High-throughput screen identifies non inflammatory small molecule inducers of trained immunity.

Trained immunity is characterized by epigenetic and metabolic reprogramming in response to specific stimuli. This rewiring can result in increased cytokine and effector responses to pathogenic challenges, providing nonspecific protection against disease. It may also improve immune responses to established immunotherapeutics and vaccines. Despite its promise for next-generation therapeutic design, most current understanding and experimentation is conducted with complex and heterogeneous biologically derived molecules, such as ß-glucan or the Bacillus Calmette-Guérin (BCG) vaccine. This limited collection of training compounds also limits the study of the genes most involved in training responses as each molecule has both training and nontraining effects. Small molecules with tunable pharmacokinetics and delivery modalities would both assist in the study of trained immunity and its future applications. To identify small molecule inducers of trained immunity, we screened a library of 2,000 drugs and drug-like compounds. Identification of well-defined compounds can improve our understanding of innate immune memory and broaden the scope of its clinical applications. We identified over two dozen small molecules in several chemical classes that induce a training phenotype in the absence of initial immune activation-a current limitation of reported inducers of training. A surprising result was the identification of glucocorticoids, traditionally considered immunosuppressive, providing an unprecedented link between glucocorticoids and trained innate immunity. We chose seven of these top candidates to characterize and establish training activity in vivo. In this work, we expand the number of compounds known to induce trained immunity, creating alternative avenues for studying and applying innate immune training.

Robust tolerogenic dendritic cells via push/pull pairing of toll-like-receptor agonists and immunomodulators reduces EAE.

A failure of central immune tolerance driven by autoantigen specific T regulatory (Treg) cells is a major cause of many autoimmune diseases. Restoration of proper autoantigen Treg specific response holds promise as a highly effective, long-term therapy for a wide variety of autoimmune diseases. Generating autoantigen specific Tregs remains a challenge due to the non-specific nature of most tolerizing agents and the complexities of generating Tregs in vivo. Here we show a new push/pull method for inducing antigen-specific Treg tolerance via induction of tolerogenic dendritic cells (tolDCs). We identified a combination of three tolerogenic drugs, dexamethasone, simvastatin and SC-514, which when used in combination with toll-like-receptor (TLR) agonists induces an active tolDC phenotype. When the tolerogenic combination was packaged into a liposome with a model antigen such as ovalbumin (OVA), these tolDCs induce differentiation of OVA specific Tregs both ex vivo and in vivo. We examined the tolerizing potential of the combination in an experimental autoimmune encephalomyelitis (EAE) disease model. Given the antigen specificity of this technique, this paper presents an attractive preclinical autoimmune therapy.