Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Interfering RNA silences genes in ’slippery’ immune cells

09.05.2006
Novel lab technique expands researchers’ toolbox

A technical advance in laboratory techniques may provide biology researchers broader access to RNA interference, a process of blocking the activity of targeted genes. RNA interference has recently emerged as an important tool in studying how genes function in normal biological processes and in disease.

Writing in the Journal of Immunological Methods, published online on March 24, a research team from The Children’s Hospital of Philadelphia combined laboratory technologies in using RNA interference to manipulate human T cells. T cells are immune cells that circulate in the blood, with important roles in autoimmune diseases, infectious diseases and some cancers.

"T cells have previously been difficult to modify with interfering RNA, being more mobile than other cell types that typically remain stationary in cell cultures," said study leader Terri H. Finkel, M.D., Ph.D., chief of Rheumatology at The Children’s Hospital of Philadelphia. "Our approach achieves results comparable to the conventional technique, which uses synthetic small interfering RNA but is very expensive and in short supply. We expect our technique to expand the toolbox for scientists doing research in immunology."

RNA interference (RNAi), which naturally occurs in cells, is a process in which brief RNA sequences, called small interfering RNA (siRNA) block signals from a particular gene. This process, called gene silencing, inhibits the gene from carrying out its function of creating a protein or another gene product. The body often uses RNAi as a defense against the action of hostile viruses.

Over the past few years, biomedical researchers have been investigating how they might eventually harness RNAi in new medicines. Another line of research uses RNAi as a research tool, investigating the functions of specific genes by studying what happens when RNAi temporarily silences them--a process calling "knocking down" the gene.

The research by Dr. Finkel’s team aims to extend RNAi to a wider pool of researchers by making the technique less expensive and more widely available, as well as adapting it to T cells, a cell type previously intractable to such manipulation. Their technique combines three technologies already accessible to lab investigators: nucleofection, siRNA expression cassettes, and siRNA expression vectors. Nucleofection technology uses specialized solutions and electrical pulses to temporarily open a cell nucleus. Into the nucleus, researchers insert a payload of DNA.

The DNA holds a sequence of genetic code that produces a specific siRNA after it enters a nucleus. The researchers encased the DNA within an siRNA expression cassette (SEC), an inexpensive, quickly synthesized product that carries genetic sequences to regulate the gene activity that yields an siRNA. After the researchers tested a variety of SECs to determine which is the most effective, they inserted the desired SEC into a vector, a biological agent that inserts itself into a target cell’s nucleus more efficiently than an unaccompanied cassette.

The researchers first tested their approach by introducing a gene for green fluorescent protein into human T cells, and using siRNA to inhibit that gene’s expression, and dim its fluorescent glow.

They then applied their approach to HALP, a gene naturally active in T cells. Dr. Finkel previously discovered and named HALP, an acronym for "HIV-associated life preserver," showing that it had a role in prolonging HIV infection by helping HIV-infected T cells survive attack by the immune system.

Using siRNA and their laboratory techniques, the investigators succeeded in "knocking down," that is, decreasing gene expression by HALP. Because their previous research strongly suggests that HALP promotes latent HIV infection, the new technique has a potential application to HIV treatment. "The siRNA may represent a suicide vector: by knocking down HALP it may allow HIV-infected cells to self-destruct, thus eliminating a hiding place for the virus," said Dr. Finkel.

"More broadly," she added, "the technique could theoretically be directed against other immune-related diseases, by silencing harmful genes active in T cells."

Dr. Finkel’s co-authors, all from The Children’s Hospital of Philadelphia, were Jiyi Yin, Ph.D., Zhengyu Ma, Nithianandan Selliah, Ph.D., Debra K. Shivers and Randy Q. Cron, M.D., Ph.D. National Institutes of Health grants supported the research, along with support from the University of Pennsylvania Center for AIDS Research and the University’s Cancer Center, the Bender Foundation, the Joseph Lee Hollander Chair at The Children’s Hospital of Philadelphia, and the W. W. Smith Charitable Trust.

"Effective Gene Suppression Using Small Interfering RNA in Hard-to-Transfect Human T Cells." Journal of Immunological Methods. In press, published online March 24, 2006.

John Ascenzi | EurekAlert!
Further information:
http://www.chop.edu

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>