Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mammals defend against viruses differently than invertebrates

24.06.2014

Biologists have long wondered if mammals share the elegant system used by insects, bacteria and other invertebrates to defend against viral infection. Two back-to-back studies in the journal Science last year said the answer is yes, but a study just published in Cell Reports by researchers at the Icahn School of Medicine at Mount Sinai found the opposite.

In the Mount Sinai study, the results found that the defense system used by invertebrates — RNA interferences or RNAi — is not used by mammals as some had argued. RNAi are small molecules that attach to molecular scissors used by invertebrates to cut up invading viruses.

Mammals use a form of RNAi to fine-tune the expression of hundreds of genes that coordinate development in the womb, says the study's senior author, Benjamin tenOever, PhD, Fishberg Professor in the Department of Medicine and Department of Microbiology at the Icahn School of Medicine at Mount Sinai. But it has never been clear that adult mammals use RNAi the same way that plants and insects do, he says. "Mammals have cell machinery that looks capable of producing RNAi to fight virus, but we believe it only helps to produce different small RNA products called microRNAs, which are not antiviral," Dr. tenOever says.

The correct answer matters because RNAi is being studied as a potential basis for new kinds of drugs for the treatment of hemophilia, beta-thalassemia and many viral infections, says Dr. tenOever.

"We believe our results settle a longstanding debate about whether mammals, including humans and mice, fight viruses using RNAi, and the answer is good news," he says. "Drug designers interested in using RNAi to treat disease have worried that if RNAi is part of the mammalian response to viral infections, RNAi-based agents could compromise a human's immune response, producing unintended consequences. That is not a concern now, based on our findings."

Mammals are known to fend off viruses with a system based on interferons, signaling proteins made by immune cells that amplify the body's attack on invaders. The finding that mammals do not use RNAi to fight viruses suggests that RNAi-based drugs could augment the existing interferon response in mammals, Dr. tenOever says. "We could harness this potent RNAi viral-killing machine when natural human immunity isn't enough."

To answer the question, a team of researchers from the Icahn Graduate School of Biomedical Science used a virus that produces oral lesions in cows and pigs. They eliminated the part of the virus that causes disease, rendering it harmless and susceptible to both RNAi and interferons. They then took this harmless virus and gave it the capacity to block either interferon or RNAi.

In experiments with mice, when the virus was designed to block interferon, no immune defense occurred and the interferon-blocking virus flourished. In contrast, giving the virus the capacity to block RNAi, found that the animals mounted a robust interferon-based defense that further weakened the RNAi-blocking virus. The same thing happened when the RNAi-blocking virus was introduced to engineered mice that could not produce interferons. "If mammals used interferon and RNAi to fight the virus, we would have seen the RNAi-blocking virus flourish in at least this setting — but we did not," Dr. tenOever says. "This is the strongest published data that argues against recent claims that RNAi exists in mammals, he says.

###

Study co-authors include Mount Sinai researchers Simone Backes, PhD, Ryan Langlois, PhD, Sonja Schmid, PhD, Andrew Varble, PhD, Jaehee Shim and David Sachs. The study was supported in part by the U.S. Army Research Laboratory and the U.S. Army Research Office under grant numbers W911NF-12-R-0012 and W911NF-07-R-0003.

About the Mount Sinai Health System

The Mount Sinai Health System is an integrated health system committed to providing distinguished care, conducting transformative research, and advancing biomedical education. Structured around seven member hospital campuses and a single medical school, the Health System has an extensive ambulatory network and a range of inpatient and outpatient services—from community‐based facilities to tertiary and quaternary care.

The System includes approximately 6,600 primary and specialty care physicians, 12‐minority‐owned free‐standing ambulatory surgery centers, over 45 ambulatory practices throughout the five boroughs of New York City, Westchester, and Long Island, as well as 31 affiliated community health centers. Physicians are affiliated with the Icahn School of Medicine at Mount Sinai, which is ranked among the top 20 medical schools both in National Institutes of Health funding and by U.S. News & World Report.

For more information, visit http://www.mountsinai.org, or find Mount Sinai on Facebook, Twitter and YouTube.

Greg Williams | Eurek Alert!

Further reports about: Health Medicine RNA RNAi immune infections interferons producing viruses

More articles from Life Sciences:

nachricht Life on the edge prepares plants for climate change
18.12.2017 | Max-Planck-Institut für Entwicklungsbiologie

nachricht Lipid nanodiscs stabilize misfolding protein intermediates red-handed
18.12.2017 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Error-free into the Quantum Computer Age

A study carried out by an international team of researchers and published in the journal Physical Review X shows that ion-trap technologies available today are suitable for building large-scale quantum computers. The scientists introduce trapped-ion quantum error correction protocols that detect and correct processing errors.

In order to reach their full potential, today’s quantum computer prototypes have to meet specific criteria: First, they have to be made bigger, which means...

Im Focus: Search for planets with Carmenes successful

German and Spanish researchers plan, build and use modern spectrograph

Since 2016, German and Spanish researchers, among them scientists from the University of Göttingen, have been hunting for exoplanets with the “Carmenes”...

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Single-photon detector can count to 4

18.12.2017 | Information Technology

Quantum memory with record-breaking capacity based on laser-cooled atoms

18.12.2017 | Physics and Astronomy

How much soil goes down the drain -- New data on soil lost due to water

18.12.2017 | Agricultural and Forestry Science

VideoLinks
B2B-VideoLinks
More VideoLinks >>>