Mark Minie

Cutting Edge: Antimalarial Drugs Inhibit IFN-β Production through Blockade of Cyclic GMP-AMP Synthase–DNA Interaction

Type I IFN is strongly implicated in the pathogenesis of systemic autoimmune diseases, such as lupus, and rare monogenic IFNopathies, including Aicardi–Goutières syndrome. Recently, a new DNA-activated pathway involving the enzyme cyclic GMP-AMP synthase (cGAS) was described and potentially linked to Aicardi–Goutières syndrome. To identify drugs that could potentially inhibit cGAS activity, we performed in silico screening of drug libraries. By computational analysis, we identified several antimalarial drugs (AMDs) that were predicted to interact with the cGAS/dsDNA complex. Our studies validated that several AMDs were effective inhibitors of IFN-β production and that they functioned by inhibiting dsDNA stimulation of cGAS. Because AMDs have been widely used in human diseases and have an excellent safety profile, our findings suggest new therapeutic strategies for the treatment of severe debilitating diseases associated with type I IFNs due to cGAS activation.

Antimalarial Drugs as Immune Modulators: New Mechanisms for Old Drugs

The best known of the naturally occurring antimalarial compounds are quinine, extracted from cinchona bark, and artemisinin (qinghao), extracted from Artemisia annua in China. These and other derivatives are now chemically synthesized and remain the mainstay of therapy to treat malaria. The beneficial effects of several of the antimalarial drugs (AMDs) on clinical features of autoimmune disorders were discovered by chance during World War II. In this review, we discuss the chemistry of AMDs and their mechanisms of action, emphasizing how they may impact multiple pathways of innate immunity. These pathways include Toll-like receptors and the recently described cGAS-STING pathway. Finally, we discuss the current and future impact of AMDs on systemic lupus erythematosus, rheumatoid arthritis, and devastating monogenic disorders (interferonopathies) characterized by expression of type I interferon in the brain.

Bioinformatics Challenges and Opportunities

As biomedical research and healthcare continue to progress in the genomic/post genomic era a number of important challenges and opportunities exist in the broad area of biomedical informatics. In the context of this chapter we define bioinformatics as the field that focuses on information, data, and knowledge in the context of biological and biomedical research. The key challenges to bioinformatics essentially all relate to the current flood of raw data, aggregate information, and evolving knowledge arising from the study of the genome and its manifestation. In this chapter we first briefly review the source of this data. We then provide some informatics frameworks for organizing and thinking about challenges and opportunities in bioinformatics. We use then use one informatics framework to illustrate specific challenges from the informatics perspective. As a contrast we provide also an alternate perspective of the challenges and opportunities from the biological point of view. Both perspectives are then illustrated with case studies related to identifying and addressing challenges for bioinformatics in the real world.

The Promise and Challenge of Digital Biology

The era of Digital Biology began in 2010 with the “rebooting” of a bacterial cell using a synthetic DNA genome created from a digital template stored on a computer [1]. With this event, the creation of Mycoplasma laboratorium (nicknamed “Synthea”), came the first complete proof that DNA was the true software of life. Cells could be simulated digitally and the simulations could be tested against reality by reprograming cytoplasm with synthetic genomes generated from the digital DNA sequences driving those simulations. This in turn has created the expectation and promise that a deeper understanding of cellular function and thus life itself could be achieved on an infinite iterative loop of computer modeling and chemical synthesis (Figure 1) [2].

Inhibition of Cyclic GMP‐AMP Synthase Using a Novel Antimalarial Drug Derivative in Trex1‐Deficient Mice

Type I interferon (IFN) is strongly implicated in the pathogenesis of systemic lupus erythematosus (SLE) as well as rare monogenic interferonopathies such as Aicardi‐Goutières syndrome (AGS), a disease attributed to mutations in the DNA exonuclease TREX1. The DNA‐activated type I IFN pathway cyclic GMP‐AMP (cGAMP) synthase (cGAS) is linked to subsets of AGS and lupus. This study was undertaken to identify inhibitors of the DNA–cGAS interaction, and to test the lead candidate drug, X6, in a mouse model of AGS.

I-01 Novel mechanism of action of anti-malarial drugs in the inhibition of type I interferon production

Background Anti-malarial drugs (AMD) such as Hydroxychloroquine (HCQ) and Quinacrine (QC) are effective in the treatment of skin rash and arthritis in systemic lupus erythematosus (SLE). However, which mechanism(s) are responsible for their beneficial action is uncertain. Type I interferon, (IFN-I) is strongly implicated in the pathogenesis of SLE and ‘interferonopathies’ such as Aicardi-Goutieres Syndrome (AGS) A new DNA activated IFN-I pathway, cyclic GMP-AMP (cGAMP) synthase (cGAS), was recently discovered and linked to AGS and mouse models of Lupus. Preliminary data indicate that a subset of SLE patients also have elevated cGAs and cGAMP (the cyclic dinucleotide responsible for activation of STING and IFN-I. Materials and methods In silico structure-based drug screening were provided by the CANDO docking algorithm. Predictions made by CANDO were confirmed by Autodock Vina and analysed via PyMOL. cGAS activity/cGAMP production was analysed by Thin Layer Chromatography (TLC). DNA-binding to cGAS in the presence or absence of AMD was determined by an Electrophoretic Mobility Shift Assay (EMSA). Following DNA cell transfections, cytokines were quantified by qPCR, ELISA or an ISRE-luciferase reporter assay. cGAMP in patient samples was quantified by mass spectrometry. Results In silico screening of drug libraries identified several antimalarial drugs (AMD) which could potentially inhibit cGAS activity by interacting with cGAS/DNA dimer complex. Electrophoretic Mobility Shift Assay revealed that AMD disrupted the double stranded DNA-cGAS complex in a dose dependent manner. These AMD also inhibited IFN-I expression in THP1 cells transfected with dsDNA and in 293 T cells transfected with cGAS/STING plasmids validating that cGAS is a target of AMD. We synthesisedsynthesized several new AMD. One of these compounds, X6, had excellent water solubility and cell penetration. X6 localised to the cytosol and had a lower toxicity profile compared to QC. Biochemical and cellular assays revealed that X6 was a more potent inhibitor of IFN-I production than HCQ. We also validated mechanism of action and proof of concept in the animal model of AGS. Conclusions Our studies identify new DNA sensor cGAS as a target of AMD activity, which provide a novel mechanism of action of these AMD. We have synthesised new AMD like drugs that are also able to inhibit cGAS as well as Toll pathways. These drugs could be beneficial for the treatment of AGS and/or Lupus.

Inviting the public: the impact on informatics arising from emerging global health research paradigms.

This workshop will focus on disruptive processes impacting research arising from the increasing ability of individuals to create, curate and share data with scientists. Encompassing processes from funding research to providing samples to creating algorithms, including the public will require new approaches even as it opens up new possibilities. We will hear from a few researchers at the forefront of these disruptive processes, followed by a moderated discussion with the audience about these topics.