When suppressing immunity is a good thing

A receptor, first known for its role in mediating the harmful effects of the environmental pollutant dioxin in our body, is now understood to play other important roles in modulating the innate immune response.

This image shows the AHR-mediated braking mechanism for the regulation of the...
This image shows the AHR-mediated "braking" mechanism for the regulation of the antiviral IFN response.
Source: Akinori TAKAOKA, Hokkaido University

Our immune system is vital as a protective mechanism against foreign agents, including viruses and bacteria. However, an exaggerated immune response can have damaging effects on the body, as is the case in autoimmune diseases, for example. The regulation of this system is thus important.

More than 35 years ago, researchers discovered the aryl hydrocarbon receptor (AHR) as the mediator of dioxin toxicity in the body. When dioxin enters the body, it binds to AHR, which in turn activates target genes that encode proteins, including one called TIPARP. This then goes on to play a role in the body's reactions to the toxic pollutant.

Now, a team of scientists from Japan's Hokkaido University together with colleagues from Canada and Norway have found that AHR also plays a role in regulating the body's innate immune response to viral infections.

By analysing mouse cells deficient in AHR and comparing the results with cells containing AHR, they found that the activation of this receptor by amino acid metabolites negatively regulates the production of an antiviral protein called type I interferon (IFN-I). It does this by activating the gene that encodes the protein TIPARP, which in turn interferes with the pathway that stimulates interferon production upon viral infection. AHR-mediated "braking" mechanism may help protect the host from harmful effects caused by excessive IFN-I activation. Also, AHR might reduce the body's immune response against viral infection during times of stress and nutritional impairments due to the production of substances that activate the receptor.

Identifying the substances and factors that regulate the pathways that are stimulated by AHR activation could have clinical implications for controlling pathological innate immune responses, the researchers say.


Source: Hokkaido University

14.07.2016

Read all latest stories

Related articles

Photo

Mitochondria research

Colorectal cancer: Mutations in overlooked DNA could have huge impact on survival

DNA errors in the cell’s energy ‘factories’ increases the chances of survival for people with bowel cancer, also known as colorectal cancer, according to a new study. Studying how DNA errors…

Photo

Regenerative properties discovered

Reprogramming immune cells to repair tissue damage

Regulatory T cells (Treg cells) are an immune cell type that reduces excessive immune responses and protects the body against autoimmune diseases. A new study shows that Treg cells in human tissues…

Photo

Proof of concept

Surveillance system tracks Covid infection hotspots in hospital

A University of Manchester team has applied new techniques to detect and track the transmission of Covid-19 in hospital. The proof of concept system combines the movement and interaction of staff and…

Related products

FUJIFILM Wako - Autokit CH50 Assay

Clinical Chemistry

FUJIFILM Wako - Autokit CH50 Assay

Wako Chemicals GmbH
Lifotronic - FA-160 Immunofluorescence Analyzer

Other

Lifotronic - FA-160 Immunofluorescence Analyzer

Lifotronic Technology Co., Ltd
Mindray – BC-6200 / 6000 Auto Hematology Analyzer

Blood Cell Couner

Mindray – BC-6200 / 6000 Auto Hematology Analyzer

Shenzhen Mindray Bio-Medical Electronics Co., Ltd
Sarstedt – Cell Culture Products

Specialties

Sarstedt – Cell Culture Products

SARSTEDT AG & CO. KG
Sarstedt – Low DNA Binding Micro Tubes

Research Use Only (RUO)

Sarstedt – Low DNA Binding Micro Tubes

SARSTEDT AG & CO. KG
Subscribe to Newsletter