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 Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

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

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>