Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chromatin opening elements allow tetracycline inducible gene expression in stem cells

29.11.2018

In modern biomedicine, cell therapeutics are produced from reprogrammed stem cells (induced pluripotent stem cells, iPS). For this purpose, these cells can also undergo an additional genetic modification. However, unintentional mechanisms frequently occur, which can deactivate gene expression. Researchers from the Paul-Ehrlich-Institut (PEI) have developed inducible vectors containing ubiquitous chromatin opening elements (UCOE) which keep the relevant gene modified locus permanently open so that it remains active. The journal Biomaterials reports on these results in its online version of 24 November 2018.

Ever since the discovery of the reprogramming of normal (somatic) body cells in so-called induced pluripotent stem cells (iPS cells), the development of cell therapeutics from such pluripotent stem cells has gathered momentum.


Induced transgene expression (GFP, green fluorescence) in first stages of differentiation from iPS cells. Comparison between transmitted light and fluorescence microscopy.

Source.: PEI

While somatic cells represent specialized cells and are predetermined for one particular cell type, pluripotent stem cells can differentiate into quite a variety of different cell types. This very property is used for the development of cell therapeutics.

Not only the conversion of a normal body cell into the induced pluripotent stem cells is of scientific interest, but the road from these "formable" cells into the desired cell type (effector cell), too, represents a challenge in research.

This can be supported, among other things, by transcription factors inserted by genetic modification of the pluripotent cells. Only the activity in defined time windows will generate a benefit. Insertion of the foreign genetic information into the cells is frequently carried out using retroviral vectors.

Defective cells can thus be corrected, or the efficiency of somatic cell production from iPSC can be enhanced.

During this process, however, integrated retroviral vector genomes are often “silenced” by epigenetic mechanisms. This involves methyl groups, which are attached to certain gene sections (transgenic expression cassettes).

These methyl groups have a kind of sealing effect. The advantage of these newly inserted genes is then lost, and even the differentiation of the cells can be stopped.

How can silencing be prevented without affecting inducibility? Professor Ute Modlich's research group "Gene Modification in Stem Cells", Division Veterinary Medicine of the PEI and colleagues of Division Medical Biotechnology developed inducible vectors which keep the gene modified site open by means of ubiquitous chromatin opening elements.

For this purpose, they inserted various fragments of the human HNRPA2B1-CBX3 UCOE into inducible retroviral vectors. The vectors can be induced using a promoter which is in turn activated by the antibiotic tetracycline. This one vector contains all that is necessary. Thanks to this property, it is also referred to as "all-in-one vector".

In a next step, the researchers tested the functionality of the vectors in various cell lines and in iPSCs of mice and men. They were able to prove that inserting the UCOE would not impair the regulation of the vectors. Switching them on – which is important for good therapeutic efficacy – and off was possible without any problems.

This, in turn, is important to avoid effects of interference. Some of the tested vectors preserved their activity in iPSC of mice and humans, both in the pluripotency, and in the differentiation stage.

From the researchers’ point of view, these new vectors allow genetic modification of iPS cells with safe regulation of transgene expression. In a next step, the researchers swill use the vectors to efficiently produce blood cells from iPS cells.

Originalpublikation:

Cullmann K, Blokland KEC, Sebe S, Schenk F, Ivics Z, Heinz N, Modlich U (2018): Sustained and regulated gene expression by Tet-inducible "All-In-One" retroviral vectors containing the HNRPA2B1-CBX3 UCOE.
Biomaterials Nov 24 [Epub ahead of print].
DOI: doi.org/10.1016/j.biomaterials.2018.11.006

Weitere Informationen:

https://www.sciencedirect.com/science/article/pii/S014296121830783X?via%3Dihub - Abstract
https://www.pei.de/EN/information/journalists-press/press-releases/2018/25-chrom... - this press release on the PEI Website

Dr. Susanne Stöcker | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht Why developing nerve cells can take a wrong turn
04.06.2020 | Universität zu Köln

nachricht Innocent and highly oxidizing
04.06.2020 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Small Protein, Big Impact

In meningococci, the RNA-binding protein ProQ plays a major role. Together with RNA molecules, it regulates processes that are important for pathogenic properties of the bacteria.

Meningococci are bacteria that can cause life-threatening meningitis and sepsis. These pathogens use a small protein with a large impact: The RNA-binding...

Im Focus: K-State study reveals asymmetry in spin directions of galaxies

Research also suggests the early universe could have been spinning

An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links...

Im Focus: New measurement exacerbates old problem

Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem.

Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain...

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

Why developing nerve cells can take a wrong turn

04.06.2020 | Life Sciences

The broken mirror: Can parity violation in molecules finally be measured?

04.06.2020 | Physics and Astronomy

Innocent and highly oxidizing

04.06.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>