yi Ng
- Institute of Molecular and Cell Biology, A*STAR Research Entities, Singapore, 138673, Singapore
| | - Valerie Ow
- Institute of Materials Research and Engineering, A*STAR Research Entities, Singapore, 138634, Singapore
| | - Jasmine Harley
- Institute of Molecular and Cell Biology, A*STAR Research Entities, Singapore, 138673, Singapore
| | - Winanto Ng
- Institute of Molecular and Cell Biology, A*STAR Research Entities, Singapore, 138673, Singapore
| | - Jin-Hui Hor
- Institute of Molecular and Cell Biology, A*STAR Research Entities, Singapore, 138673, Singapore
| | - Kay En Low
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore, 117597, Singapore
| | - Benoit Malleret
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore, 117597, Singapore.,Singapore Immunology Network, Singapore. Department of Microbiology and Immunology, Immunology Translational Research Program, A*STAR Research Entities, Singapore, 138648, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore, 117597, Singapore
| | - Kun Xue
- Institute of Materials Research and Engineering, A*STAR Research Entities, Singapore, 138634, Singapore
| | - Shi-Yan Ng
- Institute of Molecular and Cell Biology, A*STAR Research Entities, Singapore, 138673, Singapore
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Chooi WH, Dong Q, Low JZY, Yuen C, Chin JS, Lin J, Ong W, Liu Q, Chew SY. Cell Membrane-Coated Electrospun Fibers Enhance Keratinocyte Growth through Cell-Type Specific Interactions. ACS Appl Bio Mater 2021; 4:4079-4083. [DOI: 10.1021/acsabm.1c00303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Wai Hon Chooi
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore
| | - Quanbin Dong
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Jeremy Zhi Yan Low
- School of Biological Sciences, Nanyang Technological University, 637551 Singapore
| | - Clement Yuen
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore
| | - Jiah Shin Chin
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore
- NTU Institute of Health Technologies, Interdisciplinary Graduate School, Nanyang Technological University, 637533 Singapore
| | - Junquan Lin
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore
| | - William Ong
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore
- NTU Institute of Health Technologies, Interdisciplinary Graduate School, Nanyang Technological University, 637533 Singapore
| | - Quan Liu
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore
| | - Sing Yian Chew
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, 308232 Singapore
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Chooi WH, Chin JS, Chew SY. Scaffold-Based Delivery of CRISPR/Cas9 Ribonucleoproteins for Genome Editing. Methods Mol Biol 2021; 2211:183-191. [PMID: 33336278 DOI: 10.1007/978-1-0716-0943-9_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The simple and versatile CRISPR/Cas9 system is a promising strategy for genome editing in mammalian cells. Generally, the genome editing components, namely Cas9 protein and single-guide RNA (sgRNA), are delivered in the format of plasmids, mRNA, or ribonucleoprotein (RNP) complexes. In particular, non-viral approaches are desirable as they overcome the safety concerns posed by viral vectors. To control cell fate for tissue regeneration, scaffold-based delivery of genome editing components will offer a route for local delivery and provide possible synergistic effects with other factors such as topographical cues that are co-delivered by the same scaffold. In this chapter, we detail a simple method of surface modification to functionalize electrospun nanofibers with CRISPR/Cas9 RNP complexes. The mussel-inspired bio-adhesive coating will be used as it is a simple and effective method to immobilize biomolecules on the surface. Nanofibers will provide a biomimicking microenvironment and topographical cues to seeded cells. For evaluation, a model cell line with single copies of enhanced green fluorescent protein (U2OS.EGFP) will be used to validate the efficiency of gene disruption.
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Affiliation(s)
- Wai Hon Chooi
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jiah Shin Chin
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
- NTU Institute of Health Technologies, Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore
| | - Sing Yian Chew
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore.
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
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Lin J, Chooi WH, Ong W, Zhang N, Bechler ME, Ffrench-Constant C, Chew SY. Oriented and sustained protein expression on biomimicking electrospun fibers for evaluating functionality of cells. Mater Sci Eng C Mater Biol Appl 2020; 118:111407. [PMID: 33255010 DOI: 10.1016/j.msec.2020.111407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 11/25/2022]
Abstract
A proper protein orientation is often required in order to achieve specific protein-receptor interaction to elicit a desired biological response. Here, we present a Protein A-based biomimicking platform that is capable of efficiently orienting proteins for evaluating cellular behaviour. By absorbing Protein A onto aligned bio-mimicking polycaprolactone (PCL) fibers, we demonstrate that protein binding could be retained on these fibers for at least 7 days under physiologically relevant conditions. We further show that Protein A served as a molecular orientor to arrange the recombinant proteins in similar orientations. Such protein-orienting scaffolds were further verified to be biologically functional by using sensitive primary rat cortical neurons (CNs) and oligodendrocyte progenitor cells (OPCs), as model neural cells for a stringent proof of concept. Specifically, CNs that were seeded on fibers coated with Protein A and a known enhancer of neurite growth (L1 Cell Adhesion Molecular L1CAM) displayed the longest total neurite length (462.77 ± 100.79 μm, p < 0.001) as compared to the controls. Besides that, OPCs seeded on fibers coated with Protein A and Neuregulin-1 Type III (Nrg1 type III) (myelin enhancer) produced the longest myelin ensheathment length (19.8 ± 11.69 μm). These results demonstrate the efficacy of this platform for protein screening applications.
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Affiliation(s)
- Junquan Lin
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
| | - Wai Hon Chooi
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
| | - William Ong
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore; NTU Institute for Health Technologies (Health Tech NTU), Interdisciplinary Graduate School, Nanyang Technological University, Singapore 637533, Singapore
| | - Na Zhang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
| | - Marie E Bechler
- MRC-Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh EH164UU, UK
| | - Charles Ffrench-Constant
- MRC-Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh EH164UU, UK
| | - Sing Yian Chew
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore.
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Chooi WH, Ong W, Murray A, Lin J, Nizetic D, Chew SY. Correction: Scaffold mediated gene knockdown for neuronal differentiation of human neural progenitor cells. Biomater Sci 2019; 7:2623. [PMID: 31045191 DOI: 10.1039/c9bm90028d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Correction for 'Scaffold mediated gene knockdown for neuronal differentiation of human neural progenitor cells' by Wai Hon Chooi et al., Biomater. Sci., 2018, 6, 3019-3029.
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Affiliation(s)
- Wai Hon Chooi
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore. sychew.ntu.edu.sg
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Chin JS, Chooi WH, Wang H, Ong W, Leong KW, Chew SY. Scaffold-mediated non-viral delivery platform for CRISPR/Cas9-based genome editing. Acta Biomater 2019; 90:60-70. [PMID: 30978509 DOI: 10.1016/j.actbio.2019.04.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/29/2019] [Accepted: 04/08/2019] [Indexed: 01/22/2023]
Abstract
Genome editing, especially via the simple and versatile type II CRISPR/Cas9 system, offers an effective avenue to precisely control cell fate, an important aspect of tissue regeneration. Unfortunately, most CRISPR/Cas9 non-viral delivery strategies only utilise micro-/nano-particle delivery methods. While these approaches provide reasonable genomic editing efficiencies, their systemic delivery may lead to undesirable off-target effects. For in vivo applications, a more localized and sustained delivery approach may be useful, particularly in the context of tissue regeneration. Here, we developed a scaffold that delivers the CRISPR/Cas9 components (i.e. single guide RNA (sgRNA) and Cas9 protein complexes) in a localized and non-viral manner. Specifically, using mussel-inspired bioadhesive coating, polyDOPA-melanin (pDOPA), we adsorbed Cas9:sgRNA lipofectamine complexes onto bio-mimicking fiber scaffolds. To evaluate the genome-editing efficiency of this platform, U2OS.EGFP cells were used as the model cell type. pDOPA coating was essential in allowing Cas9:sgRNA lipofectamine complexes to adhere onto the scaffolds with a higher loading efficiency, while laminin coating was necessary for maintaining cell viability and proliferation on the pDOPA-coated fibers for effective gene editing (21.5% editing efficiency, p < 0.001). Importantly, U2OS.EGFP cells took up Cas9:sgRNA lipofectamine complexes directly from the scaffolds via reverse transfection. Overall, we demonstrate the efficacy of such fiber scaffolds in providing localized, sustained and non-viral delivery of Cas9:sgRNA complexes. Such genome editing scaffolds may find useful applications in tissue regeneration. STATEMENT OF SIGNIFICANCE: Currently, there is a lack of effective non-viral means to deliver CRISPR/Cas9 components for genome editing. Most existing approaches only utilize micro-/nano-particles by injection or systemic delivery, which may lead to undesirable off-target effects. Here, we report a platform that delivers the CRISPR/Cas9 components (i.e. single guide RNA (sgRNA) and Cas9 protein complexes) in a localized and sustained manner. We used mussel-inspired bioadhesive coating to functionalize the bio-mimicking fiber scaffolds with Cas9:sgRNA lipofectamine complexes, to allow effective gene editing for the cells seeded on the scaffolds. Importantly, the cells took up Cas9:sgRNA lipofectamine complexes directly from the scaffolds. Such genome editing scaffolds may find useful applications in tissue regeneration.
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Chooi WH, Ong W, Murray A, Lin J, Nizetic D, Chew SY. Scaffold mediated gene knockdown for neuronal differentiation of human neural progenitor cells. Biomater Sci 2018; 6:3019-3029. [PMID: 30277233 DOI: 10.1039/c8bm01034j] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The use of human induced pluripotent stem cell-derived neural progenitor cells (hiPSC-NPCs) is an attractive therapeutic option for damaged nerve tissues. To direct neuronal differentiation of stem cells, we have previously developed an electrospun polycaprolactone nanofiber scaffold that was functionalized with siRNA targeting Re-1 silencing transcription factor (REST), by mussel-inspired bioadhesive coating. However, the efficacy of nanofiber-mediated RNA interference on hiPSC-NPCs differentiation remains unknown. Furthermore, interaction between such cell-seeded scaffolds with injured tissues has not been tested. In this study, scaffolds were optimized for REST knockdown in hiPSC-NPCs to enhance neuronal differentiation. Specifically, the effects of two different mussel-inspired bioadhesives and transfection reagents were analyzed. Scaffolds functionalized with RNAiMAX Lipofectamine-siREST complexes enhanced the differentiation of hiPSC-NPCs into TUJ1+ cells (60% as compared to 22% in controls with scrambled siNEG after 9 days) without inducing high cytotoxicity. When cell-seeded scaffolds were transplanted to transected spinal cord organotypic slices, similar efficiency in neuronal differentiation was observed. The scaffolds also supported the migration of cells and neurite outgrowth from the spinal cord slices. Taken together, the results suggest that this scaffold can be effective in enhancing hiPSC-NPC neuronal commitment by gene-silencing for the treatment of injured spinal cords.
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Affiliation(s)
- Wai Hon Chooi
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore. sychew.ntu.edu.sg
| | - William Ong
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore. sychew.ntu.edu.sg
| | - Aoife Murray
- Lee Kong Chian School of Medicine, Nanyang Technological University, 308232 Singapore
| | - Junquan Lin
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore. sychew.ntu.edu.sg
| | - Dean Nizetic
- Lee Kong Chian School of Medicine, Nanyang Technological University, 308232 Singapore
| | - Sing Yian Chew
- School of Chemical & Biomedical Engineering, Nanyang Technological University, 637459 Singapore. sychew.ntu.edu.sg and Lee Kong Chian School of Medicine, Nanyang Technological University, 308232 Singapore
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Chooi WH, Chan SCW, Gantenbein B, Chan BP. Correction: Loading-Induced Heat-Shock Response in Bovine Intervertebral Disc Organ Culture. PLoS One 2016; 11:e0167406. [PMID: 27875587 PMCID: PMC5119852 DOI: 10.1371/journal.pone.0167406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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15
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Chooi WH, Chan SCW, Gantenbein B, Chan BP. Loading-Induced Heat-Shock Response in Bovine Intervertebral Disc Organ Culture. PLoS One 2016; 11:e0161615. [PMID: 27580124 PMCID: PMC5006975 DOI: 10.1371/journal.pone.0161615] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 08/09/2016] [Indexed: 12/22/2022] Open
Abstract
Mechanical loading has been shown to affect cell viability and matrix maintenance in the intervertebral disc (IVD) but there is no investigation on how cells survive mechanical stress and whether the IVD cells perceive mechanical loading as stress and respond by expression of heat shock proteins. This study investigates the stress response in the IVD in response to compressive loading. Bovine caudal disc organ culture was used to study the effect of physiological range static loading and dynamic loading. Cell activity, gene expression and immunofluorescence staining were used to analyze the cell response. Cell activity and cytoskeleton of the cells did not change significantly after loading. In gene expression analysis, significant up-regulation of heat shock protein-70 (HSP70) was observed in nucleus pulposus after two hours of loading. However, the expression of the matrix remodeling genes did not change significantly after loading. Similarly, expressions of stress response and matrix remodeling genes changed with application and removal of the dynamic loading. The results suggest that stress response was induced by physiological range loading without significantly changing cell activity and upregulating matrix remodeling. This study provides direct evidence on loading induced stress response in IVD cells and contributes to our understanding in the mechanoregulation of intervertebral disc cells.
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Affiliation(s)
- Wai Hon Chooi
- Tissue Engineering Laboratory, Department of Mechanical Engineering, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Samantha Chun Wai Chan
- Tissue & Organ Mechanobiology, Institute of Surgical Technology and Biomechanics, University of Bern, Bern, Switzerland.,Biointerfaces, Empa, Swiss Federal Laboratories for Materials Science and Technology, St Gallen, Switzerland
| | - Benjamin Gantenbein
- Tissue & Organ Mechanobiology, Institute of Surgical Technology and Biomechanics, University of Bern, Bern, Switzerland
| | - Barbara Pui Chan
- Tissue Engineering Laboratory, Department of Mechanical Engineering, The University of Hong Kong, Hong Kong Special Administrative Region, China
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16
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Chooi WH, Chan BP. Compression loading-induced stress responses in intervertebral disc cells encapsulated in 3D collagen constructs. Sci Rep 2016; 6:26449. [PMID: 27197886 PMCID: PMC4873809 DOI: 10.1038/srep26449] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 04/29/2016] [Indexed: 01/24/2023] Open
Abstract
Cells protect themselves from stresses through a cellular stress response. In the interverebral disc, such response was also demonstrated to be induced by various environmental stresses. However, whether compression loading will cause cellular stress response in the nucleus pulposus cells (NPCs) is not well studied. By using an in vitro collagen microencapsulation model, we investigated the effect of compression loading on the stress response of NPCs. Cell viability tests, and gene and protein expression experiments were conducted, with primers for the heat shock response (HSR: HSP70, HSF1, HSP27 and HSP90), and unfolded protein response (UPR: GRP78, GRP94, ATF4 and CHOP) genes and an antibody to HSP72. Different gene expression patterns occurred due to loading type throughout experiments. Increasing the loading strain for a short duration did not increase the stress response genes significantly, but over longer durations, HSP70 and HSP27 were upregulated. Longer loading durations also resulted in a continuous upregulation of HSR genes and downregulation of UPR genes, even after load removal. The rate of apoptosis did not increase significantly after loading, suggesting that stress response genes might play a role in cell survival following mechanical stress. These results demonstrate how mechanical stress might induce and control the expression of HSR and UPR genes in NPCs.
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Affiliation(s)
- Wai Hon Chooi
- Tissue Engineering Laboratory, Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region, China
| | - Barbara Pui Chan
- Tissue Engineering Laboratory, Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region, China
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17
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Chik TK, Chooi WH, Li YY, Ho FC, Cheng HW, Choy TH, Sze KY, Luk KKD, Cheung KMC, Chan BP. Spinal Implants: Bioengineering a Multicomponent Spinal Motion Segment Construct-A 3D Model for Complex Tissue Engineering (Adv. Healthcare Mater. 1/2015). Adv Healthc Mater 2015. [DOI: 10.1002/adhm.201570004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Tsz Kit Chik
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Wai Hon Chooi
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Yuk Yin Li
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Fu Chak Ho
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Hiu Wa Cheng
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Tsz Hang Choy
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Kam Yim Sze
- Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Keith Kei Dip Luk
- Department of Orthopaedics & Traumatology; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Kenneth Man Chi Cheung
- Department of Orthopaedics & Traumatology; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Barbara Pui Chan
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
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Chik TK, Chooi WH, Li YY, Ho FC, Cheng HW, Choy TH, Sze KY, Luk KKD, Cheung KMC, Chan BP. Bioengineering a multicomponent spinal motion segment construct--a 3D model for complex tissue engineering. Adv Healthc Mater 2015; 4:99-112. [PMID: 24846571 DOI: 10.1002/adhm.201400192] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Indexed: 01/28/2023]
Abstract
Intervertebral disc degeneration is an important clinical problem but existing treatments have significant drawbacks. The ability to bioengineer the entire spinal motion segment (SMS) offers hope for better motion preservation strategies but is extremely challenging. Here, fabrication of a multicomponent SMS construct with complex hierarchical organization from mesenchymal stem cells and collagen-based biomaterials, using a module-based integrative approach, is reported. The construct consists of two osteochondral subunits, a nucleus pulposus (NP-)-like core and a multi-lamellae annulus fibrosus (AF-)-like component. Chondrogenic medium is crucial for stabilizing the osteochondral subunits, which are shown to allow passive nutrient diffusion, while cyclic compression is necessary for better fiber matrix organization. Cells adhere, survive, and interact with the NP-like core. Cyclic torsional loading stimulates cell alignment in the AF-like lamellae and the number of lamellae affects the mechanical properties of the construct. This work represents an important milestone in SMS tissue engineering and provides a 3D model for studying tissue maturation and functional remodeling.
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Affiliation(s)
- Tsz Kit Chik
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Wai Hon Chooi
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Yuk Yin Li
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Fu Chak Ho
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Hiu Wa Cheng
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Tsz Hang Choy
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Kam Yim Sze
- Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Keith Kei Dip Luk
- Department of Orthopaedics & Traumatology; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Kenneth Man Chi Cheung
- Department of Orthopaedics & Traumatology; Li Ka Shing Faculty of Medicine; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
| | - Barbara Pui Chan
- Tissue Engineering Laboratory; Department of Mechanical Engineering; The University of Hong Kong; Pokfulam Road Hong Kong Special Administrative Region China
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Gan CW, Chooi WH, Ng HCA, Wong YS, Venkatraman SS, Lim LHY. Development of a novel biodegradable drug-eluting Ventilation tube for chronic otitis media with effusion. Laryngoscope 2013; 123:1770-7. [DOI: 10.1002/lary.23895] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/25/2012] [Indexed: 11/08/2022]
Affiliation(s)
- Chee Wee Gan
- Department of Otolaryngology-Head and Neck Surgery; National University of Singapore; Singapore
| | - Wai Hon Chooi
- Department of Otolaryngology-Head and Neck Surgery; National University of Singapore; Singapore
| | - Herr Cheun Anthony Ng
- School of Materials Science and Engineering; Nanyang Technological University; Singapore
| | - Yee Shan Wong
- School of Materials Science and Engineering; Nanyang Technological University; Singapore
| | - Subbu S. Venkatraman
- School of Materials Science and Engineering; Nanyang Technological University; Singapore
| | - Lynne Hsueh Yee Lim
- Department of Otolaryngology-Head and Neck Surgery; National University of Singapore; Singapore
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Varshney RR, Zhou R, Hao J, Yeo SS, Chooi WH, Fan J, Wang DA. Chondrogenesis of synovium-derived mesenchymal stem cells in gene-transferred co-culture system. Biomaterials 2010; 31:6876-91. [PMID: 20638976 DOI: 10.1016/j.biomaterials.2010.05.038] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 05/18/2010] [Indexed: 01/26/2023]
Abstract
A co-culture strategy has been developed in this study wherein rabbit synovial mesenchymal stem cells (SMSCs) are co-cultured with growth factor (GF) transfected articular chondrocytes. Toward this end, both SMSCs and early passage rabbit articular chondrocytes that had been adenovirally transduced with transforming growth factor-beta 3 (TGF-beta3) gene were separately encapsulated in alginate beads and co-cultured in the same pool of chondrogenic medium. The chondrocytes act as transfected companion cells (TCCs) providing GF supply to induce chondrogenic differentiation of SMSCs that play the role of therapeutic progenitor cells (TPCs). Against the same TCC based TGF-beta3 release profile, the co-culture was started at different time points (Day 0, Day 10 and Day 20) but made to last for identical periods of exposure (30 days) so that the exposure conditions could be optimized in terms of initiation and duration. Transfection of TCCs prevents the stem cell based TPCs from undergoing the invasive procedure. It also prevents unpredictable complications in the TPCs caused by long-term constitutive over-expression of a GF. The adenovirally transfected TCCs exhibit a transient GF expression which results in a timely termination of GF supply to the TPCs. The TCC-sourced transgenic TGF-beta3 successfully induced chondrogenesis in the TPCs. Real-time PCR results show enhanced expression of cartilage markers and immuno/histochemical staining for Glycosaminoglycans (GAG) and Collagen II also shows abundant extracellular matrix (ECM) production and chondrogenic morphogenesis in the co-cultured TPCs. These results confirm the efficacy of directing stem cell differentiation towards chondrogenesis and cartilage tissue formation by co-culturing them with GF transfected chondrocytes.
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Affiliation(s)
- Rohan R Varshney
- Division of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457, Singapore
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