Researchers from the Massachusetts General Hospital Center for Regenerative Medicine (MGH-CRM) and the Harvard Stem Cell Institute have a developed a new type of human pluripotent stem cell that can be manipulated more readily than currently available stem cells. As described in the June 4 Cell Stem Cell, these new cells could be used to create better cellular models of disease processes and eventually may permit repair of disease-associated gene mutations.
"It has been fairly easy to manipulate stem cells from mice, but this has not been the case for traditional human stem cells," explains Niels Geijsen, PhD, of the MGH-CRM, who led the study. "We had previously found that the growth factors in which mouse stem cells are derived define what those cells can do, and now we've applied those findings to human stem cells."
The first mammalian embryonic stem cells (ESCs) were derived from mice and have proven very useful for studying gene function and the impact of changes to individual genes. But techniques used in these studies to introduce a different version of a single gene or inactivate a particular gene were ineffective in human ESCs. In addition, human ESCs proliferate much more slowly than do cells derived from mice and grow in flat, two-dimensional colonies, while mouse ESCs form tight, three-dimensional colonies. It is been extremely difficult to propagate human ESCs from a single cell, which prevents the creation of genetically manipulated human embryonic stem cell lines.
In previous work, Geijsen and his colleagues demonstrated that the growth factor conditions under which stem cells are maintained in culture play an important role in defining the cells' functional properties. Since the growth factors appeared to make such a difference, the researchers tried to make a more useful human pluripotent cell using a new approach. They derived human induced pluripotent stem cells (iPSCs) – which are created by reprogramming adult cells and have many of the characteristics of human ECSs, including resistance to manipulation – in cultures containing the growth factor LIF, which is used in the creation of mouse ESCs.
The resulting cells visibly resembled mouse ESCs and proved amenable to a standard gene manipulation technique that exchanges matching sequences of DNA, allowing the targeted deactivation or correction of a specific gene. The ability to manipulate these new cells depended on both the continued presence of LIF and expression of the five genes that are used in reprogramming adult cells into iPSCs. If any of those factors was removed, these hLR5- (for human LIF and five reprogramming factors) iPSCs reverted to standard iPSCs.
"Genetic changes introduced into hLR5-iPSCs would be retained when they are coverted back to iPSCs, which we then can use to generate cell lines for future research, drug development and someday stem-cell based gene-correction therapies," says Geijsen. He is an assistant professor of Medicine at Harvard Medical School and a principal faculty member of the Harvard Stem Cell Institute.
Co-authors of the Cell Stem Cell paper are lead author Christa Buecker, MGH-CRM and Harvard Stem Cell Institute (HSCI); Hsu-Hsin Chen, PhD, Laurence Dahern, and Konrad Hochedlinger, PhD, MGH-CRM and HSCI; Patricia Okwieka, MGH-CRM; Jose Polo, PhD, MGH Cancer Center; Lei Bu, PhD, MGH Cardiovascular Research Center; Tahsin Stefan Barakat and Joost Gribnau, PhD, University Medical Center, Rotterdam, The Netherlands; and Andrew Porter, PhD, Imperial College London, U.K. The study was supported by grants from the National Institutes of Health, the Dutch Science Organization, the Gottlieb Daimler and Karl Benz Foundation and the National Science Council of Taiwan.
Massachusetts General Hospital, established in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget of more than $600 million and major research centers in AIDS, cardiovascular research, cancer, computational and integrative biology, cutaneous biology, human genetics, medical imaging, neurodegenerative disorders, regenerative medicine, systems biology, transplantation biology and photomedicine.
Sue McGreevey | EurekAlert!
Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover
First transcription atlas of all wheat genes expands prospects for research and cultivation
17.08.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences