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Li W, Guo J, Hobson EC, Xue X, Li Q, Fu J, Deng CX, Guo Z. Metabolic-Glycoengineering-Enabled Molecularly Specific Acoustic Tweezing Cytometry for Targeted Mechanical Stimulation of Cell Surface Sialoglycans. Angew Chem Int Ed Engl 2024; 63:e202401921. [PMID: 38498603 PMCID: PMC11073901 DOI: 10.1002/anie.202401921] [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: 01/27/2024] [Revised: 03/14/2024] [Accepted: 03/18/2024] [Indexed: 03/20/2024]
Abstract
In this study, we developed a novel type of dibenzocyclooctyne (DBCO)-functionalized microbubbles (MBs) and validated their attachment to azide-labelled sialoglycans on human pluripotent stem cells (hPSCs) generated by metabolic glycoengineering (MGE). This enabled the application of mechanical forces to sialoglycans on hPSCs through molecularly specific acoustic tweezing cytometry (mATC), that is, displacing sialoglycan-anchored MBs using ultrasound (US). It was shown that subjected to the acoustic radiation forces of US pulses, sialoglycan-anchored MBs exhibited significantly larger displacements and faster, more complete recovery after each pulse than integrin-anchored MBs, indicating that sialoglycans are more stretchable and elastic than integrins on hPSCs in response to mechanical force. Furthermore, stimulating sialoglycans on hPSCs using mATC reduced stage-specific embryonic antigen-3 (SSEA-3) and GD3 expression but not OCT4 and SOX2 nuclear localization. Conversely, stimulating integrins decreased OCT4 nuclear localization but not SSEA-3 and GD3 expression, suggesting that mechanically stimulating sialoglycans and integrins initiated distinctive mechanoresponses during the early stages of hPSC differentiation. Taken together, these results demonstrated that MGE-enabled mATC uncovered not only different mechanical properties of sialoglycans on hPSCs and integrins but also their different mechanoregulatory impacts on hPSC differentiation, validating MGE-based mATC as a new, powerful tool for investigating the roles of glycans and other cell surface biomolecules in mechanotransduction.
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Affiliation(s)
- Weiping Li
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jiatong Guo
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Eric C. Hobson
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xufeng Xue
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Qingjiang Li
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
- Department of Chemistry, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Jianping Fu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Cheri X. Deng
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
- UF Health Cancer Center, University of Florida, Gainesville, FL 32611, USA
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2
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Xu Z, Liu S, Xue X, Li W, Fu J, Deng CX. Rapid responses of human pluripotent stem cells to cyclic mechanical strains applied to integrin by acoustic tweezing cytometry. Sci Rep 2023; 13:18030. [PMID: 37865697 PMCID: PMC10590420 DOI: 10.1038/s41598-023-45397-5] [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: 07/03/2023] [Accepted: 10/19/2023] [Indexed: 10/23/2023] Open
Abstract
Acoustic tweezing cytometry (ATC) is an ultrasound-based biophysical technique that has shown the capability to promote differentiation of human pluripotent stem cells (hPSCs). This study systematically examined how hPSCs respond to cyclic mechanical strains applied by ATC via displacement of integrin-bound microbubbles (averaged diameter of 4.3 µm) using ultrasound pulses (acoustic pressure 0.034 MPa, center frequency 1.24 MHz and pulse repetition frequency 1 Hz). Our data show downregulation of pluripotency marker Octamer-binding transcription factor 4 (OCT4) by at least 10% and increased nuclear localization of Yes-associated protein (YAP) by almost 100% in hPSCs immediately after ATC application for as short as 1 min and 5 min respectively. Analysis of the movements of integrin-anchored microbubbles under ATC stimulations reveals different stages of viscoelastic characteristic behavior and increasing deformation of the integrin-cytoskeleton (CSK) linkage. The peak displacement of integrin-bound microbubbles increased from 1.45 ± 0.16 to 4.74 ± 0.67 μm as the duty cycle of ultrasound pulses increased from 5% to 50% or the duration of each ultrasound pulse increased from 0.05 to 0.5 s. Real-time tracking of integrin-bound microbubbles during ATC application detects high correlation of microbubble displacements with OCT4 downregulation in hPSCs. Together, our data showing fast downregulation of OCT4 in hPSCs in respond to ATC stimulations highlight the unique mechanosensitivity of hPSCs to integrin-targeted cyclic force/strain dependent on the pulse duration or duty cycle of ultrasound pulses, providing insights into the mechanism of ATC-induced accelerated differentiation of hPSCs.
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Affiliation(s)
- Zhaoyi Xu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Shiying Liu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Xufeng Xue
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Weiping Li
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jianping Fu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
| | - Cheri X Deng
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
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Topal T, Fan Z, Deng LY, Krebsbach PH, Deng CX. Integrin-Targeted Cyclic Forces Accelerate Neural Tube-Like Rosette Formation from Human Embryonic Stem Cells. ACTA ACUST UNITED AC 2020; 3:e1900064. [PMID: 32648720 DOI: 10.1002/adbi.201900064] [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: 03/11/2019] [Revised: 07/29/2019] [Indexed: 11/11/2022]
Abstract
Mechanical forces play important roles in human embryonic stem cell (hESC) differentiation. To investigate the impact of dynamic mechanical forces on neural induction of hESCs, this study employs acoustic tweezing cytometry (ATC) to apply cyclic forces/strains to hESCs by actuating integrin-bound microbubbles using ultrasound pulses. Accelerated neural induction of hESCs is demonstrated as the result of combined action of ATC and neural induction medium (NIM). Specifically, application of ATC for 30 min followed by culture in NIM upregulates neuroecdoderm markers Pax6 and Sox1 as early as 6 h after ATC, and induces neural tube-like rosette formation at 48 h after ATC. In contrast, no changes are observed in hESCs cultured in NIM without ATC treatment. In the absence of NIM, ATC application decreases Oct4, but does not increase Pax6 and Sox1 expression, nor does it induce neural rossette formation. The effects of ATC are abolished by inhibition of FAK, myosin activity, and RhoA/ROCK signaling. Taken together, the results reveal a synergistic action of ATC and NIM as an integrated mechanobiology mechanism that requires both integrin-targeted cyclic forces and chemical factors for accelerated neural induction of hESCs.
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Affiliation(s)
- Tuğba Topal
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Zhenzhen Fan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA
| | - Laura Y Deng
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Paul H Krebsbach
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA.,UCLA School of Dentistry, Los Angeles, CA, 90095, USA
| | - Cheri X Deng
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48105, USA.,Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
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4
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Qian W, Chen W. Probing Single-Cell Mechanical Allostasis Using Ultrasound Tweezers. Cell Mol Bioeng 2019; 12:415-427. [PMID: 31719924 DOI: 10.1007/s12195-019-00578-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 05/31/2019] [Indexed: 12/14/2022] Open
Abstract
Introduction In response to external stress, cells alter their morphology, metabolic activity, and functions to mechanically adapt to the dynamic, local environment through cell allostasis. To explore mechanotransduction in cellular allostasis, we applied an integrated micromechanical system that combines an 'ultrasound tweezers'-based mechanical stressor and a Förster resonance energy transfer (FRET)-based molecular force biosensor, termed "actinin-sstFRET," to monitor in situ single-cell allostasis in response to transient stimulation in real time. Methods The ultrasound tweezers utilize 1 Hz, 10-s transient ultrasound pulses to acoustically excite a lipid-encapsulated microbubble, which is bound to the cell membrane, and apply a pico- to nano-Newton range of forces to cells through an RGD-integrin linkage. The actinin-sstFRET molecular sensor, which engages the actin stress fibers in live cells, is used to map real-time actomyosin force dynamics over time. Then, the mechanosensitive behaviors were examined by profiling the dynamics in Ca2+ influx, actomyosin cytoskeleton (CSK) activity, and GTPase RhoA signaling to define a single-cell mechanical allostasis. Results By subjecting a 1 Hz, 10-s physical stress, single vascular smooth muscle cells (VSMCs) were observed to remodeled themselves in a biphasic mechanical allostatic manner within 30 min that caused them to adjust their contractility and actomyosin activities. The cellular machinery that underscores the vital role of CSK equilibrium in cellular mechanical allostasis, includes Ca2+ influx, remodeling of actomyosin CSK and contraction, and GTPase RhoA signaling. Mechanical allostasis was observed to be compromised in VSMCs from patients with type II diabetes mellitus (T2DM), which could potentiate an allostatic maladaptation. Conclusions By integrating tools that simultaneously permit localized mechanical perturbation and map actomyosin forces, we revealed distinct cellular mechanical allostasis profiles in our micromechanical system. Our findings of cell mechanical allostasis and maladaptation provide the potential for mechanophenotyping cells to reveal their pathogenic contexts and their biophysical mediators that underlie multi-etiological diseases such as diabetes, hypertension, or aging.
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Affiliation(s)
- Weiyi Qian
- Department of Mechanical and Aerospace Engineering, New York University, Brooklyn, NY 11201 USA
| | - Weiqiang Chen
- Department of Mechanical and Aerospace Engineering, New York University, Brooklyn, NY 11201 USA.,Department of Biomedical Engineering, New York University, Brooklyn, NY 11201 USA
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5
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Hong X, Rzeczycki PM, Keswani RK, Murashov MD, Fan Z, Deng CX, Rosania GR. Acoustic tweezing cytometry for mechanical phenotyping of macrophages and mechanopharmaceutical cytotripsy. Sci Rep 2019; 9:5702. [PMID: 30952950 PMCID: PMC6450871 DOI: 10.1038/s41598-019-42180-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/25/2019] [Indexed: 11/15/2022] Open
Abstract
Macrophages are immune cells responsible for tissue debridement and fighting infection. Clofazimine, an FDA-approved antibiotic, accumulates and precipitates as rod-shaped, crystal-like drug inclusions within macrophage lysosomes. Drug treatment as well as pathophysiological states could induce changes in macrophage mechanical property which in turn impact their phenotype and function. Here we report the use of acoustic tweezing cytometry as a new approach for in situ mechanical phenotyping of macrophages and for targeted macrophage cytotripsy. Acoustic tweezing cytometry applies ultrasound pulses to exert controlled forces to individual cells via integrin-bound microbubbles, enabling a creep test for measuring cellular mechanical property or inducing irreversible changes to the cells. Our results revealed that macrophages with crystal-like drug inclusions became significantly softer with higher cell compliance, and behaved more elastic with faster creep and recovery time constants. On the contrary, phagocytosis of solid polyethylene microbeads or treatment with soluble clofazimine rendered macrophages stiffer. Most notably, application of ultrasound pulses of longer duration and higher amplitude in ATC actuated the integrin-bound microbubbles to mobilize the crystal-like drug inclusions inside macrophages, turning the rod-shaped drug inclusions into intracellular microblender that effectively destructed the cells. This phenomenon of acoustic mechanopharmaceutical cytotripsy may be exploited for ultrasound activated, macrophage-directed drug release and delivery.
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Affiliation(s)
- Xiaowei Hong
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Phillip M Rzeczycki
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Rahul K Keswani
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Mikhail D Murashov
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Zhenzhen Fan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Cheri X Deng
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA. .,Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Gus R Rosania
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, MI, 48109, USA.
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Topal T, Hong X, Xue X, Fan Z, Kanetkar N, Nguyen JT, Fu J, Deng CX, Krebsbach PH. Acoustic Tweezing Cytometry Induces Rapid Initiation of Human Embryonic Stem Cell Differentiation. Sci Rep 2018; 8:12977. [PMID: 30154528 PMCID: PMC6113316 DOI: 10.1038/s41598-018-30939-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 08/08/2018] [Indexed: 02/05/2023] Open
Abstract
Mechanical forces play critical roles in influencing human embryonic stem cell (hESC) fate. However, it remains largely uncharacterized how local mechanical forces influence hESC behavior in vitro. Here, we used an ultrasound (US) technique, acoustic tweezing cytometry (ATC), to apply targeted cyclic subcellular forces to hESCs via integrin-bound microbubbles (MBs). We found that ATC-mediated cyclic forces applied for 30 min to hESCs near the edge of a colony induced immediate global responses throughout the colony, suggesting the importance of cell-cell connection in the mechanoresponsiveness of hESCs to ATC-applied forces. ATC application generated increased contractile force, enhanced calcium activity, as well as decreased expression of pluripotency transcription factors Oct4 and Nanog, leading to rapid initiation of hESC differentiation and characteristic epithelial-mesenchymal transition (EMT) events that depend on focal adhesion kinase (FAK) activation and cytoskeleton (CSK) tension. These results reveal a unique, rapid mechanoresponsiveness and community behavior of hESCs to integrin-targeted cyclic forces.
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Affiliation(s)
- Tuğba Topal
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, 48109, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Xiaowei Hong
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Xufeng Xue
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Zhenzhen Fan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Biomedical Engineering, Tianjin University, Tianjin, P.R. China
| | - Ninad Kanetkar
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Joe T Nguyen
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, 48109, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jianping Fu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Cheri X Deng
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA. .,Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Paul H Krebsbach
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA. .,Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, MI, 48109, USA. .,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA. .,Section of Periodontics, University of California, Los Angeles School of Dentistry, Los Angeles, CA, 90095, USA.
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7
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Rong N, Zhou H, Liu R, Wang Y, Fan Z. Ultrasound and microbubble mediated plasmid DNA uptake: A fast, global and multi-mechanisms involved process. J Control Release 2018; 273:40-50. [PMID: 29407677 DOI: 10.1016/j.jconrel.2018.01.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 01/02/2018] [Accepted: 01/16/2018] [Indexed: 11/17/2022]
Abstract
Ultrasound application combined with microbubbles has shown great potential for intracellular gene delivery. However, the fundamental mechanistic question of how plasmid DNA enters the intracellular space mediated by ultrasound and microbubble has not been fully explored and understood. The goal of this study is to unveil the detailed intracellular uptake process of plasmid DNA stimulated by ultrasound and microbubbles, uniquely highlighting the role of microbubbles play in this process. The usage of targeted microbubbles pinpointed the subcellular membrane site, where ultrasound exerted acoustic force onto the cell membrane. With the combination of high-speed video microscopy and 3D confocal fluorescence microscopy, we show the spatiotemporal correlation between the microbubble dynamics and intracellular plasmid DNA distribution. Two ultrasound modes (high pressure short pulse and low pressure long pulse) were chosen to trigger different plasmid DNA uptake routes. We found that reversible cell membrane disruption, induced by high pressure short pulse ultrasound, permitted plasmid DNA passage across cell membrane, but not in an exclusive way. Under both ultrasound modes, with or without cell membrane disruption, global plasmid DNA internalization, even nuclear-localization, was observed immediately post ultrasound application. Our results show that plasmid DNA uptake evoked by localized acoustically excited microbubbles is a fast (<2min), global (not limited to the site where microbubbles were attached), and multi-mechanisms involved process.
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Affiliation(s)
- Ning Rong
- Department of Biomedical Engineering, Tianjin University, Tianjin 300072, China
| | - Hao Zhou
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ruming Liu
- College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yan Wang
- Department of Biomedical Engineering, Tianjin University, Tianjin 300072, China
| | - Zhenzhen Fan
- Department of Biomedical Engineering, Tianjin University, Tianjin 300072, China; State Key Laboratory of Acoustics, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China.
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8
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Acoustic tweezing cytometry enhances osteogenesis of human mesenchymal stem cells through cytoskeletal contractility and YAP activation. Biomaterials 2017; 134:22-30. [PMID: 28453955 DOI: 10.1016/j.biomaterials.2017.04.039] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 04/17/2017] [Accepted: 04/21/2017] [Indexed: 01/07/2023]
Abstract
Human mesenchymal stem cells (hMSCs) have great potential for cell-based therapies for treating degenerative bone diseases. It is known that mechanical cues in the cell microenvironment play an important role in regulating osteogenic (bone) differentiation of hMSCs. However, mechanoregulation of lineage commitment of hMSCs in conventional two-dimensional (2D) monocultures or bioengineered three-dimensional (3D) tissue constructs remains suboptimal due to complex biomaterial design criteria for hMSC culture. In this study, we demonstrate the feasibility of a novel cell mechanics and mechanobiology tool, acoustic tweezing cytometry (ATC), for mechanical stimulation of hMSCs. ATC utilizes ultrasound (US) pulses to actuate functionalized lipid microbubbles (MBs) which are covalently attached to hMSCs via integrin binding to exert forces to the cells. ATC stimulation increases cytoskeletal contractility of hMSCs regardless of the cell area. Furthermore, ATC application rescues osteogenic differentiation of hMSCs in culture conditions that are intrinsically repressive for hMSC osteogenesis (e.g., soft cell culture surfaces). ATC application activates transcriptional regulator YAP to enhance hMSC osteogenesis. Our data further show that F-actin, myosin II, and RhoA/ROCK signaling functions upstream of YAP activity in mediating ATC-stimulated hMSC osteogenesis. With the capability of applying controlled dynamic mechanical stimuli to cells, ATC provides a powerful tool for mechanoregulation of stem cell behaviors in tissue engineering and regenerative medicine applications.
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Biological Effects of Culture Substrates on Human Pluripotent Stem Cells. Stem Cells Int 2016; 2016:5380560. [PMID: 27656216 PMCID: PMC5021488 DOI: 10.1155/2016/5380560] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 07/04/2016] [Indexed: 01/03/2023] Open
Abstract
In recent years, as human pluripotent stem cells (hPSCs) have been commonly cultured in feeder-free conditions, a number of cell culture substrates have been applied or developed. However, the functional roles of these substrates in maintaining hPSC self-renewal remain unclear. Here in this review, we summarize the types of these substrates and their effect on maintaining hPSC self-renewal. Endogenous extracellular matrix (ECM) protein expression has been shown to be crucial in maintaining hPSC self-renewal. These ECM molecules interact with integrin cell-surface receptors and transmit their cellular signaling. We discuss the possible effect of integrin-mediated signaling pathways on maintaining hPSC self-renewal. Activation of integrin-linked kinase (ILK), which transmits ECM-integrin signaling to AKT (also known as protein kinase B), has been shown to be critical in maintaining hPSC self-renewal. Also, since naïve pluripotency has been widely recognized as an alternative pluripotent state of hPSCs, we discuss the possible effects of culture substrates and integrin signaling on naïve hPSCs based on the studies of mouse embryonic stem cells. Understanding the role of culture substrates in hPSC self-renewal and differentiation enables us to control hPSC behavior precisely and to establish scalable or microfabricated culture technologies for regenerative medicine and drug development.
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10
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Liu AP. Biophysical Tools for Cellular and Subcellular Mechanical Actuation of Cell Signaling. Biophys J 2016; 111:1112-1118. [PMID: 27456131 DOI: 10.1016/j.bpj.2016.02.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/17/2016] [Accepted: 02/01/2016] [Indexed: 10/24/2022] Open
Abstract
The ability to spatially control cell signaling can help resolve fundamental biological questions. Optogenetic and chemical dimerization techniques along with fluorescent biosensors to report cell signaling activities have enabled researchers to both visualize and perturb biochemistry in living cells. A number of approaches based on mechanical actuation using force-field gradients have emerged as complementary technologies to manipulate cell signaling in real time. This review covers several technologies, including optical, magnetic, and acoustic control of cell signaling and behavior and highlights some studies that have led to novel insights. I will also discuss some future direction on repurposing mechanosensitive channel for mechanical actuation of spatial cell signaling.
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Affiliation(s)
- Allen P Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan; Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan; Biophysics Program, University of Michigan, Ann Arbor, Michigan.
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