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Shibuya K, Watanabe M, Goto R, Zaitsu M, Ganchiku Y, Taketomi A. The Efficacy of the Hepatocyte Spheroids for Hepatocyte Transplantation. Cell Transplant 2021; 30:9636897211000014. [PMID: 33900126 PMCID: PMC8085376 DOI: 10.1177/09636897211000014] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The safety and short-term efficacy of hepatocyte transplantation (HCTx) have been widely proven. However, issues such as reduced viability and/or function of hepatocytes, insufficient engraftment, and lack of a long-term effect have to be overcome for widespread application of HCTx. In this study, we evaluated hepatocyte spheroids (HSs), formed by self-aggregation of hepatocytes, as an alternative to hepatocytes in single-cell suspension. Hepatocytes were isolated from C57BL/6 J mice liver using a three-step collagenase perfusion technique and HSs were formed by the hanging drop method. After the spheroids formation, the HSs showed significantly higher mRNA expression of albumin, ornithine transcarbamylase, glucose-6-phosphate, alpha-1-antitrypsin, low density lipoprotein receptor, coagulation factors, and apolipoprotein E (ApoE) than 2 dimensional (2D)-cultured hepatocytes (p < 0.05). Albumin production by HSs was significantly higher than that by 2D-cultured hepatocytes (9.5 ± 2.5 vs 3.5 ± 1.8 μg/dL, p < 0.05). The HSs, but not single hepatocytes, maintained viability and albumin mRNA expression in suspension (92.0 ± 2.8% and 1.03 ± 0.09 at 6 h). HSs (3.6 × 106 cells) or isolated hepatocytes (fSH, 3.6 × 106 cells) were transplanted into the liver of ApoE knockout (KO-/-) mice via the portal vein. Following transplantation, serum ApoE concentration (ng/mL) of HS-transplanted mice (1w: 63.1 ± 56.7, 4w: 17.0 ± 10.9) was higher than that of fSH-transplanted mice (1 w: 33.4 ± 13.0, 4w: 13.7 ± 9.6). In both groups, the mRNA levels of pro-inflammatory cytokines (IL-6, IL-1β, TNF-α, MCP-1, and MIP-1β) were upregulated in the liver following transplantation; however, no significant differences were observed. Pathologically, transplanted HSs were observed as flat cell clusters in contact with the portal vein wall on day 7. Additionally, ApoE positive cells were observed in the liver parenchyma distant from the portal vein on day 28. Our results indicate that HS is a promising alternative to single hepatocytes and can be applied for HCTx.
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Affiliation(s)
- Kazuaki Shibuya
- Department of Gastroenterological surgery I, 12810Hokkaido university graduate school, kita-ku, Sapporo, Japan
| | - Masaaki Watanabe
- Transplant surgery, 163693Hokkaido University Hospital, kita-ku, Sapporo, Japan
| | - Ryoichi Goto
- Department of Gastroenterological surgery I, 12810Hokkaido university graduate school, kita-ku, Sapporo, Japan
| | - Masaaki Zaitsu
- Department of Gastroenterological surgery I, 12810Hokkaido university graduate school, kita-ku, Sapporo, Japan
| | - Yoshikazu Ganchiku
- Department of Gastroenterological surgery I, 12810Hokkaido university graduate school, kita-ku, Sapporo, Japan
| | - Akinobu Taketomi
- Department of Gastroenterological surgery I, 12810Hokkaido university graduate school, kita-ku, Sapporo, Japan
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Chen Y, Nguyen DT, Kokil GR, Wong YX, Dang TT. Microencapsulated islet-like microtissues with toroid geometry for enhanced cellular viability. Acta Biomater 2019; 97:260-271. [PMID: 31404714 DOI: 10.1016/j.actbio.2019.08.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 08/08/2019] [Accepted: 08/08/2019] [Indexed: 12/27/2022]
Abstract
Transplantation of immuno-isolated islets is a promising strategy to restore insulin-secreting function in patients with Type 1 diabetes. However, the clinical translation of this treatment approach remains elusive due to the loss of islet viability resulting from hypoxia at the avascular transplantation site. To address this challenge, we designed non-spherical islet-like microtissues and investigated the effect of their geometries on cellular viability. Insulin-secreting microtissues with different shapes were fabricated by assembly of monodispersed rat insulinoma beta cells on micromolded nonadhesive hydrogels. Our study quantitatively demonstrated that toroid microtissues exhibited enhanced cellular viability and metabolic activity compared to rod and spheroid microtissues with the same volume. At a similar level of cellular viability, toroid geometry facilitated efficient packing of more cells into each microtissue than rod and spheroid geometries. In addition, toroid microtissues maintained the characteristic glucose-responsive insulin secretion of rat insulinoma beta cells. Furthermore, toroid microtissues preserved their geometry and structural integrity following their microencapsulation in immuno-isolatory alginate hydrogel. Our study suggests that adopting toroid geometry in designing therapeutic microtissues potentially reduces mass loss of cellular grafts and thereby may improve the performance of transplanted islets towards a clinically viable cure for Type 1 diabetes. STATEMENT OF SIGNIFICANCE: Transplantation of therapeutic cells is a promising strategy for the treatment of a wide range of hormone or protein-deficiency diseases. However, the clinical application of this approach is hindered by the loss of cell viability and function at the avascular transplantation site. To address this challenge, we fabricated hydrogel-encapsulated islet-like microtissues with non-spheroidal geometry and optimal surface-to-volume ratio. This study demonstrated that the viability of therapeutic cells can be significantly increased solely by redesigning the microtissue configuration without requiring any additional biochemical or operational accessories. This study suggests that the adoption of toroid geometry provides a possible avenue to improve the long-term survival of transplanted therapeutic cells and expedite the translation of cell-based therapy towards clinical application.
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Affiliation(s)
- Yang Chen
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
| | - Dang T Nguyen
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
| | - Ganesh R Kokil
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
| | - Yun Xuan Wong
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore
| | - Tram T Dang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637459, Singapore.
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Murrow LM, Weber RJ, Gartner ZJ. Dissecting the stem cell niche with organoid models: an engineering-based approach. Development 2017; 144:998-1007. [PMID: 28292846 PMCID: PMC5358107 DOI: 10.1242/dev.140905] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
For many tissues, single resident stem cells grown in vitro under appropriate three-dimensional conditions can produce outgrowths known as organoids. These tissues recapitulate much of the cell composition and architecture of the in vivo organ from which they derive, including the formation of a stem cell niche. This has facilitated the systematic experimental manipulation and single-cell, high-throughput imaging of stem cells within their respective niches. Furthermore, emerging technologies now make it possible to engineer organoids from purified cellular and extracellular components to directly model and test stem cell-niche interactions. In this Review, we discuss how organoids have been used to identify and characterize stem cell-niche interactions and uncover new niche components, focusing on three adult-derived organoid systems. We also describe new approaches to reconstitute organoids from purified cellular components, and discuss how this technology can help to address fundamental questions about the adult stem cell niche.
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Affiliation(s)
- Lyndsay M Murrow
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Box 2280, San Francisco, CA 94158, USA
| | - Robert J Weber
- Graduate Program in Chemistry and Chemical Biology, University of California at San Francisco, San Francisco, CA 94158, USA
| | - Zev J Gartner
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th Street, Box 2280, San Francisco, CA 94158, USA
- Graduate Program in Chemistry and Chemical Biology, University of California at San Francisco, San Francisco, CA 94158, USA
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Wang K, Wang X, Han C, Hou W, Wang J, Chen L, Luo Y. From Micro to Macro: The Hierarchical Design in a Micropatterned Scaffold for Cell Assembling and Transplantation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29. [PMID: 28066985 DOI: 10.1002/adma.201604600] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 09/21/2016] [Indexed: 05/09/2023]
Abstract
A microwell-patterned membranous scaffold that integrates nano- and microscale topographical characteristics based on polyurethane is fabricated for transplanting syngeneic islets and allogeneic mesenchymal stem cells into diabetic rodents. The scaffold effectively allows for assembling of single cells/microtissues, enables the transplantation of cells with spatial control, and improves the transplant's engraftment efficacy in vivo for treating diabetes.
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Affiliation(s)
- Kai Wang
- Department of Biomedical Engineering, Peking University, Beijing, 100871, China
| | - Xi Wang
- Department of Biomedical Engineering, Peking University, Beijing, 100871, China
| | - Chengsheng Han
- Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Wenda Hou
- Department of Biomedical Engineering, Peking University, Beijing, 100871, China
| | - Jinyang Wang
- Department of Biomedical Engineering, Peking University, Beijing, 100871, China
| | - Liangyi Chen
- Institute of Molecular Medicine, Peking University, Beijing, 100871, China
| | - Ying Luo
- Department of Biomedical Engineering, Peking University, Beijing, 100871, China
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Chowanadisai W, Messerli SM, Miller DH, Medina JE, Hamilton JW, Messerli MA, Brodsky AS. Cisplatin Resistant Spheroids Model Clinically Relevant Survival Mechanisms in Ovarian Tumors. PLoS One 2016; 11:e0151089. [PMID: 26986722 PMCID: PMC4795743 DOI: 10.1371/journal.pone.0151089] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 02/23/2016] [Indexed: 12/31/2022] Open
Abstract
The majority of ovarian tumors eventually recur in a drug resistant form. Using cisplatin sensitive and resistant cell lines assembled into 3D spheroids we profiled gene expression and identified candidate mechanisms and biological pathways associated with cisplatin resistance. OVCAR-8 human ovarian carcinoma cells were exposed to sub-lethal concentrations of cisplatin to create a matched cisplatin-resistant cell line, OVCAR-8R. Genome-wide gene expression profiling of sensitive and resistant ovarian cancer spheroids identified 3,331 significantly differentially expressed probesets coding for 3,139 distinct protein-coding genes (Fc >2, FDR < 0.05) (S2 Table). Despite significant expression changes in some transporters including MDR1, cisplatin resistance was not associated with differences in intracellular cisplatin concentration. Cisplatin resistant cells were significantly enriched for a mesenchymal gene expression signature. OVCAR-8R resistance derived gene sets were significantly more biased to patients with shorter survival. From the most differentially expressed genes, we derived a 17-gene expression signature that identifies ovarian cancer patients with shorter overall survival in three independent datasets. We propose that the use of cisplatin resistant cell lines in 3D spheroid models is a viable approach to gain insight into resistance mechanisms relevant to ovarian tumors in patients. Our data support the emerging concept that ovarian cancers can acquire drug resistance through an epithelial-to-mesenchymal transition.
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Affiliation(s)
- Winyoo Chowanadisai
- Department of Nutritional Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America, 74078
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America, 02543
| | - Shanta M. Messerli
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America, 02543
| | - Daniel H. Miller
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America, 02139
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America, 02142
| | - Jamie E. Medina
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America, 02543
- Department of Biological Sciences, Bridgewater State University, Bridgewater, Massachusetts, United States of America, 02325
| | - Joshua W. Hamilton
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America, 02543
- Swenson College of Science and Engineering, University of Minnesota, Duluth, Minnesota, United States of America, 55804
| | - Mark A. Messerli
- Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America, 02543
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, United States of America, 57007
- * E-mail: (MAM); (ASB)
| | - Alexander S. Brodsky
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America, 02139
- Department of Pathology and Laboratory Medicine, Rhode Island Hospital and Alpert Medical School of Brown University, Providence, Rhode Island, United States of America, 02903
- Center for Computational Molecular Biology, Brown University, Providence, Rhode Island, United States of America, 02912
- * E-mail: (MAM); (ASB)
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Naik N, Caves J, Chaikof E, Allen MG. Generation of spatially aligned collagen fiber networks through microtransfer molding. Adv Healthc Mater 2014; 3:367-74. [PMID: 24039146 PMCID: PMC3938984 DOI: 10.1002/adhm.201300112] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2013] [Revised: 06/01/2013] [Indexed: 11/05/2022]
Abstract
The unique biomechanical properties of native tissue are governed by the organization and composition of integrated collagen and elastin networks. An approach for fabricating spatially aligned, fiber-reinforced composites with adjustable collagen fiber dimensions, layouts, and distribution within an elastin-like protein matrix yielding a biocomposite with controllable mechanical responses is reported. Microtransfer molding is employed for the fabrication of hollow and solid collagen fibers with straight or crimped fiber geometries. Collagen fibers (width: 2-50 μm, thickness: 300 nm to 3 μm) exhibit a Young's modulus of 126 ± 61 MPa and an ultimate tensile strength of 7 ± 3.2 MPa. As fiber networks within composite structures, straight fiber layouts display orthotropic responses with Young's modulus ranging from 0.95 ± 0.35 to 10.4 ± 0.5 MPa and tensile strength from 0.22 ± 0.08 to 0.87 ± 0.5 MPa with increasing fraction of collagen fibers (1-10%, v/v). In contrast, composites based on crimped fiber layouts exhibit strain-dependent stiffness with an increase in Young's modulus from 0.7 ± 0.14 MPa to 3.15 ± 0.49 MPa, at a specific transition strain. Through controlling the microstructure of engineered collagen fiber networks, a facile means is established to control macroscale mechanical responses of composite protein-based materials.
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Affiliation(s)
- Nisarga Naik
- Department of Surgery, Harvard Medical School, Beth Israel Deaconess Medical Center Boston, MA 02115, USA, Wyss Institute of Biologically Inspired Engineering of Harvard University Boston, MA 02115, USA, School of Electrical and Computer Engineering, Georgia Institute of Technology Atlanta, GA 30332, USA
| | - Jeffrey Caves
- Department of Surgery, Harvard Medical School, Beth Israel Deaconess Medical Center Boston, MA 02115, USA, Wyss Institute of Biologically Inspired Engineering of Harvard University Boston, MA 02115, USA
| | - Elliot Chaikof
- Department of Surgery, Harvard Medical School, Beth Israel Deaconess Medical Center Boston, MA 02115, USA, Wyss Institute of Biologically Inspired Engineering of Harvard University Boston, MA 02115, USA, Harvard Stem Cell Institute Boston, MA 02115, USA
| | - Mark G. Allen
- School of Electrical and Computer Engineering, Georgia Institute of Technology Atlanta, GA 30332, USA
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Jiang L, Liu J, Wang K, Gu X, Luo Y. Investigating design principles of micropatterned encapsulation systems containing high-density microtissue arrays. SCIENCE CHINA-LIFE SCIENCES 2014; 57:221-31. [PMID: 24435251 DOI: 10.1007/s11427-014-4609-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 10/12/2013] [Indexed: 12/24/2022]
Abstract
Immunoisolation is an important strategy to protect transplanted cells from rejection by the host immune system. Recently, microfabrication techniques have been used to create hydrogel membranes to encapsulate microtissue in an arrayed organization. The method illustrates a new macroencapsulation paradigm that may allow transplantation of a large number of cells with microscale spatial control, while maintaining an encapsulation device that is easily maneuverable and remaining integrated following transplantation. This study aims to investigate the design principles that relate to the translational application of micropatterned encapsulation membranes, namely, the control over the transplantation density/quantity of arrayed microtissues and the fidelity of pre-formed microtissues to micropatterns. Agarose hydrogel membranes with microwell patterns were used as a model encapsulation system to exemplify these principles. Our results show that high-density micropatterns can be generated in hydrogel membranes, which can potentially maximize the percentage volume of cellular content and thereby the transplantation efficiency of the encapsulation device. Direct seeding of microtissues demonstrates that microwell structures can efficiently position and organize pre-formed microtissues, suggesting the capability of micropatterned devices for manipulation of cellular transplants at multicellular or tissue levels. Detailed theoretical analysis was performed to provide insights into the relationship between micropatterns and the transplantation capacity of membrane-based encapsulation. Our study lays the ground for developing new macroencapsulation systems with microscale cellular/tissue patterns for regenerative transplantation.
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Affiliation(s)
- LiYang Jiang
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
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8
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9
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Liu JS, Gartner ZJ. Directing the assembly of spatially organized multicomponent tissues from the bottom up. Trends Cell Biol 2012; 22:683-91. [PMID: 23067679 PMCID: PMC3505240 DOI: 10.1016/j.tcb.2012.09.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 09/02/2012] [Accepted: 09/10/2012] [Indexed: 12/21/2022]
Abstract
The complexity of the human body derives from numerous modular building blocks assembled hierarchically across multiple length scales. These building blocks, spanning sizes ranging from single cells to organs, interact to regulate development and normal organismal function but become disorganized during disease. Here, we review methods for the bottom-up and directed assembly of modular, multicellular, and tissue-like constructs in vitro. These engineered tissues will help refine our understanding of the relationship between form and function in the human body, provide new models for the breakdown in tissue architecture that accompanies disease, and serve as building blocks for the field of regenerative medicine.
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Affiliation(s)
- Jennifer S Liu
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 95108, USA
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10
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Patel RS, Chang A, Lysaght MJ, Morgan JR. Control of the timing and dosage of IGF-I delivery from encapsulated cells. J Tissue Eng Regen Med 2012; 7:470-8. [PMID: 22319007 DOI: 10.1002/term.546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 07/21/2011] [Accepted: 11/14/2011] [Indexed: 11/09/2022]
Abstract
We report here on the development and characterization of a cell-based system for the regulated delivery of bioactive insulin-like growth factor I (IGF-I). A stable mammalian cell line, CHO-K1 Tet-IGFI, was genetically modified to have tetracycline-induced transcription of the human IGF-I gene. Cells were activated to express IGF-I in the presence of doxycycline (DOX), a tetracycline derivative, while expression was inactivated in the absence of DOX. Temporal, or on-off, release of IGF-I from cells encapsulated within Ca²⁺-alginate hydrogels was demonstrated in a pilot study over the course of 10 days in culture. Released growth factor was bioactive, exhibiting a proliferative effect comparable to recombinant purified IGF-I protein. The dosage levels and temporal control of IGF-I release from encapsulated cells meet the requirements of orthopedic wound repair, making this approach an attractive means for the controlled synthesis and delivery of growth factors in situ for wound healing.
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Affiliation(s)
- Roshni S Patel
- Center for Biomedical Engineering, Brown University, 171 Meeting Street, Providence, Rhode Island 02906, USA.
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Bao BA, Lai CP, Naus CC, Morgan JR. Pannexin1 drives multicellular aggregate compaction via a signaling cascade that remodels the actin cytoskeleton. J Biol Chem 2012; 287:8407-16. [PMID: 22267745 DOI: 10.1074/jbc.m111.306522] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pannexin 1 (Panx1) is a novel gap junction protein shown to have tumor-suppressive properties. To model its in vivo role in the intratumor biomechanical environment, we investigated whether Panx1 channels modulate the dynamic assembly of multicellular C6 glioma aggregates. Treatment with carbenoxolone and probenecid, which directly and specifically block Panx1 channels, respectively, showed that Panx1 is involved in accelerating aggregate assembly. Experiments further showed that exogenous ATP can reverse the inhibitive effects of carbenoxolone and that aggregate compaction is sensitive to the purinergic antagonist suramin. With a close examination of the F-actin microfilament network, these findings show that Panx1 channels act as conduits for ATP release that stimulate the P(2)X(7) purinergic receptor pathway, in turn up-regulating actomyosin function. Using a unique three-dimensional scaffold-free method to quantify multicellular interactions, this study shows that Panx1 is intimately involved in regulating intercellular biomechanical interactions pivotal in the progression of cancer.
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Affiliation(s)
- Brian A Bao
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Center for Biomedical Engineering, Brown University, Providence, Rhode Island 02912, USA
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12
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Kachouie NN, Du Y, Bae H, Khabiry M, Ahari AF, Zamanian B, Fukuda J, Khademhosseini A. Directed assembly of cell-laden hydrogels for engineering functional tissues. Organogenesis 2011; 6:234-44. [PMID: 21220962 DOI: 10.4161/org.6.4.12650] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Tissue engineering aims to develop functionalized tissues for organ replacement or restoration. Biodegradable scaffolds have been used in tissue engineering to support cell growth and maintain mechanical and biological properties of tissue constructs. Ideally cells on these scaffolds adhere, proliferate, and deposit matrix at a rate that is consistent with scaffold degradation. However, the cellular rearrangement within these scaffolds often does not recapitulate the architecture of the native tissues. Directed assembly of tissue-like structures is an attractive alternative to scaffold-based approach for tissue engineering which potentially can build tissue constructs with biomimetic architecture and function. In directed assembly, shape-controlled microstructures are fabricated in which organized structures of different cell types can be used as tissue building blocks. To fabricate tissue building blocks, hydrogels are commonly used as biomaterials for cell encapsulation to mimic the matrix in vivo. The hydrogel-based tissue building blocks can be arranged in pre-defined architectures by various directed tissue assembly techniques. In this paper, recent advances in directed assembly-based tissue engineering are summarized as an emerging alternative to meet challenges associated with scaffold-based tissue engineering and future directions are addressed.
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Affiliation(s)
- Nezamoddin N Kachouie
- Center for Biomedical Engineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, MA, USA
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Abstract
Recapitulating the elegant structures formed during development is an extreme synthetic and biological challenge. Great progress has been made in developing materials to support transplanted cells, yet the complexity of tissues is far beyond that found in even the most advanced scaffolds. Self-assembly is a motif used in development and a route for the production of complex materials. Self-assembly of peptides, proteins and other molecules at the nanoscale is promising, but in addition, intriguing ideas are emerging for self-assembly of micron-scale structures. In this brief review, very recent advances in the assembly of micron-scale cell aggregates and microgels will be described and discussed.
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Raof NA, Padgen MR, Gracias AR, Bergkvist M, Xie Y. One-dimensional self-assembly of mouse embryonic stem cells using an array of hydrogel microstrands. Biomaterials 2011; 32:4498-505. [PMID: 21459438 DOI: 10.1016/j.biomaterials.2011.03.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 03/07/2011] [Indexed: 02/07/2023]
Abstract
The ability of embryonic stem (ES) cells to self-renew indefinitely and to differentiate into multiple cell lineages holds promise for advances in modeling disease progression, screening drugs and treating diseases. To realize these potentials, it is imperative to study self-assembly in an embryonic microenvironment, as this may increase our understanding of ES cell maintenance and differentiation. In this study, we synthesized an array of one-dimensional alginate gel microstrands and aqueous microstrands through an SU-8 filter device by means of capillary action. Furthermore, we investigated self-assembly behaviors and differentiation potentials of mouse ES cells cultured in microstrands of varying diameters. We found that microstrands with an aqueous interior facilitated high density cell culture and formed compact microtissue structures, while microstrands with gelled interiors promote smaller cell aggregate structures. In particular, we noticed that ES cells collected from one-dimensional aqueous microstrands favored the differentiation towards cell lineages of endoderm and mesoderm, whereas those from gelled microstrands preferred to differentiate into ectoderm and mesoderm lineages. In addition to providing a "liquid-like" tubular microenvironment to understand one-dimensional self-assembly process of ES cells, this alginate hydrogel microstrand system also offers an alternative way to manipulate the stem cell fate-decision using bioengineered microenvironments.
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Affiliation(s)
- Nurazhani Abdul Raof
- College of Nanoscale Science and Engineering, University at Albany, State University of New York (SUNY), Albany, NY 12203, USA
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Bao B, Jiang J, Yanase T, Nishi Y, Morgan JR. Connexon-mediated cell adhesion drives microtissue self-assembly. FASEB J 2010; 25:255-64. [PMID: 20876208 DOI: 10.1096/fj.10-155291] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Microtissue self-assembly is thought to be driven primarily by cadherins, while connexons have been examined mainly in intercellular coupling. We investigated whether connexon 43 (Cx43)-mediated cell adhesion modulates self-assembly of human KGN granulosa cells, normal human fibroblasts (NHFs), and MCF-7 breast cancer cells seeded into nonadhesive agarose gels. We found that treatment with anti-Cx43 E2 (112 μg/ml), which suppresses Cx43 docking, significantly inhibited the kinetics of KGN and NHF self-assembly compared to the preimmune sera control (41.1 ± 4.5 and 24.5 ± 10.4% at 8 h, respectively). Likewise, gap junction inhibitor carbenoxolone also inhibited self-assembly of KGN, NHF, and MCF-7 cells in a dose-dependent manner that was specific to cell type. In contrast, Gap26 connexin mimetic peptide, which inhibits channel permeability but not docking, accelerated self-assembly of KGN and NHF microtissues. Experiments using selective enzymatic digestion of cell adhesion molecules and neutralizing N-cadherin antibodies further showed that self-assembly was comparably disrupted by inhibiting connexin- and cadherin-mediated adhesion. These findings demonstrate that connexon-mediated cell adhesion and intercellular communication differentially influence microtissue self-assembly, and that their contributions are comparable to those of cadherins.
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Affiliation(s)
- Brian Bao
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Center for Biomedical Engineering, Brown University, Providence, RI 02912, USA
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