Prostate cancer-derived anti-GRP78 autoantibodies compromise the blood-brain barrier and accelerate atherosclerosis progression in vivo.
Conferences
Overview
Research
Identity
Additional Document Info
View All
Overview
abstract
205 Background: Pathological conditions of prostate cancer (PCa) drive the translocation of the endoplasmic reticulum-resident chaperone, GRP78, to the cell surface (cs) where it acts as an antigenic protein with signaling properties. In PCa, csGRP78 drives the production of anti-GRP78 autoantibodies (AutoAbs) that engage csGRP78 and promote PCa survival/progression. New studies now demonstrate csGRP78 expression on endothelial cells (EC) that line the arterial vasculature and the blood-brain barrier (BBB) suggesting that these AutoAbs can affect other systems in the body. Based on this, we investigated how the engagement of anti-GRP78 AutoAbs to csGRP78 on EC can contribute to EC-dysfunction that can promote atherosclerosis and compromise the integrity of the BBB. Methods: Anti-GRP78 AutoAbs were purified from PCa patients (St. Joseph’s Healthcare Hamilton); human aortic EC and the ApoE -/- mouse model were used for in vitro and in vivo investigations, respectively. EC or mice were treated with anti-GRP78 AutoAbs or IgG control (60µg/mL); EC-dysfunction was investigated by measuring attachment protein expression, in vitro. In vivo evaluation was carried out by studying atherosclerotic plaque progression (immunohistochemistry; aorta); the BBB integrity was examined using the Evans Blue dye. Results: Mice injected with anti-GRP78 AutoAbs, and not human IgG, demonstrated larger atherosclerotic plaque volume and hallmarks of a leaky BBB. In terms of a mechanism, in vitro studies demonstrated that treating EC with anti-GRP78 AutoAbs resulted in activation of the NFκB pathway that led to increased expression of attachment proteins. All these effects were reversed by using a recombinant molecule that interfere with the binding of the AutoAb to csGRP78. Conclusions: We have identified anti-GRP78 AutoAb as a driver of EC-dysfunction that promote atherosclerotic plaque progression and damage to the BBB. Our results indicate that interfering with anti-GRP78 AutoAb:csGRP78 complex can reverse the pathological effects of the AutoAbs. This novel data suggests that patient-derived anti-GRP78 autoantibodies systemically drive pathologies, other than cancer, in vivo.
