1
|
Xu X, Feng Q, Ma X, Deng Y, Zhang K, Ooi HS, Yang B, Zhang ZY, Feng B, Bian L. Dynamic gelatin-based hydrogels promote the proliferation and self-renewal of embryonic stem cells in long-term 3D culture. Biomaterials 2022; 289:121802. [PMID: 36152514 DOI: 10.1016/j.biomaterials.2022.121802] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/12/2022] [Accepted: 09/09/2022] [Indexed: 11/02/2022]
Abstract
Long-term maintenance of embryonic stem cells (ESCs) in the undifferentiated state is still challenging. Compared with traditional 2D culture methods, 3D culture in biomaterials such as hydrogels is expected to better support the long-term self-renewal of ESCs by emulating the biophysical and biochemical properties of the extracellular matrix (ECM). Although prior studies showed that soft and degradable hydrogels favor the 3D growth of ESCs, few studies have examined the impact of the structural dynamics of the hydrogel matrix on ESC behaviors. Herein, we report a gelatin-based structurally dynamic hydrogel (GelCD hydrogel) that emulates the intrinsic structural dynamics of the ECM. Compared with covalently crosslinked gelatin hydrogels (GelMA hydrogels) with similar stiffness and biodegradability, GelCD hydrogels significantly promote the clonal expansion and viability of encapsulated mouse ESCs (mESCs) independent of MMP-mediated hydrogel degradation. Furthermore, GelCD hydrogels better maintain the pluripotency of encapsulated mESCs than do traditional 2D culture methods that use MEF feeder cells or medium supplementation with GSK3β and MEK 1/2 inhibitors (2i). When cultured in GelCD hydrogels for an extended period (over 2 months) with cell passaging every 7 days, mESCs preserve their normal morphology and maintain their pluripotency and full differentiation capability. Our findings highlight the critical role of the structural dynamics of the hydrogel matrix in accommodating the volume expansion that occurs during clonal ESC growth, and we believe that our dynamic hydrogels represent a valuable tool to support the long-term 3D culture of ESCs.
Collapse
Affiliation(s)
- Xiayi Xu
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, 999077, China.
| | - Qian Feng
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400044, China; Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing, Chongqing, 400044, China
| | - Xun Ma
- Center for Regenerative Medicine and Health, Hong Kong Institute of Science and Innovation, Chinese Academy of Sciences Limited, Hong Kong SAR, 999077, China; School of Biomedical Sciences, Faculty of Medicine, Institute for Tissue Engineering and Regenerative Medicine (iTERM), CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR, 999077, China
| | - Yingrui Deng
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, 999077, China
| | - Kunyu Zhang
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, 999077, China; School of Biomedical Sciences and Engineering, South China University of Technology, Guangzhou, 511442, China
| | - Hon Son Ooi
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, 999077, China
| | - Boguang Yang
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong SAR, 999077, China
| | - Zhi-Yong Zhang
- Translational Research Centre of Regenerative Medicine and 3D Printing of Guangzhou Medical University, Guangdong Province Engineering Research Center for Biomedical Engineering, State Key Laboratory of Respiratory Disease, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou City, Guangdong Province, 510150, China.
| | - Bo Feng
- Center for Regenerative Medicine and Health, Hong Kong Institute of Science and Innovation, Chinese Academy of Sciences Limited, Hong Kong SAR, 999077, China; School of Biomedical Sciences, Faculty of Medicine, Institute for Tissue Engineering and Regenerative Medicine (iTERM), CUHK-GIBH Joint Research Laboratory on Stem Cells and Regenerative Medicine, The Chinese University of Hong Kong, Hong Kong SAR, 999077, China; Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China.
| | - Liming Bian
- School of Biomedical Sciences and Engineering, South China University of Technology, Guangzhou, 511442, China; National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou, 510006, China; Key Laboratory of Biomedical Materials and Engineering of the Ministry of Education, South China University of Technology, Guangzhou, 510006, China; Guangdong Provincial Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou, 510006, China.
| |
Collapse
|
2
|
Connell M, Chen H, Jiang J, Kuan CW, Fotovati A, Chu TLH, He Z, Lengyell TC, Li H, Kroll T, Li AM, Goldowitz D, Frappart L, Ploubidou A, Patel MS, Pilarski LM, Simpson EM, Lange PF, Allan DW, Maxwell CA. HMMR acts in the PLK1-dependent spindle positioning pathway and supports neural development. eLife 2017; 6:e28672. [PMID: 28994651 PMCID: PMC5681225 DOI: 10.7554/elife.28672] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 10/05/2017] [Indexed: 01/08/2023] Open
Abstract
Oriented cell division is one mechanism progenitor cells use during development and to maintain tissue homeostasis. Common to most cell types is the asymmetric establishment and regulation of cortical NuMA-dynein complexes that position the mitotic spindle. Here, we discover that HMMR acts at centrosomes in a PLK1-dependent pathway that locates active Ran and modulates the cortical localization of NuMA-dynein complexes to correct mispositioned spindles. This pathway was discovered through the creation and analysis of Hmmr-knockout mice, which suffer neonatal lethality with defective neural development and pleiotropic phenotypes in multiple tissues. HMMR over-expression in immortalized cancer cells induces phenotypes consistent with an increase in active Ran including defects in spindle orientation. These data identify an essential role for HMMR in the PLK1-dependent regulatory pathway that orients progenitor cell division and supports neural development.
Collapse
Affiliation(s)
- Marisa Connell
- Department of PaediatricsUniversity of British ColumbiaVancouverCanada
| | - Helen Chen
- Department of PaediatricsUniversity of British ColumbiaVancouverCanada
| | - Jihong Jiang
- Department of PaediatricsUniversity of British ColumbiaVancouverCanada
| | - Chia-Wei Kuan
- Department of Pathology and Laboratory MedicineUniversity of British ColumbiaVancouverCanada
| | - Abbas Fotovati
- Department of PaediatricsUniversity of British ColumbiaVancouverCanada
| | - Tony LH Chu
- Department of PaediatricsUniversity of British ColumbiaVancouverCanada
| | - Zhengcheng He
- Department of PaediatricsUniversity of British ColumbiaVancouverCanada
| | - Tess C Lengyell
- Centre for Molecular Medicine and TherapeuticsUniversity of British ColumbiaVancouverCanada
| | - Huaibiao Li
- Leibniz Institute on Aging—Fritz Lipmann InstituteBeutenbergstrasseGermany
| | - Torsten Kroll
- Leibniz Institute on Aging—Fritz Lipmann InstituteBeutenbergstrasseGermany
| | - Amanda M Li
- Department of PaediatricsUniversity of British ColumbiaVancouverCanada
| | - Daniel Goldowitz
- Centre for Molecular Medicine and TherapeuticsUniversity of British ColumbiaVancouverCanada
- Department of Medical GeneticsUniversity of British ColumbiaVancouverCanada
| | - Lucien Frappart
- Leibniz Institute on Aging—Fritz Lipmann InstituteBeutenbergstrasseGermany
| | - Aspasia Ploubidou
- Leibniz Institute on Aging—Fritz Lipmann InstituteBeutenbergstrasseGermany
| | - Millan S Patel
- Department of Medical GeneticsUniversity of British ColumbiaVancouverCanada
| | - Linda M Pilarski
- Cross Cancer Institute, Department of OncologyUniversity of AlbertaEdmontonCanada
| | - Elizabeth M Simpson
- Centre for Molecular Medicine and TherapeuticsUniversity of British ColumbiaVancouverCanada
- Department of Medical GeneticsUniversity of British ColumbiaVancouverCanada
| | - Philipp F Lange
- Department of Pathology and Laboratory MedicineUniversity of British ColumbiaVancouverCanada
- Michael Cuccione Childhood Cancer Research ProgramBC Children’s HospitalVancouverCanada
| | - Douglas W Allan
- Department of Cellular and Physiological SciencesLife Sciences Centre, University of British ColumbiaVancouverCanada
| | - Christopher A Maxwell
- Department of PaediatricsUniversity of British ColumbiaVancouverCanada
- Michael Cuccione Childhood Cancer Research ProgramBC Children’s HospitalVancouverCanada
| |
Collapse
|
3
|
Lu X, Huang W. PiggyBac mediated multiplex gene transfer in mouse embryonic stem cell. PLoS One 2014; 9:e115072. [PMID: 25517991 PMCID: PMC4269400 DOI: 10.1371/journal.pone.0115072] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 11/18/2014] [Indexed: 02/08/2023] Open
Abstract
PiggyBac system has been shown to have a high efficiency to mediate gene transfer. However, there are no reports on its efficiency to mediate multiplex transgenes in mouse embryonic stem cells. Here we first established an immortalized feeder cell line by introducing four antibiotic resistance genes simultaneously into the original SNL 76/7 feeder cell line utilizing the PiggyBac system. This is the feeder cell line with the most diverse types of antibiotic resistance genes reported so far, which will enable researchers to perform simultaneous multiplex gene transfer or gene targeting experiments in ES cells. With such feeder cell line, we were able to quantitatively characterize the transposition efficiency of PiggyBac system in mouse ES cells using five transposons carrying different inducible fluorescence proteins and antibiotic resistance genes, and the efficiency ranged from about 2% for one transposon to 0.5% for five transposons. The highly efficient multiplex gene transfer mediated by PiggyBac will no doubt provide researchers with more choices in biomedical research and development.
Collapse
Affiliation(s)
- Xibin Lu
- Department of Biochemistry, the University of Hong Kong, Hong Kong, China
| | - Wei Huang
- Department of Biochemistry, the University of Hong Kong, Hong Kong, China
- Department of Biology, Shenzhen Key Laboratory of Cell Microenvironment, South University of Science and Technology of China, Shenzhen, China
- * E-mail:
| |
Collapse
|
4
|
Chang YW, Huang YS. Arsenite-activated JNK signaling enhances CPEB4-Vinexin interaction to facilitate stress granule assembly and cell survival. PLoS One 2014; 9:e107961. [PMID: 25237887 PMCID: PMC4169592 DOI: 10.1371/journal.pone.0107961] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 08/18/2014] [Indexed: 01/15/2023] Open
Abstract
Stress granules (SGs) are compartmentalized messenger ribonucleoprotein particles (mRNPs) where translationally repressed mRNAs are stored when cells encounter environmental stress. Cytoplasmic polyadenylation element-binding protein (CPEB)4 is a sequence-specific RNA-binding protein and translational regulator. In keeping with the results obtained from the study of other RNA-binding proteins, we found CPEB4 localized in SGs in various arsenite-treated cells. In this study, we identified that Vinexin, a CPEB4-interacting protein, is a novel component of SGs. Vinexin is a SH3-domain-containing adaptor protein and affects cell migration through its association with Vinculin to localize at focal adhesions (FAs). Unexpectedly, Vinexin is translocated from FAs to SGs under arsenite-induced stress. The recruitment of Vinexin to SGs depends on its interaction with CPEB4 and influences SG formation and cell survival. Arsenite-activated c-Jun N-terminal kinase (JNK) signaling enhances the association between CPEB4 and Vinexin, which consequently facilitates SG localization of Vinexin. Taken together, this study uncovers a novel interaction between a translational regulator and an adaptor protein to influence SG assembly and cell survival.
Collapse
Affiliation(s)
- Yu-Wei Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Yi-Shuian Huang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- * E-mail:
| |
Collapse
|
5
|
Lü D, Luo C, Zhang C, Li Z, Long M. Differential regulation of morphology and stemness of mouse embryonic stem cells by substrate stiffness and topography. Biomaterials 2014; 35:3945-55. [PMID: 24529627 DOI: 10.1016/j.biomaterials.2014.01.066] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 01/27/2014] [Indexed: 12/13/2022]
Abstract
The maintenance of stem cell pluripotency or stemness is crucial to embryonic development and differentiation. The mechanical or physical microenvironment of stem cells, which includes extracellular matrix stiffness and topography, regulates cell morphology and stemness. Although a growing body of evidence has shown the importance of these factors in stem cell differentiation, the impact of these biophysical or biomechanical regulators remains insufficiently characterized. In the present study, we applied a micro-fabricated polyacrylamide hydrogel substrate with two elasticities and three topographies to systematically test the morphology, proliferation, and stemness of mESCs. The independent or combined impact of the two factors on specific cell functions was analyzed. Cells are able to grow effectively on both polystyrene and polyacrylamide substrates in the absence of feeder cells. Substrate stiffness is predominant in preserving stemness by enhancing Oct-4 and Nanog expression on a soft polyacrylamide substrate. Topography is also a critical factor for manipulating stemness via the formation of a relatively flattened colony on a groove or pillar substrate and a spheroid colony on a hexagonal substrate. Although topography is less effective on soft substrates, it plays a role in retaining cell stemness on stiff, hexagonal or pillar-shaped substrates. mESCs also form, in a timely manner, a 3D structure on groove or hexagonal substrates. These results further the understanding of stem cell morphology and stemness in a microenvironment that mimics physiological conditions.
Collapse
Affiliation(s)
- Dongyuan Lü
- Center of Biomechanics and Bioengineering and Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chunhua Luo
- Center of Biomechanics and Bioengineering and Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chen Zhang
- Center of Biomechanics and Bioengineering and Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhan Li
- Center of Biomechanics and Bioengineering and Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Mian Long
- Center of Biomechanics and Bioengineering and Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
| |
Collapse
|
6
|
Lim TT, Geisen C, Hesse M, Fleischmann BK, Zimmermann K, Pfeifer A. Lentiviral vector mediated thymidine kinase expression in pluripotent stem cells enables removal of tumorigenic cells. PLoS One 2013; 8:e70543. [PMID: 23936225 PMCID: PMC3728319 DOI: 10.1371/journal.pone.0070543] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 06/20/2013] [Indexed: 01/12/2023] Open
Abstract
Embryonic stem cells (ES) and induced pluripotent stem (iPS) cells represent promising tools for cell-based therapies and regenerative medicine. Nevertheless, implantation of ES cell derived differentiated cells holds the risk of teratoma formation due to residual undifferentiated cells. In order to tackle this problem, we used pluripotent stem cells consisting of ES and iPS cells of mouse genetically modified by lentiviral vectors (LVs) carrying herpes simplex virus thymidine kinase (HSV-TK) under the control of different promoters of pluripotency genes. Cells expressing TK in turn are eliminated upon administration of the prodrug ganciclovir (GCV). Our aim was to study the conditions required for a safe mechanism to clear residual undifferentiated cells but using low MOIs of lentiviruses to reduce the risk of insertional mutagenesis. Our in vitro data demonstrated that TK expression in pluripotent stem cells upon treatment with GCV led to elimination of undifferentiated cells. However, introduction of hygromycin resistance in the LV transduced ES cells followed by pre-selection with hygromycin and GCV treatment was required to abolish undifferentiated cells. Most importantly, transplantation of pre-selected ES cells that had been transduced with low MOI LV in mice resulted in no teratoma development after GCV treatment in vivo. Taken together, our data show that pre-selection of ES cells prior to in vivo application is necessary if vector integration events are minimized. The study presented here gives rise to safer use of pluripotent stem cells as promising cell sources in regenerative medicine in the future.
Collapse
Affiliation(s)
- Tiong-Ti Lim
- Institute of Pharmacology and Toxicology, University of Bonn, Bonn, Germany
- NRW International Graduate Research School Biotech, PHARMA, Bonn, Germany
| | - Caroline Geisen
- Institute of Physiology I, University of Bonn, Bonn, Germany
| | - Michael Hesse
- Institute of Physiology I, University of Bonn, Bonn, Germany
| | - Bernd K. Fleischmann
- NRW International Graduate Research School Biotech, PHARMA, Bonn, Germany
- Institute of Physiology I, University of Bonn, Bonn, Germany
- PharmaCenter Bonn, University of Bonn, Bonn, Germany
| | - Katrin Zimmermann
- Institute of Pharmacology and Toxicology, University of Bonn, Bonn, Germany
- NRW International Graduate Research School Biotech, PHARMA, Bonn, Germany
- * E-mail: (AP); (KZ)
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology, University of Bonn, Bonn, Germany
- NRW International Graduate Research School Biotech, PHARMA, Bonn, Germany
- PharmaCenter Bonn, University of Bonn, Bonn, Germany
- * E-mail: (AP); (KZ)
| |
Collapse
|
7
|
Wei Y, Li L, Zhou X, Zhang QY, Dunbar A, Liu F, Kluetzman K, Yang W, Ding X. Generation and characterization of a novel Cyp2a(4/5)bgs-null mouse model. Drug Metab Dispos 2012; 41:132-40. [PMID: 23073733 DOI: 10.1124/dmd.112.048736] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Knockout mouse models targeting various cytochrome P450 (P450 or CYP) genes are valuable for determining P450's biologic functions, including roles in drug metabolism and chemical toxicity. In this study, a novel Cyp2a(4/5)bgs-null mouse model was generated, in which a 1.2-megabase pair genomic fragment containing nine Cyp genes in mouse chromosome 7 (including, sequentially, Cyp2a5, 2g1, 2b19, 2b23, 2a4, 2b9, 2b13, 2b10, and 2s1) are deleted, through Cre-mediated recombination in vivo. The resultant mouse strain was viable and fertile, without any developmental deficits or morphologic abnormalities. Deletion of the constitutive genes in the cluster was confirmed by polymerase chain reaction analysis of the genes and the mRNAs in tissues known to express each gene. The loss of this gene cluster led to significant decreases in microsomal activities toward testosterone hydroxylation in various tissues examined, including olfactory mucosa (OM), lung, liver, and brain. In addition, systemic clearance of pentobarbital was decreased in Cyp2a(4/5)bgs-null mice, as indicated by >60% increases in pentobarbital-induced sleeping time, compared with wild-type (WT) mice. This novel Cyp2a(4/5)bgs-null mouse model will be valuable for in vivo studies of drug metabolism and chemical toxicities in various tissues, including the liver, lung, brain, intestine, kidney, skin, and OM, where one or more of the targeted Cyp genes are known to be expressed in WT mice. The model will also be valuable for preparation of humanized mice that express human CYP2A6, CYP2A13, CYP2B6, or CYP2S1, and as a knockout mouse model for five non-P450 genes (Vmn1r184, Nalp9c, Nalp4a, Nalp9a, and Vmn1r185) that were also deleted.
Collapse
Affiliation(s)
- Yuan Wei
- Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201-0509, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Aubrecht J, Goad MEP, Czopik AK, Lerner CP, Johnson KA, Simpson EM, Schiestl RH. A high G418-resistant neo(R) transgenic mouse and mouse embryonic fibroblast (MEF) feeder layers for cytotoxicity and gene targeting in vivo and in vitro. Drug Chem Toxicol 2011; 34:433-9. [PMID: 21740348 DOI: 10.3109/01480545.2010.544316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Aminoglycoside antibiotics have been in use since 1944 with the discovery of streptomycin. The aim of this study was to derive a new, highly resistant multicopy neo(R) transgenic mouse strain, named TgN3Ems, by random insertion of the plasmid, pPGKneobpA, and compare the level of drug resistance of wild-type and transgenic mice in vivo and corresponding primary mouse embryonic fibroblasts (MEFs) in vitro to a model neomycin analog, G418. The expression neoR in transgenic animals caused a 5-fold increase in the approximate lethal dose of G418, compared to wild type. No adverse pathological changes were found for the transgenic mice treated with G418, as they all died within minutes after injection. In contrast, the G418 treatment of wild-type mice resulted in a marked liver and kidney toxicity detected microscopically and via increases of serum biomarkers for liver and kidney damage. In addition, there was a mild bone marrow and lymphoid depletion. In in vitro studies, the transgenic MEFs survived 20-fold higher G418 levels, compared to the wild-type MEF cells. Therefore, TgN3Ems transgenic mice could be used as a source of G418-resistant feeder cells for gene targeting. Since the expression of drug-resistance genes in transgenic animals confers resistance to toxicity, the TgN3Ems mice might serve as a tool applicable in drug design.
Collapse
Affiliation(s)
- Jiri Aubrecht
- Harvard School of Public Health, Boston, Massachusetts, USA
| | | | | | | | | | | | | |
Collapse
|
9
|
Selection by drug resistance proteins located in the mitochondria of mammalian cells. Mitochondrion 2008; 8:345-51. [PMID: 18721905 DOI: 10.1016/j.mito.2008.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 06/19/2008] [Accepted: 07/18/2008] [Indexed: 12/17/2022]
Abstract
Transformation of mitochondria in mammalian cells is now a technical challenge. In this report, we demonstrate that the standard drug resistant genes encoding neomycin and hygromycin phosphotransferases can potentially be used as selectable markers for mammalian mitochondrial transformation. We re-engineered the drug resistance genes to express proteins targeted to the mitochondrial matrix and confirmed the location of the proteins in the cells by fusing them with GFP and by Western blot and mitochondrial content mixing analyses. We found that the mitochondrially targeted-drug resistance proteins confer resistance to high levels of G418 and hygromycin without affecting the viability of cells.
Collapse
|
10
|
Fan H, Zhang F, Hu J, Liu D, Zhao Z. Promoter polymorphisms of DNMT3B and the risk of colorectal cancer in Chinese: a case-control study. J Exp Clin Cancer Res 2008; 27:24. [PMID: 18662374 PMCID: PMC2515831 DOI: 10.1186/1756-9966-27-24] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 07/28/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND DNA-methyltransferase-3B (DNMT3B), which plays a role in DNA methylation, is usually aberrant expression involved in carcinogenesis. Polymorphisms of the DNMT3B gene may influence DNMT3B activity on DNA methylation in several cancers, thereby modulating the susceptibility to cancer. METHODS DNMT3B -579G>T genotypes and -149C>T were determined by PCR-RFLP and sequencing in 137 colorectal cancer patients and 308 controls matched for age and sex, who did not receive radiotherapy or chemotherapy for newly diagnosed and histopathologically confirmed colorectal cancer. The association between two SNPs of the DNMT3B promoter and the risk of the development of colorectal cancer was analyzed in a population of Chinese. RESULTS The allele frequency of -149C >T among patients and controls was 0.73% versus 0.65%, respectively. The allele frequency of -597G>T for patients and controls was 6.57% versus 11.53%, respectively. Individuals with at least one -149C>T allele were no at a significantly increase risk of colorectal cancer compared with those having a -149TT genotype. However, Individuals with at least one 579G>T allele were decreased risk of colorectal cancer compared with those having a -579TT genotype. CONCLUSION The relative distribution of -149C>T DNMT3B SNPs among a Chinese population can not be used as a stratification marker to predict an individual's susceptibility to colorectal cancer. However, the DNMT3B -579G>T polymorphism may contribute to the genetic susceptibility to colorectal cancer.
Collapse
Affiliation(s)
- Hong Fan
- Key Laboratory of Developmental genes and Human diseases, Ministry of Education, Southeast University, 210009, Nanjing, PR China
- Department of Genetics & Developmental Biology, The School of Basic Medical Sciences, Southeast University, 210009, Nanjing, PR China
| | - Feng Zhang
- Key Laboratory of Developmental genes and Human diseases, Ministry of Education, Southeast University, 210009, Nanjing, PR China
| | - Jiabo Hu
- School of Medicine, Jiangsu University, 212001, Zhenjiang, PR China
| | - Dongsheng Liu
- Key Laboratory of Developmental genes and Human diseases, Ministry of Education, Southeast University, 210009, Nanjing, PR China
| | - Zhujiang Zhao
- Key Laboratory of Developmental genes and Human diseases, Ministry of Education, Southeast University, 210009, Nanjing, PR China
- Department of Genetics & Developmental Biology, The School of Basic Medical Sciences, Southeast University, 210009, Nanjing, PR China
| |
Collapse
|
11
|
Fan H, Liu DS, Zhang SH, Hu JB, Zhang F, Zhao ZJ. DNMT3B 579 G>T promoter polymorphism and risk of esophagus carcinoma in Chinese. World J Gastroenterol 2008; 14:2230-4. [PMID: 18407600 PMCID: PMC2703851 DOI: 10.3748/wjg.14.2230] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 02/04/2008] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the relationship between 579 G>T polymorphisms in the DNMT3B gene, which is involved in de novo methylation and associated with the risk of esophagus cancer (EC) in Chinese. METHODS DNMT3B 579 G>T genotypes were determined by PCR-RFLP in 194 EC patients and 210 healthy controls matched for age and sex, who did not receive radiotherapy or chemotherapy for newly diagnosed and histopathologically confirmed EC. RESULTS In control subjects, the frequency of T/T and G/T genotypes, and T and G alleles was 81.4%, 18.1%, 90.05% and 9.55%, respectively. The distribution of genotypes and allelotypes in the EC patients was not significantly different from that in the controls. When stratified by sex and age, there was still no significant association between the risks of EC and GT and GG genotypes. This study also showed a distinct difference in the distribution of DNMT3B and single nucleotide polymorphism (SNP) between Chinese and Koreans. CONCLUSION DNMT3B 579 G>T polymorphism may not be a stratification marker to predict the susceptibility to EC, at least in Chinese. DNMT3B promoter SNP is diverse in ethnic populations.
Collapse
|
12
|
Forster A, Pannell R, Drynan LF, McCormack M, Collins EC, Daser A, Rabbitts TH. Engineering de novo reciprocal chromosomal translocations associated with Mll to replicate primary events of human cancer. Cancer Cell 2003; 3:449-58. [PMID: 12781363 DOI: 10.1016/s1535-6108(03)00106-5] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The etiology of human tumors often involves chromosomal translocations. Models that emulate translocations are essential to understanding the determinants of frank malignancy, those dictating the restriction of translocations to specific lineages, and as a basis for development of rational therapeutic methods. We demonstrate that developmentally regulated Cre-loxP-mediated interchromosomal recombination between the Mll gene, whose human counterpart is involved in a spectrum of leukemias, and the Enl gene creates reciprocal chromosomal translocations that cause myeloid tumors. There is a rapid onset and high penetrance of leukemogenesis in these translocator mice, and high proportions of cells carrying chromosomal translocations can be found in bone marrow as early as 12 days after birth. This de novo strategy is a direct recapitulation of naturally occurring human cancer-associated translocations.
Collapse
Affiliation(s)
- Alan Forster
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
13
|
Lauth M, Spreafico F, Dethleffsen K, Meyer M. Stable and efficient cassette exchange under non-selectable conditions by combined use of two site-specific recombinases. Nucleic Acids Res 2002; 30:e115. [PMID: 12409474 PMCID: PMC135837 DOI: 10.1093/nar/gnf114] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Work of the last decade has proven the 'one gene- one product-one function' hypothesis an oversimplification. To further unravel the emerging 'one gene-multiple products-even more functions' concept, new methods (such as subtle knock-in and tightly regulated conditional mutations) for the analysis of gene function in health and disease are required. Another class of improvements (such as tetraploid fusion and cassette exchange) addresses the efficiency with which targeted mutant strains can be generated. Recombinase-mediated cassette exchange (RMCE), which in theory is well suited for the rapid generation of multiple alleles of a given locus, is hampered by its low efficiency in the absence of selection and, especially in vivo, by the promiscuity of the participating recombinase recognition sites. Here we present a novel approach which circumvents this problem by the use of two independent recombinase systems. The strategy, which uses loxP on one and FRT on the other side of the cassette together with a Cre/Flpe expression vector, prevents excisive events and results in higher rates of cassette integration without selection than previously described. This method has a huge potential for the generation of allelic series in embryonic stem cells and, importantly, in pre-implantation embryos in vivo.
Collapse
Affiliation(s)
- Matthias Lauth
- Division of Molecular Genetics, Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK.
| | | | | | | |
Collapse
|
14
|
Chan MF, van Amerongen R, Nijjar T, Cuppen E, Jones PA, Laird PW. Reduced rates of gene loss, gene silencing, and gene mutation in Dnmt1-deficient embryonic stem cells. Mol Cell Biol 2001; 21:7587-600. [PMID: 11604495 PMCID: PMC99930 DOI: 10.1128/mcb.21.22.7587-7600.2001] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Tumor suppressor gene inactivation is a crucial event in oncogenesis. Gene inactivation mechanisms include events resulting in loss of heterozygosity (LOH), gene mutation, and transcriptional silencing. The contribution of each of these different pathways varies among tumor suppressor genes and by cancer type. The factors that influence the relative utilization of gene inactivation pathways are poorly understood. In this study, we describe a detailed quantitative analysis of the three major gene inactivation mechanisms for a model gene at two different genomic integration sites in mouse embryonic stem (ES) cells. In addition, we targeted the major DNA methyltransferase gene, Dnmt1, to investigate the relative contribution of DNA methylation to these various competing gene inactivation pathways. Our data show that gene loss is the predominant mode of inactivation of a herpes simplex virus thymidine kinase neomycin phosphotransferase reporter gene (HSV-TKNeo) at the two integration sites tested and that this event is significantly reduced in Dnmt1-deficient cells. Gene silencing by promoter methylation requires Dnmt1, suggesting that the expression of Dnmt3a and Dnmt3b alone in ES cells is insufficient to achieve effective gene silencing. We used a novel assay to show that missense mutation rates are also substantially reduced in Dnmt1-deficient cells. This is the first direct demonstration that DNA methylation affects point mutation rates in mammalian cells. Surprisingly, the fraction of CpG transition mutations was not reduced in Dnmt1-deficient cells. Finally, we show that methyl group-deficient growth conditions do not cause an increase in missense mutation rates in Dnmt1-proficient cells, as predicted by methyltransferase-mediated mutagenesis models. We conclude that Dnmt1 deficiency and the accompanying genomic DNA hypomethylation result in a reduction of three major pathways of gene inactivation in our model system.
Collapse
Affiliation(s)
- M F Chan
- Department of Biochemistry and Molecular Biology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, 90089-9176, USA
| | | | | | | | | | | |
Collapse
|
15
|
Gillessen S, Mach N, Small C, Mihm M, Dranoff G. Overlapping roles for granulocyte-macrophage colony-stimulating factor and interleukin-3 in eosinophil homeostasis and contact hypersensitivity. Blood 2001; 97:922-8. [PMID: 11159518 DOI: 10.1182/blood.v97.4.922] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Studies of mice rendered deficient in granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-3 (IL-3) have established unique roles for these cytokines in pulmonary homeostasis, resistance to infection, and antigen-specific T- and B-cell responses. In addition to these distinctive properties, however, GM-CSF and IL-3 also stimulate the development and activation of hematopoietic cells in many similar ways, raising the possibility that each factor might partially compensate for the other's absence in singly deficient mice. To test whether endogenous GM-CSF and IL-3 mediate redundant functions in vivo, we generated mice lacking both cytokines through sequential gene targeting experiments in embryonic stem (ES) cells. Surprisingly, doubly deficient animals, but not single knockouts, showed increased numbers of circulating eosinophils. Doubly deficient mice, moreover, developed weaker contact hypersensitivity reactions to haptens applied epicutaneously than mice deficient in either factor alone. Together, these findings delineate overlapping roles for GM-CSF and IL-3 in hematopoiesis and immunity. (Blood. 2001;97:922-928)
Collapse
Affiliation(s)
- S Gillessen
- Department of Adult Oncology, Dana-Farber Cancer Institute Harvard Medical School, Boston, MA, USA
| | | | | | | | | |
Collapse
|
16
|
Collins EC, Pannell R, Simpson EM, Forster A, Rabbitts TH. Inter-chromosomal recombination of Mll and Af9 genes mediated by cre-loxP in mouse development. EMBO Rep 2000; 1:127-32. [PMID: 11265751 PMCID: PMC1084253 DOI: 10.1093/embo-reports/kvd021] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2000] [Revised: 05/04/2000] [Accepted: 05/22/2000] [Indexed: 11/13/2022] Open
Abstract
Chromosomal translocations are crucial events in the aetiology of many leukaemias, lymphomas and sarcomas, resulting in enforced oncogene expression or the creation of novel fusion genes. The study of the biological outcome of such events ideally requires recapitulation of the tissue specificity and timing of the chromosomal translocation itself. We have used the Cre-loxP system of phage P1 to induce de novo Mll-Af9 chromosomal recombination during mouse development. loxP sites were introduced into the Mll and Af9 genes on chromosomes 9 and 4, respectively, and mice carrying these alleles were crossed with mice expressing Cre recombinase. A resulting Mll-Af9 fusion gene was detected whose transcription and splicing were verified. Thus, programmed interchromosomal recombination can be achieved in mice. This approach should allow the design of mouse models of tumorigenesis with greater biological relevance than those available at present.
Collapse
Affiliation(s)
- E C Collins
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | | | | | | |
Collapse
|
17
|
Soukharev S, Miller JL, Sauer B. Segmental genomic replacement in embryonic stem cells by double lox targeting. Nucleic Acids Res 1999. [DOI: 10.1093/nar/27.18.e21-i] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
|
18
|
Webber AL, Ingram RS, Levorse JM, Tilghman SM. Location of enhancers is essential for the imprinting of H19 and Igf2 genes. Nature 1998; 391:711-5. [PMID: 9490417 DOI: 10.1038/35655] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Genomic imprinting is the process in mammals by which gamete-specific epigenetic modifications establish the differential expression of the two alleles of a gene. The tightly linked H19 and Igf2 genes are expressed in tissues of endodermal and mesodermal origin, with H19 expressed from the maternal chromosome and Igf2 expressed from the paternal chromosome. A model has been proposed to explain the reciprocal imprinting of these genes; in this model, expression of the genes is governed by competition between their promoters for a common set of enhancers. An extra set of enhancers might be predicted to relieve the competition, thereby eliminating imprinting. Here we tested this prediction by generating mice with a duplication of the endoderm-specific enhancers. The normally silent Igf2 gene on the maternal chromosome was expressed in liver, consistent with relief from competition. We then generated a maternal chromosome containing a single set of enhancers located equidistant from 1gf2 and H19; the direction of the imprint was reversed. Thus, the location of the enhancers determines the outcome of competition in liver, and the strength of the H19 promoter is not sufficient to silence Igf2.
Collapse
Affiliation(s)
- A L Webber
- Howard Hughes Medical Institute and Department of Molecular Biology, Princeton University, New Jersey 08544, USA
| | | | | | | |
Collapse
|
19
|
Tucker KL, Wang Y, Dausman J, Jaenisch R. A transgenic mouse strain expressing four drug-selectable marker genes. Nucleic Acids Res 1997; 25:3745-6. [PMID: 9278500 PMCID: PMC146932 DOI: 10.1093/nar/25.18.3745] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Murine embryonic stem (ES) cells are commonly cultured on feeder layers of primary murine embryonic fibroblasts (MEFs). Because gene targeting experiments often involve sequential selection for multiple-drug resistance in single ES cell lines, we have developed a new mouse strain which represents an economical donor for the production of multiple-drug resistant MEFs. MEFs prepared from the DR-4 mouse strain displayed resistance to concentrations of the drugs G418, 6-thioguanine, puromycin and hygromycin well above those used normally for the selection of drug-resistant ES cells.
Collapse
Affiliation(s)
- K L Tucker
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | | | | | | |
Collapse
|
20
|
Borriello F, Sethna MP, Boyd SD, Schweitzer AN, Tivol EA, Jacoby D, Strom TB, Simpson EM, Freeman GJ, Sharpe AH. B7-1 and B7-2 have overlapping, critical roles in immunoglobulin class switching and germinal center formation. Immunity 1997; 6:303-13. [PMID: 9075931 DOI: 10.1016/s1074-7613(00)80333-7] [Citation(s) in RCA: 391] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Humoral immune responses were characterized in mouse strains lacking either or both B7 molecules. Mice deficient in both B7-1 and B7-2 failed to generate antigen-specific IgG1 and IgG2a responses and lacked germinal centers when immunized by a number of routes and even in the presence of complete Freund's adjuvant. These results demonstrate that B7-mediated signaling plays a critical role in germinal center formation and immunoglobulin class switching in vivo. Mice lacking only B7-1 or B7-2 mounted high-titer antigen-specific IgG responses when immunized in complete Freund's adjuvant, indicating that B7-1 and B7-2 can have overlapping, compensatory functions for IgG responses. When immunized intravenously without adjuvant, B7-2-deficient mice failed to switch antibody isotypes or form germinal centers, whereas B7-1-deficient mice gave antibody responses comparable with wild-type mice. Thus, B7-2 has an important role in initiating antibody responses in the absence of adjuvant, but the induction of B7-1 by adjuvant in B7-2-deficient mice can compensate for the absence of B7-2.
Collapse
Affiliation(s)
- F Borriello
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|