2016Joint Usage and Research Report
Title of Research Project

Role of AHR-inducible ADP-ribosyltransferase
TIPARP in the innate defense system

ApplicantInstitution

University of OsloJob title

Professor Jason Matthews

and nameVisiting

NameProfessor Jason Matthews

researcher
Purpose of the Research Project

The AHR is a ligand-activated transcription factor that is(approx. 250 words)

activated by many environmental xenobiotics, dietary products
and endogenous metabolites. Despite its notoriety as a mediatorof toxicological responses, the AHR has emerged as an important
regulator of numerous physiological processes, including theimmune system and in T cell differentiation. However, its role in
the innate immune response after viral infection is incompletelyunderstood. We reported that TIPARP, an AHR target gene andADP-ribosyltransferase, is a critical regulator of many aspects ofAHR activity. TIPARP has also been reported to play a role inviral replication and inflammation. Together with Dr. Takaoka
and colleagues, we recently reported that TIPARP is the key
regulator of AHR-dependent innate immune suppression.
Moreover, we found that TIPARP specifically ADP-ribosylates
TBK1 reducing its ability to activate type I interferon responses.
This suggests that pharmacological inhibition of TIPARP could
be a beneficial anti-viral therapy. This work was published inYamada et al. Nature Immunology 2016. We now plan to further
determine the importance of TIPARP in the innate immune
response and its potential role in T cell function. These future
projects will include comprehensive studies of Tiparp knockout
mice and T-cell specific Tiparp knockout mice that will begenerated using floxed Tiparp (Tiparpfl/fl) mice. We will also use
mass spectrometry to identify proteins that are modified byTIPARP and map the modified sites.

Development of the Research

The research project has continued as outlined in our initial

Project and Results

proposal. We want to build on our findings from our first(approx.. 850 words)

manuscript that was published last year. My lab has used mass
spectrometry to identify ADP-ribosylated peptides in TIPARPand AHR. In collaboration with Dr. Takaoka, we will use thesame approach to map the ADP-ribosylated sites in TBK1. We
have received protein as well as expression plasmids from Dr.
Takaoka’s lab to pursue this research. We have struggled withprotein expression and optimization of the ADP-ribosylation andmass spectrometry for TBK1. However, many of the initialproblems we have been having, such as poor yield, have beensolved. Dr. Takaoka has also found that many virus’ induce theexpression of TIPARP in a manner that is independent of AHR.
This intriguing finding potentially uncovers a novel feedback
regulation

involving

viralinfection,

pathogenassociatedmolecular patterns and TIPARP. We are working together, to try
to uncover this mechanism behind this interplay by using avariety of molecular approaches. To further understand the roleof the AHR-TIPARP axis in innate immunity, I have provided Dr.
Takaoka’s lab with Tiparp knockout mice as well as Tiparp fl/fl
mice. These mice are presently being rederived from frozen
embryos. We anticipate being able to use the mice inexperiments later this spring or early summer. The knockout
mice will be exposed to various viruses and a number of relevant
endpoints determined. The Tiparpfl/fl mice will be used to maketissue or cell type specific deletions of Tiparp to provide moreinsight into its role in innate immunity. My lab has recently
generated a catalytic mutant Tiparp mouse using CRISPR-Cas9.
We have isolated mouse embryonic fibroblasts and plan to sharethese cells as well as the mice with Dr. Takaoka to further
enhance the quality of the data generated in this project.
Preliminary data on these mice, suggest that they exhibit
similar phenotypes following AHR activation as Tiparp knockout
mice. This suggests that Tiparp’s role in AHR signaling andphysiology is dependent on its catalytic activity. This uniquemouse model will be instrumental in demonstrating theimportance of Tiparp catalytic activity in mediating its role ininnate immunity.

Publication【Conference, symposium, workshop etc.】*Enter the names of conferenceor journal and its vol. No. where
the above work was presented.
【Journals】
1. Yamada, T., Horimoto, H., Hayakawa, S., Kameyama, T.,
Yamato, H., Dazai, M., Takada A., Kida, H., Asaka, M., Bott,D., Hutin, D., Zhou, A., and Watts, T., Matthews, J. andTakaoka, A. (2016) TIPARP ADP-ribosyltransferase LinksAHR Signaling to Innate Immune Suppression. NatureImmunology 17:687-694.