Fig. 1

PAMP and DAMP stimulation of pattern recognition receptors within the retina. An overview of the different pathogen-associated molecular patterns and damage-associated molecular patterns that can stimulate pattern recognition receptors in the retina. Pattern recognition receptors are critical for host defence responses to pathogen infections. Pathogens such as bacteria, viruses, and fungi present pathogen-associated molecular patterns that stimulate toll-like and NOD-like receptors. In age-related macular degeneration and experimental models of macular degeneration, damage-associated molecular patterns have been shown to injure retinal pigment cells and amplify inflammatory responses. Damage-associated molecular patterns of Alu RNA, fibrinogen, and Aβ-oligomer found within drusen, ROS, ATP, HMBG-1 released by damaged/dying photoreceptors and cathepsin from retinal pigment cells have been shown to stimulate either toll-like receptors and NOD-like receptors, on retinal pigment cells or innate immune cells that are found within the subretinal space. (Amyloid β-oligomer – Aβ-oligomer, ATP – Adenosine Tri Phosphate, BM – Bruch’s Membrane, CC – Choriocapillaris, DAMP – Danger Associated Molecular Pattern, HMBG-1 - High mobility group box 1 protein, PAMP – Pattern Associated Molecular Pattern, PR – Photoreceptor – PRR – Pattern Recognition Receptors – RPE – Retinal Pigment Epithelium ROS – Reactive Oxidative Species – SR – Subretinal space)