Researchers at the Paul-Ehrlich-Institut have now found the mechanism of how interferon protects the liver. In this context, specific suppressor cells and the balance between the inflammation mediator interleukin-1beta and its inhibitor, the interleukin-1 receptor antagonist play a central role. The findings may provide approaches to a more specific therapy with fewer adverse effects.
Liver histology of mice after treatment with poly(I:C). Control mice (WT) are protected by an interferon-mediated effect, mice without the interferon receptor (IFNAR-/-) develop severe liver damage.
Hepatology reports on the research results in its online prepublication (DOI:10.1002/hep.26915).
Type I interferons are mainly associated with their immunostimulatory, antiviral, and antitumoral effects. However, they also have anti-inflammatory properties. Thus, in patients with a liver inflammation due to a chronic hepatitis-C virus infection, interferon may improve the condition of the liver. This can also be observed when, thanks to treatment, the viral burden is negligible already.
PD (associate professor) Dr Zoe Waibler, head of a temporary research group at the Paul-Ehrlich-Institut (PEI), and co-workers have studied the mechanism which results in this protective effect. For the study not a virus but poly(I:C), an artificial double-stranded RNA which mimics a viral infection, was used. Poly(I:C) was applied to interferon receptor-deficient (IFNAR-deficient) mice and genetically unmodified control mice.
In IFNAR-deficient mice, the treatment with poly(I:C) induced a severe acute liver damage with necrosis, while the control animals were protected. Similarly to human liver inflammations, serum levels of the enzyme alanine aminotransferase also increased upon poly(I:C) treatment of IFNAR-deficient mice, while those of the control mice did not.
In collaboration with Professor Christian Bogdan, Institute of Clinical Microbiology, Immunology, and Hygiene of the University Hospital of Erlangen, the team of PEI researchers identified certain suppressor cells ("myeloid derived suppressor cells", MDSC) as mediators of protection: Upon type I interferon expression, these cells infiltrate the liver, where they convey the protective effect. The team achieved this by switching off the interferon receptor on individual cell types and studying specific surface markers.
Dr Waibler and co-workers were able to show that these suppressor cells influence the balance between the pro- inflammatory cytokine interleukin-1beta (IL-1beta) and its naturally occurring inhibitor, anti-inflammatory interleukin-1 receptor antagonist (IL-1RA) in the liver: For IFNAR-deficient mice, there was a drastic shift toward inflammatory IL-1beta upon poly(I:C) treatment, while for the control mice, the shift occurred in the direction of the anti-inflammatory IL-1RA.
The fact that IL-1beta and IL-1RA indeed induced the inflammatory or protective effects, respectively, in the liver could be proved by Dr Waibler and co-workers by administrating IL-1RA to IFNAR-deficient mice, which prevented the liver damage induced by poly(I:C). Although interferon could not mediate the protective effect here, due to the missing interferon receptor, the downstream effects, normally mediated by interferon, was restored by the administration of IL-1RA. Likewise, liver functions improved in IFNAR-deficient mice if the inflammatory cytokine IL-1beta was neutralized by adding an anti-IL-1beta antibody.
"Interferons have extremely versatile effects by regulating up to 300 genes, thus bringing about a great variety of effects. Only a minor part of them is responsible for this effect on the liver. Maybe an organ-specific therapy would be possible here", explained Dr Waibler with regard to a potential clinical use of these results. Biotechnologically engineered IL-1RA is used in the treatment of rheumatoid arthritis. In addition, there is a genetically engineered monoclonal antibody directed against IL-1beta, which is used in patients with a particular genetic defect.
The PEI researchers also have an explanation for the fact that the suppressor cells in the control mice infiltrate the liver: Based on experimental results, they assume that interferons switch on a particular chemokine in the liver, which attracts the suppressor cells (MDSC).
"Many immunological processes are not fully understood, yet. With our fundamental research, we contribute to developing approaches to therapies that are effective but at the same time cause as few adverse effects as possible", emphasised Professor Cichutek, president of the Paul-Ehrlich-Institut.
DOI:10.1002/hep.26915; unedited version
Conrad E, Resch TK, Gogesch P, Kalinke U, Bechmann I, Bogdan C, Waibler Z (2013): Protection against RNA-induced liver damage by myeloid cells requires type I IFN and IL-1 receptor antagonist. Hepatology [Epub ahead of print].
The Paul-Ehrlich-Institut, Federal Institute for Vaccines and Biomedicines, in Langen near Frankfurt/Main is a senior federal authority reporting to the Federal Ministry of Health (Bundesministerium für Gesundheit, BMG). It is responsible for the research, assessment, and marketing authorisation of biomedicines for human use and veterinary vaccines. Its remit also includes the authorisation of clinical trials and pharmacovigilance, i.e. recording and evaluation of potential adverse effects.
Other duties of the institute include official batch control, scientific advice and inspections. In-house experimental research in the field of biomedicines and life science form an indispensable basis for the varied and many tasks performed at the institute.
The Paul-Ehrlich-Institut, with its roughly 800 members of staff, also has advisory functions nationally (federal government, federal states (Länder)), and internationally (World Health Organisation, European Medicines Agency, European Commission, Council of Europe etc.).
Press Release on the Paul-Ehrlich-Institut Website
Dr. Susanne Stöcker | idw
Ambush in a petri dish
24.11.2017 | Friedrich-Schiller-Universität Jena
Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology
High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons
The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
24.11.2017 | Physics and Astronomy
24.11.2017 | Health and Medicine
24.11.2017 | Earth Sciences