Engineered DNA-particles to model immune events in systemic lupus erythematosus

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Summary/Abstract Systemic lupus erythematosus (SLE or lupus) is a prototypic autoimmune disease that causes severe systemic manifestations, of which nephritis is the major cause of morbidity and mortality. SLE primarily affects young women, with African American patients showing much earlier and more severe disease than European Americans. An important feature of SLE is the expression of antibodies to nuclear molecules (anti-nuclear antibodies (ANAs)). ANAs provide serological markers for diagnosis, classification, and disease activity. While there has been extensive study of the pathogenesis of SLE, much remains unknown about the underlying mechanisms that promote inflammation and renal injury. As a result, SLE treatment is empiric and frequently ineffective. Current treatments can cause permanent organ damage and severe side effects, providing a strong rationale for the mechanistic studies necessary for more effective and less toxic therapies. In patients as well as animal models of SLE, the formation of immune complexes by ANAs is a key step in inflammation and injury. Of ANAs that can form immune complexes, antibodies to DNA (anti-DNA) have a prominent and well-validated role in nephritis, as shown by the isolation of anti-DNA from affected kidneys of patients, as well as the induction of nephritis in animal models by administration of monoclonal anti-DNA antibodies. While most models for immune complexes are based on antibody interaction with soluble protein or nucleic acid antigens of relatively low molecular weight, recent research suggests that immune complexes in SLE form on cell-generated particles known as extracellular vesicles. We propose that DNA can adsorb onto the surface of these particles to form a “corona” that provides a target for anti-DNA antibodies. The significance of this research is the development of well-controlled synthetic DNA-particles to address fundamental questions about the immunological properties of particles that are not addressable with naturally occurring particles. The outcome of this research will be the understanding of the mechanisms by which DNA binds to particles to form an antigenic substrate; the formation of immune complexes by particles; the effects of surface DNA on the interaction of particles with immune cells; and the role of surface DNA in immune stimulation. Aim 1 will determine the antigenicity of DNA adsorbed on particles as a function of particle diameter, DNA length, and a protein corona using a previously developed antibody binding assay as a readout. Aim 2 will use the antigenic particles identified in Aim 1 to elucidate the immunostimulatory activity of DNA-particles in vitro, measuring the immune response and cellular internalization of the DNA-particles. The development of a well-controlled synthetic particle system provides an innovative approach to the study of SLE. Beyond SLE, the role of naturally occurring, cell-generated particles as elements in disease pathogenesis has important implications for other autoimmune and inflammatory diseases. 0