Role of granzyme B in the aging retina

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The goal of the project is to identify the distribution of an important family of enzymes, the Granzymes, in theaging eye. Granzymes are serine proteases that were shown by our partner, ViDA Therapeutics, to play animportant role in the abnormal degradation of extracellular proteins and tissue matrices in many parts of thebody. To date, there are no studies on the role of Granzymes in the eye, an organ that contains an importantextracellular structure called Bruch's Membrane (BM). As the eye ages, the extracellular matrix (ECM) withinBM undergoes dramatic remodelling, hypothesized to lead to a dysfunctional blood-eye barrier. Recent studieshave shown that loss of barrier function in the outer retina causes 1) retinal cell death, 2) pro-inflammatoryevents and 3) abnormal angiogenesis and vascular permeability.The research proposed will provide relevant and novel information about the cellular distribution ofGranzyme B in the aging eye that will allow us to understand Granzyme B's role in ECM remodeling. Thehypothesis is that with aging, levels of Granzyme B increase in the choroidal tissues, leading to a compromisedBM and concomitant loss of tight junctional proteins, dysregulated barrier function, increased vascularpermeability, angiogenesis and pro-inflammation. Eye tissues from postmortem human donors (ranging from16yr to 80yrs of age) and wild type mice (C57Bl/6J, 3 to 18 months of age) will be assessed for longitudinalchanges in protein levels of Granzyme B, cytokines (IL1b; IL1a), tight junctional proteins (ZO-1, cadherins),and angiogenic factors (VEGF, bFGF). Immunohistochemistry will identify the laminar distribution whileantibody-based multiplexes will provide quantitative values (pg/mL) of these molecules in the retina. Opticalimaging of the retina in Granzyme B knock-out mice and in aged mice treated with Granzyme B inhibitors willassess Granzyme B-induced changes in retinal structure in vivo. Key benefits include new target areas forpartner's proprietary Granzyme B inhibitors. Future economic and social benefits include potential newtreatments for Canadians suffering from chronic ocular inflammation.