Abstract 440: Targeting LOX-1 Scavenger Receptor and oxLDL Uptake With Affimers

Introduction: Lectin-like oxidized low density lipoprotein receptor 1 (LOX-1, SREC-1, OLR1) is a class E scavenger receptor which binds oxidized low density lipoprotein (oxLDL) particles implicated in promoting atherosclerosis. Affimers are non-antibody synthetic protein-based scaffolds that enable recognition of a wide range of molecular targets. Aims: To investigate the ability of Affimers to bind LOX-1 and modulate oxLDL accumulation and effects on cellular responses. Methods: Recombinant soluble human LOX-1 was screened with an Affimer library and LOX-1-specific Affimers were isolated and characterized. Human embryonic kidney (HEK293T) cells inducibly expressing human LOX-1 were incubated with labeled oxLDL and Affimers to modulate LOX-1 and oxLDL uptake and trafficking. Furthermore, Affimer-mediated effects on oxLDL-regulated metabolism and apoptosis was evaluated. Results: Five Affimers specific for human LOX-1 were identified. Fluorescent labelled Affimers demonstrate specific binding to LOX-1 expressing HEK293T cells and modulate LOX-1 and oxLDL trafficking and accumulation in endosomes and lysosomes. LOX-1-specific Affimers also show effects in modulating oxLDL-mediated effects in specific cellular responses. Conclusion: LOX-1-specific Affimers are a new class of synthetic molecules that have therapeutic potential in targeting LOX-1, a key mediator of inflammation and arterial dysfunction in cardiovascular disease. Membrane specific binding is demonstrated only in induced LOX-1 expressing cells (LOX+). Increasing concentration of affimer prior to incubation with DiI labelled oxLDL.