• DNA Damage Primes the Type I Interferon System via the Cytosolic DNA Sensor STING to Promote Anti-Microbial Innate Immunity.

      Härtlova, Anetta; Erttmann, Saskia F; Raffi, Faizal Am; Schmalz, Anja M; Resch, Ulrike; Anugula, Sharath; Lienenklaus, Stefan; Nilsson, Lisa M; Kröger, Andrea; Nilsson, Jonas A; et al. (2015-02-17)
      Dysfunction in Ataxia-telangiectasia mutated (ATM), a central component of the DNA repair machinery, results in Ataxia Telangiectasia (AT), a cancer-prone disease with a variety of inflammatory manifestations. By analyzing AT patient samples and Atm(-/-) mice, we found that unrepaired DNA lesions induce type I interferons (IFNs), resulting in enhanced anti-viral and anti-bacterial responses in Atm(-/-) mice. Priming of the type I interferon system by DNA damage involved release of DNA into the cytoplasm where it activated the cytosolic DNA sensing STING-mediated pathway, which in turn enhanced responses to innate stimuli by activating the expression of Toll-like receptors, RIG-I-like receptors, cytoplasmic DNA sensors, and their downstream signaling partners. This study provides a potential explanation for the inflammatory phenotype of AT patients and establishes damaged DNA as a cell intrinsic danger signal that primes the innate immune system for a rapid and amplified response to microbial and environmental threats.
    • Growing tumors induce a local STING dependent Type I IFN response in dendritic cells.

      Andzinski, Lisa; Spanier, Julia; Kasnitz, Nadine; Kröger, Andrea; Jin, Lei; Brinkmann, Melanie M; Kalinke, Ulrich; Weiss, Siegfried; Jablonska, Jadwiga; Lienenklaus, Stefan; et al. (2016-09-15)
      The importance of endogenous Type I IFNs in cancer immune surveillance is well established by now. Their role in polarization of tumor-associated neutrophilic granulocytes into anti-tumor effector cells has been recently demonstrated. Yet, the cellular source of Type I IFNs as well as the mode of induction is not clearly defined. Here, we demonstrate that IFN-β is induced by growing murine tumors. Induction is mainly mediated via STING-dependent signaling pathways, suggesting tumor derived DNA as trigger. Transcription factors IRF3 and IRF5 were activated under these conditions which is consistent with tumor infiltrating dendritic cells (DCs) being the major cellular source of IFN-β at the tumor site. Besides DCs, tumor cells themselves are induced to contribute to the production of IFN-β. Taken together, our data provide further information on immune surveillance by Type I IFNs and suggest novel potent cellular targets for future cancer therapy.