PROJECT SUMMARY Aging is a significant risk factor for age-related macular degeneration AMD, a leading cause of blindness among the elderly. Aging and AMD induce progressive changes in Bruch’s membrane but to varying extents. There is increasing evidence that the physical properties of tissues, particularly the extracellular matrix (ECM) can influence tissue homeostasis and function. The ECM plays a critical role in the biomechanical properties of tissue. Deciphering the protein composition of the ECM and how it changes in the context of aging and disease pathology is an important first step towards understanding its role in health and disease especially in the eye. The matrisome of Bruch’s membrane has not yet been described, but it could potentially represent a vast and untapped reservoir of disease biomarkers. In this proposal we will describe the spatial and temporal matrisome maps of RPE/Bruch’s membrane/choriocapillaris and correlate it with underlying stiffness of Bruch’s membrane. Taken together this study will describe the spatial mapping of Bruch’s membrane stiffness and matrisome in mouse and human eyes, identify changes with aging and provide mechanistic insights into how changes in stiffness can regulate RPE barrier function and metabolism.