[Pathological consequences of excess of interferon in vivo]

Animal Models for the Study of Nucleic Acid Immunity: Novel Tools and New Perspectives

Unresolved inflammation fosters and supports a wide range of human pathologies. There is growing evidence for a role played by cytosolic nucleic acids in initiating and supporting pathological chronic inflammation. In particular, the cGAS-STING pathway has emerged as central to the mounting of nucleic acid-dependent type I interferon responses, leading to the identification of small-molecule modulators of STING that have raised clinical interest. However, several new challenges have emerged, representing potential obstacles to efficient clinical translation. Indeed, the current literature underscores that nucleic acid-induced inflammatory responses are subjected to several layers of regulation, further suggesting complex coordination at the cell-type, tissue or organism level. Untangling the underlying processes is paramount to the identification of specific therapeutic strategies targeting deleterious inflammation. Herein, we present an overview of human pathologies presenting with deregulated interferon levels and with accumulation of cytosolic nucleic acids. We focus on the central role of the STING adaptor protein in these pathologies and discuss how in vivo models have forged our current understanding of nucleic acid immunity. We present our opinion on the advantages and limitations of zebrafish and mice models to highlight their complementarity for the study of inflammatory human pathologies and the development of therapeutics. Finally, we discuss high-throughput screening strategies that generate multi-parametric datasets that allow integrative analysis of heterogeneous information (imaging and omics approaches). These approaches are likely to structure the future of screening strategies for the treatment of human pathologies.

[Cytosolic DNA sensing by the cGAS-STING pathway in cancer]

Cyclic GMP-AMP synthase (cGAS) is a universal cytosolic DNA sensor that detects nucleic acids of pathogens. Upon DNA sensing, cGAS triggers the formation of the second intracellular messenger, the cyclic GMP-AMP (cGAMP), which activates the adaptor STING. STING engagement induces the secretion of cytokines and type I interferons that contribute to pathogen clearance. However, there is emerging evidence that cGAS is activated by self DNA in cancer cells and in antigen-presenting cells to trigger an antitumoral response. In this review, we will highlight the current understanding of self DNA sensing by cGAS in the context of cancer.