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Wadkin LE, Makarenko I, Parker NG, Shukurov A, Figueiredo FC, Lako M. Human Stem Cells for Ophthalmology: Recent Advances in Diagnostic Image Analysis and Computational Modelling. CURRENT STEM CELL REPORTS 2023; 9:57-66. [PMID: 38145008 PMCID: PMC10739444 DOI: 10.1007/s40778-023-00229-0] [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] [Accepted: 11/07/2023] [Indexed: 12/26/2023]
Abstract
Purpose of Review To explore the advances and future research directions in image analysis and computational modelling of human stem cells (hSCs) for ophthalmological applications. Recent Findings hSCs hold great potential in ocular regenerative medicine due to their application in cell-based therapies and in disease modelling and drug discovery using state-of-the-art 2D and 3D organoid models. However, a deeper characterisation of their complex, multi-scale properties is required to optimise their translation to clinical practice. Image analysis combined with computational modelling is a powerful tool to explore mechanisms of hSC behaviour and aid clinical diagnosis and therapy. Summary Many computational models draw on a variety of techniques, often blending continuum and discrete approaches, and have been used to describe cell differentiation and self-organisation. Machine learning tools are having a significant impact in model development and improving image classification processes for clinical diagnosis and treatment and will be the focus of much future research.
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Affiliation(s)
- L. E. Wadkin
- School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, UK
| | - I. Makarenko
- School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, UK
| | - N. G. Parker
- School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, UK
| | - A. Shukurov
- School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, UK
| | - F. C. Figueiredo
- Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - M. Lako
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
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2
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Kim MH, Thanuthanakhun N, Kino-Oka M. Novel strategy to improve hepatocyte differentiation stability through synchronized behavior-driven mechanical memory of iPSCs. Biotechnol Bioeng 2023; 120:593-607. [PMID: 36369977 DOI: 10.1002/bit.28285] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/27/2022] [Accepted: 11/10/2022] [Indexed: 11/15/2022]
Abstract
Cellular homeostasis is assumed to be regulated by the coordination of dynamic behaviors. Lack of efficient methods for synchronizing large quantities of cells makes studying cell culture strategies for bioprocess development challenging. Here, we demonstrate a novel application of botulinum hemagglutinin (HA), an E-cadherin function-blocking agent, to synchronize behavior-driven mechanical memory in human induced pluripotent stem cell (hiPSC) cultures. Application of HA to hiPSCs resulted in a decrease in actin bundling and disruption of colony formation in a concentration-and time-dependent manner. Interestingly, cytoskeleton rearrangement in cells with prolonged exposure to HA resulted in mechanical memory synchronization with Yes-associated protein, which increased pluripotent cell homogeneity. Synchronized hiPSCs have higher capability to differentiate into functional hepatocytes than unsynchronized hiPSCs, resulting in improved efficiency and robustness of hepatocyte differentiation. Thus, our strategy for cell behavior synchronization before differentiation induction provides an approach against the instability of differentiation of pluripotent cells.
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Affiliation(s)
- Mee-Hae Kim
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
| | - Naruchit Thanuthanakhun
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
| | - Masahiro Kino-Oka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan.,Research Base for Cell Manufacturability, Osaka University, Suita, Osaka, Japan
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3
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Lin CY, Ching YY, Wu SF, Lee YK, Fan HC, Su LY, Tsai SY, Chen YC, Shen CI, Su HL. Coating-Free Culture Medium for Establishing and Maintaining Human Induced Pluripotent Stem Cells. Cell Transplant 2023; 32:9636897231198172. [PMID: 37698258 PMCID: PMC10498698 DOI: 10.1177/09636897231198172] [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: 05/01/2023] [Revised: 08/11/2023] [Accepted: 08/15/2023] [Indexed: 09/13/2023] Open
Abstract
Cell expansion of human pluripotent stem cells (hPSCs) commonly depends on Matrigel as a coating matrix on two-dimensional (2D) culture plates and 3D microcarriers. However, the xenogenic Matrigel requires sophisticated quality-assurance processes to meet clinical requirements. In this study, we develop an innovative coating-free medium for expanding hPSCs. The xenofree medium supports the weekend-free culture and competitive growth of hPSCs on several cell culture plastics without an additional pre-coating process. The pluripotent stemness of the expanded cells is stably sustained for more than 10 passages, featured with high pluripotent marker expressions, normal karyotyping, and differentiating capacity for three germ layers. The expression levels of some integrins are reduced, compared with those of the hPSCs on Matrigel. This medium also successfully supports the clonal expansion and induced pluripotent stem cell establishment from mitochondrial-defective MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) patient's peripheral blood mononuclear cells. This innovative hPSC medium provides a straightforward scale-up process for producing clinical-orientated hPSCs by excluding the conventional coating procedure.
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Affiliation(s)
- Chih-Yao Lin
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Yu-Yun Ching
- Duogenic StemCells Corporation, Taichung, Taiwan
| | - Shih-Fang Wu
- The Joint Program of Tissue Engineering and Regenerative Medicine, National Chung Hsing University and National Health Research Institutes, Taichung, Taiwan
| | - Yi-Ko Lee
- Duogenic StemCells Corporation, Taichung, Taiwan
| | - Hueng-Chuen Fan
- Department of Pediatrics, Tungs’ Taichung MetroHarbor Hospital, Wuchi, Taichung, Taiwan
- Department of Nursing, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli, Taiwan
| | - Liang-Yu Su
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Su-Yi Tsai
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Yu-Ching Chen
- The Joint Program of Tissue Engineering and Regenerative Medicine, National Chung Hsing University and National Health Research Institutes, Taichung, Taiwan
- Department of Obstetrics and Gynecology, Changhua Christian Hospital, Changhua City, Taiwan
| | - Ching-I Shen
- Duogenic StemCells Corporation, Taichung, Taiwan
| | - Hong-Lin Su
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan
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4
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Thanuthanakhun N, Kim MH, Kino-oka M. Cell Behavioral Dynamics as a Cue in Optimizing Culture Stabilization in the Bioprocessing of Pluripotent Stem Cells. Bioengineering (Basel) 2022; 9:669. [PMID: 36354580 PMCID: PMC9687444 DOI: 10.3390/bioengineering9110669] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 10/28/2022] [Accepted: 11/05/2022] [Indexed: 04/23/2024] Open
Abstract
Pluripotent stem cells (PSCs) are important for future regenerative medicine therapies. However, in the production of PSCs and derivatives, the control of culture-induced fluctuations in the outcome of cell quality remains challenging. A detailed mechanistic understanding of how PSC behaviors are altered in response to biomechanical microenvironments within a culture is necessary for rational bioprocessing optimization. In this review, we discuss recent insights into the role of cell behavioral and mechanical homeostasis in modulating the states and functions of PSCs during culture processes. We delineate promising ways to manipulate the culture variability through regulating cell behaviors using currently developed tools. Furthermore, we anticipate their potential implementation for designing a culture strategy based on the concept of Waddington's epigenetic landscape that may provide a feasible solution for tuning the culture quality and stability in the bioprocessing space.
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Affiliation(s)
- Naruchit Thanuthanakhun
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Osaka, Japan
| | - Mee-Hae Kim
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Osaka, Japan
| | - Masahiro Kino-oka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Osaka, Japan
- Research Base for Cell Manufacturability, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Osaka, Japan
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5
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Sonoi R, Hagihara Y. Quantitative understanding of HepaRG cells during drug-induced intrahepatic cholestasis through changes in bile canaliculi dynamics. Pharmacol Res Perspect 2022; 10:e00960. [PMID: 35621230 PMCID: PMC9137115 DOI: 10.1002/prp2.960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/18/2022] [Indexed: 11/09/2022] Open
Abstract
An understanding of the quantitative relationship between bile canaliculus (BC) dynamics and the disruption of tight junctions (TJs) during drug-induced intrahepatic cholestasis may lead to new strategies aimed at drug development and toxicity testing. To investigate the relationship between BC dynamics and TJ disruption, we retrospectively analyzed the extent of TJ disruption in response to changes in the dynamics of BCs cultured with entacapone (ENT). Three hours after adding ENT, the ZO-1-negative BC surface area ratio became significantly higher (4.1-fold) than those of ZO-1-positive BCs. Based on these data, we calculated slopes of surface area changes, m, of each ZO-1-positive and ZO-1-negative BC. BCs with m ≤ 15 that fell within the 95% confidence interval of ZO-1-positive BCs were defined as ZO-1-positive. To validate this method, we compared the frequency of ZO-1-positive BCs, FZ , with that of BCs with m ≤ 15, FT , in culture using drugs that regulate TJ, or induce intrahepatic cholestasis. FT values were correlated with FZ under all culture conditions (R2 = .99). Our results indicate that the magnitude of BC surface area changes is a factor affecting TJ disruption, suggesting that maintaining TJ integrity by slowing BC dilation inhibits cell death.
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Affiliation(s)
- Rie Sonoi
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka, Japan
| | - Yoshihisa Hagihara
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ikeda, Osaka, Japan
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6
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Kim MH, Kino-Oka M. Mechanobiological conceptual framework for assessing stem cell bioprocess effectiveness. Biotechnol Bioeng 2021; 118:4537-4549. [PMID: 34460101 DOI: 10.1002/bit.27929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/22/2021] [Accepted: 08/27/2021] [Indexed: 12/12/2022]
Abstract
Fully realizing the enormous potential of stem cells requires developing efficient bioprocesses and optimizations founded in mechanobiological considerations. Here, we emphasize the importance of mechanotransduction as one of the governing principles of stem cell bioprocesses, underscoring the need to further explore the behavioral mechanisms involved in sensing mechanical cues and coordinating transcriptional responses. We identify the sources of intrinsic, extrinsic, and external noise in bioprocesses requiring further study, and discuss the criteria and indicators that may be used to assess and predict cell-to-cell variability resulting from environmental fluctuations. Specifically, we propose a conceptual framework to explain the impact of mechanical forces within the cellular environment, identify key cell state determinants in bioprocesses, and discuss downstream implementation challenges.
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Affiliation(s)
- Mee-Hae Kim
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Masahiro Kino-Oka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan
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7
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Hirose T, Kotoku J, Toki F, Nishimura EK, Nanba D. Label-free quality control and identification of human keratinocyte stem cells by deep learning-based automated cell tracking. Stem Cells 2021; 39:1091-1100. [PMID: 33783921 PMCID: PMC8359832 DOI: 10.1002/stem.3371] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/23/2021] [Indexed: 01/07/2023]
Abstract
Stem cell-based products have clinical and industrial applications. Thus, there is a need to develop quality control methods to standardize stem cell manufacturing. Here, we report a deep learning-based automated cell tracking (DeepACT) technology for noninvasive quality control and identification of cultured human stem cells. The combination of deep learning-based cascading cell detection and Kalman filter algorithm-based tracking successfully tracked the individual cells within the densely packed human epidermal keratinocyte colonies in the phase-contrast images of the culture. DeepACT rapidly analyzed the motion of individual keratinocytes, which enabled the quantitative evaluation of keratinocyte dynamics in response to changes in culture conditions. Furthermore, DeepACT can distinguish keratinocyte stem cell colonies from non-stem cell-derived colonies by analyzing the spatial and velocity information of cells. This system can be widely applied to stem cell cultures used in regenerative medicine and provides a platform for developing reliable and noninvasive quality control technology.
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Affiliation(s)
- Takuya Hirose
- Graduate School of Medical Care and Technology, Teikyo University, Tokyo, Japan
| | - Jun'ichi Kotoku
- Graduate School of Medical Care and Technology, Teikyo University, Tokyo, Japan
| | - Fujio Toki
- Department of Stem Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Emi K Nishimura
- Department of Stem Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.,Division of Aging and Regeneration, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Daisuke Nanba
- Department of Stem Cell Biology, Medical Research Institute, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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Wadkin LE, Orozco-Fuentes S, Neganova I, Lako M, Barrio RA, Baggaley AW, Parker NG, Shukurov A. OCT4 expression in human embryonic stem cells: spatio-temporal dynamics and fate transitions. Phys Biol 2021; 18:026003. [PMID: 33296887 DOI: 10.1088/1478-3975/abd22b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The improved in vitro regulation of human embryonic stem cell (hESC) pluripotency and differentiation trajectories is required for their promising clinical applications. The temporal and spatial quantification of the molecular interactions controlling pluripotency is also necessary for the development of successful mathematical and computational models. Here we use time-lapse experimental data of OCT4-mCherry fluorescence intensity to quantify the temporal and spatial dynamics of the pluripotency transcription factor OCT4 in a growing hESC colony in the presence and absence of BMP4. We characterise the internal self-regulation of OCT4 using the Hurst exponent and autocorrelation analysis, quantify the intra-cellular fluctuations and consider the diffusive nature of OCT4 evolution for individual cells and pairs of their descendants. We find that OCT4 abundance in the daughter cells fluctuates sub-diffusively, showing anti-persistent self-regulation. We obtain the stationary probability distributions governing hESC transitions amongst the different cell states and establish the times at which pro-fate cells (which later give rise to pluripotent or differentiated cells) cluster in the colony. By quantifying the similarities between the OCT4 expression amongst neighbouring cells, we show that hESCs express similar OCT4 to cells within their local neighbourhood within the first two days of the experiment and before BMP4 treatment. Our framework allows us to quantify the relevant properties of proliferating hESC colonies and the procedure is widely applicable to other transcription factors and cell populations.
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Affiliation(s)
- L E Wadkin
- School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne, United Kingdom
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9
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Nguyen TNT, Sasaki K, Kino-Oka M. Development of a kinetic model expressing anomalous phenomena in human induced pluripotent stem cell culture. J Biosci Bioeng 2020; 131:305-313. [PMID: 33262019 DOI: 10.1016/j.jbiosc.2020.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/20/2020] [Accepted: 10/28/2020] [Indexed: 11/24/2022]
Abstract
During culture with feeder cells, deviation from the undifferentiated state of human induced pluripotent stem cells (hiPSCs) occurs at a very low frequency. Anomalous cell migration in central and peripheral regions of hiPSC colonies has been suggested to be the trigger for this phenomenon. To confirm this hypothesis, sequential cell migration prior to deviation must be demonstrated. This has been difficult using in vitro methods. We therefore developed a kinetic model with a proposed definition of anomalous cell migration as continuous relatively fast or slow cell migration. The developed model was validated via in silico reproduction of deviation phenomenon observed in vitro, such as the positions of deviated cells in a colony and the frequency of deviation in culture. This model suggests that anomalous cell migration-driven hiPSC deviation can be explained by two factors: a mechanical stimulus, represented by cell migration, and duration of the mechanical stimulus. The factor "duration of mechanical stimulus" sets our model apart from others, and helps to realize the ultra-rare trigger (approximately 10-5) of deviation from the undifferentiated state in hiPSC culture.
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Affiliation(s)
- Thi Nhu Trang Nguyen
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kei Sasaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan; Global Center for Medical Engineering and Informatics, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Masahiro Kino-Oka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
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10
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The recent advances in the mathematical modelling of human pluripotent stem cells. SN APPLIED SCIENCES 2020; 2:276. [PMID: 32803125 PMCID: PMC7391994 DOI: 10.1007/s42452-020-2070-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 01/17/2020] [Indexed: 12/20/2022] Open
Abstract
Human pluripotent stem cells hold great promise for developments in regenerative medicine and drug design. The mathematical modelling of stem cells and their properties is necessary to understand and quantify key behaviours and develop non-invasive prognostic modelling tools to assist in the optimisation of laboratory experiments. Here, the recent advances in the mathematical modelling of hPSCs are discussed, including cell kinematics, cell proliferation and colony formation, and pluripotency and differentiation.
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Kim MH, Kino-Oka M. Bioengineering Considerations for a Nurturing Way to Enhance Scalable Expansion of Human Pluripotent Stem Cells. Biotechnol J 2020; 15:e1900314. [PMID: 31904180 DOI: 10.1002/biot.201900314] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 11/11/2019] [Indexed: 12/13/2022]
Abstract
Understanding how defects in mechanotransduction affect cell-to-cell variability will add to the fundamental knowledge of human pluripotent stem cell (hPSC) culture, and may suggest new approaches for achieving a robust, reproducible, and scalable process that result in consistent product quality and yields. Here, the current state of the understanding of the fundamental mechanisms that govern the growth kinetics of hPSCs between static and dynamic cultures is reviewed, the factors causing fluctuations are identified, and culture strategies that might eliminate or minimize the occurrence of cell-to-cell variability arising from these fluctuations are discussed. The existing challenges in the development of hPSC expansion methods for enabling the transition from process development to large-scale production are addressed, a mandatory step for industrial and clinical applications of hPSCs.
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Affiliation(s)
- Mee-Hae Kim
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masahiro Kino-Oka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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12
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Nguyen TNT, Sasaki K, Kino-oka M. Elucidation of human induced pluripotent stem cell behaviors in colonies based on a kinetic model. J Biosci Bioeng 2019; 127:625-632. [DOI: 10.1016/j.jbiosc.2018.10.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/13/2018] [Accepted: 10/18/2018] [Indexed: 02/06/2023]
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13
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Maintenance of an undifferentiated state of human-induced pluripotent stem cells through botulinum hemagglutinin-mediated regulation of cell behavior. J Biosci Bioeng 2019; 127:744-751. [PMID: 30660482 DOI: 10.1016/j.jbiosc.2018.11.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 11/14/2018] [Accepted: 11/29/2018] [Indexed: 01/01/2023]
Abstract
Applications of human induced pluripotent stem cell (hiPSC) culture are impaired by problems with long term maintenance of pluripotency. In this study, we report that exposure to botulinum hemagglutinin (HA), an E-cadherin function-blocking agent, suppressed deviation from an undifferentiated state in hiPSC colonies. Time-lapse imaging of live cells revealed that cells in central regions of colonies moved slowly and underwent a morphological change to a cobblestone-like shape via interaction between contacting cells, forming dense, multiple layers. Staining and migration analysis showed that actin stress fibers and paxillin spots were diminished in colony central regions, and this was associated with alteration of cellular morphology and migratory behavior. However, in culture with HA exposure, cells in the central and peripheral regions of hiPSC colonies were migratory and arranged in loose monolayers, resulting in relatively uniform dispersion of cells in colonies. We also found that a well-organized network of actin stress fibers was of significance in the central and peripheral regions of a colony, resulting in activation of paxillin and E-cadherin expression in hiPSCs. After routine application of HA for serial passages, hiPSCs remained pluripotent and capable of differentiating into all three germ layers. These observations indicate that relaxation of cell-cell junctions by HA induced rearrangements of the cytoskeleton and cell adhesion in hiPSC colonies by promoting migratory behaviors. These results suggest that this simple and readily reproducible culture strategy is a potentially useful tool for improving the robust and scalable maintenance of undifferentiated hiPSC cultures.
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